SPIRAXIS. 29 



whorl being drawn out. The rib-stria? are arcuate, about 

 equal to the intervals, and the columella is typically rather 

 strongly twisted, but in some shells, probably constituting a 

 subspecies or local variety, the twis't is much less marked. 



This species is somewhat related to S. terebella and its 

 small form or variety conferta, of Jamaica ; but it is very 

 muich more strongly striate, the striae more arcuate, the spire 

 more slender, and 'there are more smooth apical whorls. 8. 

 melanielloides is also related to 8. rectus Pfr., of Haiti. It 

 has a superficial resemblance to the Cuban Pseudosubulina 

 exilis Pfr. 



31. S. RECTUS (Pfeiffer). Vol. I, pi. 9, fig. 31. 



Shell imperforate, srubulate, rather thin, closely subarcu- 

 ately plicatulate, a 'little glossy, waxen. Spire regularly tap- 

 ering, the apex acute; suture impressed; whorls 7, rather 

 flat, the last about one-fourth the length, rounded basally. 

 Columella very lightly folded above. Aperture sub vertical, 

 oblong, the perisltome simple, unexpended, its margins sub- 

 parallel, columella r margin somewhat calloused. Length 5, 

 diam. 1.5, aperture 1.25 num. long, scarcely .66 wide. (Pfr.) . 



Santo Domingo: Sierra Monte Cristi (Hjalmarson). 



Bulimus rectus PFR., Malak. Bl. v, p. 152, pi. 3, f. 11, 

 12, 13 (1858) ; Monogr. vi, p. 99. Volutaxis rectus STREBEL, 

 Beitrag v, p. 125, pi. 17, f. 24. TRYON, Man. Conch, i, p. 52. 



This Santo Domingan species, Strebel remarks, belongs by 

 its 'Columellar structure and sculpture to Volutaxis. The 

 shell is slenderly drawn out, and has very flatly convex, regu- 

 larly increasing whorls. The sculpture is quite like that of 

 8. confertecostatus. It measures 5.4 mm. long, with 7 whorls. 



I have not seen the shell. The type figure, copied by 

 Tryon in vol. I, is too small to show its 'characters satisfac- 

 torily. 



32. S. TEREBELLA (C. B. Adams). PL 1, figs. 8, 10, 11. 



"Shell very 'much elongated, regularly tapering to the 

 summit ; dingy white ; with numerous transverse lightly im- 

 pressed strige; spire with rectilinear outlines'; apex rather 



