A sexual dimorphism of the harderian gland of the toad, Bufo viridis.

The Harderian gland of the toad, Bufo viridis, is an acinar gland located at the medial corner of the orbit. The columnar glandular cells show considerable variation in height depending upon their functional state. During July they are taller than in November and May, and filled with secretory seromucous granules. The glandular cells of the female toad, only, contain at their base numerous lipid droplets dispersed in a smooth endoplasmic reticulum. This is the first observation of sexual dimorphism in the Harderian gland of a nonmammalian vertebrate. The secretion of the gland is mainly merocrine. Although the secretion of the Harderian gland is mainly concerned with lubrication of the eyeball, the presence of lipid secretion only in the female glandular cells suggests a pheromonale function, which may influence the sexual behaviour of the male.