The endocrine system of lower crustaceans such as anostracan
also shows a similarity with that of decapod crustaceans, especially
in the possession of a stalked eye in which is present the
X-organ sinus gland complex (Lake, 1969). In the fairy shrimp
Streptocephalus dichotomus, the sinus gland is located inbetween
the lamina ganglionaris and the optic medulla. The cells
in this gland show variation in their secretory contents during
reproductively quiescent and reproductively active period