2 is 



University of California Publications in Zoology. [Vol. o 



was sec-tinned transversely at x, just below the oral edge of the 

 perisare. In forty-eight hours, the stem of the distal portion had 

 increased in length and was anchored by a terminal frustule (fig. 

 15, d). The proximal portion was club-shaped, with hydranth 

 cavity in the thickened oral region (fig. 15, p). Hydranth and 



Fig. 15. — Larva, sectioned at x, with the condition of distal (d) and 

 proximal (p) segments forty-eight hours later. 



Fig. 16. — Regenerating larva, in two states of contraction, from proximal 

 segment of stem after section just distal to edge of perisare. 



stem regions were proportioned as in the normal larva of about 

 thirty hours, and the details of the development were the same 

 for two days, when it died, after three distal tentacles had 

 appeared. The stem had transformed directly into a larva, with 

 the minimum of histological change. Similar transformations of 

 pieces of adult stems will be considered in a later paper. 



Fig. 16 represents in two stages of contraction, the proximal 

 individual regenerating from the stem of a larva with six proxi- 

 mal and four distal tentacles, after section just distal to the oral 

 edge of the perisare. Here the direct transformation of the distal 

 end into the hydranth has involved both naked and covered por- 

 tions of the original stem, differing slightly in the character of 

 their cells, especially in the ectoderm at the line of transition. 



