485 
from Achanarras Quarry , Caithness . 
there being five on the right and only four on the left. They 
are proportionally narrower than in Megalichthys , but not so 
narrow as in Osteolepis. 
12. Cheirolepis Trailli , Ag. — Two specimens of this from 
Achanarras are in the Museum of Science and Art, and one in 
the collection of the Geological Survey, and I also observed 
some fragments of the same species in the ddbris of the quarry. 
I have no hesitation in referring these specimens, the first of 
the genus ever observed in Caithness, to the same species as 
that which is so common in the Orkney as well as in the 
Moray-Firth beds. 
13. Palceospondylus Qunnii , g. et sp. n. (fig. 4, magnified). 
— This is hitherto the only novelty which has turned up in 
the quarry, and it is of excessive in- 
terest, though unfortunately it must Fig. 4. 
take its place among the fossil fishes <L 
incertce sedis. It might indeed be asked, 
Where is the evidence that it is even a 
fish ? though there is no doubt of its ^ 
being a Vertebrate. 
Tli is little organism varies from 1 
to 1^ inch in length, of which measure- j 
ment the head occupies about a fifth. S 
Little can be made out of the struc- M 
ture of the head, which looks like a JF‘ 
flat crushed mass of bony bais j it Palceospondylus Gunnii , 
is a little longer than broad, with a Traq., twice nat. size, 
slight lateral hour-glass constriction, 
rounded in front and truncate behind ; from the front two 
small, short, pointed processes project, one on each side, 
like a pair of little feelers, while behind a little shield-like 
body passes back over the first three or four vertebras. Nothing 
at all comparable to jaws, upper or lower, can be seen. The 
vertebral axis, which passing back from the head becomes 
attenuated to a fine point posteriorly, is composed of distinctly 
ossified and separate vertebral centra, which, however, appear 
to me to be hollow or ring-like, as in Chondrenchelys &c. In 
the anterior tw r o thirds of the vertebral column the neural 
arches are distinctly seen in the type specimen, but they are 
not furnished with prominent spines ; but in the latter third 
very slender obliquely-directed spines make their appearance 
both neurally and haemally. 
Not the smallest trace^ of limbs has been seen in any 
specimen. 
