244 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Type in British Museum. Type locality, Panama. 
Range. San Pedro and San Diego, California, to Panama. 
Described as Triton gibbosns . 
Family SEGUENZIIDAE 
Genus SEGUENZIA Jeffreys, 1876 
Shell globular or conical, glossy, without epidermis, exquisitely sculp¬ 
tured; upper part of the last whorl deeply and widely grooved; pillar 
abruptly notched below, and exhibiting a small tooth-like process; base 
either deeply umbilicated or imperforate. 
Differs from the other genera by having a broad sutural slit, instead of 
on the periphery. Operculum very thin, paucispiral. (Tryon, Structural 
and Systematic Conchology .) 
Type. Seguenzia formosa Jeffreys. 
Distribution. Azores, West Indies, Pernambuco, California. 
Seguenzia caliana Dali, 1919 
Plate 33, figs. 4, 5, 6 
Proceedings of the United States National Museum, 56:344. 
Shell small, white, elevated, trochiform, with a minute, glassy, smooth 
nucleus, and about five subsequent whorls; suture obscure, laid on the 
peripheral keel; spiral sculpture of, on the spire, a single sharp prominent 
keel somewhat behind the central line between the sutures, and, on the last 
whorl, a similar peripheral keel with a wide excavated space on each side 
of it, the space behind the periphery wider; base with seven, rather close- 
set, squarish cords, those nearer the axis most adjacent to each other; 
axial sculpture of low, thin, sharp lamellae with wider interspaces over¬ 
riding the peripheral keel on the spire but not on the last whorl, prominent 
in the interspaces behind the base, retractively arcuate in the posterior 
interspace, and protractively arcuate in the others; they do not invade the 
somewhat flattish base; aperture with a very deep sulcus next the suture, 
the outer lip in front of it much produced; a feeble sulcus at the middle of 
the base; in front of the arcuate pillar a smaller rounded dentation; behind 
the pillar a deep groove ending in a minutely perforate umbilicus; body 
with no perceptible glaze. Height of shell, 4.5; diameter, 3.2 mm. (Dali.) 
Type in United States National Museum, No. 207694. Type locality, 
U. S. Fish Commission Station 2928, off San Diego, California, in 417 
fathoms. 
Range. Off La Jolla and San Diego, California. 
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