DISCUSSION OP SPECIES AM) THEIR DISTRIBUTION. 21 



In llic Mediterranean it is found :it considerable depths. In July, is~!». Prof. Giglioli, 

 fishing off Genoa with trawl lines, took 50 individuals at depths of mo to 500 fathoms. 



PRISTIURUS ati. an ■Tiers, Vaii.i.am. (Pigur©20.) 



Priatiurut atlanticus, Vmii.ixi. Exp. Scient, Trav. el Tal., 1888, 59, pi. r, iiu r . I. 



A Pristiurus closely resembling /'. melastomus, Rafinesque, but with its snout some- 

 what more obtuse, its length from the extremity of the upper lip being less than the dis- 

 tance between the labial commissures, while in the other species it is equal or greater. The 



teeth are somewhat stouter, less elongate, ami on their sides are two dent ieiilat inns instead 



of the single one. They also appear to be more numerous — 31 on each side of the upper 

 jaw, in place of lis in /'. mclanostomus. The cutaneous plates, although similar in character 

 and very like in form, have the margin proportionately narrower, and the middle rib more 

 narrow and salient, the lateral teeth being less divergent. The branchial openings decrease 

 in width posteriorly, the last not more than halt' the height of the first; while in /'. melanos 

 tomus it is at least three-fourths. 



The above description is a translation of the description by Vaillant. who, though 

 admitting that the differences taken singly are slight, considered that taken together they 

 impart to the animal a peculiar physiognomy, and that the comparison of a number of 

 specimens of the same size seemed to him to justify the establishment of a new species. 



Vaillant is of the opinion that possibly this form may be that described by Lowe from 

 Madeira, under the name Pristiurus melanostomus. 



A single female, 440 millimeters in length, was taken at a depth of 540 meters off Cape 

 Spartel. from Station VIII of the French expedition. 



Family CETORHINID^. 



Cetorhinidce, Gill, Apt. Fam. Fish.. 1*72. 24.— Jordan and Gilbert, Bull, xvr, U. S. Nat. Mas.. 1883, 30. 



Selachians with very wide gill openings in advance of pectorals, extending from the 

 back nearly to the middle line of the throat. Mouth moderate, the teeth small, numerous, con- 

 ical. Nictitating membrane lacking. A small spiracle between eye and first gill opening. 

 First dorsal large, above space between pectorals and ventrals; second dorsal and anal 

 small. Pectorals and ventrals large. Caudal tin lunate, a pit at its root, the upper lobe 

 considerably the larger. Sides of tail keeled. 



CETORHINUS, Blainville. 



Cilinhiiiiis, Blainville. Bull. Soc. Philoin.. INKS. 121. 

 Selaeke, Civier, Regne Animal, 1829, 390. 

 Polyprosopus, COUCH, Brit. Fish., i, 67-68, pi. xv. 



Fye destitute of membrana nictitans; a small spiracle between the eye and the first 

 gill opening. Gill openings very large. (Jills furnished with gill rakers for filtering pur 

 poses, and consisting of an elastic apparatus of dentine. Teeth small, conical, without 

 dilated bases, and their sides smooth. First dorsal tin above the interspace between the 

 pectoral and ventral; second dorsal and anal small. Caudal with a lower lobe and a pit at 

 its root; sides of the tail keeled. {Day.) 



CETORHINUS MAXIMl'S, Gunner. (Figure 17.) 



Sgwaliu maximus, Gunner. Trondhj. Selsk. skrift.. 1765, in, 33, pi. n, iv, 14, pi. in. — Linn. e is. Syst. Nat., ed. 

 xii, 1766. 400. 



Selaehe maxima, Cuvlbr, Regne Animal. 1829, 391. — Muller ami IIlnll. S. B. Plagiost., 71. — Dumeril, 

 Elasm., 143. — GOnther, eat. Fish. Brit. Mus., vm, 394. — Bocage and Capeixo, Peix. Plagiost., 14.— 

 ' etorhinus maximus, Goode and Bean, Bull. Esses Inst., \i, 29. — Giglioli, Elenco, iss:;. 112. — Jordan 

 andGlLBERT, Bull. XVI. f. S. Nat. Alus.. 31.— DAY, Fish. e. B. A- Ireland, II. 303, pi. ci.vin. fig. 1. 



Squalvs elephas, I.e. Sueur, Journ. Acad. Nat. Sci. Phila., n. 343, fig. — 1>e Kay. Zool. N. V.. fish., 3">7. pi. 

 i.xiii. tig. 208. 



