14 THE NAUTILUS. 



I have found shells at 10,000 feet alt., and other collectors still 

 higher. I once walked fifteen miles in one day. and upset rocks and 

 logs enough, 1 should think, to materially change the appearance of 

 the entire locality, and had to take a train at 10 p. m. and ride till 3 

 o'clock. After a day of this tramping, climbing and lifting, without 

 finding much, I have asked myself, Does this pay? hut have heen 

 just ;is eager to improve the next opportunity, no matter how much 

 hard work it involved. 



Sometimes the most promising locality has yielded nothing of spec- 

 ial interest, while a less likely field has produced new species. Espec- 

 ially has this been the case in places that at first seemed too dry to 

 be worth investigating, but which have later been found to contain 

 minute forms, especially Pupidae. This fact, taken in connection with 

 their minuteness, accounts mainly for the new Bifidaria: being mostly 

 recent finds. 



A horseback ride of twenty miles from Crittenden, Arizona, with 

 a companion, brought us into the Santa Rita Mountains, where we 

 camped one night with no roof but the blue canopy. A half day's 

 collecting in what seemed a very promising canon resulted in only 

 about forty specimens all told ; but when I found the lot to contain 

 Bifidaria pilsbryana, further west than before known, and the first 

 examples of Bifid, ashimuii Sterki, my disappointment was percep- 

 tibly mollified. 



One Monday morning I walked four miles up the very dry Eph- 

 raim canon, having to be back in just four hours from the time of 

 starting. I covered the eight miles, had two hours for collecting, and 

 was back on schpdule time with but few shells, but they included 

 Bifidaria perversa Sterki, and Bifid dalliana Sterki, both n. sp., and 

 Bifid, ashmuni form minor. The representatives of this genus are so 

 minute that they easily elude one's search, especially in dark canons 

 and beneath thick undergrowth; and 1 have found it of advantage, 

 particularly when my time was limited, to gather the dirt and leaves 

 found to contain them and carry it away. I usually have a flour sack 

 in my pocket for the purpose. About a peck of such dirt taken home 

 from Jerome, Arizona, nearly 500 miles, "panned out" 93 Bifid, 

 hordeacella var. parvidens Sterki, n. var., and about 40 Thysanophora 

 horni Gabb, but it took many hours to look it over. At the present 

 writing, I have dirt from five different localities, ranging from 100 

 to 850 miles from home, perhaps two bushels in all, waiting to be 



