560 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
trawl—possibly they are fastened by the mother amongst 
rocks in inaccessible places. 
The ova of H. cirrosa are grouped in characteristic 
strings during the spawning (PI. I, fig. 2). One female 
deposits about 30 of these racemes, each consisting 
of 25 to 30 eggs, so that the total number spawned 
is about 800. The whole process of spawning lasts over 
several days, the racemes being. produced at intervals 
during this time. According to Joubin, H. aldrovandi 
will devour its own spawn if disturbed during the laying 
process. 
The spawn will now be described, so that the order of 
events in spawning may be understood. The egg itself 
is enclosed in a semi-transparent horny ege case (fig. 2, 
h. c.), which is secreted by the follicular epithelium before 
the expulsion of the ovum. Anteriorly this egg case is 
drawn out into a string for attachment (egg. st.). These 
strings seem first io be twisted together in groups 
of four to six, and then the latter become intertwisted, 
thus forming a main central horny axis, which is coated 
externally by a thin dark layer of horn, and ends in a 
flat disc which adheres to the glass front of the tank 
(fig. 2, A..). The strings of ova are generally attached 
on or near the glass front of the tank, about a foot from 
the surface. The actual deposition of the eggs has been 
observed at the Port Hrin Biological Station by Mr. 
Gravely, of Manchester University, who has kindly 
furnished me with notes on the process for this Memoir. 
For about two hours before the eggs were spawned, 
the Hledone was seen clinging to the glass front of the 
tank, with the small suckers on the proximal part of the 
arm extended. Several very violent waves of contraction 
passed over the body from behind forwards, and several 
jets of watér were directed by the funnel over the 
. 
