454 THE PLAGIOSTOMIA. 



Ceratobatis robertsii. 



Ceratobatis robertsii Boulenger, 1897, Ann. mag. nat. hist., ser. 6, 20, p. 227. 



"The band of teeth occupying only half the width of the mouth, its width 

 ten times in its length; teeth tessellated, hexagonal, two to three times broad as 

 as long, rugose with numerous obtuse ridges. Mouth inferior, wide. Pupil 

 vertically elliptic. Body smooth; pectoral fins with nearly straight, shghtly 

 convex anterior and slightly concave posterior border. Cephalic fins measuring 

 a little less than the width of the mouth ; spiracles behind the eyes. The space 

 between the last branchial clefts one fourth that between the first. Dorsal 

 fin between the ventrals. Tail slender, without spine, nearly twice as long as 

 the body. Length of disk without cephalic appendages 0.350, width of disk 

 0.780, cephalic fin 0.090, width of mouth 0.105, diameter of eye 0.012, ventral 

 fin 0.070, and tail 0.620 metres. 



Black above, white beneath. Grows to a very large size. 



Jamaica." 



Manta. 



Manta Bancroft, 1829, Zool. journ., 4, p. 454. 



Ceratoptera Muller & Henle, 1837, Sitzb. Akad. wiss. Berlin, p. 118. 



Head broad, flat, truncate; mouth very wide, anterior; internarial space 

 very wide; rostrum short, broad; rostral fins distinct from the pectorals, directed 

 forward. Teeth on the lower jaw only, very small, in numerous rows. Tail 

 slender, whip-hke, without (? or with) a serrated caudal spine (Lesueur states 

 that a spine is present on specimens of M. hirostris). A small dorsal between the 

 ventrals. It is not known whether the cephalic fins are rolled as in Mobula. 



Teeth extending over whole width of lower jaw 



rows separated, about 100 hirostris (page 454) 



Teeth not extending over whole width of lower jaw 



rows close together, about 200 .... ehrenbergii (page 455) 



Manta birostris. 



Manta birostris Walbaum, 1792, Artedi, p. 535; Donndorff, 1798, Zool. beytr., 3, p. 879. 

 La raie manatia LACEPi^DE, 1798, Poissons, 1, p. 160, pi. 7, f. 2. 

 Raia manatia Schneider, 1801, Bloch Ichth., p. 364. 

 Raia fimbriata Lac6p£;de, 1802, Poissons, 4, p. 677, pi. 16, f. 3. 



Cephalopterus vampyrus Mitchill, 1824, Ann. N. Y. lye, 1, p. 23, pi. 2, f. 1; 1832, Isis, p. 1063, pi. 28, 

 f. 4; DeKay, 1842, N. Y. fish, p. 377, pi. 67, f. 219- 



