COCHLOSTYLA OF MINDORO PROVINCE 531 



The postnuclear whorls are rather high between summit and suture, 

 appressed at the summit, very slightly rounded, and marked by re- 

 tractively slanting incremental lines, which are almost threads and 

 which are of varying width. In addition the postnuclear whorls are 

 marked on both spire and base by fine spiral striatums and the usual 

 crisscross sculpture. The suture is moderately constricted. The 

 periphery is obsoletely angulated. There is no dark zone differen- 

 tiating the base from the spire. The base is produced, well rounded; 

 aperture oval; the outer lip broadly expanded and reflected. The 

 columella is likewise rather broadly expanded at its insertion and re- 

 flected to leave only a narrow umbilical chink. 



The type (U.S.N.M. no. 313718), collected by Mr. de Mesa at 

 Binuangan, Municipality of Paluan, northwest Mindoro, has 6.4 

 whorls and measures: Length, 61.7 mm; greater diameter, 29.8 mm; 

 lesser diameter, 24.6 mm. 



Two topotypes (U.S.N.M. no. 313719) from the same source yield 

 the following measurements: 6.2 and 5 whorls; length, 60.2 and 55.2 

 mm; greater diameter, 29.7 and 26.2 mm; lesser diameter, 24.5 and 

 21.8 mm, respectively. 



This subspecies is readily distinguished from the others by having 

 the ground color blackish brown, therefore much darker than the 

 other two subspecies. Also, the hydrophanous clouding is lighter and 

 much more pronounced. 



COCHLOSTYLA (CHRYSALLIS) PERTURBATOR Bartsch 



Plate 114, Figure 4 



1932. Cochlostyla (Chrysallis) perturbator Bartsch, Journ. Washington Acad. 



Sci., vol. 22, p. 343. 



1933. Helicostyla (Chrysallis) mindoroensis ilogana Clench and Archer, Papers 



Michigan Acad. Sci., Arts, Letters, vol. 17, p. 545, pi. 58, fig. 4 (not ilogana 

 Bartsch, 1932). 



The shell is of medium size, ovate. The early nuclear whorls are 

 white; the later and the early postnuclear whorls are buff with a 

 slender brownish line near the summit. The next to the last whorl is 

 pale chestnut-color, while the last one has almost a blackish-brown 

 ground color. The postnuclear whorls are covered with a moderately 

 thick periostracum, which is crossed by hydrophanous bands, cloud- 

 ings, or figurations of olivaceous-buff between which the ground 

 color shines through. On the last turn in most of our specimens the 

 hydrophanous portion is almost complete. The interior of the aper- 

 ture is pale blue. The expanded peristome is chocolate-brown with 

 an iridescent flush. This is also the color of the outer portion of the 

 expanded inner lip, the inner portion coinciding with the color scheme 

 of the interior of the aperture. Nuclear whorls 3.2, the first smooth, 



