314 



MR. R. H. BURNE ON THE 



[Apr. 18, 



in transverse diameter x 26 mm. in depth. Its hinder parts are 

 encased in a thick cartilaginous sclerotic, which thins out anteriorly 

 where it meets the circlet of sclerotic bones. 



The latter i-esemble those of Chelone in form, number, size, and 

 ari'rangement, but are stouter. 



Text-fiff. 68. 



..pyn> 



n,m/ 



Dermccheli/s coriacea, lids of the left eye seen from within. 



LI. lower lid, I. p.m. levator palpebrsu muscle, n. nictitating membrane, 

 n.m. nictitator muscle. 



The outer parts of the sclerotic cartilage are hyaline, but 

 towards the innei- surface it gets more and more fibrous, the inner 

 parts consisting of fibrous tissue interspereed with small and 

 scattered centres of cai'tilage formation. 



The lens, like that of Chelone, is relatively very small ; it 

 measures 7 mm. in the antero-posterior and 7*5 mm. in its trans- 

 verse diameter. 



The Alimentary System. 



The genei-al anatomy of the alimentary canal has been accurately 

 described by Rathke*, and more recently by Yaillantf. The 

 following additions may be made to their accounts of these organs. 



The (Eso2:)hagus. 

 (R. C. S. Museum, Physiol. Series 461 B, 0, & D.) 



The horn-capped piocesses that beset the inner surface of the 

 oesophagus are of all sizes. The larger ones average about 4 cm. 

 in length, and, except in the pharyngeal region, ai-e set so close 



Rathke : " Ueber die Luftrohre, die Speiserohre und den Magen der Spliargis 

 coriacea," Arch. f. Anat. u. Physiol. 1846, p. 292. 



t Vaillant : " Remarques sur I'appareil digestif et le mode d'alimentation de la 

 lortue luth," Comptes Rendus Ac. Sci. t. cxxiii. 1896, p. 654. 



