376 



COELENTERATA ANTHOZOA 



and these usually support such large and powerful muscle-bands 

 that they appear to be the only mesenteries present. A careful 

 examination of transverse sections, however, reveals the fact that 

 other mesenteries are present. The fifth and sixth pairs of 

 protocnemes seem to be invariably represented, and two or three 

 pairs of metacnemes can also be traced in some species. 



The tentacles are variable in number. In Udvjardsia beau- 

 tempsii, for example, they may be 14-16 in number, arranged in 



a single row round the 

 oral disc. In E. timida 

 they vary from 20 to 24. 

 The normal number ap- 

 pears to be eight tentacles 

 of the first cycle, corre- 

 sponding to the eight 

 primary inter-mesenteric 

 chambers, ;plus 6 or 12 

 tentacles, corresponding 

 with the chambers limited 

 by the more rudimentary 

 mesenteries, — making a 

 total of 14 or 20 ten- 

 tacles ; but by the sup- 

 pression of the two 

 primary dorso - lateral 

 tentacles, or by the addi- 

 tion of tentacles of 

 another cycle, the actual 

 number is found to vary 

 considerably. The 



Edwardsiidea are not 

 fixed to the bottom, but are usually found deeply embedded in 

 sand, the aboral extremity being pointed and used for burrowing 

 purposes. The general colour of the body is yellow or yellowish 

 brown, but it is partly hidden by a short jacket of mud or 

 sand and mucous secretion. The oral crown frequently shows 

 beautiful colours. De Quatrefages relates that in Udwardsia 

 beautempsii the oral cone is golden yellow, and the tentacles, 

 transparent for the greater part of their extent, terminate in 

 opaque points of a beautiful yellowish red colour. 



Fig. 165. — Edwardsia heautempsU. 

 (After de Quatrefages.) 



Nat. size. 



