

i}^.,. 



n 



m^ 





['■■W' 



■H*i\".' 





tc 



those emptying i' tlie Gulf of Mexico toward the east and northeast, 

 until we reach vers of IMassachusetta and Maine, where the great- 



est modilication oi the fauna exists. The latter fact has been pointed 

 out by Agassiz, who calls this region a "zoological island," and enn 

 merates the characteristic Nearctic genera which are wanting there. 1 

 give now a list showing the points at which ^Mississippi genera cease, as 

 we follow the rivers of the Gulf and Atlantic coasts, so far as our 

 present knowledge extends. 

 Gulf rivers: Ilaploidouotits has not yet been indicated from eastward 



of these, except in the Lake area. 

 Tioanoke : CAimpoHtoma ceases here. 

 James : 2[icroptcruf< and AmhlopUtvH cease. 

 Potomac : Fomo.njs, according to Professor P>aird (verb, comnin.), ceases 



here. 

 Susquehanna: Ccratichthys, I^joylossum, Chyofiomus, Crtrj>/of7t'.s', cease. 

 Delaware : CUnostomus, Hi/pnilcpis analontanus, UnncacaniJius, and Lcpi- 



dostciifi cease. 

 Hudson : <Semofi?j<.s' corjw>Y<7<,s', according toF.W. Putnam (verb, commn.), 



ceases. 

 The types remaining in the Atlantic waters of the New England dis- 

 trict (IV) are first, then, SaJmo, Esox, xingHllla, Perca ; and, secondly, tlio 

 general types Boleosoma. Semotilus, Ilijpiiilcjns, Stilbe, ITyhopsis [bi/rc- 

 natufi), Fitnfhtlm, and A7niurufi ; and the Lake types Lota and Coref/onns'. 



VII. — THE CJLN'TKAL REGION. 



VIP. Species peculiar to the Central region — 12 : 



Amira. 

 Spea bombifrous. 



Ophiilia. 



Ophibolus multiatratus. 

 Eutaenia radix. 

 Eutaenia vagraus vagrans. 

 Eutaenia sirtalis parietalis. 



LacertUia, 

 Eumeces septentrionalis. 

 Eumeces inornatus. 

 Eumeces multivirgatus. 

 Holbrookia maculata maculata. 

 Phrynosoma douglassii douglassii. 



