COVERED-GILLED MOLLUSKS. 1S 
The species is usually described as yellowish 
white; but my specimens were both of a rich golden 
yellow, with the central cloud brown, tinged in 
front with red, the underside of the foot of a light 
PLEUROBRANCHUS PLUMULA. 
(1. Viewed from above; 2. from beneath.) 
flesh colour. The length of the larger was an inch 
and two-thirds when crawling, the breadth three 
quarters of an inch. 
In captivity they were sluggish, fond of hiding 
among the fronds and leaves of sea-weeds, but 
at times gliding freely like a Doris. They 
swam on the surface by the foot reversed, and 
then left behind a great wake of clear -viscid 
jelly. They were beautiful animals. After keep- 
ing them in health about a fortnight, I put one 
into fresh water to kill it, for preservation. This, 
however, was not so readily fatal to it as I had 
supposed, for at the end of half an hour I found, 
by its contraction when touched, that it was still 
alive. Probably the mode in which it had con- 
tracted, on being put in—the foot being narrowed, 
