DONAX. 341 



an elongated or ligulate band. Internally the shell is 

 often punctured with small holes. 



Shells of the genus Bonax are so strongly characterized 

 by their form, that the genus remains nearly as entire as 

 in the time of Linnaeus. Their construction is singular, 

 resembhng a wedge, broad and thick at one end, and 

 gradually tapering towards the other ; a construction which 

 considerably assists the inhabitant in excavating his sub- 

 terranean abode. The hinge is furnished with two small 

 teeth, and the anterior slope is generally gaping. To 

 remedy this apparent inconvenience, a ligament is placed 

 near the fissure, which prevents the valves from separating 

 when the indwelling mollusk has occasion to expand them. 

 The peculiar construction of the shell, the slight adhesion 

 of the hinges, the gaping of the valves, the ligament which 

 prevents them from separating, and the facility afforded by 

 all these of readily procuring food or enabling the mollusk 

 to change his place of abode, afford, when compared with 

 the dissimilar construction of other shell-fish, convincing 

 proofs of appropriate design. The name Bonax is derived 

 from a Greek word, signifying a reed ; and a flying reed is 

 used by the ancients for an arrow. The name aptly describes 

 the shape, which resembles the head of a javelin. The 



