272 PROCEEDINGS OF THE ACADEMY OF [Mch., 



in most colonics there is great individual variation in the extent to 

 which it has been replaced in the adult stage by a rounded periphery. 

 Oreolielix strigosa (Old.)- 



Various forms referable to strigosa occur in New Mexico, such as those 

 sent from the Red river (Ashmun), Pecos (Cockcrell), Canyon Diablo, 

 near Rowe (Miss Cooper), and Big Spring, 5 miles east of Zuni (H. S. 

 Conard). They are two-banded, with the periphery of the last whorl 

 rounded, not differing from the forms commonly found farther north, 

 but slightly unlike the typical Northwestern strigosa. The exact affini- 

 ties of these forms await further investigations now in progress. 



I have examined the internal anatomy of specimens fiom Pecos, 

 New Mexico. The shells are either rounded or subangular at the 

 periphery in adults. Sculpture of sharp, irregular growth-wrinkles 

 or striae, decussated by slightly impressed spiral lines both above 

 and below. The color varies from yellowish Isabelline to light 

 reddish, with paler striae, always with two narrow bands, and in one 

 specimen a third band around the umbilicus. The embryonic 

 shell is strongly carinate. The first whorl is convex and almost smooth ; 

 then fine, regular, obliquely radial striae appear, and continue to the 

 end of the embryonic shell of 2 to 2-J- whorls; over them there is an 

 extremeh^ minute regular spiral striation, and on the last half whorl 

 coarser, spaced spirals (PI. XXV, figs. 45, 46, 47). 



The specimens examined were taken August 9, 1903. The penis is 

 very long and strongly twisted. The basal third of its length is cylin- 

 dric, the rest more or less lank, partially collapsed. Internally the 

 basal third (5 mm.) is rather finely plicate longitudinally, thick-walled ; 

 the rest has larger lumen and thinner walls, which are densely papillose 

 within, the distal half having three low fleshy internal ridges. The 

 penial retractor is inserted upon the end of the penis and the base of 

 the epiphallus, which is decidedly less than one-half the length of the 

 penis. The vagina is subcylindric. The uterus is distended with 

 embryos, of which there are 9, with shells 3 to 4 mm. in diameter (PI. 

 XI, figs. 14, 15). Each is enclosed in a membranous capsule, ap- 

 parently the podocyst. Some of them seem to have a small cephalic 

 vesicle. The other 9 organs call for no especial notice (PI. XIX, fig. 3). 



The pallial organs have been described above. The kidney is 6.7, 

 the pericardium 4.6 mm. long. 



The foot is slate-blackish and finely granular alcove, the dorsal fur- 

 rows distinct. The distinct genital furrow is duplicated on the left 

 side. 



The jaw (PI. XXIII, fig. 25) has fine vertical striae. 



