1917.] NATURAL SCIENCES OF PHILADELPHIA. 97 



Oreohelix metcalfei concentrica n. subsp. PI. VIII, figs. 1-ld. 



The shell is much more broadly and openly miibilicate than 

 0. tnetcalfei; cartridge buff, inconspicuously mottled with gray or 

 light drab, the embryonic whorls pinkish cinnamon, and the peripheral 

 keel bordered below with a bro\\'n band. Sculpture of about five 

 extremely low spiral cords on the base, and usually traces of two or 

 three above, their intervals finely and sharply striate spirally, and 

 there are very fine, irregular striae along growth-lines, sharp where they 

 pass over the keel and spiral cords, elsewhere weak. The last whorl 

 does not descend in front. 



Alt. 9.3, diam. 21.5 mm.; 4| whorls. 



Silver Creek, above 7,500 feet, at stations 3, 4|, 7, and 11, on 

 limestone outcrops. Type No. 115,755, A. N. S. P. from Station 7, 

 above the box of Silver Creek, on the north side. 



In most specimens the intervals between the cords on the base are 

 dull brown, or when concolored the spiral striae make them appear 

 darker, giving an appearance of relief to the cords. A few individuals 

 from Station 11 (a branch ravine of Silver Creek south of Gray's 

 cabin) have the base blackish chocolate. 



Specimens with the spiral cords on the base less conspicuous and 

 the color usually darker — clouded and banded with dull walnut 

 brown in varying degree — were found at Station 20, at the Grand 

 Central Mine; Station 19, the next gulch north of that where the 

 mine is; also Station 22, the succeeding gulch north (PI. YIII, fig. Id). 

 At Station 17|, on the west side of Sawyer Peak about 500 feet below 

 the summit, similar shells were found, varying from nearly typical 

 color to broadly banded below with chocolate, the spiral cords 

 therefore inconspicuous. 



Genitalia as in 0. m. radiata. 



The embryonic shell (PI. IX, fig. 10) is very beautiful. The 

 first whorl is smooth, cuticular laminae along growth-lines then 

 appearing gradually. From these triangular processes rise, forming 

 3 or 4 spiral series above, usually 4 below a peripheral series of larger 

 processes. 



The embryos of radiata, acididiscus and hermosensis are identical 

 with those of concentrica. 



Oreohelix metcalfei radiata n- subsp. PI. VIII, figs. 2, 2a, 3-3c, 6, 6o. 



The shell is more openly umbilicate than 0. metcalfei, with irregular 

 sculpture of strong wrinkles in the direction of growth-lines, the lens 

 •showing fine spiral striae between the wrinkles of the lower surface, 

 very few on the upper surface. Faint traces of a few coarse spirals 



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