i 



GEOGRAPHICAL DISTRIBUTION OF CRUSTACEA. 1503 



The species of Cancrinea of the Torrid zone section, which reach 

 farthest into the Temperate zone, are those of the following genera: — 

 Xantho, which has eight Temperate zone species out of twenty-eight 

 in all; Panopeus, which in the same way has four out of ten; Pilamnus, 

 which has seven out of twenty-two ; and Lupa, which has four out 

 of ten. The Cold Temperate Region is the highest for each of these 

 genera, excepting Lupa and Pilumnus, a species of each of these latter 

 genera extending just within the limits of the Subfrigid Region, on 

 the coast of Massachusetts. 



XII. The Grapsoidea, if divided between the Torrid zone and Tem- 

 perate zone, according to families or subfamilies, will fall within the 

 Torrid zone, excepting a single family of the Pinnotheridse, which 

 contains eight species in the Torrid zone and fifteen in the Temperate. 

 Considering the genera, however, we find that several among the 

 Grapsidae may be called cold-water genera, or are about equally 

 divided between the Torrid and Temperate zones. They are as follows : 



Pseudograpsus, ..... 



Heterograpsus, ..... 



Brachynotus, ..... 



Planes, ...... 



Hemigrapsus, ..... 



Cyrtograpsus, ..... 



Chasniagnathus, . . . 



Five out of twelve species of Grapsus also reach into the colder 

 seas. Further particulars will be gathered from the tables. 



XIII. The Leucosoids include as cold-water genera the following : 



Torrid 



Temperate 



species. 



species. 



1 



2 







1 







1 



2 



2 



4 



5 







1 



2 



2 



Torrid. 







Temperate. 



8 







1 



Genus Ebalia, ..... 

 " Ilia, ...... 



The remaining genera are mainly confined to the Torrid zone ; out 

 of the species they contain, sixty-seven in all, forty-eight are of this 

 zone. Hepatus, however, contains as many cold-water as warm-water 

 species, and the same is true of Dorippe, although but one of the 

 species of the latter is exclusively Temperate. 



XIV. The tropics afford not only a larger number of species of 

 Brachyura than the Temperate zone, but also a much greater propor- 



