THE lOHTHYOSAUKIA. 



209 



The spinal column is only distinguished into two regions, 

 caudal and precaudal, inasmuch as the ribs, beginning at the 

 anterior part of the neck, are continued, without being con- 

 nected with the sternum, to the posterior end of the bodj- ; 

 and there is no sacrum. The caudal region, however, is dia 



Fig. 76. — Different parts of the skeleton of lehthyosaurit^i intermediuHy drawn to the sama 

 scale. A, the skull; B, the fore-limb: JT^ humerus; Ji^ radius; JT^ ulna; ?'. i. u., radi- 

 ale, intermedium, ulnare; Cp^ carpalia; 1, 2, 3, 4, 5, digits : m.n «i.«. radial and ulnar 

 marfiinal ossicles. — C, a dorsal vei-tebra, with the ribs {R) and ventral ossiiicntiong 

 iV.O). — D. the hind-limb: F^ femur; T, tibia; Fb^ fibula; t^ «,/, tibiale. intermedium, 

 flbubire ; T». tarsalia ; Mt, metatnrsalia ; P\ phalanges ; m, i&, tibial marginal ossicloa 

 — E, the pectoral arch, seen Iron- the ventral siiit ; F, the same aspect of the pehic arch. 



