Some Account of the Dugong. By Sir Thomas Stamford Raffles, Governor of Sumatra. Communicated in a Letter to Sir Everard Home, Bart. V.P.R.S. Read May 18, 1820. [Phil. Trans. 1820, p. 174.]
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The form of the Dugong resembles that of the common Cetacea. The skin is smooth and thick, with a few scattered hairs, and the head small in proportion, with two short tusks projecting from the extremity of the upper jaw. The place of the incisors is substituted by the rough bristly surfaces of the palate and jaws, which enable the animal to browse upon marine vegetables. There are twelve cylindrical molares, with flat crowns. The aperture of the ears is remarkably small. There are no dorsal or ventral fins; but the place of the anterior extremities is supplied by fins, which, however, are not capable of supporting the animal when out of water.
Upon dissection, the skin was found three quarters of an inch thick. The stomach has two appendages opening into it, near the junction of the duodenum; the intestinal canal is long; the liver has two large and two smaller lobes, one of which is tongue-shaped and covers the gall-bladder; the kidneys are large, and the urinary bladder probably capable of considerable distention; the testicles are placed a little below the kidneys; the urethra opens in a small tubercle between the two lobes of the glans penis.
In the thorax the thymus gland is large, black, and friable; the lungs not lobulated ; and the ventricles of the heart, being separated at their points, give it a double appearance.
In regard to the skeleton, the head is remarkable for the manner in which the anterior part of the upper jaw bends downwards, the lower jaw being proportionally truncated. There are fifty-two vertebrae, eighteen ribs on each side, and the sternum is bifurcate at the apex, and articulated to the cartilages of the upper ribs. There is no pelvis nor posterior extremities, but opposite the eighth or tenth lumbar vertebra are two narrow flat bones, lodged in the flesh, one on each side. The scapula is thick, and the humerus, radius, and ulna, short and strong.
The flesh of this animal is delicate and juicy, resembling young beef. It is only found in shallows and inlets of the sea, and the greatest number is said to be taken during the northerly monsoon, near the mouth of the Johore river, in the inlet of the sea between Singapore island and the main; they seldom exceed eight or nine feet in length, though they probably grow much larger, but are then too strong to be caught.
— Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London (From 1800 to 1830 Inclusive), 1833
According to Wikipedia they rarely exceed 10ft in length, and the largest recorded specimen was 13ft 4in. I have to wonder if Raffles knew enough biology to prepare this report himself, or if he was passing on someone else’s findings.