MELICEBTAD2E'. 79 



The gradual changes of form in the young are shown in figs. 3, x, y, .:, which 

 arc all taken from the same individual in different stages of growth. Fig. :!. x, shows 

 it when only ._,;',„ inch long, and with a sort of hump where the dorsal antenna, is to be. 

 Twenty-four hours after, the hump had become a short antenna (fig. 3, y) ; in four days 

 the young animal had grown to ^ inch, in six days to Q ? s inch, and in twelve to -'. inch, 

 by which time, as shown in fig. 3, z, the characteristic antenna was well developed : at 

 this stage of its growth I unfortunately lost it. 



I have little doubt, that M. du Trochet was the first discoverer of C. Limnias. In 

 the " Annales du Museum d'Histoire Naturelle," t. xix. 1812, p. 385, pi. IS, figs. 19 to 21, 

 he describes and figures a tube-maker, Rotifer cruciger, with a fawn-coloured tube and 

 a long dorsal antenna, and he noticed that the animal explores with it in all directions. 

 It is true that he figures two eyes, " saillants et globulaires," near the summit of the 

 dorsal antenna, one on each side of it ; but these (if the animal were C. Limnias) must 

 have been something extraneous, accidentally attached to the antenna ; possibly two air- 

 bubbles. 



Length. About 4 ', r inch. Habitat. Neighbourhood of London (Mr. Slack); Sand- 

 hurst, Berks (Dr. Collins); Woolston, near Southampton (P. H. CI.); Cheltenham 

 (Miss Saunders i ; Lochs, Forfar (J. H.) ; Nailsea, near Bristol (C. T. Il.i : very partially 

 distributed. 



C. candidus, Hudson, sp. nov. 



SP. CH. Dorsal antenna very long ; tube irregular, semitransparent, gelatinous. 



Mr. J. Hood found this very rare Rotiferon in Loch Lmidie in October 1880, and again 

 between September and December in the same loch next year. He found a few speci- 

 mens in his aquarium, but evidently from eggs on weeds brought from the same spot. 



Mr. Hood points out that it differs from C. Limnias not only in its tube, but also in 

 its stout wrinkled foot, which is kept habitually in this condition. I have always noticed 

 that the foot of 0. Limnias (when in its tube) is delicate, tapering, and smooth ; but Mr. 

 Gosse found that, on his dislodging one from its tube, the foot became of nearly equal 

 thickness throughout (as in C. candidus), and of about one-third the diameter of the 

 body, from which it was abruptly separated. The whole length, too, was then studded 

 with wrinkles, which at intervals took the form of great thickened rings. The foot termin- 

 ated in a circular sucking disk. The two species are very much alike ; but their tubes 

 differ so much that I have thought it best to keep them apart. 



Length, _/„ inch. Habitat. Loch Lundie (J.H.) : very rare. 



Genus CECISTES, Ehrenberg. 



GEN. CH. Corona a wide oval, indistinctly two-lobed ; dorsal gap minute; 

 dorsal antenna absent ' ; ventral antennae obvious. 



In this genus the tube is extremely irregular and variable in shape ; it is usually 

 of a loose fluffy texture, and encumbered with extraneous matters of all kinds. In one 

 species, however, it is compact, like that of Limnias ceratopliylli ; in another it is 

 formed of faecal pellets ; and in a third it resembles that of Melicerta tubicolaria. 



The corona is no longer distinctly lobed, and becomes nearly circular ; it is hollowed 

 a little on the ventral side opposite to the buccal funnel. The ciliary wreath is double, 

 and is on precisely the same plan as that of the preceding genera ; only the dorsal gap 

 in it, though distinct, is so minute as easily to escape notice, unless the animal be in a 

 favourable position. Ehrenberg failed to see either it or the secondary wreath ; and, 



1 Probably a minute setigerous pimple, which has escaped observation. 



