OPALINID CILIATE INFUSORIANS — METCALF 601 



Connection between South America and Africa, of which there is 

 general faunal evidence, may have been in the equatorial or sub- 

 Antarctic zone, rather than by way of Antarctica itself. 



Other opalmids reported from leptodactyhds are Protoopalinas, 

 their original guests, and Cepedeas, both infections occurrmg in South 

 America. The latter infection, by Cepedea rubra in three individuals 

 of Paludicolafalcipes, from Minas Geraes, Brazil, being the only report 

 of Cepedea from a reputed leptodactyhd, seems to cast doubt upon the 

 status of Paludicola as a leptodactyhd and to suggest its relegation to 

 the Bufonidae where it was long classed, but 1 know no competent 

 herpetoiogist who receives this suggestion kindly. (There was no 

 error in identification of these specimens ; they are now in the United 

 States National Museum.) The leptodactyhds never met Opalina 

 until after the middle Pliocene in Central America, and they have not 

 yet adopted it. Cepedea entered South America probably with Bufo 

 (see discussion of Bufo later), but leptodactyhds, though in contact 

 with it, have not welcomed it. They are resistant to infection by any 

 of the multinucleate opalinids. 



THE GASTROPHRYNIDAE (Fig. 154) 



The distribution of the Gastrophrynidae is puzzling. They are not 

 a numerous family and seem to be rather feeble amphibians. They 

 may at one time have had a wide distribution. Their presence in 

 Africa and Madagascar indicates origin before the separation of these 

 two lands, i. e., before the middle Cretaceous.^ Then: presence in 

 Ceylon and India agrees with this date of origin. Their absence from 

 Austraha is evidence (not conclusive, of course) that they were not in 

 Asia-Malaysia much earlier than this, for Austraha probably had 

 Malaysian land connection earlier than the Cretaceous (in the Juras- 

 sic). But it is unsafe to rely upon negative evidence from such an 

 apparently more or less decadent family. AustraUan climatic condi- 

 tions have suffered great changes since the early Cretaceous and prob- 

 ably there was much subsidence and elevation, and forms without 

 much vigor and adaptability might well have been externdnated. 

 The presence of several genera of two subfamilies in the Papuan re- 

 gion would agree with a hypothesis of long residence there and per- 

 haps of former residence in Austraha, when Papua and Austraha were 

 connected. The fact that gastrophrynids are now in southern Siam 

 Borneo, the Philippines, and Papua would indicate former spread 

 across the Malayan islands with later extermination in most of these 

 islands during the frequent late Tertiary fluctuations m this region 

 especially during the Pleistocene. The presence of several genera of 

 gastrophrynids in tropical America might be explamed by the com- 

 monly postulated Afro-American land connection usually thought to 



: See Hewitt. 1922, who suggests, for reasons not stated, that Ethiopia and Madagascar were again con- 

 nected for a brief period in the late Tertiary. 



