154 BULLETM 181, UNTTEiD SITATE© NlATTIOiNlAIL MUSlEtUM 



terior half they are obsolete. On the ventral surface 7 fine spiral lines 

 are present between the two cords and 12 on the anterior third of the 

 rest of the whorls, while posterior to this the spiral sculpture is 

 obsolete. Suture well impressed, showing the spiral cord. Aperture 

 almost circular, slightly compressed dorsoventrally ; peristome simple. 



The specimen described and figured, U.S.N.M. No. 414156, was 

 collected by H. Daniel at Jerico, Antioquia, Colombia. It has 4.4 

 whorls and measures: Height, 7.5 mm.; greater diameter, 23 mm.; 

 lesser diameter, 17 mm. 



The weaker keels and the two strong color bands readily distinguish 

 this species from B. martinezi (Hidalgo). 



LAGOCYCLUS, new genus 



Amphicyclotine shells of helicoid shape, with spiral striations or 

 lirations. There is a notch in the peristome at the junction of the 

 inner and basal lip, which becomes bridged over behind the peristome 

 to form a conspicuous keel extending over all the whorls. 



Type: Lagocyclus crosseantos (Hidalgo). 



Distribution : Ecuador and Peru. 



KEY TO THE SPECIES OF LAGOCYCLUS 



Strong spiral threads present on last whorl. 

 Subperipheral spiral threads present. 



Spiral cords strong and regular antoni 



Spiral cords weak and irregular haematommus 



Subperipheral spiral threads absent crosseanus 



Strong spiral threads absent on last whorl. 



Shell large, greater diameter 30.6 mm vasconesi 



Shell smaller, greater diameter 21.0 mm bartletti 



LAGOCYCLUS ANTONI (Cousin) 



Plate 20, Figures 6-8 



1887. CyclopJiorus antonii Cousin, Bull. Soc. Zool. France, 1887, p. 85, pi. 4, fig. 4. 



Shell rather small, covered with an olivaceous epidermis ; when this 

 is denuded the shell is soiled white on the last turn, the rest of the 

 turns being rosy red. The nucleus consists of about one turn, which is 

 smooth. The postnuclear whorls are marked by spiral cords of which 

 7 are present on the next to the last whorl and 8 on the last. On 

 this there is also a finer thread between the heavier cords. In addi- 

 tion to this, the spire is marked by fine incremental lines. Suture 

 moderately impressed. Periphery rounded. Base somewhat inflated, 

 well rounded, and marked with 3 spiral cords equaling those of the 

 spire immediately below the periphery, and a broad heavy keel mark- 

 ing the outer edge of the umbilicus. The arched space between this 



