246 PROCEEDINGS OF THE ACADEMY OF [Mch., 



in angulata, convex in angigyra. Moreover, the genitalia of angigyra 

 and angulata differ in important respects. • 



As usual in Ashmunella and many other snails, the "species" is 

 composed of a group of varying colonies, all living in Cave Creek Can- 

 yon and its branches. The largest and best developed of these has 

 been taken as the type lot, PI. XIV, figs. 55-57. 



Another lot (87,015) from the South Fork of Cave Creek, "under 

 cliffs" (fig. 58), has smaller shells of a paler dull brown tint. The whorls 

 after the first 1^ are flattened; and there is sometimes a low ridge 

 making the parietal tooth V-shaped. 

 Alt. 12.8, diam. 6.5 mm.; whorls 6^. 

 " 11.8, " 5.6 " " 6. 



" 12, " 5.6 " " 61. 



Another lot, from a different spot from the above, also consists of 

 small shells;: 



Alt. 5, diam. 11 mm.; whorls 6 (2 specimens). 

 " 5.3, " 11 " " 6i 



" 5.3, " 10.7 " " 6. 



" 4.8, " 9.9 " " 5f. 



The following lots are from Cave Creek Canyon (the preceding being 

 from its south fork) : 



No. 87,111 (fig. 61) is almost exactly like 87,015 (above). 

 No. 87,020 (figs. 59, 60) varies more in size and shape, as follows: 

 Alt. 6.3, diam. 11.2 mm.; whorls 6^. 

 " 5, " 11.3 " " 6^ 



" 5, " 11 " " 6^. 



" 4.8, " 9.9 " " 6. 



The punctation of the spire is well developed. 



At the Falls in Cave Creek (figs. 63, 64) the shells are like the preced- 

 ing lot, except that the punctation is less developed and the umbilicus 

 frequently smaller : 



Alt. 5, diam. 11 mm.; width of umbilicus 2 mm. 

 " 4.4, " 9.8 " " " 1.5 " 



" 5.5, " 11 " " " 2.5 " 



The genitalia of A. angulata (PI. XXI, fig. 26) are figured from a 

 specimen from the south fork of Cave Creek, No, 87,015, A. N. S. P. 

 The penis is very short (long in angigyra, see fig. 28) ; the epiphallus, 

 on the other hand, is very much longer than in angigyra; while the 

 spermatheca and its duct are of about equal length in the two species. 

 The vagina in A. angulata is rather long, as usual in Ashmunella, while 

 in A. I. angigyra it is much shorter than in any other Ashmunella I have 

 dissected. 



