1906.] NATURAL SCIENCES OF PHILADELPHIA. 139 
be retained as a distinct species, then the race pecosensis will be rele- 
gated to it as a variety. 
Some specimens of pecosensis taken about thirty years ago by Dr. 
H. C. Wood, probably, as he informs me, from somewhere in the 
‘Great Bend’’ of the Rio Grande, were noticed in the Manual of 
Conchology, Vol. XI. 
Bulimulus dealbatus pasonis Pils. Pl. VI, fig. 25. 
Pilsbry, Nautilus, XVI, July 1902, p. 32. 
The shell is smaller and more slender than any other form of deal- 
batus, the diameter about half, the aperture less than half the total 
length of the shell; nearly smooth, being sculptured with irregular 
erowth-wrinkles only. The dead specimens are dull reddish-corneous 
with some streaks and mottling of opaque white. Whorls 5} to 6, 
quite convex. Aperture small, ovate, the insertions of the lip and 
columella markedly approaching, without an internal lip-rib in the 
specimens seen. Umbilicus comparatively large. 
Alt. 15.7 15.3 mm. 
Diam. 7.5 ie ea 
Aperture 6.8 GES 
Franklin mountain, near El Paso, Texas. (J. H. Ferriss.) 
This is the most distinct, as it is the most remote, of the races of B. 
dealbatus, and unless connecting forms come to light, it may well be 
given specific rank. The absence of regular striation on the spire, 
the converging ends of the lip and the diminutive size combine to give 
it individuality. As yet but few specimens have been found, and in 
a single place. Some individuals of the Val Verde county B. d. 
ragsdalei approach pasonis in size, but in a series of about 200 examined 
none approach the other characters of the present race. 
Bulimulus alternatus marie (Albers). Pl. VII. 
Die Heliceen, p. 162 (1850). 
Binney, Terr. Moll., V, p. 390, figs. 272, 273, pl. li a, upper and lower figs. ; 
pl. li 6, all figs. 
This species is recognized by its dense, solid, calcareous texture, 
oblong shape and colored, usually dark brown or purplish interior, 
and by the great length of the penis and spermathecal duct. Its range 
extends in a wide belt along the Rio Grande, from the Gulf at least to 
the Pecos river. How much farther west we do not know. 
B. marie was named by Albers for his daughter Mary, having been 
recognized as distinct on her birthday. The type, figured by Pfeiffer, 
is a ragged-striped shell with only a low prominence, hardly to be called 
