NOTES ON SOME AQUATIC OLIGOCHATA. 197 
and 16. It is conical in its general outline, with a circular 
groove near the tip, giving it a pointed appearance. 
The male pores (spermiducal pores) are, as is always the 
case in the Tubificide, in Somite xz slightly dorsal of the 
ventral chetz. 
The spermathecal pores are in a similar position in 
Somite x. In both cases the cuticle dips inwards at the pore, 
and is folded around its lip. 
The vascular system is of the usual Tubificid! type. 
There is a pair of lateral dilated hearts in Somite vi1r. These 
contract not together, but alternately. In the genital segments 
these vessels are contractile, and lie on the sperm- and ovi-sacs ; 
in other segments a pair of narrow convoluted vessels lie 
immediately below the body-wall. 
The most important system of organs after the chetz are, 
of course, the genitals. These are shown in situ in fig. 17, 
which is taken from a careful sketch made from the living 
worm, sufficiently compressed to prevent movement, and to 
allow the organs to be seen without undue distortion or dis- 
placement. The clitellum covers the dorsal surface of x1, x11, 
and part of x as far as the cheetee, sometimes even part of x11I. 
The Male Organs.—A pair of testes in the 10th segment 
are attached to the anterior septum of this segment. 
The funnels of the sperm-ducts lie against the posterior 
septum of the 10th segment; from the funnel on each side the 
narrow ciliated duct passes, with only slight undulations, back 
through the Segment x1 and intoSegment x1. Here it enters 
the glandular “ atrium ;” this narrows, loses its glandular 
coat, passes forwards into Segment x1, and here opens to 
the exterior. 
The “ cement gland,” or prostate, lies in Somite x11, and 
here opens into the atrium. 
1 In a recent paper (“Monog. Geskych Tubificidi”) Stole gives some 
excellent figures of the arrangement of vessels in several genera, and repre- 
sents several new points; e.g. the lateral hearts in his two new genera 
Lophocheta and Botbrioneuron arise, not from the dorsal, but from a 
supra-intestiual trunk. 
