Occasional Papers of the Museum of Zoology 45 



oblique, transversely elliptical. Peristome: thickened and 

 slightly reflected, especially on the palatal wall. 



While this variety seems simply a dwarfed form of P. dun- 

 kcri, it appears to be at least an ecological race. While the 

 type is clearly an adult shell, the smaller numl^er of whorls 

 appears to indicate arrested development as well as actual re- 

 duction in size. The largest adult from this locality is consid- 

 erably more elevated, and thus a])proaches the next form in 

 shape. Both of the larger shells have 4'4 whorls. 



Attention is called to the fact that the type of this iorm^ 

 is less than >^ as large as P. dunkcri. or the largest shell in 

 the Estacion Tachira series ; while these latter are almost 2/3 

 as large as P. gkjantea (Sowerby). The correspondence of 

 P. dunkcri and P. quifciisis with the forms of P. gigantca and 

 P. g. fisclicri, has already been noted. In addition, the last two 

 forms usually have a larger number of whorls than do the 

 smaller shells. 



Poteria dunkcri, var. approaching P. popa\ana (Lea). 

 Fig. v-T. 



Three adults and 8 immature specimens from the creek flats 

 of Ouebrada Santa Aguita. near La Fria (H. L b. 42). These 

 shells are quite heavy and are considerably more elevated than 

 most of the others from the same general region. The ground" 

 color of tb.e adults is dark brown, so that the spiral l)anding 

 is partially ol)scured. The shell substance at the apex is rosa- 

 ceous to coral red. The aperture is nearly circular, and the 

 peristome is thickened but not at all reflected. The umbilicus 

 is about % the major diameter. 



As will be seen from the table of dimensions, this form ap- 

 proaches P. popayaiui in shape. However, in the specimens- 



