CUSPIDARIIDAE 475 



entire surface of the valve. Uncommon, lo to loo fathoms, from North 

 Carohna to the West Indies. Called Fischer's Verticord. 



Family POROMYIDAE 

 Genus Poromya Forbes 1844 



Shell small, fragile; sculpture of fine granules in radial series. Hinge 

 of right valve with a strong cardinal tooth in front of a wide chondrophore; 

 hinge of left valve with a small cardinal tooth behind and above the chondro- 

 phore. 



Poromya granulata Nyst Granular Poromya 



Plate 30s 



Cape Cod, Massachusetts, to east Florida and Cuba. 



y4 to Ys inch in length, ovate, inflated and fragile. Beaks inflated and 

 turned forward. Exterior cream-white, with an irregular coating of fine 

 granules which resemble sugar-coating. In fresh material, this granular 

 deposit is also found on the inner margins of the valves. Slightly gaping 

 at the posterior end. Interior of valves silvery white. Commonly dredged 

 in a few fathoms of water off eastern Florida. 



Poromya rostrata Rehder (Cape Hatteras, North Carolina, to east Flor- 

 ida and the West Indies, 60 to 100 fathoms) is distinctly rostrate posteriorly 

 and the granules are larger, more evenly spaced and generally cover the en- 

 tire outer shell. It is relatively uncommon. 



Family CUSPIDARIIDAE 

 Genus Cuspidaria Nardo 1840 



Shell small, globose in front, rostrate behind. Hinge with a posterior 

 lateral tooth in the right valve. External ligament elongated. Resilium in a 

 small, spoon-shaped fossette. Lithodesma distinct and semi-circular. 



Cuspidaria glacialis Sars Glacial Cuspidaria 



Figure 97b 



Nova Scotia to Maryland. Gulf of Mexico? Alaska. 



I to I % inches in length, rostrum moderately long and compressed lat- 

 erally. Main part of valves fat and round. Sculpture consists of small, irreg- 

 ular growth lines. Periostracum grayish white. Shell cream to white. A 

 common species dredged from 64 to over 1400 fathoms. C. Jeffrey si in the 

 south is very similar, but smaller, with a rostrum* which in cross-section is 

 much more oval and less compressed, and with hardly any periostracum. 



