Studies on Earthworms. - Journal of Cell Science

262 WILLIAM BLAXLAND BBNHAM.
drilus the pores of the sperm ducts are in pits, the edges of
which are produced backwards as a ridge, on each side of
somite xx.
There are four male pores in Moniligaster, one pair between
somites vn and VIII, and one pair between somites x and
xi; similarly inAcanthodrilus one pair is on somite SVIII,
and one pair on somite xx. From the sides of each of the latter
the bunches of penial setae project.
The Female Organs.—These consist of the ovaries,
oviducts, and spermathecse.
The ovaries are usually of small size and are frequently
overlooked; for instance, in Titanus brasiliensis Perrier
could find none, but he mentions a pair in somite XVIII in T.
forguesii (29, p. 235).
The ovaries are a single pair; they are always placed behind
the seminal reservoirs, but in Plutellus a pair of
grape-like organs, supposed to be the ovaries, are situated in
somite x, in front of the male organs.
In shape they are pyriform in Lumbricus (xin), grape-like
in Plutellus (x), Pontodrilus (xin), Perionyx (xin),
[Microchseta (XIII)], tongue-shaped in Moniligaster (xn
to xv), though it is doubtful whether these exceptionally large
organs in the last genus are ovaries.
In Perichseta they are flat, pedunculated structures situated
in somite xin.
In Acanthodrilus it is doubtful whether the lobed organ
described by Perrier in somite ix is an ovary or not; but
Beddard has described (40) the ovary of Ac. cap en sis in
somite xnt.
In Eudrilus the ovary, according to Perrier, is very exceptional
; it is a globular sac, which is sessile on a supposed
" spermatheca " in somite xn or xiv. The ovary has not been
found in Anteus, Rhinodrilus, Digaster, nor in Urochseta,
and is very doubtful in Pleurochseta and some of
the above genera.
The oviduct is known in still fewer forms, though its pore
is sometimes noticeable. In Lumbricus it is a short, rather