326 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



the rest pale yellowish horn colored with axial fulgurations of 

 brown. The fulgurations terminate about one-fifth of a turn behind 

 the peristome, but this area shows irregularly distributed axial 

 bands of brown of varying width. The nuclear whorls are smooth, 

 the rest marked by slender threadlike incremental lines and exceed- 

 ingly fine, almost obsolete spiral threads. The siphon is about 0.4 

 mm behind the peristome. It is curved forward and marked by 

 numerous slender annulations. Periphery well rounded, Base open, 

 forming a funnel-shaped umbilicus, showing all the turns within 

 sculptured like the upper surface, but less strongly. The tine hair- 

 like sculpture remaining in the suture of the umbilicus is short and 

 very slender. The aperture is typical. There are 10 lamellae on 

 the operculum. 



Type.— U.S.N.M. No. 3030T6, collected by Quadras at Busuanga. 

 It has 4.4 whorls, and measures: Height. 8 mm: greater diameter, 

 16.1 nun; lesser diameter, 1:2 mm. 



Remarks. — This race is very close to Opisthoporus qwadrasi p<il<i- 

 wanensis, but can be readily distinguished from it by the fulgura- 

 tions. which do not extend to the peristome, 



OPISTHOPORUS QUADRASI TURTURINGANUS, new subspeci s 



Plate si. Figure 2 



Shell small, thin, very depressed helicoid. All but the last turn 

 and a quarter chocolate-brown, the last part yellowish horn colored. 

 The first turn is well rounded, smooth, and glassy. The succeeding 

 whorls are also well rounded and are marked by closely spaced incre- 

 mental lines, which are raised into slender lines. On the upper 

 surface tine, closely spaced, incised spiral lines cut the axial thread 

 and lend the surface a silky luster. The siphon is situated about 

 4 mm behind the peristome at the suture, the tube being bent ob- 

 liquely forward or forward and downward. It is marked by numer- 

 ous incremental threads. Periphery well rounded. Base with open 

 funnel-shaped umbilicus, showing all the whorls within marked like 

 the upper surface of the shell but a little less strongly so. Here and 

 there on the whorls within the umbilicus exceedingly fine short hairs 

 are present. Aperture circular; peristome double; the inner lightly 

 exserted and very slightly reflected, the outer thin, transclucent. 

 slightly expanded on the columellar edge, a little more so on the 

 basal and outer lip and forming a moderately strong auricle at the 

 posterior angle of the aperture. Operculum with a smooth flat inner 

 plate, concave vi\^. and slightly concave outer surface. The outer 

 surface shows at least 10 closely coiled whorls with an inner smooth 

 nuclear portion. These whorls are marked by numerous obliquely 

 placed threads, which are of varying strength. 



