PLATE L. 
PAOB 
Figs. 1, 2. BuLLiopsis INTEGRA Conrad 197 
1. Ventral view of adult individual. St. Mary's River. 
2. Ventral view of young individual. Same locality. 
Fig. 3. BuLLiopsis QUADRATA Conrad 198 
3. Ventral view. St. Mary's River. 
Fig. 4. BULLIOPSIS MARYLANDicA Conrad 198 
4. Ventral view. Cove Point. 
Figs. 5-7. CoLUMBELLA (AsTTRis) COMMUNIS (Conrad) 199 
5. Ventral view. Cove Point. 
6. Ventral view. St. Mary's River. 
7. Ventral view of another specimen. Same locality. 
Fig. 8. COLUMBELLA CALVERTENSIS n. Sp 200 
8. Ventral view. Plum Point. U. S. National Museum. 
Figs. 9a, 9b. Mukex (Pterorhytis) conradi Dall 200 
9a. Ventral view. St. Mary's River. (After Dall.) U. S. National 
Museum. 
9b. Apical view of the same specimen. (After Dall.) 
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