408 PROCEEDINGS OF THE ACADEMY OF [June; 
Alt. 11, diam. 19 mm.; aperture 9.9 x 11.25 mm. 
17.82 pul Dr at hie ee 
Wee Ase. “""9.9x 41 “ 
sabe ee ie OU IN Be 
‘Mp ae: RATS eRe LS fee an Lhe (ea 
The most closely related species seems to be S. rowelli. This, 
however, has a larger penis-papilla and a slightly wider umbilicus. 
The low and inconspicuous range Las Gijas (the Quartz Hills) 
lies south of the well-known landmark Cerro Colorado, and west of 
the northern end of the Tumacacori Range. At the northwest 
end there is a mine, and aranch building stands on the bank of a 
small stream, the Gija Wash. The hill above the mine is strewn 
with rounded boulders of coarse-grained granite, weathering to 
angular gravel. Most of the loose rock is too massive to move, so 
that suitable situations for snails are scarce. We found the first 
Sonorellas on the slope above the mine. Working up over the 
rounded top of the hill and along the ridge a half mile south we 
crossed a low rock dyke, where a few more shells and a large colubrine 
snake were taken. None were found among the rocks at the head 
of the canyon east of this ridge. The other hills at this end of the 
range are rounded, grassy, with little rock. On top there is much 
sotol, ocotillo, a few cacti, etc. We found the pygmy Agave parvi- 
flora here. It was not seen elsewhere. 
In the débris of the Gija Wash we found Thysanophora hornii 
(Gabb), Zonitoides minuscula (Binn.) and Bifidaria pelleucida hor- 
deacella (Pils.). 
Measurements of the genitalia of the preceding species are here 
given together. The species identified as S. rowelli (Ne.) in these 
Proceepinas for 1905 being added for comparison. 
~ 
= 
S 
= = Sail 
D ne a 5) 2 Es 23 =5 
4 aro ED = mH = Rh 
Bol, a) ee tS | a See 
Age | epee a) ake ea ee Mek me Ses Sys 
a es ee 
S. tumamocensis.......... 10 3.7 | 10 | Trace] 10.7 | 23.5 |- 17.5 |103101 
S. papagorum.............. 6 5 0.5 i 28.5 | 23  /|103099 
SCT ENUILG eee eens 42 DAG a tor are 0 133 en 5) 19 103100 
Y Shi) 251 4 0) 6 20 ie le ee “ 
& A one AO | SO: 3) St | 2s Serge “ 
S. sitiens 6 1 5 | =e A eee 20 103102 
9 ; Gi 1 Baan Rete A, 0 5 25 gl EE: ub 
S. rowelli, Sanfords....) 5 2 5 Trace) “5:3 220 17 83273 
S. rowelli, Patagonia ; 
Wisse eoccnp ae red eR or heverete 0 ASS = eee 15.4 | 83268 
