242 AMPHITEITE. 



hairs were generated from the anterior part of the sundered portions in 

 sixteen or seventeen days ; and in twenty-four days, a regular plume, 

 composed of sixteen or seventeen unequal branchiae, with very short cilia, 

 was reproduced. This became of nearly corresponding proportion to 

 the subject in thirty-three days, and to what is witnessed in the entire 

 animal, being about a fourth of the whole. Fig. 5. In forty-two days 

 it was perfect, having five rows of spots on the ribs, forming a circle in 

 display. But the same disproportion, as described in the former species, 

 subsisted between the plume and the body, and was very conspicuous, 

 for, as the one advanced the other declined. In sixty- three days it was 

 almost half the length of the body. Meantime, the original mutilated 

 animal still survived, bearing its own original plume, while that of the 

 fragment subsisted in vigour, as in the former observation. Figs. 6, 7. 



In another experiment, the body of an entire and vigorous animal, 

 extending an inch, was mutilated of a portion equalling two lines, from 

 the posterior extremity : then of a portion above it equalling four lines. 

 Thus, there were three parts, first, the original, comprehending the plume 

 and antennulse, a. Secondly, the middle portion, b. Thirdly, the pos- 

 terior extremity, c. All were set apart. 



In three weeks, the original anterior, a, with the plume and anten- 

 nulae, remained sufficiently vigorous. Plate XXXII. fig. 8. The middle 

 section, b, had generated a new plume, rising an eighth of an inch. 

 Fig. 9. But no sensible reproduction issued from the upper part of c, 

 the posterior extremity. Fig. 10. The wound having healed, however, 

 without decay or injury, still encouraged expectation of the defective 

 organs. 



Accordingly, in ten days longer, a plume, composed of greenish ribs 

 alone, could be discerned through the sheath, arising from the fragment. 

 This advanced regularly and rapidly : and, in fifty-five days after the 

 section, it consisted of eight perfect branchiae, extending nearly two lines, 

 besides two large and conspicuous antennulse. Fig. 11. ; the same en- 

 larged, fig. 12. 



Thus, it is proved that the elements of the branchial plume reside 

 in different parts of the body of the Amphitrite bombyw. It is also proved, 



