148 BULLETIN ISl, UNITED STATES Nu^TIOOSTlAiL MUSEUM 



There appears to have been considerable misunderstanding about 

 this species. We have lumped v. Martens' Megalomastoma {Tomo- 

 cyclus) simulac7^7n Tninus and his M. (T.) simulacrum' gracilius 

 under this name, which we feel justified in doing from the specimens 

 before us. The small size will readily differentiate this from the 

 other more or less smooth forms. 



Subfamily Diplommatininae Kobelt 



This subfamily embraces a dozen or more genera and some 400 

 species. Its distribution extends from Siberia south through India, 

 and in the west Pacific Island complex from Japan to eastern New 

 Zealand. Only a single genus, Adelopoma^ has been reported from 

 America. 



Genus ADELOPOMA Doering 



1884. Adeloponia Doering, Bol. Acad. Nac. Cienc. Cordoba, vol. 7, p. 457. 



1898. Eupalaina Kosfxt and Moixendoeff, Nachrb. deutschen malak. Ges., vol. 



30, p. 131, in part. 

 1898. Cylindropalaina Kobelt and Moixeindorff, ihid., p. 133, in part. 



Small pupiform, sinistral or dextral shells, white, thin. Nuclear 

 whorls smooth ; postnuclear whorls ornamented with scalarif orm axial 

 ribs; suture strongly constricted. Aperture circular, with a small 

 denticle on the columellar wall ; peristome double. Operculum thin, 

 corneous, with 3 or 4 whorls whose outer edge is slightly upturned. 



Type : Adelopoma tucma Doering. 



Distribution : Costa Rica to Peru. 



The radula formula cited by Doering is : 5:4:4:2 for A. tucma. 

 Baker (Occ. Pap. Mus. Zool. Univ. Michigan, No. 137, p. 47, 1922) 

 gives the radula for A. occidentale Baker from La Fria, Venezuela, 

 as 7 : 5 : 5 : 5. This is our A. hakeri. 



In 1863 Philippi described Pupa limensis (Malak. Blatter, vol. 14, 

 p. 75), and this was later referred by Doering and Ancey to the genus 

 Adelopoma, but Pilsbry has definitely shown that it belongs to the 

 genus Pupoides in the Pupillidae. 



ADELOPOMA TUCMA Doering 



Plate 40, Figure 1 



1884. Adelopoma tucma Doering, Bol. Acad. Nac. Cienc. Cordoba, vol. 7, p. 458, 



figs. 

 1902. Adelopoma tucma Kobelt, Das Tierreich, Cyclophoridae, p. 480. 



We have not seen this species, but we give a translation of Doering's 

 description and copy his figure. 



Shell rimate, small, oblong-ovate, pupilliform, thin, white, crystal- 

 line, with attenuated apex, closely obliquely rib-striate; whorls 6, 

 convex, the first 2 nuclear, smooth. The postnuclear whorls are ele- 



