46 THE NAUTILUS. 



of (). piufnuca Pils. and seven tlead sliells of 0. s. obscura were 

 also found here. The extri initdtis from tliis canyon are much 

 le.ss prominently carinated than those from Sliell Creek 

 Canyon. 



Sta. 248, at base of bluff from 100 to 150 yards east of Sta. 

 247, under fairly good cover of shrubbery. 0. c. obscura nu- 

 merous, witli (|uite a number 0. y. rrtremitatis (two albinos) 

 and a few O. pygnucu. 



Sta. 249, a short distance up the canyon from Sta. 248, 

 where the ve^retation about small rock slides at the foot of a 

 high clift' forms good cover for snails, which were very abun- 

 dant. In a short time we observed 600 live 0. pygmcea, the 

 same number of 0. c. obscura, and ."iS live 0. y. extremiiatts. 

 Four of the pygnucu and six of the obscura are albinos. 

 Oreohelix cooperi obscura new form. 



Ordinarily forms of Oreohelix based upon color alone are 

 of doubtful value, but in this case the color is so striking and 

 so uniform that I feel justified in giving to the form from 

 this canyon a name. Of the hundreds of live examples and 

 more hundreds of dead shells examined from stations 246, 

 247, 248 and 249, not one resembles typical cooperi in color, 

 though I detect no other difference. With the exception of 

 The eight albinos, they are all very- dark, mostly quite black, 

 not dark red or bro^v^l usually, -with a rather broad light 

 peripheral band, though this is wanting in many examples. 

 In color they resemble 0. peripherua albofasciata (Hemph.), 

 but would not be mistaken for that form by anyone familiar 

 with Oreohelices. In mimbering thousands of 0. cooperi in 

 t.lie last few weeks I have noticed that there is a scratch be- 

 neath the pen, as though it were being dragged across a fine, 

 sharp file, quite different from the sensation experienced in 

 using the pen on other species, of which I have numbered 

 thousands recently. This scratch I noticed in the color form 

 now described. 



Most of the shells of the yavapai group in White Creek 

 Canyon have the spire much more elevated, scarcely any 

 being as flat as those from Shell Creek Canyon, and, as would 

 he expected, the keel is much less pronounced. In fact, many 



