W. Lilljeborg on the Genera Peltogaster and Liriope. 163 



sion to refer to it. Professor Lilljeborg considers that Rathke's 

 Peltogastri belong to the group of Cirripedes, and admits the 

 generic divisions established in them by Diesing. 



Genus Pachybdella, Diesing, Syst. Helm. i. p. 435. 



Of this genus, which, as Leuckart has shown, is identical 

 with Sacculina of Thompson, the author gives the following 

 character : — 



Animal e Crustaceorum classe et Cirripediorum subclasse, ectopara- 

 situm sub abdomine Crustaceorum Decapodorum Brachyurorum 

 degens. 



Animal adultum crassum, sacciforme, transverse ellipticum, cute 

 (pallio) leevi, molli, sed firma, corpus crassum, carnosum, intus 

 glanduliforme et sine cavitate digestionis distincta, instar pallii 

 circumdante, vestitum. Os in organo adfigendi, vel acetabulo, 

 subinfundibuliformi, corneo perforatum, et in cesophagum trans- 

 iens. Anus nullus? Ovaria externa numerosa, ramosa, cseci- 

 formia, circa corpus adfixa et membrana tenui involuta. Ovaria 

 interna in corpore carnoso sita. Cavitas inter ovaria externa et 

 pallium per foramen sat magnum, ori oppositum et plicis cutis 

 circumdatum, aperta. Organa masculina ignota. 



Pullus entomostraciformis, pullo Cirripediorum processibus ad latera 

 partis anterioris corporis similis. 



The form of the young proves that these animals belong to 

 the Cirripedes. The mature animal is a sac without segments, 

 eyes, or limbs (PL IV. fig. 6). This sac presents two prominent 

 parts, of which the first, situated on the side by which the 

 creature is attached to the animal on which it lives as a parasite, 

 is a funnel-shaped organ of attachment (fig. 6 a), supported by 

 a short neck and perforated in the middle by the mouth. At 

 the opposite side there is a short tube, formed by folds of the 

 skin, and surrounding an aperture of considerable size; the 

 latter leads into the cavity containing the external ovaries, and 

 appears to be intended to give exit to the young. 



The oesophagus is small and short ; in the individual examined 

 by the author it was curved in a spiral form, and fixed to the 

 lower side of a large fleshy part. The latter had a glandular 

 appearance internally, and had no distinct digestive cavity ; the 

 author regards it as the transformed body probably occupied 

 for the most part by the generative organs. The voluminous 

 racemose interior ovaries were seen distinctly, but no male 

 organs were observed. This body was continued to the superior 

 aperture, where, however, it presented no anal opening, but its 

 thick outer coat forms the large folds which surround that ori- 

 fice. At one side the membrane enveloping the body appears 

 to be more compact, and furnished with several distinct folds, 



