182 LABYRINTHODONTIA. 



29005. Part of a split nodule exhibiting that portion of the ventral 

 armour of an immature individual where the reversing of 

 the direction of the lines of the scutes takes place. 



Purchased, 1859. 



R. 1750. A split nodule showing the imperfect median thoracic 

 plate. Purchased. 



R. 534. A plaster model in relief taken from a nodule showing the 

 impression of part of the vertebral column and ribs. The 

 portion showing the pleurocentra, intercentra (hypocentra), 

 and ribs is figured by Fritsch in his ' Fauna der Gas- 

 kohle,' vol. ii. p. 14, fig. 123. 



Presented by Dr. Anton Fritsch, 1885. 



R, 1471. A plaster model in relief taken from a nodule showing 

 the impression of the lateral aspect of three vertebrae. 

 Original figured by Fritsch, pp. cit. pi. lviii. fig. 13. 



Purchased. 



R. 1455. A plaster model in relief taken from a nodule showing the 

 impression of the ventral aspect of four caudal vertebras. 

 Fritsch regards this specimen as being of an embolo- 

 merous type, the ribs being attached to the intercentra. 

 The original is figured in pi. lviii. fig. 14 of the work 

 cited. Purchased. 



Genus PLATYOPOSAURUS, Lydekker \ 

 Syn. Platyops, Twelvetrees 2 . 



Apparently closely allied in cranial characters to Archegosaurus, 

 but the infoldings of the teeth sinuous instead of straight, and the 

 orbits more rounded. 



The relatively greater length of the facial portion of the skull as 

 compared with Archegosaurus would not, judging from the analogy 

 of the Crocodilia, of itself be a generic distinction. 



This genus has been placed by Zittel 3 with the Anthracosauridce, 

 but Trautschold 4 figures a horseshoe-shaped intercentrum like that 

 of Archegosaurus. 



1 In Nicholson and Lydekker's ' Manual of Palaeontology,' 3rd ed. vol. ii. 

 p. xi (1889). 



2 Bull. Soc. Moscou, vol. lv.pt. i. p. 117 (1880).— Preoccupied by Platops, 

 Newp. 1844. 



3 Handbuch der Palscontologie, 1 Abth. hi. Band, 2 Lief. p. 399. 



4 Mem. Soc. Moscou, vol. xv. pt. i. pi, iii. 



