COCHLOSTYLA OF MINDORO PROVINCE 465 



mentioned are present in mutating groups. There are before me two 

 shells from the Mindoro Province, both of which are smaller than any 

 of the other subspecies belonging to this group. These two are here 

 described. 



There has been considerable confusion in what should constitute 

 Cochlostyla calobaptus (Jonas), and the present species has by some 

 been arranged as a subspecies of calobaptus. Bulimus calobaptus was 

 originally described from Mindoro, and I am inclined to believe that 

 it is one of the mutations of Cochlostyla (Prochilus) virgata (Jay); at 

 least I seem to recognize in the figure published by Philippi in his 

 Abbildungen und Beschreibungen, etc., volume 1, plate 1, Bulimus 

 figure 6, a member of this complex. The next available specific 

 name, therefore, for the group of shells that has been called calobaptus 

 is Cochlostyla (Prochilus) cuyoensis, which I am here adopting. This 

 species ranges over parts of Mindoro and the little islands about it 

 and to the south of it and over the Busuanga group and southeastward 

 to Tablas. In some places on some of the islands it seems to be per- 

 fectly stable, while on others it seems to be mutating. Here, as 

 elsewhere, the mutations show a polyphyletic origin by having 

 different colored nuclei, which would indicate hybridization. 



KEY TO THE SUBSPECIES OF COCHLOSTYLA (PROCHILUS) CUYOENSIS IN MINDORO 



PROVINCE 



Periphery with a dark-brown band contracta 



Periphery without a dark-brown band subpalllda 



COCHLOSTYLA (PROCHILUS) CUYOENSIS CONTRACTA Mollendorff 



Plate 107, Figure 5 



1898. Cochlostyla calobapta contracta Mollendorff, Abh. Naturf. Ges. Gorlitz, 



vol. 22, p. 144. 

 1914. Cochlostyla calobapta contracta Mollendorff, Kobelt, and Winter, 



Semper's Reisen im Archipel der Philippinen, vol. 10, p. 333, pi. 72, 



figs. 13-14. 

 1914. Cochlostyla calobapta nana Mollendorff, Kobelt, and Winter, ibid., 



p. 333. 

 1932. Cochlostyla (Prochilus) cuyoensis contracta Bartsch, Journ. Washington 



Acad. Sci., vol. 22, p. 338. 



Shell very small. The nuclear whorls have a broad band immedi- 

 ately anterior to the suture, but it disappears on the postnuclear turns. 

 There is also a broad conspicuous bright chestnut-brown band at the 

 periphery and a broad area of the same color about the umbilicus. 

 The periostracum is pale straw-color and marked by protractively 

 slanting, more or less zigzag, broad hydrophanous bands. Interior of 

 aperture, peristome, and columella white. Nuclear whorls 2, strongly 

 rounded and forming a rather pointed apex. They are marked by 

 incremental lines, which are somewhat crinkled at the summit. The 

 postnuclear whorls are moderately rounded, appressed at the summit, 



1185—38 7 



