MELICERTAD/E. 73 



Tubicolaria. Naias .... Pritcharcl, Infusoria, 1861, p. fif>8, pi. xxxii. figs. 379-382. 



Melicerta tyro Hudson, Mon. Micr. J. vol. xiv. 1875, p. 225, pi. cxix. 



Tubicolaria Naias . . . . Fullagar, J. Quekett Micr. Club, vol. iv. pp. 182, 202, 



pis. xvi.-xviii. 



Lobes, when expanded, more than three times the width of the body ; antennae very 

 long ; tube a gelatinous sheath without pellets. 



Three striking peculiarities at once catch the eye in this beautiful Melicerta, viz. 

 (1) the great size of the trochal disk ; (2) the wonderful length, backward setting, 

 swollen bases, and great flexibility of the ventral antennae ; and (3) its semi-trans- 

 pareiit tube, which, though resembling that of the Floscules, has yet a character of its 

 own. 



The tube, unlike those of all the other species, bears no pellets at any time. It is 

 of a loose fluffy texture, and extends from the surface almost up to the Rotiferon itself. 

 There is a central hollow, little wider than the creature's body, up and down which the 

 animal moves. Horizontal layers of diatoms, and other foreign bodies, cross the tube at 

 irregular intervals, and mark the height at which the tube then was, when they were 

 entangled. 



The corona is very large. It is more than three times the width of the body ; thus 

 considerably exceeding the proportions of M. ringens and M. conifera. Its four lobes 

 are really all curved, just like those of M. ringens, and are often seen fully expanded 

 and round ; but the animal has a habit of bending the corners of the two upper lobes, 

 so as to give the whole disk a butterfly shape. 



There is a ciliated cup under the chin, just as in the two former species, but no 

 pellets are formed in it. I examined it carefully several times, but I could find no 

 lines of cilia between the chin and cup, such as Mr. Gosse observed in M. ringens ; 

 neither could I see the minute notches in the chin, through which, in that species, 

 minute atoms slip from the buccal funnel, to be conducted by lines of fine cilia to the 

 pellet cup. 



The muscular, nutritive, secreting, and reproductive systems, are so similar to those 

 of M. ringens as to call for no further remark. 



Vascular System. Leydig notices the absence of the contractile vesicle, and says 

 that he traced the two lateral canals from the corona, where they originate in two coils, 

 across the body, from the dorsal to the ventral surface, and so down to the cloaca. He 

 says that, after repeated efforts, he at last saw the two vibratile tags in the corona. 

 I was more fortunate, for I made out five vibratile tags on each side of the body, though 

 I could not see exactly where the lateral canals ended. I could find no contractile 

 vesicle, but on two occasions I noticed that the empty intestine became distended and 

 very transparent, and then shot out its fluid contents through the cloaca. While this 

 was going on, the passage from the stomach to the intestine was closed. It would thus 

 appear as if the intestine itself was filled by the lateral canals, and discharged the office 

 of the contractile vesicle. It will be seen subsequently that something similar takes 

 place in other Rotifera. 



Organs of Sense. I have failed to discover any eyes in the adult, but they are very 

 conspicuous in the young animal (PL V. fig. 2b). The antennae are of great length, 

 twice as long in proportion as those of M. ringens ; and, as they are transparent, it is 

 easy to see how the muscle that runs up the centre to the setigcrous knob at the top 

 can withdraw the knob, thus infolding the tube, till the knob comes right down to the 

 base of the antenna. When the animal is contracted into its tube, the antenme are closely 

 pressed to its club-shaped body ; and, as it rises, they, too, slowly rise from their 

 recumbent position, while the perivisceral fluid, under the pressure of the transverse 

 muscles, drives the knobs up the antenna?, and so completely extends them. 



The Male. I believe that the male Rotiferon drawn in PL V. fig. 8c, is the male of 

 M. tubicolaria. I had a small piece of Anacharis with about a score of females attached 

 to it, and while observing them I saw this young male circling round one of them. It 



