PLATE XXV*. 



(To aid Plate XVII.) 

 ARENIG ROCKS (LOWEST SILURIAN). 



Figs. 1 — 4. Ogygia peltata, Salter. All natural size. From the vertical black 



slates of Whitesand Bay, St. David's, Pembroke- 

 shire. (See Pp. 133—135, and 177.) 



1. „ Intaglio of young S specimen. (Woodwardian Mus., 



Cambridge, case Gh.) 



:2. ,, „ Very perfectly preserved ? form, showing the place of 



the eye, facets of the pleurae, and the short inter- 

 lining furrows of the tail, which differ from 0. 

 scutatrix. (Same Museum.) 



3. „ ,, Wide labrum, broken at the tip. (Cabinet of the late 



H. Wyatt-Edgell, Esq.) 



4. ,, Pull grown ? form (Woodwardian Museum, case G^.) 

 Pig. 5. ^MP^ buUina, Salter. Same Locality and Museum. P. 178. 



All these specimens were collected by H. Hicks, Esq., M.D., St. David's. 



