CLASS GASTROPODA 
25 
equal and subequally spaced spiral cords, which divide the space between 
the sutures into four subequal parts. The first of these cords is at the 
summit of the whorl. In addition to the spiral cords, the whorls are 
marked by moderately strong, rounded, vertical axial ribs, of which 12 
occur upon the first, 14 upon the second to fifth, 16 upon the sixth, 18 upon 
the seventh and the penultimate turn. The spiral Cords cross the axial 
ribs as regular bands, their junctions forming elongated rounded tubercles, 
having their long axes parallel with the spiral sculpture, while the spaces 
inclosed between them are well-impressed quadrangular pits with their 
long axes also parallel with the spiral sculpture. On the last whorl very 
faint, intercalated spiral threads appear between the cords. Sutures chan¬ 
neled, showing a faint trace of the subperipheral cord. Periphery of the 
last whorl marked by a rather broad channel, which shows several faint 
spiral lirations. Base moderately long, somewhat concave, ornamented with 
seven subequal and subequally spaced, spiral threads. Aperture irregularly 
oval, channeled anteriorly; posterior angle obtuse; outer lip thin, show¬ 
ing the external sculpture within; columella moderately long, somewhat 
twisted, and reflected. (Bartsch.) 
Type in United States National Museum, No. 14849. Type locality, 
San Diego, California. 
Range. Monterey, California, to San Ignacio, Lower California. 
Bittium quadrifilatum ingens Bartsch, 1907 
Proceedings of the United States National Museum, 33:180. 
Shell similar to B. quadrifilatum, but in every way stronger and larger 
and of a white color. The spiral bands in B. quadrifilatum do not form 
strong cusps at their intersection with the axial ribs, but simple nodes, 
while in the present form these intersections are decidedly cupped. Length, 
12.2; diameter, 4.5 mm. (Bartsch.) 
Type in United States National Museum, No. 32213. Type locality, 
“Albatross” Station 4475, ten miles off Pinos Light, Monterey, California. 
Range. Known only from type locality. 
Bittium armillatum Carpenter, 1864 
Plate 76, fig. 6 
Supplementary Report, British Association for the Advancement of Science, 655. 
Proceedings of the United States National Museum, 40 .391; PI. 52, fig. 6. 
B. testa B. aspero simili; anfr. nucl. ii. laevibus, tumentibus, vertice 
declivi, celato; dein anfr. ix. normalibus planatis, suturis impressis; t. 
adolescente seriebus nodulorum tribus spiralibus extantibus, supra costas 
instructs; costis radiantibus circ. xiii. fere parallelis, seriebus, a suturis 
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