283 



Although the reproductive phase of L. ventricosa of the Lake is 

 much less conspicuous than in the river mussels, most of them appar- 

 ently succeed in reproducing themselves. Most of the females found 

 later in autumn have more or less numerous glochidia in the gills. No 

 infected fishes or very young mussels of this species were seen. 



The most common parasite is Atax, and it is not particularly 

 abundant. Of 6 examples collected near Farrar's .July 24, 1909, the first 

 contained 9 of the mites, the second 4, the third 15, with Atax egg.? in 

 mantle and body, the fourth 12 Atax and numerous eggs of the mite on 

 the inner surface of the mantle, the fifth 3 Atax with eggs, and the 

 sixth 7 Atax with eggs and egg scars. No other parasites were noted. 

 No pearls were found, only a few irregular slugs. 



In 1906 some of the immense L. ventricosa of Yellow River were 

 planted in the lake near shore not far from the old ice office. A few 

 died shortly after planting but near the same place two years late- 

 some of the mussels were found alive and apparently thriving. Two of 

 the large females were killed and examined. Although this was at a 

 time when this species is usually gravid, one of these individuals was 

 sterile, apparently having failed to become impregnated. The influence 

 of its residence in the lake was marked by a dark stain which covered 

 the exposed portion of the shell. The other had a few eggs in the gills, 

 and numerous marginal cysts in the mantle. About 10 Atax among the 

 gills, and numerous distomids on the outside surface of the mantli in 

 the umbonal cavity. 



