344 
CRESSWELL SHEARER 
tank nearest the source of light, although collecting so readily 
on any bright object introduced into the tank itself. It breeds 
continuously through the winter and summer months, and 
those I have kept under observation from day to day lay their 
eggs in several, sometimes as many as five, batches. This 
takes place as the large ovarian eggs ripen. There is some- 
times a considerable time, as much as a week, between the 
laying’ of one batch and the growth of a fresh lot of eggs. 
Once a female has got rid of all its eg’g’s, the germ-cells seem 
completely used up and no more appear and the animal dies. 
The females with eggs seem liable to some disease or 
infection that causes them to swell up and become dropsical, 
the cuticle all over the body becomes puffed out in blebs 
containing fluid, and the animal soon dies. In this state 
they seem incapable of laying their eggs, and when once 
this disease appears in a culture jar it rapidly spreads and 
destroys all the females. 
My mode of procedure in order to obtain eggs in any 
numbers has been to take half-a-dozen two-litre jars of sea- 
water and place a number of females with eggs in each and 
supply them with proper food. The jars are set aside for a 
month or so, at the end of which time it will usually be found 
that one of the jars at least will be crowded with Dinophilus, 
while possibly the others will contain none. 
The manner in which the egg-capsule is formed is some- 
what peculiar, and recalls the way it is accomplished in many 
of the Turbellaria. The female about to lay eggs contracts 
into a round mass and pours out a copious secretion from the 
large mucus cells of the N cuticle, which are especially numerous 
in the region of the ciliated bauds, as shown in fig. 2. In 
this manner the beast is surrounded with a thick coat of 
mucus (fig. 12). The eg’gs are then passed out through a 
small median pore on the animal’s ventral side somewhat 
anterior to the anus. When all the ripe eggs have been laid, 
the animal crawls out of the capsule, with which it has 
surrounded itself, leaving the eggs behind. The mucus after 
a time seems to harden on contact with the sea-water. 
