386 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



The discrepancies with few exceptions have been slight and incon- 

 clusive, while the agreements have been fundamental. We have 

 found our data in agreement with: a, the early existence of Equa- 

 toria ; h, an early division of South America into three land masses, 

 Guiana-Brazil on the east, Ecuador on the northwest and Argentina- 

 Patagonia on the south ; c, a later separation of eastern Brazil from 

 the (iuianas and a subsequent union of the Guianas to Ecuador; fZ, a 

 still later union of all these land masses to form the present South 

 American continent ; e, late formation of the Isthmus of Panama ; /, 

 connection at a subsequent period between Central America and the 

 West Indies and also between North America and Asia by waj' of 

 Alaska; g, Antarctic connection between Patagonia and Australasia 

 at a time when" Patagonia-Argentina was separated from northern 

 South America; and of the disappearance of the Antarctic connec- 

 tion before northern and southern South America united; A, an 

 early presence of an equatorial and a southern trans- Atlantic land 

 bridge, of which the southern was the first to disappear; and i, con- 

 nection between Ecuador and Siberia by the Ecuador-Tehuantepec- 

 California-Alaska-Siberia land strip. We have found no evidence of 

 direct trans-Atlantic connection between North America and 

 Europe. The connections of Papua at different periods need further 

 study, and the distribution of the Ranid genera Polyy eclat es and Rana 

 seems to argue against the conception that Madagascar retained its 

 connection with Africa after it separated from the trans-Indian 

 Ocean ridge. The presence in Wyoming of ^a Comanchian or 

 Eocene Oxyglossus can not apparently be brought into agreement 

 with our charts. 



The tabic on pages 272-285 shows one point of some interest, which 

 it may be well to summarize, namely, the number of hosts and 

 the degrees of relationship between the hosts from which each 

 of the several species and subspecies of Opalinids have been re- 

 ported. There are listed below the species of Opalinidae which are 

 known from more than one host. Protoopalina axonxwleata from 

 Bufo Jjufo asiaticiis^ and its form lata from Rana nigrmnaculata; 

 Protoofalina caudata from Bomhina homhina, B. pachypa, Bufo 

 calamita,B. mauntanicus, and Bufo viridis; Protooj^alinu ijitestinalls 

 from Bomhina homhina, B. pachypa, Discoglossus pictus ( ? ) Pelo- 

 hates cult ri pes ( ? ) , Rana esculenta, Uperoleia marmorata ( ? ) , Hyla 

 aurea (?), ^. ewingii (?), and Triturus vulgaris [Triton taeniatus\; 

 Protoopalina tenuis from Crinia signifera and Uperoleia marmorata; 

 Zelleriella antillensis is reported from eight species of hosts belong- 

 ing to two families, but the specific identity of these Zelleriellas is 

 improbable; Zelleriella dendrohatidis from Dendrohates tinctorius 

 jiTid D f>/pographus; Zellenella engystomopsis from Engystomops 



