30 THE EXTINCT BATRACHIA, REPTILIA 



EOSAURUS, Marsh* 



This genus, as suggested by Huxley, may be the type of a peculiar division of the 

 Batrachia. There appears to be some probability of this being found to be the case, though 

 present evidence is in favor of Prof. Marsh's location here. 



EOSATJRTJS ACADIANTJS, Marsh. 

 Amer. Jour. Science, xxxiv. 1S62, 1 Tab. I, II. 



Coal measures : Joggins of Nova Scotia. 



ARCHOSAI7RIA. 



This great order of Reptilia corresponds with the Monimostylica of Midler, without 

 the Testudinata. The latter differ too much in the vertebral and sternal structure to be 

 retained in it. 



The important feature which characterizes the order, the close sutural attachment of 

 the quadrate bone, may be readily understood by comparison of the accompanying figures 

 of Nothosaurus from the Muschelkalk of Germany, and Mecistops intermedins Graves,f 

 recent, from the Orinoco, with the plate of Clidastes propython, at the end of the volume. 



The order embraces that large series of forms which seem to be equidistant between 

 all the extremes of the Reptilian type. It therefore is not a strictly homogenous group ; 

 yet its subdivisions do not appear, with present knowledge, to be sufficiently marked, to 

 render it proper to esteem them of equal value with the other orders here enumerated. 

 This is a usual difficulty of classification ; Ave express it, and do not remove it, by admitting 

 the existence of a protean type in a genus of species, a family of genera, a class of orders, 

 etc., etc. The suborders are as follows : 



Limbs without flexible articulation ; natatory ; no femoral trochanters ; no sacrum. 

 A procoracoid united with scapula ; a distinct episternum. 

 Ribs single headed. 



# The following species have been described by Leidy, who refers them to Reptilia with doubt, and says they may- 

 be fishes. As this point remains undecided, I can only allude to them here. 



CYMBOSPONDYLUS, Leidy. 

 Proceedings Acad. Nat. Sciences, Philada., 1858. — 178. 



CYMBOSPONDYLUS PISCOSUS, Leidy, I. c. 

 ? Triassic of Humbuldt Co., and of the Toiyabe Range, Nevada. 



CYMBOSPONDYLUS PETRINUS, Leidy, I. c. 

 ? Triassic ; Humboldt, Nevada. 



f This cut is taken from the type specimen of Mecistops bathryliyncTius, in Mus. Academy. The Nothosaurus is 

 the N. andriani or a nearly allied species. I am not quite positive that the number of alveoli on the maxillary bone 

 is exactly correct. 



