42 MR, J.W.CLAEK ON THE NARWHAL. [ Jail. 1 7, 



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 (/. e. 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. Clark, F.Z.S. 



[Received January 17, 1871.] 



In March 1869 I obtained for the Museum of Zoology and Com- 

 parative 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 Copen- 

 hagen 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 16f". Of the tusks 

 the right measures fi' 1" in length, and 8-f" 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 1 7^" apart at their 

 tips. The shorter tusk has evidently been accidentally broken, pos- 

 sibly after the capture of the animal ; had it not been for this un- 

 fortunate 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 f, 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 young 

 Narwhal, it less concerns my 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 Tijdsehrift voor 

 natuurliike Geschiedenis, D. ii. 1835. 



t G-. Vrolik, " Nieuw Voorbeeld van twee uitgegroeide Stoottanden aan den- 

 zelfden Narval Scltadel," in Eijdrage tot de Dierkunde, D. i. 18411. 



% " Nogle Bemaerkninger om Narhvalens Stodtand," Naturhist. Foren. Vi- 

 densk. Meddelelser for 1862. 



§ Dr. G. Jager, "Berichtigung einer Angabe Cuvier's," &c. in Jahresbefte des 

 Yereins fur vaterlandische Naturkunde in Wurtemberg: Stuttgart, 1851. 



