CRUSTACEA OF NORTHUMBERLAND AND DURHAM 



made tlieir way thither round tlie western and northern, and 

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

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

 example Cerithinm perversuui, Phasiauella ptilla, Fissitrella 

 gf'ceca, Tellina balaustina, Calliaiiassa suhterranea, Palmipes 

 placenta, Aiiiphhira brachiafa, &c., have been found in tlie 

 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 Plenrotoina sfriolata, attennata and septaiigitlaris, 

 Cerethiopsis tuheradaris, Cerithiuni reticulatiim and perversvvi, 

 Rissoa violacea, Pholas dacfylus, Solen vagina, Psamnwbia 

 costiilafa, Gasfrana fragilis, Isocardia cor, Car din in aciileafum, 

 Lepton sqtianwsuni, Xanflio rivnlosus,,Poriuniis arcvatus, Gcbia 

 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 



* Norman (A. M.) " Last Report of Drcc%iug- among- the Shetland Isles," Rep. 

 Brit. Assoc, (for 1863), ItGO, p. 218. 



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