CLASS GASTROPODA 
147 
Acmaea cassis olympica Dali, 1914 
Plate 94, figs. 12, 13 
Nautilus, 28:14. Tryon and Pilsbry, Manual of Conchology, 13: PI. 8, figs. 92-94. 
Shell small, conical, elevated, having much the shape of A. mitra. The 
color outside is gray, pink, or light purple, painted with a few or many 
black stripes. A dark spot is inside. Ribs obsolete. Length, 25-30 mm. 
(Tfyon and Pilsbry, Manual of Conchology.) 
Type in United States National Museum. Type locality, Olympia, 
Washington. 
Range. Alaska Peninsula to San Diego, California. 
t 
Acmaea cassis nacelloides Dali, 1871 
Plate 94, figs. 7, 8, 9 
American Journal of Conchology, 6:247; PI. 17, figs. 36, a-c. 
A very distinct variety of this species ( Collisella pelta Es-ch.) has 
exactly the aspect of Nacella instabilis externally. It is of a blackish- 
brown, with sharp, radiating grooves sometimes obsolete near the apex. 
.Several shells beginning in this way have a margin with the normal char¬ 
acters of C. pelta. It is quite distinct from the variety monticola Nutt., as 
described by Dr. Carpenter in the American Journal of Conchology, 2:33, 
and might readily be taken for a distinct species, as the sculpture differs 
entirely from that of the normal pelta, which is sparsely furnished with 
prominent bulging ribs. (Dali.) 
Type in United States National Museum. Type locality, California. 
Range. Attu Island, Aleutian, to San Diego, California. 
Described as Collisella pelta nacelloides. 
Acmaea scutum Eschscholtz, 1833 
Plate 85, figs. 12, 17 
Zoological Atlas, pt. 5, 19: PI. 23, figs. 1-3. 
A. scutum. Testa ovato-oblonga convexa, transversim striata, extus oli- 
vacea, lineis flavescentibus radiantibus inaequalibus picta, intus livida, 
macula sub fornice fusca spathulaeformi magna, vertice subcentrali ob- 
tusissimo, margine crenato. 
Der Gipfel ist etwas abgerieben. Um ihn herum befindet sich ein 
braunlicher, verwischter Saum, an dem iibrigen Theile ist die Grundfarbe 
ein schmutziges Olivengriin, das gegen den Rand ins Schwarze iibergeht. 
Viele gelblich weisse verschiedentlich lange, im Ganzen aber nur kurze 
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