THE SCALES IN SOME TELEOSTEAN FISH. 55 
any scale in which it was absent, usually the fusion being 
considerable. This would seem to be a point of some im- 
portance, for if we imagine a lateral fusion of the small scale- 
lets to take place throughout, we then approximate to the 
typical clupeoid scale, which is composed of excentric imbri- 
cated rings. 
On the other hand, if the spines present in the scalelets of 
the G.callarias be more pronounced and slightly more per- 
pendicular in direction, we have the spines of a ctenoid 
scale. In the latter the spines are present only in the 
posterior field, in the same position as they are most evident 
in the cod. The earlier tendency to disappearance in the 
anterior field is probably due to the imbrication. 
One further point: the radiating lines of scalelets at a 
certain distance from the circumference become replaced by 
double lines. This is probably in adaptation to the increased 
circumference of the scale. Still nearer the margin one of 
the four again bifurcates (if the scale be placed with the 
anterior pole towards the observer, it seems to be always 
the line to the right which thus becomes divided). This is 
only marked in the posterior field, though elsewhere the same 
takes place, but is neither so striking nor does it appear to 
be of such regularity. 
Clupeoid Scale.—The scales of the adult herring, sprat, 
and pilchard have been examined, but, with the exception of 
some unimportant differences, such as relative size, there is 
but little to distinguish between them ; consequently, the des- 
cription of the herring scale here given applies equally to the 
sprat and pilchard. 
The excentric markings seen on the clupeoid scale is limited 
to the anterior portion, the posterior uncovered part being 
quite smooth, each excentric line roughly describing a semi- 
circle. Neither in stained nor unstained specimens are any 
radiating lines visible such as are seen in the scales of the 
cod. Further, the excentric series of markings presents a 
considerable degree of uniformity in passing from the centre 
of the scale to the periphery. In all the scales examined 
