500 Memoir Sears Foundation for Marine Research 



a valve (Fig. i 15B). Mouth occupying about Vs of width of head; edge of lower jaw 

 bowed slightly forwards. Tooth band of upper jaw narrowly fusiform, occupying a little 

 less than half (45 */o) of breadth of mouth; its length (anteroposteriorly) about 14-15 °U 

 as great as its transverse breadth. 



Upper teeth in 36 series; each tooth with a sharp posterior edge, sometimes scal- 

 loped in two to four blunt lobes, and with a tuberculated anterior edge. No teeth in 

 lower jaw, and no trace of teeth below the skin. 



Cephalic fins about 1.4 times as long as broad (their length measured from mouth); 

 their dorsoventral axes sloping slightly outwards from above to below, their bases termin- 

 ating about under spiracles at level of lower surface of head; their anterior margins 

 turned towards axial plane of body (in preserved state). Main portions of pectorals 

 originating close behind spiracles immediately above level of latter; their anterior mar- 

 gins weakly convex, increasingly so toward outer corners; their posterior margins 

 slightly concave; inner margins overlapping pelvic fins, moderately convex toward 

 axils; outer corners narrowly pointed, as illustrated (Fig. 115); rear corners angular, a 

 little less than a right angle (75-80°). Dorsal fin of shape illustrated (Fig. 115); its 

 free rear corner about even with midpoints of inner margins of pelvics. Pelvics extending 

 only a little beyond posterior corners of pectorals; outer margins nearly straight, pos- 

 terior outline wedge-shaped (Fig. 115D). 



Color. Upper surfaces of disc, pelvics and dorsal fin, and upper surface and sides 

 of tail, blackish brown after preservation for many years, the dark shade extending down 

 sides of head to surround eyes, more diffuse behind eyes than around their rims. Upper 

 margins and in-turned distal portions of cephalic fins also dark, their out-turned surfaces 

 whitish; lower surfaces of disc, pelvics and proximal portion of tail whitish. 



Size. The single known specimen (type) is only 770 mm wide. 



Habits. Nothing whatever is known of its way of life. 



Range. The only known specimen was from Jamaica. 



References : 



Ceratobatis robertsii^'^ Boulenger, Ann. Mag. nat. Hist., (6) 20, 1897 : 227 (descr., meas., size, color, Jamaica); 

 Jordan and Evermann, Bull. U. S. nat. Mus., 47 (j), 1898: 2756 (descr., meas., size, color, Jamaica, 

 from Boulenger, 1897); Gill, Science, N. S. 18, 1903: 473 (discuss., by ref to Boulenger 1897); Smith- 

 son, misc. Coll., ^2 (2), 1898: 176 (length of tail); Garman, Mem. Harv. Mus. comp. ZooL, j6, 191 3 : 

 454 (descr., from Boulenger, 1897); Jordan, Evermann, and Clark, Rep. U. S. Comm. Fish. (1928), 

 2, 1930: 32 (listed, Jamaica); Whitley, Aust. Zool., 8 (3), 1936: 188 (listed, by ref to Boulenger, 

 1897). 



Possible Synonym: 



Squalus edentulus Briinnich, Ichthyol. Massil., 1768: 6 (dried head with cephalic fins, but no teeth in lower 

 jaw; local, not stated). 



Genus Manta Bancroft 1828 

 Manta Bancroft, Zool. J., 4, 1828: 454; type species, M. amerkana Bancroft. Jamaica. 

 125. Sometimes spelled robertsi. 



