Page:American Seashells (1954).djvu/573

Rh 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.