﻿CEPHALASPID2E. L99 



Genus DIDYMASPIS, Lankester. 



[Geol. Mag. vol. iv. 1807, p. 152.] 



An imperfectly known genus, with two anterior dorsal shields, 

 differing only from those of Auchenaspis in the absence of promi- 

 nent cornna, and in the relatively greater size of the hinder shield. 

 A large ventral shield is opposed to the latter. 



Didymaspis grindrodi, Lankester. 

 [Plate IX. figs. 7, 8.] 



1807. Didymaspis grindrodi, E. R. Lankester, Geol. Mag. vol. iv. 



p. 153, pi. viii. figs. 4-7. 

 1870. Didymaspis grindrodi, E. R. Lankester, Fishes Old Red Sandst. 



pt. i. (Pal. Soc), p. 59, pi. xiii. figs. 1, 2. 



Type. Shield ; Oxford Museum. 



The type species, of small size, the maximum antero-posterior 

 measurement of the two shields being about 0-025, and their maxi- 

 mum breadth 0*018. The two dorsal shields firmly united, the 

 anterior somewhat smaller than the posterior, and the latter taper- 

 ing, though abruptly truncated behind ; the line of junction between 

 the two shields describing a double curve, the produced lateral 



Fig. 30. 



Didymaspis grindrodi, Lank. — Outline of shield, after Lankester. 



angles of the anterior portion embracing the posterior portion, but 

 not diverging from it, while in the median line the anterior shield 

 is produced into the posterior to a small extent. Superficial orna- 

 mentation consisting of irregularly arranged fine tubercles ; a faint 

 median keel in the hinder half of the posterior shield. 



Form. fy Loc. Lower Old Red Sandstone : Ledbury, Hereford- 

 shire. 



