GASTROPODA— PURPURIDJE. 



7*7 



584. T. tetricus Conrad. (Fig. 11 50, c, d.) Miocenic. 



With 9-12 varices which are sharp and end at the shoulder angle 

 in compressed open spines ; canal long and straight. 



Chesapeakean of Atlantic coast. 



Family Purpurid^h: Gray. 

 CLXXXI. Ecphora Conrad. 

 Large, short and thick shells, rather loosely coiled towards the 

 last, leaving a wide umbilicus. Aperture more or less pyriform, 

 extended into a short anterior canal. Surface marked by coarse 

 spiral folds, rarely by finer spirals. Miocenic. 

 585. E. quadricostata (Say). (Fig. 1151.) Miocenic. 



Fig. 1 151. #, Ecphora quadricosiata, X %'■> &, var. umbilicata, X Z A > c > voun g> 



X 2. (Md. Survey.) 



Adult shell deeply umbilicated, with four very prominent, pro- 

 jecting spiral folds, often T-shaped in section, less prominent and 

 somewhat noded in the young. Variety umbilicata (Fig. 1151, b) 

 has a larger umbilicus, looser coil, thinner, not T-shaped spirals. 

 E. tricostata (Fig. 1152, b) has the lower spiral weak or absent. 



Chesapeakean formation of Maryland and Virginia. 

 586. E. tampaensis (Dall). (Fig. 11 52, a.) Miocenic. 



Resembles the young of E. quadricostata; spiral folds moderate, 

 numerous on anterior portion, on main part of whorl with finer 

 intercalated ones ; growth lines lamellose between spirals. 



Silex beds of Florida; Chesapeake beds of Maryland. 



