NUDIBRANCHIATA OF THE L.M.B.C. DISTRICT. 233 
Facelina coronata, Forbes. 
Taken at Puffin Island on the shore in January, March 
and May, and dredged from the Turbot Hole in March, 
1888. 
We have found this species at Hilbre Island since the 
last report on 6th September, 1888, and on 2nd April and 
16th May, 1889. ‘Two of the specimens found on the last 
occasion were of the paler coloured form mentioned by 
Alder and Hancock. 
In his article ‘‘Mollusca,’* Professor Ray Lankester 
states that the supposed communication of the hepatic 
ceca in the dorsal papille, of some of the Ceratonota, with 
the exterior by means of apertures in the apices of the 
papille requires confirmation. Bergh has recently figured 
a continuous tubular passage in the case of Chlamylla 
borealis and Gonieolis typica, and we now give figures of 
sections (Pl. XIL., figs. 4 to 6) showing the exact manner 
in which the communication takes place in specimens of 
Holis from Puffin Island. 
The upper end of each dorsal papilla is occupied by a 
sac containing a large number of cnida or thread cells 
(Pl. XIL., fig. 5, ¢.). This ecnidophorous sac is evidently an 
invagination of the ectoderm, and it communicates with 
the exterior by a small but perfectly distinct and clearly 
bounded aperture at its apex, through which the thread 
cells are sometimes found protruding (see Pl. XII., 
fig. 5, ap.). 
The hepatic cecum (Pl. XIL., figs. 4, 5, 6, h.c.) oceupying 
the greater part of the dorsal papilla reaches nearly to the 
lower end of the sac containing the thread cells, and we 
find in several of our serial sections (Pl. XII., fig. 6, p.) 
a tube with muscular walls leading from the base of 
the cnidophorous sac, and opening into the apex of the 
* <“Eney. Brit.” 9th edition, vol. xvi., p. 659. 
