1905.] NATURAL SCIENCES OF PHILADELPHIA. 227 
account of his collecting in Utah, and by Ferriss, who in speaking of the 
Huachueas says, “Every colony in the canyon was liable to have some 
distinctive mark in size, color or form. .... No two colonies seemed 
exactly alike, and they did not visit back and forth, nor travel far from 
the best part of their own rock pile” (Nautilus, XVII, p. 51). 
When through some means two slightly differentiated colonies inter- 
mingle, as they occasionally must, hybridism follows, and a complex 
progeny issues, such as I have found in the Floridian Liguus. Who 
can unravel the tangled threads of affinity when the modified forms of 
two or more canyons reach each other across a divide! It is as complex 
as a modern human community, where subraces are mingling blood 
after centuries of pure breeding. 
Group of A. rhyssa. 
In species of this group, small basal and parictal teeth are often 
present, but there is no outer lip tooth. The spermatheca and its duct 
are about half the length of the penis, eprphallus and flagellum, or even 
less. The combined length of the penis, epiphallus and flagellum is 
decidedly less than three times the diameter of the shell. The penis 
is comparatively well developed. 
This group is especially characteristic of the Capitan, White and 
Sacramento ranges of southern-central New Mexico, east of the Rio 
Grande. The forms now known arrange themselves in three series, 
thus: 
robusta capitanensis hyporhyssa altissima 
ashmuni pseudodonta miorhyssa rhyssa townsendi 
. $e 
is oe ee 
Peed ‘ ee 
Tee oe tae 
The central and right-hand groups are known to be related by the 
genitalia. The group on the left is separated from these geographically, 
and its relationships must remain wholly uncertain until the soft parts 
can be examined. 
Ashmunella rhyssa (Dall). Pl. XI, figs. 1-4. 
Polygyra rhyssa Dall, Nautilus, XI, May, 1897, p. 2 
Ashmunella rhyssa Dall, Pils. and CkIL, Proc. Acad. Nat. Sci. Phila., 1899, 
p. 192; Dall, Proc. U.S. N. Mus., XXIV, p. 500, Pl. 27, figs. 11, 14. 
