REPORT ON UPPER PALEOZOIC FOSSILS FROM CHINA. 321 



The surface lacks ribs either upon the sides or on the fold and sinus, but is 

 marked by very fine radiating striae. 



I know of no Carboniferous species which really requires comparison with the 

 present. In general appearance it suggests a Rcticularia, such as R. lincaia, but 

 the fine continuous lira can hardly be interpreted as marks left by the spines which 

 characterize that group. 



The development of fine subsidiary line seems to be a much more common 

 feature in the English Reticularise (wide R. lincata var. rcticulata), judging from 

 Davidson's description and figures, than in the American, where it is essentially 

 unknown. We have at least one, though a little known, form po ssessing this character 

 which was apparently described by Swallow as Spirigera pronti. I am not prepared 

 to speak positively as to the internal structure of this type, but dental plates and 

 septa seem to be absent or but slightly developed. In the American Reticularias 

 (R. pseitdolineata, etc.), and I suppose in the European ones, there is a median septum 

 in both valves, while the ventral valve possesses long dental plates as well. The 

 Chinese shell thus differs in structure from the lineatus group of Spiriferi, although 

 it shows some points of superficial resemblance. 



Spirifcr blackwelderi differs from S. lineatus as identified by Kayser from 

 Chinese specimens, as well as from any other Chinese species identified or described 

 by him, nor can it be found among the shells described by Waagen from India or 

 by Tschernyschew from Russia. In fact, closer parallels can be drawn with certain 

 Silurian forms, such as Spirifer radiatus, than with those usually found in the Car- 

 boniferous. In the radiatus group, as in 5. blackwelderi, the ventral valve possesses 

 dental plates, but while socket plates, and sometimes a low septum, are found in 

 the dorsal valve of the former, that of 5. blackwelderi appears to be without those 

 structures. 



Locality and Horizon. Pennsylvanian (Wu-shan limestone) ; near Ta-ning-hien, 

 East Ssi-ch'uan (stations i and 2). 



Spirifer sp. (a). 



This species also is known only in a fragmentary manner. The width of the 

 largest specimen, which is a ventral valve, is 98 mm. and the length 55 mm., the 

 latter diameter being by far the least complete. The actual width was probably 

 not much over 100 mm. The actual length is very largely a matter for conjecture; 

 probably it was about 75 mm. The area is broad, seemingly almost the full length 

 of the shell, but it appears to be rather narrow. As nearly as can be ascertained 

 it is 15 mm. high at the beak. The sinus is distinct, but shallow and ill defined. 



The side presented to the observer is the interior. Part of the exterior has been 

 uncovered, but no ribs or other ornamentation can be discerned. This feature, 

 therefore, seems to be as in Martinia, or possibly Squainularia; but the broad cardi- 

 nal line, the shape (which is probably very transverse), and the curvature (which in 

 spite of manifest crushing appears to be low) put a negative to any such association. 

 We must have in this specimen either a Spirijer of a novel type or, more probably, 

 one which by attrition or imperfect preservation has lost its proper surface char- 

 acters. At the same time, if ribs at all well developed were originally present, the 

 loss must have been considerable to have obliterated them altogether, and it would 

 seem to be impossible that had they been grouped in fascicles, as in the camcratus 

 type of Spirifer, this structure could have been destroyed, fascicles and all. 



On the hypothesis that this form originally possessed well-marked ribs it might 

 be compared with several forms found in the Salt Range of India, but hardly with 

 anything yet known from China. The loss of the ribs would be easier to under- 



