The digestive glands were excised and divided in two portions. One portion was fixed
in Bouin’s fluid (32–36 h), dehydrated, embedded in paraffin and sectioned at 9 mm.
Sections were stained with haematoxylin-eosin (Pearse, 1976) to determine: (i)
stereological measurements, (ii) planimetric measurements and (iii) digestive phases of
the digestive tubules. The second portion was frozen with Bright Cryo-Spray (dichloro-
fluoromethane, 2 50/558C), embedded in Bright Cryo M-Bed and cut in a Bright’s
cryostat at 2 28/308C in sections of 9 mm and stored at 2 708C until used to determine
stereological measurements of the lysosomes.