METAZOA COELENTERA. 129 



arrangement. Thus the base of the anemone (PI. 198, 

 fig. 3) exhibits a small number of biradial partitions. 



Young and adult stages of the anemone are seen in the 

 alcoholic specimens (No. 199). The cylindrical body is 

 usually attached by its base (No. 199), although it has the 

 power of gliding over surfaces. The mouth is surrounded 

 by tentacles (Nos. 199, 200) which can be drawn in and 

 entirely concealed. The mouth is open and more or less 

 circular in the alcoholic specimens (Nos. 199, 200), but 

 in life it is slit- like. It is provided with two siphono- 

 glyphs. In the living animal these are seen to be lined 

 with long cilia. When the mouth is closed the central 

 parts come together, while the siphonoglyph at either end 

 is open so that a current of water can be kept circulating 

 through the body. The mouth of the adult opens into 

 the flattened internal bag, and the latter into the body 

 cavity, which is divided into chambers by biradial mesen- 

 teries, seen in the preparation (No. 201). At each end of 

 the flattened bag there is a pair of mesenteries called 

 " directives." Four other pairs of long walls reach the 

 central bag, making six pairs of primary mesenteries. 

 Besides these there are cycles of shorter pairs, the num- 

 ber depending upon the age of the anemone. When 

 mature the mesenteries bear the long convoluted repro- 

 ductive organs. 



The mesenteries are not arranged symmetrically and 

 equally distant from one another, as might be inferred 

 from figures often given in textbooks. In a collection of 

 twenty-one anemones sent from Beverly bridge, not one 

 showed a perfectly symmetrical arrangement. In nearly 

 all, six or eight of the mesenteries which reached the 

 central bag were bunched closely together, while the re- 

 maining ones were separated from these by a greater or 

 less distance. One specimen had four biradial pairs and 

 an odd one ; two specimens had six pairs and an odd one ; 

 another was found with seven pairs and an odd one, 

 while still another had eight pairs. 



