W. Lilljeborg on the Genera Peltogaster and Liriope. 173 



appendages (which have completely disappeared in Pachybdella) 

 are removed. In Pachybdella, as in the Cirripedes in general, 

 there are external and ramose u ovarian cseca " situated between 

 the mantle and the body [thorax). In external form it does not 

 differ much from the male Cryptophialus of Darwin*. The state 

 of Peltogaster is quite different. The external covering of the 

 body, or the skin, may be compared with the mantle of the ordi- 

 nary Cirripedes, having a second aperture as in Pachybdella. 

 But this mantle does not surround a separate fleshy body, and 

 it only contains a cavity lined with a delicate membrane. In 

 this cavity are sometimes accumulated the food which the animal 

 has probably sucked from its host ; and on the bottom of it there 

 are the two sacciform primitive ovaries, which become inflated 

 as they are developed, until they present two sacs of eggs com- 

 pletely filling the cavity. As there are analogies between Pa- 

 chybdella and the normal Cirripedes, others may be found 

 between Peltogaster and the abnormal Cirripedes, such as Dar- 

 win's Proteolepas. The external form of the latter has much 

 resemblance to that of Peltogaster, except that it has the body 

 segmented. Like Peltogaster, it has no distinct stomach ; and 

 almost the whole cavity of the body is occupied by a large sac 

 of eggs (perhaps by two). Outside this sac there are also two 

 sacciform ovaries, resembling the two primitive ovaries of Pelto- 

 gaster. From these comparisons it is evident that {{Pachybdella 

 and Peltogaster are to be regarded as inferior to all the other 

 Cirripedes, and consequently to all other Crustacea, Peltogaster 

 is the lowest of all. 



They appear generally to show the greatest affinity with the 

 order Apoda of Darwin ; but the segmentation of the body, the 

 appendages of the mouth, and the certain degree of permanence 

 of the prehensile antennae in the Apoda, distinguish them from 

 Peltogaster and Pachybdella. To the latter the author gives the 

 name of Cirripedia Suctoria, from their sucking their nourish- 

 ment from the animal to which they are attached. If the Cirri- 

 pedia be placed in a line parallel with the other Crustacea, the 

 Cirripedia Suctoria must be regarded as analogous to the Ler- 

 nceidce amongst the latter. 



* The internal structure of Cryptophialus appears to have more resem- 

 blance to that of Peltogaster. As Darwin says of certain males (vol ii. 

 p. 23), that they merely represent " bags of spermatozoa/' it may be said 

 of the perfectly developed Peltogasters that they are only bags of eggs. 



(To be continued.] 



