June 27. ) South latitude 35 degrees 41 minutes; east longitude 25 degrees 13 minutes 20. June 28. ) South latitude 35 degrees 15 minutes; east longitude 23 degrees 26 minutes. Upon these two days we were in a rapid current, which we entered on the morning of the 27th, and on neither could we see the slightest signs of any of the acalepha class; but on the 29th, on which day we experienced no current, we found the greatest abundance of these animals; it appeared as if they had collected in large quantities at the edges of the current; and on the western side of it we found many animals which I had not seen on the opposite one. June 29. South latitude 35 degrees 31 minutes; east longitude 22 degrees 20 minutes 30 seconds. The specimens caught were a minute fish, 0.35 inch in length; colour, back and upper half of sides, deep indigo; belly and lower half of sides, silver colour. Also two sorts of barnacles (Anatifa) which I got near the side of the vessel. We caught today a great number of the animals (Glaucus) I have mentioned above as having been taken on the 17th of June, as well as on other occasions. I observed these animals in the water, and found that their long silk-like antennae had, when uninjured, a length of five or six inches; they swim with the rounded part first, and the long antennae trailing after them like tails; the progressive motion is produced by introducing water into certain sacs, or cavities, and expelling it by a contraction of the muscles with great violence. I observed their motions from a boat at first, and afterwards when they were in a glass of water. I counted the number of times they expelled water in a given time when swimming, and found the mean of several observations by a chronometer to give ten strokes in twelve and a half seconds. We caught again many little animals which I had found on the 15th of October 1837; south latitude 37 degrees 28 minutes, east longitude 21 degrees 19 minutes; they were shaped like an octagonal crystal, terminating in a point, containing a brilliant blue colouring matter, they were about 0.4 inches in length, and were, when undisturbed, arranged in long strings, only the length of a single animal in thickness, and of the breadth of two of them abreast; they swam with the blue-pointed ends downwards, which then looked at a distance like the legs of a caterpillar, and the long string somewhat resembled a long gelatinous band in appearance as it passed through the water; but directly it was touched the animals separated themselves from one another. These strings were sometimes seen several feet in length. We caught large quantities of these animals at one time, and found: The temperature of the water 65 degrees Fahrenheit. The temperature of the air 75 degrees Fahrenheit. The temperature of the animals 66 degrees Fahrenheit. We caught also a fish (Orthogariscus) which the seamen called a devil-fish.