274 
H. L. M. riXELL. 
gives 126, being in every case over 200 (215 to 230). At the 
base of the tentacular membrane is the very distinct collar 
formed as a fold of the body-wall just behind the nerve-i-iug 
(Figs. 6, 8, 9, 10, r.). This collar is deeper at the sides than 
on the oral surface, and on the anal side it is interrupted by a 
bifid process, the anal papilla, into which the trunk ccelom is 
continued, and which is divided internally by the rectal 
mesentery suspending the shoi't terminal rectum (Fig. 11). 
Text-fig. 8. 
iL.hP^,.^ 
Longitudinal section throngli the collar and base of loiiliophore 
in front of anal papilla. ( X 40.) 
The lophophoral org’an (Figs. 7 and 8 l.n.) is extremely 
variable; in some specimens it was lai-ge, and apparently 
similav to that described for Ph. psammophila by Cori (3) 
and for Ph. cajiensis by Glilchrist ([7j p. 158). The inner 
leaf-like fold forms a covered passage from close to the 
nephridiopores forwards and outwards into the lateral lopho- 
phoral spaces, which are lined by thick glandular epithelium. 
This epithelium also extends up the inner side of the tentacles, 
and has been seen by Gilchrist to secrete mucus b}' which the 
