CONCHOLOGY. 
CLASS I. 
ANNULATA. 
AnImaAt 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 
antenne; 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 
branchie, which are sometimes imperceptible. Four Families. 
FAMILY I. 
Dorsatta. Two Genera. 
1. Genus 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. Pl. V. 
Animal. See Arenicola. 
a 
