LACUNA. 267 



L. UNIFASCIATA, Carp. PL 50, figs. 63 74. 



Small, glossy, generally with a colored keel, the band sometimes 

 broken up into dots. Length, 4 mill. 



California. 

 Var. AURANTIACA, Carp. 



Orange-white, the band and keel obsolete. 



Section MEDORIA (Leach), Gray, 1841. 



L. CRASSIOR, Mtg. PI. 50, fig. 76. 



Stout, solid, opaque, epidermis light yellowish ; whorls convex, 

 a little tumid or round-shouldered above, epidermis thin, often 

 gathered into obliquely longitudinal folds, under it the surface is 

 minutely spirally striate ; pillar lip flattened, expanded; imperfor- 

 ate. Length, 12*5 mill. 



Northern Europe, Greenland, Sitka, 



L. (/I<u"ialis, Moller, and L. pallida, Donovan, are synonyms. 



Section HALOCONCHA, Dall. 1886. 



L. REFLEXA, Dall. PI. 51, fig. 80. 



Thin, light to dark chestnut brown, nearly smooth ; whorls 21-3, 

 rapidly increasing, the last somewhat slantingly flattened above, 

 inflated, suture distinct, umbilicus narrow. 



Length, 10, diam. 13'8 mill. 



Aleutian and Commander Is., Alaska. 



L. ANTARCTICA, Martens. PL 51, figs. 81, 82 ; PI, 46, fig. 34. 



Thin, chitinous, rather widely, excavately umbilicated, thinly, 

 subirregularly longitudinally striulate, with indistinct spiral lines, 

 yellowish brown or chestnut color, umbilical region defined by a 

 decided angle, and depression, interior chestnut color, with a pearly 

 sheen. Diam. 6'8 mill. 



South Georgia, Kerguelen Is. 



L. pumilio, E. A. Smith (fig. 34), is probably the young of this 

 species. 



Section MEGALOMPHALUS, Brusina. 1871. 



L. DEPRESSA, Seguenza. PL 51, fig. 83. 



Minute, whorls rapidly enlarging, the last slantingly inflated, 

 with microscopic, close-set longitudinal folds and intermediate 

 spiral striae, umbilicus wide, its wall flattened, aperture obliquely 

 ovate. Length, 2 mill. 



Algiers, Messina, Britidisi; 11-108 fms. 



