AECHEGOSAURIDJS. 189 



of the same volume. If the latter restoration be correct, 

 the iutercentrum (hypocentrum arcale of Fritsch) will be 

 greatly developed, and the central elements (pleurocentra 

 and hypocentra pleuralia of Fritsch) proportionately re- 

 duced. Purchased, 1888. 



Genus SPARAGMITES, Fritsch 1 . 



Syn. Calochelys, Fritsch 2 . 



Known only by a portion of the vertebral column of a small 

 form, in which the neural spines are low and semicircular; the 

 general structure being similar to that of Chelyosanrus. 



Sparagmites lacertinus, Fritsch 3 . 



Syn. Calochelys lacertina, Fritsch 4 . 



The type and only described species. 

 Hah. Europe (Bohemia). 



R. 1450. Electrotype from a fragment of shale, showing part of the 

 vertebral column. The original is the type, and was 

 obtained from the Gaskohle (Lowest Permian) of Nyf an 

 (Pilsen) ; it is figured by Fritsch in his ' Fauna der Gas- 

 kohle,' vol. ii. pi. lii. fig. 1. Purchased, 1888. 



Genus TRIMERORHACHIS, Cope 5 . 



Skull of moderate width and length, with the round orbits in the 

 anterior half, and the nares very widely separated from one another 

 and approximated to the orbits : occipital condyles unossified ; two 

 rows of upper and one row of lower teeth ; cranial sculpture net- 

 like. Vertebrae (fig. 46) without distinct neural spines, and the 

 ossification of the intercentral and pleurocentral elements very 

 superficial. 



The absence of neural spines to the vertebrae distinguishes the 

 present genus from all the others of the group, and the genus is 

 accordingly regarded by its founder as the type of a family — T ri- 

 mer orhachidce. 



1 Fauna der Gaskohle, vol. ii. pt. i. p. 15 (1885). 



2 Ibid. vol. i. pt. i. p. 28 (1879). — Preoccupied by the Chelonian Callichclys, 

 Gray (1863). 



3 Loc. cit. — Calochelys. 4 Loc. cit. 

 5 Proc. Amer. Phil. Soc. vol. xvii. p. 524 (1878). 



