HABITS AND ASPECT OF ANCILLAHIA. 515 



The nature of the animal of Ancittaria appears to be 

 not very well understood. M. Rang observes : " Animal 

 furnished with a lobe of the mantle covering the shell, in 

 other respects unknown." (Manuel de Mollusques, p. 227.) 

 Mr. Gray, founding his opinion on the figures of M. Quoy, 

 observes: " The shell is nearly sunk in the very large ex- 

 panded foot of the animal, which is deeply cut in on each 

 side in front. The siphon alone is exserted." It appeared 

 to me, however, when examining these animals, numerous 

 living specimens of which were dredged by us on the east 

 coast of Africa, that the lateral lobes or processes which 

 partially envelope the shell, are precisely analogous to 

 those of the Sulla, and are as much entitled to be called 

 the mantle, as are the loose expanded lateral folds which 

 cross upon the back of the Aplysia. These alar expan- 

 sions of the mantle are enormously dilated, the right one 

 is generally longer than the left posteriorly, and both curl 

 upwards and inwards during the ordinary progression of 

 the animal, and folding themselves on the shell, almost 

 entirely conceal it from view. At the anterior part, they 

 are in close juxta-position, in the middle they slightly 

 overlap each other, and posteriorly they are rounded and 

 open, and projecting beyond the spire, form a loose, open 

 sac. Anteriorly, the foot is produced, as in Natica and 

 Sulla, forming a cephalic disc, which however is divided 

 by a deep furrow or groove into two triangular lobes, and 

 separated from the lateral portions of the foot by deep 

 lateral clefts or fissures ; behind, the foot is slightly cleft 

 or bilobate, and below, it is furnished with a furrow in the 

 median line, and is smooth, wide, and provided with a 

 slimy, mucous secretion, another peculiarity in which it 



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