140 VARIATION IN THE NUMBER OF STRIPES 



attached to the under side or more frequently to stones that are buried a half-inch 

 or so under the sand. When expanded S. leucolena extends above the surface of 

 the sand, but when disturbed it contracts out of sight into the sand. S. lucise has a 

 shorter column, is of a dark olive-green color, and is marked by a number of bright, 

 parallel, orange- or lemon-colored stripes that extend from the oral opening to the 

 base and mark the position of mesenterial interspaces. S. leucolena is very shy when 

 in its natural surroundings. Thus a shadow caused by the hand or by the flight of 

 a crow is at times sufficient to cause it to retreat into the sand. To stupefying and 

 killing reagents, however, it responds more satisfactorily than S. lucise, which must 

 be killed at the very moment of complete stupefaction in order to be preserved 

 expanded. If allowed to stand in a state of complete stupefaction even for a short 

 time, it begins to regain sensitiveness. A strong solution of magnesium sulphate is 

 the most satisfactory stupefier. If the anemone inclines to contract during stupe- 

 faction it can be induced to expand again by gently swaying the dish back and forth. 

 Both species must be stupefied and killed while attached to some foreign object, as 

 it is impossible to handle them directly without their contracting. Warm corrosive 

 sublimate or picro-sulphuric acid are usually satisfactory killing reagents. Unfor- 

 tunately the orange bands fade out within a half -hour in whatever way the anemone 

 is killed. 



Professor Verrill gives the number of these orange stripes as " 12 (sometimes 24)." 

 The stripes were counted on 751 individuals at Cold Spring Harbor. The number 

 varied from to 20. In plotting these counts the resulting curve is a multimodal 

 one (PI. X, Fig. 15) with five maxima. The highest mode occurs at 12, with secondary 

 maxima at 16, 8, 4, and 1. At first sight such a variation in the number of stripes 

 seems almost meaningless. A clue to the interpretation of this variation was obtained 

 when several pairs of individuals were found in close proximity with a groove or 

 fold on each leading from the oral opening to the base. The stripes on these pairs 

 were arranged in the proportions 9-3, 4-8, 5-7, respectively (Figs. 3, 4, 5). The 

 sums of 9 and 3, of 4 and 8, and of 5 and 7 each make 12, the number of stripes 

 previously observed as the most frequent condition. Other pairs with stripes 

 arranged in the proportions 3-3 (Fig. 6) and 7-1 (Fig. 7) were also observed. 



The question at once followed, are not these pairs derived from a single individual 

 by longitudinal division? The apportionment of the stripes would then depend on 

 the position of the plane of division and upon the amount of regeneration accom- 

 plished before another division occurs. When observed immediately after a division 

 there would be little time for regeneration and hence for the assumption of new 

 stripes. 



