582 Transactions of the Society. 



SUMMAKY OF RESULTS. 



Bdelloida : forty-one species were identified, fifteen in the North 

 Island, forty in the South Island, and four in Stewart Island. 

 Three new species are described. The South Island was very much 

 more productive than the others. Only one form, a peculiar variety 

 of P. brycei, occurred in the North Island and not in the South. 

 This is the only form of Bdelloid observed by us which is not 

 known elsewhere. Two of the new species here described were 

 afterwards obtained in Australia ; one was previously known in 

 Scotland. Two of Hilgendorfs species (P. cloacata and C. quadri- 

 dens) are the only species of Bdelloida recorded for New Zealand 

 alone. 



There were ten Bdelloids previously known in New Zealand, 

 only one of which (R. vulgaris) occurred in our collections, so that 

 forty species are new records for New Zealand, making the list of 

 known Bdelloida up to fifty. 



The most noticeable features of the Bdelloid fauna of New 

 Zealand are its close resemblance to that of temperate Europe and 

 the great scarcity of peculiar forms. In such an extensive, remote 

 and varied country these facts are very remarkable. 



But for five names, our collection might have been made in 

 Britain ; there are only four species not recorded for Europe. And, 

 moreover, there are few rare species among the thirty-six which are 

 common to Britain and New Zealand. These facts strongly sup- 

 port Mr. Rousselet's contention (9) that each species of rotiferon 

 is cosmopolitan, wherever suitable conditions prevail. Jennings 

 earlier (6) stated the same thing in general terms. It might be 

 better to express the fact by saying that the limits of distribution 

 are determined by conditions, since, if climatic conditions exclude 

 some species from great zones of the earth, they cannot be called 

 cosmopolitan. 



I believe, however, that the case of New Zealand, so strongly 

 supporting the theory that similar climates have similar Rotifer 

 faunas, is exceptional, and that other factors must be considered. 

 All the continents, so far as they have been examined, show greater 

 peculiarity than New Zealand. Canada, with a climate so like 

 that of Northern Europe, has many Bdelloids not known in Europe. 

 Temperate South Africa, with a climate sufficiently like that of 

 New Zealand, lias many peculiar Rotifera. 



The apparent poverty of the Rotifer fauna of New Zealand 

 must be regarded along with its resemblance to that of Europe. 

 The poverty in peculiar forms is especially marked. North America 

 and Australia, though only partly worked, have longer lists of 

 Bdelloids, and more peculiar species. Even Britain has many 

 Bdelloids not known elsewhere. 



