DOLABELLA. 



Shell rather oblong, somewhat arched and hatchet- 

 shaped; narrow^ thick, callous and suhspiral at the 

 posterior extremity; increasing in width, and becoming 

 flatter and thinner towards the front: the shell is almost 

 entirely covered with a strong, horny, yellowish epidennis, 

 over which the posterior edges of the shell are reflected. 



Several recent species of this Genus are known, 

 which, we believe, are all included under the Linnean 

 name Bulla dubia, but which, upon comparison, will be 

 easily distinguished from each other ; the one of which 

 we have shown both sides agrees with Lamarck's 

 description of D, Rumphii; we have another lying before 

 us, in which the posterior callosity is much more expanded 

 and thinner; and the disk is obliquely grooved, which 

 appears to be a very distinct species. The Dolabellae are 

 inhabitants of the Indian Ocean, they appear to prefer 

 quiet situations, where they cover themselves thinly with 

 mud. 



Not known in a fossil state* 



