1:0175 Arcularia " erebristriata, Opn, 1857. Mazatlan; Salina 
z _ Cruz. ‘ 
jo. 
:0177 Arcularia major Stearns, 1984. 
is parently quite distinct from complanata, of which it Dae be a 
_ geographical race, like the next species. 
— 21:°0178 Arcularia iodes Dall. Guif of Cal. 
He 1:0179 Arcularia scabriuscula Powys, 1835. Central America. 
a -Synonymy:—Nassa stimpsoniana C; B.. AG, 1852. 
1:0180 Arcularia exilis Powys, 1835. Panama: Chile. 
. Synonymy:—Nassa fontainei Orb., 1841, and panamansis 
meni. 1851, non C..-B: Ads. 1852, 
. 
% 
ar 
- 21:0181 ILYANASSA Stimpson. 
ie Shell dark olive brown, reticulated, outer lip without varix, 
_ striate within, columella covered with a spreading callus; oper- 
— culum with entire margin; animal with broad foot, not bifurcated. 
I: obsoleta has been introduced from the Atlantic to San Fran- 
me cisco bay, Cal: M2560. 
~ 21:0182 PHOS Montfort, 1810. 
Tae Shell cancellated, oblong, acuminated, usually longitudin- 
- ally ribbed; outer lip striated internaliy, with a light sinus near 
i _ the fore part; columella obliquely grooved, or with a single plait 
= in front; operculum claw-shaped, nucleus apical. 
81: 0183 Phos cocesensis Dall, 1896. Cocos Island. 
D3 4. 0184 Phos crassus Hinds, i844. Baja Cal.; Gulf Cal. 
ri " 21:0185 Phos chelonia Dall. Galapagos Islands. 
~ 21:0186 Phos alternatus Dall. Gulf of Cal. 
- 21:0187 Phos mexicanus Dall. Cape San Lucas; Panama. 
_ 21:0188 Phos minusculus Dall. Panama Bay. 
_ 21:0189 NASSARINA Dall, 1889. 
_ 21:0190 Nassarina solida Dall. Near La Paz. 
- 21:0191 HINDSIA Adams, 1853. 
' 21:0192 Hindsia perideris Dall, 1910. Near La Paz. 
% " 21:0193 Northia northiae Gray, 1833. Gulf Cal. south. 
. 21:0195 GOULDIA C. B. Adams, 1847. . 
- 21:0196 Gouldia californica Dall. Near La Paz. wn 
o 
~~ 21:0197 PERIPLOMA Schumacher, 1817. 
_ deepest; posterior side very short and contracted; hinge with a 
narrow, obliquie, spcon-shaped process in each valve, and a small 
triangular ossicle; an internal rib proceeds from under the hinge 
to the posterior margin; muscular impressions unequal, the an- 
terior long and narrow, the posterior small, semilunar; pallial 
impression marginal; siphons iong, slender, separate. 
176 Arcularia complanata Powys, 1835. Panama; Valpariso. 
Gulf of California to Panama. Larger, yellow-brown, ap- 
Shell oval, very inequilateral, slightly nacreous; left valve 
