658 



TRILOBITES OF THE UPPER SILURIAN ROCKS. 



that these markings ought to constitute a specific difference only, for I am aware that this sort 

 of sculpture can seldom be a generic distinction. I have merely added them to the generic 

 character provisionally. They are seen in specimens from Staffordshire as well as in the beau- 

 tiful head PL 7 bis. f. 3. belonging to Mr. B. Bright, which was found on the western slopes 

 of the Malvern Hills. The under surface of this head (PI. 7 bis. f. 3Z>.) also shows how the fine 

 furrows (lines of growth ?) conform separately to the outline of the different parts of the 

 head. 



Loc. Hay Head Lime W orfcs, near the village and beacon of Barr, Staffordshire ; near 



Brand Lodge, Malvern Hills, the residence of Mr. Bright, near Presteign. 

 Paradoxides Brongniart. Entomostracites paradoxides (Wahlenberg) . Olenus (D aim an). 



Gen. Char. — "Corps deprime' non contractile. Flancs beaucoup plus larges que le lobe may en, 

 Bouclier presque demi-circulaire ; trois rides obliques sur le lobe moyen. Point de tuber eules, 

 oculiformes. Abdomen a douze articulations. Arcs des flancs, abdominaux et post-abdomi- 

 naux, plus ou moins prolonge's hors de la membrane qui les soutient." 



Brongniart established this genus, and I therefore retain his name. Without entering into 

 a detail of characters, it may always be recognised by the ends of all the lateral ribs termi- 

 nating in deflected points, some of which extend in spikes beyond the tail. 

 Paradoxides bimucronatus (n.s.), f. 8. 



Our specimen differs essentially from any published by Wahlenberg, who first figured the 

 genus, or from the figures of Brongniart or Dalman, in having a sharp, two-pronged tail. The 

 large, incurvated, flanking spines are also wider apart than in the P. Tessini, Brong. PI. 4. f. 1. 

 (the Olenus Tessini, Dalm. tab. 6. f. 3.), which it more nearly resembles. 

 Fig. 9. is probably the body of Paradoxides bimucronatus, f. 8., being found in the same slabs 

 of limestone. The lateral lobes of the body present curiously sculptured plates, that almost 

 give it the appearance of being divided into five lobes. 



On examining the structure of the segments of trilobites, we find a great variety of sculpture. 

 The sculpture in f. 9. is very remarkable. We may observe, that the further the rough sculp- 

 ture reaches from the middle lobe, the less the animal must have had the power of moving 

 and coiling itself up. See Homalonotus Ludensis, PI. 7« f« 4. and Calymene Blumenbachu, 

 PI. 7- f* 6. A reference to a lobster's tail will best explain this sort of structure, which is 

 strongly developed in our f. 9. and has been alluded to in p. 653. 



Loc. Wenlock Limestone of the Malvern Hills, where it was found by Mr. B. Bright. 

 Paradoxides quadrimucronatus (n.s.), f. 10. 



This beautiful little species, from the cabinet of Mr. Stokes, differs from the P. spinulosus, 



Brongn. PI. 4. f. 2. [Olenus spinulosus, Dalm. tab. 6. f. 4.) both in general form and in having 



a four-pronged instead of a simple rounded tail. 



Loc. Dudley. 

 Acidaspis, Nobis, (axi;, mucro, a<T7nj, scutum.) 



Gen. Char. — Capitis scutum marginatum, antice subtruncatum, trituberculatum : tuberculo 



medio postice in mucronem desinente. 

 Acidaspis Brightii (n.s.), PI. 14. f. 15. 



Although most unwilling to multiply names, the very remarkable form of the head or shield 



of this trilobite, the posterior end of its central lobe projecting over the body in the form of a 



stomacher, and rendering it totally distinct from any published figure, induces me to propose 



it as a new genus. 



