THE NAUTILUS. 



VOL. XXIX. JUNE, 1915. No. 2 



THE NEW MEXICAN EXPEDITION OF 1914-ASHMTJNELLA. 



BY H. A. PILSBRY AND JAS. H. FERRISS. 



Few shells have been collected in the Mogollon range, in the 

 western part of Socorro County, New Mexico, prior to the re- 

 connaissance made by one of us and Mr. L. E. Daniels. The 

 only Ashmunella known from there was A. mogollonensis Pils., 

 collected by Prof. E. 0. Wooton in 1900. In the limited time 

 spent there last summer only a few canyons on the southwestern 

 slope were explored, so that this paper, and those on the other 

 genera to follow, may be regarded as a mere sketch of the snail 

 fauna, to be filled out by further field-work. The localities 

 mentioned may be found on the Mogollon Quadrangle of the 

 U. S. Geological Survey Topographic Map, a rough tracing of 

 which is given in Fig. 1, with the positions of collecting stations 

 indicated by their serial numbers. 



The affinities of the snails seem to be with the Chiricahuan 

 fauna. The species of Ashmunella are different, but they have 

 an unmistakable Chiricahuan appearance. This leads us to 

 believe that they were evolved from the same ancestral species, 

 which must have been in Pliocene times able to migrate over a 

 great area now destitute of snails. 



The gorges in the canyons of the south-west side of the Mo- 

 gollon mountains were so narrow that the talus ran down to the 

 edges of the stream, well shaded by the cliffs and the trees. 

 Conditions were much alike with the different colonies except 



