﻿SNAIL HOST OF ORIENTAL LUNG FLUKE — ABBOTT 79 



A comparative study of size and position of papillae was made in 

 7' Mara {Plotiopsis) scabra Miiller, Sermyla riquetii Grateloup, and 

 certain species of Stenomelania. While these mantle characters may 

 be useful in generic determinations, it is felt that they are insufficiently 

 distinct to separate species within the genus Thiara. Until now it was 

 thought that the papillae-bearing Thiaridae were limited to the Old 

 World, but examination of living specimens of Ilemisinus cubanianus 

 (Orbigny) from Cuba shows that this New World mollusk possesses 

 mantle papillae very similar to those of Thiara granifera. The 7 

 papillae to the left are bulbous at their bases and extend beyond the 

 edge of the shell. To the right of these are 13 to 14 small papillae. A 

 solitary, long papilla to the far right is absent. Like Thiara^ 

 Hemisinus possesses a brood pouch on the back and a large birth pore 

 on the right side. 



Behind the row of papillae on the mantle of T. granifera there is a 

 sharply impressed groove that runs parallel to and is superimposed 

 on the edge of the shell. Posterior to this is the rather prominent 

 circumpallial blood vessel. Welded to the inside of the mantle well 

 within the mantle cavity are, from left to right, the osphradium, the 

 ctenidium or gills, the urogenital ducts, and the rectum. A more de- 

 tailed description of these organs is given under their respective 

 systems, in the section on internal anatomy (p. 90) . 



Color of animal : Color of animal in general a dark yellowish gray. 

 Underside of foot an opaque grayish white with 10 to 20 widely scat- 

 tered, round, yellow dots. In some colonies the underside of the foot 

 has an additional pinkish undertone. Side of foot speckled with 

 clumps of tiny, black-gray spots, which anteriorly become thin, short, 

 black irregular lines of color. Proboscis gray with transverse black, 

 fine striations, which are more prominent dorsally but disappear on 

 the ventral surface. Toward the anterior end and on the dorsal side 

 is a prominent, inverted, V-shaped, black, transverse color band, which 

 is characteristic of the genus Thiara. Anterior edge of proboscis with 

 small, embedded, yellow color-granules. The labial pads are pinkish 

 gray. Tentacles translucent gray to colorless with irregularly spaced, 

 narrow, circular bands of blackish gray. One of these bands crosses 

 the small, black eye. Kelatively large, embedded, yellow color-spots 

 are often present in the tentacle. The mantle papillae are colored 

 similarly to the tentacles. Inside of mantle a brilliant copper-green. 

 Birth pore usually tinted with pink. 



INTERNAL ANATOMY 



A general orientation is presented here as an aid to parasitologists 

 who may wish to examine snails that have been experimentally infected 

 with larval trematodes. In most instances only the digestive gland 



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