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The epidermis is rather low, about 20 ///, and not very rich in 
giands. The basement membrane is very consistent, looks homo- 
geneous, and shows a friendly reaction to eosin. The poor deve- 
lopment of the muscle wall and the large mass of parenchyma are 
the most noticeable features of the sections. The latter condition 
Text-fig. 6. Ilyplana aberrans. Marginal eyes at the frontal 
end of the body. 45 x. 
Text-fig. 7, Ilyplana aberrans. Cerebral and tentacular eyes. 
The brain and adjacent intestinal coeca also outlined. 40 x. 
reminds one of the conditions met with in some Planocera-species 
(e. g. PI. pellucida). Nor are there a great many embedded giand 
cells emptying their secretion to the epidermis. But besides the 
usual kinds of such giand cells, there are in the peripheral part of the 
body a great number of eosinophilous giand cells, which occur in the 
parenchyma and convey the secretion to the margin. 
The dorsal muscularis does not reach a thickness of 20 //, the 
ventral one not 30 p. I have not previously met with such a feeble 
