32 THE SHORTER SCIENTIFIC PAPERS 



Testes in segment 5 or 7 (rarely in segments 8 and 9). 

 Ovaries in segments 6 and 7 (rarely in segment 10). 

 Spermatheca in segment 5 or 7. Reproduction normally 

 asexual by budding. Length of specimens varies from 1 

 to 50 mm.; usually from 2 to 10 mm. 



Usually in fresh water, rarely in saline waters. One 

 (Amphichasta) marine. Cosmopolitan; fifteen genera. 



Synoptic Table for Separation of Described Genera 



(Genera occurring in North America printed in capitals) 



A-*^. Capilliform setas absent. 



B^. Dorsal bundles of setse absent. 



C^. Ventral bundles of setse on all segments beginning with the 

 second. Third segment not longer than remaining segments 



Schmardella. 



C^. Ventral bundles of setas absent on segment 3-5. Segment 3 

 extremely long CHiETOGASTER. 



B^. 2 dorsal and 2 ventral bundles of setse on a segment. 



C^. Segment 3 much longer than remaining segments. Length 

 (of described species) not exceeding 2 mm. . . Amphichoeta. 



C^. Segment 3 not longer than remaining segments. Length (of 

 described species) equal to or exceeding 5 mm. 



D^. All setse of dorsal bundle biuncinate Paranais. 



D^. Some of the seta; of dorsal bundle not biuncinate .... 



OPHIDONAIS. 

 A^. Capilliform seta: present in the dorsal bundle. 



B^. Dorsal bundle of setse beginning on segment 2, 5, or 6. 



C^. Dorsal bundle of setse beginning on segment 5 or 6. 



D^. Posterior end developed into a tubular respiratory proc- 

 ess containing paired gills. Usually living in tubes 

 composed of plant fragments, etc DERO. 



D^. Posterior end without respiratory processes. 



E^. Capilliform setse of dorsal bundle with a series of prom- 

 inent teeth. Dorsal bundle beginning on segment 5 



Vejdovskyella.^ 



E^. Capilliform setse without teeth. Dorsal bundle begin- 

 ning on segment 6. 

 F^. Length of capilliform setse equal to at least twice 

 the diameter of the body. 



G^. Capilliform setse on all segments beginning with 

 6. Prostomium rounded Macrochoetina. 



■"^For Bohemilla, previously used as the generic name for a group of Trilobites by 

 Barrande, (Michaelsen, :03). 



