248 NUCULID&. 
(Arcacea.) 
Famity NUCULID. 
Shell oval or trigonal, small, nacreous within; hinge composed 
of a great number of transverse teeth, interrupted by a central 
pit for the reception of the ligament, which is internal or external. 
Nucuta, Lam. 
Htym.—Diminutive of nux, a nut. 
Syn.—Polydonta, Muhlf. Nuculites (part), Conrad. 
Distr.—50 sp. Northern and Arctic seas; 10-180 fathoms. 
Siberia, Melville Island, New England, Britain, Mediterranean, 
Cape, Japan, Australia. Fossil,250 sp. (50 Paleozoic, 30 Trias, 
70 Cretaceous, 100 Tertiary.) United States, Europe, South 
India. WN. obliqua, Lam. (cxxvi, 27). 
Shell trigonal, with the umbones turned towards the short 
posterior side; smooth or sculptured, epidermis olive, interior 
pearly margins crenulated; hinge with prominent internal 
cartilage-pit, and a series of sharp teeth on each side; pallial 
line simple. 
Animal with the mantle open, its margins plain; foot-large, 
deeply fissured in front, forming when expanded a disk with 
serrated margins; mouth and lips minute, palpi very large, 
rounded, strongly plaited inside and furnished with a long con- 
voluted appendage; gills small, plume-like, united behind the 
foot to the branchial septum. 
The Nucula uses its foot for burrowing, and Professor Forbes 
has seen it creep up the side of a glass of sea-water. The labial 
appendages protrude from the shell at the same time with the 
foot. 
AcILA, H.and A. Adams, 1858. Valves divaricately sculptured. 
3 recent species. . N. divaricata, Hinds (cxxvi, 28). Fossil. WW. 
ornatissima, d’Orb. (cxxvi, 29). Cretaceous. 
Lepa, Schumacher, 1817. 
Etym.—Leda, in Greek mythology, mother of Castor and 
Pollux. 
Syn.—Lembulus (Leach), Risso. Nuculana, Link. Dacryomya, 
Agass. Jupiteria, Bellardi. Junonia and Saturnia, Seguenza. 
Distr.—80 sp. Northern and Arctic seas; 10-180 fathoms. 
Siberia, Melville Island, New England, Britain, Mediterranean, 
Cape. Japan, Australia, Fossil,190 sp. Silur.—; United States, 
Europe, South India. LZ. pernula, Mull. (exxvi, 31). 
Shell resembling Nucula; oblong, rounded in front, produced 
and pointed behind; margins even; pallial line with a small 
sinus; umbonal area with a linear impression joining the anterior 
adductor. 
