440) MR. F. £. BEDDARD ON THE [ Nov. 5, 
far as these points are concerned, it seems clear that in Macropusmajor 
the semen passes inwards by the lateral canals, even when the opening 
into the median canal exists, and in Osphranter erubescens that the 
embryo passes out by the median canal; but in view of the differ- 
ences of structure and relations of the different parts that have been 
observed in different genera and species, it is not yet safe to siy that 
these statements constitute a rule for the whole of the Macropodide. 
5. Contributions to the Natural History of an Annelid of the 
Genus Dero. By Frank E. Bepparp, M.A., F.Z.S. 
[Received September 25, 1889.] 
I have had the opportunity lately of observing the sexual form of 
a species of Dero, which [ identify with D. perrieri. A large 
number of these Annelids made their appearance in some water 
containing Chara which I received from Messrs. Bolton of Birming- 
ham; at the end of August all, or nearly all, were sexually mature. 
As there appears to be no account of the reproductive organs of this 
worm extant, I think it worth while to publish the present notes. 
Except as regards the sexual organs, they are for the most part 
confirmatory of Perrier. 
The worms reached a length of about half an inch; they were 
extremely active in their habits, wriggling about very much after 
the fashion of a free-living Nematode; the colour appeared to the 
naked eye of a dark violet posteriorly ; in front the development of 
the clitellum and of the sexual products produced an opaque yellowish- 
white appearance. The eggs could be distinctly seen and counted 
with an ordinary hand-lens ; they lie behind the clitellum; I 
observed the number to be almost constantly three. I have made 
no observations upon the tube, which, according to Perrier (“ Histoire 
naturelle du Dero obtusa,” Arch. Zool. éxp. t. i. (1872) p. 65) and 
Bousfield (‘‘ The Natural History of the Genus Dero,” Journ. Linn. 
Soe. vol. xx. (1887) p. 91) are fabricated by the worms. The fact 
that they make for themselves an habitation of this kind distinguishes 
the genus Dero from Nais, to which all recent writers concur in 
regarding Dero as closely related. 
The new facts which are brought forward in the present communi- 
cation strongly support that view of the affinities of the worm, which 
may indeed now be regarded as fully established. 
The general anatomy of the worm has been described chiefly 
by d’Udekem (‘‘ Nouvelle Classification des Annélides sctigéres 
abranches,” Bull. Acad. Roy. Belge, t. xxii. pt. 2, p. 549 et seq.), 
Perrier (loc. cit.), and Bousfield (doc. crt). Stole (‘* Dero digitata, 
O. F. Miiller, Anatomicka a histologicka studie,” SB. béhm. Gesells. 
1885, p. 65), in a paper overlooked by Bousfield and omitted from 
an otherwise tolerably complete list of papers dealing with Dero, 
has contributed details of importance, being apparently the first to 
have made use of the section method. I refrain from attempting 
