AND HABITS OF THE AMMOCHARID &. 245 
Drasche (12. pl. ii. fig. 3), who describes it (12. p. 6) as being 
composed of two dorso-ventral lips (facing each other), of 
which each is bilobed, “in a form similar to that of Ascaris” ; 
_the dorsal lip being generally rather the larger. In preserved 
specimens, the two lips are usually found separated from each 
other by about 180°; but in life they are inclined towards each 
other at various angles. 
Where the bases of the two lips touch there is a small deep 
fold, which, however, is cecal and does not lead into the body- 
eavity. The organ is retracted by means of a local folding of the 
centre of its cup-shaped membrane. 
Vou Drasche adds (12. p. 12) that the organ is a folded portion 
of the epidermis, consisting of high, wedged-shaped, badly stain- 
ing, ciliated cells, with small nuclei. As regards preserved 
specimens, I shall not attempt to improve upon this excellent 
description, except to question the existence of the ciliated 
nature of the cells, at all events as regards the upper surface of 
the organ. I have seen it at work many times, and although I 
_ have observed ciliary action on the dorsal lobe and other parts, 
I have failed to detect anything of the kind on its surface. On 
the contrary, the impression, conveyed by watching the living 
animal, is that the function of these tall, transparent cells is 
the secretion of the cement for attaching the outer stony covering 
and strengthening the membranous tube. In certain operations, 
which I hereafter describe, the ventral end of the organ is pro- 
truded between the ventral tentacles, so as to bend far over the 
edge and manipulate the outside of the membranous tube. On 
such occasions the organ presents a beautiful semitransparent 
appearance, with the two protruding terminal lobes, tensely 
distended as from pressure of the secretion with which they are 
charged. A transverse section (Pl. 24. fig. 9) of this end of the 
“ Lippen-organ ” shows that the clear, tall cells, which are so 
noticeable on the upper face, have disappeared from the uniler, 
and given place to much shorter nucleated cells and a folded 
arrangement of the epidermis (/.c.). From the way in which the 
latter structure is protruded, and takes part in the operations 
of the animal, I have no doubt that some of the secretion is 
discharged from its surface, probably near the centre line, below 
the ventral end of the organ, although a discharge may also 
take place feom the upper surface, as is clearly shown in the 
central fold of one of my sections. 
