64 



This is a species ratlier widely distributed in the northern hemisphere ; 

 the record of its occurrence in the other half of the globe is not at present ac- 

 cessible to the writer. According to Davidson " It has been found in Russia, 

 Estonia, Bohemia, Norway, Spain, the island of Anticosti, Canada West, the 

 United States, etc." It has also been described from Canada East^^ and 

 Sweden.^' Its first discovery in Eastern Asia took place onl\- very recently, 

 when LoKENZ was making a research in the province of Shan-tung. Although 

 he does not give any verbal explication of the species from Shan-tung, his 

 identification is acceptable. He, instead of describing it, gave pictures of the 

 specimens from Europe and America with which the Chinese examples was 

 compared. 



Tlie writer is now to make known the second locality of the species in 

 China, where it was collected together with several other fossils by Mr. S. 

 NoDA of the Imperial Geological Survey of our country. There are several 

 examples of the species at hand that are all very firmly imbedded in a piece 

 of brownish crystalline limestone. It is impossible to take a specimen out of 

 the mother rock, and consequently the detection of the minute characteristics 

 of the specimens is- not very easy. Moreover, the fine surface sculpture is 

 only recognizable with the aid oi a magnifier of somewhat strong power ; for 

 the limestone, being rather coarsely crystalline, is traversed by many small 

 fracture- due to the aggregation of small grains. 



The si)ecimems from the province of Hu-pei that are to be described now 

 are characterized by a convexity of the ventral valve along the median lines, 

 so that they are best compared with such figures as those of Lcptacna scricca 

 var. of jMuRCHisON, and figure lo of Davisiom. If, therefore, the outline of 

 the shell were much less transverse, < r rather longer than wide, this fossil 

 might ha\'e been named Lcptania altcrnata or dcltoidca; only the size is 

 too small. 



The shell is small and transversely semicircular in outline, the hinge-line 

 representing the greatest breadth of the shell, and extending a little beyond 

 the sides of the latter. Cardinal extremities, angular or pointed, but some- 

 times also slightly rounded. Ventral valve, convex, especially so in the 



i) Bigsby: — Thesaurus siluricus, p q6. 1868. 



