156 THE PLAGIOSTOMIA. 



oculonarial expansion at right angles to body 

 a narial groove in front of the snout 

 outer edge of hammer rounded 



front of snout broadly rounded . . tudes (page 159) 

 no narial groove 



outer edges of hammer nearly straight 



front of snout nearly straight . mokarran (page 160) 

 Head heart shaped 



eyes and nostrils not widely separated 



oculonarial expansion narrow .... tiburo (page 160) 



Cestracion blochii. 



Squalus zygaena Bloch, 1785, Ausl. fische, 1, p. 29, pi. 117; Schneider, 1801, Bloch Ichth., p. 131. 

 Zygacna blochii Cuv., 1817, Reg. anim., 2, p. 127; Valenciennes, 1822, Mem. Mus. hist, nat., 9, p. 227, 



pi. 12, f. 2; Bennett, 1830, Mem. Raffles, p. 004; J. E. Cantor, 1837, Quart, med. journ. Calcutta, 



pi. 1-4; Trans. Med. & phys. soc, 8, pt. 2, p. cexi, App.; Gunth., 1870, Cat. fishes Brit, mus., 8, 



p. 380. 

 Zygaena laticeps J. E. Cantor, 1837, Quart, med. journ. Calcutta, pi. 1-4; Swains., 1838, Class., 1, 



p. 134, f. 11; 1839, 2, p. 318; Yarrell, 1839, Brit, fishes, suppl., p. 64, f. 3, 4. 

 Sphyrna blochii Muller & Henle, 1841, Plagios., p. 54, 199; Bleeker, 1849, Verh. Bat. gen., 22, p. 6; 



T. Cantor, 1849, Malay fishes, p. 1386; Bleeker. 1852, Verh. Bat. gen., 24, Plagios., p. 41, pi. 3, f. 7. 

 Pusphyra blochii Gill, 1861, Ann. N. Y. lye, 7, p. 412 (name). 

 Cestracion blochii Dumeril, 1865, Elasm., p. 383. 



Oculonarial expansions very slender, making the width of the head in 

 small specimens little less than half the total length, nearly at right angles with 

 the longitudinal axis, slightly oblique on the hind margin, broadly rounded on the 

 outer edge, nearly straight between eye and nostril. Snout broadly rounded 

 between the nostrils. Nostrils much nearer to the mouth than to the eyes, with 

 a deep groove to the orbits and for a short distance toward the middle of the 

 snout. Width of mouth nearly equal to the distance from the end of the snout; 

 labial folds rudimentary. Teeth very oblique, deeply notched on the outer edge 

 in §5 rows; median teeth of upper jaw small, more erect, indented on both edges. 

 Orbits separated by less than their width from the nostrils. Gill openings 

 much wider than the orbits. Pectorals moderate, hind margin oblique, concave 

 near the inner angle. Origin of the dorsal above the end of the pectoral base, 

 length of base about half of the interdorsal space, or two thirds of the height of 

 the fin, end not quite reaching a vertical from the ventrals. Second dorsal about 

 half as large as the anal, origin above the middle of the anal base, ends of both 

 base and fin extending a little farther back than those of the anal. Anal deeply 



