318 RESEARCH IN CHINA. 
Chonetes aff. C. flemingi Norwood and Pratten. 
Plate 29, Figure ro. 
The subject of this description is a single specimen which has a width of 7 mm. 
andalengthof6mm. ‘The shape is semicircular, the convexity high, the beak large 
and projecting, the umbo inflated, and the ears rather large and depressed. The 
sinus is narrow and obscure. The number of spines is not known. About 11 ribs 
occur in the space of 2mm. As the shell is exfoliated the surface details can not be 
determined. A very small area which is fairly well preserved, however, seems to 
show that the ribs were narrow and sharp, with relatively wide, rounded interspaces. 
This specimen is unusually long for its width, and probably does not show the 
average dimensions of the species. It much resembles Tschernyschew’s figures of 
C. flemingi Norwood and Pratten, especially figure 10 of plate Lvi.! Typical C. 
flemingt differs in having a more distinct sinus and probably in the character of the 
surface ornamentation, although only an imperfect comparison is possible. 
With the specimens from which the above description was taken occurs another 
very young example, which possibly may not represent the same species. 
Locality and Horizon.—Pennsylvanian; Y6n-yi-ssi, Shan-si (station 20). 
Chonetes sp. 
Plate 29, Figure 11. 
Of this species our collection contains four specimens, two from station 69 and 
two from station 17. Only one specimen from each lot is sufficiently perfect to 
serve in drawing up a description. The following characters are found in the example 
from station 17, a ventral valve. 
The width is 6 mm. and the length 3.5 mm. ‘The shape is subsemicircular, 
flattened in front. The convexity is rather low and the umbonal region slightly 
inflated. ‘The sinus is broad and faint, or possibly absent altogether. "The number 
of cardinal spines is unknown. ‘The ribs come about seven in 2mm. While quite 
distinct, they are nevertheless unusually broad and low. ‘There are in addition 
fine concentric strie, which are also faint. 
The specimen from station 69, likewise a ventral valve, resembles in a general 
way that just described. The size and configuration are about the same, except 
that the width is proportionately less. The striation is equally fine, but the ribs 
appear to be somewhat more strongly elevated. Although it is possible that the 
two forms do not belong to the same species, the characters shown are not sufficient 
to warrant their separation. On the other hand, it is possible that the form allied 
to C. flemingi may be specifically the same as the present, the difference of shape, 
convexity, and surface being the result of individual variation or the effects of 
preservation, such as, for example, compression. This does not seem to me suffi- 
ciently probable, however, to warrant adopting this interpretation. 
Under this title also has provisionally been placed a specimen from the cherty 
beds of Shan-tung (station 59). It shows the mold of the interior of a dorsal valve. 
The width is only about 3.5 mm. and the length about 2 mm. The cardinal line 
is equal to the greatest width below, the shape being subsemicircular, somewhat 
flattened at the sides and front. There are about 20 rows of internal spines, indi- 
cating a corresponding number of ribs, the distance between the rows being about 
as in specimens from station 69. Areas near the cardinal line upon both sides, 
including in all about one-third the entire surface, are smooth. 

1Mém. Comité Géologique [Russia], vol. 16, No. 2, 1902. 
