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Their increase in number has not been due to subdivision of primitive teeth as supposed by Kükenthal, nor is it a survival of primitive conditions, as supposed by Ameghino, but it is probably a repetition of similar structures due to an extension of the dental groove and dental lamina, following the gradual elongation of the maxillary and premaxillary bones, proceeding contemporaneously with degeneracy of the teeth themselves.-E. D. COPE.

Eozoon canadense.

In recent numbers of the Geological Magazine, Dr. Dawson cites the evidence to date for the animal nature of Eozoon. Briefly summarized, the facts are these: (1) The rocks of the Grenville series, where the fossil in question occurs most abundantly, belong to a sedimentary formation. (2) They form a great calcareous system comparable with the metamorphosed Paleozoic calcareous beds of organic origin in petrological and chemical character. (3) New material showing more plainly the structure of the canal systems and tubes, evidences a definite plan of macroscopical structure. (4) Late discoveries of Archaeospherinae and other objects supposed to be organic in pre-Cambrian rocks in Canada and in Europe afford, to some extent, corroborative evidence in favor of Eozoon. (Geol. Mag. 1895.)

Thickness of the Coal Measures.-According to Mr. J. C. Branner, the total thickness of the Coal Measures (Pennsylvanian) sediments in Arkansas is greater than that of the sediments of the same age in other parts of the country or of the world. He gives the following table of comparison: Arkansas, 23,780 feet; Nova Scotia, 16,000 feet; Utah and Nevada, 16,650 (?) feet: Indian Territory, 10,000 feet. Mr. Branner finds a reason for the great thickness in the drainage of the Continent during Carboniferous times. "The rocks of this series in Arkansas afford fossil evidence that this part of the Continent was probably not much above tide level. The drainage from near the Catskill Mountains in New York flowed south and west. The eastern limit of the basin was somewhere near the Archean belt from New England to central Alabama. This Appalachian water shed crossed the present channel of the Missouri from Central Alabama to the Ouachita uplift, and the drainage flowed westward through what is now the Arkansas Valley, between the Ozark Island on the north and the Arkansas Island on the south." (Amer. Journ. Sci., Sept., 1896.)

Geological News.-PALEOZOIC.-An accumulation of fresh material from the Ichthyologic fauna of the Cleveland Shales, Loraine County, Ohio, has enabled Mr. C. R. Eastman to determine the rela

tions of certain body-plates in the Dinichthyids. These are the median ventral plates of Titanichthys, and a postero-dorso-lateral of Dinichthys. The author further states that "every plate present in the body armor of Coccosteus has its representative in Dinichthys, and that the conditions of overlap and underlap are the same in both forms. (Amer. Journ. Sci., July, 1896.)

CENOZOIC.-Mr. H. W. Fairbanks states that the Lower Cretaceous age is represented in Santa Barbara County, California, by the Knoxville beds, containing the characteristic Aucella fossils. This is the southern point at which the genus Aucella has been found in California. (Bull. Dept. Geol. Univ. Calif., Vol. II, 1896.)

The skull of Orycteropus gaudryi (Ant-Bear or Aard-Vark) from the Lower Pliocene of Samos, described by C. W. Andrews, indicates an animal about one-fifth less than the living species. The close resemblance between the fossil and recent forms is remarkable. Dr. Forsyth Major has pointed out that the former distribution of the genus indicates its northern origin, and that it spread into Africa along with the rest of the Pliocene Mammalia with which it has been found. (Proceeds. Zool. Soc. London, 1896.)

In discussing the geographical distribution of the known Castoroid species, Mr. Merriam notes that the American Castorinae seem to reach their maximum development at or before the beginning of Pliocene time, while the culmination of the Eurasia group appears to occur in the Pliocene. This apparent earlier culmination of the American Castorinae, together with the earlier extinction of certain forms in this country, seem to point to an American rather than to the European origin of the family. (Bull. Dept. Geol. Univ. Calif., 1896.)

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According to Dr. Shufeldt, Harpagornis, the fossil bird recently found in New Zealand, represents a more or less aquiline type, that might easily have been the common ancestor to a number of genera existing modern eagles, as, for example, Haliaetus, Aquila and Thalassaetus. A natural scheme of classification would place it between the genera Aquila and Thalassaetus. (Trans. New Zeal. Inst. [1895], 1896.)

ZOOLOGY.

Fishes in isolated pools.-The occurrence of fishes in pools which have no communication with running streams or large bodies of water has been often noticed, and the explanation of their origin and persistence in such places is in some cases not satisfactory.

In collecting during this month (September) in Camden county, New Jersey, I made the following observations. I fished near Winslow, a pool of about twenty-five feet in diameter, and two feet in depth, with a muddy bottom and a few Nymphæas growing in it. It is distant about a quarter of a mile from an insignificant ditch with a little running water, and is surrounded by higher and sandy ground, offering no possible communication with the ditch. A half mile distant and still more inaccessible is a running stream. From this pool I caught large numbers of the following fishes. Umbra pygmæa, Apomotis obesus and Acantharchus pomotis. The Acantharchi were small, while the others were fully grown.

