THE SKELETON OF THE BLACK BASS. 
315 
pare them in the following manner: One head is to be macerated in warm water until 
all the soft parts can be removed and the bones separate from each other, except those 
in the cranium. Each bone should be removed by itself, laid out to dry in a relative 
position it occupied in the skull, and identified if possible. For this latter operation 
the second skull is intended, and this one should also be partially macerated, but only 
so far as to moderately soften the tissues; then by the most careful dissection, all of 
these should be removed, and the entire osseous structure of the head left precisely as 
it is in life, in so far as the bones are concerned, the latter being held together only by 
their ligaments. This prepared skull is then properly dried. The third head, prepared 
exactly like the second, is longitudinally sawed in two by means of a very fine saw, 
passing to one side of the crest of the supraoccipital. By means of these two halves 
we are enabled to study the osseous parts of the interior of the brain case and the 
bones at the anterior extremity of the skull. 
Fig. 3 of the present paper, as well as the illustration of the skull of the large- 
mouthed black bass in fig. 2, will give an idea as to how the bones are normally related 
to each other, and as shown in the heads of the two species of Micropterus prepared 
by the second method. Fig. 21 of my memoir on Amia calva shows the head, or rather 
the cranium, of a yellow perch ( Perea flavescens) longitudinally bisected in order to 
bring into view the bones in the brain case. 
As has been stated, if the head of this bass is allowed to macerate in water for a 
sufficient length of- time all the more loosely attached bones, including the occipital 
ribs (fig. 1, oc. r.), will come away and separate from each other. This leaves the cranium 
all in one solid piece as shown in fig. 1. This, as lias likewise been said, is composed 
of its own bony cranial segments, which require more protracted maceration to sepa- 
rate them. This cranium , and many fish possess one a good deal like it, is of a 
pyramidal form, the base being formed by the occiput and the apex by the vomer (ro), . 
which is here produced downwards as a prominent beak, being rounded in front, and 
thickly studded with fine teeth upon its inferior surface. 
A very noticeable feature of the cranium are the orbits. These are large and in 
no way separated from each other by an osseous medio-longitudinal plane standing 
between them. Above, they have a wide, arched roof, concave from before, back- 
wards; while below there is but the median rod, composed principally of the vomer 
(vo.) and the parasphenoid ( Pr . *S’.). Other bones entering into the bounding walls of 
the orbits are the frontals above (Fr.), the prefrontals anteriorly (Pr/.), the alisphenoids 
(As.), and the postfrontal (Ftf.). On top of the cranium, behind, and occupying its 
hinder half, there are five conspicuous crests, a median one and two lateral ones on 
each side. These are well shown in fig. 1, and have been fully described in my Amia 
memoir. They vary greatly in the crania of different species of fishes, being entirely 
absent in some species and very prominent in others. 
In the common cod ( Gadus ), for example, the median crest is thick, strong, and 
high, and produced far backwards and to the front to a point over the center of the 
orbits. Again, in the black s'ea-bass (Centropristes striatus ), of which I have prepared 
one or two perfect skeletons, these crests are more as in Micropterus, but by no means 
exactly the same, as these two species belong to very distinct families. At the back 
of the cranium there are to be noticed chiefly the circular, conically concave facet 
for the atlas vertebra, with above it, one upon either side, the pair of zygapophysial 
facets for the corresponding ones on the same vertebra. These have above them 
