W. Lilljeborg on the Genera Liriope and Peltogaster. 59 



In the attachment of the old Peltogaster mlcatus, the inner 

 lamella of the skin of the Pagurus is strongly impregnated with 

 cement. The central aperture is closed by a layer of opake 

 and deep-brown cement, and the concentric striae surrounding 

 this aperture are far more distinct. The raised border of the 

 outer lamella is larger and more elevated, its colour is darker, 

 and its structure fibrous. 



The organ of adhesion in a fully- developed egg-bearing Pelto- 

 gaster sulcatus is bounded by a sinuous ring, which, with all the 

 parts placed within it, is of a brownish colour and much impreg- 

 nated with cement. An inner sinuous ring indicates the circum- 

 ference of the part which is fixed upon the skin of the Pagurus ; 

 it is situated upon a small neck, and forms the organ of adhe- 

 sion, strictly so called. The outer ring, which is a little raised 

 and resembles a cement-canal, sends inwards branches conveying 

 cement, and forms the outer boundary of a buckler which exists 

 in the skin and surrounds the neck of the organ of adhesion. 

 The margin of the part of the organ of adhesion at the lower 

 extremity of the neck is darker than the rest of the organ, and 

 from it numerous radiating lines of cement run towards the 

 centre. The central orifice is closed by cement. 



This mode of attachment proves that the Peltogaster, at this 

 stage of its development, no longer sucks its nourishment from 

 the Pagurus, the orifice through which the food must pass being 

 filled up with cement. Thus the functions of nutrition in these 

 animals must cease when they are completely developed. 



In a specimen 5 millim. in length the form was less elongated, 

 and the tube of adhesion shorter than in the two young indivi- 

 duals already described. The anterior extremity of the pallium 

 was closed. The ovaries were more developed, and distinctly 

 presented the form of two elongated ramose sacs. The testes 

 were scarcely perceptible. In another, 5^ millim. long, and 

 further advanced, the tube of adhesion was narrower, and its 

 margin, folded outwards, had begun to unite with the internal 

 tube, acquiring the ordinary form of the fully-developed adhesive 

 organ. The ovarian sac was very large, and contained distinct 

 ova ; the ovarian branches had become short, prominent lobules. 

 The anterior extremity of the body had a small orifice. 



Apeltes Paguri, nov. gen. et sp. 



This parasite (PI. Ill, fig. 6) nearly resembles Peltogaster 

 Paguri in form. It is 11 millim. in length and 3^ millim. 

 in thickness. It differs from all the preceding forms in the 

 structure of the part by which it is fixed upon the Pagurus. 

 Behind the middle of the lower part of the body (fig. 7) there 



