M. E. Claparede on the Egg of the Nematoidea. 175 and separately examined, proved absolutely free from the cor-puscles that I had found in all the Anemones, with this doubtful exception : I found in one drop a single solitary corpuscle. But the presence of that one might safely be attributed to the fact, that I had previously returned one of the wounded animals to the vessel in question, and from this individual it had probably escaped. Mr. Lewes suggests that possibly his predecessors in research had mistaken for blood-elements "the yellow spherical cells (?) which fill the tentacles of the adult Daisy, and make solid the tentacles of the Anthea.^^ Of the function of these yellow spheres he confesses himself ignorant. The supposition is un-tenable. These spherules are pigment-cells, and they do not fill, far less make solid, the tentacles, but merely line their interior. These pigment-cells occurred in several of the experiments re-corded above, and especially in the fluid obtained by incising the body of Sagartia bellis ; but there is no possibility of confound-ing these with the morphotic corpuscles of the chylaqueous fluid : they diff'er notably in size, colour and structure. The corpuscles (in Anthea) average '0002 inch in diameter; the pigment-cells are fully double this size : the corpuscles have a very faint yel-low tinge, seemingly disks rather than spheres, with no definite walls, and composed of granulose substance ; the pigment-cells are of a full but translucent golden-brown hue, very regularly globular in form, evidently spheres, and with a distinct wall. It is not with any feeling of disrespect to either of the gen-tlemen named, that I forward these results for publication in the ' Annals.' The subject in question is one of considerable physiological importance ; and as diametrically opposite conclu-sions have been arrived at by independent observers, and as it must be settled by the weight of testimony, I have thought it well to add my mite of evidence in favour of the affirmative side. I am. Gentlemen, Yours faithfully, P. H. GossE. XIX. — On the Formation of the Egg and Fertilization in the Nematoidea. By Edouard Claparede*. The dispute between Nelson, Bischoff* and Meissner with regard to the formation and fertilization of the eggs in Ascaris mystax, has not yet attained any satisfactory solution. Not one of these three observers has retracted anything of his previous statements, * Translated from Siebold and Kollikev's Zeitschrift fiir wissenschaftliche Zoologie, vol. ix. p. 106, by W. S. Dallas, F.L.S.
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