RISSOA. 43 



I observed it in the collections of MM. Susini from 

 Corsica and of M. Mace at Cannes. 



It is exceedingly agile both in creeping and swimming, 

 and spins a delicate thread of attachment. Mr. Clark 

 states that this species (i is a dwarf, nearly ribless R. 

 inconspicua. ,} The latter, however, has a much narrower 

 base, the spire is more tapering and sharp-pointed, and 

 the outer lip is furnished with a rib ; and the shell is 

 never so thin in proportion to its size, and is invariably 

 sculptured. I have carefully compared the young and 

 adult of each species, in order to satisfy myself as to their 

 distinctness. Truncatella fusca of Philippi is allied to 

 the present species. 



22. R. ful'gida*, Adams. 



Helix ful gidus, Ad. in Tr. Linn. Soc. iii. p. 254? R. fulgida, F. & H. 

 iii. p. 128, pi. lxxxi. f. 1, 2. 



Body whitish, with more or less of a yellow hue, and micro- 

 scopically suffused with flake-white points : mantle not exhi- 

 biting any filament : snout short, bifid at the point : tentacles 

 cylindrical but somewhat compressed, rather short, sparingly 

 and minutely setose : eyes large in proportion, on small pro- 

 tuberances of the tentacles, at their outer bases : foot flexible, 

 usually rounded in front and bluntly pointed behind; sole 

 grooved lengthwise down the middle on the posterior half. 

 Neither Mr. Clark nor myself could detect any distinct oper- 

 cular cirrus or appendage — although he says, " in some speci- 

 mens I have fancied I saw a very short blunt one." 



Shell conic-oval, inclining to globular, rather thin, semi- 

 transparent, and glossy : sculpture none, even under the micro- 

 scope : colour pale yellow or creamy, with two reddish-brown 

 bands on the body- whorl, one narrower just below the suture, 

 and the other broader below the periphery; there is also a streak 

 of the latter colour on the base ; the penultimate whorl is mostly 

 reddish-brown: spire very short: whorls 4, tumid; the last equals 

 three-fourths of the spire, and is somewhat expanded towards 

 the mouth : suture deep : mouth nearly round : outer lip thin : 



* Shining. 



