The anus (not seen) is on the sternal surface.
The zooids are a modification of the type of structure known in Balanhglossus, from which they differ principally in the following respects: (i.) The alimentary canal, instead of being straight, has a U-shaped flexure, the dorsal line between the mouth and the anus being short.
It should be to the right of the anus were this the case.
The torsion of the visceral hump is not carried out very fully, the consequence being that the anus has a posterior position a little to the right of the median line above the metapodium, whilst the branchial chamber formed by the overhanging mantle-skirt faces the right side of the body instead of lying well to the front as in Streptoneura and as in Pulmonate Euthyneura.
But in the anthropoid Anus cg va.gina.
The mouth opens at one extremity of the body and the anus at or near the other.
In such cases the blastopore may entirely close, and both mouth and anus develop as new ingrowths (stomodaeum and proctodaeum), whilst, according to the observations of N.
Just in front of the anus there is in Chaetosoma a double, and in Tristicochaeta a triple row of about fifteen stout cylindrical projections upon which the animals creep. The females are a little larger than the males; in Ch.
No shell; limaciform; terrestrial; female aperture on right side in middle of body; anus posterior.
Sub-Class II.-Euthyneura The most important general character of the Euthyneura is the absence of torsion in the visceral commissure, and the more posterior position of the anus and pallial organs.