Some Notes on Alcippe lampas (Hanc.). 189 
fact to find anything in their neighbourhood that could be considered 
a sensory epithelium. 
The mantle itself, its form in young and adult animals, its 
armature etc. has been sufficiently described by the various authors 
and its homology with the mantle of the Lepadidae and Balanidae 
has been discussed. So has the disk. 
To the description of the histology of the mantle I have to offer 
a little addition. An area of peculiar cells is seen at the base of 
the gill lamella (Fig. 17) where it joins the mantle. It is on the 
surface towards the animal’s body and continues for some distance 
into the adjoining portion of the mantle itself. Here we find all 
the subcuticular cells elongated and grouped together into tapering, 
tent-like masses. The end adjoining the cuticle is lighter, coarsely 
granular, sometimes with a vesicular network. The nucleus is large, 
oval, with a nucleolus and a distinct chromatin network. It lies in 
the lower half of the cell. Away from the base each cell tapers 
and its protoplasm gets finely granular and stains very dark, esp. 
with haematoxyline. Finally each cell ends into a fine, dark, thread- 
like structure. These threads pass in bundles through the rest of 
the tissue of the lamella, spread again and attach themselves to the 
cuticle of the opposite side right among the subcuticular epithelial 
cells of the outside in the mantle, of the side away from the animals 
body in the gill. Towards the ends of the area (in the gill and in 
the mantle) the cells are lower, but they still form the tent-like 
eroups and stain very deeply. The common epithelium then begins 
all at once. In the centre of the area, that is to-say just where 
the gill joins the mantle, the cells seem to be densest and highest. 
These cells evidently take the place of the groups of thread-like 
supporting fibres present everywhere in the mantle and gill and 
described and figured by Berxpr. But whether they are really or 
only supporting in nature, or whether they have another function I 
am unable to say. They stand out distinctly in all my sections 
through the region, but show especially well in those stained in 
EaHrLicH’s haematoxyline after fixation in HgCl,. A slide of the 
same series was after staining with Enruicu’s haematoxyline treated 
with xylol containing picric acid. Here while all the muscle fibres 
of the mantle are bright yellow, the “supporting” fibres of the gill 
and mantle and the fibres just described are dark blue. In the 
cells themselves of -our area the karyotheca, chromatin and nucleolus 
