158 



POPULAR CONCHOLOGY, 



but nearly round, and smooth, slightly convex on the out- 

 side, and with a small nearly 

 central apex; margin sharp. 

 Animal, with an oval, thick 

 foot, in front two-lobed ; the 

 mantle small, thin, almost 

 flat, in the centre of which 

 is a small, oblique oval, or 

 nearly circular shell ; the gills 

 lie on the right side, pro- 

 longed almost to the left side, umbraiaindica. 

 and consist of numerous fea- 

 ther-shaped laminae; over the furcation of the foot are 

 two longish tentacula, which have the eyes on the inner 

 side. — 2 species ; also fossil. 



The Umbrella Indica is met with in the Indian Ocean, 

 and on the coasts of the Isle of France, and is commonly 

 called the " Chinese Parasol ; " it is thin, transparent, and 

 the interior is marked with rays proceeding from the 

 centre, besides which there is a yellowish stain. The 

 U. Mediterranea is found living in the Gulf of Tarento, 

 and also in the fossil state in Sicily. It is a smaller shell 

 than the preceding, and destitute of the rays. 



Tylodina. Rafinesque. — Shell cone-shaped, either flat 

 or elevated, and the summit having two embryo whorls. 

 The animal can withdraw entirely into the shell ; the head 

 (or chin) is lengthened and bordered; both sides pro- 

 longed into a flat point or tentacle ; two large pipe-shaped 

 tentacula, cloven outwardly, are placed on the neck, on 

 the inner base of which are distinct eyes; the gills are 

 situated on the right side in the form of an oval, double- 

 feathered leaf; behind lie the anal openings, appearing 



