Dendroaoelopsis vaginata Hyman, 1935 



m b vd vs 



bd de f am ac gp ode 



Mature specimens 14-22 mm long and about 3 mm wide. Head truncate, with 

 gently bulging frontal margin, a weak subterminal adhesive organ, rounded 

 corners, and a slight narrowing (neck) behind them. Eyes usually two, 

 their distance from each other about 1/3 the width of the neck, the dis- 

 tance of each from the frontal margin a little larger than from the later- 

 al margin. Dorsal side gray or brown, ventral surface somewhat lighter 

 (the pigment bleaches easily after preservation) . Pigment absent from 

 the two eye fields, a point near the mouth, and a circular area around the 

 gonopore. A pair of somewhat lighter oblique streaks on the head laterally 

 to the eyes. Similar to D. piriformis but with different body outline 

 (largest width is reached in the prepharyngeal region). Testes numerous, 

 ventral, reaching to level of gonopore (in D. piriformis dorsal, to pos- 

 terior end). Penis with large spherical bulb and finger-shaped papilla. 

 The bulb contains a large, round, highly glandular seminal vesicle and 

 receives the two sperm ducts ventrolaterally. From the vesicle a narrower 

 ejaculatory duct proceeds to the tip of the papilla. Below the flattened 

 outer epithelium of the penis papilla is a dense fibrous layer followed 

 by a layer of longitudinal muscles. The outlet of the copulatory bursa 

 widens as it proceeds posteriorly and gradually acquires a folded outline. 

 It opens into the atrium close to the gonopore. Egg capsule spherical, 

 about 1.6 mm in diameter. Springs, streams, and lakes in Montana, Oregon, 

 and Washington. Literature: Hyman (1935). 



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