DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 9 



Ecltinorliinus spiiiosiis, Blaixvii.le, Bull. Sii., 181G, 121. — Faiiuo Frauvaisc, 66. — Bonai'autk, Icon. Faun. 

 Ital., Pescl, HI, pi. c.vx.wiii.— MuLLKR anil Hk.vle, S. B. Plag., 96, pi. i.x.— Yakheli,, Brit. Fi.sh., 2(1 cd., 

 II, 532, fig. ; 3(1 ed., II, .529.— C().sta, Fauna, Nap. Clioud., xvi.— Drjiliiai., Ichtliyologic, i. 4,59.— CiCNTiiKU. 

 Cat. Fish. Brit. Mus., viii, 428.— Goodb and Bf.ax, Bull. Essex Institute, 1877, 31.— Caxe.stkixi, 

 Fauna Itallca, Pesci, 42.— Jordax, lor. HI., 13.— GKiLKii.i, I'esii Italic!, Cat., 53; Eleneo, 1S83, 113.— Day, 

 Fishes Gt. Brit. & Ireland, II, 323, ]d. ci.xii, lig. 2. 



Goniodiis spinosus, AcAS.siz, Poiss. Fo.ss., in, ))1. E. lit;. 13. 



Centrnphoriis sphKixus, S\V.\INS(>X, Fishes, ii, 31.5. 



Sqttalns hrucits, BDXX.YTKRiii-:. Encyidopt^die M(?thodi([ue. 



Erhhiorliiiiiis obemin, Smith. Illustrations nf the Zociloijy of Soutli AfViea. l.s3S-'42. Pisces, pi. i. 



Spiracles bcliiinl the eye, bchiiiil the vertical fritiu the aiiole of tlic mouth. Teeth 

 22~^|- lior.sal fins (tiose together. Each tubercle witli a small spine in the center. Jiiowiiish 

 A'iolet, with or witlioiit dark spots. (Gllniher.) 



A .single iii(li\i(laal lias l)eea observed in tlie western Atlantic. This drifted ashore at 

 Provineetown in December, 1.S7.S ((xoode and Bean, loc. ciL). In tlie ^lediterranean it is rare, 

 and lives at considerabh? depths (Gtiuestrini, Fauna d' Italia, I'esci, p. 42). Ri.sso men- 

 tions one weighing 400 pounds. Day ri^eords the occurrence of .some thirty indiviiluals in 

 British waters since 1828, the largest feet in length; this was a female and contained 

 .seventeen eggs, and was talceu off the P^ddystone in January, ISO!). Since ctiptures in this 

 region have been made at all seasons of the year, it would appear that its breeding place 

 and home is in the noitlieastern Atlantic, and tliat its infie([uent capture is due to its hal)it 

 of living on theoiishore ledges and banks at considerable depths. As the .sjnionyiny shows, 

 it was recorded by Smith from theOape of Good Hope. It may be regarded as i)eculiar to 

 tlie eastern part of tlie .Vtlantic Basin, the Cape Cod sjiecimen being doulitles.s a waif. 



Family SQUALID^E, Gunll-ier. 



Spiiiacidii:, GiiNTnEit, Cat. Fish. Brit. Mus., viir, 1S70, 417-425. — .Ioiidax ;iud (iiLr.i:i;T, Bull, xvi, U. S.Nat. 

 Mus., 1883, 15. 



Selachians with body .somewhat elongate and head depressed; eyes lateral; nictitating 

 membrane tib.sent; inoiitli inferior, rather large, with a deep groove along either side; teeth 

 compressed, varied; nostrils inferior, lateral, near the front margin of the snout; spiracles 

 moderate; gill openings moderate, five on each side and all in front of the pectoral lius; 

 dorsal fins two, each armed with a spine; the first dorsal in front of the pectorals; anal tin 

 lacking; Ciuidal fin with the lower lobe small or obsolete; ventrala far back. 



Of the .seven genera comprising this family only two, Stiudhi-s {^Acaiilhia.f) and (hij- 

 notm [ = Gentnna), are shallow-water forms. Of these, all tlie species are represented in 

 the Mediterranean. The family Spinacidiv is peculiarly characteristic of the Mediterranean 

 fauna, all known species except three, one of which is from the northwestern Atlantic and 

 two are from Jtipaii, occurring in that sea or waters immediately adjacent. SqualuH is the 

 most cosmopolitan of the genera, but does not enter the North Pacific. 



The tleep-sea forms of these little sharks are especially abundant in the great depths 

 outside the entrance to the ^Mediterranean, where an extensive fishery is carried im. 



KEY TO THE GENERA OF Sl'INAClDvE. 



(Adajited from Valllant.) 

 I. Trunk more or less rounded. 



A. Upper teeth bicuspid. 



1. Lower teeth obli(iue, with trencliaut inner edges EtmOPTERUS 



2. Lower teeth tricuspid Ckxtroscyi.i.hm 



B. Vrpper teeth ol)li(|ue, with trenchant inner edges; lower teeth similar. -.[Squ.ai.us. — Shallow water.] 



C. Upper teeth simple, pointed. 



1. Lower teeth more or less erect, triangular ScYMXoiioN 



2. Lower teeth olilirjuc, with treuchant inner edges. 



a. Dorsal spines prominent; " upper teeth triangular," Vaillaut Cextropiioru.s 



b. Dorsal spines liidden; "upper teeth conical," Vaillant Cextro.scy'.mxus 



3. Lower teeth simple, straight Paracentroscylliu.m* 



ir. Trunk rather elevated, trihedral. Teeth erect, conical in upper jaw; triangular, serrated in lower jaw. 



OXYNOTUS 



*A deep-.sea geuns from the Bay of Beugal, described by Aleock in Ann. and Mag. Nat. Hist., 1889, 379. 



