124 RESEARCH IN CHINA. 



by furrows into four or more segments; border rounded, and bearing five or more 

 spines on each side. 



Surface in the type species granulose. 



Genotype. Damesella blackwelderi Walcott. 



The species referred to the genus are Damesella bellagranulata Walcott, D. 

 blackwelderi Walcott, and D. brevicaudata Walcott. 



This genus differs from Dorypyge [plate 8], with which it appears to be most 

 nearly related, in the character of the cephalon ; the thorax and pygidium are essen- 

 tially of the same type, as far as fragments of Dorypyge can be compared with Dame- 

 sella. The pygidium of Damesella is similar in type to that of Olenoides Meek 

 [plate 8] and Neolenus Matthew [Walcott, 19086, plates 4-6], and the pleural lobes 

 of the thoracic segments are of the same type as those of Neolenus, but the thorax 

 of Olenoides and Neolenus has seven segments and a strong median spine on the axis, 

 while the thorax of Damesella has twelve or more segments and is without a median 

 spine ; from what is known of the cephalon of Olenoides it is of the same character 

 as that of Dorypyge [plate 8]. 



The genus Dinesus Etheridge Jr. [1896, p. 56, plate i, figs. 1-5], appears to 

 be more nearly related to Dorypyge Dames than to Damesella or Teinistion Monke. 

 Its marked characteristics are the elongate, oval glabella, with the small, distinct, 

 antero-lateral and postero-lateral lobes, the small palpebral lobes, and the large 

 pygidium with a spinose border. Only one species is known Dinesus ida Ether- 

 idge Jr. 



The genus Stephanocare, described by Herr Monke in 1903,' was founded on 

 the species Stephanocare richthofeni, subsequently described by me as Damesella 

 chione Walcott [19056, p. 40]. The latter was the fourth species referred to Dame- 

 sella by Walcott. Attention was then called to the difference in the pygidium of 

 Damesella chione (= Stephanocare richthofeni) when compared with the pygidium of 

 Damesella blackwelderi, the type of the genus Damesella. [See plate 7, figs, ijce, 

 of Stephanocare richthofeni Monke, and plate 10, figs. lef, of Damesella black- 

 welderi.] The general contour of the cephalon and the direction of the facial 

 sutures in the two species are much alike, but the spinose margins of the cephalon 

 of S. richthofeni and the sharp spines over the surface of the cephalon, thorax, and 

 pygidium are a strongly marked feature of that species. This character and the 

 difference in the pygidia of the two species indicate different generic relations. 

 With the exception of a few fragments, the thorax of 5. richthofeni is unknown. 



Under the definition of Proparia Dr. C. E. Beecher [1897, p. 198] gives as an 

 original character "Free cheeks not bearing the genal angles," and under Opistho- 

 paria he says: "Free cheeks generally separate, always bearing the genal angles" 

 [1897, p. 187]. In Damesella and Stephanocare the facial suture cuts the postero- 

 lateral margin outside of the genal angle, so as to leave the genal angle on the fixed 

 cheeks, and, at the same time, the spine corresponding to the genal spine in other 

 genera of the order Proparia on the free cheek. In other characters Damesella and 

 Stephanocare belong with the Proparia, and I think that the definitions of the orders 

 Proparia and Opisthoparia need to be modified in relation to the exceptions made by 

 Damesella and Stephanocare in the position of the genal angle on the fixed cheek. 



'When preparing the preliminary notes on the Cambrian faunas of China (Proc. U. S. Nat. Mus., vol. xxix, 

 pp. 1-106, Sept. 1905] in 1905, I had not noticed that Herr H. Monke had published a paper on the 

 Geology of Shan-tung, and described certain Upper Cambrian trilobites. (Beitrage zur Geologic von 

 Schantung. I. Obercambrische Trilobiten von Yen-tsy-yai. Jahrb. konigl. Preuss. Geol. Landesanstalt 

 und Bergakademiezu Berlin, vol. xxin, pt. i, 1903, pp. 103-151.) It was not until February 27, 1906, 

 that the Jahrbuch containing the paper arrived at the U. S. Geological Survey Library. 



