ASEXUAL REPEODUCTION IN SAGARTIA 207 



from having any complete list of the factors concerned, and 

 from understanding fully their order of effectiveness, much less 

 their fundamental nature. 



Pairing of mesenteries 



The tendency to form, ultimately, unilateral pairs of mesen- 

 teries, i.e., pairs whose members lie on the same side of the 

 directive plane, is apparently very strong (except in the case of 

 directives) in the regenerating regions of all these species of 

 anemones. This is especially evident in S. luciae, where it 

 usually involves the matching up of regenerating mesenteries 

 with old ones. There is no evidence, however, that non- 

 directive mesenteries destined to become complete ever arise in 

 regeneration as unilateral pairs. In every case described, one 

 member of the pair precedes in development. According to 

 their manner of development, then, the complete mesenteries are 

 what have been commonly referred to as 'primary' mesenteries. 

 They correspond in order of appearance with the ' Hauptsepten' 

 of the Hertwigs (79, pp. 81, 88), with the ' protocnemes' of 

 Duerden ('02, p. 388), and with both the 'protocnemes' and the 

 'deuterocneme's of McMurrich ('10, p. 4). The first cycle of 

 mesenteries arising as unilateral pairs in the primary exocoels 

 are, then, secondary mesenteries. They are 'metacnemes' 

 according to Duerden 's terminology and ' zygocnemes' in McMur- 

 rich's. As already stated, there is no evidence that the latter 

 ever become complete in the forms whose regeneration has been 

 studied. 



ORANGE STRIPES AND CINCLIDES 



Some observations on the relation of the orange stripes to the 

 processes of fission and regeneration in S. luciae have been made 

 by Davenport ('03, pp. 140, 143). Her statements will be re- 

 ferred to in connection with the evidence I have collected bearing 

 upon the points involved. 



In a well-expanded living animal with brightly colored orange 

 stripes it is not difficult to determine the relative positions of 



