532 John M. Clarke — Bunaia Woodwardi. 



pentameral division is clearly accompanied by remains of the five 

 pairs of legs, the mouth orifice, and, as it seems, the chelate first legs 

 folded down close alongside the mouth. 



We illustrate here in connexion with these features a head of 

 Bunodes lunula, the Oesel species, showing a similar arrangement of 

 the five pairs of legs and, in addition, what appear to be the lateral 

 thickenings of the glabellar ridges. This is a specimen from which 

 the very thin epidermal film has been removed. Further, the head- 

 shield of Bunaia displays more than that of Bunodes in its thickened 

 margins and extended cheek-spines. Patten believed that antennse 

 were present in Bunodes, and so restored it, but we find no evidence 

 of these structures in Bunaia. 



In our specimens the chief difference of Bunaia from Bunodes is in 

 the structure of the abdomen. In the latter there are six broad 

 segments followed behind by three narrow ones. In Bunaia this 

 structure appears to be somewhat different. The cephalon or head- 

 shield is followed behind by narrow segments of which seven or 

 eight can be counted, with possibly one missing. These seem to be 

 of somewhat unequal length and to be longitudinally ridged, but 

 without lateral flanges. Our knowledge of this structure is 

 restricted to a single example and is subject to modification. In 

 one of the three specimens there is a broad detached smooth spine 

 lying alongside the head, which may have been the telson, though 

 apparently pretty large for the species. 



The measurements are as follows : width of carapace, 8 mm. ; 

 estimated total length of animal, inclusive of telson, 23 mm. 



The specimens of Bunaia Woodwardi are from the Bertie Water- 

 lime of the Salina Group at East Buffalo, N.Y. 



EXPLANATION OF PLATE XIV. 



Bunaia Woodwardi, sp. nov., J. M. Clarke. 



FlG. 1. — A weathered exterior of a head-shield showing the triangular central 



area or "glabella" and the five pairs of lateral lobes crenulating the 



surface and corresponding to the legs beneath. x 8. 

 FlG. 2. — The interior of a head-shield with five pairs of radial appendages and 



evidently a sixth pair at the central mouth. The light-coloured lines on 



the right-hand radial areas are elevated linear ridges which appear to be 



parts of the appendages themselves, and it is thought that the broad dark 



areas may include both legs and gills. X 8. 

 Fig. 3. — A crushed and defaced head-shield with a postabdomen of ridged 



segments. X 8. 

 FlG. 4. — A telson spine which lies close to the specimen Fig. 1 and, it is 



thought, may belong to this species. x 8. 



All the foregoing are from the Bertie Waterlime (Silurian) at the East 

 Buffalo, N.Y., quarries. 



Bunodes Lunula, Eichwald. 1 

 FlG. 5.— An exfoliated carapace from the Silurian of the Island of Oesel, 

 showing the broad dark bands left by the six pairs of cephalic appendages 

 and also the central divergent ridges which seem to be the interior 

 projections of the ridges of the " glabella ". X 3. 



1 Dr. d'Eichwald, Archiv fur die Naturk. Liv.-Ehst.- und Kurlands, erste 

 Serie, vol. ii, pi. ii, figs. 12-13, 15, pp. 378-82, Dorpat, 1859, 8vo. 



