532 Miscellanea Zoologica. 
never observed the worm naturally to evolve a proboscis, though . 
every pains may be taken to force it to do so, by irritations, by keep- 
ing it in sea water until it corrupts, by immersion in fresh water, 
or in spirits.* 
The intestine lies loose in a distinct abdominal cavity (PI. XVII. 
Fig. 5, and PI. XVIII. Fig. 1,) or canal excavated through the cen- 
tre of the body. This canal seems to contain besides a grumous fluid, 
which may frequently be observed moving rapidly up and down in 
irregular currents dependent on the contractions of the worm or in- 
testine, and not at all analogous to the currents within the tubes of 
zoophytes. It is fringed along each side with a close series of vesi- 
cles or cells formed, in the true Nemertes, apparently by the folds 
of a membrane, while in the sub-genus Borlasia, they are separate, 
and as it were excavated in the parenchyma of the body, (PI. XVIII.) 
The resemblance between this structure and what have been 
called ccBcal appendages in some allied worms is obvious, t though 
not very exact, for they are not produced from, nor in organic con- 
nection with the alimentary canal, as is manifest from their remain- 
ing unaffected during the motions of the latter, which moreover may 
be removed entirely from the body without bringing with it, or 
tearing away, the presumed coeca. These are always full of some 
opaque matter in the Nemertes, and some observations lead me to 
believe, that it varies in intensity at least according to the nature of 
the animal's food, whence I conclude they belong chiefly to the di- 
gestive system ; while the ova appear to be developed in their in- 
terstices, and in the space between them and the skin, (PI. XVII. Fig. 
2.) But in Borlasia the coeca are more distinctly vesicular and iso- 
lated, and although the depth of colour of their contents varies also, 
yet they are usually clearer and paler than the surrounding paren- 
chyma, or as it were empty, and 1 have plainly seen in them, not 
often, indeed, oviform bodies, which again have not been detected in 
the interstices, (PI. XVIII. Fig. 3.) We seem, then, to have com* 
bined in them a duplicity of function, they are both nutrient and 
* In some cognate species, Otho Fabricius observed the intestine tp be ex- 
truded when no compression was used, but still under circumstances easily re- 
concileable with our explanation. " De orificio antico infero tubulum pallidum 
in agone mortis exserit :" i. e. Planaria rubra, Faun. Grcenl. p. 324; also p. 325. 
| Compare our figures of this structure with that of the Diplozoon para- 
doxum of Nordmann in Ann. des Sciences Nat. V. xxx. p. 382, pi. 20. This 
figure, on a reduced scale, is copied into the Cyclop, of Anat. and Physiology, 
i. p. 654, fig. 328 ; and into Kirby's Bridge water Treatise, pi. 1. B. fig. 4. 
The comparison may be usefully extended to the Annelides, Cyclop, of Anat. 
and Phy. i. p. 169, fig. 70 ; Roget, Bridgew. Treat, ii. p. 103, fig. 260; and to 
the Tania, Ibid. ii. p. 83, fig. 247. 
3 
