354 Miscellaneous, 



which constitute this spherule become fewer and fewer ; they seem 

 to separate from each other ; and finally they disappear ; the nucleus 

 is then represented only by its envelope, which looks like an empty 

 shell. While the nucleus is undergoing these transformations the 

 contractile substance gradually disappears, melting away, so to 

 speak, and this in so regular a manner that the general form of the 

 bundle is not altered. The product of this sort of dissolution seems 

 to be a colourless very finely granular substance, enveloping the 

 portion of the contractile mass that has not yet disappeared. In 

 this granular mass we find the muscular nuclei in their place and 

 in all the degrees of degeneration that I have just indicated. 



Thi;s the muscles of the larva are destroyed at the moment when 

 the latter passes to the pupa state, and this in two quite different 

 modes. In the first case the muscvdar nuclei, becoming active, pro- 

 liferate and give origin to a whole swarm of embryonic cells ; and 

 these grow and multiply at the expense of the contractile mass, 

 which seems to disappear before their invasion. In the second case 

 the muscular nuclei seem to degenerate and die, while the contrac- 

 tile substance gradually disappears as by a regular solution. — 

 Comjptes Renclus, February 21, 1881, p. 416. 



On a new Fonn of Segmental Organ in the Trematodes. 

 By M. E. Mac£. 



The authors who have observed the ciliated organs in connexion 

 with the vasculo-excretory apparatus of the Trematod«s (Thirj-, 

 Biitschli, J. Fraipont) have described them in the species that they 

 have studied as little ciliated funnels, often unicellular, each bearing 

 upon a differentiated plate a vibratile fiagellum. In studying a 

 small Distomum from the intestine of Vespertilio muriiius we have 

 ascertained the existence of a very distinct conformation. 



The ciliated organ is single. It is a pretty large cup situated in 

 the median line towards the posterior third of the body, immediately 

 beneath the transverse vitelloduct. Its diameter is nearly half that 

 of the ventral disk, which is situated a little above it. Its orifice, 

 turned towards the ventral surface of the body, is clothed with a 

 row of long vibratile cilia, which, when they are in movement, give 

 it the aspect of one of the ciliated wheels of certain Eotifera. From 

 this ciliated funnel start four vessels. The two superior are directed 

 upwards, and soon elude observation. The two inferior have a 

 transverse direction ; after a short course they open each into the 

 corresponding branch of the great terminal cavity of this apparatus. 



This Distomum has great analogy with D. ascidia of Van Beneden. 

 It difi^ers from it, however, in the place occupied by the vitello- 

 genes. Instead of being in the anterior part of the body, in front 

 of the second disk, they occupy its posterior part. They are two 

 ramified glands in the form of an H, situated below the ovary, 

 against the upper extremity of the two large branches of the excre- 

 tory vesicle; the transverse vitelloduct passes immediately above 

 the ciliated organ in question, and presents a pyriform dilatation in 

 its median part. The intestine is formed by two wide caeca, which 



