558 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxii. 



the beak are intercalated. The more minute surface markings are 

 destro^^ed. 



The dimensions of a pedicle valve are: Length, 7.5 mm.; width, 12 

 mm.; height of area, 1 mm.; convexit}^ 2 mm. 



Remarl's. — The most notable feature of this shell is the conspicuous 

 broadening of the major costse in passing from the beak to the front 

 margin. 



The specific name is in honor of Mr. Bailey Willis, the leader of the 

 Carnegie Expedition to China. 



Formation and Locality. — Ki-sin-ling limestone, localities 20 C and 

 20 B, near Su-kia-pa, province of Ssi-ch'uan. 



CLITAMBONITES CHINENSIS, new species. 



Descri])tion. — Shell broader than long, the hinge line straight, the 

 greatest width at the hinge line or a little in front of it, the lateral 

 and anterior margins describing a regular curve. Pedicle valve 

 strongly elevated at the beak, the surface sloping from the umbo to 

 the anterior and antero-lateral margins with a slightl}^ convex curve, 

 sometimes becoming a little concave as it approaches the anterior 

 margin, the slope to the cardinal extremities somewhat more abrupt; 

 cardinal area large, flat, sloping posteriorly from the hinge line in 

 one specimen at an angle of 102° and in another at an angle of 115° to 

 the plane of the valve, the cardinal margins sharp; delth3^rium rather 

 narrow, closed with a strongly convex deltidium, foramen terminal, 

 encroaching upon the umbo; median septum inconspicuous; muscular 

 impressions indefinite, rather large and flabelliform. Surface of each 

 valve marked by fine radiating costa?, two or three of which occupy 

 the space of one millimeter. 



The dimensions of two pedicle valves are: Length, 15 mm. and 14 

 mm.; width, 18.7 mm. and 16.9 mm.; height of cardinal area, 5 mm. 

 and 5 mm.; greatest width of deltidium, 3 mm. and 2.5 mm. The 

 dimensions of a brachial v^alve are: Length, 16.5 mm.; width, 21 mm.; 

 convexity, 4 mm. 



RemarJis. — This species is represented in the collection by only a 

 small number of specimens, none of which are as well preserved as 

 might be desired. It differs especially from other members of the 

 genus in the terminal position of the pedicle opening, the pedicle 

 apparently having passed through the foramen in a direction con- 

 tinuous with the surface of the deltidium and not at an angle to it, 

 as is usually the case. Apparently this position of the pedicle also 

 modified the position of the spondylium, its surface being nearly 

 vertical to the inner surface of the valve, in consequence of whrdi the 

 median septum becomes essentially obsolete. 



Formation and locality. — Ki-sin-ling limestone, localities 20 C and 

 20 B, near Su-kia-pa, province of Ssi-ch'uan. 



