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As regards the major subdivisions of the stemmed echinoderms three groups are recognized: the cystids, the blastoids, and the crinoids. These are considered as groups of equal rank. The forms of the first are earliest in time, lowest in taxonomic position, and are regarded as the ancestral types of the other two. The crinoid type itself is a very old one, dating from the Cambrian in which it is even then in a high stage of development. During the Ordivician the cystidian features had almost wholly disappeared. The crinoidal group is remarkable for the persistence it has shown in preserving its pentamerous symmetry; and although the introduction of the anal plate so disturbed it as to well nigh produce a permanent bilateral arrangement, the former was finally permanently retained.
Neocrinoidea and Palæocrinoidea, the two primary groups of crinoids which were formerly almost universally recognized, are abandoned. In their stead are recognized three principal subdivisions: Inadunata, Camerata and Articulata. It is quite remarkable that this ternate grouping of the crinoids is essentially the same as Wachsmuth originally proposed more than twenty years ago, and that often being compelled by students of the recent forms to abandon it and to substitute others, a careful survey in the light of recent discoveries of all crinoids both fossil and living has clearly shown that the main subdivisions first suggested are essentially valid and are applicable to all known forms. The criteria for separating the crinoids into orders are briefly as follows:
1. Condition of arms, whether free above the radials or partly incorporated in the calyx.
2. Mode of union between plates of the calyx, whether movable or rigid.
3. Growth of stem, whether new plates are formed beneath the proximal ring of the calyx or beneath the top stem joint.
The simplest forms, the Crinoidea Inadunata, have the dorsal cup composed invariably of only two circlets of plates or three where infrabasals are present; there are no supplementary ossicles except an anal piece, which is, however, not always present; the arms are free from the radials up. In the construction of the ventral disk two different plans are recognizable, and upon these are established two sub-groups, the Larviformia and Fistulata. The former has the disk in its simplest possible form, being composed of five large orals arranged in a pyramid; the second has the ventral side extended into a sac or closed tube often reaching beyond the ends of the arms.
The Camerata are distinguished by the large number of supplementary pieces which bring the proximal arm plates into the calyx, thus enlarging the visceral cavity; all plates are heavy and immovable; the mouth and food grooves are tightly closed.
The Articulata have to some extent the incorporation of the lower arm plates with the calyx, but the plates are movable instead of rigid. The mouth and food grooves are open. The infrabasals are fused with the top stem joint which is not the youngest plate of the stalk. According to whether or not pinnules are present two suborders are recognized the Pinnata and Impinnata.
An analytical synopsis of the families of Camerata as proposed by the authors and as now understood is as follows:
I. Lower brachials and interbrachials forming an important part of the dorsal cup.
A. INTERRADIALS POORLY DEFINED.
The lower plates of the rays more or less completely separated from the primary interradials by irregular supplementary pieces; dicyclic or monocyclic
B. INTERRADIALS WELL DEFINED.
a. Radials in contact except at the posterior side
b. Radials separated all around
a. Radials in contact all around.
Symmetry of the dorsal cup, if not strictly pentamerous, disturbed by the introduction of anals between the brachials only
Arms borne in compartments formed by partitions attached to tegmen; dorsal cup perfectly pentamerous; plates of calyx limited to a definite number
b. Radials in contact except at the posterior side, where they are separated by an anal plate.
First anal plate heptagonal, followed by a second between two interbrachials
First anal plate hexagonal, followed by two interbrachials without a second anal, arms branching from two main trunks by alternate bifurcation
II. Brachials and interbrachials slightly represented in the dorsal cup.
Radials in contact except at the posterior side
a. Radials in contact all around; base pentagonal
Basals directly followed by the radials
b. Radials separated at posterior side by an anal plate; base hexagonal.
Basals separated from radials by accessory pieces
Regarding the terminology employed, special attention should be called to the clear and concise definitions given of the various structural parts. The terms should be universally adopted, and they form
by far the best collection ever proposed. American writers especially will need no appeal to at once use them, not only in order to secure uniformity in nomenclature but to insure precision of description. Heretofore the names of the various plates or groups of ossicles have been used in a rather haphazard way. Not only have different designations been given to the same part but the same title has been repeatedly applied to structures widely separated morphologically.
