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. Lovén 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. chiracanthus, on the coasts of Norway 
and Sweden. It usually occurs singly on the abdomen of the 
Pagurus. 
