DUAL CONTROL OF THE LEUCOPHORES IN THE PRAWN, PALAEMONETES VULGARIS, BY PIGMENT-DISPERSING AND PIGMENT-CONCENTRATING SUBSTANCES

¹ Department of Biology, Tulane University, New Orleans, Louisiana 70118, and Marine Biological Laboratory, Woods Hole, Massachusetts 02543

1. The prawn, Palaemonetes vulgaris, produces substances that cause dispersion and concentration of its white chromatophoric pigment.

2. Injection of extracts prepared from one or more eyestalks triturated directly in isosmotic sea water produced concentration of the white pigment alone, dispersion alone, or concentration followed by dispersion. In contrast, similarly prepared fresh extracts of the supraesophageal ganglia with the circumesophageal connectives attached always produced white pigment dispersion alone.

3. Chromatography of ethanol extracts of eyestalks and as well as supraesophageal ganglia with the circumesophageal connectives attached on the gel Sephadex LH-20 always yielded both the white pigment-dispersing substance and the -concentrating substance. The former preceded the latter off the gel column.

4. The responses obtained with extracts prepared directly in isosmotic sea water were interpreted as having been due to the relative quantities of the white pigment-dispersing and -concentrating substances present in the organs in addition to an antagonism between these chromatophorotropins.