1. Watasenia scintillans possesses three kinds of luminous organs, the brachial, the ocular and the integumentary
2. The brachial organ is the best developed and provided with a number of chromatophores around the luminous part. These chromatophores, when the organ emits luminescence, contract and become globular. The reverse is true of the disappearance of light. The luminous part is made up of a number of luminous cells which contain minute rod-like granules. Among the granules the capillaries are found to form a branching or anastomosing system.
3. The ocular organs are all a like in structure and present no dimorphisms. Just in front of the reflector, in the luminous tisau. e, occur numerous granules, which vary in form and size but are of the same character. At the middle of some granules is found a transverse line which may represent the plane of segmentation. The fibrous apparatus is made up of fibrous cells and is of a highly refractive character.
4. The integumentary organs have two kinds of re f l ectors. At the bottom of the funnel-shaped reflector or in front of the posterior reflector is found a cluster of minute spindle-shaped granules, which are homogeneous in appearance.
5. In the three luminous organs the granules, though varying in form and size, have the same affinity with every stain employed and are homogeneous in appearance. They appear to play an important rôle in the production of light.
6. Several efforts were made in vain to demonstrate the distribution of nerve fibres.
7. No trace of bacillus could be brought under my observation.

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