CONCHOLOGY 



CLASS I. 



ANNULATA. 



Animal soft, elongated, vermiform, naked or inhabiting a tube, 

 which it never entirely quits ; the body furnished either with seg- 

 ments or transverse wrinkles; often without a head, eyes or 

 antennae ; without articulated feet, but most of them having in 

 their place bristly retractile knobs, disposed in lateral rows : mouth 

 subterminal, either simple, orbicular, with lips, or in the form of 

 a proboscis ; often with jaws, a knotted longitudinal medulla, and 

 nerves for sensation and motion ; the blood red, circulating by 

 means of arteries and veins : respiration by external or internal 

 branchise, which are sometimes imperceptible. Four Families. 



FAMILY I. 

 DoRSALiA. Two Genera. 

 1. Genus ^reiiicola. 

 Animal. The gills, or respiratory organs dorsal, or disposed 

 lengthways on the body. 



Shell. Supposed to be tubular. One species. 

 A. Piscatorium. 



2. Genus Siliquaria. PI. V. 

 Animal, See Arenicola. 



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