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Art. XIII.—On the Occurrence of the Luth, or Leathery Turtle, on the Coasts of New Zealand.
[Read before the Auckland Institute, 25th July, 1892.]
About the end of May in this year several paragraphs appeared in the local newspapers respecting a marine animal captured off the Bay of Islands by Captain Subritzky, of the schooner “Medora.” At first I took the statements to refer to an unusually large specimen of the green turtle (Chelonia viridis), a species which is plentiful in many parts of Polynesia, and in tropical seas generally, and which frequently wanders so far from its ordinary habitats as to be seen off the northern coasts of New Zealand. But I was assured that this was not the case; and, as Captain Subritzky brought his specimen to Auckland for exhibition, I took an early opportunity of inspecting it. I had then no difficulty in identifying it with the luth, or leathery turtle (Sphargis coriacea), the largest of all living chelonians, and one which has never before been noticed in our seas. As some little interest attaches to the discovery
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of animals in localities widely separated from their usual home, I propose to put on record the facts connected with its capture.
Captain Subritzky informs me that on Sunday, the 22nd May, when passing Cape Brett on a voyage from Awanui to Auckland, he noticed a floating object, which he at first took for a boat bottom upwards. The schooner's boat was lowered, and he proceeded to inspect it; when, to his astonishment, it suddenly disappeared, shortly afterwards reappearing a little distance further away. Returning to his vessel, he secured a harpoon and line, and then pulled cautiously up to the creature, soon recognising it to be a large turtle-like animal entirely new to him. After a little manœuvring he succeeded in harpooning it in the neck. According to him, it made a most determined resistance, making for the boat open-mouthed, snapping its jaws violently. It succeeded in getting its flappers over the side of the boat, nearly capsizing it, but was stunned by a blow on the head, towed alongside the schooner, and hoisted on board.
Good descriptions of the luth are given in many wellknown books on zoology, so that it is quite unnecessary for me to give any lengthy account of it. I will only say that it differs from all the other sea-turtles in the body not being covered with hard plates, but with a thick leathery skin, which is quite smooth when the animal is adult, with the exception of seven conspicuous longitudinal ridges, but is covered with tubercular scales when very young. As I have already said, it is the largest of living turtles. Specimens over 9ft. in length, and weighing nearly 1,800lb., have been captured. Captain Subritzky's specimen is much smaller, its total length being a little over 6ft., but, from the longitudinal ridges showing a few tubercular projections, it is probably not yet adult. Its measurements are as follow:—
| Ft. | in. | |
| Length of carapace | 4 | 7 |
| Breadth ” | 2 | 9.½ |
| Depth | 1 | 3 |
| Length of head | 0 | 11½ |
| Breadth ”0 | 0 | 10½ |
| Depth ” | 0 | 8½ |
| Diameter of eye | 0 | 1 |
| Diameter of orbit | 0 | 2 |
| Length of anterior paddle | 2 | 11 |
| Width of same (greatest) | 0 | 10½ |
| Length of posterior paddle | 1 | 6 |
| Greatest width of same | 0 | 9½ |
| Total length of animal | 6 | 1 |
| Diameter from tip to tip of the expanded paddles | 7 | 6 |
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The proper home of the luth is in the warmer parts of the Atlantic, Indian, and Pacific Oceans. Its enormous paddles give it great swimming-powers, and it consequently ventures far out to sea, and sometimes strays to very distant localities. Specimens have been stranded on the coasts of France and Holland, and one or two have reached England. In the temperate parts of the Southern Hemisphere it has only once been noticed—in 1862, when a half-grown specimen was captured at Portland, on the coast of Victoria. Probably both that and the one now under consideration have wandered from the Polynesian islands, where it is said to be occasionally seen, but never in large numbers.