49 



compressed, dilated, and very oblique; tooth on each 

 valve slightly concave beneath to receive the ligament, 

 which is partly internal, and partly, external; valves 

 a little gaping at the upper side, and covered with a 

 brown rayed epidermis, terminating round the margin 

 in a fringed or deep ragged edge, 



Solenimya australis Selenimya Mediterranea. 



AMPHIDESMA. 



T ELLIN A LACTEA. LinnCBUS. 



Sowerby's Genera y No. 9, plate 3. 

 La Marck, on his first examination of the species 

 of this genus, called it Donacilla, considering them to be 

 allied to those of the G. Donax ; but, on a subsequent in- 

 vestigation, he has determined to constitute the present 

 genus of them, as they possess very peculiar charac- 

 ters, and are quite distinct from all other bivalves, par- 

 ticularly in having the valves connected by two li- 

 gaments. Shell generally small, transverse, inequila- 

 teral, suboval or rounded, occasionally a little gaping 

 atthe sides, and, as Sowerby observes, there is a distinct 

 flexuosity in the valves of the larger species. Hinge with 

 one or two teeth, and a narrow cavity for the interior li- 

 gament; the other ligament short and external. 



