ORDER ELASMOBRANCHEI. 



93* 



ton of the pectoral fin is shown in fig. 846 (p. 920). The body is 

 depressed, with the mouth placed anteriorly ; while the pectoral 

 fins are much produced anteriorly, although unconnected with 

 the head. The teeth are conical 

 and pointed ; and the dorsal fins are 

 without spine, and placed on the tail. 

 The only known genus is Squatina 

 (P/iina), which ranges from the 

 Kimeridgian upwards to the present 

 day; although some of the fossil 

 species have been described under 

 other names, such as Thaumas. 

 Beautifully preserved skeletons occur 

 in the Lower Kimeridgian litho- 

 graphic limestones of Bavaria, one 

 of which is shown in the accompany- 

 ing woodcut. Other species have 

 been named from the Chalk of the 

 Lebanon and of England, and also 

 from the Miocene and Pliocene of 

 the Continent ; while detached teeth 

 are found in the English Gault, the 

 London Clay, and the Red Crag. 



Family Pristid^:. — In the true 

 Saw-fishes the body is scarcely de- 

 pressed, the pectoral fins are not 

 much expanded, and the gill-slits are 

 placed inferiorly. The most charac- 

 teristic feature is, however, the so- 

 called " saw," which is a long and 

 flat calcified prolongation of the 

 snout, armed with a series of large 

 pointed teeth on either border. Re- 

 mains of the single existing genus 

 Pristis occur in the Middle Eocene 



of Barton and Bracklesham ; in the Middle and Lower Eocene and 

 Micoene of the Continent ; and the Eocene and Upper Cretaceous 

 of North America. Propristis, from the Eocene of Egypt, is said 

 to differ by the absence of calcification in that part of the "saw" 

 which supports the teeth ; Amblypristis, of the same beds, has 

 shorter and broader teeth than Pristis ; while Sclerorhynchus, which 

 may belong to the P?'istiopkoridcs, differs in the structure of the 

 " saw," and the small size of the rostral teeth. The latter family, 

 which has lateral gill-slits, may be represented in the Miocene of 

 Wiirtemberg by a species of the existing Pristiophorus. 



Fig. 853. — Ventral aspect of the skeleton 

 of Squatina speciosa ; from the Kimerid- 

 gian of Bavaria, two-thirds natural size. 

 «, Mandible ; b, Pectoral girdle ; c, Pec- 

 toral fin ; d, Pelvis ; e, Pelvic fin. 



