264 Dr. R. H. Traquair on Fossil Fishes 
in impression on the half of the nodule represented in fig. 1. 
In the diagrammatic outline, fig. 2, the second supraclavicular 
is seen largely covered by the somewhat displaced operculum. 
Both supraclaviculars agree very closely in form and position 
with the corresponding bones in Mesolepis, as seen by com- 
parison with avery beautiful and perfect specimen of JZ. sca- 
laris, Young, kindly lent me by my friend Mr. Ward. Some 
traces of an elongated clavicle are also seen, but not suf- 
ficiently marked for description. 
Fins.—The specimen shows no trace of either pectorals or 
ventrals. The dorsal fin is small, and commences consider- 
ably behind the centre of the arch of the back ; it is composed 
of numerous closely set rays, divided by very frequent trans- 
verse articulations. ‘The most anterior rays are very short, 
but they increase rapidly in length to the ninth or tenth, from 
which the margin of the fin again falls away, so that it becomes 
more fringe-like posteriorly, where the rays are seen also re- 
peatedly to bifurcate. Traces of fine fulcra are seen on the 
anterior margin. On the opposite aspect of the body some re- 
mains of the anal fin are seen—unfortunately only a few broken 
rays; yet from these we may pretty safely conclude that it cor- 
responded in size and position to the dorsal. 
Scales.—Vhe scales of the side of the body are high and 
narrow, diminishing very regularly in size from before back- 
wards. Their form is rhomboidal, the acute angles being the 
posterior-superior and the anterior-inferior. ‘The external 
surface of each presents a well-defined, smooth anterior 
margin, produced downwards into the lower acute angle or 
point of the scale, overlapped by the scale in front, and corre- 
sponding to the thickened articular rib on the internal aspect. 
The latter is by no means strongly marked: it passes above 
into a pointed articular spine of moderate size ; and below, it 
is obliquely bevelled off behind for the articular depression 
which receives the corresponding peg of the scale next below. 
The exposed surface is ornamented by a beautiful granular 
tuberculation, the little tubercles sometimes being arranged in 
lines or coalescing into short ridges, whose direction is always 
more or less across the scale, some tendency to radiation 
downwards towards the posterior-inferior angle being also 
often observed towards the lower part. This tendency of the 
tubercles to coalesce into transverse ridges is most pronounced 
in those scales which are situated more posteriorly (Pl. XVI. 
fig. 3), though I observe it also in one placed just behind 
the lower part of the suboperculum. ‘The two scales repre- 
sented in fig. 3 are from the lateral line, a little in front of the 
origin of the dorsal fin; they are seen to be each marked with 
