94 Marine Shells op^ the Western Coast of Florida 



Genus CYRTOPLEUKA Tryon, 1862 



Subgenus SCOBIXOI'HOLAS Grant and Gale, 1931 



Cyrtopleursi"'' oostata (Linne) {Bamca costaia Linne] PI. 19, fig. 124 



Alt. to 95; length to 150 mm. Valves inflated, broadly gaping 

 posterior to middle. Radial ribs, most widely separated over an- 

 terior area, and crossed by strong growth lines, produce a rough, 

 denticulate sculpture. Margins thin, sharp, denticulate. A spoon- 

 shaped apophysis within umbonal cavity. Interior smooth with re- 

 verse pattern of exterior sculpture. 



Colonies of these mollusks live beyond low water mark, in indi- 

 vidual burrows sometimes several feet deep. Burrows are easily 

 identified by the appearance of two large, united, circular siphons 

 at the sand level. 



The common name, angel's wing, is beautifully appropriate to 

 the sculptured, white perfection of this shell. 



Genus BARNEA (Leach MS.) Risso, 1826 



Subgenus AKCHOMASA (Leach MS.) Gray, 1852 



Barnea Iruiu-atai"" (Say) PI. 19, fig. 125 



Alt., 38; length, 60 mm. Shape similar to C. costata, but valves 

 truncate behind. Delicate, slightly denticulate sculpture of fine ribs 

 and growth lines; posterior area almost smooth. Umbonal apophysis 

 narrow and curved. 



The mollusks live in colonies between tide marks and in shallow 

 water, often in the black mud around the mangrove roots. 



Genus ^lARTESIA (Leach) Sowerby, 1824 

 Martfsia cuiieifonnisi"« (Say) PI. 19, fig. 126 



Alt., 11; length, 20 mm. Shell broadly wedge-shape, anterior 

 aspect cordiform; divided into anterior and posterior areas by an 



^^* Gr., cyrtos, curved; pleuron, side; Lat, scobina, file; Gr., pholas, hole- 

 dweller; Lat., casta, rib. 



^•"^ Gr., ankyra, anchor; masa, to chew, to thrust out the lip; Lat., trun- 

 catus, cut off. 



^^^ Lat., cuneus, wedge; forma, form. 



