372 GAMMARID^. 



the palm is oblique, and not clearly defined. The second 

 pair are about the same size as the first, but the palm 

 of the hand is less oblique and better defined. In the 

 female the hands are rather shorter and more ciliated. 

 Some of the hairs on the wrist of the first pair are 

 fringed with cilia, while those on the wrist of the second 

 pair are three-pointed, those on the hand are subapically 

 furnished with a single cilium. The thighs of the last 

 three pairs of legs are dilated, but the posterior margins 

 are subparallel with the anterior. The last pair of 

 caudal appendages are considerably longer than the two 

 preceding pairs, and have one branch long, and one about 

 one-quarter of the size of the other.* The central tail 

 appendage has each division tipped with a bundle of 

 spines of the same form, with the exception of one, as 

 all the others on the tail ; this one is finer, and crowned 

 with a small plumose brush. 



The structure of the skin, when viewed under the 

 microscope, exhibits traces of its cellular origin ; it is 

 also perforated by numerous round hol- 

 lows or pores, and a quantity of minute 

 finely -pointed equidistant cilia, arising 

 from bulbs of a somewhat hour-glass 

 form, that is, being larger at each ex- 

 tremity than at the centre, as seen in the 

 annexed figure. 



The colour of the animal is of an olive-green, deepest 

 along the dorsal margin, and verging to a buff at the 

 extremities. Sometimes in a large group, for they are 



* Burgersdyck (Annotationes, &c., p. 17) confounds tliis minute brancli 

 with the terminal central bifid tail-piece ; and, from want of specimens of 

 the true 0. marinus, supposes Leach to have erred in his description of the 

 head of the present species. 



