With regard to variety of forms, as well as to number of individuals, this zone far surpasses either of the temperate zones; in this respect, the life in the sea is as that on the land. Coast fishes are not confined to the actual coast-line, but abound on the coral reefs, with which some parts of the Atlantic and Pacific are studded, and many of which are submerged below the water. The abundance of animal and vegetable life which flourishes on them renders them the favourite pasture-grounds for the endless variety of coral-fishes (_Squamipinnes_, _Acronuridæ_, _Pomacentridæ_, _Julidæ_, _Plectognathi_, etc.), and for the larger predatory kinds. The colours and grotesque forms of the Fishes of the Tropics have justly excited the admiration of the earliest observers. Scarlet, black, blue, pink, red, yellow, etc., are arranged in patterns of the most bizarre fashion, mingling in spots, lines, bands; and reminding us of the words of Captain Cook when describing the coral-reefs of Palmerston Island: “The glowing appearance of the Mollusks was still inferior to that of the multitude of fishes that glided gently along, seemingly with the most perfect security. The colours of the different sorts were the most beautiful that can be imagined--the yellow, blue, red, black, etc., far exceeding anything that art can produce. Their various forms, also, contributed to increase the richness of this sub-marine grotto, which could not be surveyed without a pleasing transport.” Of Chondropterygians the _Scylliidæ_, _Pristis_ (Saw-fishes), _Rhinobatidæ_, and _Trygonidæ_ attain to the greatest development. Of Acanthopterygians _Centropristis_, _Serranus_, _Plectropoma_, _Mesoprion_, _Priacanthus_, _Apogon_, _Pristipoma_, _Hæmulon_, _Diagramma_, _Gerres_, _Scolopsis_, _Synagris_, _Cæsio_, _Mullidæ_, _Lethrinus_, _Squamipinnes_, _Cirrhites_, some genera of _Scorpænidæ_, _Platycephalus_, _Sciænidæ_, _Sphyræna_, _Caranx_ _Equula_, _Callionymus_, _Teuthis_, _Acanthurus_, _Naseus_, are represented by numerous species; and the majority of these genera and families are limited to this zone. Of Pharyngognaths the _Pomacentridæ_, _Julidina_, and _Scarina_, are met with near every coral formation in a living condition. Of Gadoids, a singular minute form, _Bregmaceros_, is almost the only representative, the other forms belonging to deep water, and rarely ascending to the surface. Flat-fishes (_Pleuronectidæ_) are common on sandy coasts, and the majority of the genera are peculiar to the Tropics. Of _Physostomi_ only the _Saurina_, _Clupeidæ_, and _Murænidæ_ are represented, the _Clupeidæ_ being exceedingly numerous in individuals, whilst the _Murænidæ_ live more isolated, but show a still greater variety of species. Lophobranchii and Sclerodermi are generally distributed. Branchiostoma has been found on several coasts.