518 F. W. GAMBLE. 



vesicles not separate. Their contents, however, issue 

 by distinct ducts . . Sub-family HyporhyncMnae. 

 a. Characters of the sub-family 



Genus Hyporhynchus. 

 Species: — H. armatus (copulatory organ composed 

 of two fused chitinous, spiral tubes ; pigment 

 not reticular ; six papillae round the mouth. 

 H. penicillatus (copulatory organ composed of two 

 spoon-shaped pieces). 



6. A single genital aperture. Pharynx large, dolioform. 

 A uterus and paired testes present . Family VorticidsB. 



I. Germaria small, body-cavity capacious, free-living 



Sub-family Euvorticinae. 

 a. Two germaria and two unbranched vitellaria 



Genus Provortex. 

 Species : — P. balticus (copulatory organ with a 

 spirally-curved spur on the margin). P. affinis 

 (copulatory organ slightly bent distally). P. 

 rubrobaciUus (with red rods in the gut-cells; 

 copulatory organ with a finely pointed straight 

 spur to the margin) . 



Section C. — All(eoc(ela. 



Gut and parenchyma, with one exception (Plagiostomabi- 

 maculatum), distinct. Body-cavityabsentin the adult. Testes 

 follicular. Penis formed by a fold of the wall of the genital 

 atrium. A conspicuous chitinous copulatory organ absent. 



7. An otolith absent . . Family Plagiostomidae. 

 I. Genital aperture single, ventral, posterior. Mouth 



anterior. Germaria present. Sub-family Plagiostominae. 

 a. Without tentacles . . Genus Plagiostoma. 



Species : — a. With four distinct eyes : PL sagitta. 

 B. With two eyes. 



AA. Mouth terminal or subterminal : PL dioi- 

 cum (1 — 5 mm. long, yellow, pharynx in front of 



