Vol. 60.] EDESTUS IN THE COAL-MEASURES OF BRITAIN. 3 



obtained, also from near Moscow, a more perfect specimen with a 

 large part of its grooved basal segment: thus more firmly establish- 

 ing the occurrence of the genus in Europe. 



In was in 1886 that Dr. Henry Woodward [14] described the 

 remarkable ichthyodorulite from the Carboniferous rocks of Western 

 Australia, to which he gave the name of Edestus Davisii. The 

 specimen differed in several points from the forms hitherto referred 

 to Edestus, more especially in its deeper curvature and in the 

 larger number of its denticles ; but Dr. Woodward was correct in 

 regarding it as nearly related to Edestus, although it is now placed 

 in a distinct genus. 



Another species which, on account of its large size, received the 

 name of Edestus giganteus, was described by Newberry [17] in 

 1889, from the Coal-Measures of Decatur, Macon County (Illinois) ; 

 and in 1898 Dr. Bashford Dean [20] gave an account of another 

 much-curved form, under the title of Edestus Lecontei, from the west 

 of the Rocky Mountains, in Nevada. 



In 1899, Dr. Karpinski [21] published his detailed memoir on 

 the Edestidae and on a new genus, Helicoprion. Several examples 

 of these ' spiral saws ' had been found in the ' Artinskian stage ' 

 (Permo-Carboniferous) near the town of Krasnoi Ufimsk, in Eastern 

 European Russia, a little west of the Urals. These extraordinary 

 tooth-bearing spirals still remain an unsolved problem, notwith- 

 standing the lively discussion to which Dr. Karpinski's memoir has 

 given rise, and which continues to the present time, several eminent 

 workers abroad and at home having expressed their views on the 

 subject [see 27-31]. Not the least important of these contributions 

 were the papers published by Dr. Eastman in 1901 and 1902 

 [22-26]. In one of these [24] a new genus, Campyloprion, is 

 established for certain fossils closely allied to Helicoprion. In this, 

 and the subsequent memoir, Dr. Eastman describes the Orodus-like 

 jaw of Campodus, with its somewhat compressed and enrolled 

 symphysial series of teeth, which are regarded as of Cestraciont 

 type, and are thought to indicate the principle of enrolling of the 

 teeth on or near the symphysis, which culminated in the ' spiral 

 saw ' of Helicoprion ; Edestus and Campyloprion showing inter- 

 mediate stages, in which the teeth were broken off or worn away, 

 instead of being retained and rolled into a spiral. 



The presence of Helicoprion in the Carboniferous rocks of Japan 

 has been made known by M. H. Yabe [32], and I am indebted to 

 Dr. A. Smith Woodward for this reference. 



The specimen, found by Mr. Pringle at Nettlebank, was, when it 

 first came into ray hands, in several pieces, and much of it was still 

 hidden in the hackly, dark limestone. 1 The fossil itself being very 

 brittle, the greatest care was necessary for its development ; it is 

 now, however, in a condition to show its complete form, with the 

 exception of the point of the tooth, which was not found. 



1 Dr. W. Pollard, F.Gr.S., who has kindly examined the rock, says that_it ia 

 an impure limestone, containing some magnesia and ferrous carbonate. 



b2 



