236 AMPHITRITE. 
Prate XXX. 
Fic. 8. Antennule, natural size. 
4. Regenerating plume from a stump within the tube. Trowels, a, 6, 
clasping the edge of the orifice. Scoop or tongue between them, ec. 
. Young specimen in a perfect tube. Branchiz or funnel, a. 
. Another. 
. Young specimen with seven branchiz. 
. The same, enlarged. 
. Fragment, which separated from the posterior extremity of an adult, 
regenerating a branchial plume, a ; secretory glands, 6. 
10. The same enlarged. 
oot GS 
11. The same, with the plume regenerated slightly, enlarged. 
§ 2. AMPHITRITE BOMBYX.—Plate XXXI. Figs. 1, 2, 3, 4. 5. 
The general structure of this animal resembles that of the preceding 
subject, in a luxuriant plume of branchize crowning a vermicular body, 
and in dwelling in a sheath. 
Its name is derived from the materials whereof the sheath is formed, 
being an animal gluten like silk, without earthy particles incorporated 
during its fabrication. 
The total length of the Amphitrite is about three inches, or little 
more, whereof the plume, composed of towards sixty branchize, consti- 
tutes a third, and the body, equalling two-thirds, consisting of sixty or 
seventy segments, is terminated by two white papille. 
The shoulder enlarges as a marginal white frill, from which the 
plume originates ; and each side of the body is bordered by a row of 
short bristly pencils, with a black speck near the roots. A groove com- 
mences at some distance from the frill towards the belly ; and within the 
frill the neck of the plume, which is white, is encircled by a row of very 
dark lines.—Plate XXXI. figs. 1, 2. 
The branchiz of the plume are disposed in lunate arrangement, like 
those of the Cristatella. They bear a narrow resemblance to feathers, 
each consisting of ribs bordered by a double row of active cilia, alike 
numerous, and longer in proportion than those of the preceding species, 
