Figures 1, 2, and 3 represent different views of an animal (Salpa) slightly electrical, that we caught this evening. Figure 1 is its appearance, one side being up; Figure 2 when the other side is turned up; Figure 3 is the side view of it.
I have never before seen one of the kind electrical. Temperature the same as the water, 65 degrees Fahrenheit.
Length, 1.5 inches.
Breadth, 0.6 inches.
Thickness, 0.3 inches.
Figure 1. The intestinal canal terminates in a little coloured bag, generally of a bluish tinge; there is an opening at each extremity, one a little to the left of the little bag, the other, as shown in Figures 3 and 1.
November 13. Latitude 30 degrees 7 minutes south; longitude 100 degrees 50 minutes 10 seconds east.
Figure 1. Represents a little shell (Hyalea) which was caught this day.
Figure 2. One of the tentacula of the animal I imagine to be the Physsophora rosacea. The point which is seen obtruding at the base resembles a little nerve; it runs the whole way down the tentacula.
Figure 3. A little shrimp-like animal (Erichthus vitreus) caught on the 14th November, latitude 29 degrees 26 minutes south; longitude 101 degrees 32 minutes east. Its head was protected by a shield, such as is shown in the figure.
We caught this day several other Acalepha, two of which were of the wonderful genus Diphya. I yesterday drew a coloured figure of the lower part of one of these animals.
This animal in its perfect state (such as we found it in today) consists of two individuals, the part of one being encased in a cavity of the other. Figures 4 and 5 Illustration 4 will give a correct idea of the way in which this junction is effected. The least motion separates these two parts, and each forms a perfect animal, which performs all the functions of life. This is the more extraordinary, as the containing animal is furnished with an organ not possessed by the contained, and which in their united state is used by both. Figure 5. From the little bag (f) at the bottom of the cavity (g) the receiver produces a chaplet, which traverses the canal in the received marked (2) in Figure 6, and which is here drawn the size of life, was sometimes expanded to the length of one foot eight inches. This organ, according to M. Cuvier, is composed of ovaries, tentacula, and suckers.
The swimming apparatus, marked (1) and (4) in Figure 6, act simultaneously; they are of a bright amber colour, and their mouth (a) and (h) are closed with little valves, nearly invisible even when in motion; the points round their upper aperture seem to form the hinges for these. In twenty seconds I counted seventy expansions and dilatations of this apparatus. The chaplet and the bag that holds it are flesh-coloured; the rest of the body is gelatinous and diaphanous. They live in families, and swim with great rapidity in the same manner as the other Acalepha.