2 II. Woodward — On a new King -cr ah 



The head-shield is nearly two-thirds broader than long, the front 

 margin is semicircular and smooth, and the latero-posterior angles 

 are acute and directed backwards. The posterior border of the head 

 is concave, curving slightly inwards near the centre, and backwards 

 towards the latero-posterior angles. 



The glabella is semicircular and has a tolerably well-defined lateral 

 border, separating it from the cheek, but it approaches to, and unites 

 with the border of the head-shield in front. A line (which may cor- 

 respond with the facial suture in Trilobites) passes from the latero- 

 posterior horns of the head-shield, obliquely across the cheeks, and 

 unites with the lateral border of the glabella just where the com- 

 pound eyes are faintly indicated. (See PL I. Fig. \a.) A raised V- 

 shaped lobe, having its apex directed backwards, marks the centre of 

 the glabella : near its apex four minute dots are visible under the 

 microscope, these are most probably the larval eye -spots or ocelli. 

 From the sides of this V-shaped lobe two corresponding lines diverge 

 and unite with the posterior border, whilst the lateral ridges marking 

 the semicircular border of the glabella curve inwards on approaching 

 the posterior border of the head-shield and unite with the median 

 lines near the ocelli. The segments succeeding the head-shield are 

 free, and are strongly trilobed, the ends of the pleurge are all distinct 

 and falcate. The first six segments are thoracic ; the abdomen pro- 

 bably consisted of three segments, followed by an ensiform telson, 

 but only two of these segments are preserved. The breadth of the 

 segments diminishes rapidly backwards, the first thoracic measuring 

 five lines across, whilst the sixth is only three lines, but the depth 

 of each segment is nearly uniform. The form which appears to 

 possess the same number of segments is the genus Hemiaspis, from 

 the Lower Ludlow of Leintwardine, in which we find six thoracic 

 and three abdominal segments ; but, with this exception, our Lanark- 

 shire fossil is a much more Limuloid form than Hemiaspis, reminding 

 one strongly of Mr. Baily's Belinurus regince from the Irish Coal- 

 measures ; from this latter, however, it is also easily separable, both 

 in its general form, and also in the non-anchylosed condition of the 

 abdomen. From the genus Prestwichia it is also separated by the 

 free condition of all its segments. 



Another new form of Limulus (Belinurus Banm) from the Coal- 

 measures of Illinois, U.S., has been described by Messrs. Meek and 

 Worthen,^ for which Mr. Meek has since proposed the generic name 

 of Euproops, in allusion to the anterior position of its eyes.^ This 

 new form is considered by Mr. Meek to be more near Prestwichia 

 anthrax, than to Belinurus, by reason of its anchylosed segments, but 

 he considers that it differs from the former in the comparatively 

 email and quadrangular form of the glabella.'' 



1 Geological Survey of Illinois, 1866, vol. ii. ; Palaeontology, p. 395, PL 32, fig. 2. 



2 Geol. Mag. 1867, Vol. IV. p. 320. 



3 Ilaving, through the kindness of Mr. Prestwich, F.R.S., the type-specimens of 

 his Limulus {Prestwichia) anthrax in my possession, I am the more able to appreciate 

 Mr. Meek's comparison of Euproops Dance with that species. It seems hardly possible 

 to do more than separate them specifically : of their generic identity, I think there can 

 be no doubt. 



