tional Museum through the great kindness of Dr. Leonhard Stejneger, is thoroughly representative for the whole western hemisphere and includes many forms from all other parts of the world, Africa, Europe, temperate Asia, the East Indies and Australia being well represented. Southern Asia is the only region from which there is but little material. Clear presentation of the taxonomic conditions shown in the rather large amount of data necessitates a more elaborate classification of the Opalinidæ than that generally in use. In the year 1918 I published a classification of the Opalinidæ. The completed review of all the material shows that this classification, if elaborated somewhat will be a clearer expression of the real facts. I therefore now propose the following classification: The Opalinidæ are placed as an appendage of the Ciliata, being separated from the other Ciliata by the fact that they have not developed macronuclei and micronuclei, and by some features of their life history. They show, both in their structure and possibly in their life history, decided indication of relationship to the Trichonymphide which are usually regarded as an appendage of the Flagellata. From the Opalinidæ I exclude all the genera of Ciliata astomata, which have nuclei of two sorts, leaving, only those forms which, with the exception of my own recent usage, have been included in the genus Opalina. The Opalinidæ include both binucleated and multinucleated species and these should be assigned to distinct subfamilies. The Protoopalininæ include the genera Protoopalina (cylindrical binucleated forms) and Zelleriella1 (flattened binucleated forms). The Opalininæ also include two genera, Cepedea2 (cylindrical multinucleated species) and Opalina (flattened multinucleated species). The latter genus includes two groups of species-the western hemisphere forms, which are for the most part narrow, especially posteriorly, and the eastern hemisphere spe cies, all of which are broad. All the other Ciliata may be classed as Euciliata in distinction from the Protociliata which include only the Opalinidæ. There are two species which do not accurately fit into this classification as defined. They are Protoopalina quadrinucleata from Rana macrodon of Java and Protoopalina axonucleata from Bufo bufo asiaticus of eastern Asia. These species will be described in a paper soon to go to press. They are mentioned here merely because the former usually has four nuclei and the latter usually shows six to twelve nuclei. They are transitional forms between the genera Protoopalina and Cepedea, but are classed with the former genus because of the histological character of their nuclei which resembles that of the Protoopalina nucleus. MAYNARD M. METCALF THE ORCHARD LABORATORY, THE OHIO ACADEMY OF SCIENCE THE thirtieth annual meeting of the Ohio Academy of Science was held at the Ohio State University, Columbus, May 14 and 15, 1920, under the presidency of Professor F. C. Blake. Sixty-nine members were registered as present; thirty new members were elected. The executive committee reported the completion of the affiliation of the academy with the American Association for the Advancement of Science in accordance with the plan adopted by the association at the Christmas meeting. 1 Named for Ernest Zeller who in the year 1877 published a fine paper upon the European species of the family. 2 Named for Cassimer Cepede whose studies upon Ciliata astomata clearly showed that the Opalinidæ are to be regarded as quite distinct from the other astomatous forms. It was reported by the trustees of the Research Fund that Mr. Emerson McMillin, of New York City, had made a further contribution of two hundred and fifty dollars to the research fund. In view of his continued financial support of the research work of the academy Mr. McMillin was elected a patron; he was also elected to fellowship in the academy on the strength of his own contributions to science. The following special resolutions were adopted by the academy: 1. Recording appreciation of the work of the Ohio Biological Survey and expressing the hope that its work, now financially crippled, may be continued with increased support. 2. Urging the utmost watchfulness in the conservation of platinum and condemning its use "in jewelry and in any other way that is not productive of scientific or industrial advance or development."' 3. Urging a like conservation of potassium and the use, wherever practicable, of sodium salts as a substitute for potassium salts in scientific and commercial work. 4. Endorsing the work of the State Department of Agriculture in establishing preserves for game and other wild life of the state, and appointing a committee to cooperate in this work. This committee, under the chairmanship of Professor Herbert Osborn, of Ohio State University, is in position to cooperate also in the nation-wide movement in this direction instituted by the Ecological Society of America and endorsed by the American Association for the Advancement of Science. Officers were elected as follows: President, W. H. Alexander, Weather Bureau, Columbus; Vicepresidents: Zoology, F. H. Krecker, Ohio State University; Botany, C. H. Otis, Western Reserve University; Geology, W. H. Bucher, University of Cincinnati; Physics, D. C. Miller, Case School of Applied Science; Medical Sciences, Ernest Scott, Ohio