163 PROCEEDINGS OE THE ACADEMY OF 



BLENNOIDS. 



XVI. Hetekostichus Girard. 



Heterostichus has been recently correctly recognized by Dr. Giinther to be 

 very nearly related to the genus Myxodes ; it is not at all allied to the Trachi- 

 noids. It differs from Myxodes in dentition and several other characters. 



XVII. Hypleurochilus Gill. 



This genus was proposed in the "Catalogue of the Fishes of the Eastern 

 Coast of North America" for the Blennius multifilis of Girard. It is distin- 

 guished from Blennius by its restricted lateral branchial apertures. From 

 Chasmodes and other genera having a similar restriction, it is more remotely 

 separated by its form and other characters. A Blennoid of the Pacific coast 

 described by Girard is nearly allied to the type. 



13. Hypleurochilus gentilis. 



Syn. Blennius gentilis Girard. 



XVIII. Bkosmophycis Gill. 

 Dr. Ayres has described a remarkable Gadoid of California, which has much 

 of the general appearance and the single dorsal of the Brosmii, but has no men- 

 tal barbel, and the ventral fins are represented by single filaments. The 

 species so characterized has been referred to Brosmius, but it is evidently very 

 distinct from that genus, and is the type of a new one. On account of the 

 union of some of the features of Brosmius and Phycis, the name of Bkosmophycis 

 may be given to it. 



14. Brosmophycis marginatus. 



Syn. Brosmius marginatus Ayres. 



On a new typs of AULOSTOMATOIDS, found in Washington Territory. 



BY THEODORE GILL. 



Among the new types of fishes discovered by Dr. Kennerly and other gen- 

 tlemen attached to the North-western Boundary Survey, there is one espe- 

 cially worthy of notice. It belongs to the family of the Aulostomatoids, but 

 is at once distinguished from all the other genera of that family by the com- 

 paratively advanced position of the ventral fins, they being inserted a little 

 behind the bases of the pectoral. The species is evidently quite nearly allied 

 to the spine-bearing members of the family, but may be considered the type 

 of a distinct subfamily. The genus Polypterichlhys, of Bleeker, is more nearly 

 allied to Aulostoma than to the North American genus, and those two genera 

 may be united in one subfamily distinguished from our new genus, and from the 

 recently described Siphonopnathus of Sir John Richardson. The relations of the 

 genus will be discussed more fully in the Report on the Fishes of Western 

 North Amerioa. We here offer a simple synopsis of the family and the diag- 

 nosis of the new genus. The family Aulostomatoids is now restricted to the 

 elongated subcylindrical or subtseniform fishes, with the mouth at the ex- 

 tremity of an elongated tube formed by the nasal and vomerine bones, and 

 the preopercular, interopercular, pterygoid and tympanic ones. The genera 

 Centriscus and Amphisile are only remotely allied to them. 



The family of Aulostomatoids still contains, after the removal of Centriscus 

 and Amphisile, five genera, which may be distributed as follows : 



Subfamily SIPHONOGNATHIN^l Gill. 



SlPHONOGNATHUS Rich. 



Siphonognathus Richardson, Proc. Zoological Society of London, Nov., 1857 ; 

 ib. in Annals and Magazine of Nat. Hist., vol. i. p. 226. 



[July, 



