230 SYNAPTEKPES. 



mm. long. The axis is distinctly rimate. The shell is very 

 pale yellowish-white. 



3. S. WALLISI (Mousson). PI. 36, figs. 85, 86. 



Shell subperf orate, turrite, decollate (defective?), very 

 thin, striatulate, polished, ornamented with very fine, im- 

 perfect decussating lines, subdiaphanous, milky whitish. 

 Spire defective; suture simple, slightly impressed. Fouir 

 whorls remain, slowly increasing, piano-icon vex, last 

 not descending, obtusely angular, rather flattened above, 

 more convex below. Aperture slightly oblique (18 degrees 

 from the axis), widely ovate, obtusely subquadrate basally. 

 Peristome straight, acute, a little expanded, the margins 

 remote, subparallel, right margin less curved above, more 

 at the base ; columellar margin shortly and broadly refiexed 

 and appressed at the insertion; obliquely cut off below. 

 Columella somewhat twisted, passing into the retracted basal 

 margin. Length of defective specimen 26, diam. 12 mm. 

 (Mouss.). 



Colombia: lower Magdalena valley (Wallis). 



Stenogyra wallisi Mouss., Malak. Blatter xvi, 1869, p. 178. 

 -PFR., Novit. Conch, p. 146, pi. 133, f. 10, 11. Bulimus w., 

 PFR., Monogr. viii, 131. 



Mousson received two examples of this fragile Stenogyroid, 

 both similarly broken, without a septum or plug to close 

 the breach. Besides the delicate whitish and polished but 

 finely lineate surface, it is remarkable for the broadly oval 

 aperture, basally obtuse-angled on each side. 



Mousson thinks that the entire shell would be 38 mm. 

 long, with 10 or 12 whorls; and he mentions the possibility 

 that 0. blandi, which seems to be immature, may be a re- 

 lated form. The generic position of the species is un- 

 certain, and it is placed here merely for want of a better 

 place. Pfeiffer's figures of the type are copied on my plate. 



Subgenus PROMOUSSONIUS Pilsbry, 1906. 

 Similar to Synapterpcs, but striate and decussate, with the 

 embryonic whorls large and arcuately rib-striate. Type S. 

 incertus. 



