178 



SILURIAN TRILOBITES. 



falcate. The groove ends abruptly a little way within the tip. In the tail eight furrows 

 cross the axis, the last three not quite complete. The interlining furrows are certainly 

 not so long nor so distinct as in our former description and figure. 



The following is the new form which occurs with 0. peltata at St. David's : 



Ogygia bullina, n. sp. PI. XXV*, fig. 5. 



0. plana, modica, biuncialis, capite semicirculato, fronte latiori, aiigulis — Glabella 

 pyriformis, ad basin anpistata, lobisqiie basalibus injlatis ; gence absunt. Oculi prope 

 (jlabellam, in medio capite positi. Thorax axe angustissimo, pleuris rectis, fulcra ultra 

 medium posito . Cauda ? Labrum ? 



A neat species, which was sent by my correspondent Henry Hicks, Esq., of 

 St. David's, from the beds at Whitesand Bay. 



The form is broad-oval. We have but the head, without free cheeks, and eight or 

 nine of the body-rings, but there is enough to show that the fossil is quite new. The 

 head is broader than a semicircle, and has a wide, coarsely striated front (the squamate 

 striae are not visible in our figure) ; a pyriform glabella, inflated in front ; strong basal 

 obliquely oval lobes, projecting beyond the neck of the glabella, and separated from it by 

 rather strong lines. Neck-furrow of the glabella tolerably strong, and much broader 

 than that beneath the cheeks. Eye-lines above and below the eye widely diverging ; the 

 eye short, and placed about halfway up the head, but even closer to the glabella than in 

 0. peltata, which species accompanies it. Beneath the eye the suture curves so largely 

 out that it must nearly reach the angle of the head. We have not the free cheeks, and 

 of course do not know anything of the spines ; I suppose these must have been short. 



Thorax with a very narrow and somewhat prominent axis, which is about half as wide 

 only as the flat pleurae, and these are nearly direct ; the slight fulcrum, placed beyond the 

 half of the pleura, being scarcely an angular bend at all. The facet, however, is very 

 distinct and sharp-edged. Fine curved transverse striae cover closely the glabella, and are 

 traceable on the axis of the thorax. The much coarser striae on the fascia beneath the 

 pleura3 range up to the fulcrum, but not within it. 



Locality. — Arenig Rocks. North-east angle of Whitesand Bay, St. David's (Wood- 

 wardian Museum, Cambridge). The species should be sought for in the same beds on 

 Ramsey Island. 



My lamented friend Mr. II. Wyatt-Edgell found a new Barrandia in the black shales 

 of Abereiddy Bay. (For this genus, see p. 137, &c.) We are only able to give a 

 woodcut ; and it is a melancholy pleasure to introduce a description in this work from 

 his pen. 



