246 



Mr, J. R. Tosh on an Abnormal Crab. 



part of the fourth, and the tip of the sixth being visible above 

 the ventral part of the carapace. The first joint alone was 

 normal in size, the next two were a little less than normal, 

 the next two five times and the last two six times less than 

 normal. The dactylopodite was not opposable to the beak of 

 the protopodite, but curved downward into the branchial 

 cavity as a more or less rigid process. It had apparently taken 

 the direction of least resistance. It bore no serrations. The 

 same blackish hue occurred at the tips of dactylopodite and 

 protopodite as in those of the functional chela. All the arti- 

 culations in the limb were more or less immovable. The 

 specimen was an average-sized female, and, to judge from the 

 state of the ovaries, which were nearly ripe, had suffered very 

 little from the condition of the claw. In the figure the dotted 

 line represents the posterior edge of the shell, which has been 

 removed to show the limb. It may be supposed that at the 

 last moult this chela had been injured in some way, probably 

 a few joints knocked off, and that, before it was restored, the 

 shell had overgrown and imprisoned it: certainly it has 

 never been functional. 



Srd mxpd. 

 dact. 



iBt walking 



Richard describes a number of cases of abnormality in crus- 

 tacean appendages. These fall into two classes : the first 



