Africa, Central -- Description and travel; Africa, East -- Description and travel; Natural history -- Africa; Slave trade
Belonging to the Order Ganoidei, this fish is with equal certainty
referable to the family Palæoniscidæ, but its _genus_ is more a
matter of doubt owing to the fragmentary nature of the specimen.
Judging from the form and thickness of the scales, I should be
inclined to refer it to _Acrolepis_, were it not that the dorsal and
anal fins seem so close to the tail, and so nearly opposite each
other; here, however, it may be remarked that the disturbed state of
the scales affords room for the possibility that the original
relations of the parts may not be perfectly preserved. I have,
however, no doubt that, as a _species_, it is new; and as you have
been the first to bring fossil fishes from those regions of Central
Africa, you will perhaps allow me to name it _Acrolepis_ (?)
_Drummondi_.
No. 2 is a piece of cream-colored limestone, with numerous minute,
scattered, rhombic, striated, ganoid scales, which I cannot venture
to name, though I believe them to be palæoniscid. Associated with
these is a small portion of the margin of a jaw, with numerous minute
sharp conical teeth. But also lying among these minuter relics is a
scale of a much larger size, and clearly belonging to another fish.
It measures 1-4 inch in height by the same in breadth; its shape is
rhomboidal, having an extensive anterior covered area, and a strong
articular spine projecting from the upper margin. The free surface
is brilliantly ganoid, and marked with furrows separating feeble
ridges, which pass rather obliquely downwards and backwards across
the scale, and terminate in eight sharp denticulations of the hinder
margin. A little way off is the impression of the attached surface
of a similar scale, and there are also two interspinous bones,
probably belonging to the same fish.
This is probably also a palæoniscid scale, resembling in shape those
of _Acrolepis_, but it is rather thinner than is usually the case in
this genus. It has also considerable resemblance to some of those
scales from the European Trias, named by Agassiz _Gyrolepis_. Though
it may be rather venturesome to name a species from such slender
material, nevertheless we may, provisionally at least, recognize the
scale as _Acrolepis (?) Africanus_.
Nos. 3 and 4 are small pieces of the same limestone, covered with the
minute striated palæoniscid scales referred to above.
No. 5 is a piece of gray micaceous shale, with scales of yet a fourth
species of palæoniscid fish. One conspicuous scale unfortunately,
like all the rest, seen only from the attached surface, is 1-4 inch
in height by nearly 1-6 in breadth; it is tolerably rectangular in
shape, having a well-developed articular spine and fossette. Part of
the scale is broken away at the anterior margin, the impression
brought into view showing that the covered area is narrow, and
indicating that the free surface is striated with rather sharp ridges
passing obliquely across the scale. The posterior margin is finely
denticulated.
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