of mollusca. 69 



1. Amphiperas. 



Shell ovate, ventricose ; the outer lip broad, inflexed, rounded, 

 crenulated ; extremities short ; front of columella rounded ; mantle- 

 edge simple. Foot large, expanded. 



1. A. ovum, t. 29. f. 1, 2, t. 30. f. 3, t. 105. f. 4. 



2. A. torile, t. 33. f. 3, 5. 



3. A. dentatum, t. 86 a. f. 6, t. 261. f. 3. 



2. Calpurnus. 



Shell fusiform ; outer lip inflexed, toothed ; ends short, curved ; 

 hinder with a tooth on the inner side ; front of columella expanded 

 beneath. 



* Outer lip broad. 



1. C. verrucosus, t. 36. f. 2, t. 85 a. f. 5. 



** Outer lip inflexed, rounded, narrow, toothed. 



2. C. adriaticus, t. 105. f. 7. 



*** Outer lip slightly inflexed, narrow, keeled externally, with 

 edge shelving inwards. 



3. C. pyriformis, Sow. 



3. Ultimus. 

 Shell fusiform ; outer lip thickened, inflexed, toothless ; extremi- 

 ties short ; front of the columella flattened ; hinder part with a fold, 

 obliterated by age. Rostrum moderate. Tentacles linear, subulate, 

 elongate. Eyes subsessile, basal. Mantle lobes expanded over the 

 shell, smooth externally. Siphon produced. Foot elongate, rather 

 truncate in front, produced behind. 



1. U. patula (Volva p.), Forbes fy Hanley, B. M. t. N.N. f. 1-4. 



4. Radius. 



Shell spindle-shaped ; the outer lip thickened, slightly inflexed, 

 toothless ; the front of the columella rounded, the extremities more 

 or less produced, elongate. 



* Extremities very long. 



1. R. volva, t. 86 a. f. 3. 



** Extremities moderate. 



2. R. spelta, t. 105. f. 6. 



The smaller Radii are found on Gorgonise at the low-water mark 

 of spring tides at Panama. The light- coloured specimens of Radius 

 variabilis are found on cream-coloured Gorgonise, and the purple 

 ones on Gorgonise of the same (purple) colour. — C. B. Adams, I. c. 

 256. 



