REPORT ON UPPER PALEOZOIC FOSSILS FROM CHINA. 325 
four of these are developed as plications of the shell, the remainder appearing on 
the margin as denticulations. Even these four, however, are obscure, and decrease 
in intensity in proportion to their distance from the sinus. 
The dorsal valve is subcircular in outline, highly gibbous. The beak is small, 
pointed, slightly prominent. ‘There is a strong, deep, ill-defined mesial sinus, which 
projects in front as a sort of linguiform extension corresponding to a deep emargi- 
nation of the front of the opposite valve. The sinus, which dies out long before 
reaching the hinge-line, is subdivided by a strong mesial fold, extending about as 
far from the edge as the sinus itself, and each of the two channels thus formed is 
apparently again subdivided by an obscure plication limited to the marginal region. 
On each side of the sinus there are about six plications, shown rather by denticula- 
tions at the edge of the shell than by folds upon its surface. 
Internal structure unknown. Shell strongly and finely punctate. 
As only a single specimen of this form was found it was impracticable to muti- 
late it for the purpose of ascertaining its internal structures; therefore the generic 
position of the species is somewhat conjectural. The shell structure and configura- 
tion consign it at once to the Terebratulid, and in the character last mentioned 
it much more closely resembles the genera Notothyris and Hemiptychina than the 
plicated Dielasmata. Itissomewhat uncertain whether this fossil should be regarded 
as having a dorsal sinus in which a mesial rib has been developed, or a dorsal fold 
with two deep channels upon its sides; but the former interpretation seems to be 
more natural. Upon that view the species under consideration would be one of 
the antiplicati, and its generic position would be with Notothyris in preference to 
Hemiptychina. On one side of the specimen may be noticed an appearance similar 
to that often observed in Dielasma when fracture or cleavage takes place along the 
dental plates, but in the present case this may be due to exfoliation of the thick 
shell. Of course the presence of dental plates would debar this form from Notothyris 
and Hemiptychina alike. 
In its specific relations this form differs sufficiently from any of the species 
whose descriptions have come into my hands to make a detailed comparison unneces- 
sary. Itis perhaps as near as any to N. inflata Waagen and N. djoulfensis Abich. 
Locality and Horizon.—Pennsylvanian (Wu-shan limestone) ; near Liang-ho-k’6éu, 
East Ssi-ch’uan (station 7). 
Schizodus cf. S. curtus Meek and Worthen. 
Plate 29, Figure 27. 
This species is represented by three or four specimens preserved as molds of the 
interior. ‘The shape and dentition are those of Schizodus, and the specific characters 
indicate an affinity with a little shell figured by de Verneuil as S. rossicus var. and 
also with our American species S. curtus. The width is 9 mm. and the height some- 
what less, about 8mm. ‘The general shape appears to have been subcircular, but 
with the posterior portion of the basal outline straightened and with a long posterior 
truncation directed toward it at something less thana right angle. The beak is not 
very prominent, but makes a distinct projection in the outline. In some cases the 
umbonal ridge seems to have been ‘well marked, in others more obscurely marked. 
One would hardly venture to identify this form directly with S. rossicus, but it 
is very similar to a specimen figured by de Verneuil under the title of S. rossicus var.} 
It differs, however, in having a less transverse shape, a sharper inferior-posterior 
angle, and a less strongly inclined truncation. ‘Though closely similar to S. curtus, 
it seems to differ from some of Meek’s figures in having a less prominent and pro- 

1Murchison, de Verneuil, and Keyserling, Geology of Russia and the Ural Mountains, vol. 2, 1845, 
pt. 3, plate 19, fig. 8. 
