310 PROCEEDINGS OF THE NATIONAL MUSEUM Vol.89 



decollated in all our specimens. Postnuclear whorls rather high be- 

 tween summit and suture, marked by decidedly retractively slanting, 

 slender, sublamellar axial riblets, of which 115 are present on the last 

 turn. These riblets are only about one-fourth as wide as the spaces 

 that separate them. They become slightly intensified and a trifle 

 expanded at the summit. Suture well constricted. Periphery well 

 rounded. Base moderately long, well rounded, openly umbilicated. 

 The umbilical wall is marked by the continuation of the axial riblets 

 and by weakly developed spiral tlireads, which extend up on the ante- 

 rior half of the base. Last whorl solute for about one-eighth of a turn. 

 Aperture broadly oval; peristome double, the inner decidedly exserted 

 and slightly reflected, forming a slender notch at the posterior angle, 

 where it is backward deflected, suggesting a siphon. The outer peri- 

 stome is rather broadly expanded and reflected and it is likewise bent 

 backward at the posterior angle. Operculum typically fossularid. 



The type, U.S.N.M. No. 493488, comes from Boquer6n del Jati- 

 bonico, Santa Clara Province. It has almost 5 whorls remaining and 

 measures: Length, 18.7 mm.; greater diameter, 10.3 mm.; lesser 

 diameter, 8.3 mm. 



Subgenus Eutudorisca Henderson and Bartsch 



1920. Eutudorisca Henderson and Baktsch, Proc. U. S. Nat. Mus., vol. 58, p. 78. 

 1920. Eutudorella Henderson and Bartsch, Proc. U. S. Nat. Mus., vol. 58, p. 78. 



Shell almost turbinate in form, spiral cords much stronger than the 

 axial sculpture, which is decidedly reduced, almost obsolete. A notch 

 in the parietal callus near its junction with the outer lip leaves a 

 breathing space here, when the animal is withdrawn. Operculum 

 with the lamella reflected outward to parallel the chondroid basal 

 plate, but falling short of reaching the outer edge of the whorls, thus 

 leaving a zone of the chondroid plate showing in each turn. 



Type: Annularia (Eutudorisca) jimenoi ([Arango] PfeifFer). 



We now believe that there is not sufficient distinction between 

 Eutudorisca and Eutudorella for subgeneric designation, and we there- 

 fore merge the second name under the first. 



KEY TO THE SPECIES OP THE SUBGENUS EUTUDORISCA 



Peristome broadly expanded jimenoi 



Peristome not broadly expanded. 



Notch at the posterior angle of aperture scarcely perceptible.- camoensis 

 Notch at the posterior angle of aperture well developed. 



Shell broadly conic agassizi 



Shell broadly ovate catenata 



