THE CYCI.O'PH0RiID LA]S"D MOLLUSCS OF AMERI'CiA 161 



smooth. Wliorls 5, flattened near the suture, marked above by 

 rounded plicate corrugations and rounded narrow spiral lirations. 

 The last whorl is obtusely angailated at the periphery, smooth about 

 the umbilicus. Aperture obliquely circular; peristome simple, pro- 

 foundly sinuated at the suture. Operculum corneous with closely 

 spaced whorls which are ragged at the periphery. Height, 20 mm. ; 

 greater diameter, 32 mm. ; lesser diameter, 25 mm. 



The type came from Cachabi, Ecuador. 



The above is a translation of Da Costa's description. He adds: 

 "A very interesting shell, distinguished from any other species of 

 this genus, in that it has at the juncture of the aperture and the 

 last whorl a deep sinuation, similar in character to that of Ptero- 

 cyclos; the upper surface of the shell resembles that of C. Vesconesi, 

 also from Ecuador, and described by M. Jousseaume in Le Natural- 

 iste for November 1897 but it differs in the form of the umbilicus 

 as well as in the sinuation which forms a peculiar feature in the new 

 species. I have much pleasure in naming it after Mr. Eosenberg, 

 its discoverer." 



We have not seen specimens of this species. Da Costa's figure 

 shows the aperture drawn out to form a decided auricle at the poste- 

 rior angle, in which respect it resembles C. esmeraldense (Miller), 

 from which its much smaller size will at once distinguish it. 



CALAPEROSTOMA GUAYAQUILENSE (Sowerby) 



Plate 20, Figuke 19 



1850. Cyclostoma guayaquilcnse Soweeby, Thesaurus conchyliorum, vol. 1, 

 Suppl., p. 163*, pi. 31B, fig. 219. 



1852. Cyclophorus guayaquilensis Pfehter, Monographia pneumonopomorum 

 viventium, vol. 1, p. 95. 



1861. Cyclophorus guayaquilensis Reexe, Conchologia iconica, vol. 13, sp. 79. 



1897. Amphicyclotus guayaquilensis Kobelt and Moixendorff, Nachrb, deutschen 

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



1912. Amphicyclotus guayaquilensis Kobelt, Martini-Chemnitz Conchlien Cabi- 

 net, vol. 1, sect. 19, p. 931, pi. 42, figs. 21-22. 



"Shell depressedly subglobose, of a dull fulvous colour, with brown 

 spiral lines; spire slightly acuminated, short, with a rather obtuse 

 rufous apex; volutions four, rounded; suture distinct; aperture cir- 

 cular; peritreme thin; umbilicus large, smooth, only marked with 

 extremely slender lines of growth. Guayaquil." 



This is a small species with very strong spiral keels, of which 

 Sowerby's figure shows 3 between the summit and periphery on the 

 last whorl. 



We have not seen specimens of it. 



