354 MEMOIRS OF THE CARNEGIE MUSEUM. 



present. Except in two families the branchial arches and clefts are invariably five 

 in number. An operculum is not developed." (T. W. Bridge, Cambridge Natural 

 History, Fishes, p. 442). 



Suborder BATOIDEI. 



" Body generally discoidal or rhombic in shape, the axial portion being formed 

 by the flattened head and trunk, and the lateral portions by the enormously ex- 

 panded pectoral fins, which are usually confluent with the sides of the head. Tail 

 slender, sharply marked off from the trunk, to which it usually appears as a mere 

 appendage. Dorsal fins, when present, on the tail. Anal fin absent. Branchial 

 clefts ventral in position. Spiracles large, usually crescentic. Vertebrae tecto- 

 spondyhc." (T. W. Bridge, I. c, pp. 457-8). 



Family RHINOBATID^. 



"Tail strong and long, with two well-developed dorsal fins; a caudal and a 

 longitudinal fold on each side. Disk not excessively dilated, the rayed portion 

 of the pectoral fins not being continued to the snout. No electric organs in the 

 Hving forms." (A. S. Woodward, Cat. Fishes B. M., Pt. I, p. 77). Teeth smaU, 

 numerous, in pavement. 



Genus Belemnobatis ThioUiere. 

 " Tail very distinct from the disk, which is almost of rhombic shape. Pectoral 

 fins not extending forwards beyond the base of the snout; pelvics not notched. 

 Tail with two smooth spines upon the proximal half, and apparent/?/ two dorsal 

 fins on the distal half, without caudal fin. Body partially covered with conical 

 dermal tubercles, the larger only superficially calcified. Teeth minute, smooth." 

 (A. S. Woodward, I. c, p. 83). 



1. Belemnobatis sismondae ThioUiere. 

 1854. Belemnobatis sismondce ThioUiere. 



Poiss. Foss. Bugey, Pt. I, p. 8; pi. Ill, fig. 1. 

 1873. Belemnobatis sismondce ThioUiere. 



Op. cit., Pt. II (ed. P. Gervais), p. 12; pi. I, fig. 1. 

 1889. Belemnobatis sismondce A. S. Woodward. 



Cat. Foss. Fishes Brit. Mus., Pt. I, p. 84. 



Type. — Complete skeleton; present location unknown. 



" Snout moderately obtuse; tail shorter than disk. Dermal tubercles largest 

 between the pelvic fins; of considerable size along the median line of the back and 

 on the anterior portion of the disk." (A. S. Woodward, I. c, p. 84). Total length 

 upwards of 50 cm. 



