274 



Annals of the Carnegie Museum. 



Unio pictorum (Linnaeus) 175S. 

 See also Ortmann, 1911c, p. 21. 

 A large number of specimens, both males and females, are at hand, 

 from various parts of Germany and Hungary, received from W. 

 Israel. 



sa 



Fig. 11. Unio pictorum (Linnaeus). Male, from Saale River, Rudolstadt, 

 Germany. (Cam. Mus., No. 61, 4,934.) 



Branchial opening separated from the anal by a complete diaphragm 

 formed only by the gills. Anal opening closed above by the union 

 of the margins of the mantle, forming a supra-anal; this mantle-con- 

 nection is rather long, slightly longer than the anal, and about as long 



as the supra-anal. Inner edge of bran- 

 chial with distinct papillae, that of the 

 anal almost smooth, or with very minute 

 crenulations. In front of the branchial 

 the inner edge of the mantle is practically 

 smooth. Palpi subfalciform, their pos- 

 terior margins united for about one-third 

 of their length, or slightly more. 



Gills (corresponding to the shape of the 

 shell) rather long and narrow, the inner 

 the wider, chiefly so anteriorly. Anterior 

 end of the gills as usual, that of the inner 

 widely distant from the palpi. Outer 

 lamina of outer gill entirely connected 

 with the mantle, inner lamina of inner 

 gill free from abdominal sac, with excep- 

 tion of its anterior end. 

 Both gills with well-developed water-tubes and continuous septa. 

 The septa of the inner gill of the male (see Plate XVIII, fig. 3) and 



mp 



Fig. u a. Left gills of a sterlie 

 female, same locality. 



