308 GASTEROPODES. 



proportion. Its size doubled in two months, accompanied by a great 

 accession of branchial papillae ; but the colour had faded. 



This animal adheres with remarkable tenacity to the substance sus- 

 taining it. 



PLATE XLV. 



FIG. 2. Eolis tenax. Back, enlarged. 

 3. Belly. 



In a small animal, only two lines long, which at first I rather thought 

 a young specimen, the bunches of papillse were four pair. Those on the 

 shoulders were the shortest, and consisted each of three papillse. 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 Avas 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. EOLIS HYSTRIX The Porcupine Eolis. EOLIS DRUMMOXDI ? 

 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 Edinburgh, where none were ever seen before or since. 

 Being indistinctly seen, they were at first supposed young Asterioe, 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- 



