478 PROCEEDINGS OF THE GEOLOGICAL SOCIEIY. [June 7, 



fixed cheek ! Labrura — ? Thorax more than as long again as the 

 head, somewhat narrower in its upper three-fourths than the width 

 of the free cheeks ; but the width of the lower fourth, in consequence 

 of the gi'eatly increased length and thickness of the three or four 

 hindmost pleurae, is much greater, and nearly equal to that of the 

 whole head. The tail is wide and expanded, but narrower than the 

 body. It is widely marginate, and serrated by six or eight marginal 

 spines. 



Anopolentjs Salteri, sp. nov. (Hicks). 



An. 4|- uncice longus, axe lato ; capite magno, margine frontali 

 lato, longispinoso. Glabella angusta, genis cequalibus, frontem 

 attingens, sulcis quatuor brevibus, Oculi longissitni, antic^ gla- 

 bellam, postice cervicem attingentes. Thorax segmenfis 14 {an 

 j>lures?). Pleurce anteriores axe angustiores, spinis brevibus re- 

 curvis ; posticb 3 vel 4, spinis longissimis, curvatis. Cauda semi- 

 circularis, emarginata, serrata, axe 5- vel Q-annulafo, margine 

 lato, sex-dentato. 



Description. — The head — not including the long slender spines, 

 which extend backwards to opposite the ninth or tenth pleurae, and 

 at a slight angle to the general axis — is semicircular, with an even 

 outline, and bounded by a strong wide margin, which is only slightly 

 narrower in front. The glabella occupies about a third of the width 

 of the head, being broadest across the frontal lobe. It reaches far 

 forward, where it is slightly contracted, and separated from the front 

 margin only by the deep furrow which surrounds the head. It is 

 raised a little above the level of the cheeks, having rather deep 

 axial furrows intervening. Well marked glabella-furrows divide it 

 into a frontal lobe, three lateral lobes, and a neck lobe, but are not 

 complete across in this species, which thus differs at a glance from 

 A. Henrici. The frontal lobe is large, wide, and bounded below by 

 the supplementary or first pair of furrows*. These are short, less 

 distinct than any of the others, and sinuate, arising from the 

 sides of the glabella at its broadest part, and reaching to about 

 one-fourth of its width ; their inner extremities nearly touch the 

 second pair of furrows, thus forming small triangular lobes on either 

 side. The third or median furrows are well marked, equal to the 

 fourth or ocular pair, but less strong than the basal and neck 

 furrows ; they arch gently forwards and stretch equally across with 

 the ocular and basal, leaving centrally an intervening, narrowed, 

 elevated space, which extends in this species all down the middle 

 of the glabella. The ocular and basal furrows run inwards 

 nearly in a straight line (the former being perhaps a little curved) ; 

 but the latter is much deeper and wider than the former, and 

 equal to the neck furrow, which is the only one continued direct 

 across. The neck and basal lobes are of equal breadth ; both exceed 

 the middle lobe, which again is broader than the upper or third lobe. 



* There are only a few genera in which the anterior or supplementary pair 

 is found. 



