NUDIBRANCHIATA OF THE L.M.B.C. DISTRICT. 107 
hepatic cecum by a small terminal aperture, surrounded 
by a distinct sphincter muscle, so as to allow the lumen of 
the hepatic cecum to communicate with the cavity in 
which the thread cells lie, and therefore with the exterior 
when the sphincter is relaxed. 
Flabellina drummondi, Thomp. 
Taken at Hilbre Island on 6th September, 1888, and on 
16th May, 1889. In the cerata of this species we find the 
cnidophorous sac elongated, overlapping the upper end 
of the hepatic cecum and joined to it by a long slender 
recurved tube. 
Coryphella rufibranchialis, Johnst. 
We have taken this species at Hilbre Island on the 
6th September, 1888, and on 2nd March and 16th May, 
1889 (large specimens). 
Cavolina viridis, Forbes. 
We found a specimen of this rare species on the North 
Spit, Puffin Island, near low water mark, on the 18th 
February, 1889. It was 7 mm. in length, and had the 
dorsal process nearest to the middle lne in the seventh 
row on the right side distinctly bifurcated at the tip. 
Cuthona nana, Ald. and Hance. 
We have found this species again at Hilbre Island, on 
Qnd March, on 2nd April, and on 16th May, 1889; and 
also at Puffin Island in April, 1888. 
In this species, as in Galvina picta, the auditory sac 
contains a single large spherical otolith. 
The two specimens found at Hilbre in March resemble 
Eolis pustulata, Ald. and Hane., in one or two points. 
The one specimen has the rose-red colouring of C. nana, 
but shows the pustulate condition of the white granules 
characteristic of H. pustulata; while the second specimen 
