2580 Bulletin ^7, United States National Museum. 



over cavity containing nostrils to a prominent point at side of and slightly 

 posterior to tip of suout; barbel j as long as eye. lutcrorbital space 

 almost twice diameter of eye, equal to length of upper jaw ; preoperculum 

 crenulate; upper jaw extending to vertical througli posterior margin of 

 pupil, its length equaling \ that of head without snout; mandible 

 extending behind vertical through posterior margin of orbit, its length 3 

 times in distance from tip of snout to origin of iirst dorsal. Teeth in vil- 

 liform bands on intermaxillary and mandible, the maudibulary series 

 uniserial in about the second half of its length. First ray of dorsal very 

 short, second compressed anteriorly and serrated, with slender teeth 

 closely appressed and bent upward, its length equaling length of head 

 and greater than height of body ; this fin seated upon a hump-like eleva- 

 tion of the back, its base as long as snout; second dorsal beginning over 

 tenth or twelfth anal ray, and at a distance from end of first dorsal equal 

 to length of head without suout ; vent located not far behind vertical from 

 end of first dorsal. Scales 22 to 24 in a transverse series (the position of 

 the lateral line can not be determined, but there appear to be 4 above it) ; 

 scales oval, membranaceous, showing several parallel ridges composed of 

 small spines. Gill membrane very deeply cleft and attached to the 

 isthmus ; gill rakers short and stout, about 11 below the angle on the first 

 arch. (Goode & Bean.) Gulf Stream, in deep water, (carajjintis, formed 

 as in Carapus.) 



Ooryphcenoides carapinus, Goode & Bean, Bull. Mua. Comp. Zool., x, No. 5, 195, 1883, 

 Gulf Stream, Lat. 41^ 24' 45" N., Long. 65° 35' 30" W., in 1,242 fathoms (Type in M. 

 C. Z. Coll. Blake); Gunther, Cballengor Report, Deep-Sea Fishes, xxn, 139, 1887; 

 Goode dc Bean, Oceanic Ichtliyology, 404, fig. 339, 1896. 



1005. HYMENOCEPHALUS, Giglioli. 



Hymenocephalus, Giglioli, Pelages, Genoa, 228, 1884 (italieus) . 



Mystaconurus, Gunthee, Challenger Eeport, Deep-Sea Fishes, xxii, 124. 1887 (italieus). 



This genus is closely allied to Coryphoinoides, differing in the smooth 

 dorsal spine, and the membranaceous skull. First dorsal broad, placed 

 far forward over base of pectoral; second dorsal and anal origins nearly 

 opposite, and separated by a considerable space from the vertical from the 

 end of first dorsal; vent far from ventrals. Head large, naked, soft, and 

 cavernous ; snout abrupt, perpendicular, or parab(dic ; mouth lateral, wide. 

 Eye very large, orbital margin forming part of profile of head. Barbel 

 long. Pectoral rather narrow (10 to 16 rays). Scales thin, deciduous, 

 with fine short spines. Under parts in advance of ventral wholly or 

 partly naked. Deep seas. Remarkable for the papery structure of the 

 bones of the head, (u/r?)?', membrane; KE*!>aXr),heii(\..) 



2956. HYMENOCEPHALUS CAVEBNOSUS (Goode & Bean). 



Head about 6 in total length; depth 7. D. II, 10-133; A. 27 rays, in a 

 space equal to length of head. Body stoutish, the bones of head very 

 soft and cavernous, spongy, in many places without muscular covering; 

 interorbital area doubly concave, with a spinous medial ridge, its greatest 



