"My first examination," says Mr. Bynoe, "of the kangaroo tribe, to any extent, occurred at the Abrolhos; there I had an extensive field for ascertaining the exact state of the uteri of the wallaby of those islands. I opened between two and three hundred, and never found even the rudiments of an embryo; but in the pouch I have seen the young adhering to the nipple from the weight of half a dram to eight ounces and upwards. On examination, the only substance found in the womb when the animal was young and full grown, was a cheese-like substance of a straw colour: I likewise found a similar substance in the pouch around the nipples, and in many instances where the nipples were much retracted, it completely covered them, but it was of a darker hue than that in the uterus, and of a saponaceous or greasy feel; the aperture of the pouch so much contracted as scarcely to admit two fingers; wombs with their cornua remarkably small, and nipples in the pouch scarcely pointing, and in many instances retracted.
"Animals with these appearances, I concluded, had never borne young. Examinations frequently took place immediately after they were shot. In those that had recently discarded their young from the pouch, one nipple and frequently two were found much lengthened, and very often one more than the other. I have seen them in the wallaby frequently two inches in length, and with pouches so large, that you could with ease thrust your hand into them; the uteri with their appendages enlarged and apparently very vascular, as well as thickened; but in no one instance at the Abrolhos could I detect a gravid uterus; but I have seen the young adhering to the nipples less than half an inch in length, and in a perfectly helpless state. It is generally supposed that the uterus in the adult animal is not supplied with much arterial blood, merely sufficient to nourish that viscus. If such be the case, can it have the power of retaining the germ in the womb, when on the most minute examination of the young, I could not detect, by cicatrice or line of abrasion on any part of the abdomen, that they ever possessed umbilical vessels, or had been in any way nourished by a placenta? Let us take into consideration the small size of the animal found in the pouch, its utter helplessness, its slight power of motion, and its firm attachment to the nipple. The more it is in the embryonic state the firmer is its attachment to the mother; to separate it from the nipple requires some force; the surrounding parts of the opening of the mouth, after separation, bleed profusely, and the animal has no power to close it; the opening remains gaping and circular, the animal lies on its side, and if very young, soon dies. On each side of the opening is a line showing the extent of the mouth. When arrived at greater maturity it can make no noise until the mouth is fully developed, and then a faint hissing note; it has no power to stand until very large, and the hair is about to shoot out from the skin. An animal in so helpless a situation could not possibly, with all the aids and contrivances of the mother, attach itself to the nipple and produce adhesion of the oral aperture, when even at a later period it has no motion of life or power to close that opening. The retention in the uterus must be of short duration. I have been led to these conclusions from examinations on the banks of the Victoria River. A flying doe, inhabiting the grass flats, of more than ordinary size, was killed. In thrusting my fingers into the pouch, I found that the mammary glands were remarkably enlarged, pressing forcibly into that cavity. I questioned the seaman who took up the animal, immediately after being shot, whether he had taken the young out, and received a negative answer. Finding the mammary glands so extremely enlarged, I was induced (although pressed for time) to examine the uterus, and posterior and internal parts of those glands--the cornua as well as the other parts of the uterus were much thickened, and apparently highly injected with blood. On opening the cavity I found it throughout thickly coated with slimy or mucal secretion (the only uterus found by me in this state.) I now extended my examination in front of the womb to the posterior part of the mammae, and in doing so discovered a small gelatinous mass, about twice the size of a pea. On a closer inspection, it appeared to be retained in a thin transparent tube. I watched the substance narrowly and could distinctly perceive the rudiments of an animal. The feet were not developed, but pulsation and motion were not only observed by me, but by two of the men with me, both exclaiming "look at the little animal!" although I feel convinced that they did not know what I was searching for. There was not time to examine further into its state. I carefully removed the uterus, the apparent embryo and the mammae, and put it in a wide-mouthed bottle with some spirits, and gave it in charge of the seaman who was to carry a portion of the animal for the dinner of that day. It was placed in a canvas bag, but on crossing a Deep watercourse he had the misfortune to break the bottle, which he never mentioned until the following day. The contents soon dried up and became an uniform mass. The intense heat had rendered it so firm that nothing could be made of it; all the gelatinous parts had adhered so firmly to the bag, that I was compelled to abandon it. My object was to ascertain if there was a communication in a greater state of development between the womb and posterior part of the mammae, during the period of gestation; and I was fancying I had arrived at some conclusion, but all my hopes were destroyed by one fatal smash! So many theories have been formed on that point--that to advance this as a fact, would be treading too firmly on tender ground. At the first view of the gelatinous mass I seriously considered whether it could have been a gland, and whether the pulsation might have been communicated from muscular twitchings; I took my eye off the substance for some time, and on again looking at it, felt more confident than ever, that it was not a glandular substance. Its peculiar configuration and want of solidity proved it indeed not to be gland; its motion, on touching it with the point of the finger, was so much that of an embryonic animal, that I at once, without further investigation, pronounced it a kangaroo.
"Might not the tube I discovered convey the animal to the posterior part of the mammae, where it might become attached to the nipple in an inverted state? At any rate it was not in the body of the uterus. Had the mass been saved I should have taken one more look of inquiry without attempting to alter its structure, and left the matter for the judicious decision of some of the professors of comparative anatomy at home."
It may here be remarked that the birds met with on Houtman's Abrolhos, with the exception of one, resembling in shape and colour a small quail,* were known and common on the mainland. The aquatic species were also familiar to us; but the habit of one kind, of a sooty-black colour, generally called noddies, was quite new--that of building their nests, which are constructed of seaweed and contain only one egg, in trees. There were not many varieties of fish, the most abundant being snappers; of those that were rare Lieutenant Emery made faithful sketches.
(*Footnote. Haemapodicus scintilans, Gould.)
Half a mile west from Slaughter Point we found two caverns similar to that on East Wallaby Island, from which we got three tons of excellent water.
APPEARANCE OF THE REEFS.
The reefs surrounding this group appeared very much broken; and even at Easter Group we had found them to be not so regular as at Pelsart's. This suggests the idea, which appears to be borne out by all we saw, that the reefs are compact in proportion to the exposed position of the islands; the shelter afforded by Pelsart Group, in fact, did not require the reefs to be so united round the other islands to the north.
From the highest part of East Wallaby Island we discovered a patch of land bearing North-West 1/2 North eleven miles. The outer reef extended in that direction from the south-west point of West Wallaby Island, though it could only be traced by detached patches of breakers. To the south-east of its commencement lies Evening Reef. The observations were made on the north end of the north-east Pigeon Island, bearing West by South half a mile from our anchorage, in latitude 32 degrees 27 minutes 21 seconds South and longitude 2 degrees 1 minute 10 seconds West of Swan River, variation 4 degrees 10 minutes westerly. The temperature of Houtman's Abrolhos is rendered equable by the fact that they lie at the limit of the land breezes; during the month we were there the thermometer averaged 71 degrees.
Our protracted stay enabled us to get a tolerable series of tidal observations, which present some singular results. The time of high-water at the full and change was six o'clock when the tide rose 30 inches. It appeared that during the night there was a short flood of six hours with a rise of seven inches, and an ebb of two hours with a fall of only five inches; but that during the day the flow and ebb were nearly equal, the former being eight hours and twenty minutes, the latter eight hours and five minutes, and the rise and fall in each being 25 and 26 inches respectively.