EXPLANATIO\ OF PLATES 20. 21. 22. 31 



Plate 20. V. I. p. 167. 



Head of the Mosasaurus, or Great Animal of Maestricht. 

 (Cuvier.) 



Plate 21. V. I. p. 171. 



Pterodactylus longirostris in the lithographic slate of 

 Aiehstedt. (Cuvier and Goldfuss.) 



In this Plate, and Plate 22, the same letters and figures 

 designate the corresponding Bones in the different Animals 

 to which they are affixed ; they are copied chiefly from the 

 figure and Explanations of Dr. Goldfuss, in his Beitrage zur 

 Kenntniss verschiedener Reptilien der Vorwelt. 



r. Cavitas narium. 



A. Cavitas intermedia. 



e. Orbita. 



a. Maxilla superior. 



b. Vel os nasi vel inter-maxillare? 



c. Operculum nasale. 



d. Aut os frontis anterius vel nasale ? 



e. Os frontis proprium. 



f. Os parietale. 

 g. Os petrosum. 



H. Pars basilaris ossis occipitis. 

 h. Pars lateralis, 

 i. Os tympanicum s. quadratum. 

 k. Os frontis posterius. 

 1. Os mastoideum. 

 m. Os zygomaticum. 

 n. Aut os lacrymale vel superciliare ? 

 o. Annulus orbitalis. 

 P. Corpus ossis sphenoidei. 

 p. Processus transversus ossis sphenoidei. 



