THE NAUTILUS, 99 



dilate types will be found to arise from paucispiral nuclei. 

 These extremes of operculum development are seen to be corre- 

 lated generally with advanced development of other organs. A 

 final stage is here apt to occur in which the operculum is alto- 

 gether lost. 



The course of evolution here sketched has not marched regu- 

 larly through the gasteropod phylum. On the contrary it is 

 suggested that in several different groups the operculum has 

 strayed independently along this road of degeneracy. 



A SHELL HUNT IN THE BLACK £\NGE, WITH DESCBIPTION OF 

 A Ni-W OREOHELIX. 



BY JAS. H. FERRISS. 



A stop-over at Deming in the summer of 1915, to shake hands 

 with Dr. Swope, deflected the firm of Pilsbry & Ferriss in their 

 snail explorations from the Mogollon Mountains, via Silver City, 

 to the Black Range, via Cook's Peak. Samuel D. Swope, M. D., 

 promoter of civic prosperity, friend of conservation and science, 

 knew the unexplored snail country, and with bake ovens and 

 tactful advice sent us to the biggest mountain range in New 

 Mexico. 



Cook's Peak, one of the earliest land-marks of California 

 overland emigrants, interesting botanically and historically, had 

 no encouragement for us in conchology. At the post office of 

 Swans, on the Mimbres river, we transferred from a heavy 

 wagon and its mule team to a pack train of horses, sufficient 

 for two ladies, two men and a camp outfit. In that exchange 

 we got Teodoro Solis, formerly of Chihuahua, the best packer 

 and camper alive. 



A large colony of Ashmunellas was found in the foot hills. 

 The next day at Mitchell Gray's mining cabin on Silver Creek, 

 well up the side of Sawyer's Peak, both Ashmunellas and Oreo- 

 helix came out to meet us a few feet from camp. We reveled 

 here a week or so with the snails of Sawyer and then followed 

 the continental divide northward. Sierra county on the right, 

 Grant county on the left. 



