392 TRANSACTIONS OF THE WAGNER FREE 



lip broken away in the type. Alt. of .shell 13 ; diameter probably about 15 

 mm. when perfect. 



This variety differs from the type by the elimination of much of tiie spiral 

 sculpture, by the beading of the posterior peripheral keel and of several of the 

 spirals near the umbilical region, and the absence of the peripheral channel. 

 The intercalary threads are also much finer and more numerous and the shell 

 more depressed. 



Oalliostoma philanthropus var. basicutn Dall. 



Chesapeake Miocene of Petersburg, Va., H. C. Lea. 



This variety has the beading very prominent on all the spirals of the 

 upper surface, the posterior peripheral keel very .strong and beaded, the spirals 

 of the base, to the number of six, very strong, simple, with excavated inter- 

 spaces, sometimes with an intercalary fine thread. This form leads directly 

 toward C. Mitclielli Conrad, which, in its typical features is markedly differeTit 

 from the typical pliilantliropus. In fact, it is almost exactly intermediate be- 

 tween the two forms. 



Oalliostoma (philanthropus var. ?) Conradianum Dall. 

 Plate 22, figure 34. 



Chesapeake Miocene (of Petersburg, Va. ?) collection of the Academy of 

 Natural Sciences at Philadelphia. 



Shell large, turbinate, with one or two smooth nuclear and eight or more 

 subsequent sculptured whorls ; shell above the periphery slightly excavated 

 or fiattish, the periphery marked by a stout sculptured prominent spiral band 

 ill the earlier whorls, becoming obsolete on the last whorl and a half; suture 

 distinct, wound some distance below the periphery ; base moderately rounded, 

 as is the periphery of the last whorl ; spiral sculpture of (on the early whorls 

 about three) beaded spiral lines, that at the periphery straplike, with the bead- 

 ing squarish, those above narrow and with the beads more rounded ; these 

 increase with the growth of the shell by intercalation, the intercalary threads 

 appearing first as a simple elevated line, then wavy and at last beaded ; between 

 the periphery and the suture in front are one or two more smaller, rippled 

 lines, which in the last whorl or two become divided into numerous subequal, 

 fine, somewhat wavy, elevated lines, merging with those into which the periph- 

 eral band becomes similarly modified, so that the finest and least prominent 

 spiral sculpture of the shell on the last whorl or two is found on the periph- 

 ery ; base in the adult with similar wavy, somewhat alternated spirals, the 

 primaries gradually increasing in size toward the axis; transverse sculpture 

 of flexuous incremental lines, rather feeble, and most noticeable on the base; 

 aperture subquadrate, oblique, with the outer lip thin-edged and nearly smooth 

 within, the pillar simple, smooth, concave, with a moderate fasciole on the 

 base behind it, but no pit or umbilicus; the body with a thin wash of callus. 



