GOBIES AND MUD-SKIPPERS. 
3 8 9 
geographical distribution as extensive as that of the family, but especially well 
represented in tropical and subtropical seas, no less than forty different kinds 
being recorded from those of India alone. These fishes have the body generally 
scaled; two dorsal fins, of which the first is usually furnished with six flexible 
spines; the pelvic fins united to form a disc, which, however, is at most only 
partially adherent to the abdomen; the teeth in more than a single row : and 
the vertical gill-opening of moderate width. The form of the body is subject to 
considerable specific variation; and in some forms the head, and in others a part 
or even the whole of the body is devoid of scales. In some cases there may be 
barbels or warts on the head, and in others a crest on the occiput. There are 
likewise considerable differences in the dentition, some species having large tusks 
among the ordinary teeth. The gobies, of which there are several British marine 
species, are especially partial to rocky coasts, where they protect themselves 
against waves and storms by adhering to rocks by means of the sucker formed 
by their modified pelvic fins ; many of them being often found in the swirl of the 
retreating waves. Some, however, prefer brackish estuaries or lagoons, while 
others again, like the Russian species (G. fiuviatilis) represented in our illustration, 
are exclusively fresh-water. In many of them the male constructs a nest in which 
the spawn is hatched. In the case of the spotted goby, or polewig (G. minutus) 
—a species found for some distance up the Thames—the male, when in tidal 
pools, generally chooses one of the shells of a cockle or some other bivalve for its 
nest; the shell being placed on the sand with its concave surface downwards, 
beneath which the sand is hollowed out and cemented by a special mucilaginous 
secretion from the skin of the fish; a cylindrical tunnel giving access to the nest, 
and the whole structure being covered over with loose sand. The female having 
deposited her eggs, which are fixed to the shell, in this nest, the male mounts 
guard over them, maintaining his watch during the whole period of incubation, 
which lasts from six to nine days. A European goby ( Latrunculus pellucidus), 
belonging to a distinct genus, and characterised by its translucent body, is 
almost peculiar among vertebrates in that its span of life is of only a year’s 
duration. In June and July the spawn is deposited, the eggs are hatched in 
August, while in the late autumn or winter the fishes become fully mature; these, 
however, die off in the following July or August, so that in September only the 
fry are to be met with. 
Omitting all mention of a number of more or less nearly allied 
Mud Skippers. g enera , our nex q representatives of the family are the mud-skippers 
(. Periophthalmus ), remarkable not only for the peculiar physiognomy given them 
by their conspicuous eyes, but likewise on account of their strange habits. These 
fishes, which frequent the coasts and estuaries bordering the Indo-Pacific Ocean, 
and likewise reappear on the shores of West Africa, take their name from their 
prominent eyes, which are set close together somewhat below the line of the 
profile, and are not only capable of protrusion and retraction but are furnished 
with a well-developed outer eyelid. The elongate body is covered with cycloid 
or slightly pectinated scales, extending on to the bases of the pectoral fins; the 
cleft of the mouth is nearly horizontal, with the upper jaw projecting somewhat 
beyond the lower, and the conical teeth are vertical. The first dorsal fin includes 
