386 PROCEEDINGS OF THE ACADEMY OF [Juiie, 



forming tangents and V-shaped figures on the last embryonic whorl, 

 as well as in various features of the adult shell. 



We do not find in the shells of the Warren form any constant 

 difference from those of the type locality; but the genitalia (PI. XI, 

 fig. 2) and jaw (PI. XI, fig. 26) differ somewhat in the only living 

 adult taken. The penis has scarcely any sheath; only a few fibres 

 bind the epiphallus. Flagellum more minute. Penis-papilla (fig. 

 2a) nearly half the length of the penis, tapering and wrinkled. The 

 penial retractor is inserted on the epiphallus near its base. The 

 vagina is nearly as long as the penis. Length of penis lOJ mm.; 

 epiphallus 10 mm.; penis-papilla 5 mm.; vagina 9 mm. 



The jaw (PI. XI, fig. 26) has about 5 weakly developed ribs. 



Thysanophora hornii (Gabb). 



Limestone hill 2 miles east of Warren. 

 Holospira arizonensis mularis n. subsp. PL XV, figs. 8 to Se. 



The shell is very shortly rimate, cylindric, with short terminal 

 cone, wood brown or avellaneous, the last half of the last whorl 

 opaque white; composed of 10| to 13| whorls, the first two smooth. 

 The last half of the second and first half of the third whorl are narrower 

 than the preceding and following whorls, as usual, and the apex 

 projects somewhat nipple-like. Following whorls of the cone are 

 quite convex, and are sharply, closely and obliquely striate. On 

 the cylindrical portion the whorls are only weakly convex, and 

 gradually lose the striae, so that the penultimate and often one or 

 two earlier whorls are smooth or nearly so, the last half-whorl becom- 

 ing strongly, sharply striate again. The last whorl is compressed 

 laterally on the back but becomes rounded near the aperture, pre- 

 ceding which it is somewhat contracted. The aperture is rotund- 

 ovate, peristome shortly free of the preceding whorl, and quite 

 narrowly expanded. Internal axis rather small, in the last part of 

 the penultimate and the beginning of the last whorl becoming a 

 moderate, obtuse lamella. Typically there are no other lamellae, 

 but in a small number of specimens a superior lamella, or superior 

 and basal lamellae are developed, both very weak. 



Mule Mountains, on the northern slope of the Escabrosa Ridge, 

 west of Bisbee, Arizona, at about 6,000 to 6,500 feet elevation. 



