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394 Genus Echinochama P. Fischer 1887 Echinochmna cornuta Conrad Florida Spiny Jewel Box Plate 37g North Carolina to both sides of Florida to Texas. I to I % inches in length, quadrate in outHne and rather obese and heavy. Lunule distinct and broadly heart-shaped. With 7 to 9 rows of moderately long, stoutish spines, between which the shell is grossly pitted. Exterior creamy-white; interior white or flushed with bright pinkish mauve. Attached to a small pebble or broken shell by the right valve. Common from 3 to 40 fathoms, and commonly washed ashore. Echinochama arcinella Linne (True Spiny Jewel Box, pi. 37h) from the West Indies to Brazil has 16 to 35 (commonly 20) radial rows of slender spines. The shell is not as obese nor as heavy as cornuta. The subspecies calif orjiica Dall (pi. 37e) is very similar, with slightly longer spines and with a more compressed shell. It ranges from the Gulf of CaHfornia to Panama in offshore water. Superfamily LEPTONACEA Family LEPTONIDAE A group of small, fragile, inflated, translucent clams which are parasitic or commensal on other marine creatures or are active crawlers like the gastro- pods. Most species brood their young inside the mantle cavity. The family is also named Erycinidae and Kelliidae. Genus Kellia Turton 1822 Shell unsculptured, inflated and oval-oblong. Lateral teeth present. 2 cardinal teeth in the right valve. Kellia laperousi Deshayes La Perouse's Lepton Alaska to Panama. % to I inch in length, oval-oblong, rather obese and with small beaks near the center. Shell fairly strong, chalk-white, but commonly covered with a smooth, glossy, greenish to yellowish-brown periostracum which, however, is commonly worn away in the beak area. Very common. Found attached to wharf pilings among mussels and chama shells. Genus Lasaea Brown 1827 Shell very small, beaks nearer one end. Teeth the same as in Kellia.