526 F. M. MacFaArranp, 
lining of the esophagus is made up of high columnar ciliated cells, 
while that of the stomach is much lower and for the greater part 
is likewise ciliated. No trace of anything resembling a gastric ar- 
mature can be found, and the small spines observed by Euior (1905) 
are undoubtedly foreign material. Into the stomach about midway 
of its length open the two wide ducts of the liver lobules, one the 
more anterior, upon the upper, right side, the other, midway of the 
left side in the upward curvature of the organ. The liver is lobu- 
late, but the lobules are limited to the visceral complex and present 
smoothly ceurved external surfaces, there being no trace of any ra- 
mifications extending into or even toward the cerata, such as are 
found in nearly all other Aeolidiadae. Four principal lobes may 
be distinguished, which are in turn more or less clearly subdivided 
into lobules. These are the following. 
1. Antero-dorsal lobe, situated upon the left anterior end of the 
visceral complex. Its convex external surface is triangular, it being 
wedged in between the anterior end of the stomach, its pylorie end, 
and the beginning of the intestine. At its posterior end it opens 
into the stomach by a broad duct, which also receives the duct of 
the posterior lobe of the liver. 
2. Posterior lobe. This largest division of the liver is approxi- 
mately pyramidal in form, the obliquely concave base being directed 
forward and in contact with and overlapping the posterior portion 
of the greater curvature of the stomach. The apex is bluntly 
rounded, and forms the posterior end of the visceral complex. The 
posterior lobe is in turn divided into four lobules, one of which, 
the more dorsal and anterior, is clearly separate from the remainder, 
its duct, however, joining the main duct of the lobe. The antero- 
ventral lobule is less clearly marked off externally, while the two 
posterior lobules appear to be fused, until carefully separated, when 
each is found to have a separate duct, all uniting together into one 
main posterior duct which opens as above described. 
3. The dorsal lobe of the liver lies in the upper anterior portion 
of the visceral complex, and bears a deep, transverse groove in 
which the anterior loop of the intestine lies. Its ventral face rests 
upon the upper and right side of the stomach, into which it opens 
by a wide duct on the upper right side, which is also joined by 
the wide duct of the remaining lobe. 
4. The ventro-anterior lobe lies obliquely across the lower 
anterior face of the visceral complex. Its right border is in con- 
