ANTILLEAN OBELISCUS. 267 



opaque. The specimen figured (pi. 30, fig. 18) measures, 

 length 24, diam. 4,1, aperture 4.8 mm., with ll 1 /^ whorls. 



24. 0. HENDERSONI Pilsbry, n. sip. PI. 32, fig. 17. 



Shell imperforate, thin, pale yellow, the earlier whorls 

 sometimes corneous-whitish ; glossy, weakly striate, the stria 

 straight and slightly oblique. The spire tapers straightly to 

 the obtuse summit. Whorls 8% to 8%, all very convex, reg- 

 ularly increasing, first 1% whorls regularly, finely cren- 

 ulate at the suture; subsequent whorls joined by a well- 

 impressed but nearly even suture. Last whorl -convex below. 

 The aperture is small, slightly oblique, irregularly ovate; 

 outer lip thin, not sinuous. Columel'la vertical, straightened 

 and refiexed above, very indistinctly subtruncate before 

 reaching the base. Length 13.7, diam. 3.7, aperture 3 mm. ; 

 diam. at second whorl 1.1 mm. 



Haiti : Sans Souci, near Cape Haitian, (type lO'C. ; Port au 

 Prince (Henderson and Simpson). 



By its rounded whorls, like Subulina octona, this differs 

 from all Antillean Obelisci except the following species. The 

 crenulate suture of the embryonic whorls is a further distin- 

 guishing feature. Named for John B. Henderson, Jr. 



25. 0. SIMPSONI Pilsbry, n. sp. PI. 32, fig. 18. 



Shell imperforate, thin, corneous with a very thin pale 

 yellowish cuticle, subtranslucent, finely striate, the striae a 

 little arcuate. The spire tapers straightly to the very small 

 obtuse apex. Whorls 10, all quite convex and joined by a 

 deeply impressed suture. Aperture small, somewhat oblique, 

 ovate ; the outer lip thin, arched forward a little above. 

 Columella straight, somewhat oblique, obliquely subtruncate 

 before reaching the base. Length 11.2, diam. 3, aperture 2.9 

 mm. ; diam. at the second whorl .8 mm. 



Haiti: Port au Prince (Henderson and Simpson). 



This species, named in honor of Charles T. Simpson, closely 

 resembles the slender Haitian form of Opeas gracile called 

 octonula by AVeinland, but differs totally from that in the 

 structure of the columella; octonula being a typical Opeas, 



