1905.] ' NATURAL SCIENCES OF PHILADELPHIA. 253 



upper part. The spermatheca is long and narrow, its duct ratlior 

 short. The epiphallus and flagelhim measure 22 mm.; flagellum 2 

 mm.; spermatheca and duct 20 mm. The specimens had been placed 

 in alcohol without drowning. 



The jaw (PI. XXIII, fig. 16) has seven ribs, grouped in the median 

 half, the ends smooth. 



The rad\ila (PI. XXII, fig. 8) has about 38.1.38 teeth. The ecto- 

 cones are developed on central and lateral teeth. From the twenty- 

 fourth or twenty-fifth teeth outward from the middle the inner cusp 

 is bifid. The ectocones are unsplit. A central and two lateral teeth 

 are shown. 



This snail, so far as the slieU is concerned, would be referred without 

 hesitation to A. chiricahvana; the differences being less than the ordi- 

 nary range of individual variation in Ashmunella or Polygyra; but the 

 genitalia are so utterly unlike in the two forms that it is obvious that 

 they are not even nearly related. From the granulation and the weak 

 traces of teeth it seems that A. metamorphosa is probably a toothless 

 derivative of the A. levettei stock; I regret that I have no alcoholic 

 specimens of A. levettei or A. I. heterodonta for comparison. ^4. esuritor 

 differs from metamorphosa by its angular or distinctly subangular 

 periphery, rougher siu-face when perfectly fresh, and perhaps somewhat 

 wider umbilicus; but it must be admitted that the two forms are so 

 similar that their distinction may be difficult without an examination 

 of the soft parts. The genitalia, however, are so very different that 

 the two species cannot even be closely related. They must be inde- 

 pendent derivatives from toothed ancestral forms. 



I dissected two of the three specimens received. They could be 

 extracted only by breaking into the shell. Having been preserved in 

 alcohol without drowning the specimens were much more contracted 

 than the A. chiricahuana and A. esuritor I examined. A somewhat 

 extensive experience with snails in all conditions of preservation has 

 shown that beyond a moderate diminution of the absolute size, the 

 characters of the genitalia are not altered by preservation of the animal 

 in strong alcohol. 



Genus SONOfiELLA Pilsbry. 



Pilsbry, Proc. Acad. Nat. Sci. Phila., 1900, p. 556 (definition, anatomy); 

 Bartsch, Smiths. Misc. Coll., Vol. 47, p. 187, 1904 (monograph). 



The soft anatomy of this genus has hitherto been known in a single 

 species. The study of numerous specimens of several species enables 

 me to extend the generic characterization. 



The shells in these Helices, while interminably modified locally in 



