68 



EAST COAST MARINE SHELLS 



ligament long and well developed. 



GENUS SAXICAVA Fleuriau de Bellvue 1802 

 (STONE BORER) 



SAXICAVA ARCTICA Linn§. Arctic Stone Bor- 

 er. An excessively variable shell, con- 

 forming to its place of attachment; ros- 

 trate in front; diagonal ridge spinous. 

 Length 1 inch. 



Often fastened by a silk-like bys- 

 sus coming from inside of base. Foot of 

 animal bright orange color. Range 1-100 

 fathoms. 



PI. 10, Fig. 11 

 Greenland to West Indies 



SAXICAVA AZAREA Dall. Length 1 inch. 

 Range 13-14 fathoms. 



PI. 62, Figs. 9a, 9b 



Charlotte Harbor, Florida to Texas 



GENUS PANOPE Menard 1807 



PANOPE BITRUNCATA Conrad. Oblong Panope. 

 Shell short, contracted, obliquely cut off 

 at anterior end; small cardinal tooth in 

 right valve; compressed and flattened on 

 posterior end; palllal sinus widely and 

 bluntly rounded. Length 5.25 inches; 

 width 3 incnes. 



The individuals living in easily 

 movable material such as sand or fine mud 

 are thinner, longer, less distorted than 

 those associated with gravel. 



P. floridana Dall, a Pliocene fos- 

 sil frequent in Florida, is identical. One 

 of the fossil shells is represented in the 

 present illustration. 



PI. 4, Fig. 5 



North Carolina to Mobile Point, 



Mississippi 



GENUS PANOMYA Gray 1857 



Shell equivalve, gaping unequally 

 at base and sides; a small upright tooth 

 in each valve. 



PANOMYA ARCTICA Lamarck. Shell strong, 

 both ends gaping; anterior end rounded, 

 other end truncated; three wave-like ridg- 

 es cutting surface into three equal por- 

 tions; covered with a thick, dusty, wrin- 

 kled epidermis. Length 2.5 inches. 



This species is plentiful in tlie 



fossil beds of Europe and America but is 

 rather rare in the living state. It inhab- 

 its the Banks of Newfoundland and the Arc- 

 tic Seas of Europe. Range 25-115 fathoms. 



PI. 26, Fig. 1 



Arctic Ocean to Georges Bank 



Family Gastrochaenidae 



GENUS GASTROCHAENA Spengler 1783 



Shell equivalve, widely gaping, 

 umbones at anterior end; concentric sculp- 

 ture faint and forming flask-shaped bur- 

 rows (mostly in corals and shells) lined 

 with calcareous material or forming a tube, 

 when burrow is absent, to which the ex- 

 traneous matter is fastened. 



GASTROCHAENA CUNEIFORMIS Spengler. The 

 giant hiatus, nearly as long as the shell, 

 separates this form, also the blunt and 

 wide extremity of the valves. Length 23 mm. 



PI. 14, Fig. 7 



North Carolina to West Indies 



GASTROCHAENA OVATA Sowerby. A narrower 

 shell than the preceding; Interior of each 

 valve with a long sharp projecting ridge 

 which is placed in the middle; concentric 

 sculpture closely set and irregularly ar- 

 ranged. Length 30 mm. 



The shell of Spondylus is a favor- 

 ite host for these mollusks which have been 

 found abundant in the Gulf of Mexico. 



PI. 14, Fig. 6 



South Carolina to West Indies 



Family Pholadidae 



Shell gaping at both ends and with 

 teeth-like sculpture in front; no ligament 

 or hinge; sometimes reinforced with addi- 

 tional valves. 



GENUS PHOLAS Linn6 1758 

 (ANGEL WINGS) 



Hinge margin rolled out and tooth- 

 less; tooth emerging from beak cavity very 

 prominent. 



PHOLAS CAMPECHIENSIS Gmelin. Campeche 

 Wing. Shell elongated, open anteriorly, 

 rayed all over with rounded rather dis- 

 tinct ribs; two accessory valves covering 



