36 THE VOYAGE OF H.M.S. CHALLENGER. 



transverse sections are circular or nearly so. The nuclei of the cells of the gland arc all 

 situated at tin' 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 

 -land will have changed into an acinous one. The excrescences nave as a rule the shape 

 of globules, hut 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 arc by no means so uniform as in the ease 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 - l mm. and a breadth of 0026 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 nun. 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 0'13, whereas its breadth was G" ( J mm. It was furnished with a nucleus 0'0.j 

 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 tic cardia in an interspace between two of the so-called hepatic 

 excrescences. 



As fco 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 he doubted thai 

 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 (Verdauungsdriisen) of the higher 

 Crustacea (Isopoda, Amphipoda, Decapoda), we arc -till 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, CJeber den Ban u. die Thatigkeil dei o . Leber der Crustaceen, Arch.f. MiLr. Anal, Bd. .wii. is:u. 



