54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



ONCOMELANIA CRASSA (Heude) 

 Plate 6, fig. 6 



1890. Hemibia crassa Heude, Mem. Concern. Hist. Nat. Emp. Chinois, p. 169, 



fig. 18. 

 1924. Oncomelania hupcnsis Annandale, Amer. Journ. Hyg., Mon. Ser. no. 3, 



p. 285, in part. 



The collection of the United States National Museum contains no 

 specimens referable to the species described under this name, nor 

 do we have any specimens from a nearby locality u^hich might be 

 referred to it. I therefore give a free translation of Heude's de- 

 scription and republish his figure. 



This species is readily distinguished by its elongate form and the 

 obtuse spire which is rarely entire. The intercostal spaces are wide 

 and distinctly marked by incremental lines, which are also present 

 on the axial ribs. The specimen figured shows that the peristome 

 extends beyond the varix. The edge of the peristome is black, and 

 the periostracum is greenish black. He states that he found this 

 species in winter, a long time out of water, along the edges of the 

 drainage ditches which empty into Lake Tong-lieou in summer. 



REMEDIAL MEASURES 



It appears that where the Katayama, the Oncouiclania, and the 

 Schistosomophora groups are present, an acid condition of the soil 

 exists. The use of crushed limestone over such territory will change 

 that condition into an alkaline reaction and make it an inhospitable 

 habitat for these moUusks, resulting in their elimination. The absence 

 of a suitable host in a habitat will eliminate the possibility of the worm 

 developing in that region. 



REFERENCES CITED 

 (i) Adams, Arthur 



1861. On some new genera and species of Mollusca from the North of 

 China and Japan. Ann. Mag. Nat. Hist., ser. 3, vol. 8, pp. 299- 

 309- 



(2) Adams, Arthur 



1863. On a new genus of terrestrial moUusks from Japan. Ann. Mag. 

 Nat. Hist., ser. 3, vol. 12, pp. 424-425, pi. 7, figs. 11-12. 



(3) Pfeiffer, L. 



1876. Mon. Pneumon. Viv., Suppl. 3, pp. i-x, 1-479- 



(4) Nevill, Geoffroy 



1878. Hand list of Mollusca in the Indian Museum, Calcutta, pp. i-xv, 

 1-338. 



