P E R C A. 
(hoals the coafts of Sumatra; three inches long; fcales 
fmall, denticulate, dotted with brown. Head fmall, 
wedged, the nofe and front brown ; iris brown-filvery, 
mouth fmall; the lower jaw a little longer. Lateral line 
parallel with the back, a little bent down at the end of 
the dorfal fin. Pedtoral and ventral fins yellow, the reft 
brown, ftreaked with yellow. 
78. Perea trutta, the trout-perch : gill-cov.er in four 
pieces, ending in a blunt procefs ; noltrils double ; co¬ 
lour blackifh brown. Six rays in the membrane of the 
gills, 5Vin the dorfal, 13 in the anal and pedtorals, 6 in 
the ventrals, 18 in the tail. This and the following were 
communicated to Cepede by Bofc; they both inhabit 
Carolina. The trout-perch has a fmall-elevation on the 
fnout; the mouth opens very wide ; lower jaw the long- 
eft, both armed with a great number of very fmall teeth ; 
the tongue is flelhy; two rows of fmall teeth on a trian¬ 
gular plate in the roof of the mouth ; laminae fimilarly 
armed above and below the entrance of the gullet. The 
eye is large, with a yellow iris; the fides of the head co¬ 
vered with fmall fcales. The lateral line runs parallel 
with the back ; and there is a furrow to receive the fpines 
of the dorfal fin ; the ventrals are united by a membrane. 
The belly is white. This-fpecies is plentiful in all the ri¬ 
vers of Carolina, where it is called trout . Length near 
two feet; flelh firm and well-tafted. 
79. Perea iridea, the iris-perch : gill-cover in four 
pieces, terminating in a blunt procefs : tail rather lunate ; 
a large oval black fpot edged with white at the extremity 
of the dorfal fin, and a little black fpot at the hinder an¬ 
gle of the operculum. In the dorfal fin rays, in 
the anal, 9 in the pedlorals, -J- in the ventrals, and 24 in 
the tail. A little groove on the head before the eyes ; the 
teeth are very fmall; the ventral fins united, as in the 
preceding. Lefs than fix inches long; colour brown 
grey, fpotted and dotted with darker brown ; a delicate 
pale yellow line acrofs moft of the fcales; two Hoping 
lines, and feveral fmall black fpots, on the dorfal fin. 
This fpecies is alfo very numerous in the frefii w'aters of 
Carolina, and are particularly fought after in the fpring. 
Sod Perea trifurca, the trident perch : tail-fin three-lo- 
bed ; feven blue bands acrofs the body. In the dorfal 
fin rays, pedlorals 16, ventrals \, anal -j\-, tail 20. 
Oblerved at Carolina by Dr. Garden. It is prettily va¬ 
riegated, efpecially the head and the ventral fins ; gullet 
yellow ; gill-covers very finely toothed. The third and 
fourth fpinous rays of the dorfal fin with a filament as 
long as the fpine itfelf. 
81. Perea trachichthys, the New-Holland perch : ab¬ 
domen cataphrafted with large carinate’fcales ; mouth 
wide, toothlefs, descending. Eight rays (the four lower- 
moft rough on the edges) in the membrane of the gills, 
14 in the dorfal fin, pedtorals 13, ventrals 7, anal 12, cau¬ 
dal 24. This fpecies is added by Dr. Turton as a fepa- 
rate genus, Trachichthys, from the Nat. Mifcel. No. 106. 
PI. 378. The head is rounded in front, and the eyes are 
very large, with a lilvery iris. It inhabits New Holland; 
about five inches long, and two deep ; body coated with 
rough fcales, fo ftrongly and clofely. inferted, that it is 
not poflible to detach one from the reft without bringing 
with it a portion of the lkin. Gill-covers armed on the 
upper part with a ftrong rough fpine, and a fmall one on 
the lower. Scales fringed and covered with fmall fpines, 
thofe on the abdomen projecting into a (hortifh fpine, 
pointing backwards and forming a (harp keel. Tail 
ftrongly forked: edges of all the fins paler; three firft 
rays of all the fins, except the pectorals, ftrong, rough, and 
finely ferrate outwards. 
IV. Opercula aculeated, as well as fealy. Holocentri. 
The Holocentrus [from the Gr. 0A0?, all, and xht(ov, 
a fpine] is a very confiderable genus in Bloch; as, be- 
fides forne newly-difcovered fpecies, he has included in 
it all the perches which have the dorfal fin undivided. 
Thefe laft we have reftored to their proper places in the 
Vol. XIX. No. 1327. 
