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 

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

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

 siibterminal, 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 

 branchiae, which are sometimes imperceptible. Four Families. 



FAMILY I. 

 DoRSALiA. Twf Ofenera. 

 1. Genvis Arenicola. 

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

 lengthways on the body. 



Shell. Supposed to be tubular. One species. 

 Arenicola piscatorium. 



2. Genus Siliquaria. PI. V. 



A7umal. See Arenicola. 



3 



