HABITS OF MOLLUSKS. 493 



rolls and leaps over and over. It is, however, far more 

 timid and suspicious than Strombus, which has a bold dis- 

 dosition. On the low sandy beach, near the mouth of 

 the Lundu River, in Borneo, dead shells of Rostettaria 

 rectirohsis are numerous, but generally in a very imper- 

 fect condition. At the small fishing village of Samahrtan 

 I inspected a large heap of these shells, which the 

 Malays had brought together for the purpose of turn- 

 ing them into lime. On enquiring of these poor fisher- 

 men whether it were possible to obtain them in a living 

 state, we were informed that they never procured them in 

 their nets, but that they lived in deep water at a consider- 

 able distance from the shore. The animal of Rostettaria 

 fissa does not differ from that of Strombus, and is of 

 a dull brown colour, varied with lighter brown. It is, 

 however, one of the most lively among Mollusks, jumping 

 several inches, and throwing itself about with the most 

 astonishing activity. It has none of the extreme timidity 

 of the former mentioned species. 



The perfect development of the large, fine, pedunculated 

 eyes of Strombus, together with its very elongated, power- 

 ful, muscular body and foot, and claw-shaped stout, jagged, 

 horny operculum, constitute it one of the most active and 

 intelligent of Mollusks. It is, in fact, a most sprightly and 

 energetic animal, and often served to amuse me by its 

 extraordinary leaps and endeavours to escape, planting 

 firmly its powerful narrow operculum against any resist- 

 ing surface, insinuating it under the edge of its shell, and 

 by a vigorous effort throwing itself forwards, carrying its 

 great heavy shell with it, and rolling along in a series of 

 jumps in a most singular and grotesque manner. 



