242 
W. M. Wheeler 
accessoiy cells, but I do not believe tbis to be the case. I am ' 
certain tbat tbe ova do not originate from tbe peritoneal 
epitbelinm of tbe body-cavity diverticula, as Beard ('94) and • 
otbers before bim bave claimed. 
A cross-section tbrougb tbe ovary of tbe rigbt side ofFig. 19 is 
sbown, as it appears under a bigber magnification, in Fig. 21. ' 
Stage 8. 2.5— 3.5 mm long. Tbe body-cavity bas reacbed j 
its nltimate limits and is full of ova in all stages of growtb. In ' 
tbis Stage tbe »uterus« may be packed full of ripe ova ready to be 
discbarged from tbe uterine orifice, wbicb in tbis species is situated 
on tbe dorsal surface of tbe body near tbe cloacal opening. Tbe 
testes, tbougb reduced, are still voluminous; tbere are many mature | 
spermatozoa, some of wbicb bave passed into tbe body-cavity, wbile * 
otbers fill tbe vesiculae seminales. Tbe ovaries are well developed, 
but I bave found no karyokinetic figures to indicate a continued 
Proliferation of oogonia. Doubtless triplet-cells still continue to be j 
given off into tbe body-cavity, and probably tbis emigration of oocytes 
witb tbeir attendant cells may take place tbroughout the life of tbe 
animals eitber continually or intermittently. For obvious reasons tbis j 
emigration is niore difficult of demonstration than tbat wbicb takes i 
place wben the body-cavity is still empty, or nearly empty. In j 
tbis Stage tbe animal is a functional hermapbrodite. | 
Stage 9. 3.5 — 4 mm long. Tbe body-cavity appears to be j 
very large, because the ova wbicb bave distended it during tbeir 
growtb bave been largely discbarged into tbe water and tbe slower 
influx of ova from the ovaries is far from occupying as mucb 
space as the original batch. Most of tbe ova wbicb are still found 
clinging to the peritoneal walls of the body-cavity are well along 
towards maturity. In tbis stage tbe animal is really a func- 
tional female, since tbe testes are nearly or quite exbausted. One 
often find a few ripe spermatozoa floating about in the body-cavity. It 
would seem tbat the animal does not live long after tbis stage wbicb 
is attained by many individuals about tbe last of March. After tbis 
date I found very few mature individuals on the specimens of Ante- 
don wbicb I examined. Tbis matter, bowever, requires further In- 
vestigation at tbe hands of those who may bave an opportunity of 
studyiug the species during the ensuing montbs of the spring and 
Summer. 
Tbe series of stages of M. glahrum here described will be found 
to differ in no important particular from tbe series of M. cirriferum 
