(i) 22 Palssontalogia Sinica Ser. B 



Shan, Sbih-mun-chai (Shihmenchai) region near Chingwangtao eastern Chihli province 

 (horizon F3). The formation is Lower Ordovician. 



Ophileta squamosa Grabau (sp. nov.) 



Plate II Figs 3-6 



Shell with sunken spire, the whorls nearly in a plane but asymmetrical, gradually 

 enlarging and in contact except, in some cases, in the last part of the final whorl. 

 Umbilicus very large. Whorls with a gently concave, slightly inward sloping shoulder, 

 limited within by a blunt angulation and without by a rather sharp carina or keel, which 

 is however .not greatly elevated. Outer surface of whorl regularly convex, in such a 

 manner that seen from above the carina is something less than one third of the width of 

 the whorl within the periphery. Lines of growth curving strongly backwards at the 

 carina, forming a pronounced apertural notch at that point. 



On the umbilical side the whorls are gently convex or slightly angular at the 

 center with a pronounced but rounded carina next to the inner margin. On this side the 

 lines of growth are very squamose projecting at regular intervals, in the adult, in the form 

 of small sharp varices. These die away at the outer margin, but continue on the inner 

 carina and along the inside of the whorl to the point of contact with the preceding 

 whorl. Preceding the strongly squamose portion of the final whorl is a part where these 

 squamte have more the appearance of costse and are farther apart (plate II fig 4). This 

 condition is still slightly visible on a portion of the preceding whorl. 



The largest adult individual of this species found (pi. II fig. 6), has a maximum 

 diameter of 38 mm. It is however a much worn specimen, and little can be added to the 

 characters. The width of the final whorl of the aperture is 15.5 mm., the enlargement 

 being rather rapid in the last stage. The growth lines are strongly squamose projecting 

 about. 0.7 mm. from the shell. 



A section of another adult shell has a diameter of 30 mm., but shows only the 

 outer whorl (pi. II. fig. 5), the maximum diameter of which is 12 mm., this being some 

 distance behind the peristome. The outer surface of the shell is regularly rounded, from 

 the keel of the shoulder angle to the margin of the umbilicus which is characterized by a 

 faint rounded keel. The shoulder angle or keel lies about one third the distance in from 

 the periphery of the whorl as seen from above and it forms nearly a right angle. The 



