Dr. W. B. Benham on some Javan Pericheetide. 43 
pairs of spermathecal pores, between segments vii./viii. and 
viii./ix., and separated by fourteen chete. 
Internal Anatomy.—It may be noted that the gizzard 
occupies segments vill., ix., and x., and is of the same shape 
as in P. capensis, viz. bell-shaped. The sacculated intestine 
commences as usual in segment xv.; there is a pair of caca 
in segment xxvi., their blind ends reach to the twenty-third 
segment. ‘he septa vill./ix. and 1x./x. are absent. 
The sperm-sacs have the usual position. 
The large spermathece lie in segments vil. and vill. The 
tubular diverticulum is spirally coiled or merely curved, just 
as Ude has observed to be the case in P. capensis. As a 
matter of detail, those of segment vil. were coiled, those 
of the eighth were more simply curved, apparently because 
of the greater space in which the organs lie. When spirally 
coiled the terminal saccule lies in the axis of the spire, as in 
fic. 4; when curved it is bentssharply round. 
The prostate is multilobate, but the lobes differ in shape 
from those of P. capensis; they are longer, less rounded at 
their ends, and more flattened. The organ is about twice as 
long as it is wide, and is more opaque, of a more dead white 
colour than in the species next to be described. The penial 
duct does not open into any apparent bursa. 
It will be seen that in one or two points P. Walley? 
resembles P. operculata, Rosa, and P. capensis, Horst; but 
it differs from both in the position of the spermathece, 
and, in the single specimen at my disposal, in the size and 
coloration. 
In the character of the generative pore it resembles to 
some extent P. operculata; but I confess that I do not lay 
great stress on this, for I believe that the ‘ operculum” ex- 
ternally and the absence of a “ bursa”? internally are related 
and depend on whether the penial duct is or is not fully 
introverted. 
I am inclined to lay considerable stress on the colour and 
dimensions of the worms, for in our endemic forms these 
characters are very constant ; and in other groups of animals 
colour—within certain limits, varying in different groups—is 
a useful specific character. We have yet to learn how far the 
size of the prostate and the size of the diverticula of the sper- 
mathece are liable to variation, either in relation to functional 
activity or to other circumstances, though I believe it would 
be useful to have careful measurements of the length and 
breadth of the prostate, for probably the proportions of the 
organ remain fairly constant. Further, the shape of the lobes 
