Gastrulation in the housefly,Musca vicina,macquart

Résumé L'«innere blastemma» de l'uf de la mouche domestique est riche en acide ribonucléique et en glycogène. Ce stratum s'incorpore dans le blastoderme et le mouvement gastrulaire commence peu après, avant même que la délimitation des cellules soit complète. La signification de ce caractère est soulignée.     

Phosphomonoesterases in the 2 sexes of the root-knot nematode,Meloidogyne lucknowica Singh, 1969

Summary The 2 phosphomonoesterases of the root-knot nematode were colorimetrically determined. Alkaline phosphatase activity was observed to be lower than the acid phosphatase activity. Sex related trends were clearly seen in the enzyme levels of the 2 sexes of thenematode. Alkaline phosphatase level differed 28.76%, while acid phosphatase level differed 60.36% in the 2 sexes.The authors are grateful to the Council of Science and Technology U.P. for the grant of a Research Scheme for these studies.     

Giant collagen fibres in the gonopodium of the mosquitofishHeteradria formosa,Agassiz, 1853 (Pisces,Poeciliidae)

Summary The gonopodium of the mosquitofishHeteradria formosa was studied by transmission electron microscopy. In cross-section the gonopodium shows the following structure from the outside inwards: mutilayered epidermis, basal lamina and central supporting tissue, in which vessels and nerves are embedded. At the top of the gonopodium giant collagen fibres are found, which measure up to 150 m in length and 6 m in diameter. These fibres reinforce the gonopodium.This research was supported by the Deutsche Forschungsgemeinschaft. Address for reprints: Forschungsgruppe Dermatologie der Universität Heidelberg, Im Neuenheimer Feld 324, D-6900 Heidelberg.