OF THE SPECIES. 63 



Remark. — Count Miinster's Tnnucleus yibbosus {Beitr. Ill, 47, Tabic V, Fig. 2") is probably a 

 fragment of tlic cephalic shield of this, or of the following species. 



2. 0. elUptica : Elongato eUiptica, lobis trunci unispinosis, scuto caudre dccics spinoso. Long. M". 

 Table I, Fig. 4. 



Be/. — Faradoxides quatuor mucronatus, MuRCH. Sil. S^st. ii, 658, Plate XIV, Fig. 10. 

 Acidaspis Brightii, ibid. Fig. 15.? Arges armatus, jiw. Goldf. Nova acta Ph. Med. 

 Soc. Caes. Leop. Car. n. c. vol. xix, P. I, page 355, Table XXXIII, Fig. 1, d, e. 



In a gray limestone of the Eifel, according to a specimen in Sack's collection. Of the 

 cephalic shield there is only a small portion ; but this resembles, as far as it goes, the cor- 

 responding part of the preceding species ; the visible part of the anterior margin, however, 

 is covered with thicker tubercles, and the lobes beside the forehead appear to me to be 

 smaller. The rings of the body (eight) are all present, but only the last two are perfect ; on 

 each there are two small lateral tubercles ; the lateral lobes are smaller than the double 

 ring, each is furnished with two tubercles, and a long spine which issues from the fold ; I 

 did not perceive a second anterior marginal spine. Caudal shield much smaller than in 

 the preceding species, the axis furnished with two rings. The first sends forth a lobe-like 

 swelling to the posterior margin, which terminates at each side in the fourth largest marginal 

 spine ; the three preceding ones are successivel)^ smaller towards the anterior part, the two 

 most central ones (the fifth of each side) as large as the second. 



Remarks. — 1. It is quite certain that the figui-e given by Goldfuss belongs to this species; and 

 is too much unlike his Aryes armatus to allow of its being considered the same species. Murchison's 

 Fig. 10 likewise undoubtedly represents this species, but it must still remain undecided whether Fig. 15 

 is the cephalic shield, as Emmerich and I consider it. 



2. Several authors have recently described Trilobites, which belong to this group of Odoiitop/eum. 

 First of aU, Mr. Locke {Sillim.. Am. Journ.) has described a Ceraurus crassatus. The fragment of 

 Arges radiatus, copied by Goldfuss [Leonh. and Bronn), shows a great similarity with the maxillary 

 shield of this species ; and it also corresponds with the maxillary shield of another species, Ceraurus 

 crenatus, of which Dr. Loven (Ofveis, &c.) has given an elaborate description. The body in the latter, 

 however, consists of niue rings, which denotes a considerable, and even generic difference. Ceraurus 

 globiceps (Portlock, Geol. Rep. of Londonderry , &c.) can with less certainty be identified with the 

 genus we are now considering ; it seems rather to have affinit}' with Ceraurus pleurexanthemus (Green), 

 a species which is supposed by myself and Dr. Beyricli not to be connected with Odontopleura. 



Genus 4. — Arges, Goldf.* 



As I am not acquainted with this genus from actual investigation, I shall here give an 

 abstract of Goldfuss's description. 



Cephalic shield highly arched ; at the centre of the glabella there are two very high, 

 reflexed, diverging spines ; the sides behind the checks are hkewise furnished with a spine, 

 the margin is narrow, the posterior part prominent in an angle, rather curved, equal in 

 length to the joints of the body. Below there is a prominent mouth-plate, much turned 

 downwards, which incloses semicircularly the most anterior part of the head behind the 



* The name of the genus is not well chosen, as there is aheady a genus of Acori described by 

 G. Fischer under the name of Aryas ; other names of the same author arc also subject to similar 

 objections. Harpes reminds one too much of Harpa or Harpte, and Fabricius had already used Brontes 

 for a genus of beetles. 



