332 DR. ST. GEOEGE MIT ART OX THE SKELETON OP [Apr. 2, 



The Jirst caudal vertebra has a small, quadrate, low, neural spine 

 (n) and two prezygapophyses which extend but very slightly 

 forwards, while the postzygapophyses are very small indeed. The 

 transverse processes are simple, flattened above and below, and 

 about as long as those of the last uro-sacral vertebra. The ventral 

 surface of the centrum presents at its ventral margin two blunt 

 hypapophysial processes, which abut against the postero-inferior 

 margin of the sacrum. 



The second caudal vertebra is similar to the last except that the 

 neural spine is not so quadrate (being highest preaxially), the 

 prezygapophyses (pr) are slightly larger, the postzygapophyses 

 more developed, while small hyperapophyses reappear upon them. 

 The transverse processes (i) are slightly longer, while the two 

 hypapophysial processes are clearly approximated and project 

 slightly more preaxiad. 



The third caudal vertebra has again the same characters carried 

 slightly further, while the hypapophysis has become single and 

 projects slightly forward beneath, and applied to, the ventral 

 sui-face of the second caudal. 



The fourth caudal vertebra has its neural spine and prezyga- 

 pophyses inclined strongly preaxiad, the hyperapophyses slightly 

 larger and the transverse processes shghtly longer (both are here 

 at their maximum in the caudal region), while the hypapophysis is 

 a little more developed, ventrally grooved antero-posteriorly, and 

 tending to bifurcate at the apex, and developed, as before, from the 

 preaxial end of the centrum. 



The fiph caudal vertebra has its transverse processes slightly 

 shorter, the neural spine less inclined preaxiad, and hyperapophyses 

 much smaller and more preaxially placed. The hypapophysis is 

 long, situated at the preaxial margin of the centrum, and bifurcates 

 distally. 



The sixth caudal vertebra has all its parts and processes dimin- 

 ished save the hypapophysis Qi), which is somewhat longer and 

 stouter, stiU less inclined preaxiad, but stUl distally bifurcating 

 into two lateral processes diverging sUghtly more than those of 

 the fifth caudal vertebra. 



The Ptgosttlb. 



The pygostyle in L.JIavopaTliatus (^3?/, fig. 12, p. 324) is a laterally 

 much compressed subquadrate plate of bone with anterior, superior, 

 and posterior margins, while inferiorly it carries on, as it were, the 

 series of caudal vertebrae. At its preaxial end below are minute 

 transverse processes and prezygapophyses, which latter adjoin the 

 corresponding parts of the last caudal vertebra. 



From its ventral surface a process depends which is in series 

 ■with the hypapophyses in front. 



The preaxial margia of the plate is strongly concave, the post- 

 axial margin slightly so. The former margin is entirely thin, but 

 the posterior one is medianlv thin but thickened, though flattened, 



