APPENDIX A. ill 
and confluent with the thickened front margin; lateral lobes of 
the glabella short and indistinctly marked, the upper lobe but 
little larger than the rest ; eyes rather small, cheeks prominent 
along their inner edge, posterior angles rounded ? 
The peculiar character of this species, and to which the 
name applies, consists in the absence of any separating furrow 
between the upper lobe of the glabella and the outer margin of 
the cheek ; the glabella thus seems to be drawn out into it on 
either side. 
(‘Tail convex, truly semicireular, the axis obtuse, reaching 
fully four-fifths the length of the tail, and with eight strong 
rings ; the lateral portions with seven distinct furrows, directed 
outwards, and but very little arched, they terminate abruptly, 
and leave a very narrow margin. 
We can only suppose this tail to belong to the large head 
which occurs with it in tolerable plenty ; and as the tail is quite 
that of the genus, we have but little doubt of it.] 
The tail of P. sclerops, as figured by Dalman, is considerably 
like that we have associated with this species, and the head also 
a good deal resembles Swedish specimens which we have seen 
labelled as P. selerops,—they do not however appear identical. 
From P. Odini, our species is easily distinguished by the 
more equal lobes of the glabella, the lower lobes also being quite 
distinct. P. Jamesii, Portlock, appears also to be an allied 
species. 
Loc.—Capel Garmon, Llanrwst, N. Wales, in Cambrian 
rocks. 
P. (Puac.) apicunatus, Sp. Nov. Ref. Pl. 1. G. fig. 17—19. 
Sp. Ch.—Head longer than a semicircle. Glabella elon- 
gate, with nearly parallel sides, and small circumscribed basal 
lobes; the middle pair of furrows faintly marked, the upper 
ones distant, and very oblique; the eye narrow, gently curved, 
and extending along the two upper glabella lobes; angle of cheeks 
nearly square. Caudal shield triangular, nearly equilateral, 
marginate, with a recurved mucro at the apex; axis narrow, 
prominent, with six or seven ribs distinct, lateral furrows four, 
besides the uppermost one, interlined. Thorax......... 2 
In many respects like P. Downingie ; but the long glabella, 
with its very oblique upper furrows and the circumscribed 
basal lobes (like those of the subgenus Portlockia), distinguish 
the head, while the pointed and recurved tip of the longer tail 
well distinguishes that part. There are no other species that 
we think can be confounded with it. This species appears to 
be strictly a lower Silurian one, and is common in the slaty 
rocks of the Bala series, often much squeezed in the direction 
of the cleavage. 
Loc.—Bala; Pwllheli; Berwyns, &c. N. Wales ; Cambrian 
rocks. : 
CaLyMENE PARvirrons, Sp. Nov. Ref. Pl. 1. F. fig. 7. 
Sp. Ch.—Cephalic shield much depressed, semicircular, 
flattish ; glabella narrow, short, subconical, with two lateral 
lobes directed forwards, terminal one small, and not prominent ; 
front margin as long as the glabella, exclusive of the neck-seg- 
ment; the eye distant from the glabella, and placed very for- 
wards, just in advance of it. Cheeks a little more prominent 
than the glabella. 
Distinct from C. duplicata, the tail of which is figured in 
the “ Silurian System” as an Asaphus, by the great projection 
forwards of the front margin beyond the glabella. To that 
species, however, and to Calym. Baylei, Barrande, it is most 
closely allied. 
Loc.—Tai-hirion, near Arenig Fawr, N. Wales, in Lower 
Cambrian. 
Cuerrurus cLavirrons, Dalm. Ref. Pl. 1. G. fig. 9. 
Syn.—Cal. clavifrons, Dalm. Palead. pp. 58, 59. Lovin. Ofv. Ve- 
tenskaps. Acad. 1844. Spherewxochus juvenis, Salter, Mem. 
Geol. Surv. Vol. IT. Pt.1. Pl. 7. figs. 1 to 8 (exclude 3b.) and 
description of tail, ibid. Errata, p. viii. 
The small specimens on our plate shew only the young 
state, when the glabella is more globular than in advanced age. 
In the Memoirs Geol. Sury. quoted above, it is described as 
having no head-spines. We have since seen them in specimens 
which retain the crust:—internal casts frequently mislead in 
this respect, as Burmeister has shewn. 
The full description by Lovén of this species leaves no room 
to doubt that it was a Cheirurus with the ordinary nodular 
pleure of that genus. The tail too, as described by him, agrees 
well with the fragment mentioned in the Errata to the “Survey 
Memoirs,” Vol. II. Prof. M°Coy has very properly separated 
the tail there figured (fig. 3 6.), and also in our Pl. 1. F. fig. 10, as 
distinct ; we had overlooked it in describing the species. 
Loe.—Bala, &e. see p. 154, Cambrian rocks. 
Cysete, Lovén. 
The species of this genus were referred by Dalman to Caly- 
mene, but have since been distinguished by the above-mentioned 
naturalist. Dr Bock, in the “Gea Norvegica,” had indicated 
the group, but not characterized it. It is very remarkable for 
the long pedunculate eyes, twelve rounded thorax segments, 
most of which extend into long points directed back, and for 
the tail, the lateral ribs of which are few and turned back- 
ward, while the axis is cut up into a great number of segments. 
Dr Volborth of St Petersburg has given excellent figures, which 
shew that the facial sutures are much like those of Calymene, a 
small rostral shield being inserted in front. He proposes to re- 
store the name Zethus to the genus, because Pander had so named 
one species ; and I see that Professor M°Coy follows him. But 
Pander had a mere fragment, and evidently intended a species 
of Cheirurus for the type of his genus; his description and 
figures, moreover, are so very uncertain, that his name cannot 
be accepted for either group without creating confusion. 
C. rucosa, Portl. Ref. Pl. 1. G. fig. 8 (magnified). 
Syn.—Ogygia rugosa, Portlock, Geol. Rep. 302. t. 5. fig. 10. 
Caudal shield long, triangular, axis equal to the deflected 
side lobes, with about twenty-eight rings effaced down the 
middle, which is occupied by a broad smooth band; in the 
upper three-fourths these rings at intervals become stronger 
and more prominent, but there are no tubercles down the cen- 
tral line ; side lobes more prominent at first than the axis, but 
towards the end of the tail strongly bent down: lateral ribs five, 
directed longitudinally, each with three or four tubercles; an 
intermediate rib and rugose surface between the upper ones; 
the last two or three from each side uniting beyond the axis in 
a 4-5 spined point. 
b2 
