from a living Individual taken off Guernsey. 463 



ing communication in VI. 230, 231., from one of two individuals 

 captured on the coast of Cornwall by Mr. Couch of Polperro. 

 I have preferred giving a lateral view (fig. 39.), in order to 

 exhibit the various legs and processes beneath the body, and 

 the animal's usual appearance when in the water. 



In comparing my representation (Jig. 39.) with that pub- 

 lished in VI. 230., in illustration of Mr. Yarrell's communi- 

 cation, some differences will be seen, arising, perhaps, from in- 

 advertence on the part of the engraver. [We here repeat (fig. 



40.) the illustration published in VI. 230., and state that we 

 happen to know that it had been delineated from a dead and dried 

 specimen.] My specimen is full 3 in. long, which, I believe, 

 is something longer than those from Cornwall. [_Fig. 40. is, 

 Mr. Yarrell has stated in VI. 230., " the exact size of the 

 specimen, and measures 2 in. 4 lines in length."] Colour 

 greenish brown, mixed with yellow, somewhat transparent, like 

 a prawn. 



The four thoracic segments have on each side an oblate 

 depression close to the recurved margin. The abdominal 

 segments have two depressions on each side, divided by a 

 ridge: these become spinous on the fifth segment. In the 

 penultimate, the marginal line, or ridge, unites with the inter- 

 medial, curves over the base of the processes, and forms the 

 lower of the two lateral spines of that segment. There are 

 also two dorsal spines, making the number six on this segment. 

 It is in this segment [inj^. 40., and in the description in 

 VI. 231., it is represented to be from the caudal one] that the 

 articulated processes take their origin, which form, with the 

 caudal case, the fan-like termination of the bodies of the crus- 

 taceans of the order Macroura. The caudal case is termi- 

 nated by six spines, and is serrated in the spaces intervening 

 these, and is surmounted by a single dorsal ridge ending 

 abruptly on the upper side ; this ridge has a slight indenture 

 near the base, observable in all the species of this family, b, c 9 

 in fig. 39., represent the anterior arms, grooved on one side, 



