34 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



Formation and locality. — Middle Cambrian, central portion of 

 Chang Hsia formation, in hard, gray, fine-grained limestone; 3.25 

 miles southwest of Yen Chuang, Hsin Tai, Shangtung, China. 



Collected l\y Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



Genus DAMESELLA, ne^A?• genus. 



Diagnosis. — General form elongate, ovate, distinctly trilobate, mod- 

 erately convex. Head transversely semicircular, with the postero- 

 lateral angles rounded or spiniferous; the anterior and lateral margins 

 have a thickened or elevated border, within which there is a well- 

 marked furrow. Glabella truncato-conical, marked with two or more 

 pairs of short furrows; occipital furrow strongly defined; occipital 

 ring rounded. Fixed cheeks rather broad. Free cheeks subtriangu- 

 lar in outline, rising with a gentle curvature to the base of the eye 

 lobe; the border is extended into a lateral spine a short distance in 

 advance of where it is cut by the facial suture. Facial suture, cutting 

 the anterior border nearly opposite the base of the inner margin of 

 the palpebral lobe, extends with slight curvature backward to the 

 palpebral lobe; curving about the latter it extends outward and back- 

 ward, cutting the posterior margin a little in front of the rounded 

 postero-lateral angle. Eyes small, elevated, and situated about mid- 

 way of the glabella. 



Hypostoma sub-rhomboidal in outline; central portion strongly 

 convex, elevated, with an irregular border at the back and sides, 

 broadening out in front to a greater width than at the back. 



Thorax with twelve or more transverse segments; axis about one- 

 third the width of the thorax, gradually narrowing posteriorly, 

 Pleurffi nearly horizontal, at right angles to the axis out to the point 

 where they cuvre gently backward before terminating in a falcate 

 extremity; pleural groove long, deep, and broad, starting at the dorsal 

 furrow near the front and extending out on the falcate end. 



Pj^gidium sub-semicircular; axis convex, broadlj^ conical, and divided 

 into four or more rings by transverse furrows; lateral lobes depressed, 

 convex, and divided by furrows into four or more segments; border 

 rounded, and bearing five or more spines on each side. 



Surface in the type species granulose. 



This genus differs from Dorypyge., with which it appears to be most 

 nearly related, in the character of the head ; as far as known the tho- 

 rax and pygidium are essentiall}^ of the same type, as far as fragments 

 of Borypyge can be compared with Bamesella. The pygidium of 

 Daniesella is of essentiall}^ the same type as that of Olenoides.^ and the 

 pleural lobes of the thoracic segments are also of the same type; but 

 the thorax of Olenoides has eight segments and a strong median spine 

 on the axis, while the thorax of Daniesella has twelve or more seg- 



