THE ICHTHYOSAURIA. 



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 body ; 

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



Fig. 76. — Different parts of the skeleton of IchtJiyosanrvs inter'medivs, drawn to the sam'j 

 scale. A, the skull; B, the fore-limb: H^ humerus; E^ radius; U^ ulna; r. i. u., radi- 

 ale, intermedium, ulnare; Cp, carpalia; 1,2, 3, 4, 5, di^ts ; m.i'. m.u. radial and ulnar 

 marginal ossicles. — C, a doi-sal vertebra, -with the ribs (i?) and ventral ossifications 

 {V.O).—Y>. the hind-limb: F, femiir; T, tibia; Fh, fibula; t, i,f, tibiale. Intermedium, 

 fibulare; Ts, tarsalia; Mt, metatarsalia ; P/i, phalanges; m, tb, tibial marginal ossicles 

 — E, the pectoral arch, seen from the ventral side ; F, the same aspect of the pelvic axch 



