RHIZODONTIDJB. 
359 
Type. Imperfect fishes ; British Museum and Forres Museum. 
The type species, attaining a maximum length of about 0-3. Head 
with opercular apparatus contained about four and a halftimes in the 
total length ; parietal region equal to the fronto-ethmoidal in length, 
and the upper part of the anterior extremity of the snout covered 
with separate polygonal plates ; jaws much elongated. Pelvic fins 
arising in advance of a point midway between the operculum and 
the extremity of the tail; dorsal fins higher than long, the first 
smaller than the second, and the latter about equal in size to the 
opposing anal. Scales small. 
Form. §• Loc. Lower Old Bed Sandstone : Nairnshire, Banffshire, 
and Orkney \ 
50104. 
P. 340. One of the type specimens figured by Agassiz, op. cit. 
pi. xxi. a. fig. 3 ; Lethen Bar, Nairnshire. Egerton Coll . 
Fish, in counterpart, showing portions of several head and 
opercular bones, the clavicles, and fragments of the fins ; 
Lethen Bar. The inner ridge upon the scales is very 
prominent. Purchased , 1879. 
41891. Head and abdominal region of small fish; Tynet Burn, 
Banffshire. Purchased , 1870. 
43014. Small fish, in counterpart, showing the obtusely lobate 
pectoral fins and portions of the pelvics, dorsals, and anal, 
but wanting the caudal fin ; Tynet Burn. 
Purchased , 1871. 
43271. Small fish showing portions of the fins ; Tynet Burn. 
Purchased , 1871. 
36071. Scattered scales and various bones of a large fish; Tynet 
Burn. Purchased , 1861. 
P. 4045. Large well-preserved fish, 0‘3 in length, in counterpart; 
Gamrie, Banffshire. The head is vertically crushed, and 
one side of the counterpart exhibits the cranial roof 
from the inner aspect, while the other gives an imperfect 
inner view of the principal jugulars. The parietal and 
fronto-ethmoidal regions of the cranial roof are well sepa¬ 
rated by a transverse suture ; and there is a median suture 
between the frontals, marked at one point either by a large 
excavation on the inner surface of the closely apposed bones, 
or by a foramen, such as exists in Osteolepis and Diplopterus. 
1 Fragments from the Devonian of Livonia are also assigned to this species by 
E. von Eickwald, Leth. Eossica, vol. i. (1860), p. 1564. 