CHALES R. KEYES.
RECENT BOOKS AND PAMPHLETS.
Annual Report for 1892-93 Geol. Surv. Canada (new series), Vol. VI, 1895. From the Survey.
BOULENGER, G. A.-Catalogue of the Fishes in the British Museum. 2d Ed. Vol. I, London, 1895. From the Trustees of the Museum.
CAYEUX, L.-De l'Existence de nombreux Debris de Spongiaires dans le Précambrian de Bretagne (Première note). Extr. Ann. Soc. Geol. du Nord, T. XXIII, 1895. From the author.
CHAMBERLIN, T. C.-Recent Glacial Studies in Greenland. Extr. Bull. Geol. Soc. Amer., Vol. 6, 1895. From the Soc.
CONN, H. W.-The Outbreak of Typhoid Fever at Wesleyan University. Extr. Conn. State Board of Health for 1894. From the author.
DALL, W. H. AND HARRIS, G. D.-Correlation Papers-Neocene. Bull. U. S. Geol. Surv., No. 84, 1892. From the Dept. of the Interior. GREGORY, H. D.-A Layman's Look at four Miracles. From the author.
LEBOUCQ, H.-Zur Frage nach der Herkunft überzähliger Wirbel;-Einschaltung oder peripherer Zuwachs?
-Die Querfortsätze der Halswirbel in ihrer Beziehung zu Halsrippen. Aus Verhandl. der Anat. Gesell. Mai, 1894.
LINDGREN, W.-Characteristic Features of California Gold-Quartz Veins. Extr. Bull. Geol. Soc. Amer., Vol. 6, 1895. From the Society.
LUCAS, F. A.-The Main Divisions of the Swifts. Extr. The Auk, Vol. VI,
-Additional Characters of the Macropterygidae. Extr. The Auk, Vol. XII,
-The Species of Orangs. Extr. Proceeds. Boston Soc. Nat. Hist., Vol. XXI,
-Notes on the Osteology of the Paridae, Sitta and Chameæ. Extr. Proceeds. U. S. Natl. Mus., Vol. XIII, 1890.
-Notes on the Osteology of the Thrushes, Miminae and Wrens. Extr. Proceeds. U. S. Natl. Mus., 1888.
-Classification of the Macrochires.
Extr. The Auk, Vol. IV, No. 2, 1887.
-Swifts and Humming-birds. Extr. Ibis, 1893. From the author.
LYMAN, B. S.-Folds and Faults in Pennsylvania Anthracite Beds. A Paper read before the Amer. Inst. Mining Engineers, Oct., 1895. From the author. MERRIAM. L. S.-Higher Education in Tennessee. Contributions to American Educational History, No. 16, Washington, 1893.
MERKILL, G. P.-Notes on some Eruptive Rocks from Gallatin, Jefferson and Madison Counties, Montana. Extr. Proceeds. U. S. Natl. Mus., Vol. XVII, 1895. From the author.
MORGAN, T. H.-The Formation of the Embryo of the Frog. Aus. Anat. Anz. Bd. IX, Nr. 23.
-Half Embryos and Whole Embryos from one of the first two Blastomeres of the Frog's Egg. Ibid, Bd. IX, No. 19.
PECKHAM, G. W. & E. C.-Spiders of the Marptusa Group of the Family Attidae. Occasional Papers of the Wisconsin Nat. Hist. Soc., Vol. II, No. 2, 1894. -Spiders of the Homalattus Group of the Family Attidae. Ibid, Vol. II, No. 3, 1895. From the authors.
PETER, K.—Ueber die Bedeutung des Atlas der Amphibien. Aus Anat. Anz. Bd., X, Nr. 18.
-Zur Anatomie von Scolecomorphus kirkii. Aus Berichte der naturf. Gesell. zu Freiburg i. B. Bd. IX, Heft. 3. From the author.
RASPAIL, X.-Durée de l'incubation de l' oeuf du Coucou et de l'éducation du jeune dans le nid. Extr. Mém. Soc. Zool. de France, 1895. From the author. Report of the Geological Survey of Ohio, Vol. VII. Norwalk, Ohio, 1893. ROBERTSON, C.-Flowers and Insects, XII, XIII, XIV. Extr. Bot. Gazette, Vol. XIX.
