72 systematic arrangement 



2. Aricia. 



Shell ovate, smooth, polished ; spire hidden ; lips toothed ; canal 

 recurved ; front of pillar flat, or nearly so, and cross-ridged, with a 

 distinct fold in front, separated from the teeth by a deep groove. 



a. Margin of the shell pitted on the upper edge. 



1. A. erosa, Fig. Moll. t. 33. f. 1, 2 ; Adams, Gen. Moll. t. 261. f. 2. 



b. Margin entire ; teeth of both lips extended more or less over the 



base. 



2. A. annulus, t. 34. f. 6. 



3. A. Moneta, t. 34. f. 9. 



4. A. caput serpentis, t. 33. f. 4. 



5. A. Caurica, t. 261. f. 1. 



6. A. variolaria, t. 34. f. 3. 



7. A. rufa, t. 35. f. 1-3. 



8. A. cribraria, t. 34. f. 2. 



c. Margin entire; teeth of inner lip very small, forming a slight 

 ridge ; front of columellar lip slightly concave, produced, and 

 toothed internally. 



9. A. angustata. 



3. Naria. 



Shell ovate, polished ; spire hidden ; lips toothed ; front of the 

 columella narrow, dilated into a sharp-toothed ridge, with a distinct 

 fold in front, separated from the teeth by a deep groove. 



1 . N. irrorata. 



** Inner lip without a distinct fold in front. 

 4. Trivia. 

 Shell subglobose, cross-ribbed ; aperture toothed ; front of the 

 pillar internally concave, ribbed, without any distinct fold in front. 

 Rostrum short. Tentacles elongate, linear. Eyes basal, sessile. 

 Mantle produced, nearly covering the shell, smooth externally. Foot 

 elongate, truncated in front, elongated and much produced behind the 

 shell. Siphon elongate, produced in front. 



a. Mouth wide ; outer lip slightly infexed ; shell equally ribbed. 



1. T. australis, t. 34. f. 7. 



b. Mouth narrowish ; outer lip wide ; ribs of back subequal, linear. 



2. T. europ«e, t. 36. f. 1 ; Sari, t. 36. f. 6 ; Forbes A'- Hartley, B. M. 



\. N.N. f. ."», 7, COp. Adams, Gen. Moll. !. 28. f. r>. 



