288 ANNALS OF THE CARNEGIE MUSEUM. 
tube; the latter forms the ovisac, containing the eggs and embryos, 
and this ovisac is also closed at the base of the marsupium by a 
fine membrane.”® 
The eggs and glochidia fill the ovisacs without forming placente, 
and the glochidia are discharged through the anal opening in rather 
irregular masses. Glochidia’? rather large, triangular, with hooks. 
They are about as long as high, 0.35 mm. (see Plate XIX, fig. 2). 
Having seen only alcoholic material I refrain from describing the 
colors of the soft parts. 
Anodonta complanata Rossmessler. 
See also Ortmann, I9IIc, p. 22. 
Six specimens from Dinkelsbueh], Bavaria, and ten specimens from 
Buda-Pest, Hungary, are at hand, received from W. Israél. Among 
them are gravid females. 
Fic. 14. Anodonta complanata Rossmessler. Male, from Weernitz River, 
Dinkelsbiihl, Bavaria. (Carn. Mus., No. 61, 4,958.) 
Inner edge of anal opening with very fine papilla. Gills (see Plate 
XVIII, fig. 9) essentially of the same structure as Anodonta cygnea, 
26 That the lateral water-tubes are actually parts cut off from the original water- 
tube by folds is conclusively shown by fig. 8,-Plate XVIII. This is a slide made 
from a female, in which the eggs were just beginning to go into the marsupium. 
Attention should be called to the fact that in this species I never found the lateral 
water-tubes complete. This may be due to the fact that all my material was col- 
lected early in the breeding season. Nevertheless, some of the specimens had fully 
developed glochidia. 
27 The glochidia have been figured by Fleming (1875, pl. 4, fig. 4) and Schierholz 
(1880, pl. 2. fig. 26), their measurements, 0.35 mm., have been given by Harms 
(1909, p. 332) and Haas (19104, p. 110). 
