MARINE MOLLUSCS 



207 



will soon rise to eject it, and may then be shut out from the lower 

 part of the burrow by sharply driving a spade below it. This is 

 undoubtedly the best method of securing perfect specimens for 

 study or preservation, but fishermen often obtain large numbers, 

 either for food or for bait, by suddenly thrusting a long hook down 

 into the gaping shells, and then pulling them out. This method 

 always does injury to the soft body of the animal, and often 

 damages the shell, but answers the fisherman's purpose exactly. 



We give illustrations of two shells belonging to the typical 

 genus (Solen), including one on Plate V. ; also a British repre- 



Fio. 140. 1. Solen ensis. 2. Cerati-solen legumen. 3. Solecurtus 

 candidus 



sentative of each of two other genera of the family Cerati-solen 

 and Solecurtus, the latter of which, as the name implies, contains 

 shorter species. 



The next family the Tellinidce contains a number of well- 

 known molluscs that burrow into sand or mud, and are enclosed 

 in shells that are often very prettily marked; and although the 

 family includes several genera, all may be recognised by the 

 following general features. The shell is compressed, composed of 

 two equal valves, with little or no gape, and the ligament situated 

 on the shortest side. The central or cardinal teeth never exceed 

 two in number in each valve, and the adductor impressions are 



