1 6 THE DEPTHS OF THE SEA. [chap. i. 



the zone of c tangles ' for the first few fathoms, and 

 in deeper water of the beautiful scarlet sea-weeds 

 (floridece). It is always under water except at the 

 very lowest ebb of spring tides, when we get a 

 glimpse of its upper border. The laminarian zone 

 produces abundance of vegetable food, and, like the 

 littoral zone, may be divided into subordinate bands 

 distinguished by differently tinted algae. Animals 

 swarm in this zone, both as to species and indi- 

 viduals, and are usually remarkable for the bright- 

 ness of their colouring. The molluscan genera 

 Trochus, Lacuna, and Lottia are characteristic of this 

 belt in the British seas. 



The Laminarian zone is succeeded by the Coralline 

 zone, which extends to a depth of about fifty fathoms. 

 In this belt vegetation is chiefly represented by coral- 

 like millipores, and plant-like hydroid zoophytes and 

 bryozoa abound. All of the higher orders of marine 

 invertebrates are fully represented, principally by 

 animal feeders. The larger crustaceans and echino- 

 derms are abundant ; and the great fishing-banks 

 frequented by the cod, haddock, halibut, turbot, and 

 sole, belong properly to this zone, although they 

 sometimes extend into water more than fifty fathoms 

 deep. Characteristic molluscan genera are Buccinum, 

 Fusus, Ostrea, and Pecten; and among echinoderms 

 in the European seas we find Antedon sarsii and 

 celiicus, Aster acanthion glaelale and rtibens, Ophio- 

 tlirix fragilis, and on sand, Ophioglypha lacertosa 

 and albida. 



The last belt defined by Eorbes as extending from 

 about fifty fathoms to an unknown lower limit is the 

 zone of deep-sea corals. " In its depths the number 



