"232 REPORT—1883. 
having a ‘ bivalved carapace (with distinct hinge-pits), rounded anteriorly, 
‘subtruncate behind, and with the back and front subparallel. The surface 
is smooth, or with only oblique wrinkles near the margins, but with no 
parallel lines of sculpture.’ The body and abdominal appendages were 
unknown to Mr. Salter; but he suggested, in a restoration (op. cit. p. 137, 
fig. 15), a short abdomen, with a lanceolate telson and stylet. Mr. Marr 
has found, in association with Oaryocaris, at the tramway bridge crossing 
the Seiont above mentioned, some small slender spines or pointed styles, 
from about 48, to +3 inch in length, which do not contradict Salter’s ideal 
figure. 
Individuals of Caryocaris Wricutit, Salter, 1863 (op. cit. p. 137, 
fig. 15, and p. 139), measure 1 x 53, inch (Brit. Mus.), 12 x 34, inch 
(Brit. Mus.), and 13 x 45; (5, Mus. Pract. Geol.). 
The test is smooth and thick, somewhat horny in appearance, often 
with light purplish tints, rarely black; the ventral and anterior margins 
are thickened with a raised rim. The anterior moiety is not so much 
contracted as shown in Salter’s illustrations, fig. 15, loc. cit., and the 
figure at p. 21 ‘Camb. Catal.’; nor is there a rim to the dorsal margin, 
as in the first of those figures. The ‘hinge-pits’ have also escaped our 
observation as yet. The most perfect specimens are suboblong and 
elongate, very slightly convex on the dorsal border; more so on the 
ventral, which is elliptically curved, with the convexity slightly greater 
in its hinder than in its front moiety; both ends truncate, one end 
(posterior) rather higher than the other; both vertical, angular at top, 
and neatly curved below; but sometimes modified in direction and form 
by compression. Owing to the relative solidity of the valves this fossil 
is not unfrequently preserved in shape, even when the ‘plaiting’ or 
imperfect cleavage of the pressed schist crosses them at various angles. 
Hence these valves are not nearly so much altered in form in the Skiddaw 
slates as the Hymenocarides are in the Lingula-flags ; yet occasionally, 
when they lie parallel with the superinduced grain of the schist, their 
ends are frayed out, or ‘plaited’ into a mere fringe. A very much 
crumpled specimen was figured by Mr. Salter in the ‘ Geologist,’ vol. iv. 
1861, p. 74, before he described the genus and species in detail. 
Caryocaris Marri, Hicks, 1876 (‘ Quart. Journ. Geol. Soc.,’ 
vol. xxxii. p. 138). 
In the Woodwardian Museum, Cambridge, four specimens, from the 
Upper-Arenig schists on the Nantlle tramway, are labelled C. Marrii, 
Hicks. 1. One, with a black test, compressed, measures 4°, x 33, inch, 
and this has been so squeezed that possibly it is now even narrower than 
it originally was; but the front end is broken and the hinder end is 
fringed off with the ‘ plaiting’ of the schist. This seems to be O. Wrightit. 
It is somewhat thickened at the ventral edge. 2. A similar, but imper- 
fect, specimen, modified with oblique ‘ plaiting.’ Ventral border thickened. 
3. Two imperfect specimens on one slab, one of which, probably 1 inch 
long, is only 2; inch across (high), and has two obscure depressions 
across its middle. One end seems perfect; the other is fringed out. 
This approaches most nearly to Dr. Hicks’s description of C. Marrii. 
4. The other specimen is decidedly an Hntomidella (,°, x 5 inch), rather 
smaller than the Menevian H. buprestis (Salter), and thinner or sharper 
posteriorly in proportion. It may be named Hntomidella Marrit (Hicks). 
A similar form occurs in the Skiddaw slate (2; Mus. Pract. Geol.). 
