MELICERTAD.E. S'J 



Genus CONOCHILUS, Ehrenberg. 



GEN. CH. Cluster frec-swivwwig, of several individuals, inhabiting coherent gela- 

 tinous tubes ; corona horsc-shoe-shaped, tmnsverse ; gap in the ciliary wreath ventral ; 

 buccal orifice on the corona, and towards its dorsal side ; dorsal antennae absent ; ' 

 ventral antennae obvious. 



Take a clay model of an (Ecistes, and cut off tbe head by a transverse section through 

 the neck. Lift up the head, and reverse its position, placing the surface of tlie corona on 

 the decapitated trunk, so that the entrance to the buccal funnel may point towards the 

 centre of the dorsal surface. Tliere will tluis be obtained a rough representation of the 

 relative positions of the trunk, corona, and ciliary wreaths in Conochilus. Such a 

 violent alteration in the general plan of the MelicertadcB might almost seem to entitle 

 Conochilus to a family by itself, but its affinities are so clearly with this group that it 

 may well remain here. 



On the surface of the corona,' close within its edge, and parallel to it, rmis a groove, 

 which is broadest and deepest opposite to the dorsal surface, where it is confluent with 

 the entrance to the buccal funnel. The groove grows both narrower and shallower on 

 each side as it approaches the ventral surface, and ceases just before reaching a ventral 

 gap in the corona. 



The buccal funnel, except at its wide entrance, is covered by a sloping roof, formed 

 of the uplifted corona, which here rises mto a kind of pent-house, notched at its apex. 

 The principal wreath runs round the outer edge of the groove, and is joined, at each side 

 of the ventral gap, by the secondary wreath. This latter fringes the groove's inner 

 edge ; and on reaching the buccal fmmel, bends sharply back, rising up each edge of its 

 walls, till it has reached the notch described above ; so that m Conochilus, as in other 

 MelicertadcB, the entrance to the buccal orifice Ues between the two wreaths, and is bor- 

 dered by the secondary one. 



The two known species differ considerably in their modes of clustering, and in their 

 antenna2 : they apparently closely resemble each other in other points, but only one 

 has been really studied, viz. C volvox.^ 



C. VOLVOX, Ehrenberg. 

 (PI. VIII. fig. 3.) 



Conochilus volvox .... Ehrenberg, Die Infiis. 1838, p. 393, Taf. xliii. fig. 8. 



Eichwald, Dritt. Nacht. z. Infus. Busslands, 1852, p. 520. 

 Cohn, Sicb. u. Kull. Zeits. Bd. xii. 1863, p. 197, with figs. 

 Pritchard, Infusoria, 1861, p. 661, pi. xxv. 365-370. 

 Gosse, Po^mlar Set. iJeu. vol. i. 1862, p. 491, pi. xxvi. figs.c,/. 

 Davis, Mon. Micr. J. vol. xvi. 1876, p. 1, pi. cxliii. 

 Bedwell, J. Roy. Micr. Soc. vol. i. 1878, p. 176, pi. xi. 

 Hudson, /. Eoy. Micr. Soc. vol. ii. 1879, p. 3, pi. ii. 

 Imhof, Zool. Am. No. 147, 1883. 



' Possibly very minute. 



= Elirenberg misunderstood the corona of C. volvox, and described it as surrounded with a single 

 wreath of cilia and bearing four papillse on its surface. He placed the buccal orifice on the ventral 

 side, where the ventral gap is ; and suggested that the four papillne might be a sort of upper lip to the 

 mouth, the edge of the disk itself being the lower one. Dr. Cohn, in his otherwise admirable paper 

 (loc. cit.), draws the buccal orifice on the ventral side, and wTongly places the antennro between it and 

 the dorsal surface. His conical protuberance over the antennie is also singularly out of shape and 

 proportion. The corona and antenna; were first correctly described by Mr. Davis (loc. cit.), whose 

 observations I have repeatedly verified. 



' SlroplwsplKcra ismailovicnsis (Poggenpohl, N. MHn. Mosc. t. x. 1876) is, I think, a Conochilus ; 

 with two short separate antennte lying between a pair of ventral hooks. 



Mcgalotrocha volvox 

 Conochilus volvox . 



