654. C. H. MARTIN. 
forward, far more slowly than the ciliate embryos of Acineta 
papillifera, halting at intervals on their posterior end to 
make a half left turn. In the case of some embryos which 
were seen to escape at 5 p.m., they were almost stationary at 
6.55 p.m., and were fixed at 7 p.m. 
The embryos attach themselves by their posterior end, and 
the proboscis makes its appearance as a projection on the 
anterior ventral surface. 
Claparéde and Lachmann’s drawings (11, a and b), seem to 
show very faithfully the appearance of the free living ciliate 
embryo; (a) being a ventral view, and (b) a lateral one. 
I have never succeeded in observing the escape of the 
ciliate embryo from the vermiform individual, though I have 
often seen the cilia slowly beating in the large earlier embryo, 
and on one occasion | saw six small embryos in very active 
motion in a vermiform individual. The shape and size of the 
ciliated embryo in the latter case coincided with those of the 
normal free embryos developed from a proboscidiform indi- 
vidual. There appears to be, however, a constant difference 
between the number of ciliated embryos in the vermiform 
and the proboscidiform individuals ; in the former I have 
never seen more than six embryos, whereas in the large indi- 
viduals of the latter the number may be great—over 30 
(Allo, fe 0): 
I believe that the embryos of both the proboscidiform and 
the vermiform individuals always gives rise on fixation to 
young proboscidiform individuals, since while small probosc- 
idiform individuals of about the same bulk as the ciliate 
embryo are often met with (Pl. 15, fig. 12), the smallest 
vermiform individual I have seen with a well-developed stalk 
measured 115 long by 18 at its widest point. 
