NODULARIA 951 
ordinary Nodularias, and Diplodon with almost or quite strict- 
ly radial sculpture. 
I have only been able to examine the soft parts of two spe- 
cies, which I have placed in this genus, the Unio japanensis 
of Lea and U. equatoria Morelet. In these there seemed to be 
no striking differences in the more obvious characters from 
the majority of the Uniones, but the embryos filled the inner 
gills above as in Diplodon, showing their near relationship with 
that great group. 
Section JANCEOLARIA Conrad, 1853. 
Lanceolaria Conrap, Pr. Acad. Nat. Sci. Phila., 1853, p. 268. 
Shell ensiform, solid, with a distinct, pinched-up posterior 
ridge, rounded in front, the posterior end sharp and generally 
turned a little to the right or left; beaks low, their sculpture 
nodulous, zigzag, often extending more or less over the sur- 
face; pseudocardinals rather stumpy, ragged, striate above, 
smooth below: anterior muscle scars distinct, the upper round, 
very deep, appearing as if bored out; pallial line truncate be- 
hind. 
Animal unknown. : 
Type, Unio grayanus Tea. 
NopULARIA GRAYANA (Lea). 
Shell exceedingly elongated, subinflated or inflated, inequi- 
lateral, rather solid; posterior ridge pinched up, cord-like, 
ending behind on the median line in a long, sharp point, some- 
times turned down a little; umbonal region compressed ; lun- 
ule long and well developed; anterior end rounded; base line- 
nearly straight, full near the posterior end; surface more or 
less sculptured, there being a series of subradial, slightly cor- 
rugated ridges at the middle of the disk, and a number of 
strong, subconcentric folds near the anterior end. ‘There is 
often some zigzag-radial sculpture in the umbonal region; epi- 
dermis olive, often with yellowish or green clouds, somewhat 
silky when fresh; ieft valve with two strong, rough, subcom- 
pressed pseudocardinals and two long, straight laterals; right 
