ETJPAGURTJS . 503 



The Thoracic epimera form the inner wall of the 

 branchial chamber and support the gills. The whole 

 constitutes a thin, slightly calcified plate, grooved 

 between the segments by vertical sutures. The inturned 

 edges of the epimera at these grooves form part of the 

 endophragmal system. 



The Abdomen of the Hermit Crab is quite unique 

 among the Malacostraca. It is a distended sac, which 

 might perhaps be described as banana shaped, into which 

 the gonads, digestive glands and renal bladder have been 

 crammed. The first segment (or peduncle) is small and 

 narrow and calcified. The last segment and its appen- 

 dages is also calcified, but the remaining four segments 

 are represented by an ungainly membranous bag, which 

 shows practically no trace of division into somites. 

 Traces of the terga can be distinguished above each 

 pleopod on the left side, and in a corresponding position 

 on the right (fig. A, PI. I). They can barely be seen in 

 young specimens and less in males than females. The 

 position of these remnants shows that the fifth segment is 

 greatly and the fourth rather elongated. Mention should 

 be made of the prominent " columellar " muscle on the 

 third segment. It seems to have only a passive function 

 in fitting the body more closely to the shell. 



Appendages (PI. II). 



The appendages of Ewpagurus bernhardus bear very 

 obvious marks of the asymmetry which affects the whole 

 animal. There is always (in the present species) a 

 striking inequality between the chelae, and of the 

 abdominal appendages only one, the uropod, has survived 

 on the left side. The walking legs, head appendages and 

 maxillipedes remain symmetrical. 



