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Show 352 MR. F. E. BEDDARD O N [May 3, called it-evidently by a slip of the pen-" Molosoma lacteum." I have lately examined a single specimen of an Molosoma which I refer to this species. Unfortunately I a m not able to fix its locality with accuracy, as I found it in a bottle containing water and weeds from various sources. Leydig himself was of opinion that the species might turu out on further study to be an immature stage of M. hemprichii, or of some species with coloured oil-drops in the integument; but he quoted, as against this possibility, Ehrenberg's observation that the red colour is visible in embryos still within the egg, and was therefore, on the whole, inclined to regard the worm as an adult form of a species with a colourless integument. I have, however, recently pointed out thatl the supposed cocoons are in all probability merely cysts into which the worms can temporarily withdraw themselves; so that Leydig's opinion as to the possibility of his Molosoma niveum being an immature form is not necessarily rendered untenable by Ehrenberg's observations. Vejdovsky 2 in describing briefly the characters of his new species, Molosoma variegatum, remarked that it was " hbchst wahrscheinlich von Leydig beobachtet und als Molosoma niveum beschrieben." In a fuller account3 of M. variegatum Vejdovsky establishes its distinctness from Molosoma niveum ; it agrees, however, with that form in possessing some colourless oil-globules in the epidermis, the rest being green. In Molosoma niveum all the integumental oil-globules are colourless. The most recent remarks upon Leydig's Molosoma niveum known to m e are to be found in Vaillant's account of the Oligochaeta in the ' Suites a Buffon.' In that work Vaillant considers it to be not yet established that the supposed species is not the young form of some other Molosoma. I am therefore paiticularly glad to be able, I think, to definitely settle this question. I had on the same slide and under examination at the same time no less than three species of Molosoma-an experience which is not, I imagine, very common. These species were, M. quaternarium, M. niveum, and a species of whose identity I am not quite certain; it was as large as m y Molosoma headleyi4, but may be Molosoma variegatum; I lost sight of it before I completed the examination. The worm which I believe to be Molosoma niveum is at any rate a perfectly distinct species from any known to me. It comes nearest to Molosoma niveum as described by Leydig. Nevertheless, it does not altogether agree with his description. It may therefore conceivably be a new form. It was fully as large as M. quaternarium, and there are other reasons for believing that it cannot be the young of that, or indeed of any other known species. 1 " Note upon the Encystment of Molosoma," Ann. Mag. Nat. Hist., Jan. 1892. 2 System und Morpb. d. Oligochaeten : Prag, 1884, p. 113 footnote. 3 "Molosoma variegatum, Vejd., Prispevek ku poznani nejnizsich Annulatuv," SB. bohm. Ges. 1885. 4 "Observations upon an Annelid of the Genus Molosoma," P. Z. S. 1886, p. 213. |