We have several times caught a triangular, transparent, gelatinous animal; it is 0.18 inch in thickness, and in the outer pulpy gelatinous mass there is an interior sac, and strong muscular bands are marked across this. The sac is composed of three lobes, two of which have apparently no external opening, whilst at the end of the main lobe there is one which closes with a valve; through this I have seen them take in little animals, which reached no farther than the centre, from which the lobes radiate, when the sac became violently agitated, and made strong efforts to expel the foreign substance. This animal was very sensitive, more particularly about the opening of the entrance. We caught today the lower part of the species of Diphyes which we had found on the 13th November 1837, in 30 degrees 7 minutes south latitude, in the Indian Ocean. This animal is thus distributed over a wide range. We also found a very minute species of the animal similar to one which we caught on July 1st 1840. Those we caught today were scarcely 0.05 inches in diameter. They unfolded little wings and flew with them in precisely the way those did which I described on that day. Nothing I have seen is more remarkable than the flight of these little animals; their wings are milk white and very large for their body, and as they fly, the ends, from their pliancy, bend over, which imparts to the motion a very graceful appearance; these wings are composed of a very fine membrane like that forming the wings of a bat. At one time these little animals hovered over a single spot like a bird of prey in the air, flapping their wings in just the same manner. At another time they darted forward with great rapidity, and the vibration of their wings was so rapid that I could not count them. When folded up they look like very minute gelatinous animals with a black internal spot, but when touched their shell can be felt. We saw a shoal of whales today. We have caught lately a great many small animals, of which the following is the description; they swim about from one floating substance to another and are eaten by the little crabs which are numerous in these seas. Length of body 0.18 inch. Length of anterior part of body 0.1 inch. Length of posterior part of body 0.08 inch. Length of tail 0.08 inch. Breadth across back 0.05 inch. Depth from back to bottom of breast 0.06 inch. Head and eyes, deep brilliant prussian blue; body brilliant prussian blue with a bluish green stripe on each side; tail white. Seen through a microscope these animals appear to be a beautiful dark burnished blue mottled with silver. The head is remarkably round and regular.