-Notes on Bees, with descriptions of new species. Trans. Entom. Soc., XXII, 1895. From the author. -Harshberger on the Origin of our Vernal Flora. Vol. 1, 1895.
ROTZELL, W. E.-Some Vestigial Structures in Man. Monthly, June, 1895. From the author.
Extr. Science N. S.,
Seventh Annual Report, 1894, of the Agric. Exper. Station of the Colorado Agric. College, Fort Collins.
SIEBENROCK, F.-Zur Kenntniss des Rumpfskeletes der Scincoiden, Anguiden und Gerrhosauriden. Extr. Ann. K. K. Naturh. Hofmus. Bd., X, 1895. From the author.
SIMPSON, C. T.-Distribution of the Land and Freshwater Mollusks of the West Indian Region, and their evidence with regard to past changes of land and sea. Extr. Proceeds. U. S. Natl. Mus., Vol. XVII. Washington, 1894. From the author.
Sixth Annual Report of the Rhode Island Agric. Exper. Station, 1893, Part II. From C. O. Flagg.
SMITH, E. T.-Bacillus tracheiphilus sp. nov., die Ursache des Verwelkens verschiedener Cucurbitaceen. Aus Centralblatt für Bakterioiogie und Parasitenkunde. Bd. I, 1895.
STEINER, B. C.-History of Education in Maryland. Contributions to American Educational History, No. 19. Washington, 1894.
THILENIUS, G.-Das Os intermedium antebrachii des Menschen. Aus. Morph. Jahrb. V, Bd., Erstes Heft. From the author.
THURSTON, E.-Pearl and Chank Fisheries of the Gulf of Manaar. Bull. No. 1, Madras Gov. Mus. Madras, 1894. From the Museum.
Twelfth Annual Report of the Board of Control of the State Agric. Exper. Station of Amherst, Mass. Boston, 1894.
WEED, W. H. AND L. V. PIRSSON.-Highwood Mountains of Montana. Extr. Bull. Geol., Soc. Am., Vol. 6, 1895. From the Soc.
WINGE, H.-E Museo Lundii. En Samling af Afhandlinger om de i det indre Brasillens Kalkstenshuler af Professor Dr. von Peter Vilhelm Lund udgravede og i den Lundske palaeontologiske afdeling af Kjobenhavds Universitets zoologiske Museum opbevarede Dyre-og Meuneskeknogler. Andet Bind. Forste Halvbind. Kjobenhavn, 1893.
WOODWARD, A. S.-On some Fish Remains of the Genera Portheus and Cladocyclus, from the Rolling Downs Formation (Lower Cretaceous) of Queensland. Extr. Ann. Mag. Nat. Hist. Ser., Vol. XIV, 1894. From the author. WRIGHT, M. O.-Birdcraft. A Field Book of two hundred Song, Game and New York, 1895, Macmillan and Co., Pub. From John Wana
Water Birds. maker's.
ZITTEL, A. VON.-Paleontology and the Biogenetic Law. ence, Vol. VI, 1895.
Extr. Natural Sci
-Grundzüze der Paleontologie (Paleozoologie). München und Leipzig, 1895. From the author
Examples of Rock Differentiation.-Yogo Peak in the Little Belt Mountains, Montana, consists of a stock of massivei gneous rock which breaks up through surrounding horizontal sediments, that have been metamorphosed on their contact with the eruptive. A vertical section through the south face of the mountain caused by a branch of Yogo Creek has affored Weed and Pirsson' and excellent opportunity to study the relations of different phases of the eruptive to one another. The massive rock shows a constant variation and gradation in chemical and mineralogical composition along its east and west axis which is two miles in length. In its eastern portion the rock is a syenite, containing pyroxene, hornblende, biotite, orthoclase, oligoclase, quartz and a few accessories. The pyroxene is a pale green diopside and the hornblende a brownish-green variety. The latter is thought to be paramorphic after the former. In structure the syenite is hypidiomorphic with a 1Edited by Dr. W. S. Bayley, Colby University, Waterville, Me. 'Amer. Journ. Sci., Vol. L, 1895, p. 467.