VERTEBRATE PALAEONTOLOGY IN 1910 ^yj 



ment reptiles, exclusive of chelonians and most of the 

 anomodonts, are divided into four sub-classes : (i) Protorosauria; 

 (2) Enaliosauria ; (3) Lycognatha, and (4) Hyperosauria. The 

 first includes the orders Protorosauri, Naosauri ( = Pelyco- 

 sauria), Procolophonii, Sphenodonti =(Rhynchocephalia), and 

 Champsosauri ; the second embraces the Mesosauri, Ichthyo- 

 sauri, Sauropterygii, and Placodonti ; in the third are placed the 

 Lacerti, Ophidii, and Mosasauri; while the fourth is represented 

 by the Dinosauri, Loricati ( = Crocodilia, inclusive of Parasuchia), 

 and Pterosauri. 



Commencing a review of systematic work with the group 

 last mentioned, that is to say the one commonly known as 

 Ornithosauria, the first paper for notice is an elaborate descrip- 

 tion, by Mr. G. F. Easton, published in the Mem. Connecticut 

 Acad. Sci. and Aris, vol. ii. pp. 1-38, of the osteology of the giant 

 toothless American Cretaceous pterodactyles of the genus 

 Pteranodon. This memoir is illustrated by 31 plates, the last two 

 of which are devoted to restorations of the entire skeleton. The 

 second of these illustrates the extraordinary length of the skull, 

 which, inclusive of the supra-occipital prolongation, is about 

 one-third greater than that of the body and tail. This supra- 

 occipital spine is an ultra-development of that which occurs in 

 chameleons and the Chelydridce ; and, as in those groups, is 

 doubtless for the purpose of affording attachment for the power- 

 ful temporal muscles necessary to work the huge jaws. Equally 

 noticeable in the figure is the extraordinarily small size of the 

 pelvis, which, according to the author, appears to have been 

 connected by means of cartilage with the sternum. In P. ingens 

 the wings, even when slightly flexed, had a spread of no less 

 than 22 ft. 3 in., while, if stretched to their full extent, the 

 measurement would be about 5 per cent. more. Possibly even 

 these enormous dimensions were exceeded in another species. 



Very interesting is a paper given by Dr. R. S. Lull, published 

 in Amer. J. Set'., vol. xxix. pp. 1-39, on the distribution of 

 dinosaurs. At present dinosaurian remains are unknown from 

 Central and North-eastern Asia, but this may be attributable 

 either to lack of knowledge of the palaeontology of that area or 

 to the circumstance that these reptiles never occurred there. 

 The theropod group is believed by the author to have originated 

 in North America, whence it migrated in one direction, probably 

 at a late epoch, into South America and in another by way of 



