CHROMATOPHOROTROPINS IN THE CENTRAL NERVOUS ORGANS OF THE CRAB, HEMIGRAPSUS OREGONENSIS

¹ Department of Zoology, Uniyersity of California, Berkeley

1. The melanophores of Hemigrapsus oregonensis become punctate after eyestalk removal.

2. Chromatophorotropins, which cause dispersion of the melanin when injected, are present in greatest concentration in the sinus gland, and are also present in the optic ganglia and possibly in the brain and thoracic mass of ganglia.

3. The melanin dispersion in response to electrical stimulation of the eyestalk stubs and to deep probing with a hypodermic needle indicates that some source of releasable chromatophorotropins exists other than the eyestalks.

4. The total amount of chromatophorotropins in the sinus gland is not necessarily greater than in any of the central nervous organs. The specialized structure and the innervation of the sinus gland suggests that its importance lies in its ability to store and rapidly release effective amounts of chromatophorotropins.

5. Injection of sufficient amounts of certain substances, including muscle and gill extracts and egg albumin solution, also induces melanin dispersion in eyestalk-less Hemigrapsus oregonensis. It is suggested that these substances do not contain chromatophorotropic hormones, but the response to them is the result of a more general stimulation causing the release of chromatophorotropins from central nervous sources.