NUDIBRANCHIATA OF THE IL.M.B.C. DISTRICT. 103 
entirely without the aid of thin serial sections, then it 
is not surprising that they have been led into error. 
Our figure 1 on Plate XII. shows a dissection of Dendro- 
notus from the left side, exhibiting distinct prolongations 
from the liver extending upwards towards the base of the 
rhinophore and the two succeeding dorsal processes ; and 
as further dissections show distinct cavities branching 
through these processes, it is not unnatural to suppose 
that such cavities are the continuations of the hepatic 
ceca. This, however, is not the case. In our serial 
sections we can trace the hepatic prolongation towards the 
rhinophore forwards through sixty-six sections, gradually 
narrowing until it ends blindly, the last section passing 
through its anterior wall. At this point it has not nearly 
reached the base of the rhinophore. Similarly we can 
trace backwards the next hepatic prolongation in the 
sections till we reach its blind extremity, which is in the 
body wall vertically below the first dorsal papilla. 
On the right side of the body we can also trace the 
hepatic ceca going some way towards the rhinophore and 
the two succeeding cerata, but not entering any of these 
processes. 
- In the sections of the cerata themselves we find :— 
(1) Large spaces in the mesoderm, containing blood 
corpuscles (Pl. XII., figs. 2 and 3, c.s.). These run, in the 
main, longitudinally. They occasionally branch, and they 
open into innumerable minute lacune in the mesodermal 
tissues, all of which here and there contain blood cor- 
puscles. 
(2) A good deal of pigmented connective tissue forming 
branched masses and ramifying threads of a brownish 
colour. These frequently, in a surface view of the terminal 
branches of the cerata under a low power, give rise to 
the appearance of a dark coloured granular central cecum 
