32 DULICHinXE. 



The inferior antennas are shorter than the superior, 

 reaching scarcely to the extremity of the peduncle of the 

 superior. The first pair of legs have the hand small, 

 short, and oval, the pajm being oblique and imperfectly 

 defined. The second pair of legs are much larger than 

 the first, and have the hand long, but not very broad. 

 It is armed anteriorly and inferiorly with two long, 

 straight teeth, directed forwards, the posterior being the 

 longer. The finger is short, thick, and double-lobed 

 upon the inner margin. The coxae of the second pair of 

 legs are produced in front to a point. The caudal 

 appendages are sub-equal, and the middle tail-piece is 

 pointed. 



We first received this specimen from Mr. Gregor, of 

 Macduff, who procured it from the Moray Frith, and 

 subsequently from Dr. Walker, who took it in deep 

 water between the rivers Dee and Mersey. 



The specimens received from Dr. Walker differ from 

 the type of the species so much that we hesitated in con- 

 sidering them identical. After full consideration, how- 

 ever, we feel assured that the alteration of form is one of 

 variation, dependent upon some altered conditions in the 

 history of the animal. 



The specimens from the mouth of the Dee have the 

 hand of the second pair of legs shorter, stouter, and more 

 oval than in the type, but the armature is the same, except 

 that the inferior tooth is not quite so far behind the 

 first, and not directed so straight forwards. 



One of these specimens was a female, and, fortunately, 

 the larva were in a mature condition, which enabled us 

 to ascertain that the absorption of the seventh into the 

 sixth segment is a feature from the earliest existence of 

 the animal. The larva is distinguishable from the adult 

 by the shortness of the antennae, the small sizes of the 

 hands, and the shortness of the last pair of legs. 



