18 lUdlctiii 4/, United States National Museum. 



then 2 others directly behiud the first pair ; next, on each side, a tooth 

 much larger, pointed, with a conspicuous cusp on the outer side at base, 

 and one or more denticulations beside ; the other teeth larger, similar, but 

 more serrated and more oblique, approaching the lower teeth in form ; 

 median tooth in lower jaw broad, with a small median cusp and 2 or 

 3 larger lateral cusps on each side; the other teeth, 6 on each side, 

 much broader than high, with 4 to 6 sharp, outward-directed cusps, the 

 first cusp longest and bearing a small tooth near its base; these teeth 

 are quite similar and increase slightly in size outward. Tail long, 

 2\ in total length, the caudal fin mostly below it ; anal small, just 

 behind the small dorsal. Sandy gray, Avith some round black spots, 

 larger than the pupil, rather sparsely placed. Pacific coast, from 

 Monterey northward to Washington ; rather common northward, espe- 

 cially in Humboldt Bay. {maculatus, spotted.) 



Notorhynclms maatlaliis, Ayres, Proc. Cal. Ac. Sci., 1856, 1, 72, San Francisco. 

 Nolorhynclms maadahts, Gill, Proc. Ac. Nat. Sci. Pliiia., 18G2, 495, and 1864, 149. 

 Notorhtjnchus borealis. Gill, Proc. Ac. Nat. Sci. Phiia., 1804, 150, Nisqually, Washington. 

 Jleplravchias maculatus, Jordan & Gilbert, Synopsis, 02, 1883. 



12. HEXANCHUS, Kafinesque. 



Hexanchm, Rafinesque, Caratteri, 1810, 14, (tjriseus). 

 Nolidanus, CuviEU, Kegue Animal, Ed. 1, 1817, 128, {ijriseus). 

 Monopterhinus, Blainville, Faune Frangaise, 1828, 77, {■griseiis). 



Two species known, distinguished from all other living sharks except 

 the eel-shaped t7i7((/«^rfo8('/ac/i(f8, by the presence of 6 gill openings. (t,f, 

 six; uyxoc, bend or sinus.) 



a. Median tootli of lower jaw with a sliglit median cusp aud about 3 marginal cusps ; tirst 

 lateral tooth with about C cusps. coniNus, 18. 



aa. Median tooth of lower jaw without median cusp, but with 4 or 5 marginal cusps; first 

 lateral tooth with 8 or 9 cusps. oriseus, 19. 



18. HEXAXCHUS CORINUS, Jordan & Gilbert. 

 (Shovel-nosed Shark.) 



Head large, broad, depressed, and blunt. No median tooth in upper 

 jaw ; about 4 pointed teeth in front of uppsr jaw ; all entire and without 

 basal cusps ; the next 3 teeth with a single strong cusp on the outer 

 margin; others with more cusps, approaching form of lower teeth; me- 

 dian tooth of lower jaw very small, with a small cusp ; lateral teeth 

 with 6 cusps, the first the largest, the others regularly smaller, the 

 median edge in the adult finely serrated. Tail long, twice as long as 

 head, about 3^^ in total length. Pectoral as long as lower jaw from 

 gill opening. Scales on upper edge of tail enlarged. Color almost 

 black, unspotted; a grayish lateral streak. Monterey Bay to Puget 

 Sound, not common. {corinns, northwestern, from corns or aao-iix, the 

 northwest wind.) 



Hexaiiclms corjim.s, Jokpan & Gilbert, Proc. U. S. Nat. Mus., 1880, 352, Neah Bay; and Sequel 

 and Bay of Monterey, California; Synopsis, 62, 1883. (Types, Nos. 37309, 27196.) 



