55 ROY L. MOODIE. 



wise arise from broad bases. The disparity in size between the 

 two pairs of processes of the sacrals is such that the anterior pair 

 appears to bear all of the burden of support (Fig. i). In the 

 specimen of Sceloporns the transverse processes are of more nearly 

 equal size but are longer than in the Chameleon. In Draco the 

 processes are stout and end broadly. In Iguana the transverse 

 processes of the sacrals are of equal strength and have broad 

 ends. In Heloderma there are broad transverse processes sup- 

 porting the pelvis. In Cnemidophorns the sacral vertebrae bear 

 stout transverse processes of which the anterior pair is the larger. 



One would expect to find a suture of separation between the 

 processes and the sacral centra of young lizards did such a sepa- 

 ration really exist but even in the youngest of my specimens, 

 Sceloporus, which are two days old and in which the epiphyses 

 are just beginning to appear as minute centers of ossification, 

 there is not the slightest indication of any separation between the 

 sacral centra and their transverse processes. But we have more 

 positive evidence still, that there are no sacral ribs in the lizards. 

 In an embryo of Cnemidophorus sexlineatus Linne which measures 

 24 mm. from the tip of the snout to the base of the tail and in 

 which the diaphyses of the limb bones are only one half ossified 

 and the epiphyses have not appeared at all, the broad connection 

 of the transverse processes to the centra of the vertebras is 

 clearly apparent. Furthermore the ossification of the processes 

 is seen to be proceeding outward from the body of the vertebra 

 into the transverse process so that there is no chance for a sepa- 

 rate center of ossification in the processes. It can thus be very 

 definitely stated that the Lacertilia occupy an isolated place 

 among all other known reptiles in not having any sacral ribs 

 whatever. 



In nearly all of our modern text-books on zoology the state- 

 ment is made that there are sacral ribs in the lizards and in none 

 is a statement made to the contrary. Even Huxley (9) in his 

 work on the anatomy of vertebrated animals states that there are 

 sacral ribs but does not discuss the matter. Parker and Haswell 

 (10) in their "Text-Book of Zoology" make the statement: 

 "The sacral vertebrae have short and strong expanded proc- 

 esses — the transverse processes — which abut against the ilia, 



