of Gasteropodous Mollusca. 403 



coast may be accounted for by the diiFerence of climate, as their 

 })Osition in shallow pools exposes them a good deal to change of 

 temperature. The spawn forms a small pear-shaped, transparent, 

 gelatinous mass (PI. XIX. fig. 7), with the ova, which are yel- 

 low, imbedded in the centre. Some spawn, deposited by an in- 

 dividual, in a vessel of sea-water, on the 3rd or 4th of June, was 

 hatched, and the larvae swimming about on the 20th of the same 

 month. The larva very much resembles that of the Nudibranchs, 

 as may be seen by a reference to the figure (PI. XIX. fig. 8), 

 having, in that state, a transparent shell and an operculum, which 

 afterwards disappear. A transparent and nearly colourless va- 

 riety of Limapontia nigra is frequently found at Cullercoats, in 

 which the green biliary organ is seen through the skin, as repre- 

 sented in PI. XIX. fig. 5. 



This species, when bruised, has a peculiar sweetish smell, like 

 that of moist sugar, which appears to be derived from the Con- 

 ferva it feeds upon. 



In Loven's ' Index Molluscorum Scandinavise ' this species is 

 made synonymous with Planaria limacina, 0. Fabricius, and P. 

 capitata, Miiller. The former we can find no description of, but 

 the Fasciula capitata of Miiller (Verm. 70) may be either this or 

 a nearly allied species. He describes it however to be spotted 

 with white, which is scarcely a character of L. nigral. 



ACTEONIA CORRUGATA, n. S. PI. XIX. figS. 2, 3. 



Body limaciform, black, depressed, somewhat bulged at the 

 sides, and covered with regular wrinkles like an Avion. On each 

 side of the body there is a slightly elevated ridge, with a few pale 

 tubercular spots. Head carinated at the sides ; each carina being 

 produced above into a short, flat, ear-like tentacular process, 

 which is whitish. The eyes ai-e placed in circular palish spots at 

 the posterior extremity of the ridges. The posterior extremity 

 is obtuse and pale ; there is also a palish spot near the centre of 

 the back. Foot linear. Length one-eighth of an inch. 



Found by Mr. Cocks at Falmouth along with the last, and 

 feeding upon the same Conferva, but rare. 



The genus Acteonia was formed by M. de Quatrefages for a 

 small mollusk found on the French coast. It comes very near to 

 the last, the chief difference being in the form of the carinated 

 ridges at the sides of the head, which in this are produced into 

 flat, blunt, angular projections making an approach towards ten- 

 tacles. 



* Perhaps Fasciola capitafa may be the black species of Pcl/a, described 

 in the ' Ann. of Nat. Hist.' vol. xviii. p. 289, which agrees witli Miillcr's df- 

 scrijjtion in having a ridge along the side, and is also sprinkled with pale 



spots. 



27* 



