292 PROCEEDINGS OF THE ACADEMY OF [Nov.—Dec., 
Genitalia (Fig. 4a-d). The penis is slender except at the base 
where it is suddenly dilated. Internally there is a short, sinuous 
fleshy fold and several minor folds in the dilated part of the penis 
where it passes into the atrium, which also contains several fleshy 
ridges. The papilla is long, slender and corrugated. Penial re- 
tractor is terminal and enveloping base of the epiphallus, as usual. 
The epiphallus is nearly as long as penis, with a slight distal swelling 
in place of a flagellum. The vagina is shorter than the penis.. Meas- 
urements of the organs in mm. follow: 
Mir ST Peo Sa. 
Mus. No. Penis. | Papiila. ieee a ee Vagina. | theca | Locality. 
! | | ; E and duct. 
| 
118,045, 10 pace aa 0 6 32 | Sta. 36. 
118,052 | 8.5 6 7.5 minute 4 23 | Sta. 37. 
118,056 9 6.5 7.5 Ss 6 eine 
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The series of 60 specimens from Pima canyon consist chiefly of 
dead shells. The average size appears to be slightly less in the 
specimens from the western side of the canyon, forming the eastern 
slope of Pusch Ridge. 
There are three ‘‘dead’”’ specimens from ‘‘Pusa Ridge” (? = Pusch 
Ridge) in the U. S. National Museum, No. 271,011, collected by 
Barber. The diameter is about 22 mm. 
The specimens from the canyon north of Romero (opening north- 
westward), Station 45 (1917), have the same range of variation 
noted in Sabino canyon S. sabinoensis. There are depressed, more 
openly umbilicate shells, together with smaller, usually less depressed 
shells with relatively larger aperture and smaller umbilicus, 3 to 
4 covered by the expansion of the columellar lip; also a few specimens 
transitional in these characters. 14 examined. 
Alt. 15.4, diam. 27.3 mm., 42 whorls (largest). 
6c 15.6, 6c 93 ‘c 4s “c 
eee CS Ged) ce” a ce (smallest). 
The genitalia do not differ from Pima canyon shells. 
Seven shells from Station 43 (1917) measure: diam. 21, 21.5, 
23.5, 23.7, 24, 24.4, 24.4 mm. 
All of the localities for this form are in the arid lower zone of the 
range. 
Sonorella sabinoensis buehmanensis n. subsp. PI. V, figs. 2 to 3b. 
Typically the shell differs from S. sabinoensis by being more solid 
and more elevated, only very slightly paler near the shoulder band, 
and with nearly one whorl more in examples of the same diameter. 
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