CONCHOLOGY. 



CLASS I. 

 ANNELIDES. 



CONTAINS FOUp FAMILIES, 



FAMILY I. 



DoRSALi^. Two genera, 



1. Arenicola. Has no shell. One species. 

 A. piscatorium. 



2. Siliquaria. Four species. 

 Shell very thin, conical, tubular, involuted in a loose and 

 irregular spiral manner ; aperture circular, edges sharp, in^ 

 terrupted in the middle by a notch prolonged like a slit 

 through nearly all its length, stopped abruptly at some dis- 

 tance from the summit. 



Sihquaria anguina. Siliquaria laevigata. 



S. muricata. S. lactea. 



S. anguina. The Snake Siliquaria. PI. 33, fig. 4. 

 Shell tapering, undulating, spiral at the extremity. 



S. muricata. The Prickly Siliquaria. 

 Species armed with short spines or prickles ; aperture 

 sometimes margined ; usually of a rosy or pink colour. 



