W. Lilljeborg on the Genera Peltogaster and Liriope. 167 



the Cirripedes. During the development of the ova the ovaries 

 become enlarged, until at length they fill the whole cavity of the 

 body, and at the same time they unite so closely, or even become 

 so confounded, that it is sometimes impossible to discover their 

 original limits. They then present the appearance of a single 

 sac surrounded externally by the inner membrane of the body- 

 cavity. When the skin is removed, the sacs of eggs appear as a 

 single sac, the walls of which are formed by the membrane which 

 lines the cavity of the body, but beneath this they are found to 

 possess their own proper coats. These walls are less transparent 

 and solid, cellular in structure, and contain formative substances, 

 from which it follows that the sacs themselves act as matrices, 

 and not the cavity of the body as supposed by Rathke. When 

 the membrane enveloping the ovisacs bursts anteriorly, the 

 young escape directly by the anterior aperture of the body- 

 cavity. Probably the existence of the parent terminates with 

 the accomplishment of its propagative destiny, as in other para- 

 sites; and thus we may explain the transformation of the ovaries 

 into such enormous sacs. The author found two specimens of 

 Peltogaster sulcatus, dead and completely empty, but still attached 

 to the abdomen of Pagurus chir acanthus, Lillj. He has also found 

 in the same matrix ova and newly-hatched young; it therefore 

 appears that the development of the eggs does not take place 

 simultaneously, although the difference is not great. 



The organ of adhesion, being generally in the form of a funnel 

 with a neck of greater or less length, is always of a harder tex- 

 ture than the surrounding skin, and more or less horny accord- 

 ing to the age of the animal. Young individuals, in which the 

 secretion of cement has been less, have the organ softer and 

 lighter in colour ; in older specimens it is hard and solid, at 

 least in part, and its colour is then brown*. It has always an 

 aperture in the middle (fig. 8), through which the Peltogaster 

 probably sucks its nourishment from its host. This orifice is 

 continued through the neck of the organ of adhesion, and also 

 through the epidermis and dermis. Rathke denies the existence 

 of this aperture, believing that the orifice at one extremity lead- 

 ing into the cavity of the body was the mouth. But the form 

 of the organ of adhesion and the mode in which it is attached to 

 its host appear to prove that it is formed, as in the other Cirripedes, 

 at least partially, by the secretion of cementf. As in the other 

 Cirripedes, it appears that this organ is also formed by a trans- 

 formation of the outer or second pair of antennse, formed in the 



* The substance of which it is formed is probably chitinous. 



t In a specimen of P. Paguri, the author once observed a portion of a 

 canal attached by one of its extremities to the inner part of the epidermis; 

 this might have been a cement-canal. 



