502 Memoir Sears Foundation for Marine Research 



lower teeth, which are serrate. But it has long been known that all this applies to the Atlan- 

 tic form, and our own comparison of a Japanese specimen with one from the Atlantic coast 

 of the United States shows no significant differences in proportional dimensions, shape or 

 position of fins, teeth, or denticles. 



Dalatias licha (Bonnaterre), 1788 

 Figures 96, 97 



Study Material. Female, 1,470 mm. long, from Georges Bank (Amer. Mus. Nat. 

 Hist., No. 14056") j 4 specimens of about 367 to 1,080 mm., from Nice, France, and an 

 embryo of 245 mm. from the same locality (Harv. Mus. Comp. Zool.) ; also immature 

 male, 1,114 n^"^- long, from Japan (Harv, Mus. Comp. Zool., No. 11 16). 



Distinctive Characters. The serrate margins and triangular shape of its lower teeth 

 mark D. licha off from all other North Atlantic members of its suborder. It is further 

 separated very obviously from the species of Squalus, Centroscy Ilium and Etmopterus by 

 its lack of fin spines, and from Isistius by the position of its first dorsal fin farther forward. 



Figure 96. Dalatias licha, female, 1,470 mm. long, from Georges Bank, Gulf of Maine (Amer. Mus. Nat. 

 Hist., No. 14056). A Head from below. B Left-hand corner of mouth to show labial furrows, about 0.4 

 natural size. C Right-hand nostril, about 1 .2 x. Z) Dermal denticles from side, below first dorsal fin, about 1 2 x. 

 E Dermal denticles from ventral surface of snout, about () n. F First to seventh upper teeth, and median 

 and first to fifth lower teeth from left-hand side, about 1.2 x. G Fourth upper tooth. H Median lower tooth. 

 G-H, about 2.4 X. 



10. Reported five feet one inch (approximately 1,550 mm.) long (Nichols and Firth, Proc. bid. See. Wash., 52, 

 '939= 85) > ''"t low only '147° """• by the system of measurement here employed (p. 61). 



