154 ARTHUR WILLEY. 
those from the stones off Rakaiya, which I have collected in 
much larger numbers, have all been representatives of the 
subdivision Acotylea. 
Several of the latter have laid their egg-plates in my jars. 
There are, among others, two well-marked species of Stylochus, 
both characterised by their uniformly pitted or granular ap- 
pearance, but in one case of an opaque dark ashy colour, and 
in the other of a light brown sandy complexion. As I cannot 
match these with any descriptions in the literature at my com- 
mand, it will do no great harm to refer to the former as S. 
cinereus and to the latter as S. arenosus. 
Stylochus cinereus has a length of 24 to 27 mm., and a 
width of 10 mm. ; tentacles brownish yellow, covered with eyes, 
and 3°5 mm. from anterior margin of body; cerebral eyes ex- 
tending over proximal portion of outgoing nerves; anterior 
marginal eyes extending backwards to level of tentacles; 
margin of body cloudy, but light and unpigmented. 
S. arenosus has a length of 41 to 45 mm., and a width of 
16 mm.; tentacles covered with eyes except the tip, which is 
orange-coloured; tentacles 555 mm. from anterior margin ; 
cerebral and marginal eyesas in 8. cinereus; margin of body 
nearly colourless and translucent; about twelve pairs of in- 
testinal diverticula. 
It is difficult to obtain uninjured examples of S. cinereus, 
as it tears with the greatest readiness while being detached 
from the stones on which it lives. Lacerated examples pre- 
senting a ragged appearance thrive well in aquaria. The 
tendency to laceration seems to be a characteristic of the 
species as much as any anatomical feature. ‘There is a species 
of Cryptocelis (marginal eyes all round body) common here, 
which practises deliberate autotomy, this being one of its 
most characteristic peculiarities. 
S. cinereus laid several irregular patches of eggs on April 
27th. ‘The eggs were disposed in no particular order in a 
somewhat granular gelatinous matrix, each ovum being sur- 
rounded by its own membrane, and measuring 12 to 18, in 
diameter. Before the commencement of segmentation the 
