- 39 The West American Scientist. 4G 
Pee OPERCULARIS Gould PLANORBIS TUMIDUS Pfeiffer. 
Shell dextral, much depressed, featicn. hell opasue, pale horn color smo 
la>, wi a Drominent blu keel at ky, densely and finely striated, umbili 
compressed line; tip sunken; neath cated above, slightly concave below; 
the periphery defined by a rginal, whorls 5, convex, subcarinated on each 
compressed line; tip sunken; beneath side, ra idly increasing, separated by a 
umbilicated for about one-t the deep suture; aperture oblique, bowie 
adth of the base, showing 3 volutions, rounded, somewhat kidney-shaped. Di- 
convex, oe wire rather rude and indent- ameter 19, gab 
ec, mar with irregular, coarse, mu ivine: oe Los "Angeles, Califor- 
ose Tbibe of growth, and here and nia. Nica agua woo Brydges). Guatema- 
ther few eoure. raised revolvi 
: color dark chestnut brown, a lit- pLANORBIS VERMICULARIS Gould. 
tle clouded; whorls above 4, slightly .con- Shell dome-sha ped, minu 
u 
part of the whorl 
h is eg mane the carina. Diam 
ht 1.5 
Con mon in the waters of Cal- 
“hlaigihbed island. 
BIS PARVUS Say. 
“3 All British America oi babs ety 
Manitoba to New Mex 
filles canyo n, Baja. California eoreeity 
meter. Mouth tranezoid- 
e, its lips curve e the right 
attached ne concave 
obtuse pesphes ry of 
h one- third longer than wide; 
hird that o 
Cal. 
n 
i —Coo oper, 
Tyre tocaitiy: “With P. anitensis, 
: aguna 
oP isk. Reokpia SU ECRENATUS S Cpr. 
~ t thin, horn-colored: 
sutures impressed: 
be 
whorl: 
cous within; 
22 ne eig 
ng: <iens on hla rate 
lonibia to 
British Co- 
© Baja Californi 
iving: azatla Baja Californ‘a; 
San Francisco, Petaluma, and south m 
California. 
by growth, wh 
height of the last whorl and 40 by 
allus, Hei 1.6, diameter 5 mm. 
Living: regon; California; Baja Cal- 
ifornia (Orcutt). 
POMPHOLYX EFFUS 
HO 
Shell roundly gibbous, meg thin, ef- 
oye reddish horn- colored be greenish, 
orls: 5, flattened above, concave below = 
Reriisee subro tund, dilated, ew hite with- 
in. Leng 
03. 
t oc ‘count to 
Lake Takes Califor ee " Btanla lake, 
White Pine, Nevada (Henry Hemphill). 
Beg S ecrigthoan Dall. 
iving: xin, Springs, Owens river val- 
ley, Califor 
TRYONIA CLATHRATA pcs gg ae 
Shell elonzated, narrow; a i ‘spire 
acute; sutures deeply i congad: whorls 
%, with generally about 12 longitudinal 
ribs crossing , SO es crossed by 
revolvinz ee e r ridges, and angulated 
oe ap mic aperture rounded oval, 
la ake, Colorado Des- 
perture 
ndeéd posteriorly; lip 
incrusting the i 
D 
region 
ength one-eighth, breadth one-tenth 
: Utah.—Henry Hem phil 
Quaternary: ee Grands. © iced 
Desert.—W. P. Blake. Lahontan basin, 
Lassen county, Calif., Nevada. 
VALVATA VIRENS 
Sides turbiniform, of 
orls: spire e'evated 
renee decniy in 
angulated; 
Tryon. 
well- op 
t 
2 
Sur- 
Color brilliant ta 
Height 5, @ameter 
Clear lake, California. 
