Reviews — Dr. A. FriUch — Palceozoic Fishes. 375 



It is useless, I fear, to discuss the other statement traversed, 

 whether the contours of the Himalayas are due to freshwater 

 denudation ; and we must continue to differ. But I must say- 

 that I still thiuk a personal acquaintance with the Himalayas 

 would give a very different idea from photographs and drawings 

 ot picturesque bits. The splintered precipices referred to by Mr. 

 Howorth are probably due to the effects of frost; and however 

 common in the higher Himalayas, especially where glaciers exist 

 now, or existed formerly, are not, I think, prevalent in the lower 

 valleys. If it be transcendentalism to refer to the denuding action 

 of rain and streams, valleys and ridges which, however gigantic, are 

 the exact counterparts in form of those seen in a bank of clay after 

 exposure to a season's rain, how should the reference of such 

 contours to an unknown agency be fitly designated? 



la IE "V I E "W S. 



I. — Dr. Anton Fritsch on Paleozoic Elasmobranch Fishes. 



" Fauna der Gaskohle und der Kalksteine der Permformation 

 Bohmens." By Dr. Anton Fritsch. Band II. Heft IV. (pp. 93- 

 114, Pis. 806.-90) ; Band III. Heft I. (pp. 1-48, Pis. 91-102). 

 4to. (Prague, 1889-90.) 



THE two latest parts of Dr. Fritsch's well-known work on the 

 Permian Vertebrata of Bohemia form one of the most im- 

 portant contributions to our knowledge of the Paleozoic Elasmo- 

 branchs that have hitherto appeared. A fine Dipnoan skeleton is 

 first described and figured under the name of Cteuodus tardus, as a 

 supplement to the preceding part ; but with the exception of the 

 two pages and one plate devoted to this, the whole of the instalment 

 is occupied with what the author terras the " Ordnung Selachii." 

 Following ancient custom, the Holocephali are included in the group 

 thus designated in the preliminary remarks ; and, for the purposes 

 of the memoir, the Plagiostomi are subdivided into the four " tribes " 

 of Squalides, Xenacanthides, Acanthodides, and Eajides. 



Of the " Squalides," or ordinary Sharks, only a single tooth has 

 yet been found in the Bohemian Gas-coal. This tooth is hybodont 

 in form, and receives the name of Hybodus vestitus. The determine 

 ation, however, falls under the same category as the author's now- 

 abandoned statement concerning the occurrence of a Permian species 

 of Ceratodus ; and it by no means proves the downward range of 

 the Mesozoic genus Hybodus into the Palaeozoic formations. As in 

 the case of the Dipnoi and the Pleuracanths, detached teeth of the 

 hybodont Sharks are worthless for generic determination. 



Of the " Xenacanthides " only the single family of " Xenacanthidse " 

 is recognized ; but why the author should depart from the ordinary 

 system of nomenclature, and not derive the title of this family from 

 its type-genus Pleur acanthus, it is difficult to understand. The three 

 genera Orthacanthus, Pleur acanthus, and Xenacanthus are regarded as 

 quite distinct, and re-defined upon the basis of the new Bohemian 



