THE HISTOGENESIS AND CYCLIC PHENOMENA OF THE SINUS GLAND AND X-ORGAN IN CRUSTACEA

¹ Woods Hole Oceanographic Institution and Department of Biology, Rensselaer Polytechnic Institute, Troy, New York

1. The histogenesis of the sinus gland and X-organ have been studied and described for the egg, first zoea and adult stages of Pinnotheres maculatus.

2. The sinus gland is not found in the egg or first zoea, but it is found in all the adult stages of Pinnotheres.

3. The X-organ is found in the egg and other stages of Pinnotheres.

4. The histogenesis of the sinus gland and X-organ have been studied and described for the egg, first four stages after hatching and the adult of Homarus americanus.

5. The sinus gland is not found as a definitely discernible structure in Homarus until the third stage after hatching.

6. The X-organ is found in all stages of Homarus that have been studied.

7. Evidence is presented for the existence of cyclic secretion phenomena in the sinus gland of all species studied.

8. There is no evidence of the existence of cyclic secretion phenomena in the X-organ in any of the species investigated.