4^6 JOHAN KliER. [sec. arct. exp. fram 



Description. I. A fragmentary scale (S.I. 25 a), with front 

 side well preserved. (PI. VIII, fig. 1). In the figure the scale is turned 

 up and down in order to show the fine ornamentation with greater 

 effect. 



The diameter of the scale must have heen about 15 mm. Very fine 

 and sharp ribs, which are somewhat interrupted, run in a slightly arched 

 and convergent direction towards the back. 



The inner ones divide forwards. The ribs continue forwards in fine 

 horse-shoe shaped tubercles, which appear to form a narrow zone shaped 

 like a half moon. 



In front of the latter we notice the remains of radial libs, with 

 verv fine tubercles, which most probably have occupied the central part 

 of the portion of the scale that was originally covered. At the sides 

 the latter shows a \ery fine, grained ornamentation, which can also be 

 seen between the ribs. 



One remarkable feature of this scale is the circum.^.tance that the 

 ribs are slightly arched and converge posteriorly, and that they do not 

 appear to be arrangerl cjuite svmmetricallv. 



"■2. On other scales, the surface of \vliich unfortunately is badly 

 preserved, the ribs have a more sub-parallel course and do not appear 

 to be so closely situated as in the case of the previous specimen. The 

 largest scale appears to have had a diameter of about 20 mm. 



Observations. As will be seen, these scales vary to some 

 extent with respect to ornament, but not so much that they cannot be 

 referi'ed to the same species, which pi'obably may be identified with 

 (ihjptolepis paucideiis Ag, The two species, (il. leptopterus Ag. and 

 panridens Ag. which have about the same extent in Europe appear, 

 however, to be difficult to differentiate when we have only isolated 

 >cales. In A. Smith Woodward's Catalogue i, the scales of both forms 

 are described by the same words. Judging from the scales we are in 

 possession of, i. e. Gl. paucidens from the Orkney Islands, and from 

 Paxder's illustration of Gl. leptopterus. the resemblance is greater in 

 the case of the former, which appears to have finer and more numerous 

 ribs than the latter. 



Glyptolepis qiiebece}isis Whit.- is much smaller than the above and 

 is therefore out of consideration. 



1 Vol. II, p. 332 and 336. 



5 Fos. Fislii's of the Devon. Rocks of Canada. Trans. Roy. Soc. Can., Vol. VI. 



