AND HABITS OF THE AMMOCHARID®. 253 
nearly all had disappeared. The spermatozoa (PI. 25. fig. 19) 
were found to be of the form figured by von Drasche (12. pl. ii. 
fig. 14). Three other specimens in the same aquarium, with 
branchie fully displayed, were apparently quite unaffected by 
what was taking place ; and this observation was one evening in 
the following July supplemented and confirmed by a colony of 
English specimens which had, a few months before, settled in 
another aquarium. About 7.30 p.m. several males discharged 
spermatozoa, the swarms of which were still close to their 
respective tubes, and readily recognized by the cloudy masses 
speedily diminishing. Shortly afterwards, several followed 
exactly the same course, and about the same time three females 
discharged ova. The latter procedure differs somewhat from 
the former, in that little more than the anal extremity is 
exposed from the anterior end of the tube. A quantity of fecal 
matter was first expelled, and then the ova were, as before, 
discharged through the two pores at the anal extremity, but 
much more slowly than the spermatozoa and enveloped in 
albumen, sc that while issuing the discharge had a thread-like 
appearance. When deposited, there was formed a small jelly- 
like mass near the tube; and the contrast between the energetic 
movements of the male and the quiet discharge of the female was 
very marked. In one case a male, whilst discharging sperma- 
tozoa, actually stirred-up with his tail a mass of ova which had 
been deposited by a neighbour. With very few exceptions, all 
the worms discharged their genital products within an hour or 
two, and as to the cause of this simultaneous action it may be 
that the swarm of spermatozoa from the first animal which 
discharges acts as a stimulus. Hornell has observed (22. p. 18) 
similar synchronous emission in the case of Branchiomma 
vesiculosa. 
A few days after spawning, nearly all the worms cut off about 
10 mm. of the anterior end of their respective tubes. The anal 
pores (a.p., Pl. 25. fig. 20) are very striking and interesting 
structures, their lumina being lined with very large, regular, 
radiating, cylindrical, transparent cells (a.p., Pl. 24. figs. 10 & 11), 
which refuse stain when treated with hematoxylin and eosin. 
Possibly their function may be glandular and connected with 
the supply of albuminous matter, since they appear to be most 
fully developed in, if not entirely confined to, the females. I 
have been unable definitely to determine at what stage in the 
