54 H. W. MARETT TIMS. 
been any upturning of the central and peripheral margins of 
the scalelets. This appears to be easily explained. The 
centrum is the first part of the scale to be formed, while 
there.is comparatively plenty of room in the scale pocket ; 
with increase in size the walls of the pocket become stretched 
and exert an upward “pull” all round the margin of the 
scale; this leaves an impress on the marginal scales in pro- 
cess of formation, and would account for the up-turning at 
the peripheral margin, while the pressure thus exerted in a 
centripetal direction would push the central margin against 
the peripheral border of the scalelets immediately in front 
and bring about the same result, but, as shown in the diagram, 
toa lesser degree. At the growing edge of the scale the 
young scalelets appear to arise from the lateral wall of the 
scale pocket, for they have at first a direction perpendicular 
to the surface of the scale. 
The type of scale above described, or but slight modifications 
of it, is that most generally met with in the Gadide. In G. 
virens, however, there are differences which render the scale 
easily distinguishable (fig. 5). The scalelets have a tendency 
to become triangular in the lateral fields, while in the anterior 
and posterior fields, though quadrilateral, they differ markedly 
from those of the common cod, as will be seen by reference 
to the figures. Moreover, there is no transverse ridge visible. 
Under a high power the scalelets are very clearly imbricated. 
On transverse section, there is no indication of any spine, the 
attached border is implanted in a kind of socket in the upper 
surface of the fibrous layer, and I think there can be but little 
doubt that they represent merely the basal plates of the 
placoid scale, all trace of spines having disappeared. The 
centrum appears to be similar to that previously described. 
One or two other points remain tobe mentioned. In individual 
scales of all species a partial fusion of adjacent scalelets may 
be seen. In every instance which has come under my notice, 
this fusion has been a lateral one. While this condition would 
appear to be the exception in most species, in G. minutus 
it might almost be said to be the rule, for I have not observed 
