Zoology Publications from Victoria University of Wellington—Nos. 58 to 61
Tables 1 and 2 summarise the results. Additional features are given below.page 5
The Epidermis: The Feulgen reaction coloured nuclei only. With the methyl green/pyronin test the cytoplasm adjacent to the nucleus often coloured with pyronin (Pl. 1, Fig 1,C). Digestion of sections with RNase for 1½ hrs. reduced pyronin staining, and digestion for 3 hrs. elminated this staining reaction.
The "Basement Membrane": The Allochrome procedure coloured the membrane deep blue.
The Muscles: A small area of cytoplasm around muscle cell nuclei was coloured with pyronin in the methyl green/pyronin test. This colour was removed by digestion of the section with RNase.
The Parenchyma: The parenchyma exhibited an overall dark greyish colour after staining with Sudan black B. Many very small refractile bodies are present throughout the parenchyma, but it is difficult, because of their small size and refractility, to tell whether or not they stain with Sudan black.
A small group of cells situated caudally in the parenchyma immediately behind the penis gave a strong positive result with the Mowry colloidal iron method. These same cells were PAS negative.
The Feulgen reaction demonstrated many nuclei in the parenchyma.
Subepidermal Glands: Two major types of subepidermal gland have been described (Wineera, 1969) for this animal. These are the eosinophil glands and the basiphil glands.
The Eosinophil Glands: Two types are present in P. stephensoni. One type (hereafter termed adhesive glands) was described earlier (Wineera, 1969). The other type (hereafter termed caudal glands) are page 6 located in an area of parenchyma just above the ventral body wall in the caudal region of the worm. The spermathecae and the genital opening also occur in this region of the animal. The glands are intensely eosinophil (Pl. 1, Fig. 6, black material). They contain closely packed granules approximately 1.2μ in diameter, and clusters are found crossing the basement membrane and within the epidermis. With pyronin staining the adhesive gland cells varied from colourless to bright red. The staining could be eliminated by prior treatment of sections with RNase for 3 hrs. Some cells contained colourless secretion granules surrounded by pyronin staining cytoplasm, and others possessed pyroninophil cytoplasmic strands.
The Basiphil Glands: On one occasion basiphil glands displayed metachromasia after staining with toluidine blue and mounting in DPX. The sulphation/Azure A and sulphation/toluidine blue techniques demonstrated metachromasia when the sections were viewed in water. After dehydration and mounting in DPX the colour changed from red to purple. With the allochrome procedure subepidermal portions of the basiphil glands coloured a purplish colour, while the intraepidermal parts coloured red.
Pigment: In paraffin sections the pigment granules are bleached by 10% hydrogen peroxide after 6 days. With 40% peracetic acid made according to Pearse (1960, p.860) the bleaching time was 17 hrs. The colour of the dorsal surface of whole worms was not lessened by extracting them with 5 % hydrochloric acid for 2 weeks. The ultraviolet/fluorescence method of MacRae (1961) for demonstrating the presence of porphyrins in planarians gave negative results. The same test applied to a fresh water triclad gave a positive result.