31 



California Art & Nature. 



32 



PLANORBIS AMMON Gould. 



Shell large, discoid, subconic, delicately 

 striate; left side broadly and deeply con- 

 cave, showing 4 obtusely carinated 

 whorls; right side concave, showing 2V^ 

 rounded whorls; aperture ovate triangu- 

 lar, sometimes cuite expanded on each 

 side; axis, five-eighths to one; diameter 

 14 to % inch. 



Living: Kiamath lake, Oregon. Honey 

 lake, Lassen county, Calif. Nevada, Colo- 

 rado river. 



Quaternary: Cienega Grande, Colorado 

 Desert.— T. H. Webb; W. P. Blake. La- 

 hontan basin, Lassen county, California. 



PLANORBIS ANITENSIS Cp. 



"Shell (when held mouth downward) 

 with the right side concavo-convex, the 

 left flat (or slightly concave), the left 

 margin forming a sharp car na exi anded 

 beyond the edge of shell, which is marked 

 by a compressed line. Whorls 5, vis b!e 

 on both sides, uniformly flat on the left 

 tide, forming a concave umb 1 cus on the 

 right, where their surfa e is rounde 1. 

 Mouth triangular, the right 1 p arched, 

 the left nearly flat, the extremities joined 

 to outer angle and to obtuse margin of 

 umbiiical cavity. Umbiiicus half as wide 

 as the shell; flat side of mouth one- 

 fourth of diameter; greatest breadth (at 

 mouth) over one-fifth of same; greater 

 ciamete ■ C.'6, least 0.C3 inch."— Cooper, 

 Cal ao pr 2d ser, 3: 341. 



Type locality: Laguna at Santa Anita, 

 Baja California, at an elevation of 100 

 feet, and 10 miles from San Jose del Cabo. 



PLANORBIS BINNEYI Tryon. 

 Living: Oregon; Washington. 



PLANORBIS HORNII Tryon. 



Shell of three convex volutions; aper- 

 ture almost orbicular, not oblque, nor ex- 

 tending above or below the plane of the 

 whorls; labrum slightly reflected, th ck- 

 ened within, its ends converging so as 

 nearly to connect on the parietal wall; 

 lines of growth fine and close. Color 

 light horn. Diameter 21, height 7 mm. 



Livi«g: Fort Simpson, British Ameri- 

 cp. (George H. Horn). Grant's lake, Cal- 

 ifornia (W. M. Gabb). 



PLANORBIS OPERCULARIS Gould. 



Shell dextral, much depressed, lenticu- 

 la.', with a prominent blunted keel at 

 compressed line; tip sunken; beneath 

 the periphery deflned by a marginal, 

 compressed line; tip sunken; beneath 

 umbilicated for about one-third the 

 breadth of the base, showing 3 voiu'ions, 

 convex, surface rather rude and indent- 

 ed, marked with irregular, coarse, much 

 arcuated lines of growth, and here and 

 there a few obscure, raised revolving 

 lines; color dark chestnut brown, a lit- 

 tlfi clord'^d; whorl? above 4, slightly con- 

 vex; suturci well deflned, impressed; ap- 

 erture transversely subrhombic, I'p 

 above slightly declining, at periphery 

 acule-angled, beneath arched, lips em- 

 bracing % of that part of the whorl 



which ig beneath the carina. Diameter 

 C, height 1.5 mm. 



Living: Common In the waters of Cal- 

 ifornia. Vancouver island. 



QUEEN CACTUS. 



