CRUSTACEA OF NORTHUMBERLAND AND DURHAM 257 



made their way thither round the western and northern, and 

 down the eastern coasts to their present habitat, and not up 

 the eastern coast, as at first might have been supposed. For 

 example Cerithmm perversum, Phasianella piiUa, Fissurella 

 gnvca, Telliua balaustiua, Callianassa subterranea^ Pabnipes 

 placenta, Aviphhtra brachiata, &c., have been found in the 

 Moray Firth, but are wholly absent on the east coast of 

 England. Moreover many species have been recorded on 

 the Norwegian coast though never found on the eastern 

 shores of England, and therefore may be presumed to have 

 migrated thither up the western side of Great Britain and 

 round the north of Scotland \ as examples of such species 

 may be cited Pleurotoma striolata, attenuata and sepfangulan's, 

 Cerethiopsis fuberailan's, Cerithium reticulatum and perverstim, 

 Rissoa violacea, Pholas dactylits, Soleii vagina, Psamtnobia 

 costiilata, Gash'ana fragilis, Isocardia cor', Car-dinm aciileatuni, 

 Lepton squamosum, Xantho rirulosus, Portuntis arcuatus, Gebia 

 deltura, &c. On the other hand, while northern forms do not 

 extend southward on the east coast beyond Yorkshire and the 

 Dogger Bank, on the western coast they in many instances 

 have a range southwards to the Nymph Bank off Cork, and 

 even to the Mediterranean Sea."* 



Forty years have elapsed since the above was written, and 

 a continued study during that time of the distribution of 

 animal life in the North Atlantic has fully confirmed the views 

 expressed by the writer in the foregoing extract. If re- 

 written now a few names therein quoted as Norwegian would 

 be struck out as erroneously recorded ; but the writer would 

 on the other hand be able to add a large number of other 

 species as illustrative of his views. Moreover he has during 

 these years been able to establish a remarkable fact. It is 

 that during the last months of the year, as also during the 

 first months, that is apparently from November to March, 

 enormous quantities of free swimming animals are often 

 brought down from the north along the coasts of Scotland 



* Xoi-man (A. M.) " Last Report of Dredging among the Shetland Isles," Rep. 

 Brit. Assoc, (for 1868), 1869, p. 248, 



