314 PROCEEDINGS OF THE GEOLOGICAL Society. [Apr. 19, 
the ventral plate and the ventro-lateral plates of the right side have 
been removed so as to display the interiors of the dorsal plate and the 
anterior and posterior lateral plates of that side. On the left side the 
ventro-lateral plates remain in situ. The posterior ventral plates and 
the thoracic plates with the pectoral fins attached are also shown. 
The head is partly dislocated, but the outlimes of some of the plates 
are seen, as also two circular pomts which may possibly be the cap- 
sules of the eyes. The posterior portion of the fish is nearly entire, 
and shows the arrangement of the scales, and the position and cha- 
racters of the dorsal and caudal fins. ‘The specimen is from Gamrie. 
There is doubtful evidence of a third species at Gamrie ; the specimens 
may possibly be young individuals of one of the other species, as 
they are all of small size. j 
Genus PAMPHRACTUS. 
PAMPHRACTUS HYDROPHILUS. id Red, Tab. 4. figs. 4, 5, 6. 
This appears to be the figure of the dorsal superficies of a Pterich- 
thys. It should therefore be restored to that genus, under the de- 
signation of Pterichthys hydrophilus, the name originally given by 
Agassiz to this specimen. 
Genus HOMOTHORAX. 
? Old Red, Tab. 31. fig. 6. 
A view of the ventral surface of the above. 
HomotTHoRAx 
W oodcut, fig.1, p. 305.—Interior | Woodceut, fig. 2.—Ventral 
projile. view. 
a. Dorsal plate. e, e. Anterior ventro-lateral plates. 
5. Posterior dorsal plate. J, f- Posterior ventro-lateral plates. 
ec. Anterior lateral plate. g.- Ventral plate. 
d. Posterior lateral plate. h, h. Posterior ventral plates. 
e. Anterior ventro-lateral plate. i,z. Thoracic plates. 
f. Posterior ventro-lateral plate. k, &. Pectoral fins. 
h. Posterior ventral plates. 1. Glenoid cavity. 
z. Thoracic plate. 2. Ditto, in section. 
k. Pectoral fin. 
1, 1. Marginal rings. 
2. Horizontal rib. 
3. Diagonal rib. 
PLaTE X.—Pterichthys quadratus. 
. Dorsal plate. I. Eyes? 
. Anterior lateral plate. m. Head. 
. Posterior lateral plate. n. Dorsal fin. 
Anterior ventro-lateral plate. o. Caudal fin. 
. Posterior ventro-lateral plate. 1,1. Marginal rings. 
. Posterior ventral plates. 2. Horizontal rib. 
Thoracic plates. 3. Diagonal rib. 
Pectoral fins. 
Pre we Aas 
ee ee ee 
