110 F, R. Cowper Reed—Girran Crustacea, ete. 
‘they are completely fused with the cephalic shield, and the presence 
of free segments behind is conjectural. Indeed, the genus has been 
placed by some paleontologists amongst the Cirripedes, and it is 
possible that it is really allied to Lepas. The dorsal edge of the valves 
is never well seen, but is more incurved than the ventral. 
There is a somewhat longer and narrower form of valve represented 
cat Balelatchie, with the dorsal and ventral margins straighter and nearly 
parallel, but otherwise possessing precisely the same characters as the 
above, so far as can be seen in the two imperfect examples before me. 
It probably belongs to another species, and bears much resemblance to 
‘the insufficiently known A. longa, Barrande (op. cit., p. 579, pl. xxvi, 
figs. 42-45). 
PinwocaRis. cuRvATA, sp. noy. (Pl. IV, Figs. 5-7.) 
- The single species of this peculiar genus hitherto known was first: 
‘described’ by R. Etheridge, jun., from the Balclatchie Beds of the. 
Girvan district, but was subsequently treated more fully by the same 
author in conjunction with Professor Nicholson in their ‘‘ Monograph 
-on the Silurian Fossils of Girvan,” vol. i, 1880, pp. 207-210, pl. xiv, 
figs. 17-20. Since then Professor Rupert Jones and Dr. Henry 
Woodward have discussed it on two occasions* and published figures 
-and accounts of the Balclatchie specimens in Mrs. Gray’s collection, 
and of one English example from the Upper Silurian of Kendal. 
There are seven specimens of a member of this genus, from the 
Starfish Bed, Drummuck Group, of Thraive Glen, which Mrs. Gray 
has sent me for examination. The horizon is new, and the 
characters of the fossil are such as to warrant its specific separation 
from the Balclatchie form which was named P. Lapworthi. The name 
curvata may be proposed for it on account of its peculiar shape. 
Diagnosis. — Carapace bivalved. Valves flattened, triangularly 
obovate and elongate, posteriorly curved upwards; anteriorly broad, 
widening to middle of valve, then tapering rapidly into long narrow 
produced posterior portion. Pseudo-umbo situated at about one-third 
the length of the shell from anterior end. Dorsal margin in front 
of pseudo-umbo obliquely inclined downwards, slightly concave, 
thickened internally ; margin behind pseudo-umbo curved, markedly 
concave upwards. Anterior margin short, regularly rounded, semi- 
elliptical. Ventral margin strongly convex to a little behind middle 
of valve, then curving rapidly upwards and slightly concave. Posterior 
portion of valve narrow, elongate, tapering to blunt end, gently convex, 
not corded, but marked with weak submedian groove along its length. 
Surface of valves marked with regular striations concentric to ventral 
margin, centreing on pseudo-umbo, and ending abruptly against pre- 
umbonal dorsal margin. In internal casts there is in each valve 
a short slit proceeding obliquely forwards from the umbo at a small 
angle to the margin, and immediately in front of it is another but 
BR Etheridge, jun.: Proc. Roy. Phil. Soc. Edinb., vol. iv (1878), p. 167, 
pl. ii, figs. 3-5. 
2 Jones & Woodward: Mon. Brit. Palzoz. Phyllocarida (Paleont. Soc.), pt. ii 
(1892), pp. 118, 119, pl. xv, fig. 24; id., Gzoz. Maa., Dec. IV, Wel II (1895), 
pp. 542 -045,. PL. XV, Figs. 6 5-10. ; 
