[IV ZOANTHARIA ACTINIARIA 38 1 



placed in a separate family, but is in many respects intermediate 

 in character between the Halcampidae and the Actiniidae. 



Fam. 2. Actiniidae. This family contains some of the 

 commonest British Sea-anemones. There is a large flat pedal 

 disc by which the body is attached to stones and rocks. The 

 body-wall is usually smooth, and not perforated by cinclides. 

 The edge of the disc is usually provided with coloured marginal 

 tubercles. There are no acontia. 



Actinia. This genus contains the widely distributed and very 

 variable species Actinia mesemhryanthemum, one of the commonest 

 of the Sea-anemones found in rock pools on the British coast. 

 The colours of this species are often very beautiful (see p. 379) 

 but variable. 



Anemonia is a genus with remarkably long tentacles which are 

 not completely retractile. A. sulcata (sometimes called Anthea 

 cereus) is very common in the rock pools of our southern coasts. 



Bolocera tuediae is, next to Actinoloba dianthus, the largest of 

 the British Anemones. It has very much the same colour as the 

 common varieties of Actinia mesemhryanthemum, but the body- 

 wall is studded with minute, rounded warts. It is found between 

 tide marks in the Clyde sea-area, but usually occurs in deeper 

 water. ' 



Fam. 3. Sagartiidae. This family includes several genera 

 with a contractile pedal disc, with the body- wall usually perforated 

 by cinclides, and provided with acontia. 



The genera may be arranged in several sub-families dis- 

 tinguished by well-marked characters. Among the well-known 

 Sea-anemones included in the family may be mentioned : 



Sagartia troglodytes, a very common British species found in 

 hollows in rocks. It is usually of an olive green or olive brown 

 colour, and the upper third or two-thirds of the body-wall is 

 beset with numerous pale suckers. Adamsia palliata has a 

 white body- wall spotted with bright red patches, and is associated 

 with the hermit crab Eupagurus prideauxii. 



Actinoloba (frequently called Metridium) dianthus is con- 

 sidered the handsomest of all the British Sea-anemones. It has 

 a lobed disc frilled with numerous small tentacles, and is uni- 

 formly coloured, creamy-white, yellow, pale pink, or olive brown. 

 It lives well in captivity, and sometimes reaches a length of 6 

 inches with a diameter of 3 inches (Fig. 164). 



