24 0 SILURIA. [Chap. X. j 
found in the Old Red Sandstone, and also in the lower beds of the Carbonife- 
rous rocks of Scotland, whence they were first described by Dr. Hibbert *. 
Mr. Henry Woodward has of late enriched the list of Silurian organic remains 
by recognizing the existence of Cirripedes among the fossils of the Wenlock 
Limestone of Dudley, De Koninck's Chiton Wrightianus having proved to be 
really a new form of this suborder. Several specimens have been found. It is 
the earliest known of the pedunculated Cirripedes, and has been named Tur- 
rilepas by Mr. Woodward f. 
In the first edition it was affirmed that in the true Bone-bed of Ludlow no 
remains of Fish, save those of a few placoid genera, were to be met with. Even 
here their remains are very scanty, some of those few which were formerly re- 
ferred to the class having been removed, as stated at p. 134, to Crustaceans. 
But those remarkable heads called Pteraspis (PI. XXXVII. f. 9-11) are still to 
be referred to Fishes, according to Professor Huxley, who has ascertained that | 
there is no essential difference between their structure and that of Cephalaspis {. j 
There are at least two species of these old anomalous Ganoid ? fishes in the 
Ludlow rock itself. Both have been found near Ludlow, — one in the grey 
Ludlow rock, by Dr. JohnHarley, of King's College, London; the other, by Mr. 
A. Marston, in the Bone-bed of Ludlow. 
The first of these, which is of a plain oval form, and with only fine longitu- j 
dinal striae, is probably P. truncatus, Huxley and Salter, Foss. 68. f. 1 j the ' 
other, a broader species, is P. Banksii, ib. f. 2. Both of these (here figured) 
Fossils (68). 
Fishes (Pteraspis) from the Ludlow Rock and Passage-beds §. 
1. Pteraspis truncatus, Huxley and Sal- 
ter, from the ' Passage-beds,' Kington. 2. 
P. Banksii, Huxley and Salter ; an orna- 
mented species, snowing, too, the cervical 
spine. From Upper Ludlow rock at Lud- 
low : the same species occurs in the ' Pas- 
sage-beds.' 
were discovered by Mr. Banks in the ' Passage-beds ' of Kington in Hereford- 
shire (p. 138) ; the latter species was also found near Kidderminster by the late 
Mr. George Roberts, together with the Pterygotus before mentioned. The two 
species of Cephalaspis in the shale at the Ludlow Railway-Station (p. 139) 
must not be forgotten. The occurrence in true Ludlow strata of one, if not two, 
* Trans. Eoy. Soc. Edinb., 1st ser., vol. xiii. 
pi. 12. 
t Quart. Journ. Geol. Soc. vol. xxi. p. 486. 
I Mr. E. E. Lankester's description of the 
scales of Pteraspis, and of the shape of the per- 
fect head-shield, forms a valuable contribution to 
our knowledge of this interesting Fish. Quart. 
J ourn. Geol. Hoc. vol. xx. p. 194. 
$ The fish-fragments figured, above, as well as 
those illustrated in PI. XXXVI. under the name 
Pteraspis, require a note of explanation as to the 
name. They received that name from Dr. Kner 
(see H aidinger's Abhandl. vol. i.) in 1847, who 
referred them to Cephalopoda. They have since 
been regarded by some as Crustacea, though Agas- 
siz placed them among Fishes of the genus Ce- 
phalaspis. 
In a memoir read before the Geological Society 
(Quart. Journ. vol. xiv. p. 267), Professor Huxley 
definitely included them in the class of Fishes. 
I may here observe that my friends the Eev. W. 
Symonds and the late Eev. F. Dyson, knowing the 
position in which these Fishes ought to occur, 
discovered them in their own Malvern district, 
and have detected the principal species in the 
Lower Cornstones of the Old Eed Sandstone at 
Cradley. 
