SEXUAL SELECTION: see SELECTION : Sexual Selection. SEYCHELLES (sa-shel), an archipelago in the Indian ocean, islands and islets—situated between 3° 38' and 5° 45' S., and 52° 55' and 53° 5o' E. Together with the Amirantes, Cos moledo, Aldabra and other islands they form the British colony of Seychelles. The outlying islands lie south-west of the Seychelles group and between that archipelago and Madagascar. The islands under the Seychelles government have a total area of 156 sq.m. There are in addition 40,000 to so,000 sq.m. of coral banks within the bounds of the colony.
The Seychelles lie, with two exceptions, towards the centre of a large submarine bank and are all within the 5o fathoms line.
Mahe, the largest and most central island, is 600 m. north-east of the northernmost point of Madagascar. The other chief islands form two principal groups : (i.) Praslin, with La Digue, Felicite, East Silver, West Silver, Curieuse and Aride; (ii.) Silhouette, and North Island. The most easterly island is Frigate, the most southerly Platte; on the northern edge of the reef are Bird and Denis islands.
Mahe is I 7 m. long, and from 4 to 7 broad and of highly irregu lar shape. There are small areas of lowlands, chiefly at the mouths of the rivers but most of the island is mountainous, and in general the hills rise abruptly from the sea. The highest peaks are Morne Seychellois, 2,993 ft., and Trois Freres, 2,390 ft. The main ridge runs north and south and from the heights descend many torrents, the whole island being well watered. The principal harbour, Port Victoria, is on the north-east coast and is approached by a deep channel through the coral reef which fringes the entire eastern side of the island. Of the small islands close to Mahe the chief are St. Anne and Cerf, off the east, and Conception and Therese off the west coast.
Praslin island is 8 m. long and from 1 to 3 m. broad and its highest point is 1,260 ft.; La Digue covers 4 sq.m., and its greatest height is 1,175 ft.; Silhouette, roughly circular, covers 8 sq.m. and culminates in Mon Plaisir, ft. None of the other islands exceeds 1 sq.m.
of the islands are of granite (hornblende or hornblende-biotite variety) in places fringed by coral reefs ; Sil houette and Long islands are of typical syenite whilst there are dykes and sheets of a younger vogesite, dolerite, porphyrite suite. Bird and Denis islands are of coral limestones while the basement rocks are represented by clay slates on Silhouette island and horn stones on Stag's island. The group is probably a detached and
partially submerged portion of Gondwanaland. Inland cliffs indi cate a recent uplift of about 200 ft.
climate is healthy and equable, and the tem perature varies on the coast from about 68° to 88° F, falling at night in the higher regions to 6o° or 55° F. The mean coast tem perature exceeds 79° F. The south-east monsoon blows from May to October, which is the dry season, and the west-north-west mon soon from December to March. During April and November the winds are variable. The average annual rainfall on the coast is oo•8 in. ; it increases to about 120 in. at a height of 600 ft. and at heights exceeding 2,000 ft. is about 150 in. The Seychelles lie outside the track of the hurricanes which occasionally devastate Reunion and Mauritius. The public health is good.
Flora and Fauna.—Both flora and fauna include species and genera peculiar to the Seychelles. Of these the best known is the Lodoicea sechellarum, a palm tree indigenous only in Praslin island, but since introduced into Curieuse—noted for its fruit, the so-called Maldive double coconut or coco de mer. An other tree found only in the islands is the capucin (Northea sechel larum), now ravaged by an introduced green beetle. Charac teristic of the forests of the coastal belt are the mangrove and Pandanus, and, a little inland, the banyan (Ficus), Pisonia and Hernandia. The coconut is a characteristic feature of the coast. The forests of the granitic land have the characteristics of a tropical moist region, palms, shrubs, climbing and tree ferns grow ing luxuriantly, the trees on the mountain sides, such as the Pan danus sechellarum sending down roots over the rocks and bould ers from 7o to Ioo ft. Of timber trees the bois gayac has disap peared, but bois de fer (Stadtmannia sideroxylon) and bois de natte (Maba sechellarum) still flourish on Silhouette Island. Be sides cutting for building, the jungle was largely cleared for the plantation of vanilla; while a multitude of other tropical plants have been introduced. The most important of the trees intro duced since 190o are various kinds of rubber, including Para (Hevea Brasiliensis), which grows well. For other introduced plants see below, Industries.