TUBULARIA. 67 



The preceding observations prove : — 1. The same twig bore at 

 least six successive hydrse. 2. The subsistence of the hydra was from 6 

 to 10 days. 3. The interval required for reproduction required from 

 16 days to 60. These irregularities are extraordinary. 



The ascent of the bud is gradual ; and it is visible within the tube 

 for two or three days before its evolution. 



Thus certain analogies are found between this product and the two 

 preceding in the structure of the inorganic parts, and in the regeneration 

 of successive hydra% from the same portion of the same specimen; nor 

 are the predominant irregularities in less correspondence. 



Propafjation. — Regarding the propagation of the zoophyte, which 

 must certainly influence its position in the Systema, many years elapsed 

 before my observations established the peculiar mode whereby it is ef- 

 fected. 



A splendid group of above fifteen specimens occurred on a live mussel 

 shell. One of these, not 18 lines high, bore 83 hydrse ; and another some- 

 what taller above 100. At least a thousand animated beings decorated 

 the group — a wonderful assemblage of variety and beauty on such a scale. 

 Numerous clusters like yellow ova were interspersed among the hydrae, 

 not within the circuit of the ten taenia, as with the Tubularine of the pre- 

 ceding chapter, but generally around the exterior of the under surface or 

 base of the disc, though disjoined from it ; and sometimes as if compres- 

 sing the hydrse by their number and position. But they were neither 

 confined to any particular place, nor peculiar to the finest of the specimens. 

 Subjected to the microscope, these substances proved of a smooth uniform 

 surface, exactly resembling a minute ovoidal plum, attached by a short 

 pedicle to some part of the stem, but never within the hydra. All in one 

 specimen were ovoidal, those of another irregular, spherical, or ovoidal. 

 They were single, in pairs, or in clusters of seven or eight together. — 

 PI. VIII. figs. 5, 6. 



The whole were preserved most carefully for a long time, but I was 

 disappointed of ascertaining their nature, nor was I more successful in re- 

 spect to some other specimens of the same product. 



Eleven years afterwards, however, several specimens having occurred, 

 VOL. I. ^ 



