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cise use of which has not yet been clearly ascertained, 

 though Lamarck considers them as supports to the 

 animal's body. Among the many characteristic differ- 

 ences that exist between this genus and that of the 

 G. Anomia, may particularly be pointed out, that in it 

 the perforation is always on the smaller valve, which 

 is attached to the opposite one by means of a cardi- 

 nal ligament, while in the Terebratulae the hole is al- 

 ways in the larger valve, which is connected by teeth 

 at the hinge to the smaller one. From the locality of 

 the fossil species of this genus, these shells may be pre- 

 sumed to inhabit the sea at a great depth. Lamarck di- 

 vides this family into two sections, those having the 

 valves smooth, and those having them longitudinally 

 grooved. He has enumerated twelve species, but a 

 greater number is known, though not all of them de- 

 scribed by any author. 



Shells smooth, without longitudinal grooves or strioe. 



Terebratula vitrea Terebratula pisum 



dilatata globosa 



Terebratula rotunda. 



