460 FISHES CHAP. 
extinct genus Sclerorhynchus from the Upper Chalk of Mount 
Lebanon, in which the smaller size and more superficial position 
of the rostral “teeth,” and the absence of sockets in the rostral 
cartilage, prove that the “teeth” approximate more to ordinary 
dermal spines in this genus than in any of the more recent Saw- 
Fishes. An extinct genus Propristis, from the Upper Eocene of 
Egypt, with non-socketed teeth, and species of the existing genus 
Pristis from the English Middle Kocene, are also known. 
Fam. 2. Rhinobatidae——Owing to the increased expansion 
of the pectoral fins and the forward growth of their anterior 
cutaneous portions along the sides of the head, as well as back- 
wards along the trunk, the body now assumes a sub-rhombic 
shape, and approximates to the disc of the more typical Batoidei, 
Fic. 263.—Rhinobatus granulatus. (From Miiller and Henle.) 
but the tail with its dorsal and caudal fins is still strongly 
developed, and blends imperceptibly with the trunk in front. 
Teeth very obtuse. No electric organs. About five genera and 
twenty species are known, distributed in most tropical and sub- 
tropical seas. 
The cosmopolitan Rhinobatus is represented by species from 
the Mediterranean, the Red Sea, the west coast of Africa, the 
Indian Ocean, Australia and China, as well as from the Atlantic 
and Pacific coasts of America, and the Galapagos. Rhynchobatus 
ranges from the Red Sea through the Indian Ocean to China, 
Zapteryx occurs at San Diego and Panama, and Platyrhinoidis 
on the Californian coast. Zrygonorhina is an Australian 
genus. 
The family dates from the Upper Jurassic. Rhinobatus is. 
