Spermiogenesis and cellular associations in the seminiferous epithelium of the guinea fowl were studied and described in "sexually" active adult birds. PAS stain was found to be useful in the recognition of steps of spermatid differentiation only in the first early stages. Nuclear morphological changes were subsequently found to be more reliable in tracing steps of spermiogenesis. It was observed that haematoxylin-eosin stained tissue can be used in the study of spermiogenesis in the bird. Various stages of the seminiferous epithelium were observed in any cross-section of the seminiferous tubules. Distinct cellular associations were observed, but intermix of adjacent germ cells or heterogenous cellular associations were frequently encountered.

Summary Results of the physical and chemical analysis of the gizzard contents in Numida meleagris galeata (Pallas) shot in the natural areas of the Kainji Lake Basin, in the Nigerian Savanna are presented. The consumption of hard and bulky food items was positively correlated with ingestion of small pebbles and sand grains which aid the gizzard in grinding food. The mean fresh weights of gizzards and gizzards' contents of N. m. galeata were as follows: fresh gizzard, 38.0 ± 10.0 g; empty gizzard, 21.8 ± 7.2 g; food content, 11.2 ± 4.7 g; and pebbles 3.3 ± 2.0 g. Résumé On présente les résultats d'analyses physiques et chimiques des contenus du gésier de Numida meleagris galeata (Pallas) tirés dans les zones naturelles du Bassin du Lac Kainji, dans la savane nigériane. L'absorption de types de nourriture dure et volumineuse est en corrélation positive avec l'ingestion de petits cailloux et de grains de sable qui contribuent à l'abrasion de la nourriture dans le gésier. Les poids moyens des gésiers et de leur contenu chez N. m. galeata sont les suivants: gésiers complets, 38.0 ± 10.0 g; gésiers vides, 21.8 ± 7.2 g; contenu alimentaire, 11.2 ± 4.7 g; cailloux, 3.3 ± 2.0 g.

The role of thyroid hormones on parietal cell function and number was studied in the rat. Chronic administration of thyroxine (6-8 micrograms/100 g body wt/day) for 35 days significantly increased parietal cell mass (from 21.18 +/- 0.13 x 10(6) to 26.71 +/- 0.14 x 10(6] as well as basal acid secretion (from 3.69 +/- 0.08 to 4.99 +/- 0.16 mueq/10 min) and histamine-stimulated acid secretion (from 2.45 +/- 0.12 to 3.69 +/- 0.21 mueq/10 min). Thyroidectomy decreased the number of parietal cells in the gastric mucosa (to 10.48 +/- 0.09 x 10(6] and basal acid secretion (to 3.09 +/- 0.08 mueq/10 min). Histamine (0.2 mg) injection into the thyroidectomized rats increased acid secretion by only 1.41 +/- 0.06 mueq/10 min as against 2.45 +/- 0.12 mueq/10 min obtained for control rats. The results suggest that thyroid hormones regulate basal and secretagogue-stimulated acid secretion via their effects on parietal cell mass.

No abstract