PAIJEOXISCIDJE. 
519 
P. 2026. Head, abdominal region, and some of the scales of the 
caudal region, vertically crushed and showing the dorsal 
aspect; Lyme Eegis. The tubercular ornamentation of 
the cranial roof and the anterior two-thirds of its pair 
of longitudinal sensory canals are well exhibited; and 
there are indications of a series of small ossifications in 
the axial skeleton of the trunk—evidently the expanded 
bases of the arches. Of the fins, only the right pectoral 
and the dorsal are preserved. There is no median series 
of enlarged dorsal ridge-scales; but the squamation of 
the anterior dorso-lateral region is well preserved, and 
the ornamentation is distinctly exhibited. The ridges 
upon these scales are extremely delicate and frequently 
interrupted, appearing as series of elongated tubercles. 
Egerton Coll. 
39860. Imperfect fish, 0'365 in length, ventro-lateral aspect, 
showing all the fins except the dorsal, and confirming 
many of the characters mentioned above ; Lyme Eegis. 
Fur chased, 1866. 
38734. Head and trunk of small fish, ventral aspect, imperfectly 
preserved and wanting all the median fins. The pelvic 
fins and one of the pectorals are shown. Purchased , 1865. 
P. 3509. Imperfectly preserved fish, wanting the extremities of the 
head and tail; Lyme Eegis. This specimen is noticed by 
Agassiz, and described by Egerton as the type of Thris- 
sonotus colei. The fact, however, that the scales are com¬ 
paratively smooth and exhibit concentric structural lines 
is due to the preservation of the fossil in a hard nodule; 
while the supposed great relative length of the anal fin 
seems to be partly a false appearance, caused to some 
extent by the displacement of the scales and its hinder 
fin-rays, and by the loss of the distal extremities of the 
anterior rays at the margin of the nodule. Traces of the 
dentition and the characteristic ornament of the jaws and 
cranial roof are distinguishable. Enniskillen Coll. 
P. 874. Crushed remains of a large head. Egerton Coll 
P. 3487 g. Caudal fin. Enniskillen Coll . 
