14 Pratt, Marine Fauna of the Falkland Islands. 



and Microporella ciliata occur fossil, and might be rem- 

 nants of a once universal fauna. Evidence shows that 

 these forms have been able to withstand all changes of 

 temperature and altered conditions of life, without either 

 becoming extinct or undergoing modification so far as 

 the hard parts are concerned. 



Smittia. The genus appears to be cosmopolitan. It 

 is found among the fossil tertiary deposits. It inhabits 

 shallow and moderately deep water, the greatest recorded 

 depth being 600 fath. (vS. sniittiand). 



Smittia landsborovii appears to be characteristic of 

 north and south temperate and cold seas, from shallow 

 water to great depths. Fossil : Scottish glacial deposits. 



The species S. trispinosa occurs in temperate and 

 tropical zones, in shallow water and at great depths. 



Porella. The genus is cosmopolitan, and is represented 

 in the tertiary deposits. It occurs in shallow water chiefly, 

 but does also occur at moderate depths. 



These results, as far as the Bryozoa are concerned, seem 

 to support Murray's theory on geographical distribution. 



Each genus represented in the collection occurs fossil, 

 and also occurs in the north and south temperate zones, 

 as well as in the tropics ; in fact, most of the genera are 

 cosmopolitan. 



Many of the species are represented in the tertiary 

 deposits. This shows that the changes of climate and 

 altered conditions of life, have not affected their "tertiary" 

 structure ; as many of these forms occur only in the two 

 temperate zones, there is reason to believe that they have 

 retained their common ancestral structure. 



The fact of many of the species occurring in the 



