320 On a new genus and some new species of British Crustacea. 



each of which exists a notch or depression which is increased in 

 the fourth and fifth abdominal rings, which do not terminate in 

 a tooth-hke projection. 



There also exists a lateral ridge on both sides, which, com- 

 mencing at the fifth thoracic ring, terminates with the fourth 

 abdominal ring where it becomes confluent with the carinated 

 edge. 



Lower and upper antennae short, equal in length, the peduncle 

 of each consisting of thi'ee articulations. 



Taken in Langland Bay, Swansea, at low water mark. 



To designate this species, I have adopted the name of M. Mog- 

 gridge, Esq., of Swansea, whose industry as an obsei'\er of na- 

 ture is indefatigable. 



Pagurus Dillwynii. PI. X. fig. 11. 



Carapace smooth and polished. Colour bluish, marked with 

 brown. 



First pair of feet unequal, the left being much longer than the 

 right ; smooth to the naked eye, but under a lens perceived to 

 be minutely granulated. The second and third joints are armed 

 with teeth, which give to the limb an angular character. The 

 right is very short and covered with hairs. 



The external antenna is about two-thirds the length of the 

 longest of the first pair of feet,'and hairy ; its base as long as the 

 eye- stalks, which are slender and long. The basal tooth with 

 which the antenna of this species is generally armed, is wanting. 



The false feet in the female are long and feathery, and divide 

 at the base. 



The most striking difference between this and other British 

 species of the Paguridce is exhibited in the form of the first pair 

 of feet and the length of the external antennae. 



Having met with only this solitary specimen, it is impos- 

 sible to say but that the right foot of the first pair, which is 

 usually the longer, may be in the process of being reproduced 

 from loss ; although I am inclined, from its well-developed 

 character, to believe that the left is in this species the more im- 

 portant of the two. The false feet, which in the female are 

 generally forked, are so in this specimen, but very much nearer 

 to the base than in the common species. 



It burrows very rapidly in the sand. Taken near the Worms 

 Head, Swansea. 



Mr. Couch has informed me, since this has been in the hands 

 of the printer, that he has also found the species in Cornwall. 



The name applied to this species is one long known to science, 

 and honoured as the stimulator of natural history in this locality 

 in the person of L. W. Dillwyn, Esq., Sketty Hall. 



