8 SPHYNIDiP, KENICEPS. 25 



the iiiitldk' line oftlic b.ick, endiiijj;' in a \nl at the root of the tail ; pec- 

 txjral fins rather lary;e; ventral.s small. Color gray; caudal fin with a 

 conspicuous narrow bl.u-kish cd^c. Xcwibundland to Soutli America; 

 common southward. Size rather small. 



(Squalus (Carcharian) Irrrn'-iiora- KiclKinlsou, 1'. B. A. iii, 2^9: Cun-Jdrias lrrr(v-:iirr(f 

 Giiiither, viii, AW.) 



Family VIII — SPHYRNID^. 



{The Hammer headed Sharhs.) 

 General characters of the Galeorhinida;, but the liead singularly formed, 

 kidney-shaped or " hammer ''-shai^ed from the extension of its sides, the 

 nostrils being anterior- and the eyes on the sides of the ^-hamme]'"; 

 month crescent-shaped, under the '' ha muier '' ; the teeth of both jaws simi- 

 lar, oblique, each with a notch on tiie outside near the base ; no spira- 

 cles; last gill-opening over the pectorals; first dt)rsal an<l ])ectoraLs 

 large, the dorsal n^rer i)ectorals than ventrals ; second dorsal and anal 

 small ; a pit at the root of the caudal ; caudal fin with a single notch 

 towaid its tip, its lower lobe developed. Genera 3 ; species ~> ; inhabiting 

 most seas. Large sharks, known at once by the singul.ir form of the 

 head. {€archariidw, part: group Zygwnina Giiuther, 3S()-.']8;>.) 



'Nostrils ue;ir the eyes. 



((. Nostrils simple, with the frontal grooves rudimeutaiy or ohsolete ; head reni- 

 Ibrni, i's antei-ior and lateral margins otmfliieut, forming a semicircle. 



liKNICEPS, 22. 



(/«. Nostrils with grooves extending in I'ront toward Ihe middle of the hea«l ; 



head truly hammer-shaped Srii ykna, 2:5. 



29.— KENICEPS Gill, 1861. 



Bonnet- h eaded ^Sharls. 



(Gill, Ann. Lye. Nat. Hist. N Y. ISfil, viii, p. 412: type Sqtialiix tibitro L.) 



Head reniform, the anterior and lateral margins continent, forming 

 a regular semicircle, the posterior margins of the sides of the hammer 

 very shoit; nostrils close to the eyes, with the grooves indistinct. 

 (Latin, rena, kidney ; eepx, head.) 

 31. K. tibtni'O (L.) iiiU.—Shord-hmd Shark ; Boinicl Head. 



Body rather slender, not much (;ompressed; head d«^])resse.d, semicir- 

 ctdar in front, reniform, the posterior tree margins short, the lateral mar- 

 gins continuous with the anterior; ])ectorals large; first dorsal liigli, 

 midway between pectorals aiUl venirals ; second dorsal mu(*li smaller, 

 ]H()(luce(l beliind, higher and slioitej' than anal; ventral tins moderate; 

 caudal moderate; mcmth small, crescentic; teeth small, very obli({ue, 

 with a deep notch on the outer margin. Color uniform ashy, paler 



