42 ANIMAL PARASITES AND MESSMATES. 



Cyclatella annelidicola, because of its residence in a Clyme- 

 nian annelid. Claparede and Keferstein have observed a 

 species, the Loxosoma singulare, on a capitejlian annelid, 

 of the genus Notomastus, at St. Vaast-la-Hogue, on the 

 coast of Normandy. After this, Claparede found another 

 species, the Loxosoma Kefersteinii, in the bay of Naples, 

 on an Acamarchis, a bryozoarian mollusc. Mons. 

 Kowalewsky has observed in the Bay of Naples the 

 Loxosoma Napolitanum. 



We found some years ago the Pedieellinse in so 

 great abundance in the oyster beds of Ostend, that the 

 baskets and other things floating on the water were lite- 

 rally covered with them. "We have several times since 

 endeavoured to procure them again, but it was in vain 

 to search in the same places where they were formerly so 

 abundant : we have not been able to discover a single one. 



The class of worms includes not only parasites, it 

 contains also, as we shall see, true messmates ; we find 

 some on crustaceans, on molluscs, on animals of their 

 own class, on Echinoderms, and on Polyps. 



One of the most curious of these worms is the 

 Myzostoma, whose true nature has just been revealed by 

 the excellent researches of Mons. Mecznikow. These 

 myzostomes resemble trematode worms, but they have 

 symmetrical appendages, and are covered with vibratory 

 cilise. They live on the cdmatulae, and run upon these 

 echinoderms with remarkable rapidity. They have not 

 hitherto been found elsewhere; they are evidently no 

 more parasites than the last mentioned, and their place 

 ■is among free messmates. Two great annelids are 

 found, the one, the Nereis bilineata, by the side of Paguri 

 in the same shell, the other, the Nereis succinea, accord- 



