COCHLOSTYLA OF MINDORO PROVINCE 419 



1895. Helicostyla orbitula Pilsbry, Man. Conch., ser. 2, vol. 9, p. 225. 



1896. Cochlostyla orbitula Elera, Catalogo sistematico de toda la fauna de 



Filipinas, vol. 3, p. 585. 



1897. Cochlostyla orbitula Hidalgo, Journ. Conchyl., vol. 44, pp. 260, 331, 335, 



341, 351. 



1898. Cochlostyla orbitula M Ollendorff, Abh. Naturf. Ges. Gorlitz, vol. 22, 



p. 131. 

 1901. Cochlostyla orbitulus Hidalgo, Obras malacologicas, p. 459, pi. 38, figs. 



6, 7; pi. 95, fig. 2. 

 1910. Cochlostyla orbitula Mollendorff, Kobelt, and Winter, Semper's Reisen 



im Archipel der Philippinen, vol. 10, pp. 149-150, pi. 51, figs. 5, 5a. 

 1932. Cochlostyla (Chochlodryas) orbitula Bartsch, Journ. Washington Acad. Sci., 



vol. 22, p. 337. 



Shell subglobular, covered with a thin periostracum that seems to 

 partake of the general color scheme characterizing the particular part 

 of the shell covered. The coloration of the nuclear whorls consists of 

 a white area covering the posterior half of the turns and a pale chest- 

 nut-brown area covering the rest of the exposed portion. Beginning 

 with the postnuclear whorl, there is a rather broad, conspicuous, 

 chestnut-brown band, which rapidly increases in intensity of colora- 

 tion to chocolate-brown. This band occupies the middle of the ex- 

 posed portion of all the turns. On the succeeding turns a pale green 

 band appears halfway between the brown band and the summit. 

 This band gradually widens until it extends to the median band of 

 brown, leaving a big broad zone of white at the summit. A second 

 green band appears immediately above the summit of the succeeding 

 turn, and this also gradually widens posteriorly until it reaches the 

 median brown band. Both the posterior and the anterior green 

 bands become diluted as they approach the median band, the deepest 

 shade of green being at the posterior extremity of the green band in 

 the posterior zone and the peripheral extremity in the anterior band. 

 The base is of an orange-brown color, paler within the aperture. 

 There is a broad brown band a little wider and of a little darker shade 

 than the median one of the spire, and this band is separated from the 

 green zone at the periphery by a narrow zone of the ground color of 

 the base. The columellar area is surrounded by a chocolate-brown band. 

 The interior of the aperture, the outer lip, and the columella are white, 

 the dark bands showing within the aperture. Nuclear whorls almost 2, 

 well rounded, marked by incremental lines and on the last portion of 

 the last turn by fine spiral striations. The postnuclear whorls are 

 appressed at the summit, strongly rounded and marked by retractively 

 slanting lines of growth and microscopic spiral striations on both spire 

 and base. The periphery, although well rounded, gives one the 

 impression of being obsoletely angulated, probably because of the 

 color pattern. The base is short, inflated, and well roimded. The 

 aperture is broadly oval and oblique, the outer lip being decidedly 

 expanded and reflected. The columella is slightly excavated. 



