34 BRITISH FOSSIL CRUSTACEA. 
The largest of these measures about four feet in length and some fifteen inches in 
breadth,! and is preserved in the Arbroath Museum, having been presented to that 
institution by Lord Dalhousie. It was obtained from his lordship’s quarries at Carmayllie, 
in Forfarshire. 
The specimen is preserved as an intaglio upon a large slab of Devonian sandstone, 
into which the detached body fits, as into a mould, exhibiting both the upper and under 
surfaces of eight of the body-segments united together. The head is wanting, but a 
portion of the base of a foot-jaw (maxillipede) belonging to the right side remains; the 
operculum or thoracic plate is also partially preserved. 
‘he next largest example is from the Turm Hill Quarries, Forfarshire, and 
was presented to the British Museum by James Powrie, Esq., F.G.S. It is but 
very slightly distorted, and exhibits the natural rounded form of the dorsal surface 
of the body in an admirable manner. ‘Ten of the body-rings are preserved 
united, measuring twenty-seven inches in length by about ten inches across the widest 
segment. 
The third, which is figured on PI. I, fig. 1, 1s twenty-three inches in length and seven 
inches in its greatest breadth; it was obtained from the same locality as the one last before 
mentioned. In this specimen the ventral surface is exposed to view, exhibiting the 
metastoma or post-oral plate (y), preserved upon the slab nearly in its normal position, 
with a portion of the left maxillipede by its side, suggesting the probability of the head 
being also concealed in the matrix beneath. The operculum, or thoracic plate (0), with its 
central lobe (c), is seen ¢w situ overlying the first and second body-segments. The trunk is 
nearly entire, and only slightly compressed along the right side. The telson (¢) is 
detached from the last segment. These three specimens are destitute of heads and 
appendages (save the two median appendages mentioned), but they serve well to illustrate 
the general form of the body at three different periods of growth. The first and largest 
would, if restored, represent an individual about five feet in length; the second one about. 
three feet six inches; and the third about two feet. They are all from the “ Arbroath 
paving-stone.” The fourth, and smallest, but by far the most perfect specimen hitherto 
met with, was obtained by Mr. Powrie from the indurated shale overlymg the ‘“‘ Arbroath 
paving-stone.” From this shale, which is very finely laminated, and breaks up throughout 
into cuboidal fragments, Mr. Powrie has also obtained many new and interesting species 
of Fishes.” 
The specimen is figured of the natural size at Plate II, fig. 1, and, although the dorsal 
surface is exposed, the whole animal has been so flattened out and compressed that some 
of the organs of the mouth are seen, as faint impressions, through the integument of the 
" It was probably considerably broader, as one side is very much plicated along the margin for almost 
the entire lengtin of the body. 
2 See Mr. Powrie’s valuable paper upon the geology of this district, with descriptions of the Fish 
Remains, &c., discovered by the author, ‘ Quart. Journ. Geol. Soc.,’ 1861, vol. xvii, p. 534, 
