224 Memoir Sears Foundation for Marine Research 



as long as snout in front of mouth, its rear tip about over origin of anal. Second dorsal 

 about as long at base as ist dorsal, and only a very little larger than the latter in area, if at 

 all so, its origin about over midpoint of base of anal. No definite interspace between 2nd 

 dorsal and caudal. Caudal about % of total length, with rounded tip and weakly marked 

 subterminal notch, its lower anterior corner subangular, its axis not appreciably raised 

 above main axis of trunk. No measurable interspace between lower origin of caudal and 

 rear end of base of anal. Anal a nearly equilateral and very obtuse triangle, with nearly 

 straight edges, slightly rounded corners and very short free tip, its origin about under tip 

 of I St dorsal, its base about twice as long as that of 2nd dorsal. Pelvics quadrate, with nearly 

 straight edges and blunted corners, apices broadly rounded, the rear corners more nar- 

 rowly so. Pectoral more than twice as large in area as ist dorsal, brush-shaped, about as 

 broad at base as at tip, with rounded corners, the outer margin nearly straight, but the 

 distal and inner margins moderately convex. 



Color. Uniform grayish brown below as well as above after preservation in alcohol. 



Size. The fact that the claspers of the type specimen (510 mm. long) are only mod- 

 erately developed suggests that this deep-sea shark does not mature until a length of 

 perhaps 550 to 600 mm. is reached. 



Developmental Stages. Presumably A . frofundorum is oviparous, but its eggs have 

 not been identified, although Gudger^" suggests that certain egg cases found on the coast 

 of North Carolina might be of this parentage. If the very small specimen listed above and 

 illustrated in Fig. 38 C actually belongs to this species and not to riveri, as seems probable 

 (from the shortness of its gill openings, its small eyes, as well as from the locality of its 

 capture), frojundorum more closely resembles riveri wlien newly hatched than later 

 in growth, for the length of its caudal is then as great as in riveri (about V3 of total length) 

 and its second dorsal considerably larger than its first dorsal. Furthermore, the snout is 

 considerably longer, relatively, in newborn specimens than in adults of either of the two 

 possible parent species, since it occupies considerably more than one-third of the length 

 of the head, and the anal is actually confluent with the lower edge of the caudal. More 

 interesting still is the great breadth of the basal lines of attachment of the pectorals to the 

 lower sides of the trunk (Fig. 38 C). 



Habits. Nothing is known positively of its habits, but the depth of capture listed 

 above and its uniformly dark coloration above and below suggest a deep-sea habitat. 



Range. A.-profundorum is definitely known only from the continental slope off Dela- 

 ware Bay and from the specimen (or specimens) listed above (p. 222). However, if A. 

 laurussonii from Iceland is identical with it, as the only published account of laurussonii 

 suggests, it is no doubt wide-ranging around the slopes of the northern North Atlantic in 

 the appropriate latitudinal belt." 



12. Proc. biol. Soc. Wash., 25, 19 12: 154. 



13. Profunilorum has also been reported from British Columbia (Halkett, Check List Fish. Canad., 1913; ii?.)- 

 But probably the shark in question was actually A. brunneu; Gilbert, which is rath.er common along the Pacific 

 coast of North America from the Gulf of California northward, in deep water. 



