130 S. I. Smith — (Jrustaceans of the Atlantic Coast. 



The ditfereiices between the deep-water fauna? of the two regions, as 

 shown in this list, are probably wholly accidental, the species which 

 are not known to be common to both regions, being new or, at least 

 on the western side of the Atlantic, little known species which will, 

 most likely, eventually be found to inhabit both regions. 



The facts above presented show conclusively, I think, that, as far 

 as the Thoracostraca ai'e concerned, the fauna from Cape Cod Bay to 

 Labrador is essentially a continuous one, or at least that there are no 

 changes in it comparable with the dilierences between the fauna 

 south and that north of Caj)e Cod Bay. An uncompleted investiga- 

 tion of the disti-ibution of the Amphipoda sustains these conclusions, 

 which appear to be essentially in harmony with the facts at present 

 known in regard to the distribution of the Mollusca and of other 

 groups of the better known marine animals of the region in question. 



Of the fauna of the east, or Atlantic, and of the north coast of 

 Labrador, very little is at present known, but I believe no species of 

 crustaceans, which are not found also in the Gulf of St. Lawrence or 

 further to the south, have been recorded from this region, and the 

 very close resemblance between the fauna of the northern part of the 

 Gulf and that of the Greenland seas (to which I shall presently 

 allude) renders it very improbable that the fauna of the east and 

 north coasts of Labrador diifers essentially from that of the northern 

 part of the Gulf of St. Lawrence. The close relationship existing 

 between the marine fauna of Greenland and that of northern Europe 

 has long been observed and fully admitted by European zoologists, 

 but the similarly close relationship between the marine fauna of 

 Greenland and that of the coasts of the continent of North America 

 itself, as well as the similar relationship between the fauna of the 

 latter region and that of the seas of northern Europe, has not been 

 so generally recognized by them and has recently been streniTously 

 controverted,* This has probably been largely due to the fact that 



* Dr. J. Gwyn Jeffreys : Preliminary Report of the Biological Results of a cruise 

 in H. M. S. Valorous to Davis Strait in 1875, Proceedings Royal Society, Loudon, 

 vol. XXV, p. 188, 1876. 



The Rev. A. M. Norman, however, appears to have fully recognized the true rela- 

 tion between the fauna; of the eastern and western sides of the North Atlantic, and 

 also the American rather than the European character of the fauna of the Greenland 

 seas; and in this very report arrives at conclusions the reverse of those of Mr. 

 .leffreys. Mr. Norman has, in a letter received since these pages were written, very 

 kindly communicated to me his general conclusions in regard to the fauna of the 

 North Atlantic, and I am pleased to find that his investigations in nearly all the 

 classes of marine Invertebrata, have led to conclusions essentially the same as those 

 resulting from my special study of the Thoracostraca. 



