Earthworms of the Vienna Museum. io 
The atria are two pairs lying in segments xvii. and xix. 
respectively ; the anterior pair are much the larger ; both are 
coiled tubular glands and both are furnished with penial sete. 
The anterior larger atria are furnished with five of these sete, 
the posterior smaller pair have only two. This was only the 
case, however, on one side of the body ; on the right side there 
were only two to each atrium. They are curved in form and 
show a transverse striation such as is usually found in large 
sete up to nearly the free tip. The free extremity of the 
sete: is not ornamented in any way. 
There are apparently two pairs of spermathece. In 
describing the external characters [ have referred to the 
external aperture of the second pair, which are considerably 
the larger. Supposing that during copulation the worms lie 
in opposite directions, as is the case with Lumbricus, the 
larger pair of spermathecee would correspond to the larger 
pair of atria. Whether the difference in size is a question. of 
maturity or indicates a commencing disappearance of one 
pair of atria and of the spermathece corresponding to them 
I am unable to conjecture. The larger spermatheca showed 
a protuberance on the inner side near ‘to its external aperture ; 
this I suppose to be a diverticulum. Behind the second pair 
of spermathece is a pair of oval glands of the same appear- 
ance but smaller than the spermatheca. Between the two 
glands was a sac containing one or two copulatory sete ; these 
are smaller than the penial sete and of a somewhat different 
form, but resemble them in being unornamented at the tip. 
Behind this pair of glands is another pair apparently also 
furnished with penial sete; but I am not certain as to this 
point or as to whether they lie in the same segment or in the 
next. Structures similar to these have been described in 
other species of Acanthodrilus—for instance in A. Layardi*. 
There are now four or five aguatic Acanthodrilids known. 
EXPLANATION OF PLATE VII. 
Fig. 1. Posterior extremity of Anteus heterostichon, to show the diver- 
gence of the setee. «, ventral, s’, dorsal cease n, nephridiopores ; 
a, anus. 
Fig. 2. Genital segments of Geoscolex maximus. D.V., dorsal blood- 
vessel ; H, “ heart” connecting dorsal with ventral blood-vessel ; 
As, cesophagus ; Ca, calciferous gland; V.S., sperm-sac bent 
upon itself; V.d., vas deferens : At., atrium. ‘The organs of the 
left side only are shown. 
* F. EF. Beddard, “ Note on the Structure of a large Species of Harth- 
worm from New Caledonia,” P. Z. 8. 1886, p. 173. 
