Page:Pocock, The Scottish Silurian Scorpion.pdf/3

 "hand" of the chela, and not across its posterior portion as shown in the figure in 'Nature.' One or two other particulars in which I differ from him are referred to in the following pages.

The specimen gives the following measurements in millimetres:—Total length on stone 32·5, actual total length when extended 35·5, trunk 16·5, tail 19.

The Gotland specimen is considerably larger, measuring 62 mm. in total length, the tail being at least 26 mm.

.—Owing to the outward displacement of the chelæ the anterior portion of the carapace is visible between the basal segments of these appendages, and in front of those of the first pair of legs. Its surface is thickly granular, its anterior border lightly concave, as is the Gotland specimen, and its antero-lateral angles subquadrate.

.—In the Gotland specimen no trace of eyes, either median or lateral, is discernible, though the median ocular tubercle of recent scorpions is represented by a relatively large and longitudinally oval elevation, situated in the anterior third of the carapace, and separated from its anterior edge by a space equalling about one half the length of the elevation. Judging from the figure, this tubercle is preserved in its entirety; hence there is no reason to doubt that if eyes had been borne upon it, some trace of them at least would have been preserved.

In the Scotch specimen also there is no sign of the lateral eyes. If, however, as is possible, these organs existed, and were placed behind the level of the median eyes, as is the case in the normal Pedipalpi, and, as is alleged, in the Carboniferous Anthracoscorpii, they would be concealed from view beneath the basal segments of the anterior legs, which on each side overlie that portion of the carapace immediately behind the median eyes. The median eyes are very distinctly represented by a pair of elliptical impressions situated close together, one on each side of the middle line, and scarcely more than their own long diameter from the anterior border of the carapace. There is no evidence that these eyes were