40 THE >fAUTILUS. 



whorls and sculpture, except that the Shiviekii is more strongly, reg- 

 ularly ribbed above. It differs from limatulus in being far more 

 robust, more elevated, with rounder mouth and narrower, deeper 

 umbilicus. Upon comparing specimens of the two species, I am sur- 

 prised that they were ever confused; for, except in sculpture, the 

 Z. Shimekii is far more like Z. nitidiis than to Z. limatulus. The 

 specimens described and figured were collected by Prof. B. Shimek, 

 of Iowa City, Iowa. 



This form is interesting as being the only well-defined species of 

 Loess fossil which seems to have become extinct ; although there are 

 a number of others, such as Helicina occulta and Patula strigosa var., 

 which survive in greatly reduced numbers in a few limited locali- 

 ties, or only in a distant part of the country. 



This species is rather widely distributed throughout the Loess 

 formation of Iowa and eastern Nebraska. The name is bestowed 

 in memory of the many happy days s[)ent together by Prof. Shimek 

 and the writer, then college classmates, hunting fossils and shells. 

 Fig. 12, 13, 14, Helix (Polygyrella) Harfordiana. 



Dcedalochila Harfordiana Cooper, Amer. Journ. of Conch., vol. 

 V, pt. 4, 196, plate 17, fig. 8. See also torn, cit, p. 214. 



Helix (Dcedalochila) Harfordiana Coop., Tryon, ^lanual of ("on- 

 chology, 2d Series, vol. Ill, p. 130, pi. 27, figs. 55-57. 



Polygyra Harfordiana Coop., W. G. Binney, Manual of X. A. 

 Land Shells, p. 114, fig. 81, but not the. description I 



Not Triodopsis Harfordiana Cp., W. G. Binney, Terr. ^[oll. U. 

 S. etc., V, p. 309, fig. 203, 1878. 



This shell has been so much misunderstood and so incorrectly 

 figured that I feel impelled to refigure it and to offer a few sugges- 

 tions concerning the systematic position of the species. It was dis- 

 covered in the year 1869 by Mr. AV. G. W. Harford in the " Big 

 Tree" district, Fresno County, California. The locality is an ele- 

 vated one, lying 6500 ft. above the sea level, in lat. 37°. 



In thus devoting space to the consideration of this question of 

 systematic position, I do not wish to be understood to attach any 

 great importance to those divisions of our Helices which some 

 authors call sections, some subgenera, and still others designate as 

 full fledged genera. I am fully aware that many of these divisions 

 coalesce ; we can no more trace the separating line between their 

 species than Ave can unmix mingled milk and water. Thus, the 

 species Texasiana, triodontoides and Levettei bridge the space between 



