[31 J KEVIEW OF THE SCI/ENID.E. 373 



26. ANCYLODON ANCYLODON. 



Lonohurvs ancylodon Blocli &, Schneider, Syst. Ichth., 102, plate 25, 1801 (Surinam). 



Ancylodon jaculidens Cuv. & Val., Hist. Nat. Poiss.,v, 81, 1830 (Cayenne). Giinther, 

 Cat. Fish. Brit. Mns.,ii, 311, 1860 (Surinam; West Indies). Jordan & Gil- 

 bert, Bull. U. S.Nat. Mus., 1882, 111 (Panama). 



Ancylodon airicauda Giinther, Shore Fishes of the Challenger Exp., 1880, 12 (Mouth 

 of Rio de la Plata). 



Habitat. — Both coasts of tropical America ; Surinam ; Panama. 



We have not been able to compare any specimens of this species in 

 good condition, from Surinam, with specimens from Panama. The 

 original types in the museum at Paris are in poor condition, but we did 

 not see, when examining them, any characters by which we could sep- 

 arate them from the specimens collected by Professor Gilbert at Panama. 



Our description is taken chiefly from a specimen in the museum at 

 Cambridge from Kio Grande do Sul. Others from Guiana, Montevideo, 

 and Eio Janeiro are in the same collection. 



The .specimen described by Dr. Giinther as Ancylodon, atricauda dif- 

 fers from our account only in having the head 3 in length and 31 rays 

 in the soft dorsal. It is probably identical with A. ancylodon. 



Genus V.—NEBPvIS. 



Nebris Cuvier & Valenciennes, Hist. Nat. Poiss., v, 149, 1830 (microps). 



Type : Nebris microps Cuv. & Yal. 



This genus is one of the most peculiar in the family. The cavernous 

 structure of the head reaches in this genus its extreme of development, 

 the head being more spongy to the touch than in Stelliferus, Collichthys, 

 or Pachypops. But one species is known. 



We retain the name Nebris, notwithstanding the prior Nebria, as we 

 regard the two names as sufficiently distinct. The number of vertebrae 

 in Nebris is 10 + 14. The genus, therefore, belongs to the Scicminw and 

 not to the Otolithince. 



ANALYSIS OF SPECIES OF NEBRIS. 



a. Body plump, anteriorly tapering to the slender caudal peduncle; profile straight 

 head broad, heavy, extremely spongy above, eye minute, 9^ in head, 2£ in snout, 

 4 in intcrorbital area; 1-J in width of maxillary, which is very broad; mouth very 

 large, oblique; lower jaw projecting, premaxillary anteriorly on a level with the 

 middle of the eye ; maxillary extending to below posterior margin of orbit, 2£ in 

 head ; teeth all minute, those of the lower jaw in a single series; those in upper 

 jaw in a band which widens backwards; tongue large and thick; head entirely 

 scaly ; margin of the preopercle indistinct, with a very wide membranous edge, 

 which is nearly covered with scales; gill-rakers long and slender, 5 + 15; scales 

 small, cycloid; lateral line little arched ; the bases, at least of all the soft fins, 

 densely covered with small scales; dorsal spines feeble, shorter than the dorsal 

 rays; caudal lanceolate; pectorals 1} in head; ventrals If; color silvery, darker 

 above; pectorals dusky on their inner, margin; head 3 in length; depth 4^. D. 

 VIII-1,31; A. 11-13. Scales 18-50 (pores)-18 Microps, 27. 



