214 RESEARCH IN CHINA. 



Thorax with twelve rather narrow, slightly convex segments with pleural lobes 

 that arch slightly backward; axial lobe of each segment moderately convex and 

 unmarked, as far as known, by any tubercles or spines; at a clearly denned dorsal 

 furrow it unites with the pleural lobe, which is about one-third wider than the axial 

 lobe ; the pleural furrows originate at the anterior inner side of the pleural segment 

 and extend outward subparallel to the anterior margin about one-half the length of 

 the pleural portion of the segment; the deepest portion of the furrow is just within 

 the narrow anterior border, which is about one-fourth the width of the segment ; the 

 exterior half of the segment is gently convex and terminates in the rather bluntly 

 rounded end which may possibly be continued backward as a very short spine or 

 point. 



Pygidium large, moderately convex, with a short, convex axial lobe and very 

 broad, campanulate margin; axial lobe about one-half the length of the pygiclium, 

 marked by two shallow, transverse furrows that are continued out on the gentle 

 downward slope of the pleural lobes, outlining two segments marked by short, 

 shallow, narrow furrows ; the outer portions of the pleural lobe are nearly flat or 

 rising slightly toward the postero-lateral margins; the semicircular outline of the 

 pygidium is interrupted toward the median axis by a slight inward curvature. 



Surface slightly roughened, but not pitted or punctate, as far as can be deter- 

 mined. The outer half of the pleura is marked by imbricating lines subparallel to 

 the margins of the pleura. Similar lines also occur on the flattened border subpar- 

 allel to the margin of the pygidium 



The dimensions are as shown by figure 6 of plate 2 1 . 



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 Anomocare 

 [plate 18] and Anomocarella [plates 19, 20]. 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 segments of Coosia are unlike 

 those of both of the two genera mentioned in having short, slightly marked pleural 

 furrows. The pygidium of Anomocarella [plate 19, fig. 16; plate 20, fig. 6b] is quite 

 unlike that of Coosia; but the pygidium of Anomocare [plate 18, fig. ib] has the 

 broad, flattened margin seen in Coosia superba [plate 21, fig. 6]. 



Of the Chinese species referred to Coosia, C. carme (Walcott)* [plate 21, fig. 7] 

 appears to be the most nearly related. Coosis decelus (Walcott)* [plate 21, fig. 8] 

 has a somewhat similar frontal limb and border. Unfortunately the palpebral lobes 

 and posterior portions of the cranidium are unknown. Coosia ( 1) bianos (Walcott)* 

 [plate 21, fig. ioa] has a somewhat similar frontal limb, but with the fragments 

 available for comparison it is impossible to make identifications 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)* 

 [plate 21, fig. n] 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. robusta [plate 21, figs. 9, 90] is illustrated for 

 comparison, as it has a well-preserved cranidium and the pygidium is proportion- 

 ately more elongate than that of C. sitf'crha. 



Another form that is very close to this species is Coosia (?) limbata (Angelin) 

 illustrated on plate 2 1 , by figures 1 2 and 1 20, from the type locality at Andrarum, 

 .Sweden. Coosia (f) limbata differs materially, however, in having the very large 



'ki'furreil in IQJ5 to the genus Anomocarella. 



