CLASS GASTROPODA 
39 
Distribution. Chiefly deep-water shells, United States, Britain, Red 
Sea, Greenland, Australia. Fossil: Triassic to Pleistocene. 
Subgenus Bullinella Newton, 1891 
Cylichnella alba Brown, 1827 
Plate 2, fig. 5 
Illustrations of the Conchology of Great Britain, 3; PI. 19, figs. 43, 44. 
Shell subcylindrical, bulging in the center, thin, smooth, glossy and 
white; aperture the whole length of the shell, a little compressed in the 
center, and dilated toward the base; outer lip thin, pillar lip thickened at 
the base, with a very slight duplicature at the bottom of the columella; 
no visible spire, but its apex slightly subumbilicated. Length not quite 
three-eighths of an inch; breadth, an inch and a half. (Brown.) 
Type not known to writer. Type locality, Greenock. 
Range. Arctic Ocean to San Diego, California; circumboreal. Fossil: 
Pleistocene—Santa Barbara, Ventura, San Pedro, San Diego; Pliocene— 
San Diego well. 
Cylichnella nucleola Reeve, 1855 
Last of the Arctic Voyages, 2:393; PI. 32, fig. 2. 
Testa oblongo-cylindracea, medio subcoarctata, laevigata vel striis 
increment aecuatim notata, apice angulato-immersa, sulco latiusculo; 
fulvo-castanea. (Reeve.) 
Of a compressly oblong-cylindrical form, with the spire so impressed 
as to show a broad internal groove, the young shell being coated throughout 
with a dark fulvous-chestnut cuticle. (Reeve.) 
Type in British Museum. Type locality, North of Beechy’s Island, 
Arctic. 
Range. Grantly Harbor, Port Clarence, Bering Strait; circumboreal. 
Described as Bulla nucleola. 
Cylichnella occulta Mighels, 1841 
Proceedings of the Boston Society of Natural History, 1:50. Boston Journal of Nat¬ 
ural History, 4: PI. 14, fig. 11. 
B. testa parva, ovato-cylindracea; spira occulta; labro supra elevato, 
medio recto; apertura sub-angusta, infra lata, rotundata. Length, .2; 
breadth, .15 in. (Mighels.) 
Shell solid, white, covered with a very thin, whitish-yellow epidermis; 
ovate, rather short and swollen, the diameter about two-thirds the altitude. 
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