THE CYCLOPHORID LAND M0LLUSK9 OF AMEIRIOA 163 



edge of which is raggedly fringed; the elements composing it are 

 retractively striate. 



U. S. N. M. No. 250743 contains 2 specimens, received from 

 Herman Rolle, bearing the label "Chanchamayo, Peru." They have, 

 respectively, 5.4 and 5.2 whorls, and measure : Height, 15.5 and 15.3 

 mm.; greater diameter, 27.0 and 24.0 mm.; lesser diameter, 21.3 

 and 18.3 mm., respectively. 



This species appears nearest related to C. hourcieri (Pfeiffer), 

 from which it can be readily distinguished by its much coarser 

 sculpture and larger size. 



CALAPEROSTOMA BOURCIERI (Pfeiffer) 



Plate 21, Figures 1-3 



1852. Cyclostoma (Cyclophorus) hourcieri Pfeiffer, Proc. Zool. Soc. London, 

 1852, p. 151. 



1852. Cyclophorus hourcieri Pfeiffee, Monographia pneumonopomorum viven- 



tium, vol. 1, p. 95. 



1853. Cyclostoma hourcieri Pfeiffer, Martini-Chemnitz Conchylien Cabinet, 



vol. 1, sect. 19, p. 243, pi. 32, figs. 5-7. 

 1861. Cyclophorus hourcieri Reeve, Conchologia iconica, vol. 13, sp. 74. 

 1897. Amphicyclotus hourcieri Kobelt and Moixendokff, Nachrb. deutschen 

 malak. Ges., vol. 29, p. 139. 



Shell small, depressed-helicoid, pale chestnut-brown, a little darker 

 on the spiral threads and some of the axial ribs. The extreme apex 

 has a faint reddish tinge. The nucleus consists of about one smooth 

 turn; the succeeding turns are marked by low, rounded, rather broad 

 spiral threads, of which 8 are present between the summit and the 

 periphery. These spiral threads are less strong near the summit 

 and gradually increase in strength toward the periphery. The axial 

 sculpture consists of strong incremental lines, which assume almost 

 the strength of riblets. Suture strongly impressed, almost channeled. 

 Periphery well rounded. Base somewhat inflated, strongly rounded, 

 and marked by the continuation of the incremental lines which here 

 are a little less strong than on the spire and spiral threads which are 

 quite feeble and absent on the umbilical wall. The umbilicus equals 

 about one-third of the diameter of the shell. Aperture decidedly 

 oblique, slightly protracted at the posterior angle; peristome simple, 

 Avith a strong callus covering the parietal wall. Operculum with 

 central nucleus, concave on the outside and convex on the inside, 

 with a slender knob on the center of the inside. The outside shows 

 about 10 whorls, the outer edge of which is slightly fringed. 



U.S.N.M. No. 307411 contains 2 specimens from Quito, Ecuador. 

 They are of about the same size ; the one figured has 4.5 whorls and 

 measures: Height, 11.9 mm.; greater diameter, 18.5 mm.; lesser diam- 

 eter, 14.3 mm. 



