ASEXUAL REPRODUCTION IN SAGARTIA 



235 



TABLE 4 



In this table are shown the mesenteric formulas of two additional natural pairs. 

 iVo. 15 showed some evidence of a preceding regeneration, hut the limits of the 

 regenerated region were not clear. 



This table presents the mesenteric formulas of six groups of polyps, each group 

 derived from a single individual by natural fission. The number of zones of 

 regeneration indicates that the multiple divisions involved are successive rather 

 than simultaneous. 



Certain regenerated polyps show two new areas. In these cases only hounding mesen- 

 teries are represented in the old region on the same horizontal line with the new 

 mesenteri^.s. Two such specimens (nos. 17, 19) have a pair of complete mesen- 

 teries in the old region between the two division planes. This pair is represented 

 in the table in a horizontal space interposed between the lines showing the hound- 

 ing mesenteries. To arrive at the complete formula of a polyp with two regener- 

 ating regions, the symbols of the first new area must he read, in reverse order, 

 between the extremes of the old area represented on the same line. Similarly, 

 the second new area must he inserted in -reverse order between the limits of the old 

 region shown on the same line with it. This may be most conveniently illustrated 

 by no. 19b, of which a section is represented in figure 32. No. 19a is repre- 

 sented in figure 27, no. 19d in figure 30. The mesenteric formulas (disregarding 

 incomplete mesenteries and distinctions between old and new mesenteries) of this 

 and the other available fully regenerated products of division of no. 19 may he 

 represented as follows : 



No. 19a dd, cc, cc, dd, cc, cc (fig. 27). 



No. 19b dd, cc, cc, cc, cc, cc, dd, cc, cc, cc, cc (fig. 32). 



No. 19d dd, cc, cc, dd, cc, cc (fig. 30). 



No. 19 ivas described before division as having two ivhite bars on the oral disc and 

 twelve orange stripes. Its formula was probably, like that of the specimens shown 

 in figure 25, as follows : dd, cc, cc, dd, cc. cc. The lost part was very probably 

 like No. 19c in having no old siphonoglyph or cVrectives. No. 20 was triglyphic 

 before fission, as determined by the ivhite bars. The lost part must have possessed 

 two old siphonoglyphs and pairs of directives. 



Daggers (t) serve to call attention to boundaries in tivo cases, Nos. 18b and 22b, 

 where apparently a second plane of fission passed in the plane of junction of old 

 tissue with new tissue regenerating after a shortly preceding divison. For dis- 

 cussion see page 188. 



