46 Dr. W. B. Benham on some Javan Perichetide. 
though there is a slight difference in the two drawings; the 
diverticulum in the figure (pl. i. fig. 25) of the former is 
relatively longer and narrower than in Ude’s figure (pl. iv. 
figs. 8, 9) or in my own. Is this a specific difference, or is 
it merely due to a difference in functional activity ? Cer- 
tainly Horst’s drawing more nearly resembles the spermatheca 
of the worm described above (P. Willey, sp. n.), and Ude’s 
resembles Rosa’s P. operculata, which is regarded as a 
synonym of P. capensis. 
Another character which always has to be noted in the 
Pericheetide is that presented by the prostate. In the present 
worm it is more than three times as long as wide (its actual 
measurement is 7X2 millim.), and consists of very many 
rounded notched lobes, forming as a whole a flattened, slightly 
yellowish organ, which extends through segments 16-20. 
From near the middle of its inner border the penial duct issues, 
at first narrow, with thin wall, but soon becoming wider 
and having muscular walls. It opens into a circular flattened 
“bursa,” as is figured by Horst for P. capensis. 
Thus the only differences between this present worm and 
P. capensis appear to lie in the position of the spermathece 
(and it is to be noted that in one of Horst’s specimens a third 
spermatheca occurred on one side of the worm in segment vii.) 
and in the character of the male pore; and although my worm 
agrees in nearly all other features with P. capensis or with 
P. operculata, yet, as these two points are regarded as of 
specific value, | give a new nameto this worm. Nevertheless 
I conceive that it is quite possible that it may be a hybrid or 
an abnormal specimen. 
The five species, P. capensis, P. operculata, P. tjibode, 
P. sexta, and P. Willey?, ave very closely allied, and came 
from the same neighbourhood; to these must be added P. Ten- 
katet, Horst, from the island of Soemba. They all have two 
pairs of spermathece, with peculiarly modified diverticulum : 
they all have a much lobed prostate. All agree pretty well in 
size—from 50 millim. in P. tibode to, more commonly, 
100 millim., as in P. capensis, the largest being 140 millim. 
(P. Willeyi). The number of segments, too, does not vary to 
any great extent—again, P. operculata forms the first and 
lowest of the series, with its sixty segments; the others have 
one hundred or a few more. 
The number of cheete in a postelitellian ring appears to be 
about fifty to fifty-six (Rosa does not give any number for 
this region), which is reduced to about thirty-eight in the 
region of the spermathece. 
