126 



iS. I. Smith — Crustaceans of the Atlantic Coast. 



A simple summation of the columns of the above table gives the 

 following as the number of species found in the whole region under 

 discussion, and the number of these species recorded from the regions 

 specified : 



This summation, however, does not fairly represent the Thoracos- 

 tracan fauna of our northeastern coast, since it takes no account of 

 the rare or accidental occurrence of species outside their regular 

 habitats, and, in particular, because it takes no account of the occur- 

 rence of species, under favorable local conditions, far north and south 

 of their ordinary limits. 



As has been previously remarked, the faima of Oape Cod Bay is 

 an extension of the southern, or Virginian, fauna across Cape Cod, 

 and should properly be excluded from the fauna of the coast of 

 northern New England. Although the crustacean fauna of Cape 

 Cod Bay is very poorly represented in the previous list, the number 

 of species I'ecorded is sufficient to illustrate its southern character, 

 which is abundantly proved by the other classes of its inhabitants. 

 Of the eleven species recorded from Cape Cod Bay, the following 

 have not been recorded from elsewhere north of the Cape and do 

 not, in any sense, belong to the fauna of northern New England : 



Gelasimus pugnax. 

 G. pugilator. 

 Platyonichus ocellatus. 



Carcinus msenas. 

 Panopeus depressus. 

 P. Savi. 



U-) 



With the single exception of the apparently cosmopolitan Carcinus, 

 these species represent the extreme northern limit, on our coast, of 

 the genera to which they belong, and of the genera themselves none 



