302 PROCEEDINGS OF THE NATIONAL. MUSEUM Vol.89 



ANNULARIA (ANNULABOPS) PERPLEXA. new species 



Plate 30, Figure 4 



Shell small, broadly ovate, straw colored. Nuclear whorls decollat- 

 ed in all oiir specimens. Postnuclear whorls very strongly inflated 

 and rounded, marked by retractively curved, sublamellar axial ribs, 

 which are stronger near the summit, where there is a slight inclination 

 toward the formation of tufts by the projection of some of these 

 riblets a little above an interval of shorter ones. Of these axial ribs, 

 65 occur on the first, and 159 on the last of the remaining turns. 

 These riblets are a little narrower than the spaces that separate them. 

 The spiral sculpture consists of rather broad, low, feebly developed 

 cords, of which 6 are present between the summit and the suture on 

 the last turn. The junction of the axial ribs and spiral cords produces 

 thickenings and slight projections which are directed backward. 

 Suture strongly constricted. Periphery inflated, strongly rounded. 

 Base short, inflated, strongly rounded, and marked by the continua- 

 tion of the axial ribs, which pass into the open umbilicus, and by 5 

 spiral cords of the same strength as those on the spire and which pro- 

 duce the same effect in their junction with the axial riblets. On the 

 umbilical wall there are at least 6 additional spiral threads of about 

 the same strength. Aperture circular; peristome double, the inner 

 slightly exserted; the outer broadly expanded, tending toward the 

 formation of a sUght auricle at the posterior angle and a little wider 

 on the posterior half of the inner lip, where it is almost flat without 

 plication or infolding. Operculum typically annularid. 



The type, U.S.N.M. No. 535682, comes from the Sierra del Abra. 

 It has 3.2 whorls remaining and measures: Length, 8.0 mm.; greater 

 diameter, 5.6 mm.; lesser diameter, 4.7 mm. 



This species is distinguished from the other Annularops by the 

 flat inner lip of the outer peristome. 



Annularodella, new subgenus 



Shell elongate-ovate, openly umbilicated, marked by regular, 

 non-articulate axial ribs on the spire, to which are added spiral 

 threads on the umbilical wall. There is a puncture at the posterior 

 angle of the aperture, which communicates directly with the exterior 

 without a siphon. 



Type: Annularia {Annularodella) morenoi, new species. 



This group resembles the subgenus Annularodes, but lacks the 

 siphon of that subgenus. 



