146 



American Seashells 



with a septum. As additional growth takes place, the animal retreats grad- 

 ually from the apical or rear portion and forms new, internal septa. The 

 operculum is thin, circular, homy, and multispiral. 



Figure 37. American Caecums. ATLANTIC: a, Caecum florida?m?n Stimpson; 

 b, C. cooperi S. Smith; e, C. carolinianum Dall; d, C. piilchellwn Stimpson; e, 

 C. nitidum Stimpson; f, C. nebulosum Rehder (type). PACIFIC: g, C. californicum 

 Dall; h, C. dalli Bartsch (type); 1, C. carpenteri Bartsch (type); j, C. occidentale 

 Bartsch (type); k, C. heptago?nmi Cpr.; I, C. orciitti Dall (type); m, C. crehricbic- 



tinn Cpr. All Xio. 



I 



Genus Caecum Fleming 18 17 

 Subgenus Caecum s. str. 



Caecum floridanum Stimpson 



North Carolina to Southern Florida. 



Florida Caecum 



Figure 37a 



