52 W. Lilljeborg on the Genera Liriope and Peltogaster. 



but Clistosaccus differs from both in the absence of a buccal ori- 

 fice. It appears therefore to have remained at a lower stage of 

 development, although, as compared with Peltogaster, in its in- 

 ternal structure it represents a higher degree, and approaches 

 more to Sacculina. 



The portion of the Clistosaccus which had traversed the skin 

 of the Pagurus (fig. 6 a) was enveloped by a thick, but not com- 

 pact, muscular and cellular membrane, which appeared to be a 

 continuation of the second membrane of the pallium. Imme- 

 diately under the skin of the Pagurus the penetrant portion of 

 the parasite bore a circle of soft ramose appendages (figs. 6 b 

 & 7), consisting of a delicate and transparent external mem- 

 brane, and, within this, of granules and small round vesicles 

 without distinct nuclei. Beneath these the integument became 

 thicker; so that the thickest part was near the base, where it 

 presented a very uneven surface. 



In the structure of this part we find a striking analogy with 

 Anelasma squalicola. The peduncle of the latter, which pene- 

 trates the skin of the Shark, has a great resemblance to the por- 

 tion of the Clistosaccus which traverses the skin of the Pagurus. 

 It is also furnished with similar ramose appendages. As Clisto- 

 saccus has no buccal orifice, it must be supposed to obtain its 

 nourishment by absorption; and the ramose appendages are 

 probably absorbent organs, comparable to the villosities of the 

 intestines in the higher animals. These appendages in Ane- 

 lasma may perhaps have a similar function. 



When the pallium is opened (fig. 6), the animal presents a 

 structure almost exactly in accordance with that of Sacculina. 

 There is a muscular, oval, whitish internal body (c), surrounded 

 on all sides by oviferous tubes. This body has' a small neck, by 

 which it is fixed to the basal part of the animal. The body is 

 comparatively smaller than in Sacculina, and the author could 

 not ascertain whether it is attached to the pallium. Within the 

 body there were more or less developed ovules, but not enclosed 

 in ramified tubes. As the pallium is completely closed, a fissure 

 must be produced in it somewhere for the escape of the young. 

 The author gives the following characters of his new genus and 

 species : — 



Clistosaccus, nov. gen. 



Animal e Crustaceorum classe et Cirripediorum subclasse, generibus 

 Sacculince et Peltogasteris affine, ectoparasiticum, in abdomine Pa- 

 guri degens. 



Animal sacciforme, saccum rotundum vel ovalem, clausum et Isevem 

 praeberis, latere uno (inferiore) in abdomine Paguri immerse, molli 

 et appendicibus ramosis (absorbentibus ?) prsedito, ibique pallii tunica 

 extima chitinosa cum cute Pagvri coalita. Pallio aperto corpus 



