34 SPIRAXIS. 



variation in contour, more slender ,and stouter shells occur- 

 ring in each -colony. Thus extremes of shape in a large 

 series from Mandeville measure : 



Length 17.5, diam. 3.9, ^aperture 4 mm. ; whorls 10. 



Length 16, diam. 3.4, aperture 3.8 mm.; whorls 9%. 



Length 14.3, diam. 3.9, aperture 3.9 mm. ; whorls 8%. 



A young shell from the siame place is illustrated, fig. 29. 



After describing this species, Adams decided 'that it was 

 identical with Bulimus subula Pfr. (Opeas gmcile Hutt.), 

 and in 1851 he placed it in the synonymy of that species, a 

 course clearly erroneous. The B. impressus and B. jamai- 

 censis of Reeve are clearly synonyms of typical S. procerus. 

 B. nitidiusculus of Adams is described below and figured 

 from the unique example in his 'Collection. It is absolutely 

 identical with young S. procera of equal size. 



B. nitidiusculus. PI. 3, figs. 30, 31. Shell imperforate, 

 oblong-turrite, thin, polished, with sculpture of irregular and 

 widely spaced longitudinal grooves. There are 12 or 13 

 grooves on the last whorl, about the same number on the 

 penult and the next earlier whorls, and none on the first two 

 whorls. Outlines of the spire straight, the summit very ob- 

 tuse. Whorls 4%, rather weakly convex. The apex is min- 

 ute, but the first whorl enlarges very rapidly, so that its last 

 half -appears abnormally large. Suture moderately im- 

 pressed, with a margin by transparence below. Last whorl 

 tapering below the broadly rounded periphery. Aperture 

 subvertical, piriform, the outer lip thin, arching forward in 

 profile view. Columella cord-like, concave below, strongly 

 convex and spirally entering above. Parietal callus a mere 

 film. Length 6, diam. 2.5, length of aperture 2.8 mm. 



35. S. CLAVA (Reeve). PI. 3, fig. 36. 



" Shell subulate, papillary at the apex, not umbilicated, 

 whorls ten in number, smooth, polished, here and there lon- 

 gitudinally impressly striated, sutures margined, columella 

 thin, but little reflected, aperture rather small, lip simple; 

 transparent horny. The columella of this species is ex- 

 tremely thinly reflected, and the outer lip is rather inclined 

 to be sinuated at the upper part." (Rve). 



