6 THE ROTIFEEA. 



greenish-yellow, slightly gelatinous balls, on the stems of water plants. The ten or twenty 

 individuals, of eacli group of this social Eotiferon, are all fixed towards the point which 

 attaches the parasite to the plant. No distinct tubes are visible ; but the QScistcs are 

 immersed in a continuous mass similar to the tubes of other species of the genus. 



The animal e.xpands and contracts continually, and with great vivacity. Its great 

 length, and its corona, place it close to Gosse's serpentinus, but it has not the dorsal 

 hooks of this latter. M. Weber describes the corona as a circular single curve of eilia, 

 notched slightly on the dorsal side, and fringing the edge of a deep funnel with a central 

 buccal opening at the bottom of it. If this description be correct, then of course the 

 animal is no CEcistes : nor can it belong to the Melicertadm at all ; for these have all 

 laterally placed mouths, lying behind, and outside of, an imperforate disc, and on this 

 disc are two parallel rows of cilia, the lower of which is continued round the buccal 

 aperture. M. Wober adds ihat there are two obvious salivary glands above the mastax ; 

 gastric glands ; contractile vesicle and lateral canals ; and one short, setigerous, ven- 

 tral antenna. He could not detect the nervous ganglion ; but he says that, though he 

 was prevented by the dark-coloured intestine and by the habitat of socialis from studying 

 its internal structure thoroughly, yet he was satisfied that it had a strong similarity to 

 other species of the same genus. 



The unpaired antenna, which M. Weber describes as being on the ventral surface, 

 is unlike anything in the Melicertada. But so short and wide apart are the paired 

 ventral antennse in OS. crystaUinus, that it is most difficult to get a view of both to- 

 gether ; and it has been frequently asserted in consequence that it has but one. It is 

 probable, therefore, that there are really two antennje on the ventral surface of socialis.' 



Length. Not recorded. Habitat. Near Geneva (Weber). 



(EciSTES MUCICOLA, Kcllicott (181). 



SP. CH. Corona small, only slightly wider than the body, nearly circular ; foot 

 7iarrow, smooth, and, tvhe^i fully extended, twice to thrice the length of the body ; one 

 min.utc homy 'process on the dorsal surface, Just below the corona; ventral antennae 

 a^ul tube apparently absent. 



" This interesting Kotiferon was found in abundance in a quiet pool, exposed to the 

 sun, and in which great quantities of the gelatinous thaUi of Nostochacece and liivu- 

 lariaceee abounded. Little globules of the alga Gloiotricha pisum were attached to the 

 dissected leaves of Myriophyllum, and in nearly all, one or more of the parasites were 

 lodged, and in some, several found shelter. There is no apparent tube ; the foot is 

 usually attached near the centre of the small masses, and the disc pushed out beyond 

 the surface. It is an exceedingly sensitive species, retiring to shelter at the least noise 

 or shock. The body of the animal resembles somewhat that of serpentinus, but instead 

 of two dorsal hooks below the corona there is one corneous tooth [process] not at all 

 hooked ; the foot is not thick when extended, nor wrinkled, but attenuate and smooth ; 

 its manners are not similar to those of serpentinus, as described by Mr. Gosse, and the 

 eggs are of decidedly different shape and colour," being long-ovate and colourless. 

 (Kellicott, loc. cit.y- 



' I have not copied either o( M. Weber's (igures, as I tliink that tliere must be grave mistakes both in 

 the description and ill the drawings. It is most unlikely that the corona should have only one wreath of 

 cilia, and that the usual imperforate disc should be converted into a deep funnel, with the mouth at the 

 bottom of it. 



■' This may possibly be M. Weber's ffi. socialis, as they are alike in corona, foot, absence of tube, 

 and in their parasitic habit. But M. Weber says that socialis has no dorsal hooks, and one ventral 

 antenna; whereas Professor Kellicott could find no ventral antennie, but saw one dorsal horny process. 



