OF SOUTH DEVON. 291 



Order II. — Crustacea Stomapoda. These have their bran- 

 chiae exposed and adherent to five pairs of appendices, situ- 

 ated under the abdomen (the tail) ; their shell is divided into 

 two parts, the anterior of which carries the eyes and interme- 

 diate antennae, or forms the head, without bearing the jaw- 

 feet ; these organs, as well as the four anterior feet often ap- 

 proximate the mouth in two converging lines ; hence the 

 name Stomapoda. 



Family 1. Unipeltata, single-shelled Stomapods. 



Genus SQUILL A. 



Squilla, sub-genus. 



S. Desmarestii. We have a good specimen in our Museum from Jersey. 

 Mr. Couch has found it also at Polperro, which, being very near us, I 

 have no doubt that future investigation will find it on our coast. 



MALACOSTRACA with sessile, immoveable eyes. 



Order III. — Crustacea Amphipoda are the only Malacos- 

 traca of this division, whose mandibles are provided with a 

 palpus, or whose sub-caudal appendages resemble false or fin 

 feet, by their cilia, &c. ; in the following orders these parts 

 are laminae or scales ; these cilia or hairs appear to consti- 

 tute their branchiae ; many have vescicular pouches between 

 their feet, the use of which is unknown ; the antemice, mostly 

 four in number, are advanced, terminating in a point ; body 

 compressed and curved posteriorly ; appendages of the tail 

 resemble small articulated stylets ; most of them swim and 

 leap with facility, always on one side. 



Genus GA MM AR US. 



Section 1. Those with fourteen feet, all ending in a hook 

 or point. 



Division 1. Uroptera. 



Hyperia, sub-genus. 



H. (Cancer Gammarus monoculo'ides, Mont. * Linn. Trans.' xi.) 



Phrosine, sub-genus. 



P. (Can. Gam. Galba. Mont, 'Linn. Trans.' xi.) Plymouth Mu- 



seum. 



Division 2. Gammarince. 



Ione, sub-genus. 



I. thoracica, (Oniscus thoracicus, Mont. ' Linn. Trans.' ix.) found on the 

 Callianassa subterranea t * Edinb. Enc' vii. 406. 

 Orchestia, sub-genus. 



O. littvrea, (Can. Gam. littoreus, Mont. ' Linn. Trans.' ix.) Plymouth 

 Museum. 



