THE CRUSTACEA 



137 



where the bottom was a rather fine gravel composed of 

 crystals of black hornblende and whitish felspar (the 

 rocks around being a gabbro). In these specimens the 

 markings consisted of dots and dashes of black on a white 

 ground, in imitation of the gravel, only that the markings 

 were symmetrically disposed, right and left (see Fig. 53). 



Fig. 53 Cranyoit tm/garix. A. Type, and a portion of sand bottom ; 

 B. Variety marked to imitate diorite gravel, portion of gravel 

 bottom also shown, f Natural size 



Crangon trispinorus is a smaller species, about an inch 

 long. It is distinguished by the presence of three sharp 

 spines on the front of the carapace. It lives in gravelly 

 situations. Its colours are as those of the common form. 



Crangon sculptus is a very beautiful little shrimp, about 

 the size of the last. This has the whole of the shell incised 

 in regular pattern. It is rare. This also lives in gravelly 

 situations. 



Crangon fasciata, The " Banded Shrimp " is a robust 



