THE NAUTILUS. 129 



lots, of 13 and 5 specimens respectively. 1 In one lot the shells are 

 more conic than the types, with the rib-striae more delicate and 

 sharp, obsolete on the base. Specimens measure: 



Length 10. f>, diam. 5 mm.; 9^ whorls. 



Length 10, diam. 5 mm.; 9 whorls. 



Length 9, diam. 4.2 mm.; 9 whorls. 



In the other lot the shells are larger but also sculptured with deli- 

 cate, thin rib-stria?, much narrower than their intervals. Length 13, 

 diam. G mm., 10 whorls. This race may be called var. tenuistriuta 

 (pi. VIII, flg. 14). 



MlCROCERAMUS PEUCONICUS TRINIDADENSIS, n. var. PI. VIII, 



figs. 15, 17, 18. 



The shell is imperforate. the last two whorls forming a broad, 

 shortly cylindric part, those above rapidly tapering in form of a 

 straight-pointed cone, slender above ; rather glossy ; corneous-brown, 

 the last 4 or 5 whorls nearly covered with patches on which the 

 stria} are opaque white. Whorls convex, the earlier ones more 

 strongly so. Sculpture of regular, closely set, retractive stria?, as 

 wide as their intervals, every second or third one a little enlarged at 

 the upper end, forming an irregular series of svlsutural pnpilla. 

 The last whorl is rounded, or there may bean inconspicuous very 

 low cord upon which the stria? enlarge, defining the base. The 

 aperture is oblique ; peristome scarcely expanding, slightly thickened 

 and white within, the interior elsewhere light brown. Columella 

 vertical, straight, projecting forward a trifle near Ihe insertion, the 

 margin dilated above and adnate, not built forward. 



Length 7.3, diam. above aperture 3.2, including aperture 3.75 

 mm.; whorls 8|. 



Length 7.7, diam. including aperture 3.9 mm.; 9 whorls. 



Length 5.8, diam. including aperture 3.2 mm.; 8 whorls. 



West side of " La Vigia," Trinidad, under stones, etc. Also on 

 the northwest side. 



M. percnnicus trinidadeJisis stands near M. angahsvs (" Gundl.," 

 Pfr.) which it resembh s in sculpture and in the structure of the 

 columella, but it differs by the much more obese shape constant in a 

 large number collected, and by the stronger sutural denticulation. 



'Most of tlie small shells I got at Zaza del Medio were lost through an acci- 

 dent. These two lots were saved by being in bottles carried in my pockets. 



