REPORT OF COMMISSIONER OF FISH AND FISHERIES. [58] 

 191.— QASTROSTOMUS ' Gill & Ryder. 



649. QastroBtomus bairdii Gill & Ryder. B. 



Order U.— OPISTIIOMI. (P) 



Family LXVl.— PTILICHTHYID^.2 (56 6.) 



192.— PTILICHTHYS Beau. (179) 



650. Ptilichthys goodei Bean. A. (594.) 



Family LXVII.— IsTOTACANTHID^. 



193.— NOTACANTHUS Blocli. (180) 



651. Notacanthus chemnitzi Bloch. G. B. (59.t) 



652. Notacanthus phasgaiiorua Goode. B. (595/.) 



653. Notacanthus analis^ Gill. B. 



of the two suspensorial boues, with uiiuute teeth in both jaws, with a short abdomen 

 and long, attenuated tail, branchial apertures narrow and very far behind, dorsal 

 and anal fins continued nearly to the end of the tail, and minute pectoral fins. 



" The mandibular rami are exceedingly narrow and slender, but the jaws are ex- 

 tremely expansible and the skin is correspondingly dilatable, consequently an enor- 

 mous pouch may be developed. Inasmuch as the slenderuess and fragility of the 

 jaws and the absence of raptatorial teeth i)recliide the idea of the species being true 

 fishes of prey, it is probable that they may derive their food from the water which 

 is received into the pouch by a process of selection of the small or minute organisms 

 therein contained." The skin of the pouch has a peculiar velvety appearance, like 

 the wing membrane of a bat. Two species are known, provisionally referred to two 

 genera, Eurypharynx pdecaiwides Vaillant and Gaatrostomus hairdii. Both are from 

 great depths in the sea, the former having been taken by the " Travailleur," in 1882, 

 oif the coast of Morocco. 



{Eurypharyngidce Gill & Ryder, Proc. U. S. Nat. Mus., 1883, 264.) 

 ' Gastrostomus Gill & Ryder. 



Gill & Ryder, Proc. U. S. Nat. Mus., 1883, 271 ; type Gastrostomus bairdii G. & R. 



This genus is supposed to be distinguished from Eurypharynx by the following char- 

 acters : Cranium short, nearly as broad as long ; dentigerous bones almost seven times 

 length of cranium ; jaws with minute, acute, conic teeth depressed inwards, in a very- 

 narrow band ; no enlarged teeth at tip of mandible ; tail with a rayless membrane 

 under its tip. {Fadrrfp, stomach; dTO/na, mouth.) 



{Gastrostomus bairdii Gill »fe Ryder, 1. c., 1883, 271. Gulf Stream, lat. 40°, in deep 

 water.) 



Eurypharynx pelecanoides (Vaillant, Comptes Rendus Acad. Sci. Paris, 1882, 1232) is 

 supposed to differ in having the "cranium prolonged backwards, the dentigerous 

 bones little more than three times as long as the cranium ; faint dentary granulations 

 on both jaws and at the extremitj' of the mandible two hooked teeth; the tail end- 

 ing in a point." It is not unlikely that the two species may prove identical. 



*It is almost certain that Ptilichthys has little relation to the Mastacembelidce. It 

 should probably be regarded as a distinct family, Ptilichthyidce, but whether this fam- 

 ily belongs to the Opisthomi or to the Acanthopteri cannot be ascertained without ex- 

 amination of the skeleton. 



^Xotacanthus analis Gill. Proc. U. S. Nat. Mus. 1883, 255. Gulf Stream, latitude 

 40 at a depth of 548 fathoms. 



