352 PKOCEEDINGS OF UNITED STxVTES NATIONAL MUSEUM. 



DESCKBPTIorV OF A IVK^V SPECIES OF IVOTHDAIVOID SHARK (IIEX- 



AIVCHUS CoklNUS), FROM THE PACIFIC COAST OF THE UIVITEO 



STATES. 



By ©AVIO S. JOKDAN aaad CBIARLES H. CiSLBERT. 



Hexanchus corinus, sp. nov. 



Head large, broad, depressed and very blunt anteriorly ; tlie length 

 of snout from front of mouth little more than half the interorbital space 

 and rather less than the distance from the front of the mouth to angle 

 of the mouth. 



Ko median tooth in upper jaw. Two sharp, slender teeth in front of 

 upper jaw, behind which is a row of four others similar but a little larger ; 

 the two outer larger than the inner, all without basal cusps. Behi: d 

 these are four others similar and still a little larger. These are di- 

 rected backward, and should not be considered as functional teeth. 



The first of the large teeth in the upi^er jaw is larger than the succeed- 

 ing teeth. It has a sharp point hooked outward, and a single strong 

 cusp on its outer margin, its inner edge not serrate. The second 

 tooth, on both sides, has the basal cusp obsolete. The third tooth is 

 like the first, but a little smaller. The fourth tooth is slightly serrated 

 on the inner margin, and has two strong cusps on the outer at base. 

 The fifth and sixth are similar to the fourth, but more strongly serrate on 

 the inner margin. The seventh, eighth, and ninth are small, and the 

 luimber of cusps is increased, so that they approach the form of the 

 teeth of the lower jaw. 



The median tooth of the lower jaw is very small, with a slight me- 

 dian cusp and three cusps on the outer margin, the uppermost the 

 largest. The first lateral tooth has six cusps ; the first the largest, the 

 others progressively decreasing; the long edge of the first cusp is finely 

 serrated, but has no basal cusp. The second, third, fourth, and fifth 

 teeth are precisely similar in size and form to the first. The sixth and 

 seventh are somewhat smaller. In the smaller specimen, from Soquel, 

 the inner edge of the teeth is not serrated. Behind the large teeth in 

 each jaw is the usual series of small blunt teeth, which in this species 

 are little developed. 



Nostrils near the tip of the snout. Furrow of skin at angle of mouth 

 reaching half way from the angle of the mouth to the gill-opening. Eyes 

 large, § the length of the snout. Spiracles small, far behind the eyes. 

 Gill-openings 6. Pectoral moderate, as long as from first gill-opening to 

 tip of lower jaw. Ventrals small, reaching i)ast front of the small dorsal. 

 Dorsal a little higher than anal, and terminating over the middle of the 

 latter fin. Tail long, twice as long as head, a little less than ^ the 

 total length, little bent upward : its basal lobe little developed ; the scales 

 on its upper edge somewhat enlarged. 



