THE NAUTILUS. 69 



Dr. Pilsbry in the paper before us, so far as they relate to the 

 Urocoptidse and Helicidse. A second paper, on the small species, is 

 to appear later. 



The paper is full of detail and profusely illustrated, so that it 

 practically covers the ground, so far as present knowledge will per- 

 mit. It has the lucidity and precision which we have learned to ex- 

 pect in Dr. Pilsbry's writings, presenting the facts in such a manner 

 that the reader can judge for himself, whether he will agree with the 

 conclusions reached or not. 



In the Urocoptidse, the genera Holospira and Microceramus are 

 described. The latter includes M. texanus (Pils.), of Texas, but 

 does not enter New Mexico or Arizona. Holospira has a species 

 confined to Texas, one common to Texas and adjacent New Mexico, 

 five apparently peculiar to New Mexico, and four only known from 

 Arizona. They seem to be often confined to a single range, two 

 species being sometimes found living together. Four new ones are 

 described : H. ferrissi from the Huachuca Mts., H. cionella from 

 Fort Bowie, Ariz., H. regis Pils. and Ckll., from near Kingston, 

 N. M., and H. chiricahuana from the Chiricahua Mts. 



The Helicidas of Arizona and New Mexico include five genera : 

 Ashmmella, Sonorella, Oreohelix, Polygyra and Thysanophora. The 

 last is to be treated later on, and Polygyra is dismissed with the re- 

 mark that it just enters New Mexico, one species — P. texasiana — 

 having been found in the Pecos Valley. It is worth while to note 

 here that these Polygyras were collected by Professor Tinsley, who 

 subsequently took me to the locality where they occur. They exist 

 exclusively, so far as I could learn, in a bed of white marl close to 

 the Pecos river, and they are to be regarded as pleistocene fossils. 

 It is quite probable that Polygyra has been long extinct in New- 

 Mexico ; but if it still survives there the fact remains to be discovered. 

 The fossil shell is probably worthy of a subspecific name, as it is not 

 typical texasiana. 



Incidentally, one may be excused for remarking that the pleisto- 

 cene beds of the southwest urgently need investigation. They are 

 abundant in New Mexico, at least, and there is no doubt that they 

 will throw much light on the past history of the snails of that region. 

 Unfortunately, it is usually impossible to form any good estimate of 

 their age, for shells are well preserved in the dry soil, and speci- 

 mens ten thousand years old may not look materially different from 



