NO. 8 PARASITES — METCALF 2/ 



also it is still more fortunate. This cannot be expected in many cases, 

 but there is prospect of some success in such study of bones of 

 Vertebrata and their lesions (Moodie, 1923; Rupper, 1921), of 

 conifers and their distortions caused by Peridermiums and My- 

 corrhizae, of some other plants and their scars from fungus diseases, 

 of many plants and their insect galls and probably of still other groups 

 of animals and of plants showing fossil records of parasites. 



This paper may well close by suggesting as samples one or two 

 special problems favorable for attack by the host-parasite method. We 

 have already noted crucial data presented by parasites of several 

 groups as to the problem of. east and west routes of dispersal in the 

 Southern Hemisphere. The parasites of both plants and animals which 

 show families, genera, and especially species, common to different 

 southern lands, and southern lands only, may well be studied further. 

 Such studies should finally determine not only the question of the 

 former existence of such east and west migration routes, but also their 

 position, their connections and their geologic time. On the other hand, 

 if in some groups the dispersal was southward from northern lands, 

 this fact will be demonstrated beyond dispute. Let us note here a 

 partial list of species, genera, and families of southern occurrence 

 whose parasites of all kinds should be studied (c/. figs, i, 2 and 3). 



Mammalia 



The marsupials of Australia and of America (mostly tropical America). 

 Their biting lice (Mallophaga) have been somewhat studied, so 

 also their flukes (Trematoda) and tapeworms (Cestoda). 

 The porcupines (Hystricomorpha) of America (mostly tropical America) 



and of Africa. 

 Edentata (sloths and anteaters) in South America, South Africa, southern 

 India, Malaysia. 

 Birds 



Struthiornidae (ostrich family) with species — 2 in New Zealand, 2 in 



Australia, I in Papua, 2 in South America, I in Madagascar. 

 Trogonidae (the quetzal and its relatives) in South America, Central Amer- 

 ica, Africa, and southern India. 

 Chionidae (sheathbills) Antarctic Islands 

 Psittacomorphae (parrots) in the Southern Hemisphere, with "stragglers" 



in North America and some in India. 

 Paristeropodes (a group of fowls) in Australia and South America. 

 The Ocydromine Rallidae (rails) 3 in Australia, Hcterochloa in New 



Zealand and also in Madagascar. 



Avocets and stilts in Australia, New Zealand, South America and Africa. 



Penguins in Australasia (including New Zealand and its Antarctic islands), 



South America, Africa, Antarctica, Antarctic islands in general, 



including St. Paul in the Indian Ocean. It is interesting to note 



