GASTEROrODA. 



109 



tacula, which are thick, cylindrical, long, and having a 

 somewhat small feeler-like appendage at the base; and, 

 according to M. Rang, with eyes at the tips ; the foot has a 

 vesicular or bubble-like apparatus or float, which prevents 

 the animal from crawling, but enables it to float on the sur- 

 face of the water with the shell downwards. — 6 species. 



The species */. communis, pallida, and exigua are found 

 on our coasts and those of Ireland (in consequence of the 

 gulf streams and westward winds), but they are inhabitants 

 more especially of mid-ocean. Other species are brought 

 from the Mediterranean and Madagascar. They are seen 

 in immense numbers together floating on the sea, suspended 

 by the curious float, and they emit a violet-coloured liquid 

 when they are touched or injured. The eggs are attached 

 to the under side of the float ; and Dr. Coates remarks, 

 u that the animal seems to occupy considerable time in the 

 deposition of its eggs, the bags nearest to the extremity of 

 the float being constantly found empty, while the central 

 ones contain young shells fully formed, and those towards 

 the animal are filled with eggs."* This float is too large 

 to be drawn into the shell ; it remains on the surface of the 

 water ; indeed it is said that the animal has not the power 

 of sinking.f 



Family 15. — S TYL1NA CEA. 



The animals of this family have a small rudimentary 

 foot, a cup-shaped mantle, and two round thick tentacula. 

 The shell is glossy, globular, irregular, with a tapering 

 pointed apex; the aperture is oval, pointed above, the 

 lips not connected, the outer lip sharp and sinuated, or 

 waved; no operculum. — Marine. 



* Forbes's British Moll. 



t Woodward's Recent and Fossil Shells. 



