170 APHRODITA. 
I conjectured that the last segment, along with a pair of scales, 
might be originally deficient. Whether it was truly so, two minute pro- 
jections were observed advancing at the posterior extremity in a fortnight. 
Piate XXIV. 
Fic. 13. Aphrodita velox, enlarged. 
§ 5. Apnropira ARctA.—Plate XXIV. Fig. 14. 
Length nine lines ; breadth the seventh or eighth part of the 
length. Form cylindrical, or nearly so. Head small, reddish, with [four] 
eyes indistinctly exposed. Antenne two. Styles terminating the body 
two. One which had been mutilated and nearly renewed. The body con- 
sists of numerous segments. It is covered by about sixty pair of scales, 
in two distinct rows, separated by a narrow interval down the back of 
the animal, and there exposing a small portion of the segments to view. 
Colour universally dingy white ; a darker internal portion towards the 
anterior, denoting the position of the proboscis. 
This is a sluggish creature, reposing constantly on a leaf of green 
fucus. 
It was taken in Shetland, and survived above a month. 
Piate XXIV. 
Fig. 14. Aphrodita arcta—Narrow Aphrodita—enlarged. 
§ 6. Apnropira AcuLEatA—The Sea Mouse.—Plate XXIV. Figs. 15, 16. 
Though this subject is incorporated in the genus Aphrodita by natu- 
ralists, and commonly presented as the type of the race, no animal bears 
less external resemblance to the preceding forms, which are all suffi- 
ciently defined to shew that they are kindred. 
The aspect of this species, however, is so peculiar, that it cannot be 
mistaken. It is the most brilliant of all the lower animals dwelling in the 