State University; Psychology, H. A. Aikins, Western Reserve University; Secretary, E. L. Rice, Ohio Wesleyan University; Treasurer, A. E. Waller, Ohio State University. The scientific program was as follows: PRESIDENTIAL ADDRESS The Einstein theory of relativity and gravitation: PROFESSOR F. C. BLAKE, Ohio State University. PUBLIC LECTURE Photographing sound waves from large guns and projectiles: PROFESSOR DAYTON C. MILLER, Case School of Applied Science. SYMPOSIUM BEFORE PHYSICS SECTION The constitution of the atom: (a) The planetary atom of the physicist: S. J. M. ALLEN; (b) Why not one kind of atom only? R. C. GOWDY; (c) Discussion led by W. L. Evans. PAPERS The Arizona boll weevil (Anthonomus grandis var. thurberia) with special reference to steps taken by the Arizona Commission of Agriculture and Horticulture to prevent its establishment in cultivated cotton: DON C. MOTE. Aphelopus theliae (Gahan) and the changes produced in Thelia by this parasite: S. I. KORN HAUSER. The intestinal parasites of overseas troops as compared with home service troops: S. I. KORN HAUSER. A new disease, black tumor, of the catfish: R. C. OSBURN. Classification of the Opalinidae: MAYNARD M. MET CALF. Geographical distribution of the Opalinidae: MAYNARD M. METCALF. Factors in the distribution of aquatic snails in Lake Erie: F. H. KRECKER. Caddis-fly larvae as agents in distribution of fresh water sponges: F. H. KRECKER. Notes on some tropical Homoptera: HERBERT OS BORN. Generic and specific characters from the male genitalia of Syrphidae (Diptera): C. L. METCALF. Some myriapods of Put-in-Bay: STEPHEN R. WIL LIAMS. Claws of arachnids: W. M. BARROWS. KINDRED. Additions to the birds of Ohio: LYNDS JONES. Two recently destructive clover insects of western The preservation of native flora and fauna: HERBERT OSBORN. New economic applications for the mangrove: H. H. M. BowMAN. The progress of revegetation in the Katmai district: ROBERT F. GRIGGS. Observations on the edge of the forest in the Katmai district: ROBERT F. GRIGGS. The influence of environment on sexual expression in the hemp: J. H. SCHAFFNER. A double mutant of the hemp: J. H. SCHAFFNER. Translocation and storage of carbohydrates in apple fruit spurs and two-year-old seedlings: SWARNA KUMER MITRA. Origin and character of schizogenous resin cavities in avocado fruits and leaves: SWARNA KUMER MITRA. Origin and character of adventitious roots in Cornus pubescence: SWARNA KUMER MITRA. Story of citrus fruits of Pinellas County, Florida: KATHARINE DOORIS SHARP. Factors controlling transpiration: JASPER D. Certain conditions that hinder the study of botany Some farm experiments in the making of syrup Partial solution of certain applied chemical problems: (a) Saving of platinum by the use of platinum crucibles in electroanalysis; (b) By a modified mercury cathode cell; (c) The determination of water in substances easily decomposable thermally: JAMES R. WITHROW. Gas combustion investigations: (a) Quartz-apparatus; (b) Central burner type; (c) Devitrification of quartz in capillaries: F. C. VILBRANDT. The thermionic tube as a useful amplifying tool of the scientist: A. D. COLE. A seasonal breakage of watch springs and its cause: SAMUEL R. WILLIAMS. Springs of minimum weight: H. C. LORD. Relations between atomic numbers and the wave lengths of X-rays: S. J. M. ALLEN. Relations between absorption coefficients and wave lengths of X-rays: S. J. M. ALLEN. Characteristic curves of different types of thermionic tubes: A. D. COLE. Thermodynamics: Louis T. MORE. Electrification by impact: HAROLD RICHARDS. On self and mutual elastance and capacitance: F. C. BLAKE. Note on a double solenoid for the production of uniform magnetic fields: S. J. BARNETT. Observations on eruptive phenomena in the Valley of Ten Thousand Smokes: ROBERT F. GRIGGS. Diastrophism still continuing in the Great Lakes region: E. L. MOSELEY. Clarion and Vanport members in Ohio: WILBER STOUT. A pre-somite human embryo: C. L. TURNER. Relation of catalase to activity: R. J. SEYMOUR. Some features of industrial fatigue: E. R. HAY HURST. Epidemic encephalitis: ERNEST SCOTT. Measurement of blood pressure by resistance of carbon discs: E. P. DURRANT. Educative characteristics of first grade children: MARY E. MILLER. A study of the lowest five per cent, of college students as determined by the army alpha examination: HELEN MARSHALL. A study of the highest five per cent. of college students as determined by the army alpha examinations: EARL R. GABLER. Experimentation in the psychology of music: ESTHER L. GATEWOOD. Mental and educational tests of the deaf: JEANNETTE REAMER. Syphilis and delinquency: FLORENCE MATEER. SCIENCE AGRICULTURAL GEOLOGY DURING reconstruction, as the present period is frequently termed, many new applications of the principles of pure science to special fields of endeavor are being made. The principles of geology thus applied during recent years have given rise to economic geology, mining geology, engineering geology, oil geology and perhaps to that branch of the subject indicated by the above title for it is not entirely new. The application of the principles of the science to the solution of the geological problems that are met in agricultural enterprises and pursuits, in brief, the relation of geology to rural welfare may appropriately be considered as agricultural geology. Such a