Videnskabelige meddelelser

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Videnskabelige meddelelser

168

Litteratur.

Arendsen Heins: Contributions to the anatomy of Monodon Monoceros.

(Verh. d. koningl. Akad. d. Wetenschapen te Amsterdam. 1914).

R. Brown: On the Cetaceans of the Greenland seas. (Proc. Zool. Soc. Lon-

don. 1868).

J. W. Clark: On the skeleton ,of a narhwal with two fully developed tusks.

(Proc. Zool. Soc. London 1871).

W. Kiikenthal: Vergleichend anatomische und entwicklungsgeschichtliche

Untersuchungen an Waltieren. (Denkschr. med.-naturw. Ge-

sellsch. Jena 1889—93).

— Die Wale der Arktis. (Fauna arctica. I. 1900).

M. P. Porsild: Om nogle vestgrønlandske Pattedyr og Fugle. I -II. (Medd.

om Grønland. LVI. 1918).

J.Reinhardt: Nogle Bemærkninger om Narhvalens Stødtand. (Vid. Medd.

Naturh. Foren. f. 1862, 1863).

Scoresby: Journal of a voyage to the northern whale-fishery. London. 1823.

Summary.

715 single tusks and 6 crania with two fully developed tusks

were examined ; they were without exception sinistrorsal. The faet

that the tusk of the narhwal so constantiy is sinistrorsal, is in

favour of Reinhardt's hypothesis, that there is the same course to

the sinistrorsal asymmetry of the skull of the whales and the

sinistrorsal twistling of the tusk of the narhwal. It is obvious that

all the tusks are worn at the apex, a faet to whieh also Porsild

ealls attention; and a great number of tusks were broken. Among

129 tusks from Cape York 28 were broken near the base, 34

more distally, only 67 were quite unbroken ; this implies, that the

tusk is very fragile. Often the apex was weared round and regu-

lar, but often the wearing was more intense on one side, and there

was then a slight concavity. When broken near the base the rup-

ure was more irregular. When there were two fully developed

tusks but of unequal length, they were both weared. 1 think it

will be difficult to explain this wearing without adopling the old

hypothesis, that the narhwal with the tusk root the sea-bottom in

search of the food.

24-1—20.

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