MELICERTADjE. 91 



surface, down to the C-oaca. The vibratile tags can be easily seen. There is a con- 

 spicuous nervous ganglion on the dorsal side, just above the neck, and below the two 

 eyes. These latter are beautiful little hyaline spheres (fig. 37t) resting on patches of 

 crimson pigment. 1 The two antennae rise from the corona, on the sloping walls of the 

 buccal funnel between it and the ventral gap (fig. 3a, a). They are adnate at the base, 

 and each carries a bristle that can be withdrawn within a tubular sheath (fig. 3g), as in 

 Melicerta. The ovary is frequently obscured by a large egg, lying across the body, in which 

 the red eyes, moving cilia, and mastax of the young animal are distinctly visible. I have 

 frequently noticed living spermatozoa attached to the outside of the ovary : how they can 

 get there it is not easy to see, unless they can find then - way from the cloaca, up the 

 lateral canals, and out of the vibratile tags into the body-cavity. 



I have watched the formation of an ephippial egg from the first enclosing of a con- 

 siderable portion of the ovary, through the changes shown in figs. 3k, 81, 3m, to the 

 ultimate production of an egg (fig. 3w), covered with a deep layer of hexagonal cells, 

 and bristling with spines, from each spot where the angles of the hexagons meet. As 

 Mr. Davis has well observed, it is a misnomer to call these " winter " eggs, for they occur 

 in all seasons of the year. 



The male (PL VIII. 30* and 8p), as usual, consists of little else than a sperm-sac and 

 penis. Its general appearance when swimming is shown by Mr. Davis (he. cit.) and its 

 internal structure has been worked out by Dr. Colm, one of whose figures is reproduced 

 in PL D. fig. 10. Dr. Cohn (he. cit.) says that the nutritive system, from mouth to 

 cloaca, is wholly wanting ; that the vascular system is indistinct, though probably pre- 

 sent ; that the whole head is occupied by a great nervous ganglion ; and that there are 

 two eyes, which consist of refracting lenses set in pigment. He also describes, and 

 figures, the spermatozoa (PL VIII. fig. 3q), which he saw under unusually favourable 

 circumstances ; and noticed their attachment to the outside of an ovum (fig. 8r). 2 



Length. Diameter of large cluster, about ^ inch ; length of individual, about ^ (T inch. 

 Mr. Gosse has counted as many as 70, and Mr. Davis 100, in a single cluster. Habitat. 

 Lakes, clear ponds, and pools : common. 



0. dossuaeius, Hudson, sp. nov. 



(PL VIII. fig. 4.) 



Cuphalots i phon dossuarias . . Hudson, J. Roy. Micr. Soc. 2 Ser. vol. v. 1885, p. Gil, pi. xii. fig. 4. 



SP. CH. Cluster iinsymmctrical, of one adult and a few of its young ; tubes dis- 

 tinct ; ventral antennas behw the corona, hng, adnate for nearly their tvhole length. 



This rare species was discovered by Mr. Bolton in September 1884 near Birmingham. 

 It is remarkable for the size, shape, and position of the antennae, which stand on the arched 

 ventral surface like a rifle-sight on the barrel. The specimens that Mr. Bolton sent me 

 were all solitary, carrying with them, as they swam, their cases with the contained eggs ; 

 but Mr. Bolton tells me that the clusters which he usually met with consisted of one 

 adult and a few young individuals of various sizes. On one occasion, too, he saw an 

 adult with one large egg, and four much smaller eggs in its tube. If these latter were 

 male eggs, and the former a female one, this observation would, I believe, be unique. 



I had no opportunity of studying the internal structure of this Botiferon closely ; 

 but I detected no difference in this respect between this species and G. volvox. 



Length. My solitary specimen was ^ inch. Habitat. Near Birmingham (T.B.). 



1 Dr. Imhoff says (lot. cit.) that in the specimens in Lake Zng the pigment is black, and Dr. v. 

 Eichwald (loc. cit.) found specimens, in ditch-water at Hapsal, in which the eyes were invisible. 



- The Rev. Lord S. G. Osborne has described (in a letter to the 'English Mechanic,' March 1, 1878), 

 clusters of Conochilus volvox which bear at their centres bundles of fine stick-like diatoms. I am 

 indebted to his Lordship for a cluster, mounted by himself, and containing these needle-shaped bodies. 

 They appear to be of three kinds ; they are colourless, and their distinctive markings (if any) are so 

 obscured by the rotiferous jelly, that it is very difficult to say whether they are diatoms or desmids. 

 Lord Osborne's explanation of their presence in the cluster is no doubt the true one : namely, that 

 they are drawn in point-downwards, bit-by -bit, at each sharp contraction of Conochilus into its ball. 



