344 TROPICAL AND SOUTHERN FISHES 



esteemed for the excellence of their flesh. The members of this particular genus 

 may be recognised by the elongation of the fourth ray of the dorsal fin into the 

 shape of a whip-lash ; one of the most common species being the whip-fish {H. 

 macrolepidotus) of Mauritius and north-western Australia. 



The well-known wrasses form a large family of, for the most 



Wra,sscs * 



part, brilliantly coloured fishes frequenting all tropical and temperate 

 coasts. They take their scientific name of Labridcn from their thick, projecting 

 lips. Ten or more species or races are known from British waters, of which the 

 most abundant are the Ballan wrasse (Labrus maculatus) and the striped wrasse 

 (L. mixtus). In the latter the two sexes are coloured differently, the males being 

 striped with blue, while the females are blotched with black. Among the numerous 



BRISTLE-FISH. 



tropical and southern genera, the coral-wrasses (Platyglossus) are restricted to the 



coral-zone, and, like all fishes with that habitat, are the most gorgeously coloured 



of their family. 



Our next representatives of the spiny-finned group of bony fishes 

 Sword-Fishes. r L J . to . i . . , J 



are the sword-fishes and sail-fishes of the families A vjvmdcu and 



Histioplwridce, which belong to the pelagic mackerel-like section, and are the largest 



members of the entire order. These fierce and predaceous fishes derive their name 



of sword-fish from the long spear-like prolongation of the upper jaw, while the 



sail-fishes, which are similarly armed, take their title from the enormous back-fin, 



which plays the part of a lateen-sail when they are swimming at the surface. The 



ordinary sword-fish (Xiphias gladius) of the Mediterranean and North Atlantic 



alone represents a genus in which the hind, or pelvic, pair of fins is absent ; whereas 



in the sail-fishes, such as Histiophorus gladius of the Indo-Pacific, these fins are 



