DISCUSSIOM OF SPECIES AND THEIB DISTRIBUTION. 



I'.'T 



structure. The basal portion of the cephalic appendage is about twice as long as the very 

 small eye. The maxillary is a very slender, narrow bone, extending about as far backward 

 as the intermaxillary. The intermaxillary is slightly protractile and has about lu teeth 

 mi each side, several of which are nearly twice as lame as the rest ; its length is two-fifths 

 of the total without caudal. The mandible is as long as the head without the snout; it has 

 8 teeth on each side, the anterior pair and several other pairs along the shaft of the 

 bone being greatly enlarged. A pair of enlarged teeth on the head of the vomer; several 

 similar teeth on the palatines. Upper pharyngeals armed with several strong teeth. The 

 ej e very small, inconspicuous; its distance from the tip of the snout equals nearly one third 

 its distance from the origin of the soft dorsal. Intestine shorter than length w ithout caudal. 



The soft dorsal has Hi rays, all of which, except the last four, are greatly produced; 

 the second, third,and fourth rays, are the longest; they are nearly twice as long as the 

 body. The anal consists of 11 rays, all of which, except the last three, are much produced. 

 The tin is not quite perfect, yet its anterior rays are longer than the body. The caudal 

 contains 8 rays, of which the four inner ones are divided, while the test are simple. The 

 middle rays are as long as the distance from the tip of the lower jaw to the base of the 

 pectoral. The pectoral is comparatively short and contains 1G simple articulated rays, 

 the longest of which is about one half as long as the head. 



About 9 luminous filaments on each sideof the head, 7 more between the nape and 

 the dorsal, and about 12 on the sides. The filaments are nearly twice as long as the eye. 



Head and body black; caudal cephalic tuft, and most of the lin-rays pale. 



The type of the species is number 39265, taken by the steamer Albatross, {September 

 19, 1887, in N. hit. 39° 27', W. Ion. 71° 15', 127G fathoms. 



Family ONCHOCEPHALID^E. 



Walthceoidei, Gill, Proc. Acail. Nat. Sci. Phila., 1863,89 (diagnosis). 



Malthceoidw, Gill, Arrangemeni Families of Fishes, 1*72, 2 (No. 10); Pr<»c. U. S. X. M., i, 1878, 215-219 (diag- 

 nosis) |i. 231 (key to subfamilies ami genera); v, lss:;, 555 (with elaborate synonymy). 

 Mniiliiihi , Jordan ami Gilbert, Bull, 16, U. ,S. Nat. Man.. 819 (diagnosis ami key i. 

 Onchoeephalidw, Gill, MS. 



l'ediculates with very broad and depressed head, with snout more or less elevated, 

 with trunk short and slender. Mouth not large, subterminal or inferior, the lower jaw 

 included; teeth villiform or cardiform. Gill openings very small above and behind the 

 axils of the pectoral tins. Body and head covered with bony tubercles or spines. Spinous 

 dm sal reduced to a small rostral tentacle, which is retractile into a. cavity under a promi- 

 nent process on forehead; in one genus the rostral tentacle is obsolete; soft dorsal and anal 

 small and short; ventrals well developed; pectoral well developed, its base strongly angled, 

 with long pseudobrachia and •'! actinosts. Branchiostegals 5; no pseudobranchite. 



KEY TO THE SUBFAMILIES AND GENERA. 



I. Body with disk cordiform and caudal portion stout. 



A. Frontal region elevated, and snout more or less produced or attenuated forwards Onchocephalinw 



1. Orbits lateral, teeth on vomer and palatines. 



<i. GUIs 2J Onchocephalus 



b. Gills 2 MALTHOPSIS (See Appendix.) 



II. Body with disl< subcircular or expanded backwards and caudal portion slender; frontal region depressed, 



and snout rounded and obtuse in front Halieutceiiue 



A. Palate edentulous ; rostral tentacle developed; carpus exserted from common membrane. 



1. Disk subcircular; gills 24 pairs. 



a. Month cleft wide, subvertical. Prickles-strong - Hai.ii i i i \ 



//. Mouth small, terminal, Prickles feeble Haliedtella 



_'. Disk subtriangular; mouth small; giBs 2 pairs Dibrancuus 



1'.. I'alate dentigerous; dorsal tin obsolete; rostral tentacle preseni Hun mrtus 



C. Palate and vomer dentigerous; dorsal present; no rostral teutaelc HalIEUTICHTHTS 



198G8— No. 2 32 



