16 ZOOPHYTES. 



wards. If, in this first instance, the stem descends from the elements of 

 the disc, or perhaps, in more correctness, from the vicinity of the stomach, 

 it is probably from the elements of the like originating parts in all sub- 

 sequent regenerations. This, indeed, is not to be readily understood or 

 explained, for we always presume the disc as at the highest point, where it 

 actually appears as sustained on the regenerated neck. But we must con- 

 ceive what is the earlier stage ; and it will be allowed that the process is 

 advancing within the tubular stem. The rudiments of the essential organs 

 are in preparation to unfold before the regenerated mass has rose so high 

 as to present itself to view. Thence it may be concluded that the whole 

 evolution is developed from the head as reproductions from the simple 

 hydra or polypus. This would sanction the presumption that the elemen- 

 tary organization of all the subsidiary parts resides in what we denominate 

 the head of the tubularia. 



Overpassing the point, however, for the present, we shall .devote a para- 

 graph to the occurrence, the frequency, the intervals, and the concomi- 

 tants of so wonderful a property as the renewal of defective parts, one 

 which seems to retard the stroke of death, and almost to defy mortality. 



But the finest, most luxuriant, picturesque, and interesting specimens 

 are less adapted for protracted observation than those which are meagre 

 and solitary ; for the latter are neither so ready to spread corruption from . 

 their exuberance, nor do destructive parasites find a hidden asylum there. 

 A group of thirteen obtained on March 29, had had three vacant 

 stalks ; the rest bore heads in various stages. — (PI. II. fig. 1, half size.) 

 All had fallen on the 31st ; but the ruddy tinge of the three vacant stalks 

 now announcing speedy reproduction, a head with 22 tentacula issued from 

 one of them, on the 6th of April, though to enjoy only short existence, as 

 it fell on the 9th, It was replaced on the 21st, by one with 18 tentacula, 

 which fell on the 26th. (Fig. 1, g.) The head b, originally with 20 tenta- 

 cula, flourished April 9, and decaying on the 15th, wasrejjlaced by another 

 with 20 tentacula also, which fell on the 30th. The heads c and d flou- 

 rished April 10. The former, on its fall, was replaced on May 4 by a new 

 head, which fell on the 9th. On the 7th of April e flourished, and it de- 

 cayed on the 11th. On the 5th, the head/ flourished, and it still subsisted 



