334 



THE OCEAN WORLD. 



products of digestion, is termed the anal tube. The tentacles of the 

 bronchial tube seem to be possessed of exquisite sensibility. When 



Fig. 138. Telllna radiata (Linnseus). 



touched, the animal draws in its syphon, and only puts it forth anew 



when the danger has passed. 



The species of Donax are very 



numerous, especially in the 



Asiatic and American seas. 



Among the European species 



we may mention Donax ru- 



gosus (Fig. 136) and Donax 



denticulatus (Fig. 137). 



Next to Donax naturalists rank the genus Tellina, which includes 

 many species of very minute shells, all remarkable for their beauty of 

 form, and for their brilliant and varied colours. One of these, called 

 the Eising Sun (Tellina radiata), is represented in Fig. 138. The 



Fig. 139. Tellina virgata (Linnaeus). 



Fig. 140. Tellina sulplmrea (Lamarck). 



Fig. 14] . Tellina donacina (Linnaeus). 



Tellinas are found in every sea ; the French coast furnishes many 

 species : examples, Tellina virgata (Fig. 139) and Tellina sulphur ea 



