DISCUSSION OF SPECIES AND THEIB DISTRIBUTION. 283 



This form, originally described from Greenland, has since been found also on the coasl 



of Norway and about Iceland and Spitsbergen, (riinther states, on what authority we are 

 not aware, that it also occurs about Newfoundland. Although characteristically littoral, it 

 has been found at a depth of 250 fathoms. 



BATHYAGONUS, Gilbert. 



Bathyagonus, Gilbert, Prop. U. S. Nat. Mas., xn, 181)0, 89. 



Spinous dorsal developed. Lower jaw the longer. Plates of body spinous. Gill mem- 

 branes united to the isthmus, not forming a fold across it. Teeth well developed on jaws. 

 vomer, and palatines. Pectorals not notched, the upper rays the longest, the lower becom 

 ing regularly shortened. Bones of head thin and yielding, the system of mucous canals 

 Very strongly developed. (Gilbert.) 



This genus is represented by one species, Bathyagonus nigripinnis, Gilbert, obtained by 

 the U. S. Pish Commission steamer Albatross off the coast of California in 477 fathoms. 



XENOCHIRUS, Gilbert. 

 Xenochirus, Gilbert, Proc. U. S. Nat. Mus., xm, lstio, 91. 



Spinous dorsal present. Jaws equal, or the upper the longest. Plates of body spinous. 

 Gill membranes united to the isthmus, the posterior edge sometimes forming a very narrow 

 free fold across the throat. Teeth well developed on jaws, vomer, and palatines. Pectorals 

 divided by a neep notch into two portions, the lower composed of greatly thickened rays, 

 which are. simple and frequently longer than those of the upper lobe. A series of small 

 spines on eyeball above pupil. (Gilbert.) 



This genus, allied to Podothecus, is represented by two species recently taken by the 

 IT. S. Fish Commission steamerA Ibatross off the coast of California — X. triaeanthus, Gilbert, 

 from 77 to 115 fathoms, and X. pentacanthus, Gilbert, in 17S fathoms. 



ASPIDOPHOROIDES, Lacepede. 



Jspidophnroides, Lacepede, Hist. Nat. Poiss., in, 1802, 228,: (type, Aspidophoroides tranquebar, L&c.=Cottus 



monopterygius, Bloeh). 

 Anoplagonua, Gill, Proc. Acad. Nat. Sc. Phila., 1861,167,259. 



Body very long and slender, subterete, octangular, tapering into a very long six-sided 

 tail. Head slender, short, with large eye; mouth small, terminal; jaws and vomer with 

 villiform teeth. Dorsal fin single, without spines, very small, inserted nearly opposite the 

 still smaller anal; other fins small; bony plates of body keeled, without spines; gill-mem- 

 branes broadly united, free from the isthmus. (Jordan and Gilbert.) 



ASPIDOPHOROIDES MONOPTERYGIUS, (Bloch). (Figure 260.) 



Coitus monopterygius, Block, Ausliind. Fische, II, 156, taf. 178. — Richardson, Fauna Bor.-Amer., Fishes, 50. 



Jgonus monopterygius, Schneider, Bloch's Syst. Ichth., 1801, 101. 



Aspidophorus monopterygius, Cuvier and Valenciennes, Hist. Nat. Poiss., iv, 224; VI, 554, pi. clxix.— 



GCxther, Cat. Fish. Brit. Mus., II, 216. 

 Atpidophoroides monopterygiux, Goode and Bean, Araer. Jour. Sci. and Arts, 1877, 477. — Goode, Proc. 



U. S. Nat. Mus., 1880, 480.— Jordan and Gilbert, Bull, xvi, IT. S. Nat. Mus., 725. 



Body slender, elongate, its height 9 in its length. Head triangular, much narrowed 

 anteriorly, its length 5| in that of body; nasal spines very large, diverging, inserted aear 

 tip of snout; no other spines anywhere; eyes very large, longer than snout; supraocular 

 ridges very high; a ridge extending backward from eye along temporal region ; lower jaw- 

 slightly included; caudal peduncle very long and slender, forming about two lift lis the 

 length; breast with flat plates; dorsal ridges high anteriorly, the median line of back from 

 snout to dorsal tin concave. Head 5§; depth 9. 



Radial formula: 1). 5; A. (i; L. hit. ca. 50. 



Color brownish, obscurely banded with darker; pectorals, dorsal, and caudal mottled or 

 barred. 



