70 Records of the Indian Museum. [VoLnV; 
The aggregate, when it has attained some size, is visible to the 
naked eye as a brilliant white spot. 
A curious condition was found in a number of animals 
examined about the same time of the year as those containing well- 
marked sexual organs. Those to which I now refer had no 
clitellum, and no male organs or male products, but showed 
throughout their extent masses of what was apparently yolk- 
substance. In some cases these masses were large, filling up 
nearly the whole diameter of the body-cavity ; in others they were 
numerous and small, somewhat resembling sometimes the white 
ccelomic corpuscles of the Punjab variety of Navs variabilis [11], 
but showing no nucleus on staining. In a few cases small isolated 
masses of ova were found along with these aggregations of yolk. 
These animals may have been individuals which had _ passed 
through their sexual stage and had failed to get rid of all their 
female products ; or possibly they were the posterior animals of a 
chain, into which, contrary to the usual rule, female products had 
spread; the chain then breaking up, these products had been 
retained by the posterior animals without any means of getting rid 
of them. ‘The eggs would, on this supposition, have entered the 
posterior components of the chain while still small, and would 
have formed their yolk there; eventually breaking up they might 
thus give rise to the appearances observed. 
The spermathecee are two short oval structures attached to 
the posterior face of the septum which delimits the short ceso- 
phagus from the distended crop. This is probably septum 4/5 
(not 3/4, as I assumed in my earlier paper), and the organs are, as 
commonly in the Naidide, in segment v. They open externally 
by a short passage; the pore has somewhat tumid lips. They 
develop rather late, and may be absent after the full develop- 
ment of the ovary and male efferent apparatus. 
The clitellum is situated primarily on segment vi, and spreads 
later half-way over both v and vii, thus coming 
ultimately to occupy a space of about two 
segments. It is a tuberculated area, the 
tubercles being at first minute and discrete. 
Each tubercle appears singly as a small round 
clear particle; but the region as a whole is 
opaque, though not so densely opaque as in 
other Naidide, e.g., Nais and Pristina. The 
clitellum forms late, and may still be absent 
after the establishment of all the other organs. 
The order of development of the various organs 
is thus: testes, ovaries, male efferent appara- 
tus, spermathecee, clitellum. 
The genital sete are the modified sete of 
Hs the sixth segment ‘They make their appear- 
Fic. 4.—Two genital : : 
sete of Chetogaster ance during the time of development of the 
orientalis. male efferent apparatus ; thus in a specimen 
in which the funnel was not yet ciliated, and 
