Fishes of the Western North Atlantic 231 



a little less than ^6 to V? of length of head to 5th gill opening in large specimens, but rela- 

 tively somewhat longer in small (Fig. 40 A), ovate with rounded tip. Eye oval, with fold 

 below it. Spiracle oval, about as long as diameter of eye or longer, its long axis oblique, 

 situated close behind the eye. Second gill opening a little longer than diameter of eye in 

 large specimens, but a little shorter than eye in small. Nostrils far apart and much closer 

 to mouth than to tip of snout, only slightly oblique, the anterior margins with a low, sub- 

 triangular lobe. Mouth rounded in front with nearly straight sides, its height between % 

 and % its width. A well marked labial furrow on upper jaw extending Va to ^4 the dis- 

 tance toward symphysis, the lower furrow very short. 



Teeth minute, extremely numerous, arranged in mosaic j smooth-edged; uppers with 

 3 to 5 triangular cusps, the median much the largest in front part of mouth, but the 

 laterals more nearly equalling it toward corners of mouth; lowers with 3 erect cusps in 

 front of mouth (the median longest) but usually with 4 along its sides, the cusps of the 

 outermost being of nearly equal lengths;' about 6 to 13 series functional, more being so 

 in lower jaw than in upper. 



First dorsal very sloping, about Ve to Vr as high as the length at base, relatively some- 

 what higher in small specimens than in large (see proportional dimensions, p. 229), 

 convex in upper contours, but without definite apex, its free rear margin very short with 

 acute tip, its origin V2 to Vs as far from axil of pectoral as from origin of pelvics, its base 

 between % and Vs as long as the total length, and about i Vs times as long as caudal in 

 large specimens, but only about as long as caudal in small, the rear end of its base termi- 

 nating about over origin of pelvics or a little anterior to the latter. Second dorsal a little 

 higher than i st in small specimens and about 1.7 times that high in large, about twice as long 

 as high, subtriangular, with weakly convex anterior margin, very weakly concave or nearly 

 straight distal margin, broadly rounded apex and very short free rear corner, its origin a 

 little posterior to tips of pelvics, its tip over or a little posterior to tip of anal. Caudal only 

 between Y^ and % of total length, slightly less than V2 as broad as long, with well marked 

 subterminal notch, its posterior outline nearly straight, its lower anterior corner obtuse, 

 subangular. Anal similar to 2nd dorsal, but only about % as long at base and % as high, 

 its origin a little posterior to origin of 2nd dorsal. Pelvics Vs to ^i as long at base as ist 

 dorsal. Pectoral noticeably small, about 1.3 times as long as base of anal, a little more than 

 % as broad as long, with nearly straight distal margin, weakly convex outer margin, 

 rounded corners and broad base. 



Color. Described as uniformly dark brownish gray, darkest on posterior margins of 

 pelvics, dorsals, anal and caudal ; the embryo is described as slate gray.^ 



Size. This is one of the larger deep-water sharks. Specimens so far measured have 

 ranged from 930 mm. to 2,950 mm. (9 feet 8 inches) in length. The length at which it 

 matures is not known. 



4. For recent illustrations of the teeth of a large specimen, see Jacquet (Bull. Inst, oceanogr. Monaco, 36, 1905: 

 pi. 8). 



5. Saemundsson (Vidensk. Medd. naturh. Foren. Kbh., y^, 1922: 197). 