A quarter of a mile distant from this pool, and at an equal distance from the ditch above mentioned, and not connected with it by any depression of the surface, is another pool of about thirty feet in diameter. The water reaches a depth of three feet in a limited portion of it, and Nymphæas are more numerous, together with Utricularia, etc. Here I obtained the following fishes in considerable numbers. Umbra pygmæa, Amiurus prosthistius, Esox vermiculatus, Aphododerus sayanus, Apomotis obesus, Mesogonistius chaetodon, Acantharchus pomotis. Many of these were fully grown. The turtle Chrysemys picta was also abun.dant.

The mud in the first mentioned pool was light colored, and all the fishes were remarkable for the extreme paleness of their tints. The second pool is situated in better soil and its mud contains much decomposing vegetable matter, and is consequently black. The fishes were all deeply pigmented, including the three species found in the other pool, from which they could be distinguished at a glance. The smaller pool was said to have been dried up during the past summer.

Seven additional specimens of the Amiurus prosthistius Cope enable me to verify the characters already given (Proceeds. Acad. Nat. Sci., Philada., 1883, 133), from an examination of four from the Batstow River, New Jersey. In five of the new specimens where I counted the anal rays, they number 26. Prof. Jordan has recently attempted to

identify the species with his A. erebennus in The Fishes of North and Middle America, 1896, p. 139. From Jordan's descriptions it is evident that the A. prosthistius is nearer to the A. natalis than to the A. erebennus. The spines are not elongated as in the former, nor is the head long and narrowed forward, but it is short and wide; it enters the length (without caudal) 3 times and not four times. The mouth is relatively wider in the A. prosthistius, being .66 of the head-length, and not .5 of it as in A. erebennus. The inferior barbels are white in the former, while one may suppose they are black in the A. erebennus from Jordan's description. The supraoccipital spine is widely separated from the dorsal spine. In the specimens from Winslow the anal fin is relatively longer than in those from Batstow; in the former it. enters the length (without caudal fin) very little over three times (3.2), while in the latter it enters from 3.5 times in one, to 3.66 in two, and 3.85 in another. The length of the anal rays is .66 of that of the head in the Winslow specimens, and .5 of the head in the Batstow speciThe latter are of larger size.-E. D. COPE.

mens.

On the Mud Minnow (Umbra pygmaea) as an air breather. -In the autumn of 1895, I tried to keep a few fishes alive in a small aquarium, viz., a glass jar holding about a gallon. This was filled with well water and some water plants placed in it which grew well. Various fish were placed in it from time to time but all without exception died in less than six hours except a Mud Minnow (Umbra pygmæa) This came to the top at frequent intervals, on each occasion emitting bubbles of air and presumably gulping more down, making considerable noise in so doing. On being placed in well aerated water six weeks or more later, this habit ceased.

The other fishes which were placed in the jar, Catfishes, Minnows, Sunfish, and Suckers would come at once to the top gasping for air, and died in an hour or two.

I have placed other of these fish-Umbra pygmæa, in well water and they acted the same way, coming to the top at frequent intervals and "bubbling" each time.

I have never found any of these fish dead in dried up pools, though I have carefully looked for them, presumably their ability to use air for respiration saves them.-C. S. BRIMLEY.

The Peritoneal Epithelium in Amphibia.-In a recent study of the peritoneal ephithelium in Amphibia the following points were noted. The species examined were Necturus maculatus, Amblystoma punctatum, Desmognathus fusca and Diemyctylus viridescens. All the

specimens of Necturus, Desmognathus and Diemyctylus were taken from January to April and none were examined after spawning. Specimens of Amblystoma were studied shortly before and immediately after ovulation, and in August and December. In all the species cilia were found only in the adult female. They occurred constantly upon the hepatic ligament, the ventral wall of the body cavity, the membranes near the mouths of the oviducts and upon the serosa of the liver. In Amblystoma cilia were also found upon the mesoarium and the membranes supporting the oviducts. Some of the adult female Necturi possessed cilia also upon the cephalic part of the dorsal wall of the body cavity. The ciliated cells occured either singly or in groups. They were most numerous near the mouths of the oviducts. It was found that the direction of the current produced by the cilia was towards and into the mouths of the oviducts. This and the fact that cilia are present upon the peritoneum of the adult female only would seem to strengthen the theory that the ova when set free in the body cavity are propelled by means of cilia into the oviducts.-ISABELLA M. GREEN.

The Penial Structure of the Sauria.-In the Proceedings of the Philadelphia Academy for August and September I have published a paper on this subject, which gives the results of an investigation into the anatomy of the hemipenes of lizards. Very little attention has been given to the subject hitherto, and our knowledge up to 18561 is thus summarized by Stannius: "A duplication or bifurcation of each organ is present in Lacerta and in Platydactylus guttatus. The copulatory organs of the Chamæleonidæ are distinguished by their shortness. In various Varanide which have been investigated the internal cavity (external when protruded) has transverse concentric folds. A fissure interrupts these folds so that they are not complete annuli. The extremity is acuminate and expands at the base, forming a kind of glans."

In 1870 J. E. Gray describes and figure this organ of Varanus heraldicus, giving the best illustration that I know of. In 1886 Wiedersheim (Lehrbuch der Vergl Anat. Wirbelth.) describes and figures this organ in Lacerta. Besides these references I know of nothing later.

As was to have been anticipated, I have found these organs to correspond with the rest of the structure, and to furnish invaluable aids to the determination of affinities among the Sauria. Reference to them

1 Zootomie der Amphibien, p. 266.

2 Annals Magaz. Nat. Hist., 1870, VII, p. 283.

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