HIMANTURUS. 375 



Dasybatus. 



Dasybatus Klein, 1742, Hist. pise, miss., 3, p. 34; 1775, Neuer schaupl., 1, p. 991; Walbaum, 1792, Art. 



gen. pise, p. 581. 

 Trygonobatus Blainv., 1816, Bull. .Soc. philom. 

 Trillion Cdv., 1817, Reg. anim., 2, p. 136; Muller & Henle, 1837. 

 Himantura Muller & Henle, 1837. 

 Hypolophus Mullek & Henle, 1837. 



Disk subquadrangular to subcircular, smooth or with spines and tubercles. 

 No rayed dorsal fins. Pectorals meeting in front of the skull. No rostral carti- 

 lage supporting the snout. Anterior copula of branchihyal cartilages segmented. 

 Tail elongate, whip-like, with a serrated caudal spine, with or without dermal 

 fin-folds or keels behind the spine, and without lateral folds on the base. Pelvis 

 without a prepelvic process. 



For convenience the species of this genus may be arranged by means of the 

 cutaneous folds on the tail in four more or less distinct groups. 



Tail without keels or folds 



Type D. uarnak Himanturus (page 375) 



Tail without a keel above, with a fold below 



Type D. sephen Pastinachus (page 381) 



Tail with a keel above and a fold below 



Type D. pastinacus Dasybatus (page 388) 



Tail with folds both above and below 



Type D. sabinus Ampholislius (page 392) 



Himanturus. 



Cutaneous folds or keels on the tail none 



disk broader than long; tubercles depressed, in pavement 

 tail thrice the length of body, or more; papillae 4-7; 



brown with dark spots, tail banded . . uarnak (page 376) 

 tail twice length of body, or more; papillae 2 



brown with yellow reticulations . . . favus (page 377) 

 tail three times length of body, or more; papillae 4 



brown with lighter spots, tail banded . gcrrardi (page 377) 



tail twice length of body, or more; papillae 4 



brown with paler spots; snout pointed . . alcocki (page 378) 

 tail once length of body, or more; tubercles rounded 



olive, tail grey; snout pointed; papillae 4 jenkinsii (page 378) 



