﻿34 BRITISH FOSSIL CRUSTACEA. 



The largest of these measures about four feet in length and some fifteen inches in 

 breadth, 1 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 Carmyllie, 

 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. 



The next largest example is from the Turin 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, is 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 (p), 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 (o), with its 

 central lobe (e), is seen in situ overlying the first and second body-segments. The trunk is 

 nearly entire, and only slightly compressed along the right side. The telson (t) 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 overlying 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. 2 



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 



1 It was probab'y considerably broader, as one side is very much plicated along the margin for almost 

 the entire length of the body. 



2 See Mr. Powrie's valuable paper upon the geology of this district, with descriptions of the Fish 

 Remains, &t\, discovered by the author, ' Quart. Journ. Geol. Soc.,' 1861, vol. xvii, p. 534. 



