Journals of Two Expeditions of Discovery in North-West and Western Australia Volume II Part 11

Caught a specimen of Glaucus.

Total length 0.35 inches.

Colour down the back deep indigo blue; stomach bluish white; sides bluish white (silvery) like a frog; tail tapering to a point; its head resembled that of a frog, and when out of the water it sat on its tentaculae, and raised its head and the fore part of its body, moving its head (a) from side to side; the tentaculae were all so delicate that they fell off, it had apparently eight on each extremity; it belonged to the same family as the animal I caught on the 14th of November 1837, in south lat.i.tude 29 degrees 26 minutes; east longitude 101 degrees 32 minutes.*

(*Footnote. See Ill.u.s.tration 10 volume 1.)

June 23. South lat.i.tude 32 degrees 53 minutes; east longitude 29 degrees 45 minutes 15 seconds.

We for the first time saw Cape Pigeons and the Albatross.

June 27. ) South lat.i.tude 35 degrees 41 minutes; east longitude 25 degrees 13 minutes 20.

June 28. ) South lat.i.tude 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 cla.s.s; 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 quant.i.ties 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 lat.i.tude 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 gla.s.s 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 lat.i.tude 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 pa.s.sed 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 quant.i.ties 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.

The length of it was 6 feet 2 inches.

Breadth from fin to fin 3 feet 6 inches.

Length from tip of nose to pectoral fin 2 feet.

Thickness through the breast 1 foot 6 inches.

This fish was infested about its nose with a kind of parasite (Lernaea) having two long thin tails. The sailors stated that these animals frequently cause large sores about the nose of the fish, and that when suffering from this, it will allow the sea-birds to sit on it, and peck away at the affected part. The habit of the fish is to swim during calms with one of the hind fins out of water, and it is then harpooned from a boat. I have myself seen petrels perched upon them; and directly one of these fish was hoisted on board the sailors looked for the parasites and found them. Their dimensions were:

Total length 1.0 inch.

Length of tails 0.57 inches.

Ditto of fore part of body 0.25 inches.

Ditto of hind part of body 0.15 inches.

Breadth across body 0.25 inches.

They were covered with a transparent sh.e.l.l, marked with grey spots and lines; the hind part of the body, near the tail, being darker than the fore part, as though the intestines were seated there. These little creatures adhered strongly to any substance that they were laid on, and caused an irritating feeling to the skin if placed on it; they swam with great rapidity when put into seawater, and in their movements in swimming much resembled a tadpole; their tails were merely long transparent fibres.

We caught also several transparent bodies, shaped like a balloon (Beroe ?) These consisted merely of a sac. At the flat end of the spheroid was a small ring of a pink colour, from which ran lines forming the ribs, which supported the sides of the animal. There were eight of these: they possessed great irritability, and if the animal was at all injured, a rapid and continued motion was propagated all along them. Some of these animals were between two and three inches in length, but they were so delicate that it was impossible to examine them, for they fell to pieces directly they were touched. Only one of these ribs was, at times, affected at the same moment, so that they appeared each to be capable of an independent movement.

We caught also many small insects, and some shrimp-like animals.

The sea was full of some things resembling hairs, but which broke the moment they were touched.

On this evening we placed a large number of acalepha in a bucket, and on agitating the water it became a ma.s.s of phosph.o.r.escent light. It is strange that these animals should never emit this light without being irritated.

July 1. South lat.i.tude 35 degrees 51 minutes; east longitude 18 degrees 56 minutes; average temperature of water, 65 degrees.

This day many specimens of different kinds were taken; and amongst them a sh.e.l.lfish (Hyalea) the same as that caught on the 13th November 1837, in south lat.i.tude 30 degrees 7 minutes; east longitude 100 degrees 50 minutes 10 seconds. This fish today put out the apparatus with which it swam. It consisted of two broad transparent wings, shaped like the first pair of wings of a b.u.t.terfly, and which it moved in a precisely similar manner. Its sh.e.l.l was of a delicate pale transparent brown colour, with a jet black spot in the centre. (See Ill.u.s.tration 6 volume 1 Figure 1.) We also caught an animal of a precisely similar form and colour with this, but which was not provided with a sh.e.l.l.

The other specimens were:

1. A sh.e.l.l (Janthina)* the same as was caught on November 14 1837, and on several other occasions, with its swimming apparatus attached.

(*Footnote. The corresponding figure, Ill.u.s.tration 9 volume 1, should have been inverted.)

2. Several of the small sh.e.l.ls which resemble belemnites (Creseis) which were first taken on the 14th November 1837. I this day preserved one of these with its swimming apparatus expanded.

3. An animal without a sh.e.l.l, which had a sort of transparent h.o.r.n.y covering, and when alarmed and not in motion folded itself up.

4. A tube 3.2 inches in length, perfectly transparent, and swelling out to a little k.n.o.b at each extremity; but these k.n.o.bs were of the same colour as the body.

5. Some delicate white sh.e.l.ls (Atalanta) or very hard gelatinous animals, 0.2 inches in length, 0.2 wide, and 0.15 thick; they had three ridges of short spines on them, one down each edge, and one ridge running down the centre of the sh.e.l.l or back.

6. Some perfectly spherical transparent bodies, 0.18 inches in diameter; these neither moved nor showed any signs of life when placed in salt water, but another animal, exactly resembling them in shape and colour, with the exception of having some light brown spots on it, unrolled itself like a wood-louse, and then swam nimbly about. They all turned as white as eggs soon after they were put into spirits.

We caught also several species of an animal with two tentaculae, which had been also taken on the 17th June, some of these were very large and beautiful, being of the most delicate amber colour.

Also many different sorts of medusa, particularly tubes of about 0.5 inches in length, with an apparatus shaped like a proboscis at one extremity of it. These I have not attempted to describe. In general the animals we caught this day differed altogether from those we had hitherto found during this voyage. Some few were the same, but the great majority were new.

Many of the medusae and small gelatinous animals must be endowed with very acute sensibilities and perceptions, for they evinced extreme timidity if any substance approached them, and when plunged alive into spirits, their rapid movements and violent contortions repeatedly indicated acute pain; indeed so clearly that on this point there could be no mistake.

A ma.s.s of gelatinous animals, caught this day, gave out a slight electric shock. Some of them were shaped like the portions of an orange, and they evidently were formed to fit into one another in the manner in which they were found, although they separated directly they were touched.

July 2. South lat.i.tude 35 degrees 58 minutes; east longitude 17 degrees 54 minutes.

This day the s.h.i.+p went so fast that we could not catch anything. The acalephae were not so numerous as they had been further to the north, but we saw more and larger medusae than I had ever before remarked. It indeed appeared as if the acalephae diminished and the medusae increased in number after pa.s.sing the 36th degree of south lat.i.tude.

July 12. ) South lat.i.tude 23 degrees 2 minutes; east longitude 0 degrees 26 minutes 45 seconds.

July 13. ) South lat.i.tude 21 degrees 55 minutes; west longitude 0 degrees 44 minutes.

The vessel went slowly through the water, but although the net was kept towing we could catch nothing, and there was no appearance of anything being in the sea.

July 14. South lat.i.tude 20 degrees 52 minutes; west longitude 1 degree 49 minutes.

This day we caught a Velella of the following dimensions:

Length of interior cartilage 1.1 inches.

Breadth of interior cartilage 0.5 inches.