LAND SHELLS OF GENUS OBBA FROM MINDORO 



357 



The species is named for Pedro de Mesa, whose fine sending of the 

 typical races stimulated the present revision. 



KEY TO SUBSPECIES OF OBBA MESAI 



Crisscross lines rather strongly developed on upper surface. 



Crisscross sculpture on lower surface strong sablayana. 



Crisscross sculpture on lower surface obsolete richi. 



Crisscross lines feebly developed on upper surface. 



Spiral striations strong m9sai. 



Spiral striations obsolete Johnson i . 



OBBA MESAI SABLAYANA, new subspecies 



Plate 91, Figure 3 



The early whorls are of flesh-colored ground color; the later ones are 

 straw-colored, as is also the base. The interrupted dark zones and 

 mottlings occupy the major portion of the upper surface of the shell, 

 and are dark chestnut-brown; brighter on the early turns. The 

 peristome is soiled pale buff. Crisscross sculpture strongly developed 

 on both the upper and lower surfaces. The spiral striations are almost 

 obsolete on the upper surface of the last half of the last whorl and only 

 feebly expressed on the lower surface. 



Type.— The type, U.S.N.M. No. 382697, was collected on the 

 United States Bureau of Fisheries Albatross Expedition on Sablayan 

 River, southern Mindoro. It has 5 whorls, and measures: Height, 

 14.9 mm; greater diameter, 32.7 mm; lesser diameter, 25.1 mm. 



Remarks.— Ten topotypes, U.S.N.M. No. 296929, yield the following 

 measurements : 



This subspecies belongs to the strongly crisscross sculptured group 

 of Obba mesai, which character it shares with 0. m. richi, but in richi 

 the crisscross sculpture is obsolete on the base, while in the present 

 subspecies it is strongly developed there. 

 150038—33 2 



