46 TiMEHRI. 



pools of the savannah streams. The A nodonta ensiformis 

 is easily recognised by its thin and narrow but very elon- 

 gated shell. In Hyria schomburgkiana, the shell is some- 

 what cockle-shapedj swollen and very strongly ribbed. 

 The species of Paxyodon is a very interesting one, 

 growing to a very large size, and attaining a width and 

 length of more than eight inches. The valves become very 

 thick with age, and are often extensively eroded on the 

 exterior, especially in the region of the hinge so as to lay 

 bare the beautiful nacreous substance beneath. As the 

 British and Chinese river-pearls are obtained from closely 

 allied forms, it is likely that the native forms are similarly 

 produ6live, or, at least, may be made produ6live when 

 treated on the Chinese plan of introducing into the 

 living animal, shot, josses etc., between the mantle and 

 the valves, where they become covered by the pearly 

 substance which is continually being secreted by the 

 mantle to form the shell. 



