REPORT ON UPPER PALEOZOIC FOSSILS FROM CHINA. 307 



In the interior this valve is furnished with two relatively large dental plates 

 situated well toward the sides of the beak. 



The shape of the dorsal valve is transversely subcircular. The convexity is 

 very low, the beak small, projecting but little beyond the hinge-line. Down the 

 center extends a median sinus, narrow and strong near the beak but widening rapidly 

 and losing in relative depth toward the front. No internal structures have been 

 ascertained for this valve, anything in the nature of plates apparently being absent. 



The shell substance is distinctly fibrous, and seems in most cases to be impunc- 

 tate. The appearance of very fine punctation, which I think I have noted in a few 

 instances, may be illusory. 



The real generic relations of this little shell are very obscure. More than any- 

 thing else it suggests an orthoid of the Dalmanella group, with which it agrees both 

 in configuration and in such points of structure, save in the very important one of 

 punctation, as it has been possible to determine. A certain amount of superficial 

 resemblance is manifested with some of the atrypoid brachiopods, especially such 

 as possess numerous fine ribs, as, for instance, certain species of Ccclospira; but it 

 is doubtful if the resemblance goes further than similarity of form. The presence 

 of dental plates seems to distinguish it from these spire-bearing shells. 



This species presents a superficial resemblance to a little shell from Tshau- 

 tien which Kayser figures as Rhynchonella sp., 1 and also to another form from the 

 same area which he describes as Airy pa ? tschautiencnsis;~ but these species are 

 represented as having a low fold and sinus in the dorsal and ventral valves, respec- 

 tively, while if anything the reverse is the case with the form under consideration. 

 Both the species mentioned are of Silurian age. 



Locality and Horizon. Pre-Pennsylvanian (?); near Ta-miau-ssi', East Ssi- 

 ch'uan (stations 6, 8, and 9). 



Schuchertella ? sp. 

 Plate 29, Figure 9. 



This species is represented by a single specimen, of so small size that one must 

 infer either that the species is very diminutive or that the specimen is immature. 

 The width is about 3 mm. and the length about 2 mm. The shape is semicircular, 

 but the outline may perhaps contract somewhat at the hinge. The convexity is 

 low, the surface being nearly flat, and the beak but very slightly prominent. The 

 configuration indicates that it is a dorsal valve with a low cardinal area. 



It is impossible to make an exact count of the ribs, which are moderately coarse 

 and angular. They are strongly and somewhat regularly unequal in size, three 

 or four more or less distinct gradations being present. Relatively coarse, strong 

 concentric lirae or crenulations characterize the spaces between the ribs without 

 surmounting them. 



The generic position of this little shell can not be certainly determined from 

 the characters shown, but these are in every particular such as are possessed by the 

 group Schuchertella, although Orihotetes, Streptorhynchus, etc., show the same general 

 features. To attempt a specific identification without a more complete representa- 

 tion of individuals seemed unprofitable, but the unusually coarse concentric crenula- 

 tions which the shell possesses promise an effective means of specific discrimination. 



Locality and Horizon. Pre-Pennsylvanian (?); near Ta-miau-ssi', East Ssi'- 

 ch'uan (station 9). 



'Richthofen's China, vol. 4, 1883, plate 4, figs. 3~3C. 

 'Idem, plate 4, figs. 12, i2a-d. 



