No. 605] 



ATURE 



(including Cricotus, Eryops, Dissorophus and many others) are 

 all genera not found in the Lower Coal Measures, and it abounds 

 in reptiles of several orders and many families. Some of this 

 difference may be due to the fact that the Lower Coal IMeasures 

 fauna represents only the life of the coal swamps, while the 

 Texas fauna represents the life of the pools and streams of a 

 wide delta country (Case) ; but all authorities agree that the 

 former is much the older of the two. 



The Lower Coal Measures fauna is far more similar to the Per- 

 mian fauna of Bohemia, which according to Fritsch's classifica- 

 tion comprises a similar series of 13 families, 26 genera and 63 

 species, of branchiosaurs, microsaurs and temnospondyls. But 

 no genera are common to the two countries and many of the 

 "families" (as listed) are peculiar to one or the other. The 

 families peculiar to America are the Cocyctinid^, Peleontidae, 

 Tutidanidffi, Ptyoniidae, Molgophiidse, Sauropleuridae, Amphiba- 

 midffi, Ichthyeanthidae, Stegopidse, Macrepetidae, while those 

 peculiar to Europe are the Apateonidse, Limnerpetidffi, Micro- 

 bra chid^e, Dolichos&ma, Ophiderpeton, Melosauridae and Arche- 

 gosauridae. The families common to both continents are: 

 BranchiosauridsB, Diplocaulidffi," Hylonomidse, Urocordylidse, 

 Nyraniida?,^ Cricotidse (Diplovertebridje), Anthracosauridae, 

 Mastodonsauridae. 



Professor Case has directed attention* to tlie marked resom- 

 blance of two of the genera {Diplon rtfhmn. Marromrrion) 

 from the lowest Bohemian horizon (Nyran) to Cric(jfu!i of the 

 Upper Coal Measures of North America, as furnishing ewdeiice 

 that the Bohemian deposits are of Upper Carboniferous age. 



Subsequent research may well show on the one hand that some 

 of the American "families" are more closely related to European 

 groups than is now recognized and on the other hand that some 

 of the "families" classed as common to both continents are 

 artificial or ill defined (Hylonomida??, Nyraniidae?) ; yet even 

 with our present imperfect knowledge it appears that the Lower 

 Coal Measures fauna of America and the "Permian •• fauna of 

 Europe represent nearly identical life conditions and similar 



