MELICERTAD^. 87 



M. ALBOFLAVICANS., Ehrcnberg. 

 (PI. VIII. fig. 2.) 



Megalotrocha alboflavicans . . Ehrenberg, Die Infus. 1838, p. 397, Taf. xliv. fig. 3. 



,, . Pritchard, Infusoria, 1861, p. 665, pi. xxxii. figs. 374-378. 



. . Gosse, Popular Sci. Rev. vol. i. 1862, p. 491. 



. . Weisse, L'Acad. Imp. St. P&tersb. 1 S6r. t. iv. No. 8, 1862, 



p. 7, with figs. 

 Lacinularia alboflavicans . . Cubitt, Hon. Micr. J. vol. viii. 1872, p. 9, pi. xxiii. fig. 5. 



This is a comparatively rare animal, though it has been known for upwards of a 

 century. Had it been common it would never have been supposed to be a Lacinularia 

 without a tube, for only those who have never seen it could make such a mistake. It 

 differs obviously from L. socialis in its shape and habits, as well as in its being orna- 

 mented with a necklace of four white opaque knobs, " like a row of pearls," stretching 

 from shoulder to shoulder across the ventral surface. These are so placed, that when 

 the animal furls its corona they border the edge of its then pear-shaped body. 



The cluster radiates in all directions from a small space on the stem or leaf of a plant, 

 and often consists of both adults and their young. Now and then a young brood will 

 swarm out, as in Conochilus volvox ; and, when swimming away, circling round each 

 other in search of a resting-place, may easily be mistaken for a young cluster of that 

 species. The ways of the animal are unlike those of L. socialis. It is a much more 

 timid creature, and does not expand so freely. When a cluster is undisturbed, first one 

 and then another will contract with a sudden twist, to expand in leisurely fashion at its 

 own pleasure ; but every now and then a panic seizes the whole cluster, and they all 

 rush together into a contracted mass, with a curious circular sweep, as if some violent 

 eddy had struck them. 



The creature has a peculiar habit of swelling out at times the surface of the corona, 

 so that it is curved up above the ciliary wreath ; but in other respects the two ciliary 

 wreaths, the chin, and the buccal funnel are similar in plan to those of L. socialis ; and 

 so is the whole alimentary tract. The two vesicles, which some take to be salivary 

 glands, and others mere horny stays to the buccal funnel and mastax, are yellowish ; 

 and so are the trophi. The gastric glands are somewhat three-sided in outline when 

 seen ventrally. The lateral canals and their vibratile tags are obvious (figs. 2 to 2c), 

 but the contractile vesicle (if any) has not been seen ; neither has it been determined 

 how the lateral canals end posteriorly. No nervous ganglion or antenna has as yet been 

 seen, and the two red eyes only in the egg and young. 



[Mr. W. G. Cocks, of Dalston, has been very successful in keeping this and other 

 fine Khizota in a tank. He has favoured me with many valuable observations on the 

 habits and development of this species ; and I am indebted to him for a supply of speci- 

 mens. I noticed that, in one case, when an egg was discharged in my sight, it separated 

 and fell down among the crowded feet of the cluster ; while, in another, it hung awhile to 

 the cloaca after exclusion. Presently a young one was swimming free, probably hatched 

 in the trough. It was colourless, very transparent ; and swam smoothly, evenly, and 

 swiftly, by the rotation of the cilia on its expanded corona. Then came shooting-by a 

 slender creature (PI. D. fig. 9a), about ^^- inch long, with truncate, apparently ciliate, 

 front, tapering regularly to the hind extremity. In this, though full of a bright granu- 

 lation, I could not detect any viscera, nor other organs. I conjecture this was the new- 

 born male of the same ; as fig. 9 is probably a new-born female. P.H.G.] 



In Dr. Weisse's figure (loc. cit.) of the female embryo leaving the egg, it will be noticed 

 that the four opaque warts on the trunk, as well as the eyes and mastax, are already 

 formed. 



Length. About -jV inch ; diameter of large cluster, about 1 inch. Habitat. On 

 plants in gently running streams, Weybridge, Surrey (W. G. Cocks); Kent (Cubitt, 

 Badcock) : rare. 



