516 F. W. GAMBLE. 



organs present. Pharynx usually mid-ventral, rosulate (i. e. 

 rosette-like) .... Family Mesostomidse. 



I. A single genital aperture, two germaria, and two 

 vitellaria. Accessory reproductive organs absent 



Sub-family PromesostominaB. 

 a. Characters of sub-family . Genus Promesostoma. 

 Species : — P. marmoratum (copulatory organ coiled, 

 crosier-like). P. ovoideum (penis pyriform, pig- 

 ment-cup of eye simple). P. solea (pigment-cup 

 of eye with hook-like process over outer surface of 

 lens). P. lenticulatum (copulatory organ provided 

 distally with radial triangular ridges). P. agile 

 (copulatory organ curved, simple). 



II. Two genital apertures. The male pore in front of the 

 female. Germarium single. Sub-family Byrsophlebinse. 

 a. Characters of sub-family . Genus Byrsophlebs. 



Species: — B. Graffi (vitellaria unbranched; copula- 

 tory organ widely funnel-shaped, the terminal margin 

 with a triangular projection). B. intermedia (vitel- 

 laria branched, copulatory organ elongate, the 

 terminal margin entire, and with a curved chitinous 

 spur). 



III. A common genital aperture. Germ-yolk-glands 

 present. Testes rounded. Sperraotheca with chitinous 

 appendages . . . Sub-family Proxenetinae. 

 a. Characters of sub-family . Genus Proxenetes. 



Species: — P. flabellifer (copulatory organ retort- 

 shaped, complex; duct of the spermotheca with 

 chitinous teeth). P. cochlear (copulatory organ 

 composed of three spoon-shaped pieces). 



IV. A common genital pore. One germarium. Female 

 accessory organs present. Testes elongate 



Sub-family Eumesostominae. 



a. Copulatory organ traversed throughout its length by 



the ducts of male secretions . Gehus Mesostoma. 



