756 MR. F. E. C. REED ON THE LOWER PALEOZOIC [NoY. 1 899, 



genus (or subgenus).^ It comes from Stage 2 of the Tramore 

 Limestones of Tramore. Its features are closely similar to those of 

 M. limbata, Aug., from the Orthoceras-limestone,^ and it possesses 

 the same shape, the posterior pair of nodules, the striated border, etc. 

 of that species. Eut the central portion slightly widens in front 

 and is not so distinctly marked off from the anterior wings. More- 

 over, its whole surface is ornamented with curved striae, arched 

 backward and parallel to the side-borders. 



Hecjalaspis, sp. y. 



In my collection there are some large parabolic pygidia without 

 -any trace of an axis, axial rings, or pleurae. They are in an im- 

 perfect state of preservation, but the surface is seen to be flattened 

 and smooth, with a slightly excavated border which, beneath the 

 crust, shows an ornamentation of concentric striae particularly 

 strong on the upper and inner edge. The anterior margin of the 

 pygidium is imperfect. The whole shape is rather more pointed 

 and elongated than that of Asaplms gigcis (De Kay) as figured by 

 Salter, and the absence of all trace of an axis completely dis- 

 tinguishes it. 



The estimated length of one specimen is 45 mm,, and its width 

 from 50 to 60 mm. 



This form is found in Stage 3 of the Tramore Limestones in 

 Newtown Cove and at Dunabrattin (Geol. Surv. Coll.). The speci- 

 mens from the last-named locality are in a somewhat better state of 

 preservation, and are slightly more elongated, one measuring 52 mm. 

 in length and the same in breadth. Angelin's ^ Megalaspis rudis 

 resembles this form in the absence of any trace of an axis and of 

 ^ny furrows. 



Associated with this form there is a head-shield which probably 

 belongs to it. Prom the specimens, which are unfortunately imper- 

 fect, we are able to judge that it much resembled A. gigas as figured 

 by Salter. But the eyes are placed rather more forward, and the 

 axial furrows behind them are quite wanting. There is a fine 

 specimen of the head, minus the free-cheeks, measuring 35 mm. in 

 length, in the Geological Survey Collection from Dunabrattin, and 

 the present author has one from Newtown Cove. 



AsAPHus (Ptychopyge ?) RADiATTJS, Salt. var. 



There are several specimens of pygidia in the Geological Survey 

 Collection from the Tramore Limestones of Dunabrattin, labelled 

 Ogygia, which agree in all their principal characters with Salter's 

 A. radiatus.^ But they differ in being rather less transverse in shape, 

 and in possessing nine instead of eight furrows on their pleural 



^ Brogger, 'TJeber die Ausbild. Hypost. skand. Asaphiden,' Bih. t. Kong. 

 fivensk.Vet.-Akad.Haiidl.vol. xi (1886) No. 3 p. 40. 



2 Brogger, ' Die Silur. Etagen 2 u. 3/ 1882, p. 77 & pi. xii, fig. 10. 



3 ' Pal. Scand.' 1854, p. 50 & pi. xxvii, fig. 5. 



* Monogr. Palseont. Soc. ' Brit. Trilob.' p. 157 & pi. xviii, figs. 1-5. 



