Synopsis Frksh-Water Mollusca 



75 



rayed ; beaks anterior ; pseudo-cardinals solid, stumpy or slightly elongate 

 in age, and shoAving a tendency toward being parallel with the laterals ; 

 nacre silvery, iridescent posteriorly. Marsupium kidney-shaped, not reach- 

 ing to the posterior end of the outer gill, though extending quite well for- 

 ward. 



Type: Uriio ellipsis Lea, fig. 205. 



Genus ACTINONAIAS Fischer and Crosse, 1893. 



Fig. 206 



"Shell ovate or subelliptical, distinctly longer than high, compressed or 

 slightly inflated, without, or with, indistinct posterior ridge. Disk not 

 sculptured. Beaks moderately ante- ^53^ 



rior, never in the middle of the shell 

 and never very near the anterior end. 

 Beak-sculpture poorly developed, con- 

 sisting of a few faint bars, which 

 have a tendency to become double- 

 looped, with the central part between 

 the loops obliterated. Epidermis yel- 

 lowish to greenish, generally with dis- Fig. 207 

 tinct rays. Male and female shells 

 differing in shape, but the difiference often hardly noticeable. 



Soft parts agreeing with those of Obovaria in every respect : the glo- 

 chidia also of the same type." (Ortmann.) 



Type: Unio sapotalensis Lea, (animal), fig. 207. 

 Example: A. ligamcntintis (Lam.), fig. 206. 



mp 



