BRACHYURI. 201 



§ 5. Cancer horbidus, Maia lithodes.— The Prickly Crab. — 

 Plates LI., LII. 



The appearance of the Prickly Crab, or at least of its important 

 parts, will be best understood from its name. Dr Leach has prefixed 

 half a dozen synonyms to his description of the animal ; but as we do 

 not intend to overload this treatise with nomenclature, they may remain 

 where he has left them. 



Were the size of a li^^ng creature to be computed by the space 

 which its parts can actually cover, this would be distinguished as the 

 largest of the crabs belonging to the Scotish seas, and its appearance is cer- 

 tainly the most singular. The length of the shell of the finest specimens, 

 from the base to the extremity of the rostrum, is about six inches, and 

 the extreme breadth four and a half, being wholly of a triangular shape. 



The limits expand no less than twenty-two inches between the op- 

 posite extremities, the longest being the second pair, but they are not 

 proportionally strong. 



Only six limbs are prominently visible ; the hind pair, much the 

 smaller, are concealed under the edge of the shell from their origin. 

 Great disparity subsists between the size of the two claws, the largest 

 extending seven inches from the root. The rostrum terminates in a 

 solid fork, while the antennge stretch above two inches. 



This species is totally covered by large and strong prickles, like 

 thorns, some extending above an inch, which, were not the animal of 

 very pacific nature, might prove it a most formidable enemy, yet it seems 

 quite the reverse. 



Here the apron of the female is very large, and of peculiar texture, 

 flexible, and of consistence somewhat resembling sheepskin leatlier, yield- 

 ing to pressure of the finger. 



A singular cavity penetrates the shell, which is adapted for receiving 

 the swelling spawn. This, during the month of January, is composed, in 

 its earlier state, of a vast congei-ies of slender threads. The apron of the 

 female resembles a portion of wood or other sohd substance, curiously 

 sculptured in regular and irregular figures. 



2c 



