1923] NATURAL SCIENCES OF PHILADELPHIA 
Or 
or 
Thysanophora horn (Gabb). Stations 53, 62, 87, 89. 
Gonyodiscus cronkhite: (Ne.) Tumamoc Hill. 
Helicodiscus arizonensis P. & F. Station 53. 
Pupoides marginatus (Say). Stations 65, 82. 
Chaenaxis tuba (Pils.). Stations 53, 62, 82. 
Chaenaxis intuscoslata (Clapp). Stations 87, 89. 
Gastrocopta bilamellata (St. & Clapp). Stations 82, 87. 
We have not succeeded in tracing Sonorella arizonensis Dall, 
based on a unique bleached shell found in the Santa Cruz River, 
Tucson. 
SIERRITAS AND SILVER BELL RANGE west TO Ajo yielded the 
following species: 
Sonorella ambigua P. & F. Coyotes and Robles Hills to 101 
miles west of Tucson. Nariz Mts. on the Mexican Boundary. 
Sonorella xanthenes P. & F. Kitt’s Peak. 
Sonorella baboquivariensis depressa P. & F. Sierritas, Baboqui- 
varis. 
Sonorella berryi P. & F. Station 103, Roskruge Mts. 
Sonorella sitiens comobabiensis P. & F. Cababi Mts., near 
Indian Oasis, south end Quijotoa Mts. 
Sonorella tumamocensis var. Silver Bell Mts., Station 46; 
Roskruges, Station 110. 
Thysanophora hornii (Gabb). Station 136, Quijotoas, and 132, 
Covered Wells. 
Pupoides marginatus (Say). Station 128, Wall’s Wells, Ajo 
Range; 132, Covered Wells. 
Chenaxis intuscostata (Clapp). Station 136, Quijotoa Range. 
Chenazis tuba (Pils.). Station 92, Robles Hills. 
Gastrocopta pellucida hordeacella (Pils.). Station 128, Wall’s 
Wells, Ajo Range. 
Gastrocopta bilamellata (S. & C.). Station 128, Wall’s Wells, 
- Ajo Range; 132, Covered Wells. 
Gastrocopta perversa (St.). Station 203, south side Sierritas. 
Gastrocopta ashmuni (St.). Station 203, south side Sierritas. 
Succinea avara Say. Station 128, Wall’s Wells, Ajo Range, and 
Station 131, plain between Ajo and Quijotoa Mts. 
II. List or SraTions AND oF MoLLUSKS COLLECTED IN THE 
Empire, WHETSTONE, Mustane, Huacnuca, Sanra Riva, Pat- 
AGONIA, SAN CaYENTO, TUMACACORI AND PagariTos RaNGEs. 
A general account of the winter and spring campaign of 1919, 
by one of us (J. H. F.), may be found in The Nautilus, XX XIII, 
pp. 37-44. Descriptions of some of the species taken are given 
in the same volume, pp. 19-21. 
