24 ZOOPHYTES. 



into three limbs, all in flourish. The head of the main portion, evidently 

 the fourth in succession, had 25 tentacula, that of the lowest 22, and the 

 intermediate head, borne on the shortest stalk, interposed between them, 

 had 18. These heads, being deciduous, and new heads replacing them, 

 proved the participation of the whole specimen in the identical nature of 

 the Tubularia.— PI. IV. fig. 26. 



In such cases, the observer must beware of assuming a nascent Tubu- 

 laria, which evolved from an ovum falling on some neighbouring stalk of 

 a group, and affixing itself there, thus presents apparent monstrosity. 

 Here, however, a generating root would betray the truth. 



A luxuriant head having fallen from a specimen, the stem, previously 

 detached from its original site, was now portioned into three sections, the 

 lowest two inches long, each of those above it one. When entire, the 

 higher was thrice the diameter of the lower extremity, for it will be 

 recollected that the stem is smallest at the root. Nothing resulted 

 from the highest section, where it might have been most expected, 

 although it was not in decay, and five months afterwards contained 

 fluid matter, originally the pith. But in ten days a head burst from the 

 lowest section, where it might have been least expected ; and in fourteen 

 one from the top of the middle section. Both were flourishing sixteen 

 days from the date of the experiment, and so continued during a fortnight, 

 meantime generating as usual a light carnation striated neck, half an inch 

 long. Thus was superabundant organization obtained, because two heads 

 cannot naturally subsist at once on the same stalk, nor in the same per- 

 pendicular line. The lower extremity of these sections adhered to the 

 side of the vessel, which rarely happens, and both ascended in diagonal 

 elongation during absence of the heads. Some expectations were indulged 

 of a head germinating from the lower extremities reddening and becom- 

 ing very obtuse, which would have been opposite its natural place. But 

 nothing followed. We shall afterwards find examples of such a generation 

 among the hydraoid zoophytes. 



The preceding experiment proved that the evolution of an elemen- 

 tary hydra — a germ or embryo two inches down the stalk was promoted 

 by an artificial section. 



