242 THE PLAGIOSTOMIA. 



Scymnus {Laemargus) rostratus Muller & Henle, 1841, Plagios., p. 95; Dum^ril, 1865, Elasrn., p. 458. 



Dalatias (Somniosus) rostratus Gray, 1851, Chondroptcrygii, p. 77. 



Dalatias (Somniosus) borealis Gray, 1851, ibid., p. 76. 



Scymnus microcephalus Kroyer, 1853, Danm. fiske, 3, p. 914; Malmgren, 1865, Ocf. Svensk. vet. akad. 



Forh., p. 536; Jensen, 1907, Dan. fiske, p. 315, pi. 29, f. 2. 

 Squalus noruegicus Gray, 1854, Gron. syst., p. 8. 

 Somniosus microcephalus Gill, 1864, Proc. Acad. nat. sci. Phil., p. 264 name only; Jordan & Gilbert, 



1882, Bull. 16, U. S. nat. mus., p. 15; Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 57; 



Jungersen, 1899, Dan. Ingolf cxpcd., 2, pt. 2. 

 Scymnus (Laemargus) brcvipinna Dumeril, 1865, Elasm., p. 456. 

 Laemargus borealis Gunth., 1870, Cat. fishes Brit, mus., 8, p. 426; Helbing, 1904, Nova acta K. Leop.- 



Carol. akad. naturf., 82, pi. 9, f. b and text. 

 Laemargus rostratus GtJNTH., 1870, Cat. fishes Brit, mus., 8, p. 427; Moreau, 1881, Poiss. France, 1, 



p. 363; DoDERLEiN, 1881, Man., 2, p. 102. 

 Laemargus microcephalus Day, 1884, Brit, fishes, 2, p. 320, pi. 162, f. 1. 

 Somniosus carcharias Garman, 1888, Bull. M. C. Z., 17, p. 85, pi. 20. 

 Havkalen Jensen, 1907, Dan. fiske, p. 315. 

 Somniosus rostratus Regan, 1908, Ann. mag. nat. hist., ser. 8, 2, p. 55. 



Snout depressed, blunt, rounded at the end, length from the orbit about one 

 half the distance between the eye and the third gill opening, or a little more than 

 the width of the mouth. Middle of the total length behind the base of the first 

 dorsal at the middle of the free extremity of that fin. Tail from the vent about 

 one third of the total length. Nostrils small, near the end of the snout. Eye 

 small, length of orbit more than one fourth that of snout, equal to distance from 

 the spiracle. Gill openings somewhat narrow, upper angles in front of the 

 pectorals. Origin of first dorsal midway from snout to caudal; base equal in 

 length to snout, or to distance behind the bases of the pectorals, equal to less 

 than one third of the length of the interdorsal space, to about two thirds of the 

 distance between the base of the second dorsal and the caudal, or to the length 

 of the ventral bases. Second dorsal smaller than the first, base equal to about 

 half the distance from the caudal, origin above the ends of the ventral bases. 

 Caudal one fifth of the total, angles not rounded, hind margin of subcaudal 

 deeply and of terminal slightly concave. Intestine of specimen studied with 

 thirty-three turns in the spiral. 



Total length 106, snout to caudal 84, snout to pectorals 252, snout to mouth 

 Sh snout to nostrils 22, and length of caudal 21 inches. 



Blackish brown. 



Specimen described from Provincetown, Mass. 



ECHINORHINIDAE. 



Body massive, subfusiform. Head depressed. Snout broad, tapering, 

 Eyes without a nictitating fold. Mouth crescentic, with labial folds. Teeth 

 sectorial, similar in the two jaws, cusps oblique, notched at each side at the base. 



