﻿GEPHAJiAarmzE. 196 



45970 a. Two cornua from " Troclms bed," Downton Bridge. 



Lightbody Bequest. 



P. 3247. Cornu from Bone-bed in Upper Ludlow, near Ludlow 



Enniskillen Coll. 

 P. 5844. Cornu; Downton Sandstone, Kington. 



Presented by John Edward Lee, Esq., 1885. 



The following specimen is doubtfully assigned to an unknown 

 species of Eukeraspis : — 



45969. A long, narrow fragment of smooth fibrous bone, denticu- 

 lated on the thin long margin, and noticed under the 

 name of Plectrodus by Egerton, Quart. Journ. Geol. Soc. 

 vol. xiii. (1857), p. 288, pi. x. fig. 2; Downton Sand- 

 stone, opposite the Paper-Mill, near Ludlow. The den- 

 ticles are slender, pointed, and longitudinally grooved, and 

 are arranged in two series, the inner being largest and 

 widely spaced. The bone has more completely the aspect 

 of a jaw than the cornua of the typical Eukeraspis. 



Lightbody Bequest. 



A fragment of denticulated bone from a Lower Palaeozoic Boulder, 

 found near Danzig, is also described as Plectrodus mirabilis (?) by 

 F. Roemer, Palseont. Abhandl. vol. ii. (1885), p. 359, pi. xxxi. 

 fig. 26. [University of Breslau.] 



Genus AUCHENASPIS, Egerton. 



[Quart. Journ. Geol. Soc. vol. xiii. 1857, p. 286.] 



Syn. Thyestes, E. von Eichwald, Bull. Soc. Imp. Nat. Moscou, 1854, 

 pt. i. p. 108 (inaccurate definition). 



Postero-lateral angles of shield more or less produced into acute 

 cornua, not exceeding the shield in length. Body depressed, ovoid 

 in transverse section ; three or four series of dorso-lateral scales 

 fused into a continuous plate immediately behind the shield. 

 Tuberculations in part very large. 



Having had the privilege of examining some of the original ex- 

 amples of Thyestes described by Eichwald, Pander, and Schmidt, in 

 St. Petersburg, the present writer finds the orbits as distinctly 

 marked in the Oesel fossils as in the typical shields of Auchenaspis 

 from Herefordshire. Moreover, some of the specimens of Auchen- 

 aspis egertoni discovered by Mr. Piper in the Ledbury Passage Beds 

 exhibit traces of the very large tuberculations and the transverse 



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