308 GASTEROPODES. 
proportion. Its size doubled in two months, accompanied by a great 
accession of branchial papille ; but the colour had faded. 
This animal adheres with remarkable tenacity to the substance sus- 
taining it. 
Piate XLV. 
Fic. 2. Holis tena. Back, enlarged. 
3. Belly. 
In a small animal, only two lines long, which at first I rather thought 
a young specimen, the bunches of papillae were four pair. Those on the 
shoulders were the shortest, and consisted each of three papille. The 
second consisted of two, and the third of the like number. The fourth 
pair consisted each of only one, but the longest of all. 
This was a good example of the multiplication of these organs. The 
other specimen, when small, on being first obtained, had six or seven in 
each bunch on the shoulders. 
11. Eons uystrix— The Porcupine Eolis——Eous DrummMonpi ?— 
Plate XLV. Figs. 4, 5, 6. 
This species is distinguished by its peculiar habits. The Doris is a 
sluggish animal ; and less animation is displayed by the whole tribe than 
is usually seen among the lower animals. ‘Their form, indeed, is diversi- 
fied, but their habits are nearly the same. It is otherwise, however, with 
the present subject, which is fierce and active, and clearly demonstrates 
very decided propensities. 
On August 18. 1821, I took six specimens from among a colony 
under a very large stone, on the southern shore of the Forth, some 
miles east of Edimburgh, where none were ever seen before or since. 
Being indistinctly seen, they were at first supposed young Asteriz, but 
when committed to a suitable vessel of sea- water, they soon shewed their 
peculiar form. 
The largest extended eight or nine lines from the tip of the tenta- 
