A dark adapted specimen of Mnemiopsis, when subjected to the action of the galvanic current, reacts by a display of luminescence at the anode. In lively specimens the glow may extend to the middle of the animal, and last for as long as five seconds. The instant the current is broken the glow at the anode ceases and a momentary flash occurs on the cathodal side of the animal. These effects are observable whether the current be passed through the animal lengthwise or transversely. If a transverse incision be made in a specimen of Mnemiopsis, then, when the current is passed longitudinally through the animal, in the region of the cut surfaces luminous secondary anodes or cathodes appear whenever the animal is subjected to the make or break of the current. The reaction of Mnemiopsis to the galvanic current therefore constitutes a complete case of “reversed Pfluger's law”. The same phenomena may be demonstrated with specimens of Beroe, except that the effect of the break shock is not apparent in a luminescent ...