02 



OLD RED SANDSTONE FISHES. 



previous restorations of Pterichthys as well as of Asterolepis, I gave the outline of 

 the external margin of the ventral aspect of the posterior ventro-lateral plate as 

 becoming slightly excavated or concave posteriorly. This was due to those outlines 

 having been taken from natural internal casts of the plates in question, the fact 

 being thereby overlooked that, the bone being considerably thicker at that place, 



Fig. 51. 



Fig. 52. 



Pig. 51. — Restored figure of Pterichthys Milleri from the dorsal aspect altered from that on p. 65, 

 Fig. 34, by the addition of the small narrow plate in front of the median of the head and the 

 rectification of the elements of the forearm. Lettering as before. 



Pig. 52. — The same from the ventral aspect, amended from Pig. 35, by the rectification of the 

 elements of the forearm and of the outline of the posterior ventro-lateral plates. Lettering as before. 



the exterior configuration does not exactly correspond. So that when the bone is 

 completely preserved, the margin in question is seen to sweep round in an unbroken 

 curve as now represented 



Reverting now to Jaekel's recent paper, there is a point in his account of the 

 exoskeleton of Pterichthys concerning which I must emphatically record my dissent 

 from his conclusions. According to my description of the body-carapace of 

 Pterichthys and other Asterolepidae, the upper part of the side (Fig. 36, p. 65) 



