154 



PROCEEDIXaS OF THE NATIONAL MUSEUM. 



VOL. XXXI. 



evaneacent; diameter, major, 12.5; minor, 9.0; iieight, 2.0; length of 

 free portion of whorl varying- from 1.0 to 3.0 mm. Diameter of aper- 

 ture, long, 3.0; .short, 2.0 mm. 



Hahitat. — Alvarez iSIountains, San Luis Potosi, at 7,200 feet eleva- 

 tion; Dr. Edward Palmer, of the U. S. Agricultural Dept. 



Type.~OAi. No. 110385, U.S.N.M. 



The remarkable feature of this animal, apart from its discoid form, 

 is the manner in which the termination of the last whorl is freed from 

 the rest and turned upward, as in Anostoma or Ilypselostoma^ so that, 

 in crawling, the shell must be dragged on what would ordinaril}' be the 



f^-^ 



^, 



Fig. 14. 



..p.v. 



-//- -^4 



Fig. 15. 



Fig. 16. 



Fig. 13. — Sketch of jaw of Hendersoniella palweri. 



Fig. 14.— Teeth of radula, showing (1) rhachidian, first three laterals, ninth lateral, and outer lateral. 

 Fig. 15. — Anatomical details; k, kidney; O. I, intestine; p. r., pulmonary vein; d, lung. 

 Fig. 16. — m., mantle; c. m., contractor muscle, h, heart: k, kidney; G. 3, undeveloped genitalia; 

 L, liver. All magnified; taken from drawings by Dr. H. A. Pilsbry. 



upper surface; a fact which is confirmed by the worn condition in each 

 case of this pai't of the shell. The aperture strongly recalls that of 

 UTocoptlx^ suggesting at first glance that we have to do with a discoid 

 member of that family. However, the internal lamina and the general 

 aspect of the shell, except the umbilical region, are not very unlike 

 the discoid Polygyras. 



One of the two specimens containing the animal was su))mitte(l to 

 Doctor Pilsbr}' as the most competent expert in the anatomy of the 

 Pulmonata, who reports as follows: 



"The specimen was preserved in alcohol and had retreated somewhat more than 

 one whorl within the aperture. It was otviic 1 by ilissolving the upper surface of 



