234 PROCEEDINGS OF THE ACADEMY OF [Mch., 
This form has hitherto been referred to A. chiricahuana, from which 
it differs chiefly in the greater inflation of the latter part of the last whorl. 
This is noticeable in a side view, and is seen prominently above the 
aperture in a front view. It differs from A. pseuwdodonta capitanensis 
chiefly by wanting basal teeth. 
In such simplified forms as this, it is not easy to determine the true 
relationships by the shell alone. When the genitalia can be examined 
the affinities of A. ashmuni and A. a. robusta will doubtless become 
clear. There is an albino in Mr. Ashmun’s collection. 
Group of A. thomsoniana. 
Aperture of the shell with parietal, outer and basal teeth, the latter 
often bifid, divided into two contiguous tubercles. Length of the sper- 
matheca and its duct 60 to 65 per cent. that of the penis, epiphallus 
and flagellum in known forms. 
These forms are from northern central New Mexico. They have been 
investigated chiefly by Prof. T. D. A. Cockerell and his pupils. 
By their genitalia and shells they are related to the southeastern 
Arizona group. Three forms are perhaps sufficiently differentiated to 
require names: A. t. portere, A. thomsoniana and A. t. pecosensis. 
Ashmunella thomsoniana (Ancey). PI. XIII, figs. 27-30. 
Helix levettei Bland var. thomsoniana, and var. orobena Ancey, Concholo- 
gist’s Exchange, II, p. 64 (November, 1887). 
Ashmunella thomsoniana (Anc.) Pils. and Ckll., Proc. Acad. Nat. Sci. Phila., 
1899, p. 192; Ancey, Jour. of Malac., VIII, p. 75, 1901; Pilsbry, Proc. 
Acad. Nat. Sci. Phila., 1900, p 108, fig. 2 (genitalia of specimen from Santa 
Fé canyon); Ckll. and Cooper, Nautilus, XV, p. 109, February, 1902, 
with mut. alba C. and C., 1. c., p.110 (Canyon Diablo) ; Ckll., Nautilus, XVI, 
January, 1903, p. 105 (Pecos Pueblo). 
Ashmunella thomsoniana coopere Cockerell, Nautilus, XV, p. 35, July, 1901. 
A. t. antiqua Ckll. and Coop., Science, December 27, 1901, p. 1,009; Nautilus, 
XV, p. 110 (Pleistocene, Las Vegas). 
Specimens from J. H. Thomson, part of the original lot from Santa 
Fé Canyon, are before me, and two are illustrated (Pl. XIII, figs 
27, 28). 
It is narrowly umbilicate, brown and glossy, finely striate, with very 
faint traces of incised spirals on the last whorl. There are 5 whorls. 
The characters of the aperture are sufficiently shown by the figures, the 
only ones published to this time. The basal tooth is simple in all 
specimens I have seen from the type canyon. 
Alt. 6.9, diam. 13 mm.; whorls 5. 
ae “54. 
‘oo, °° | toe Oe. 
The specimen I dissected in 1900, collected by Prof. Cockerell at 
