two rare British Nudibranchs. 381 
loosened its hold of the side of the glass vessel and progressed 
slightly by means of these contractions. Again, after 
floating foot upwards for some time, it would wriggle to the 
bottom and immediately gain a footing. 
My specimen was quiet during the day. In the morning 
I found that it had crawled out of the dish where it had been 
placed overnight. ‘This was done constantly, and indicates 
nocturnal habits. During the three weeks that I kept my 
specimen no spawn was “deposited ; hence probably it was 
immature. 
As regards the significance of these observations. Con- 
tinual changes of form in the pleuropodial papille during life 
have been noticed by Dr. Norman in his species, LZ. Hancocki* 
The complete similarity, however, both in characteristic 
form and power of coordinative movement possessed by these 
papillae in common with those of the “ calyx-sheath ”’ appa- 
rently escaped him, and is an additional argument in favour 
of the view advanced by Mr. Garstang J, ‘that such sheaths 
contain a ‘ pleuropodial element.” 
Hancockia eudactylota, Gosse. (Pl. XVII. fig. 3.) 
A specimen of this species was dredged last summer (1891) 
on Delesseriain Plymouth Sound, as I have already recorded f. 
Mr. Hunt, the original discoverer of this form, dredged the 
only previous British specimen on the same Alga in Tor Bay 
in 1877. ‘This was described by Mr. Gosse § under the name 
Hlancockia eudactylota. In 1886 Prof. 'Trinchese, apparently 
in ignorance of Gosse’s paper, described (“ Ricerche Anato- 
miche sul Genere Govia” ||, 1886) four specimens dredged 
near Naples, defining them as two species of a new genus, 
Govia rubra and G. vircdis. Although the internal anatomy 
of Hancockia is unknown, it seems probable that the genera 
Govia and Hancockia will be united, as indeed has been done 
by Dr. Norman in his “ Revision”? (this Journal, vol. vi. 
1890, pp. 79, 80). Carus (‘ Prodromus Faune Mediterranee,’ 
vol. u. pt. 1, p. 208) writes the genus Govia, Trinch., adding 
in brackets (//ancockia, Gosse). 
The Plymouth specimen was about a quarter of an inch in 
* Norman, Ann. & Mag. Nat. Hist. 1877, xx. p. 518. 
These Complete List of Opisthobranchs at Plymouth, ” Journ, Mar, Biol. 
Assoc. (n. 8.) 1. no. 4, p. 430. 
je“ The Occurrence of Hancockia at Plymouth,” ¢bed. (n.s.) vol. ii. 
no, 2, p. 198. 
§ Ann. & Mag. Nat. Hist. ser. 4, vol. xx. 1877, p. 316. 
|| Mem, della R. Ace. delle Sc. dell’ Instituto di Bologna, ser. 5, vol. vii. 
