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Show 42 MR. J.W.CLARK ON THE NARWHAL. [Jail. 17, who had correctly determined the species (cf. Nouv. Arch. d. Mus. ii. p. 265). But so long as the true Axolotl of the lake of Mexico (Siredon mexicanus) was never known to undergo any metamorphosis, it seemed to be too soon to arrive at one of the conclusions put forward by Prof. Dumeril (I. c. p. 291) that the name Siredon must be altogether suppressed. No Amblystoma was known, according to Prof. Baird, to which Siredon mexicanus could possibly be referred. The following papers were read :- 1. On the Skeleton of a Narwhal (Monodon monoceros) with two fully developed Tusks. By J. W . C L A R K , F.Z.S. [Received January 17, 1871.] In March 1869 I obtained for the Museum of Zoology and Comparative Anatomy at Cambridge, through the kindness of Professor Reinhardt of Copenhagen, a complete skeleton of an adult Narwhal, with both tusks fully developed. It had been brought to Copenhagen from Greenland a few weeks before by one of the officers of the Danish establishments there, and reached me in a very rough state, just as it had been hastily cleaned in the first instance. The skeleton is complete, with the exception of the pelvic bones, and measures from the central point of the tail-flukes to the ends of the maxillaries 14', of which the skull occupies 22". The greatest breadth of the skull across the squamosals is 16|". Of the tusks the right measures 6' 1" in length, and 8|" in girth at the outer edge of the socket; the left 6' 7", with a girth of 9|". The tusks are 2\" apart at their origin, but diverge until they are 17-§" apart at their tips. The shorter tusk has evidently been accidentally broken, possibly after the capture of the animal; had it not been for this unfortunate circumstance, they would have been as nearly as possible of equal length. The sex was not stated ; but there can be but little doubt that the skeleton is that of a male. There are four excellent papers on the dentition of the Narwhal- by Mulder*, G. Vrolik t, Reinhardt J, and Jager §. The first two being in Dutch, and the third in Danish, they are little known. I owe a translation of Reinhardt's to the kindness of Professor Flower ; of Vrolik's I have had one made. I regret that I could not obtain one of Mulder's ; but as it chiefly relates to the dentition of the youn°* Narwhal, it less concerns m y present purpose. Vrolik and Reinhardt both treat of bidental skulls ; and so does Jager to a certain extent. * Claas Mulder, " Over de tanden van den Narwal," &c. in Tijdsch rift voor natuurlijke Geschiedenis, D. ii. 1835. t G. Vrolik, " Nieuw Voorbeeld van twee uitgegroeide Stoottanden aan den-zelfden Narval Schadel," in Bijdrage tot de Dierkunde, D. i. 1849. J " Nogle Bemaerkninger om Narhvalens Stodtand," Naturhist. Foren. Vidensk. Meddelelser for 1862. § Dr. G. Jager, "Berichtigung einer Angabe Cuvier's," &c. in Jahrcsheffe des \ ereins fiir vaterlandische Naturkunde in Wurteinberg: Stuttgart, 1851. |