(i) 90 Palasontoloyia Sinica Ser. I> 



shorter axis measures 15 mm. At this point the siphuncle is situated about 4 mm. from 

 the convex side and has a diameter of 4.5 mm. being approximately circular in section. 

 The increase of the shorter axis in another specimen (Plate VIII, fig. 7 cat. no. 2) is from 

 9 mm. to 13 mm. in the space of 17 mm. giving a rate of tapering of 1 in 4.25. In this 

 specimen the siphuncle has a diameter of about 4 mm. at the lower end, not changing 

 appreciably throughout. Its distance from the outer margin of the upper end of the 

 specimen is about 4 mm. but it is only about 2 or 2.5 mm. from this margin at the lower 

 end. In a specimen from Chaokouchuang (Plate VIII, fig. 8) with a shorter diameter of 

 about 10 mm. at the base, the siphuncle is 2 mm. from the outside and has a diameter of 

 3 mm. or a little more. The transverse diameter here is about 11.5 mm. Fourteen 

 millimeters higher, these diameters are 12 and 15 mm. respectively, giving rates of 

 tapering of 1 in 7 and 1 in 4 respectively. In a- sectioned specimen from Shantung 

 (Plate VIII, fig. 10) the diameter of the siphuncle is 4 mm. where that of the shell is 15 

 mm., and it is 2.5 mm. from the convex side. In form it is strongly nummuloidal and 

 filled with stereoplasm deposited in rosette form as in Actinocems. There is a narrow 

 subcentral endosiphuncle. 







Septa from 2.6 to 2.75 mm. apart, of moderate curvature, and with comparatively 

 little stereoplasm in the camera;, this being most extensively developed on the convex 

 side. 



This species differs from the American Middle Ordovician (Chazy) species mainly 

 in its excentric siphuncle, and longer camene in the young. It has much less stereoplas- 

 mic deposit in the chambers than has C. champlainense Ruedemann, and it curves less 

 than does C. boycii Whitfield. A short section of the shell might easily be mistaken for 

 a small species of Actinoceras. 



HORIZON AND LOCALITIES: In the Machiakou limestone of early upper Ordovician 

 (Black River) age at Tangshan, Machiakou, and Chaokouchuang, all in the Kaiping 

 basin of eastern Chihli province, (Collections: T. C. Wang, H. C. T'an and Y. C. Sun 

 respectively). Also from Chingchuang, Ning-yang district, Shantung province (coll. V. 

 K. Ting). 



The specific name is given in memory of the late Dr. Fritz Freeh of Breslau 

 Germany, to whom we owe the fifth volume of Richthofen's great work on China, and 

 whose labors have done so much towards increasing our knowledge of the invertebrate 

 fossils of China. 



