5°° 



CCELENTERA TES. 



small polyp, which settles down and commences to secrete its pedestal and then to 

 bud, thus starting a new coral-stock. 



Six-Rayed Polyps, — Order Hexactinia. 



This name must not be taken too strictly. It is true that it was applied in 

 good faith, because it was believed that this order always had exactly six or 

 some multiple of six as the number of the tentacles ; but corals are tied by no 

 such rigid rules, and all we can say is, that the number of tentacles in this 

 order generally approximates to some multiple of six. Among the Hexactinia 

 the sea - anemones take the first place. They spread over all seas, being 

 especially plentiful in the temperate zones, near the coast, at depths which 

 bring them within the reach of every observer. They are distinguished by their 

 solitary manner of life, their size, and their vivid and usually beautiful colouring. 

 The skin is firm and leathery, and often covered with warts. It does not secrete 

 any calcareous skeleton either inside or outside, so that the animal is soft and 



capable of great contraction and changes 

 of shape. Most sea-anemones use the 

 basal disc for attachment, and can move 

 from place to place by means of it, but 

 a few species bore into sand with the 

 posterior end of the body, or else secrete 

 or build a sheath which they inhabit. 

 In our coloured Plate are depicted, in 

 their natural brilliant colours, a number 

 of sea -anemones living in the Naples 

 aquarium. To the left, in the fore- 

 ground, are two examples, one extended 

 and the other contracted, of the red 

 Actinia equina, which varies greatly 

 in colour. In the centre of the group, 

 somewhat to the left, there is an ex- 

 tended specimen, and near the right 

 edge a strongly contracted specimen of 

 the lovely green Actinia carl. Other beautiful forms are found in the two 

 striped anemones, Ragactis pulchra and Gereactis aurantiaca. The sun-anemone 

 {Heliactis bellis), again, varies greatly in colour but is always elegant, and the 

 same may be said of the trumpet - anemone with spotted tentacles {A^ptasia 

 mutabilis). In the foreground at the centre a hermit-crab is seen carrying with 

 him his guest, the cloak-anemone ( Adamsia palliata). A less conspicuous anemone 

 (Eloactis mazelii) is provided with somewhat long cylindrical tentacles. The 

 Anemonia sulcata lets its tentacles float gracefully, while the vestlet (Cerianthus 

 nibranaceus), of varying colour, hungrily stretches out its arms in all directions. 

 Gladactis costaz, which is covered with warts, is no less voracious, but with apparent 

 apathy allows its tentacles to droop around it. 



These quiet, externally beautiful, and apparently harmless creatures are in 



larvje of sea-anemone (magnified). 



