PROCEEDINGS OF THE NATIONAL MUSEUM 



vou 76 



carina at the aperture. Shell flesh color, nearly white, a brown spiral 

 band just above the carina and one below it. 



The type and 14 paratypes come from the Canyon atSupai, Coco- 

 nino County, Ariz., and were collected and presented by Mrs. 

 Charles D. Walcott, whose maiden name has been bestowed upon it. 



The dimensions of the type and of those of the paratypes which 

 are adult are as follows, in millimeters : 



The prominent characteristics of this shell are the depressed conic 

 spire, the plump round base, the cordlike white carina, the granulated 

 striae, the wide umbilicus, and the two brown bands which show 

 clearly on the general flesh tint of the shell. The specimens appear 

 to be fossil or subfossil, because of the reddish mineral matter coat- 

 ing them in spots. This shell is evidently a subspecies of Oreohelix 

 yavapai Pilsbry, the type of which comes from Yavapai County, 

 which adjoins Oconino County. It is much larger than Oreohelix 

 yavajmi but has essentially the same sculpture. In dimensions it 

 approaches but is slightly larger than Oreohelix yavapai mariae 

 Bartsch, the type locality of which is near the mouth of Gallatin 

 Canyon, Mont. Its sculpture is much more pronounced than that of 

 Oreohelix yavapai mariae, in which the sculpture usual to the group 

 is not clearly defined. 



OREOHELIX HOUGHI, r.ew species 



Plate 1, Figures 7, 8, 9, 10 



Shell depressed, low conic, upper surface of whorls slightly rounded. 

 Early whorls (as shown by young shells) sharply angled, and with a 

 white cordlike keel which fills all the sutures to the aperture, in front 

 of which the keel disappears but the periphery for a short distance 

 remains angular. On the back of the body whorl the angle fades 

 out and just behind the aperture the whorl is well rounded. Upper 

 part of each whorl attached to under side of the carina. Earliest 

 whorls brownish, with a number of transverse riblets. Later growth 

 pallid, with periodic transverse stripes which continue across the base 

 to the umbilicus. Base nearly white. A faint narrow brown band just 

 below and one just above the periphery. Spiral sculpture lacking. 

 Transverse sculpture of numerous fine retractive growth riblets. 



