6o4 THE AMKRIlAX XATi-RALlST. [V.,l. XXXVIII. 



In the Transactions of the American Philosophical Society (XX, 

 1901) Dr. O. P. Hay gives a valuable table showing the chronologi 

 cal distribution of the genera of elasmobranchs. He calls attention 

 to one remarkable fact. While many genera and species (Clado- 

 selachidce, Acanthoessidai, Psammodontidae, Pleuracanthidae, Clado- 

 dontidae, etc.) occur in the Devonian and Carboniferous ages, only 

 three genera remain in the Permian and but four in the Triassic. 

 All these are Heterodontidse, the successors or descendants of the 

 OrodontidEe of the Carboniferous. In the Jurassic, numerous fami- 

 lies with many genera appear, and through these from Heterodontid 

 stock the modern sharks seem to have sprung. Apparently the Pale- 

 ozoic families, except the Orodontida;, have no modern descendants. 



In the Bulletin of the Museum of Comparative Zoology (XLI, 1904) 

 Samuel Carman gives an elaborate and excellent account with beau- 

 tiful plates of the anatomy of the long-nosed Chimaera of Japan, Rhi- 

 nochimcera pacifica (Mitsukuri). In connection with the study of this 

 species, he has given a general account of the living chimaroid 

 fishes, with figures of some of them. On grounds of priority, Mr. 

 Carman substitutes the name Chismopnea Rafinesque, 18 15, for the 

 later name Holocephala of Muller (1834). 



In the Geological Magazine (IX, 1902) Dr. Charles R. Eastman 

 founds a new family of fossil sharks, Peripristidee, on the genus 

 Peripristis (Pristodus). 



In the American Geologist (XXX, 1902) Dr. Bashford Dean gives 

 illustration of a startlingly perfect preservation of the muscular fibre 

 of a shark, Cladoselache fyleri, in the Cleveland shales. This was an 

 estuary deposit originally of fine mud, in which the fish remains 

 became phosphatized. 



In the Proceedings of the Academy of Natural Sciences of Philadel- 

 phia (1903) Dr. Carl H. Eigenmann and Clarence H. Kennedy dis- 

 cuss a large collection of river fishes, made in Paraguay by Prof. J. 

 D. Anisits of the Paraguay National University. One hundred and 

 nme species are noted, many of them new, and the paper is followed 

 by a useful biography. A feature of special convenience is a synop- 

 sis of the genera of Cichlida, 25 in number, Biotodoma and Biotoe- 

 cus being new names. 



In the Annotationes Zoologicce faponenses of the Imperial University 

 of Tokyo Dr. Bashford Dean gives a study of the development of 

 the egg of the Japanese shark, Heterodontus japonicus. He finds 

 good evidence of the existence of holoblastic cleavage. 



