Cardiidae ^ 



one divergent cardinal tooth, one anterior and one posterior lateral 

 tooth. Two oval muscular impressions and simple pallial line. 

 Dredged in five fathoms. 



Family TARDIIDAE 



The Cardiidae are mollusks native to all seas, living in sand at 

 moderate depths. Some genera are strictly marine, others are adapted 

 to brackish water. A long, geniculate foot and two large siphons are 

 prominent characters. 



The shells are equivalve, variable in shape and sculpture, but 

 all are cordiform when observed from either end. All have a perio- 

 stracum, an external ligament, cardinal teeth, simple pallial line, and 

 serrate or crenate margins. 



Genus TRACHYCARDIUM Morch, 1853 

 Trach J cardium»* eg-montianum (Shuttleworth) PI. 12, fig. 71 



Alt., 55; length, 84 mm. Shell subequilateral, light color splotched 

 with brown, thin epidermis; umbos round, approximate; about 30 

 radiating ribs, all bearing short, sharp, semierect, curved processes; 

 cardinal and lateral teeth present; interior smooth, handsomely 

 colored in shades of salmon-pink and purple; margins deeply serrate, 

 interlocking; albino specimens are not uncommon. 



Trachj cardium nmricatura^s (Linne) PI. 12, fig. 72 



Alt., 44; length, 38 mm. Shell with general characters of T. 

 egmontianu7n; yellowish with irregular maculations of brown; about 

 32 ribs, 10 or 12 central ribs almost or quite smooth, others strongly 

 spinose; interior yellow. 



Genus DIIVOCARDIUM Dall, 1900 

 Dinocardium robnstum'"' Yanhyningi Clench and Smith PI. 12, fig. 73 



Alt., 110; length, 82 mm. Shell large, robust, oblique, yellowish 

 brown irregularly maculated with reddish brown; posterior area 

 flattened, dark and polished; umbos rounded, approximate, the op- 

 posed surfaces frequently worn smooth; about 35 strong, flat ribs; 



^* Gr., trachys, rough, rugged; kard'ta, heart. 



^^ Lat., muricatus, from murex, a pointed rock or stone. 



^^ Gr., deinos, huge, mighty; Lat., robustus, hard, strong. 



