No. 6(l92l) COiMMON MOLLUSCS OF SOUTH INDIA 



143 



In the Philinidac the form of the body is fully specialized for 



burrowing. The shell ha? become thin 

 and small, the spire almost lost and the 

 aperture wide and ear-shaped ; it is 

 embedded entirely and there is therefore 

 no longer a clumsy projecting mass on 

 the back as in Natica and Oliva, to 

 hinder progress through the sand; the 

 lobes of the body are fleshy and smooth, 

 without any projections, the whole an 

 animated plough-share perfect for its 

 purpose of burrowing rapidly. Like 

 Bulla and Cylichna it has a powerful 

 gizzard armed with a crushing apparatus 

 composed of three shelly plates. The 

 Fig. 30. Life appearance of Common species is shapeless in appear- 

 Philine. Sh., outline of ance, a mere mass of white fleshy lobes. 

 shell embedded in mantle. -tj. • . ■ r^ ^ ^ 



it IS not uncommon in soft wet sand. 

 Very different is the beautiful little LOBIGER {Loplwcercidae). 

 This form is often seen in great abundance in quiet sheltered bays 

 where sea-grass prairies are found, as at Tuticorin. At first sight 

 one is inclined to take it for one of the naked forms known as 

 nudibranchs, till the rounded shell is observed. The body is 



Fig. 31. Lobiger viridis showing the oval shell between the two pairs of ' fins' 



(Tuticorin). X 2. 



slender and sluglike, tapering off behind into a long narrow tail. 

 The head bears two flattened tentacles, while on each side of the 

 body proper rise upwards two pairs of great leaf-like lobes or fins, 



