OF THE SPECIES. 75 



Facial suture indistinct ; I can perceive only a slight indented arch, which issues from 

 the place at which the border and central shield meet together. This line turns towards 

 the eye-tubercle, and separating from the latter at the posterior part, makes another turn 

 with a sharper curvature, over the posterior half of the sides to the angle, which is formed 

 by the open posterior margin and by the lobes of the angle. 



Body many-jointed (above twenty), the axis very convex, narrowing posteriorly, but 

 elsewhere quite as broad as the lateral lobes ; both these are short, the latter at first hori- 

 zontal, slightly furrowed, bent much downwards at the end, and obtusely pointed. 



Caudal shield not known. 



Zow//(y.— Upper Silurian and Devonian strata of the Eifel, the Fichtelgebirge, Bohemia, 

 and Ireland.* 



Remark.^. — 1. Of this genus I have before me only a single cephalic shield, but this is for the 

 most part well preserved ; it lies in a yellowish, liver-brown limestone, probably the same in which is 

 also found Odontopleura ovata, and has, like the latter Ti-ilobite, preserved its real shell, partially at 

 least. This shell is punctated with little indentations at all parts where it has not been damaged, but 

 the punctation is luieven, so that the largest indentations are situated immediately at the circumference 

 of the real cephalic shield, where the flat border proceeds from it ; and they decrease in size from this 

 point both towai-ds the inner and outer part. A fine mai-ginal ridge runs quite round the open margin 

 of the border, and before it there is a row of larger indentations. The eyes are wanting in the speci- 

 men I possess, but their places are indicated. 



2. Count Sternberg first described a species of this genus as TrUobiles unyula {Verhandl. d.vaterl. 

 Mus. 1833. 52, Fig. 1), in which at least twenty body rings were perfectly distinct. From this Goldfuss 

 constituted the genus {Nova act. Phys. Med. Soc. Caes. Leop. Carol, nat. cur. vol. xix, p. 1, 358, Table 

 XXXIll, Fig. 2, a, b, c), and gave a more accurate account of the organization, which was, howe\cr, 

 ah-eady known. According to him there arc twenty-eight body rings. Count Älünster endeavoured to 

 enrich the genus by new species [Bcitr. z. Pctref. Parts III and V) ; but it appears to me that he has 

 often merely taken individual differences for specific characters. This is the more likely since all his 

 specimens, as also those of Sternberg, probably consist of mere impressions, without any remains of the 

 shell. At present, therefore, I can admit only the following species :t 



H. tmgula : Limbo scuti cephalici antice latiori, punctate ; punctis internis majoribus, foraminulosis. 

 Long, sine corp. l>^-2", cum corp. 2-23^". Table I, Fig. 11. 



Otarion pygmaeum, Münster (/. c. V, 115, Table X, Fig. 11), appears to me to have been a very 

 young, but mutilated indi-iddual; Otar. eleyans (ibid. I, Table X, Fig. 2) an older individual, but also 

 mutilated; Harpes macrocephalus, Goldf. (/. c. 359, Table XXX, Fig. 2, a, b, c), and the figure given 

 in this work, represent full-grown, perfect individuals. 



Goldfuss's description is detailed and correct ; and as my specimen is not so well preserved, I will 

 repeat his words : 



"The inverted egg-shaped body is depressed, but the head is considerably elevated, and 

 occupies more than a third of the length of the whole animal. Its circumference is semi- 

 circular, and it is suiTounded by a broad margin, which at the anterior part is horizontally 



* Portlock [vuh Keport, &c.. Tab. V) has published figures which prove beyond a doubt that the 

 genus Harpes belonged to that group of Trüobites capable of rolling themselves into a ball. It cannot 

 therefore be brought iuto auy near relation with Trinucleus, as Portlock supposes, and as Loven has 

 endeavoiu-ed to prove {Ofvers, &c. 105). 



t I no longer hold this view, and am now much rather inclined to regard both Portlock's species 

 as perfectly distinct ; and I also am willing to admit at least two of Count Miiuster's species. That 

 represented in Table V, Fig. 19, 23, is one of these ; and the other is that marked Fig. 20, 22. The 

 former reminds one of Harpes Flanaganni, of Portlock (/. c. 268, Plate \, Figs. 5-7) ; the latter, of his 

 H. Doranni (ibid. 267, Plate V, Fig. 4). Count Sternberg's figure more resembles the former than the 

 latter species. 



