NO. 5 INTERMEDIATE HOSTS OF ASIATIC BLOOD FLUKE BARTSCH 39 



early postnuclear whorls are marked by incremental lines and gradu- 

 ally developing axial ribs which vary materially in strength and 

 spacing in the various species. These ribs extend over the periphery 

 and base but become enfeebled toward the umbilicus. The spaces 

 between the ribs, as well as the axial ribs themselves, are marked by 

 slender threadlike incremental lines which also vary decidedly in 

 strength. In addition to this, these incremental lines in some of the 

 species are flexed at more or less regular intervals, which tends to 

 give them a spiral sculpture effect. In mature shells a strong varix 

 is present a little behind the edge of the peristome of the outer and 

 basal lip, which in some of its species decidedly thickens even the 

 base of the columella. Suture strongly impressed. Periphery rounded. 

 Base narrowly umbilicated. Aperture somewhat oblique, varying 

 from oval to subquadrate. Peristome thin, expanded and reflected, 

 adnate to the preceding whorl at the parietal wall. 



Operculum. — The operculum is thin, corneous, paucispiral, having 

 2.2 whorls, with very excentric nucleus. The operculum in number 

 of whorls therefore agrees with Blanfordia, but is much smaller and 

 with more excentric nucleus. 



Radula. — The radula of the various species of Oncoinclania show 

 no diversions in the rachidian or lateral teeth. The rachidian tooth 

 has 3 denticles on the free edge, of which the central is the larger. 



It also has two pairs of basals ; its formula, therefore, is . In this 



respect it stands between Katayama, which has the formula 



i-i-i 



2-1-2 



and Schisfosoiuopliora. which has the formula . The lateral 



2-2 



tooth is very oblique and bears 6 denticles, of which the third from 



the inside is by far the largest. This may be designated as 2-1-3, 



in which respect it agrees with Katayauui, but not S chistosomophora, 



which has 3-1-3. It is in the inner marginal that we find considerable 



variation. One group has 9, a second 7, and another 6 denticles. The 



outer marginal bears 5 denticles, of which the inner is larger than 



the rest, in which character it agrees with both Katayama and 



S chistosomophora. 



Animal. — The animal of Oncomclania schuiackcri was figured by 

 Heude (8), plate 33, figures 1-7. Li (46) also based his splendid 

 anatomic and embryologic studies on this species. 



I have not seen living specimens and would have to quote from 

 these sources : I prefer to refer students to Dr. Li's careful and 



