SOLENID^ 1*33 



seen in species of Tagelus. Externally the tjqie species resem- 

 bles the recent Pharella Javanica. 



SiLiQUA, Muhlfeldt, 1811. 



Syn. — Leguminaria, Schum., 1817. Machaera, Gld., 1841. 

 Aulus, Oken., 1815. 



Distr. — 20 sp. India, China, Ochotsk, Oregon, Sitka, Behr- 

 ing's Sea, Newfoundland, Atlantic United States. M. costata, 

 Say, is often obtained from the maw of cod-fish. Fossil, 4 sp. 

 Upper Greensand — ; Britain, France. S. radiata, Linn, (cvi, 13). 



Shell smooth, oblong ; epidermis polished ; an umbonal rib 

 extending across the interior of the valve ; pallial sinus short. 



The animal is similar to Solecurtus. 



Prothyris, Meek, 1869. 

 Distr.—2 sp. Garb. ; U. S. P. Meeki, Winchell (cv, 90), 

 Shell equi valve, very inequilateral, longitudinally oblong ; 

 valves compressed or moderately convex ; nearly closed or a 

 little gaping behind, and more or less widely gaping in front, 

 where the hiatus is increased in size by a nearly rectangular 

 notch in the margin, mainly below the middle ; beaks depressed 

 and very near the anterior end, with a small ridge usually 

 extending from the anterior side of each to the corner of the 

 anterior marginal notch ; dorsal margin without escutcheon or 

 lunule, being erect and sharp behind the beak ; surface merely 

 marked with striae of growth. Hinge and interior unknown. 



Solecurtus, Blainv., 1824. 



Syn, — Solenocurtus, Sowb., 1839. Tagelus, Gray, 184*7. Sili- 

 quaria, Schum., 1817. 



Distr. — 11 sp. E. and W. Coasts of N. and S. America, Sene- 

 gal, Mediterranean. Fossil, 30 sp. Neocomian — ; United 

 States, Europe. S. Dombei,^ Lam. i cv, 87). 



Shell elongated, rather ventricose, with subcentral beaks ; mar- 

 gins subparallel ; ends truncated, gaping; ligament prominent; 

 hinge-teeth two in each valve ; pallial sinus very deep, rounded ; 

 posterior adductor rounded. 



Animal very large and thick, not entirely retractile within the 

 shell ; mantle closed below ; pedal orifice and foot large ; palpi 

 triangular, narrow, lamellated inside ; gills long and narrow, 

 outer much the shortest ; siphons separate at the ends, united 

 and forming a thick mass at their bases ; anal orifices plain, 

 branchial fringed. 



The Solecurti bury deeply in sand or mud, usually beyond 

 low-water, and are difl^cult to obtain alive. P. Caribaeus occurs 

 in countless myriads in the bars of American rivers, and on the 

 coast of New Jersey in sand exposed at low-water ; by removing 

 three or four inches of sand its burrows may be discovered ; 



