MELICEETADiE. 75 



(fig. le) ; and below it, at right-angles to it, are two thin walls (fig. la) looking like 

 the supports of a bracket, the chin being the bracket itself. These supports form, 

 with the chin above, and the ventral surface between them, a cup or recess somewhat 

 like the cup of M. ringens. I could not, however, detect any cilia in it. Below the cup is 

 a large viscous knob, as in the other species, but differing from them in bearing on its 

 upper surface two or more curved bristles (fig. 1/), h) pointing to the cup. 



The tube is not nearly so compact as that of M. ringens, or even of Limnias 

 ceratophylU. It is composed of large ovoid focal pellets, which are laid upon one 

 another somewhat obliquely in rings, as shown in fig. 2d. 



The pellet is formed in the intestine (figs, lb, le, i), and when it is ready the animal 

 bends down over the cloaca (el), the rectum (r) is everted and pushed forward, and the 

 pellet is shot over the shoulder so that it rubs against the viscous knob and is thus held, 

 partly by the sticky surface of the knob, partly by the curved bristles already mentioned. 

 When it has thus caught the pellet, the creature, with a swift twist backwards, pushes it 

 on to the top of its tube. The intestine (i) is large and usually contains a fecal pellet 

 in the course of formation. These are not all appropriated to the construction of the 

 tube, but are often suffered to float away. The gastric glands (</</i are conspicuous, 

 and form an arch over the top of the stomach : they contain large nucleated cells. 

 The two ventral antennae (a) are short and are placed rather as they are in an Q^cistes 

 than in a Melicerta. Mr. Hood tells me that he has seen the male, and that it resembles 

 that which I have figured as the male of M. tubicolaria. He further notices that the 

 young female acquires its perfect form in four days after it has been hatched. Although 

 M. Janus has so many points in common with the genus CEcistcs that I originally placed 

 it there, yet as it really has four lobes in its corona (however inconspicuous two of them 

 may be) I have felt constrained to add it to the Melicerta. 



Length, t \ of an inch. Habitat. Lochs only, Forfar, Perth, Ayr (J. II.) : abundant. 



Genus limnias, Schrank. 



GEN. CIL Corona distinctly of two lobes ; dorsal gap wide ; dorsal antenna 'minute ; 

 ventral antennae obvious ; tube without pellets. 



The genus Limnias differs from Melicerta in the shape of its lobes, and the structure 

 of its tube. The corona is much broader than it is high, and consists of two nearly 

 circular lobes connected on the ventral side by a hollow opposite to the buccal funnel, 

 and separated on the dorsal side by a gap. The double ciliary wreath, buccal funnel, 

 and chin are similar to those of Melicerta. There is no ciliated cup, though there is a 

 hollow beneath the chin somewhat like one. 



The tube is unlike that of Melicerta or CEcistes ; it is really tubular in form, widen- 

 ing a little towards the top ; it is often opaque, and is not composed of pellets ; those 

 of the different species are unlike each other. 



The internal structure of the common species, L. ceratophylU, is almost precisely 

 that of Melicerta : it is said by Ehrenberg, and often repeated, that it has no vascular 

 system, but this is a mistake. I have seen, but have not had an opportunity of study- 

 ing, the rare species L. annulatus ; neither have I been able to find any account of its 

 internal structure. 



L. cERATor-HYLLi, Schrank. 

 (PL VI. fig. 1.) 



Limnias ceratophylU . . . Ehrenberg, Die Infus. 1838, p. 402, Taf. xlvi. fig. 4. 



,, ,, ... Gosse, Evenings at the Microscope, 1859, p. 302, with fig. 



,, „ ... Pritchard, Infusoria, 1861, pi. xxxii. figs. 388-392, 



pi. xxxvi. fig. 2. 

 Melicerta ceratophylU . . . Gosse, Popular Sci. Rev. vol. i. 1862, p. 481, pi. xxvi. fig. c. 

 Limnias ceratophylU . . . Moxon, Trans. Linn. Soc. vol. xxiv. 1864, p. 458, 



pi. xlvii. n 3. 



