NO. 



PARASITES METCALF 1 1 



flukes (Trematoda) and tapeworms (Cestoda) of mammals, birds and 

 frogs (quoted from S. J. Johnston 1913, 1914, 1916), from biting 

 lice (Mallophaga) of Australian and South American mammals, from 

 fresh water Crustacea and their worm parasites (Temnocephala). ^ 



Biting lice belonging to three dififerent groups, and which Harrison 

 suggested (1922) might well constitute a distinct family, occur upon 

 Australian and South American marsupials and South American 

 porcupines/ Harrison says : 



There is no evidence that these parasites have ever existed on other mammals 

 in more northerly lands, and it seems most probable that they would have left 

 residuals here and there if such had been the case. So here again the greater 

 probability lies with Antarctic connection between South America and Austraha. 



As to the freshwater crayfishes and their geographical distribution 

 (Australia, New Zealand, Madagascar, South America, with one 

 "northward wanderer" in Cahfornia), Harrison writes: 



This is a case in which parasites can be used to aid us. The four southern 

 groups of crayfishes^ all carry ectoparasitic temnocephaloids, a group generally 

 associated with the monogenetic trematodes [flukes], though differing from these 

 in certain important features. They are confined to fresh water, and are para- 

 sitic on the following hosts other than crayfish: tortoises (Brazd), shrimps 

 (Argentina), molluscs (Brazil), crab (Matto Grosso) ; shrimps and an isopod 

 (Australia); Crustacea (Java to Philippines). In addition, one species has 

 apparently succeeded in reaching the northern crayfishes at their southern limit, 

 Tcnmoccphala mexicana being recorded from Cambarus digniti of Mexico. 



From the greater variety of hosts upon which they are found in South 

 America it would seem that the Temnocephaloidea were evolved there, becoming 

 parasitic upon the ancestors of Parastacus, and were carried with the migrating 

 Crustacea to Antarctica, New Zealand, Australia, and Madagascar (perhaps by 

 way of the Molluccas and Seychelles, as has been suggested for many other 



animals). , , , , 1 1 -^ 



If crayfish had ever existed in Africa, they must have had temnocephaloid 

 parasites, since the Malagasy genus Astacoidcs has them, if it be presumed 

 that the latter were derived from the former. It would follow that the Holarctic 

 crayfish must have had these parasites. If so, where are they now? It is 

 too much to ask us to believe that they have become extinct m the northern 

 temperate zone when we find them so widely spread and holding their own in the 

 southern. There is no evidence that crayfish have ever existed m the tropical 

 belt and the fact that their place is filled there by other creatures, such as fresh- 

 water crabs, and giant prawns, seems to indicate positively their non-existence 

 at any time. 



In 1926 Harrison again discusses Antarctica as a center of radiation 

 for plants and animals, using host-parasite data as " crucial evidence." 



^The porcupines are a peculiar group whose relationships to other rodents 

 are not understood. It would be especially interesting to know what, if any, 

 Mallophaga are found on African porcupines. 



^ Geographical, not taxonomic, groups, in the four lands named above. 



