382 
SPINY-FINNED GROUP. 
preopercular bone is simple, but becomes branched in many of the marine forms. 
The common fresh-water species, which ranges over Central and Northern Europe 
to Northern Asia, seldom exceeds 4 or 5 inches in length, and is more generally 
found in small streams than in large rivers. It has a well-known habit of con¬ 
cealing its broad and flat head beneath loose stones on the river-bottom, and in 
this position will lie motionless for hours, but when disturbed swims swiftly away. 
Its food consists of the larvae of water-insects and crustaceans, as well as the eggs 
and fry of other small fish. The other British representatives of the genus are 
all marine, and include the sea-scorpion ( Cscorpius ) and father-lasher ( C. bubalis), 
both of which are also found on the opposite side of the Atlantic, as well as two 
other less common species. The males of the common marine species are stated 
to build a nest of stones and seaweed for the reception of the spawn; and to guard 
and defend the young fry when hatched. 
On the Indian and Australian coasts the bull-heads are represented by the 
so-called flat-heads, or crocodile-fishes ( Platyceplialus ), in which the much 
depressed head is more or less fully armed with spines, and the body covered 
with ctenoid scales; the anterior spine of the first dorsal fin being isolated from 
the rest, and teeth present on both the vomer and palatine bones. Day writes of 
these fishes that “ the wounds from their spines are dreaded because of the violent 
irritation they occasion. Their eyes are peculiar; the iris possesses two semi¬ 
circular flaps, one above, the other below, the upper being usually the larger; 
these flaps can be brought close together, probably under the stimulus of light.” 
Gurnards Of a decidedly ugly appearance, the gurnards ( Trigla ) are easily 
recognised by their enormous, square, and elevated heads, in which 
the upper surface and sides are entirely bony, and likewise by the finger-like 
first three rays of the pectoral fins, which serve not only for walking on the 
sea-bottom but likewise as organs of touch. There are two dorsal fins, of which the 
spinous is tall, and the soft one long, low, and similar to the anal; the tail-fin 
being slightly rounded. The teeth are villiform; and the air-bladder, which is 
generally furnished with lateral muscles, may be divided into two longitudinal 
halves. They have been divided into three subgenera, of which the typical one 
is characterised by the absence of teeth on the palatines, and the small size of the 
scales, with the exception of the highly modified ones forming the lateral line, 
which are large, triangular, and spiny. The second group is distinguished by the 
medium size of the scales; while in the third teeth are present on the palatine 
bones. Their colours are frequently brilliant, and the fins highly decorated. 
The genus is represented by some forty species, distributed over all temperate and 
tropical seas, out of which no less than seven are found in British waters. Their 
flesh, which is firm and flaky, and of a pale orange-pink tinge, is extensively used 
as food. One of the best known of the British species is the red gurnard (I pini), 
which seldom exceeds 12 or 14 inches in length, and, when freshly caught, is of 
•a bright red colour, with the sides and under-parts silvery white, and the fins 
reddish white. Its food consists of crustaceans, which give the pinkish tinge to 
its flesh, and the spawning-season is May or June. The sapphirine gurnard 
(T. hirundo), which is the one represented in the woodcut, is another British 
.species, taking its Latin name from the length of the pectoral fins, and its English 
