
HISTORY AND ANATOMY OF THE GOLDFISH 

fin acting simultaneously while the left remains pressed to the body; if 
the motion is to be checked, the ventral fins are erected and expanded 
vertically ; if the motion is to be retrograde, a backward stroke is made 
with all the paired fins and the dorsal and anal fins held rigidly upright, 
the caudal fin being either held on a line with the body or slightly relaxed; 
and should the retrograde movement be in either direction, the caudal fin 
is flexed to the opposite side. 
By observing injured fishes the purpose of the fins will be manifested. 
If a pectoral fin is useless or both a pectoral and a ventral fin on the same 
side, loss of balance will ensue, the fish falling on the opposite side ; with- 
out both the pectorals, the head sinks ; without the ventrals, the motion 
is unsteady; without the dorsal and anal fins the motion is zigzag; with- 
out the caudal fin, forward movement is labored and slow; and without 
any of the horizontal and vertical fins, the fish floats helplessly on its back, 
this being the heaviest part of the body. 
The head and fins of the goldfish are naked, that is, devoid of scales; 
but the body is covered with an even layer of cycloidal scales which con- 
sist of thin, flexible, horny discs, almost circular in form and evenly imbri- 
cated, or overlapping each other like tiles, with the posterior parts extend- 
ed and free, the anterior parts being embedded 
imeeiescepidermis and muscular tissue. Mig.’ 3: 
They have an enameled surface, showing a fine 
striation concentric to the margin with stiffening 
ribs radiating from the rear. Their arrangement 
is in an oblique transverse section across the body. 
On each side, reaching from the head to the caudal 
fin, there is a row of scales different from these in 
structure, which constitute the /atera/ line. Each 
of these scales is perforated by a tube leading to a 
duct connected with a sac in the head; their func- 
FIG. 3—Greatly enlarged scale 
tion being the excretion of mucus which covers the of the Goldfish and diagram 
body to lessen the friction of scales and water, and 

of imbrication. 
to make it impervious thereto. This mucilaginous system is also pro- 
vided with nerves and is the seat of a peculiar sense which corresponds to 
the organs of touch and hearing. 
The digestive system of the goldfish is simple and adapted to its 
natural mixed diet. Fig. 4. Devoid of teeth, a limited mastication only 
takes place in the throat, which, for this purpose, is provided with a num- 
ber of bony protuberances. The mouth is formed of the maxillary and 
the mandible bones, having labial folds or lips. The cesophagus is 
