1902.] NATURAL SCIENCES OF PHILADELPHIA. 771 



although somewhat different in shape, as nearly as one could esti- 

 mate its bulk, it corresponded exactly with the bud which had dis- 

 appeared. Similar observations were so numerous that it seems 

 unavoidable to consider the motile form a normal phase in the 

 non-sexual as in the sexual process of multiplication. The precise 

 nature of this intermediate condition is not yet determined. It 

 seems probable that it is a creeping uuciliated form, although my 

 first conjecture, that it was a ciliated planula, has not yet been 

 proven erroneous.^* This peculiar phase is an interesting case of 

 reversion in the nou -sexually developed larva to a condition earlier, 

 in point of ontogenetic order, than that of the parent at the time 

 of budding. 



The subsequent history of the bud has been 'definitely followed. 

 After settling down upon the boltom it repeats the changes which 

 occur in the sexually produced polyp. The newly arisen larva 

 (fig. 9) loses its planula shape, becoming shorter and thicker, espe- 

 cially at the base, on account of the plastic character of the tissues 

 (fig. 10). It has now secured a firm hold upon the bottom, being 

 so closely applied that it is quite hard to dislodge it. The cells 

 at the base increase in thickness until they form a columnar epithe- 

 lium. After the first day a slight pit indicates the point at which 

 the coelenteron is to open externally. This process, as observed in 

 a number of cases, is exactly the same as in the sexually produced 

 polyp. The tentacles also make their appearance in the same 

 manner as described for the hydra which developed from the egg. 



The length of time required for the complete development of a 

 bud, from its first appearance on the hydrocaulus of the parent as 

 a simple knob until the completion of the formation of the coelente- 

 ron and the ^appearance of the tentacles, is from ten to fourteen 

 days: (a) the first period, including as far as the detachment of 

 the bud, 5 days; (6) motile form, 2 to 4 days; (c) from attach- 

 ment to appearance of tentacles, 3 to 5 days. These periods refer, 

 of course, to specimens in captivity. 



PI. XXXII, fig. 17, shows a specimen from an entirely different 

 lot of polyps from those which exhibited the budding phenomena 

 shown in the text figures. This polyp was killed when 23 days old. 

 It may not be a normal individual, but as it shows a tendency to 

 divide transversely it seems worth while to call attention to it. The 



" Perkins, loe. cit. 



