UNIVERSITY 



BULIMULUS-BOSTRYX-PLATYBOSTRYX. 129 



\ 



d. Shell narrow, Melania-shaped, regu- 



larly tapering; subimperforate ; colu- 



mella subtruncate, Geopyrgus, p. 135^ 



dd. Shell narrow and elongated, convexly 



tapering, perforate, Peronceus, p. 138. 



ddd. Shell with obese body-whorl, umbili- 



cate or perforate, Lissoacme, p. 



Section 1. PL AT YBOSTRYX Pilsbry, 1896. 



Wider than high, with broad, crater-shaped umbilicus; the top- 

 flattened with mamillar apex, the last whorl acutely keeled at 

 periphery and base. 



B. EREMOTHAUMA Pilsbry, n. n. PL 44, figs. 83, 84, 85, 86. 



Shell wider than high, with a broad crater-shaped umbilicus, 

 acutely carumti-d j>< -rijilif /// mid base, low spire, and descending last 

 u'lorl. White, or with flesh-colored suffusion in places; solid but 

 thin, calcareous. Surface lusterless, rudely wrinkle-striate above, 

 the wrinkles cut and festooned by a group of spiral incised striae ; 

 the lower surface vertically, irregularly plicate, and often with some 

 short transverse wrinkles. Spire low-convex, the apex mamillar, 

 projecting, smooth. Whorls 4J, rapidly widening, the latter two 

 concave above ; last whorl with very acute, pinched peripheral and 

 basal keels ; its latter third or half deeply descending. 



Aperture white or brownish inside, subtriangular, oblique, angular 

 above, and acutely so at positions of outer and basal keels ; peri- 

 stome continuous, in contact with preceding whorl at its upper angle 

 only ; upper margin simple, outer slightly expanded, columella mar- 

 gin arcuate and expanded. 



Alt. 10, diarn. 14 mill. (type). 



Alt. 11, diam. 12 mill. (Hidalgo). 



Cachina! de la Costa (Phil.); Paposo (Phil., Paz.), Desert of 

 Atacnma, Chili, under stones and among the roots of plants. 



Helix reenteii PHIL., Anales de la Univ. de Santiago, 1855, p. 

 213; Malak. Bl.,1856, p. 52, 152; Reise durch die Wiiste Atacama, 

 1860, p. 182, pi. 7, f. 8. PFR., Monogr., iv, p. 182. HIDALGO, 

 Moluscos del Viaje al Pacifico, p. 22, pi. 1, f. 4-5. Not Bulimus 

 reentn Phil., 1851. 



Hidalgo records a form measuring, alt. 9, greater diam. 15, lesser 

 13 mill. ; spire flat, last whorl less descending, umbilicus wider, 

 peristome more adnate. 

 9 



