1015.] J. STEPHENSON : Indian Oligochaeta. 43 
ON THE SPERM-SACS IN THE GENUS ENCHYTRAEUS. 
In a recent paper (23) I wrote of the sperm-sacs in this genus, ‘‘ The sacs do not 
include the funnels of the vasa deferentia’’; and since they are, in the stages at which 
I have examined them, completely closed, it is not obvious how the spermatozoa 
escape. A specimen of Enchytraeus barkudensis perhaps explains this (v. inf.); the 
wall of the sac was apparently wanting in part,—hence it would seem that at a cer- 
tain stage the sperm-sac disintegrates or ruptures, possibly under pressure from with- 
in. Indeed, unless we assume an active penetration of the sac wall by the ripe sper- 
matozoa there would seem to be no other means of exit. I do not, however, think we 
are at present entitled to exclude the active penetration of the sac; a re-examina- 
tion of my specimens of E. harurami has also shown, in one case at least, a small 
break in continuity of the wall of a sac;— but on the one hand it is possible that 
slight damage of the kind might occur during section-cutting, and on the other the 
appearances do, in one or two places, suggest the penetration of the sac-wall by 
mature spermatozoa. 
_ The question now arises —Are sperm-sacs present throughout the genus Enchy- 
traeus? In the published descriptions of a number of species they are said to be 
present', in others they are not mentioned, while in some they are definitely said to 
be absent (as in E. indicus, IQ, and compare 22,p. 322). In the latter class I am sure 
(as regards the specimens I myself examined) I may place E. dubius and E.nodosus, 
described some time ago by me from the Clyde (17). But is.it possible that after 
rupturing, the wall of the sperm-sac entirely disintegrates, so that in the later stages 
not even the remains of sacs are visible? On this supposition the species in which the 
sacs are absent or are not noted may have been described from specimens in a late 
stage of maturity; it may be noted that I have never seen a clitellum in E. barkuden- 
sis, and in E. harurami, which also possesses testis-sacs, the clitellum, though distin- 
guishable, was not conspicuous. It is, however, scarcely possible that the specimens 
of E. dubius, without testis-sacs, belonged to a late stage (c/. text-fig. 2 and fig. 12, 
pl. ii of the original description, both showing large testes,—hence an early rather 
than a late stage). 
It may perhaps be necessary ultimately to remove E. dubius from the genus (I 
included it, as the name implies, somewhat doubtfully); or the present genus may have 
to be split up into two, one comprising those species which have and the other those 
which have not sperm-sacs. But a number of already described forms may have to 
be re-investigated before this can be done. 
I may refer briefly to the condition in E. carcinophilus recently described by Baylis 
(I). The sperm-sacs appear to be of the nature of those described for E. barkudensis, 
etc. ; but the testes are said to be in segment x on septum Io/II, 2.e. outside the 
sperm-sacs,—it would be impossible so to describe them if they were within the sacs. 
l'ais appears to me to be an unlikely position; apart from the analogy of E. harurami 
and E. barkudensis, to mention only forms with which I am myself acquainted, there 
! So recently Stirrup (24), for Enchytraeus albidus. 
