840 
blishing a new genus. There are, 
moreover, in several of the acanthuri, 
bands similar to those from which the 
generic name, eques, is fancifully chosen. 
« The genus trichopus is characterized 
by a compresed body, and ventral fins 
with an extremely long filament. It 
consists of five species, which are distri- 
buted by Cepede into three new genera, 
which -he calls osphronemus, trichodo- 
pus, and monodactylus. As all the first 
four have the long filament of the ven- 
tral fin, and differ only in the number of 
its rays, they may with great propriety 
be united in one genus; but the fifth, the 
monodactylus, wanting that essential 
particular, cannot be a tricopus as long 
as the generic character and generic 
name are suffered to remain. 
The generic name and character of 
gomphosus are taken from the jaws 
whigh are lengthened into a tubular 
snout, and in which the Count Cepede 
fancied he found some resemblance to a 
nail or wedge. It contains two species, 
both natives of the Indian seas. ‘ 
_. Thetwo genera ophiocephalus and lon- 
churus, the former so named from the 
dissimilar scales-of its head as in snakes, 
the latter on account of its lanceolate 
tail, were both introduced by Dr. Bloch. 
They are acknowledged by Dr. Shaw to 
have a greater affinity to the genus. sci- 
ena than any other; and as they agree 
with itin its only essential character, the 
scaly head, we know not why they 
should be separated from it. 
With the generi¢ characters of holocen- 
trus and bodianus we confess ourselves 
completely posed. ‘They stand yerba- 
tim thus ; 
Hotocentrus, 
Habit of the genus perca. 
Gill-covers scaly, serrated, and acu- 
Jeated. 
Scales (in most species) hard and 
rough. 
Bentanus. 
Habit of the genus perca. 
Gill-covers ‘scaly, serrated and acu- 
leated. Bin 
Scales (in most species) smooth. 
They exactly resemble each. other, 
except in the roughness and smoothness 
of their scaleg: and if it were not for 
the unlucky parenthesis which occurs in 
each, the distinction would be plain and 
easy. A rough-scaled fish} with the cha- 
racters possessed in common by.each of 
the genera, we should call an holocentrus; 
a smooth-scaled one, a bodianus. But 
NATURAL HISTORY. 
how are we to determine in what cases 4 
smooth-scaled fish is an heliocentrus and 
a rough-scaled one a bodianus? Of this 
the generic character is totally silent. 
In hopes of finding a clue to guide us 
through the labyrinth, we examined the 
description of the scales in every species 
of the two genera; and behold the re- 
sult of our labour! We found that the 
scales of one of the holocentri are large 
and denticulated at theedges; of seven, 
middle sized; of three, rather» small 
than large; of six, small; of five, very 
or extremely small ; of one, crenulated ; 
of one marked by a white spot; and 
that in nine instances they are not 'men- 
tioned at all. We were told also that 
the scales of one of the bodiani are very 
large with pale edges; of three, middle. 
sized; of two rather small than large ; 
of one, small; of one, tipped with blue ; 
of one edged with silver; and that in 
six they are entirely disregarded. 
We had thus learnt something cons 
cerning the size and colour of the scales 4 
but as far as relates to these, any one of 
the species might be placed with equal 
propriety under either of the genera 5 
and with respect to their roughness or 
smoothness, we were still as much ata 
loss as ever. Conceiving that we must 
have overlooked some part of the de- 
scription, and attributing the oversight 
to the infirmity ef eyes impaired by the 
midnight watchings of many years, we 
first trimmed our lamp; then wiped our 
spectacles ; and then took down a pair 
of greater magnifying power, which we 
use only to mend our pea and on other 
special occasions ; but all to no purpose, 
As our last resort we applied to all our 
fellow critics ‘ in solemn divan as- 
sembled ;”? but still in vain. The dif- 
ficulty was no sooner stated, than every 
one, as if all were animated by one soul, 
rapidly exclaimed, Davus sums nou fEdi- 
pus : itis a knot which none but a god, or 
one inspired by the gods can untie. ‘Tobe 
serious ; generic characters so construct- 
ed are a disgrace to science, . They as- 
sume a scientific appeurance ; but they 
teach nothing. tho esate do Mk j 
The genus trachichthys, aptly but ra- 
ther harshly. so denominated from. its 
strong and. spiny, seales, was instituted by 
Dr. Shaw himself, and -frst described by 
him in the Naturalist’s Miscellany, ‘Che 
large carinated scales of its abdomen, 
connected with,its want.of teeth, afford 
a well discriminated generic character. 
It istound on the coasts of New Holland, 
' 
