﻿SNAIL HOST OF ORIENTAL LUNG FLUKE — ABBOTT 85 



The marginals are slightly spatulate and very similar in appear- 

 ance. The inner marginal is always slightly shorter and narrower 

 than the outer marginal. There is considerable variation in the num- 

 ber of denticles, with the counts of each often overlapping the other. 

 The inner marginal has been observed to bear 9, 8, or 7 denticles, the 

 outer marginal 12, 11, 10, or 9. The most important feature of the 

 outer marginal is a small, sharp, thumblike protrusion on its outer 

 edge. This feature has not been previously recorded in the literature, 

 and has also been found by the author in other members of the 

 Thiaridae. It is easily overlooked, and usually requires fresh material, 

 which is observable in water mounts. 



Esophagus : The thin-walled, rather narrow esophagus dips ven- 

 trally upon leaving the buccal mass and then passes through the brain, 

 with the central ganglia dorsal to it, the pedal ganglia below, and the 

 cerebro-pedal commissures on each side. It travels in a straight line 

 posteriorly along the underside of the large brood pouch and emerges, 

 with a slight twist to the right, over the end of the columellar muscle. 

 It then passes up past the lower stomach and joins the posterior or 

 upper stomach at its posterior and ventral end. 



Stomach : The stomach is a rather large sac located in about the 

 second-to-the-last whorl and is bounded posteriorly by the large di- 

 gestive gland and anteriorly by the heart and kidney. The stomach 

 has a circular constriction at its center, which divides the lower stom- 

 ach or crystalline sac from the upper stomach proper. 



The esophagus enters the stomach at one comer at the posterior 

 end. Below the esophageal entrance is a large, grooved, central mass, 

 or core. The remainder of the sides of the stomach are lined with 

 40 to 50 raised, transverse lamellae or platelets. At the bottom of the 

 stomach on the side opposite the central core is the small, circular 

 opening from the crystalline style sac. The food passes slowly down 

 the stomach, across this entrance and over to the corner, where it exits 

 into the intestine. 



The crystalline style sac is essentially a diverticulum of the stomach 

 proper. It often appears as a transparent sac in fresh material. 

 Within its thin walls is a round, folded hyaline sheath, iridescent, and 

 open at its posterior end, which faces the stomach. Within this is 

 the crystalline style itself, shaped like a dumbbell and jellylike in 

 consistency. 



Two rather large openings are present not far from the esophageal 

 opening at the posterior end of the stomach proper, which constitute 

 the connection with the hepatopancreas, or digestive gland. The top, 

 or spire whorls, of the animal contain the digestive gland, which an- 

 teriorly partially enwraps the upper stomach. 



Intestine: The intestine is thick walled, fairly large, and round. 

 It passes downward in close contact with the crystalline style sac, on 



