1918.] NATURAL SCIENCES OF PHILADELPHIA. 297 



Alt. 13.3, diam. 22.3 ram.; .5 whorls. 

 " 14 " 23 " scarcely 5 whorls. 

 " 16 " 26.-5 " 5 whorls. 



Santa Catalina Mountains at Station 17, bluffs near Mud Springs, 

 on Pine Canyon. 



The last whorl descends more than in S. marmorarius, the aperture 

 is more oblique, and the color of adults is paler. The immature 

 shells have more of a cinnamon tint than the adults. 



The spiral lines mentioned in the description are usually very 

 faint, often scarcely discernible, but in the largest example they are 

 quite distinct. The umbilicus sometimes varies to somewhat 

 smaller than in the type specimen. 



Mud Springs, on Pine Canyon, a branch of Sabino above Sabino 

 Basin, is a walled hole in the mud. It is on the trail from Sabino 

 Basin to Soldier's Camp, the elevation about 7,000 ft. It is in the 

 pine zone. The Sonorella was found in the first rocks east of the 

 spring along the trail. Also at the foot of a high cliff, in stratified 

 "porphyry," in a ravine heavily wooded with cypress (Cupj'essiis 

 arisonica), about a mile southeast of the springs. 



Sonorella marmorarius imula n. subsp. PI. Ill, figs. 7, "a. 



At Stations 17 and 19 (1917), on a limestone hill 6 miles west of 

 Brush Corral Ranger Station, north of inkier Springs, in the northern 

 foothills of the Catalinas, many specimens were taken, chiefly dead, 

 differing from typical rnarmorarius by the somewhat darker color, 

 and by having about a half of a whorl more in examples of similar 

 diameter. 



Alt. 26.5, diam. 15 mm.; 5| whorls. 



Eighty-five specimens from Station 19, all of the adults collected, 

 measure as follows: 



Diam. in mm 22.3 22.4 22.5 22.6 22.9 23 23.1 23.2 



Number of specimens ...1 1 1 3 1 3 1 3 



Diam. in mm. 23.3 23.4 23.5 23.6 23.7 23.9 24 24.1 



N umber of specimens ...2 3 2 2 3 1 4 2 



Diam. in mm.. 24.2 24.3 24.4 24.5 24.6 24.7 24.8 24.9 



Number of specimens ...6 2 6 4 5 3 2 3 



Diam. in mm 25 25.125.3 25.4 25.5 25.6 25.9 26 



Number of specimens ...4 2 2 22 1 2 1 



Diam. in mm 26.2 26.3 26.4 26.5 



Number of specimens ... 1 1 1 1 



