﻿SNAIL HOST OF ORIENTAL LLTNG FLUKE — ABBOTT 97 



LIFE HISTORY 

 HABITAT 



As has been stated earlier, the various subspecies or geographical 

 races of Thiara granifera have not been studied adequately, so that 

 details of its geographical distribution cannot be presented at this 

 time. However, the limits of its distribution as a whole are fairly well 

 known. This species lives in fast-flowing fresh-water streams. Its 

 most westerly limits include the Island of Ceylon and the eastern coast 

 of India. Its range extends easterly to include the coasts of Siam and 

 southern China, the East Indies, and the Philippine Islands. To the 

 north it is found on Formosa, (Taiwan) Island and the small islands 

 south of Japan. Farther east, it is common in Melanesia, especially 

 the Solomon Island Archipelago, the Marianas, and the Polynesian 

 islands of the Hawaiian and the Society Islands. Undoubtedly the 

 topography and nature of the areas in which this species is found 

 varies from place to place, but it is highly likely that certain optimum 

 environmental conditions are common to all its localities. Thus we 

 may find this species in streams very near the sea in certain small 

 islands, but considerably inland and at higher altitudes on such large 

 islands as Luzon, Leyte, and Mindanao in the Philippine Islands. 



In the isolated Micronesian islands of the Marianas only three 

 islands are large enough to have permanent streams : Guam, Saipan, 

 and Rota. All three support colonies of Thiara (Plotiopsis) scahra, 

 but only the first possesses streams large enough to maintain popula- 

 tions of Thiara (Tarehia) granifera. Guam (Guajan) Island is 32 

 miles long by 4 to 10 miles wide and about 225 square miles in area. 

 It is mountainous in the southern half, where a great number of small 

 streams flow down to the sea. The northern half forms a low plateau, 

 which is devoid of permanent streams. 



The majority of the streams in the southern half of Guam are col- 

 onized by Thiara granifera. Collections were made at the localities 

 listed. The number following each station record indicates the number 

 of specimens collected (fig. 40) . 



A. Zadue Maagos River. 1945. D. Frey collector. 92. 



B. Agafia Spring, 1^^ miles southeast of Agafia. April 22, 194.5. R. T. Abbott 



collector, 198. 



C. Talisai stream, under bridge, 2 miles southeast of Agat. May 1, 1945. 



R. T. Abbott collector. 100. 



D. Water Plant, 2 miles up Ylig River. April 26, 1945. R. T. Abbott collector. 



65. Flow rapid, 6 feet wide, 6 inches deep. 



E. 1 mile up Pago River. April 26, 1945. R. T. Abbott collector. 50. Flow 



rapid, 6 feet wide, 4 inches deep. 



F. First stream 600 yards south of Piti. April 24, 1945. R. T. Abbott col- 



lector. 38. Flow sluggish, 3 feet wide, 1 inch deep; shady. 



G. Geus River. 1945. D. Frey collector. 97. 



H. 100 yards up Aguada Stream. April 24, 1945. R. T. Abbott collector. 127. 

 Flow sluggish. 4 feet wide. 2 inches deep : shady. 



