vil SCALES IgI 
the result of the curious modifications which their scales 
undergo. - In some of | 
the Coffer-Fishes (Os- 
traction) these — struc- 
tures assume the form 
of polygonal bony 
plates which suturally 
articulate with one 
another and_ enclose 
the trunk in a rigid 
cuirass, from which the 
sealeless tail protrudes 
behind (Fig. 438); Zz 
while in some Globe- Fie. 108.—A, Scale of Antennarius hispidus, x 100; B, 
Fishes and Porcupine- or of a young Malthe vespertilio, x 100. (After 
ertwig.) 
Fishes (e.g. Zetrodon, © ; 
Diodon) the prolongation of the scales into strong erectile spines 
equally well serves the pur- 
pose of protection (Fig. 439). 
Most Teleostomi have 
the scales along the “ lateral 
line ” perforated by single or 
multiple apertures, through 
which the sensory canal 
communicates with the 
exterior. 
In a few Teleosts scales 
are entirely absent, as in 
most Siluridae; or they 
y exist only as microscopic 
vestiges hidden in the skin, 
as in Eels; or, as in such 
naked forms as Antennarius 
marmoratus and Lepado- 
gaster, and in some Silu- 
Fic. 109.—A, Scale of Bualistes capriscus, x20; Yidae, they become reduced 
La Monacanthus scopas, x20. (After to mere papillae of the 
dermis. 
The concentric rings observable (Fig. 105) on the surface 
of many Teleostean scales are.an index to the age of the 
