SOUTH AMERICAN OBELISCUS. 249 



men before me which seems referable to colunulla has a 

 smaller apex than sylvaticus, agreeing with Philippi's fig- 

 ures. It is likely that the form may stand as a variety. 



A somewhat similar shell has been figured by Deshayes in 

 Ferussac's Histoire, ii, p. 166, pi. 142 A, f. 7, 8, under the 

 name B. terebraster. 



5. 0. AGASSIZI Pilsbry, n. sp. PI. 36, fig. 76. 



Shell minutely perforate, thin, pale yellowish-corneous, the 

 later whorls plicatulate immediately under the suture but 

 elsewhere nearly smooth ; turrite-conic, the spire a trifle con- 

 tracted above. Apex subglobose. Whorls 11, convex, the 

 last two flattened, very regularly increasing, the last weakly 

 subangular at the periphery. Aperture somewhat oblique, 

 ovate ; outer lip thin ; codumella nearly straight, very slightly 

 concave, not twisted or subspiral above, its edge narrowly re- 

 flexed, the reflection long, basal margin retracted. Length 

 34, diam. 9, length of aperture 8.5 mm. ; diam. at second 

 whorl 2 mm. 



Brazil (J. G. Anthony, Agassiiz exped.). 



This is a form of the Obeliscus -group, differing from 0. 

 obeliscus and 0. carphodes by its conspicuously smaller em- 

 bryonic whorls, while 0. sylvaticus is of much more slender 

 form, with smaller aperture. The specimens were on a tray 

 with 0. sylvaticus. It probably attains a somewhat larger 

 size. 



6. 0. PATTALUS Pilsbry, n. sp. PI. 36, fig. 70. 



Shell imperforate, thin, dirty yellowish-olive, slightly shin- 

 ing, weakly striate ; turrite, the side-slopes straight, the sum- 

 mit rounded, very obtuse. Whorls 8, but slightly convex, the 

 later ones nearly flat, last whorl very indistinctly subangular 

 in front, tapering below. Aperture somewhat oblique, ovate ; 

 outer lip thin, hardly arched forward. Oolumella slightly 

 concave, dilated above, with the edge thin, reflexed and ad- 

 nate, brownish. Length 27.2, diam. 8, aperture 8.9 mm.; 

 diam. at second whorl 2.8 mm. 



Brazil (Moricand). 



