THE PHILIPPINE POND SNAILS OF THE GENUS VIVIPARA. 



By Paul Bartsch, 



Assista7it Cnrator, Dkismi of 3Iollu»ks, U. S. National Museum. 



In the present paper all of the species of this genus heretofore known 

 from the Philippine Islands have been considered, as well as a host of 

 new forms which were collected by Maj. Edgar A. Mearns, U. S. Arm}', 

 and presented by him to the U. S. National Museum. 



VIVIPARA ANGULARIS Miiller. 

 Plate X, fis- 1. 

 Helix anr/iiIarls'Mvi.i.KR, Hipt. Verm., Pt. 2, 1774, p. 187. 



Shell quite large, conic, light to dark olive green. Whorls increas- 

 ing very regularly in size. The iirst and second rather loosely coiled, 

 marked b}' faint spiral lirations. On the third the keels characteristic 

 of the adult shell make their appearance; in addition to the keels there 

 are many fine spiral lirations. The adult shell is marked by three 

 spiral keels between the sutures, of which the peripheral one is b}' 

 far the strongest. The two supra-peripheral keels divide the space 

 between the sutures into three areas, of which the one immediately 

 below the summit is a little wider than the other two, which are equal 

 in width. The space between the summit and the first keel forms a 

 sloping shoulder. In addition to the three keels, the whorls are marked 

 by numerous microscopic, minutel}' granulose spiral lirations and 

 moderately strong incremental lines between the sutures. Periphery 

 of the last whorl angulated. Base well arched, narrowly umbilicated, 

 marked ])y lines of growth and many fine, wavy, equally developed, 

 and equally spaced finely wrinkled spiral lirations. In some specimens 

 the area adjoining the umbilicus is moderateh' excavated, in others it 

 is almost closed. Aperture suboval, bluish white within, edged with 

 a dark-brown border; outer lip thin, rendered slightly sinuous by the 

 keels; columella moderately strong, concave, and slightly reflected; 

 parietal wall covered with a thick callus in adult shells, which is bluish 

 white, with a dark border, and lends the peritreme a complete aspect. 



Proceedings U. S. National Museum, Vol. XXXII— No. 1518. 



135 



