Quarterly Journal of Microscopical Science, Vol s2-87, 209-235, Copyright © 1946 by Company of Biologists

Memoirs: The Tegumental Glands in the Land Isopoda A. The Rosette Glands

¹ Department of Zoology, University of Bristol

1. The land Isopoda possess five (or possibly six) distinct varieties of tegumental gland, and these are briefly described. Of these, only the rosette glands are known to occur outside the group.

2. The rosette glands of the Isopoda are similar to those of the Deeapoda, but are confined to the head and mouth-parts. The structure and development of the rosette glands in Porcel-lio scaber Latr. are described.

3. Activity is intimately connected with the moulting cycle, the glands reaching maturity and liberating their secretion only during the few days before ecdysis.

4. The contents of the glands and their ducts show the same staining reactions as the cuticle.

5. The cuticle first appears after the formation of new chitin has begun and increases in thickness with it.

6. The thickness of the cuticle is greatest in the mouth-parts, where the ducts of the rosette glands open.

7. The function of the rosette glands in the Isopoda is similar to that of the corresponding glands in the Decapoda, namely to secrete the layer of cuticle on the surface of the integument.

8. Seven other species of Isopoda, from a wide range of habitat, were examined. Rosette glands similar in structure and distribution to those of Porcellio, and presumably having the same function, were found in every case.