92 MOLLUSCA FROM THE CRAG. 
ligamental pit, somewhat contracted in the middle ; a large lanceolate-formed and well 
defined lunule and corslet may be seen on both sides of the umbo, but the muscle 
marks within are very slightly impressed and are indistinct, with doubtful traces of a 
deeply sinuated form in the one by the mantle. 
I am not at all acquainted with the range of this species; but it does not appear 
to have a specific relationship with Mucula levis, Say, with which M. Nyst has con- 
sidered his shell identical, and to which he would also unite JV. limatula, a very 
different species. It resembles in outline JV. sapotilla, Gould, but seems to differ speci- 
fically from it in the conspicuous transverse ridges, as well as in having a greater 
number of teeth, depending upon the figure and description of that very accurate 
observer, Dr. Gould, who would undoubtedly have poimted out the exterior ornament 
had it possessed any. 
4. Lepa caupata, Donovan. Tab. X, fig. 12, a—é. 
Arca caupaTa. Don. Brit. Shells, vol. ii, pl. 78, 1802. 
— minuta. Mont. Test. Brit., p. 140, 1803, not Broc. 
_ — Turt. Conch. Dict., p. 11, fig. 98, 1819. 
— — W. Wood. Ind. Test., p. 47, pl. 10, fig. 44, 1828. 
Nucuta minuTa. Turt. Brit. Biv., p. 178, 1822. 
_ o Brown. Ulust. Conch. Gr. Brit., pl. 25, fig. 18, 1827. 
— — S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 298, pl. 14, fig. 6, 
1840. 
a — Gould. Invert. Massach., p. 101, 1841. 
—  rosrrata. G. Sowerby. Genera No. 17, fig. 5. 
— Mac Gill. Moll. Aberd., p. 245, 1843. 
Lepa minuta. Mller. Ind. Moll. Groenl., p. 17, 1842. 
— a King. Aun. Nat. Hist., vol. xviii, p. 240. 
oa a Forbes. Mem. Geol. Sury., vol. i, p. 419, 1846. 
— caupata. Lovén. Ind. Moll. Scand., p. 34, 1846. 
— —_ Alder. Cat. Moll. North. and Durh., p. 79, 1848. 
_ — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 226, pl. 47, figs. 12, 13, and 
pl. P, fig. 2, 1849. 
Spee. Char. Testa traxsversd, elongato-ovatd, vel ficiformi, conveviusculd, tenui ; con- 
centrice striata, antice breviort, rotundatd ; posticé longiort attenuata, angulatd, et sub- 
rostrata, margine integro. 
Shell transverse, elongato-ovate or fig-shaped, slightly convex, thin; covered 
with transverse or concentric striae; anterior side the shorter, rounded, posterior 
attenuated, angulated, and subrostrated, margin smooth. 
Longitudinal diameter, 5 an inch nearly. 
Locality. Red Crag, Sutton. 
Mam. Crag, Bridlington. 
Clyde Beds. Recent, Britain, Scandinavian Seas, and North America. 
