﻿110 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 102 



Family TROGLOTREMATIDAE 



4. PARAGONIMUS WESTERMANI Kerbert, 1878. 



Geographical distribution. — In the Orient, Japan, Korea, Man- 

 churia, Formosa, China (especially Chekiang Province) , French Indo- 

 China, the Philippine Islands, Siam, the Malay Peninsula, Assam, 

 India, New Guinea, Java, and Sumatra. Also South xVmerica, prob- 

 ably Africa, and one record for North America. 



Intermediate snail hosts. — Thiara granifera (Lamarck) (Formosa) , 

 Thiara {Melanoides) tuberculata ^vll&r (Formosa.), Semisulcospira 

 lihertina Gould (Formosa and Japan) , Hua species, and Syncera lutea 

 A. Adams (China). Unknown elsewhere. 



Second intermediate hosts. — The fresh-water crabs Potairwn {Geo- 

 thelphusa) ohtusipes Stimpson, P. dehaanii White, and Eriocheir 

 japonicus De Haan. 



Definitive hosts. — Lungs of mammals, especially the felines and man. 



The life cycle was first elucidated by K. Nakagawa in Formosa in 

 1917. 



"When the snails are placed in water containing miracidia, the 

 latter swarm around them and become attached to the heads, jaws and 

 feet, but rarely to the tentacles and mantles. They cling with their 

 suckers, insert proboscis into the tissue of the host and enter the body 

 of the snail like the cercariae of Schist osomum [sic] japonicum, as de- 

 scribed by Miyairi (1915). Unlike the miracidia of Schistosomum, 

 those of the pulmonary distoma Paragonimus shed their cilia in this 

 act. 



"Besides the cercariae, sporocysts of various sizes are found abun- 

 dantly in the liver of Melania [ + Thiara and Semisulcospira']. They 

 are sometimes found in the heart and kidneys." (Nakagawa, 1917, 

 pp. 301-302). 



Remarks on snail host specificitt. — Gastropod mollusks serve as 

 the obligatory first intermediate host of all digenetic trematodes or 

 flukes. While in several cases the relationship between the parasitic 

 fluke and the host snail is restricted to one species in certain areas, on 

 the whole there does not appear to be any set pattern for certain snails 

 to serve as hosts to any particular spe'^ies or even genus of trematode. 



Of the three important blood flukes that infect man, Schistosoma 

 japonicum appears most restricted in its choice of only one genus 

 of snails, Oncomelania. In the Philippine Islands, Oncomelania 

 quadrasi Moellendorff is the only known carrier; in Japan, only 0. 

 nosophora Robson. This genus of snails is a gill -breathing amni- 

 colid. Yet Schistosoma mansoni Sambon and S. haematohium Bil- 

 harz, of Africa and tropical America, are carried by the snails Bulinus, 

 Physopsis, and AKstralorhis, all of which are lung-breathing Planor- 



