REPORT OF THE DIRECTOR I919 



87 



color lines been referred to Kionoceras darwini (Billings) 

 by the authors, but since these lines are also but brown color lines 

 and the shell is smooth, it should more properly be identified with 

 Orthoceras trusitum. Also this specimen seems to pos- 

 sess the brown color bands on one side only. 



The zigzag markings of the Bohemian species of Cyrtoceras men- 

 tioned above as well as the beautifully scalloped and wavy color 

 bands which Barrande has so well figured of Crytoceras par- 

 vulum (pi. 481, figs. 1-15), C. zebra (ibid. figs. 16-20); C. 

 c y a t h u s (ibid. figs. 21-24), C . p a r v u 1 u m (pi. 504, figs. 1—45) 

 etc. pass entirely around the shell. These transverse color bands 

 thereby contrast with the longitudinal color markings of Orthoceras 

 here described. 



Fig. 26 



Fig. 27 



Fig. 26 Cyrtoceras Zebra Barrande ; fig. 27 C 

 Barr;fig28 C. decurio Barr. (All after Barrande) 



Fig. 28 



p a r V u 1 u m 



Likewise, do all the species of Cyrtoceras here cited, strongly 

 contrast, by their breviconic and curved shells with wide open 

 apertures with the long, slender, fairly orthoceraconic shells with 

 longitudinal markings. 



It is quite obvious that both color markings and form of conch 

 are in both groups of shells in perfect harmony with their mode of 

 life, in Orthoceras with a crawling habit, in which the conch is 

 dragged behind; in the breviconic species of Cyrtoceras with a 

 crawling habit in which the shell is carried obliquely or fairly 

 upright, and as suggested by the position of the hyponomic sinus 

 on the convex side, with the apex pointing forward. 



