directed, the oesophagus fitted. The horns or this 

 enterocoele , beginning in "C" to grow over the hydro- 

 eoele, continue the proceso during the rotation of 

 the latter, the- horns or the crescent growing at the 

 expense cf the thickness or its central part , and 

 in "D" we have t&is enterocoele lying directly over 

 the hydrocoele in the form of a perfect horse-shoe. 

 Fig 9. he. 



In the concavity of ^.o hypogaoVr - io -jiite-rooeols 

 is te h - f^rr 1 t n n p ^^rr -r - l 1 , . PT_ J n . 'i i . 



Between the ends of the horns of the hypogas- 

 tric coelom lies the anterior enterocoele, The walls 

 of these structures come together and fuse in such 

 a way that they together form a hollow circular 

 coelom surrounding the stomach and lying over the 

 some what smaller water vascular ring. Fig .9. 



In the four interradii narked by their positions 

 between radial canals l.and 2., 2. and 3 . ,3 ,and4 .and 

 4. and 5. four pouches of the hypogastric entero- 

 coele grow downward, outside the water vascular ring, 

 forcing themselves betv/een the radial canals; a fifth 

 pouch similar to these is formed from the left an- 

 terior enterocoele in the remaining interradius be- 



