322 DR RAMSAY H. TRAQUATR ON FOSSIL FISH-REMAINS 



mens referable to the genus both from the Mainland of Orkney and from South 

 Ron aid shay. 



Discussion of the geological position of the Old .Red of Shetland I must, however, 

 leave to Dr Flett, and so I proceed to my own proper task, namely, the description 

 of the fish-remains themselves. 



Class PISCES. 



Subclass OSTRACODERMI. 



Order ANTIARCHA. 



Family Asterolepid^e. 



Genus Asterolepis, Eichwald. 



Asterolepis, sp. indet. PI. I. figs. 1-4. 



Description. — Owing to the fragmentary and otherwise badly preserved condition 

 of the remains referable to Asterolepis, it is impossible to give a definition of the species 

 to which they belong, and consequently I refrain from giving it a name at present. 



Fig. 1.— Outline of impression of the greater part of left posterior dorso-lateral plate of Asterolepis, the missing parts 

 given in dotted lines. A anterior, 13 posterior extremity ; a.a., area overlapped by anterior median dorsal plate : b.b., area 

 overlapped by posterior median dorsal plate ; c, part of the area overlapped by the anterior dorso-lateral. The lower part of 

 the plate with the arese overlapped respectively by the anterior and posterior ventro-lateral plates is deficient, and is represented 

 here by dotted lines. Compare with fig. 1 on Plate I. 



Fig. 1, PI. I., is the impression of the outer surface of a plate which is at once 

 identifiable as the greater portion of the left posterior dorso-lateral of a fish belonging 

 to the genus Asterolepis. Its explanation is given in the text-figure above, in which 

 A is the anterior and B the posterior end of the bone, the missing parts being restored 

 in dotted outline. Now along the upper margin is the imprint of a narrow articular 

 area aa, unfortunately broken away a little in the middle. This is the surface over- 

 lapped by the anterior median dorsal plate. Then behind this area and along the 

 posterior-superior margin is a second narrow articular area bb, namely, that overlapped 

 by the posterior median dorsal. Herein we have the proof that the plate belongs to 

 Asterolepis, as in this genus the anterior median dorsal overlaps, as above, the posterior 



