{286}In _Errina_ the pores are sometimes irregularly scattered, but in _E. glabra_ they are arranged in rows on the sides of the branches, while in _E. ramosa_ the gastropores occur at the angles of the branches only. The dactylopores are situated on nariform projections of the corallum. The ampullae are prominent. There are several gonophores in each ampulla of the male, but only one in each ampulla of the female. This genus is very widely distributed in water from 100 to 500 fathoms in depth. _Phalangopora_ differs from _Errina_ in the absence of a style in the gastropore; Mauritius.—_Pliobothrus_ has also no style in the gastropore, and is found in 100-600 fathoms of water off the American Atlantic shores. _Distichopora_ is an important genus, which is found in nearly all the shallow seas of the tropical and semi-tropical parts of the world, and may even flourish in rock pools between tide marks. It is nearly always brightly coloured—purple, violet, pale brown, or rose red. The colony usually forms a small flabellum, with anastomosing branches, and the pores are arranged in three rows, a middle row of gastropores and two lateral rows of dactylopores on the sides of the branches. There is a long style in each gastropore. The ampullae are numerous and prominent, situated on the anterior and posterior faces of the branches. Each ampulla contains a single gonophore in the female colony and two or three gonophores in the male colony. _Spinipora_ is a rare genus from off the Rio de la Plata in 600 fathoms. The branches are covered with blunt spines. These spines have a short gutter-like groove at the apex, which leads into a dactylopore. The gastropores are provided with a style and are situated between the spines. _Steganopora_[321] from the Djilolo Passage, in about 600 fathoms, is very similar to _Spinipora_ as regards external features, but differs from it in the absence of styles in the gastropores, and in the wide communications between the gastropores and dactylopores. _Stylaster_ is the largest and most widely distributed genus of the family, and exhibits a considerable range of structure in the many species it contains. It is found in all the warmer seas of the world, living between tide marks at a few fathoms, and extending to depths of 600 fathoms. Many specimens, but especially those from very shallow water, are of a beautiful rose {287}or pink colour. The corallum is arborescent and usually flabelliform. The pores are distributed in regular cyclosystems, sometimes on one face of the corallum only, sometimes on the sides of the branches, and sometimes evenly distributed. There are styles in both gastropores and dactylopores.