GALEOMMA. 



Turton, 



■ 



TESTA tenuis, plerumque ovalis, sequivalvis, 

 aequilateralis, margine ventrali hiante ; dente 

 cardinal! in utraque valva unico ; impressionibus 

 muscularibiis diiabus, subapproximatis, impres- 

 stone musculari pallii interrupta, sinu nullo ; 

 ligamento parvo, duplice, parte interna denti 

 cardinal! propinqua, parte externa fulcro pro- 

 rainenti affixo. 



First discovered by Dr. Turton and described by bim in 

 the Zoological JournaL A figure is there given from the 

 only specimen that had then occurred; several have, 

 however, been found since, and we possess four or five 

 species from various localities. 



Shell thin, generally of an oval shape, equivalve, and 

 equilateral, with the ventral margin widely gaping : there 

 is a single small cardinal tooth in each valve : the muscu- 

 lar impressions are two, they are lateral, though somewhat 

 approximated : the muscular impression of the mantle is 

 interrupted, but there is no sinus : ligament small, double, 

 one part internal, close to the cardinal tooth, the other 

 part external and fixed to a rather prominent fulcrum. 



The animal has been found alive; we have, however, 

 so little acquaintance with it that we do not venture to 

 suggest anything about its affinities; we are informed, 

 however, when living it is affixed to stones with the valves 

 spread widely open. 



Mr. Gray has obligingly favoured us with the follow- 

 ing descriptive observations on this shell and its ani- 



