NO. 1415. CAMBRIAN FAUNAS OF CHINA— WALCOTT. 41 



the free cheek; it there cuts directly across the lobe, leaving a short 

 portion of the broad margin extending obliquely forward and outward 

 to the base of the postero-lateral spine; in front of the palpeln-al lobe the 

 facial suture extends forward and slightly outward to the front margin. 



There are several specimens of an hypostoma associated with the 

 species that appear to belong to it. The central portion is convex, 

 subovate, and crossed toward the front by a strong furrow subparallel 

 to the rounded front margin; a narrow rim surrounds the front and 

 expands into two ear-like flattened projections opposite the strong fur- 

 row crossing the central portion; the margin then contracts so as to 

 leave a narrow, rounded rim opposite the convex portion of the pos- 

 terior part of the central body; it then expands so as to form a 

 subtriangular limb on each side at the postero-lateral angles of the 

 hypostoma. This hypostoma is of the same type as that of DanieseUa 

 hlachwelden. 



The associated pygidium is transversely semicircular, with a spinose 

 margin and convex conical axis. The axis is divided into live rings 

 and a subtriangular terminal portion by five transverse furrows; the 

 two anterior rings are rather convex, while the three posterior are but 

 slightly defined by shallow, narrow, transverse furrows. The pleural 

 lobes are slightly convex out to the geniculation, where the slope is 

 somewhat abruptly downward to the end of the falcate termination of 

 the segment outlined on the lobe; the furrows crossing the axis extend 

 out on the pleural lobes, so as to define a narrow anterior segment and 

 four posterior segments and a central portion extending down from 

 the axis; each of the segments terminates in a falcate, backward-curv- 

 ing, short, flat spine, of which there are six on each side, one for each 

 of the segments and two back of the axis; there does not appear to be 

 any clear indication of a border, as the space is occupied entirely by 

 the segments and their falcate ends. 



The surface of the glabella, fixed cheeks, free cheeks, and occipital 

 ring is marked by numerous, rather closely set, depressed pustules, 

 between and on which there are very fine puncta?, as determined by a 

 strong lens. The surface of the pygidium is marked by strong pus- 

 tules or granules that are thickly set on the segments but not on the 

 furrows. There appears to be considerable dift'erence in the strength 

 and size of the granules on difl'erent specimens. This may be simply 

 a matter of the state of preservation, or the amount of w^ear to which 

 the crust has been subjected, or it ma}^ indicate a variety or even a 

 difl'erent species. 



A head ?> mm. in length has a width of .5 mm. at the exterior of the 

 palpebral lo))es, and a width at the base of the glabella of 2 mm. 



Obserratlo?is. — The p3"gidium illustrated by M. Bergeron and named 

 Dicellocephalns f sinensis,^'' which occurs at this same stratigraphic 



«Bull. Soc. Geol. de France, ?A ser., XXVII, 1899, p. 48. 



