200 TEREBELLA. 
tion between them, both in habits and configuration, be obvious, few 
have attempted to correct the error. 
The largest specimens of the Shell-binder extend above five inches. 
Pencils of several bristles and fleshy stumps down the sides, long flexible 
tentacula, a mouth with active lips, resemble those of the others. The 
posterior extremity is slightly trumpet-shaped.—Plate XXVIII. fig. 4. 
The branchiz consists of two bunches of ten or twelve beautiful 
florid fleshy filaments in each, which resemble expanding ringlets, spirals, 
or screws. Their incessant motion by contraction and dilatation, together 
with the involution of the parts, renders it impracticable to discover du- 
ring life, whether these bunches are collectively sustained each on a short 
stem, both on one stem, or whether they originate from the skin. They 
are confused, decayed, and disfigured in death. A very vivid crimson 
spot marks the extremities, fig. 5. The body of the animal is also of a fine 
red, probably speckled, because specks are exposed by fading of the deeper 
hue, especially towards the lower extremity. About twenty-five tenta- 
cula, infinitely stronger, and considerably longer than those of the Tere- 
bella litteralis, form the complement belonging to the present species ; 
they are at least five times their diameter. They are nearly the length 
of the body, and capable of laborious efforts. Flattening like a ribband, 
they fold longitudinally in seizing an object. 
The fashion of the operation of the tentacula is according to the 
service required. The portion applied to the smooth surfaces is flatten- 
ed ; or the longitudinal fold, naturally preserved by the whole tenta- 
culum, opens to seize and convey solid substances to whatever point is 
required, fig. 6. Each portion of the tentaculum is endowed with a 
prehensile faculty independently of every other portion, so that, if the 
middle applies to any surface, or seizes any object, the remainder, both 
behind and before, can fulfil similar functions at the same moment. <A 
number thus affixed by intermediate points in their length, resemble so 
much extended cordages. A row of round red spots runs down the 
middle of each, fig. 7. 
A strong musky odour exhales from some specimens of the Tere- 
bella conchilega recovered from the deep sea. 
