41 



The two genera above mentioned have recently been studied 

 by Berg ('04). 



The following analytical table will serve to exhibit the re- 

 lations of the three genera here recognized, the characters of 

 the Asiatic genus being derived by us from the papers of Berg, 

 Mkolsky, and Kessler. 



A. Caudal peduncle shortened and laterally compressed as in 

 Acipenser, the rows of scutes not meeting above and be- 

 low to form a complete armor; mouth as in Acipenser, 

 the lips two-lobed* and without clusters of papilla- ; gill- 

 rakers lance-shaped as in Acipenser] air-bladder small or 

 rudimentaryf ; ribs numerous.^ 



Pseudoscaphirhynchus Nikolsky. 



AA. Caudal peduncle lengthened, depressed, broader than 

 deep, and completely armored; lips four-lobed, each lip 

 bearing four clusters of flattened tubercle-like lappets ; 

 gill-rakers fan-shaped, two-, three-, four-, or five-pointed 

 on the lower half of the arch. 

 b. Ribs twenty or twenty-one ; gill-rakers two- or three- 

 pointed ; belly and breast naked ; air-bladder 8 in 

 length of head and body. 



Parascaphirhynchus, gen. now 



bb. Ribs ten or eleven ; gill-rakers two-, three-, four-, or tive- 

 pointed ; belly and breast wholly covered with subrhom- 

 bic plates ; air-bladder 5 in length of head and body. 



Scaphirhynchus Beckel. 



Issued May 15, 1905. 



*See Berg, Zool. Anz., XXVII., 22, 1904, p. 667; also Kessler's fiugrea 

 of P. kaufmanni and hermanni, Aralo-Caspian Exped., IV., 1877, 1- ig. 



25 and 26. 

 |One twenty-seventh of length of head and body in P . fedtschenkoi. 



JTwenty-four or twenty-five in P. fedtschenko 



