ON THE SEA-ANEMONE, SAGARTIA LUCLE. 143 



It is very easy to determine the number of mesenteries on a living individual. 

 Their unions with the outer wall show as longitudinal dark green lines. The number 

 is commonly not symmetrical, a peculiarity common to the genus (Dixon, '88). But 

 in a uniformly twelve-striped individual four such dark lines occur between every 

 two orange stripes (Fig. 1). The orange stripes are represented in the figure by the 

 dark patches in the margin between the primary mesenteries. Thus there are 48 

 mesenteries in a symmetrically twelve-striped form. On section it appears that 

 both the primary mesenteries, that is those that connect with the oesophagus, and 

 the secondary that fall short of it, occur in pairs. In a twelve-striped form these 

 pairs alternate (Fig. 1). The orange stripes occur on the spaces between the primary 

 mesenteries. In such a uniformly arranged individual the new mesenteries arise as 

 in Figure 2 and the orange stripe will appear in the region marked x. But such 

 perfect symmetry does not always occur even in a twelve-striped individual. Figures 

 9, 10, 11, 13, and 14 illustrate some of the more striking asymmetrical arrangements 

 of the orange stripes. The broader bands in these figures represent the older stripes, 

 and the part of the anemone included between them constitutes the old or original 

 part that came to the anemone as the result of division. This part is of a dark olive- 

 green color and the stripes are of a bright orange. Opposed to the old part with the 

 broad orange stripes is the regenerated part, which is of a light, almost transparent 

 green. In this recently regenerated part no stripes may develop for some time as in 

 Figures 12 and 13, or else faint lemon-yellow lines at first appear. These stripes 

 in the regenerated part may appear only long after the primary mesenteries have 

 united with the oesophagus, or they may appear early and even in such numbers as to 

 he between each and every pair of mesenteries (Figs. 9, 11). With age the stripes 

 become broader and of a deeper tint until the characteristic orange color is acquired. 

 By the development of more mesenteries the stripes become pushed apart. Thus 

 there is considerable variation both in regard to the time at which the stripes appear 

 and in regard to the frequency or numbers that are first produced in the regenerated 

 part. The rate and time of development of the stripes seems to be correlated with 

 the rapidity and amount or vigor of regeneration. Along the stripes occur the open- 

 ings for the exit of the acontia, the cinclides. These are in rows of two, three, or even 

 five. In some cases, however, only one cinclis may be present on a single stripe. 

 These stripes then mark the positions of the cinclides. May not their presence per- 

 haps be considered as a case of warning coloration? 



