MALACOZOA. GASTEROPODA. TECTIBRANCHIATA. 67 



1. Chiton fasciculdris. Shell elliptical, moderately 

 convex, subcarinate; the valves shagreened; the mar- 

 ginal band with eighteen tufts of greyish hairs. Fasci- 

 culdris, having fasciculi or tufts. 



2. Chiton margindtus. Shell elliptical, moderately 

 convex, subcarinate; the valves shagreened, varying in 

 colour; the marginal band granulated, with alternate 

 dusky and whitish spots, and edged with minute spinclets. 

 MargindtuSy having a margin or edging. 



3. Chiton cinereus. Shell elliptical, moderately con- 

 vex, carinate ; the valves shagreened, with distinct growth- 

 lines ; the marginal band narrow, minutely reticulated, 

 with the edge spinulose. Cinereus, ash-grey. 



4. Chiton fuscdtus. Shell oblon go-elliptical, a little 

 narrower anteriorly ; carinate, the valves shagreened with 

 irregularly disposed granules ; the marginal band granu- 

 late, with a membranous border. Fuscdtus, dusky. 



5. Chiton Icevigdtus. Shell broadly elliptical, a little 

 narrower anteriorly, subcarinate; the valves minutely 

 granulato-striate ; the marginal band smooth. Lcevigdtus, 

 smoothed. 



ORDER VI. GASTEROPODA INFEROBRANCHIATA. 



ORDER VII. GASTEROPODA TECTIBRANCHIATA. 



Respiratory organs composed of branched or pecti- 

 nated laminae, attached along the right side, or on the 

 back, and covered by the mantle, which generally con- 

 tains a shell. 



Gaster6poda Laplysia and Bullcea, Lamarck. Mono- 

 pleurobranchiata, Blainville. Tectibranchidta, Cuvier. 

 Tectus, covered; brdnchice, gills. 



FAMILY I. BULL^INA. 



Body divided into two parts, the anterior often with 

 lateral lobes ; tentacula none or minute ; shell very thin 



