On the Characters of Cartilaginous Fishes. 33 



of the neck. From 7 to 9 femoral pores in the last row, and 4 in the first. 

 Length, from 14 to 16 inches. 



P. sub-viridis. Scales of transverse rows smallest towards the dorsal line, 

 where they are of a somewhat circular form ; on the sides they are larger, 

 and inclined to a triangular shape, with elevated discs, and each faintly ca- 

 rinated. Colour above, blue green, the back freely variegated with faint 

 longitudinal short whitish streaks, beneath greenish brown. Length 1 inches. 



There is a considerable resemblance between the two first 

 species of this section, but they will easily be distinguished 

 by a regard to the character of the scales. In montanus they 

 are carinated ; whilst in fasciatus they have elevated discs, 

 without any appearance of carina?. 



Art. VII. On the generic characters of Cartilaginous Fishes, with 

 Descriptions of new genera. By Professor J. Muller and Dr. 

 Henle. 



The confusion which still exists in the natural history of car- 

 tilaginous fishes, may be attributed to the generally imperfect 

 descriptions which have been given of the species, and also 

 to the circumstance of the most important generic characters 

 having been, in many instances, either overlooked or not suffi- 

 ciently appreciated. In searching for characters by which the 

 genera and species might be distinguished with more accura- 

 cy than had been previously done, we found ourselves com- 

 pelled to enlarge the number of genera and subgenera hitherto 

 established ; but, at the same time, we most carefully avoided 

 making these additions, unless very essential differences ren- 

 dered their establishment necessary. Such are, in the order of 

 Sharks, the system of dentition, the form of the nose, of the 

 mouth, and lips, and of the caudal fin; the existence or want of 

 the eyelid, {membrana nictitans) spiracles, and of the small de- 

 pression or dimple on the root of the tail ; the situation of the 

 branchial openings, and of the dorsal fins ; and in the order of 

 Skates, the form of the nasal valve, and of the membranaceous 

 curtain behind the teeth, {velum maxillare) the number and si- 



* We regard this communication as an extremely valuable one, from the 

 veiy extensive materials to which the authors have had access, in drawing 

 up the arrangement of so highly interesting an order of vertebrate animals 

 as the Cartilaginous Fishes. Prof. Muller and Dr. Henle have just return- 

 ed to Berlin, after spending some months in this country ; during which 

 they visited the different Museums of Natural History, besides having the 

 use of Dr. Andrew Smith's extensive collection of Sharks from the Cape ; 

 the result of their investigations, up to the present time, is embodied in this 

 paper. The Article is in Dr. Henle's own English, with a few revisions. Ed, 



Vol. III.— No. 13. n. s. d 



