170 W. Lilljeborg on the Genera Peltogaster and Liriope. 



ally in young individuals. The epidermis, which is particularly 

 transparent, appears to be generally raised a little above the 

 dermal layer. On the lower surface is an elongated area in 

 which the skin is less transparent, probably in consequence of 

 the thickness and opacity of the inner skin. The four older and 

 larger specimens lent to the author by Prof. Loven were filled 

 with ova, and had the posterior part of the body a little less 

 narrowed than the other specimens. In three of them there 

 were little spines at each extremity of the body (fig. 13) ; but these 

 were wanting in the fourth and largest specimen, so that they 

 cannot be regarded as characteristic of the species. In other 

 respects the four specimens were exactly alike, and they were 

 found upon the same species of Pagurus (P. cuanensis), and in the 

 same locality. The organ of adhesion (fig. 8) is larger in this 

 species than in the others, and also differs greatly in two respects : 

 in the first place, it is fixed in this species upon a dilated cor- 

 neous and elongated shield, having the two extremities obtuse 

 and placed upon the middle of the lower part of the body ; 

 secondly, its margins are more dilated, and become dispersed in 

 several branches, which are by degrees confounded with the 

 external skin of the Pagurus. The shield extends only a little 

 upon the lower surface of the body. In older individuals, the 

 corneous matter of which this organ is formed is found to be 

 more solid and darker in colour; the shield in these is also 

 larger. In young individuals the central solid and dark part 

 of the shield is surrounded by some clear concentric streaks, 

 which, although they differ from the epidermis, have not yet 

 acquired the solidity of the central part. The shield is therefore 

 formed by an addition of new concentric layers of cement round 

 the central layers, as well as by an addition of cement to the 

 latter. There is also a small hollow neck between the shield 

 and the acetabulum, of the same substance and colour as those 

 parts (fig. 8 a). This neck is visible above the skin of the 

 Pagurus. 



The orifice at the anterior extremity of the body leading into 

 the internal cavity is placed nearly in the middle of that extre- 

 mity, which is the most obtuse. The size of this aperture and 

 the number of folds of skin surrounding its tube are subject to 

 variation. The same membrane which lines the cavity of the 

 body also lines the interior of the tube. 



The colour is variable : in some it is yellowish -green ; in 

 others, filled with well-developed eggs, reddish. 



This species has been found on Pagurus Bernhardus, P. pu- 

 bescens, P. cuanensis and P. chir acanthus, on the coasts of Norway 

 and Sweden. It usually occurs singly on the abdomen of the 

 Pagurus. 



