Dendpoaoelopsis piriformis Kenk, 1953 



80 r^ 81 :^ 



bd ode gp 



Fig. 81 after Kenk (1953), 



A rather broad and plump species, up to 15 mm long and 3 mm wide. Head 

 truncated, with a bulging central portion of the frontal margin indi- 

 cating the site of the adhesive organ. In quiet gliding the greatest 

 width of the body is reached at the beginning of the last third. A pair 

 of rounded auricles protrude only little laterally, with a shallow con- 

 striction behind them. When resting, the body appears pear-shaped, the 

 lateral margins often showing a ruffled outline. Eyes usually two, 

 situated at a distance of about 1/3 the width, of the head. Pigmentation 

 dorsally brown or gray, with a dark field between the eyes and extending 

 to the frontal margin on both sides of the adhesive organ which itself 

 is unpigmented. There may be one median and often a pair of additional 

 lateral longitudinal dark stripes along the body. Ventral side lighter 

 gray. Pharynx short, of the dendrocoelid type. Testes numerous, dorsal, 

 arranged in a pair of wide bands reaching close to the posterior end (in 

 the similar D. vaginata the testes are ventral). Penis with large, 

 spherical bulb and long, finger-shaped, pointed papilla. Sperm ducts 

 enter the bulb anterolaterally and open into the seminal vesicle inde- 

 pendently, each on a conical projection. Seminal vesicle large, with 

 glandular wall of irregularly lobed outline. Ejaculatory duct narrow and 

 long, opening at tip of penis papilla. Common oviduct opens into atrium 

 close to gonopore. Bursa and bursal canal without peculiarities. In- 

 habitant of lakes and streams in Alaska and northwestern Canada. Principal 

 literature: Kenk (1953), Holmquist (1967). 



N 



59 



