|ii!(LIBRARYl5 



THE OTTAWA IIATURALIStV^ ^ 



Vol. XV. OTTAWA, MARCH, 1902. No. 12. 



ON THE GENUS PANENKA, BARRANDE, WITH A 



DESCRIPTION OF A SECOND SPECIES OF THAT GENUS 



FROM THE DEVONIAN ROCKS OF ONTARIO. 



By J. F. Whiteaves.* 

 (With one Plate.) 



In the sixth volume of the " Syst^me Silurien de la Boheme," 

 which was published in two parts in 1881, Barrande proposed the 

 name Pmienka for a genus of lamellibranchiate bivalves from the 

 Silurian rocks of Bohemia, and described and figured no less than 

 231 species of that genus. These species are all ornamented with 

 radiating ribs, which give them a certain general but superficial 

 resemblance to recent shells of the genus Cardium. But, upon 

 closer examination it will be seen that in many of the Panenkas 

 the ribs are unequal in size and irregular in their distribution, and 

 that their valves are usually longer than high. Their test, also, is 

 said to be thin, and their hinge line to be entirely devoid of teeth 

 properly so called. On the other hand, in the typical species of 

 Cardnim the ribs are exquisitely regular in their size and arrange- 

 ment ; their valves are higher than long ; their test comparatively 

 thick, and their hinge line provided with both cardinal and lateral 

 teeth. Dr. Paul Fischer, in his " Manuel de Conchyliologie," 

 places the genus Panenka in Rudolph Hoernes' family Proe- 

 cardiidce, which consists exclusively ot palaeozoic genera and 

 species. 



Four years later, in 1885, Professor James Hall described and 

 fio-ured. or enumerated, seventeen species of Paneiika from the 

 Devonian rocks at several localities in the United States, in 

 volume V, part I, Lam.ellibranchiata II, of the " Palseontology of 

 the State of New York." And, in 1891, the present writer 

 described and figured an unusually large and coarsely ribbed 

 species of the genus, from the Corniferous limestone at St. 



*Communicated by permission of the Acting Director of the Geologfical 



Survey Department. 