problem is that of securing an abundant supply of pure water. In regions of copious rainfall it is essential, in those of average to minimum rainfall it is absolutely necessary to consider the properties and the structure of the substrata in their relation to water in order to obtain such a supply. Pursuant to the requirement of this necessity, the United States Geological Survey maintains a branch of service whose work is concerned with the water resources of the entire country. The purity of subsurface water depends chiefly on the filtering power of the yielding rocks. One of the best natural filters consists of residual material of considerable depth. Some rocks below this mantle are sufficiently pervious to hold, transmit, filter and consequently to yield pure water. Certain others are impervious. Another condition is found where the rocks contain joints or cracks along which water moves freely without filtration, conveying to wells or springs contamination from distant sources. This condition is a strong possibility in limestone regions. Artesian water which, in some localities, flows from wells may be found where the properties and structure of the containing rock bears such a relation to a supply of water as will produce it. Under one combination of these conditions, as in areas of jointed igneous or metamorphic rocks in the Piedmont belt, an artesian well may yield a few hundred gallons daily; under another, that of a pervious sedimentary rock overlaid by impervious ones which outcrop in a moist region of higher elevation, as in the Great Plains, the yield may be several hundred gallons per minute. Among the minerals most useful in agricultural pursuits are coal and other mineral fuels, the mineral oils (kerosene and gasoline), iron, salt, gypsum, lime, the minerals of the soil, and the fertilizer minerals yielding potash, phosphates and nitrates. The nature, quality, distribution and availability of most of these substances bear direct relations to their respective geological occurrences. In order that careful discriminations may be made in their purchase and use, those who have need for them should be familiar with their distinguishing properties and with their relative values. In numerous localities natural gas is obtained from considerable depth. Gas provides fuel and light for use in buildings and power for machinery. Examples of such uses are common in agricultural districts in the gasproducing regions from Pennsylvania and West Virginia via Illinois southwestward to Texas and in other places, where many farmers depend almost wholly on the gas wells for these services. Gasoline for the auto and the tractor is now being extensively made from natural gas. At Anaconda, Montana, the tallest smokestack in the world, 585 feet, was erected to protect vegetation from destruction by smelter gases and soil from ruin by erosion due to this loss of its vegetative cover. Ducktown, Tennessee, and other mining districts afford additional illustrations of these principles. The gases and dust from the smelters, from the blast furnaces of the steel industry and from the flues of the cement mills, through skillfully devised systems of careful collection and concentration, are soon to yield a large proportion of the potash used as fertilizer. In road building the adaptation of various materials even when only sand and clay are needed is determined by the properties of the minerals and rocks considered for this purpose and by the nature of the base on which the road is to be constructed. In locating a road along or near a slope or in any topographic position where strata outcrop, the drainage and therefore the safety and permanence of the road, or its failure, depend on the kinds of rock involved and on their structural relation. The rapidly growing use of motor vehicles emphasizes the importance of details in regard to road materials and road locations. From the rocks at the surface or below it, suitable material is obtained for buildings and other structures necessary in agricultural enterprises. Such materials are used in making brick, cement and concrete, in building roads, bridges, dams and retaining walls and in the erection of dwellings and other buildings. A knowledge of the properties and adaptations of structural materials is essential to the intelligent selection of them and to their efficient use. It is also necessary in many localities to understand thoroughly the relations of the substrata to the surface in order to choose safe locations for permanent structures. The way in which undrained areas were formed has much to do with the solution of the problems that arise when drainage is undertaken and with the kinds of soil reclaimed when the project is completed. Whether an area must be drained by means of surface ditches or whether an exit may be found through a pervious layer of rock below depends wholly on the elevation and on the nature and structure of the substrata. In arid and semi-arid regions the possibility of irrigation as well as the permanence of the aqueduct is dependent also on geologic and topographic factors. Of the sewage disposal plants which are needed on all farms most types can be located with safety in regard to water supply only by considering fully the conditions of geologic structure and materials in the vicinity. The losses of soil by erosion due to the |