591 
fecond and third divifions. The genus has been adopted 
by Cepede, and more recently by Dr. Shaw; but the dif¬ 
ference upon which it is founded is fo fmall, that we have 
no hefitation about placing the remaining new fpecies 
here as an appendix to the genus Perea ; for the defig- 
nation holocentrus, or “ all-fpiny,” applies almoft exclu- 
fively to the fpines on the opercula, or gill-covers. See 
vol. xiii. p. 778, 9. The generic characters, as ftated by 
Drs. Bloch and Shaw, are—Habit of the genus Perea ; 
gill-covers fealy, ferrated, and acuminated; fcales, in 
moft fpecies, hard and rough ; one dorfal fin. See Bloch 
vii. 45. Cepede iv. 327. Shaw iv. 553. 
1. Tail divided, either forked or lunated. 
1. Holocentrus fogo, the Welchman: this fpecies is 
diftinguiflied by having eight rays in the ventral fin, one 
fpine at the firft piece of the gill-cover, two at the fe¬ 
cond. It has 8 rays in tire membrane of the gills, 17 in 
the pefloral fins, i in the ventral, T \ in the anal, 29 in 
the tail, in the dorfal. The body is compreffed, and 
almoft rectangular. It does not go tapering to the tail, 
like moft fi(h : but grows narrower all at once ; and the 
tail preferves the fame thicknefs quite to the fin, which 
is forked. The jaws and palate are rough, like a file, the 
teeth being 'extremely fmall and (harp ; the tongue is 
broad and flippery; the lip-bones of the upper jaw are 
double, and very ftrong. The eyes are large and protru¬ 
ded ; the pupil is black, the iris filvery inclofed in a yel¬ 
low ring. The head is furrowed between the eyes, and 
devoid of fcales. There is one fpine to the front oper¬ 
culum, two to the hinder one ; both are ferrated on the 
edge; and there is a row of tranfverfe fcales on the fore- 
moft one. The gills have a wide aperture. The whole 
body is covered with large, hard, ferrated, fcales, ftrongly 
adhering to the (kin. Two row's of fcales (land up along 
the back, forming a furrow in which the filli can with¬ 
draw the dorfal fin. The fcales cover alfo part of the 
anal fin, which occafions that part to appear as broad as 
the belly. The lateral line is fcarcely vifible. A beau¬ 
tiful red (hines through the (liver colour of the fcales, 
and, being intermixed with ftraw-colour ftripes, forms 
an agreeable diverfity. Its long red fins, and its large 
eyes, give it a beautiful appearance in the water. As the 
bones of the head terminate all in fpines larger or fmaller, 
Artedius has made it a genus of itfelf by the name of 
holocendre, or all-prickly. There are ten (hort fpines at 
the origin of the tail-fin. A round bone is obferved un¬ 
der the peCtorai fin, which is only an apophyfis or pro¬ 
duction of the omoplatus, or bone under the gill-cover, 
which afiifts the aCiion of the peCtorai fin. Another re¬ 
markable thing in this fifii is an aperture which is difeo- 
vered in the upper part of the mouth when the upper jaw 
is brought forward ; to explain this, it muft be remarked, 
that the jaws of fifties are divided in the middle, and 
both movable, whereas in moft other animals the lower 
jaw only is fo ; in the middle, where the two halves of 
the upper jaw meet, each half has a procefs rifing ftraight 
up, which carries the mufclesfor drawing back that jaw ; 
this procefs goes under the (kin betw'een the noftrils ; 
and, when it is drawn back by the protruiion of the jaw, 
the unbroken (kin covers the fpace in other fifties ; but 
in this fpecies the (kin is interrupted, and exhibits an 
aperture. This fpecies is found in all the four quarters 
of the globe. Plumiermadea drawing of it at the An¬ 
tilles ; Brown (aw it at Jamaica ; Duhamel deferibes it as 
belonging to the waters of Europe ; and Bloch received 
it from Africa, where it is called J'ogo. It is the hand- 
fomeft of the genus ; and is much efteemed as food. The 
annexed Plate IV. is defigned to exhibit the fpecies of 
perch called Holocenters ; the prefent beautiful fpecies 
(from Bloch, t. 232.) is (hown at fig. 1. 
( 3 . A variety, which differs in the following particu¬ 
lars. The fpace between the eye and mouth is much nar¬ 
rower, and the fnout is obtufe ; only one fmall fpine 
about the head. The nth fpine of the dorfal fin, inltead 
7 M of 
