118 CLASS XIV. 



Family XXI. Heteropygii. Upper margin of mouth formed 

 principally by the intermaxillary bone. Teeth acute, small in jaws 

 and palate, none in vomer and tongue. Body scaly. Head naked. 

 Dorsal fin remote, opposite to anal. Vent in front of pectoral fins 

 behind gills. Ventral fins small. Aperture of gills small. Pseu- 

 dobranchise none. Swimming-bladder fm'nished with a duct to the 

 oesophagus. 



Amhlyo^psis Dekay. (Characters of family.) Branchiostegous 

 membrane with six rays. Two very small black points at the sides 

 of head, instead of eyes. 



Sp. Amhhjo]psis spelceus. A small fish from the United States of America, 

 first described by Dekay in the Fauna of New York, with which I 

 am not acquainted. It lives in a subterranean grotto in Kentucky, and 

 is — like other animals removed from the light — whitish or colourless. 

 Dekat placed this genus with the SUuroidei, from which however it differs 

 by the scaly body. There are two small pyloric appendages ; nevertheless, 

 I think that this genus is best placed in the neighbourhood of the Cyprino- 

 dontes. It differs from all the other Malacopterygii ahdominales in the 

 position of the vent. See Wyman Descr. of a Blind Fish, &c. Annals 

 of Nat. Hist. XII. 1843, pp. 288, 299 (from Silliman's American Journal, 

 1843), and Tellkampf in Muelleu's Archiv, 1844, s. 381 — 394, Taf, ix. 



II. Malacopterygii apodes. Ventral fins none. Body elongate, 

 skin thick and soft, with scales often small hidden in the skin. 

 Swimming-bladder in most, either furnished with a duct or closed. 



Family XXII. Gymnotini. Pectoral belt affixed to cranium. 

 Upper margin of mouth formed in the middle by the intermaxillary 

 bones, at the sides by the small supramaxillaries. Teeth mostly 

 subulate or conical, small, in the intermaxillary bone and in lower 

 jaw ; some similar teeth in the fore part of vomer and in the synv 

 physis of lower jaw. Branchial aperture in front of pectoral fins. 

 Ovaries famished with duct. Swimming bladder open by a duct 

 into the oesophagus, double in many. Pyloric appendages. 



* Dorsal fin. 



Gymnarchns Cuv. Dorsal fin longitudinal. Tail towards the 

 finless apex acuminate. Head naked; body scaly. 



Sp. Gymnarchus niloticus Gov. R. Ani., 2e Mit. PI. 13, fig. 3. A represen- 

 tation of the skeleton is given by J. Htrtl Denkschr. der mctthem. natur. 

 Classe der Kaiserl. Akad. der Wissenscfi. zu Wien, 1856. Compare FoERG 

 Remarques surl'appareil pulmonaire d'U Gymnarchus niloticus, Ann. des Sc. 

 not. 36 S6r[e, xx. 1853, PP- ^Sh 162, PI. 5, and Hybtl, 1. 1. 



* * Dorsal fin none. 



