240 
left three rounded cells, cne of which is vacuolated, the 
other two contain chlorogogen granules. These may be 
amceboid cells which had temporarily withdrawn their 
pseudopodia. x LOO. 
Fig. 45. A portion of the third diaphragm, from a 
stained preparation, to show the numerous oval apertures 
by which the septum is perforated. The diaphragm is 
covered on both faces by a flattened endothelium between 
which isa thin layer of connective tissue and inter-crossing) 
muscle fibres. The endothelial nuclei of one face only are 
shown. x 300. 
Puate VI. 
Fig. 46. Dissection of anterior end of large 
specimen, with pharynx and the first diaphragm removed, 
showing anterior and posterior lobes of brain; middle 
cerebral region of each side connected by broad band of 
nervous tissue; nerve to otocyst arising from cesophageal 
connective; muscle strands from otocyst to body wall; 
anterior portion of ventral nerve cord; first notopodial 
sacs and muscles; the longitudinal muscles and the buceal 
sheath. x 6. 
Fig. 47. Horizontal section of prostomium of a 
specimen 60 mm. long. The anterior and dorsal portions 
of anterior lobes of the brain are formed largely of pyri- 
form ganglion cells shewn diagrammatically in the figure. 
Three coelomic spaces, lined by coelomic epithelium and 
containing blood-vessels, are seen. On the anterior left 
side of brain is an eye slightly exaggerated. The posterior 
lobes of the brain underlie the nuchal organ, most of their 
nerve cells are small and their nuclei only are shown. 
The middle region of the brain, consisting largely of 
neuropile (finely punctate), shows a transverse band of 
fibres connecting the right and left halves, Attached to 
