Zoological Society, 311 



the top of a strong hump or protuberance ; the vent being in its 

 centre, as in Doris. It appears, in general, equally five-rayed ; but 

 assumes occasionally, as it also does sometimes in Doris, the appear- 

 ance of being composed of two bifurcated lateral, and a simple ante- 

 rior branch or ray. Its divisions are regularly and beautifully pec- 

 tinate. The caudal fin-like crest begins a little behind it ; and its 

 edge is crisped or irregularly notched and plicate, and even obsoletely 

 ciliate here and there, or fimbriate. In swimming, this crest is stiffly 

 expanded into a broad fin, ending abruptly behind, as in Cuvier's 

 fig. 4. of Scyllaa pelagica (Mem. des Moll.), but with the edge even 

 or entire. 



In a glass of sea- water, in which this animal lived more than six 

 weeks, it had the usual habits of a Doris, but these with more acti- 

 vity : swimming about violently when disturbed or when provided 

 with a fresh supply of water, in which operation the hind part of the 

 body, with the crested fin-like tail, is lashed from side to side with a 

 strong and regular sculling motion ; the fore-part, with the head or 

 veil expanded also to its full dimensions, being at the same time beat 

 with equal force and regularity in a contrary direction, or obliquely 

 upwards and downwards, stroke for stroke ; these parts (the veil and 

 crest) performing thus alike the office of true fins. At night, espe- 

 cially when thus in motion, it appeared most brilliantly phosphores- 

 cent ; the light flashing progressively but very rapidly along the 

 body, especially from all the branchial tufts and the edges of the 

 veil and crest. At other times it remained quiescently adhering to 

 the sides of the glass, or moving slowly up and down as if in search 

 of food ; seeming to use the veil as a feeler, but with the tentacles 

 reflexed. Sometimes it crawled in the usual inverted posture along 

 the surface of the water. It is by no means a shy or timid animal. 



After five or six days, it deposited in the night-time a pale orange- 

 coloured long and narrow riband of eggs, resembling a tape- worm, 

 and loosely coiled up spirally on the side of the glass, to which it 

 was partially attached by one edge. This egg-band was about three 

 inches and a half long and two lines broad, narrowing a little to- 

 wards one end. On two subsequent occasions, at intervals of ten 

 days or a fortnight, it again deposited two similar but smaller bands ; 

 after which, though apparently remaining in full vigour, it retained 

 not more than two -thirds of its former bulk. 



Its mode of swimming perfectly resembles that of the larva of the 

 gnat so common in our English cisterns of rain-water. 



The next paper read was from W. J. Broderip, Esq. In this 

 paper the author proceeds with his descriptions of Shells brought to 

 this country by H. Cuming, Esq. 



In the second volume of the ' ZoologicalJournal' will be found my 

 notice of the Voluta aulica of Solander, a shell which formed one of 

 the principal ornaments of the Portland Museum, of that of M. de 

 Calonne (in the catalogues of which it is noted as unique), of the 

 Tankerville collection (in the catalogue of which Mr. Sowerby 

 speaks of it as " an extremely scarce and fine shell ; the only speci- 



