APPENDIX. 
331 
CATALOGUE—Continued. 
No. 
Name. 
Locality. 
32 
33 
San Diego_ 
Melampus, (undetermined)_._ 
_do_ 
31 
Oliva biplicata, Sowerby_...._ 
San Pedro_ 
35 
P 
- otamis pullatus, Gould. .___ 
San Diego_ _ . . _ 
36 
*Amnicola protea, Gould__ _._, ____ 
Colorado Desert-__ __ __ 
37 
38 
^ Amnicola longinqua, Gould - -- -- -- -- -- -_-_, _ ____ 
®Planorbis ammon, Gould___, „_,_ 
Colorado Desert — Ocoya Creek_ 
39 
c Physa humerosa, Gould_,_ 
Colorado Desert___ 
40 
Succinea, (undetermined)_....___ 
Ocoya Creek__ _____ 
41 
Helix Vancouverensis, Lea..._ 
San Francisco__ 
42 
Helix San Diegoensis, Lea_ 
Point Reyes_ 
43 
Helix infumata, Gould_ 
44 
Helix Oregonensis, Lea_,___ 
Cypress Point__ 
I.—FRESH-WATER SHELLS FROM THE COLORADO DESERT. 
PHYSA HUMEROSA, Gould. 
[Proceed. Bost. Soc. Nat. Hist., V. 128. Feb. 1855.] 
T. solidula, subrhomboidea, polita; spira acuta, anfractibus quinque tabulatis; apertura 
| ad f long ; idtudinis testae adequans, postice obtusa ; labro expanso, columella vix plicata.— 
PI. XI, figures 1, 2, 3, 4, and 5. 
Shell rather large and solid, subrhomboidal, polished; all the specimens seen, (quite numerous, 
and apparently not weathered,) porcelain white. Whorls five, each with a broad, square 
shoulder, and forming an elevated, acute spire ; aperture usually about two-thirds the length 
of the shell, sometimes but little over one-half; posterior angle obtusely rounded; outer lip 
slightly flaring, when viewed in profile it is slightly advanced posteriorly so as to form a recess 
at the junction ; pillar without any conspicuous fold, thickly covered with enamel, broadly 
rounded and expanded at the base. Umbilical region nearly perforate. 
Length of an ordinary specimen, half an inch ; breadth, three-eighths of an inch ; length of 
a variety, seven-tenths of an inch. 
Found in the Colorado Desert, by W. P. Blake ; also at Pecos River, by Dr. T. H. Webb. 
The broadly tabulated whorls, with the acute, elevated spire and foklless pillar, clearly dis¬ 
tinguish this species. P. tabulata, Gould, from New Zealand, is similar, as well as some 
varieties of P. ancittaria, Say, as figured by Haldeman, especially his figure 7, which he desig¬ 
nates as a monstrosity; but the spire is more elevated, and the deep suture always renders the 
whorls distinct, and the absence of a columellar fold is a still further distinctive mark. It 
would be difficult to distinguish the young by themselves from several other species, though they 
begin to show the angularity of the whorls quite early. 
PLANORBIS AMMON, Gould. 
[Proceed. Bost. Soc. Nat. Hist., V. 129. Mar. 1855.] 
T. magna, discoidea, subconica, subtiliter striata; latere sinistro late et profunde concavo, 
