INTRODUCTION. '\V 



and a still smaller number in a south-easterly direction 

 (Hastings). These give a peculiar interest and charm to 

 tin- marine fauna of Devon and Cornwall and the Channel 

 Islands. Amongst them may be named Mimosella gracilis, 

 Lichenopora radiata, Diastopora Sarniensis, Entalophora 

 cl a riff a, Retepora Couchii, Lepralia adpressa, Lepralia 

 foliacea*, Schizotheca fissa, Smittia cheilostoma, Schizo- 

 porellu Cccilii, S. sanguined, S. vulffaris, S. armata, S. 

 rciuista, Diporula verrucosa, Cribrilina Gattyce, C. figularis, 

 Microporella violacea, Caberea Boryi. 



Other southern forms extend much further north ; and 

 a small group occurs in the Shetland seas. A very limited 

 number have found their way to the north-east of Scot- 

 land and England ; and in similar cases Mr. Norman has 

 shown it to be probable that migration has taken place along 

 the western and northern and down the eastern coasts f- 



The north-eastern district is characterized by the pre- 

 valence of Arctic and boreal forms, and the absence for the 

 most part of distinctively southern species, even of such 

 as have found their way as far north as Shetland. 



Amongst the British Polyzoa we find a number of 

 erratic species having a wide and somewhat anomalous 

 range. For instance, Cellaria fistulosa has occurred in 

 the Mediterranean and at Madeira, in South Africa, in 

 Scandinavia and North America, in the Indian Ocean, 

 in Australia and New Zealand. Microporella ciliata, 

 another cosmopolitan form, ranges to Florida, California, 

 the Arctic seas, Scandinavia, South Africa, the Arabian 

 sea, A lifted ia, and New Zealand. M. Malusii has been 

 found in the Arctic seas, Scandinavia, the 15Iark Sea, the 



* L. foliacea haa occurred in (he Hi-hnl.-. 



t Bugula tiirf'inafa is probably u southern form which has thus made it* 

 way to the Durham and Yorkshire coasts. 



t'2 



