THE VOYAGE OE H.M.S. CHALLENGER. 
36 
transverse sections are circular or nearly so. The nuclei of the cells of the gland are all 
situated at the periphery close to the membrana propria which envelops the body of the 
gland. 
The structure of the gland in Lepas will now be easily understood. Let the wall of 
the gland in Scalpellum develop excrescences, so that the interior of each excrescence 
communicates with the interior of the original or main part of the gland, and the tubular 
gland will have changed into an acinous one. The excrescences have as a rule the shape 
of globules, but they may also be elongated so as to form finger-shaped appendages. When 
the gland is divided by transverse and parallel sections in a series of preparations the 
shape and size of the cells are by no means so uniform as in the case of Scalpellum. This, 
of course, is partly in consequence of the sections not always cutting the cells in the 
same direction, though parallel. In some of the sections the cells are cylindrical, having 
a length of OT mm. and a breadth of 0*026 mm. If these same cells had been cut 
transversely to their longest axis, their length would have appeared much shorter. The 
size of the oval nuclei is 0*016 mm. In the more tubular parts of the gland the cells are 
not so high and their walls not so parallel ; in the sections, therefore, they are almost 
triangular or flattened quadrangularly ; between them I observed here and there larger 
cells with very capacious nuclei. I measured one of the cells, the length of which 
was 0T3, whereas its breadth was 0*9 mm . It was furnished with a nucleus 0*05 
mm. in diameter. The only difference which I could make out between the different 
cells of each gland was, however, in size ; in regard to their staining with aluminium 
carminate, I must point out a very striking correspondence of these cells to those of 
the cement-apparatus of the peduncle, viz., the body of the cells is always beautifully lilac- 
coloured, the nuclei appearing dark violet. The latter are remarkable, in the same way 
also as those of the cement -glands, since coarse granules and even fibres fill their 
interior. A distinct membrana propria surrounds the body of the gland in Lepas as well 
as in Scalpellum. 
The gland communicates with the interior of the stomach by means of a narrow duct 
which opens close to the cardia in an interspace between two of the so-called hepatic 
excrescences. 
As to the function of these glands a few words may suffice. That they are not true 
salivary glands needs no further proof. At the same time it can hardly be doubted that 
their function is that of a digestive organ which pours its secretion into the alimentary 
canal. Whereas the recent interesting researches of Max Weber 1 have cast light upon 
the structure and function of the digestive glands (Yerdauungsdriisen) of the higher 
Crustacea (Isopoda, Amphipoda, Decapoda ), we are still almost entirely ignorant of their 
occurrence, functions, structure, &c., in the different orders of Entomostraca. The 
supposition of Claus, that the name of liver in invertebrate animals has often been used 
1 Max Weber, Ueher den Bau u. die Thatigkeit der sog. Leber der Cruataceen, Arch. f. Mikr, Anat Bd. xyii. 1879. 
