242 ANNALS OF THE CARNEGIE MUSEUM. 
ciduous, often absent, sometimes torn. Branchial opening with 
papilla on inner edge, anal with distinct, but small papillae. Palpi 
subfalciform, pointed behind, their posterior margins connected for 
about one-third to one-half of their length. 
Fic. 4.  Fusconaja rubiginosa (Lea). Male, from South Fork of Tenmile Creek, 
Waynesburg, Greene Co., Pa. (Carn. Mus., No. 61, 4,509.) _ Coll. May 6, 1910. 
Gills short and rather wide, with curved lower margins (correspond- 
ing to the shape of the shell), the inner gill wider. Outer gill attached 
at its anterior end at the highest point of the attachment-line of the 
mantle, far above the palpi; in- 
ner gill with its anterior end 
slightly in front and below that 
of the outer gill, widely separated 
from the palpi. Outer lamina 
of outer gills entirely connected 
with the mantle. Inner lamina 
of the inner gill free from the 
abdominal sac, except at its an- 
terior end. Behind the foot, the 
Fic. 4a. Left gills of a sterile female from : ; : 
two inner lamine of the inner 
same locality. 
gills are connected up to their 
posterior end. Thus a complete gill-diaphragm is formed, which 
reaches backward close to the posterior margin of the mantle. 
Both gills possess well developed septa and water-tubes, running 
parallel to the gill-filaments. Inthe male, the septa are rather distant 
and the water-tubes are wide. The septa are merely lines of con- 
nection of the interlaminar tissue. In the female, all four gills are 
marsupial, the septa are better developed, thicker and longer (in the 
