BOTLIRIOLEPIS. 109 



anterior median dorsal plate of undoubted Asterolepid type. That he was right in 

 keeping Botliriolepis as a distinct genus was clearly shown by Lalmsen in 1879. 

 Describing a head with a portion of the body attached, as well as some other parts 

 of the body and arms of a species to which he gave the name of B. Panderi, 

 Lalmsen 1 pointed out that the course of the cephalic furrows (lateral line system) 

 was not the same as in Asterolepis ; second, that the post-median plate 

 was different in shape; third, that there was no " os terminate"; fourth, that 

 the articular plates were longer. But when he speaks of the arms being 

 simpler in structure, and we compare his figures, it is quite clear that he had 

 before him only the proximal segment of the limb ; and it must also be noted that 

 in some cases he regarded the grooves of the cephalic lateral line system as sutures, 

 or at least as former sutures, and so very considerably increased the number of 

 bones which he allotted to the cranial shield. 



A contribution to the structure of Botliriolepis, published shortly afterwards by 

 Trautschold, 2 consists largely of corrections of Lahusen's paper in matters of 

 detail. He also formulates the differences between the heads of Botliriolepis and 

 Asterolepis, laying stress on much the same points as Lalmsen, but adding that the 

 angular and opercular elements (Pander) are wanting in the former genus, though, 

 strangely enough, the angular is represented in the diagram which he gives of the 

 head of Botliriolepis. Noteworthy it is that he mentions having found in one 

 specimen a lid or cover to the " orbit " and accurately fitting it. As regards the 

 arms, of which he had no complete specimens, he pointed out certain differences in 

 the arrangement of their constituent plates, and considered it doubtful whether the 

 limb was divided into proximal and distal portions as in Asterolepis. 



G-. Griiricli, 3 in 189], gave a iew notes on specimens of Botliriolepis plates in the 

 Mineralogical Museum at Breslau, in which he noted that Lalmsen had, in his 

 above-quoted paper, put the hinder aspect of the posterior median dorsal plate 

 forwards, and also that Trautschold, in a paper on Coccosteus, had attributed the 

 same plate to a species of the last mentioned genus. 



The discovery by the officers of the Canadian Geological Survey of numerous 

 well-preserved entire specimens of Botliriolepis in the Upper Devonian rocks of 

 Scaumenac Bay, enabled Mr. Whiteaves to give a description, 1 accompanied by 

 excellent figures, of a new species of the genus, to which he gave the name of 

 Pterichihys {Botliriolepis) Canadensis. These Canadian specimens are certainly the 



1 " Zur Kenntniss cler Grattung Botliriolepis" ' Verli. russ.-kais. mineral. Gesell.' (2), vol. xv, 

 1880, p. 136, pis. i and ii. 



2 "Ueber Bothriolejris Panderi, Lalmsen," ' Bull. Soc. Imp. Nat. Mosc.,' vol. It, )>t. 2, 1880, p. 169, 

 pi. ii. 



3 "Ueber Placodermen und andere devonische Fischreste im Breslauer mineralogischeu Museum," 

 'Zeitschr. deutscli. geol. G-esellsch.,' vol. xliii, 1891, pp. 902 — 913. 



1 'Trans. Eoy. Soc. Canada,' vol. iv, sect, iv, 1887. 



