96 . SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



imbricating- lines subparallel to the margins of the pleura. Similar 

 lines also occur on the flattened border subparallel to the margin of 

 the pygidium. 



Dimensions. — The dimensions are as shown by figure i of plate i6. 



Obscnmtions. — This fine species represents a small group of 

 species that occur in the Cambrian rocks of northern Alabama in 

 the United States and in the Middle Cambrian rocks of the province 

 of Shan-tung, China. The cephalon is not unlike that of Anoniocare 

 and Anomocarella. It differs from the former in having small 

 palpebral lobes and a broad, slightly convex frontal border, and from 

 the latter in the character of its frontal border. The thoracic seg- 

 ments of Coosia are unlike those of both of the two genera men- 

 tioned in having' short, slightly marked, pleural furrows. The 

 pygidium of Anomocarella is quite unlike that of Coosia; but the 

 pygidium of Anomocare has the broad, flattened margin seen in 

 Coosia superba. 



Of the Chinese species referred to Coosia, C. carmc (Walcott)' 

 appears to be the most nearly related. Coosia decelus (Walcott)' has 

 a somewhat similar frontal limb and border. Unfortunately the pal- 

 pebral lobes and posterior portions of the cranidium are unknown. 

 Coosia bianos (Walcott)' has a somewhat similar frontal limb, but 

 with the fragments available for comparison it is impossible to make 

 indentifications of value ; the same is true of the associated pygidium, 

 of which only the central portion is known ; this indicates, however, a 

 comparatively broad margin. Coosia daunus (Walcott),^ although 

 having a similar frontal limb and form of glabella, undoubtedly 

 belongs to a different genus or subgenus ; this is indicated by its very 

 strongly pitted surface. 



A second species from Alabama, C. robiista (pi. i6, figs 2, 2a), 

 is illustrated for comparison as it has a well preserved cranidium 

 and the pygidium is proportionately more elongate than that of C. 

 superba. 



Another form that is very close to this species is Anoniocare 

 limbatum Angelin. It differs materially, however, in having the very 

 large eye-lobe characteristic of Anomocare Iceve (pi. 17, fig. i), the 

 type of the genus Anomocare. I think that in all probability with the 

 securing of entire specimens of A. limbatum the species will be found 

 to have characters intermediate between Coosia and Anomocare. For 

 the present, however, I will refer it to the genus Coosia, subgenus 

 undetermined. 



' Referred in 1905 to the germs Anomocarella. 



