AbstractsBiology & Animal Science

In connection with the extensive investigation of the Unionidae which has been conducted by the Bureau of Fisheries for the past four years, with a view to determining the feasibility of artificial propagation of the mussel on a commercial basis, it was thought worthwhile by the writer to make a careful study of the marsupium of a large number of genera, including as many as possible of the distinctive types, as classified by Simpson in his "Synopsis of the Naiadesu". The method of this investigation has been to study material taken at various intervals, beginning with the marsupium in a pre-gravid condition, arid progressing through the various stages of gravidity to the post-gravid condition. In this manner, it has been found possible to determine just what histological changes occur in the epithelial lining of the water tubes, which, as has long been well known, function as marsupial pouches for the embryos until the latter are discharged as glochidia. The report as herewith presented is the result of investigations conducted for the Bureau of Fisheries during three summers at the Biological Station, Fairport, Iowa and also at the Marine Biological Laboratory, Woods Hole, Mass.