64 



65 



Lake Pepin rmtcket, LamPsWs luteola (Lamarck), at various stages from young to adult. 



Figs. 62 and 63.— An adult gravid female, age about three years. Natural size. The right shell (fig. 65) has been 

 removed to expose the viscera. At m is shown the marsupium in which the young arc carried from theeggtotheglochidial 

 stage. Mussels grown under control in the experiments here described equaled this one in size at the age of first breeding, 

 two years and three months. 



Fig. 64. — Glochidia or parasitic stage in the young as they appear on leaving the parent mussel. One with valves 

 open may be seen at the middle left margin of the field. Photomicrograph. X27. 



Fig. 65.— Gill fdaments of a black bass infected with the glochidia of Lam psilis luteola 14 days after infection. Photo- 

 micrograph. 



Fig. 66.— Lell to right: Young mussels oi one, two , three, four, five and one-half months of age, respectively. Natural 

 size. 



