LAND SHELLS OF GENUS OBBA FROM MINDORO 353 



Lubang. Six are recorded as U.S.N.M. No. 195646, of which the 

 specimen figured has 5 whorls, and measures: Height, 11 mm; 

 greater diameter, 24.5 mm; lesser diameter, 19.6 mm. The scalari- 

 form specimen that we have figured has 4.9 whorls, and measures: 

 Height, 8.4 mm; greater diameter, 19.8 mm; lesser diameter, 16.1 mm. 

 The remaining 12 specimens yield measurements as given in the 

 table on the opposite page. 



This subspecies, owing to its great variation in size and its peculiar 

 scalariform tendencies, of which indications are shown even in speci- 

 mens that do not have an elevated or scalariform spire, is readily 

 differentiated from ail the others. The scalariform variations were 

 noted by von Mollendorff as cited, under the name of suhscalaris, and 

 Elera probably had the same in mind when he used the name scalaris. 



OBBA LISTERI CALOOCANA, new subspecies 



Plate 90, Figure 1 



The shell is small, depressed-helicoid, almost lenticular, with an 

 acute angle at the periphery. The nuclear whorls are pale brown; 

 the succeeding whorls flesh-colored, spotted with blotches and 

 streaks of brown, of which one series forms a median interrupted 

 band and a second less conspicuous spiral zone between this and the 

 summit. The base is pale yellowish with a conspicuous interrupted 

 spiral band about one-third of the distance between the periphery 

 and the umbilicus anterior to the periphery. The early postnuclear 

 whorls are acutely keeled, and the summit of the succeeding turns 

 falls immediately below the periphery. They are marked by mod- 

 erately strong, retractively curved incremental lines and rather 

 conspicuous incised spiral lines. Likewise are they marked by in- 

 conspicuous malleations on the anterior half. These malleations are 

 not present on the last half of the last turn, but they are present 

 immediately below the periphery on the base, although here also but 

 weakly expressed. The fine crisscross sculpture is present on both 

 spire and base, and is best shown immediately behind the aperture. 

 The base is marked by the continuation of the axial riblets and 

 moderately strong incised spiral lines. The aperture is oval; the 

 peristome is strong, thickened, and reflected, covering about one- 

 third of the umbilicus. 



Type.— The type, U.S.N.M. No. 382934, comes from Caloocan, 

 Mansalay, Mindoro. It has 4.8 whorls, and measures: Height, 11.9 

 mm; greater diameter, 27.7 mm; lesser diameter, 12.3 mm. 



Remarks. — This subspecies resembles most nearly Obba listen 

 subplanulata Mollendorff from Ambil Island. Like that it has a 

 decided peripheral angle, but not the usual extremely acute keel 

 present in Obba listen. It has the conspicuous colored banding of 



