Types, almost exclusively limited to it, and not found in the Indo-Pacific, are few in number, as _Centropristis_, _Rhypticus_, _Hæmulon_, _Malthe_. A few others preponderate with regard to the number of species, as _Plectropoma_, _Sargus_, _Trachynotus_, _Batrachidæ_, and _Gobiesocidæ_. The Sciænoids are equally represented in both oceans. All the remainder are found in both; but in the minority in the Atlantic, where they are sometimes represented by one or two species only (for instance, _Lethrinus_). B. _Shore Fishes of the Tropical Indo-Pacific Ocean._ The ichthyological boundaries of this part of the tropical zone may be approximately given as 30° of lat. N. and S.; on the Australian coasts it should probably be placed still farther south, viz., to 34°; it includes, as mentioned above, the Sandwich Islands, and all the islands of the South Sea, but not the American coasts. Some eighty genera of Shore fishes are peculiar to the Indo-Pacific, but the majority consists of one or a few species only; comparatively few have a plurality of species, as _Diagramma_, _Lethrinus_, _Equula_, _Teuthis_, _Amphiprion_, _Dascyllus_, _Choerops_, _Chilinus_, _Anampses_, _Stethojulis_, _Coris_, _Coilia_. The Sea-perches, large and small, which feed on Crustaceans and other small fishes, and the coral-feeding Pharyngognaths are the types which show the greatest generic and specific variety in the Indo-Pacific. Then follow the _Squamipinnes_ and _Murænidæ_, the _Clupeidæ_ and _Carangidæ_ families in which the variety is more that of species than of genus. The _Scorpænidæ_, _Pleuronectidæ_, _Acronuridæ_, _Sciænidæ_, _Syngnathidæ_, and _Teuthyes_, are those which contribute the next largest contingents. Of shore-loving Chondropterygians the _Scylliidæ_ and _Trygonidæ_ only are represented in moderate numbers, though they are more numerous in this ocean than in any other. C. _Shore Fishes of the Pacific Coasts of Tropical America_. As boundaries within which this fauna is comprised, may be indicated 30° lat. N. and S., as in the Indo-Pacific. Its distinction from the Indo-Pacific lies in the almost entire absence of coral-feeding fishes. There are scarcely any Squamipinnes, Pharyngognaths or Acronuridæ, and the Teuthyes are entirely absent. The genera that remain are such as are found in the tropical zone generally, but the species are entirely different from those of the Indo-Pacific. They are mixed with a sprinkling of peculiar genera, consisting of one or two species, like _Discopyge_, _Hoplopagrus_, _Doydixodon_, but they are too few in number to give a strikingly peculiar character to this fauna. The Three districts are distinguishable:--