DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 283 



This form, originally ilescril)P(l fiom Greeuland, has since been found also on the coast 

 of N^orway aud about Iceland and Spitzbergen. Giinther states, on what authority wc are 

 not awaie, that it also occurs about Newfoimdlaud. Although characteristically littoral, it 

 has beeu found at a depth of 250 fathoms. 



BATHYAGONUS, Gilbert. 

 Bathyagonus, Gilbert, Proe. U. S. Nat. Mus., xu, 1890, 89. 



Spinous dorsal developed. Lower jawthe longer. Plates of body spinous. <;^ill mem- 

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

 vomer, and palatines. Pectorals not notched, the \\\)\)(tv rays the longest, the lower becom- 

 ing regularly shortened. Bones of head thin aud yielding, the system of nuicous canals 

 very strongly developed. (Gilbert.) 



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

 the U. S. Fish Commission steamer Albatross oft' the coast of Galitornia in 4:77 fathoms. 



XENOCHIRUS, Gilbert. 

 Xenochirus, Gilbert, Proc. U. S. Nat. Mas., xiii, 1S90, 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 fre'iuently longer than those of the upper lobe. A series of small 

 sijines on eyeball above pupil. {Gilbert.) 



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

 U. S. Fish Commission steamerAZ&«#ro.ss off" the coast of California — X.triacanthus, Gilbert, 

 from 77 to 145 fathoms, and X. pentacantlnis, Gilbert, in 178 fathoms. 



ASPIDOPHOROIDES, Lacepede. 



Aspidophoroides, LACli;p{;DE, Hist. Nat. Poiss., iii, 1802, 228, : (type, Aspidophoroldes tranqiidiar, La,c.=Cottus 



vionoph-ri/ijiKs, Blocli). 

 Anoplagonus, GihL, Proc. Acad. Nat. Sc. Pliila., 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 flu single, without spines, very small, inserted nearly opposite the 

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

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



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



Cottus mouoptei-i/giiis, Block, Auslaud. Fische, il, 156, taf. 178.— Rick.\rdson, Fauna Bor;-Amor., Fishes, .50. 



Agoutis moiioptcrggiiis, Schneider, Bloch's Syst. Iclith., 1801, 104. 



Aspidophoi-Hs monoptcrggim, CuviER aud Valenciennes, Hist. Nat. Poiss., iv, 224; vi, .5r>4, pi. cLxix.— 



GiJNTHER, Cat. Fish. Brit. Mus., ii, 216. 

 Asjndophoroides nionojileryghis, GooDE and Beax. Araer. Jour. Sci. and Arts, 1877, 477.— Goodk, Proc. 



U. S. Nat. Mus., 1880, 480.— Jordan aud Gilbert, Bull, xvi, U. S. Nat. Mus., 72,"). 



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

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

 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 peduiu'le very long and slender, forming about twotiflJis tlie 

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

 snout to dorsal fin concave. Head 5% ; depth 9. 



Eadial formula: D. 5; A. 0; L. lat. ca. 50. 



Color browuish, obscurely bauded with darker; pectorals, dorsal, and caudal mottled or 

 barred. 



