NOTES ON ACANTHODRILOID EARTHWORMS, 303 
There are four pairs of lateral sperm-sacs (fig. 19, sps.), 
almost filling the Somites 1x, x, x1, and x11, and hiding the 
cesophagus and the two median sperm-sacs which lie below the 
gut in Somites x, x1, and enclose the testes and ciliated 
rosettes. 
There are two pairs of prostates, in Somites xvi1 and x1x re- 
spectively. Hach prostate (figs. 19 and 26, pro.) is a soft, irre- 
gular body, but roughly cylindrical, terminating in a free, blunt 
point, placed dorsally. The free end is sharply curled upon itself; 
the prostate then gradually widens, and is slightly convoluted as 
it passes downwards at the side of the intestine towards the 
ventral wall of the body, just before reaching which its cha- 
racter suddenly changes, both in appearance and in structure. 
This ‘‘ penial duct” (fig. 26), as I will call it, is much nar- 
rower than the glandular part or prostate, and is slightly 
curved as it penetrates the body-wall to open by the pores seen 
externally. In appearance, instead of the dull, whitish, uneven 
character presented by the prostate, the penial duct is smooth 
and glistening, due to the fairly thick layer of circular muscles 
which forms its wall (fig. 28). The histological structure of 
the prostate is similar to that of Neodrilus. In fact, these 
prostates are closely similar to those of Acanthodrilus and 
its allies, but are less compact in appearance. 
In front of each prostate is a sac containing long penial chetz 
(figs. 26, 29). Hach sac enters the body-wall immediately in 
front of the penial duct, but, as can be seen in section (PI, 
XVI, fig. 29), crosses the duct in the thickness of the body- 
wall, and opens independently to the exterior just behind, and 
rather to the outer side of it. ach sac is in reality double, 
and each subdivision contains a couple of chet, of which one 
is small (4) and no doubt in reserve, the other being longer (a). 
There appears to be no particular marking or other peculiarity 
about these penial chetz. The ordinary chetz are absent in 
these somites, and the penial chetus occupy their places, as is 
usually the case in Acanthodrilide, 
There are two pairs of spermathece (figs. 19, 30), each 
consisting of two parts, as is so generally the case in the 
