CLASS GASTROPODA 
141 
of the peripheral cord; aperture narrow, simple, anal sulcus feeble, pro¬ 
ducing hardly any appearance of a fasciole; axis nearly pervious, canal 
short, straight. Height of shell, 6.5; of last whorl, 4; diameter, 2.5 mm. 
(Dali.) 
Type in United States National Museum, No. 150993. Type locality, 
Monterey, California. 
Range. Monterey, California, to Cape San Lucas, Lower California. 
Mangilia newcombei Dali, 1919 
Proceedings of the United States National Museum, 56 :71; Pi. 21, fig. 4. 
Shell small, brownish, with a tendency to banding, paler at the shoulder 
and on the base, with six whorls, including a small, smooth nuclear whorl; 
suture distinct, slightly appressed, with no fasciolar constriction; spiral 
sculpture of fine, flattish threads separated by narrow striae very minutely 
reticulated by incremental lines and most conspicuous in the intervals 
between the ribs, practically covering the whole surface of the shell; 
axial sculpture, beside almost microscopic lines of growth, of (on the 
last whorl, 14) short, rounded ribs, slightly angulated at the shoulder 
and extending from the suture to the canal will subequal interspaces; 
anal sulcus shallow, aperture narrow, inner lip erased, canal short, 
straight. Height of shell, 11; of last whorl, 7; diameter, 4 mm. (Dali.) 
Type in United States National Museum, No. 150965. Type locality, 
Clayoquot Sound, Vancouver Island. 
Range. Vancouver Island to Drake's Bay, California. 
Mangilia hecetae Dali and Bartsch, 1910 
Plate 11, fig. 8 
Canadian Geological Survey, Memoranda, No. 1143, 10; PI. 1, fig. 6. 
Shell small, thin, acute-fusiform, externally of a grayish color. 
Whorls about seven, the initial whorl minute and smooth; the second 
bulbous and smooth; the next, finely reticulated by fine spiral threads, 
and somewhat protractive arcuate, fine riblets. This sculpture gradually 
merges into that of the adult whorls; the latter comprise—on the last 
whorl—eleven or twelve arcuate ribs, retractive from the suture, pro- 
tractive from the shoulder of the whorl forward of the canal. These 
ribs are narrow, low, rather rounded, and with interspaces of about twice 
their own width. The whorl slopes in a somewhat excavated manner from 
the suture to the shoulder, where there is a moderate angulation, some¬ 
times forming a rather strong, spiral cord; the rest of the surface is 
covered with very fine, close, even, spiral threading, a little coarser on 
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