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 flesh colour. The length of the larger was an inch and two-thirds when crawling, the breadth three quarters of an inch.
PLEUROBRANCHUS PLUMULA.
(1. Viewed from above; 2. from beneath.)
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 keeping 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 contracted, on being put in—the foot being narrowed,
