360 A. Ärnbäck Christie-Linde 



the foetal Echidna. As to this structure in the adult animal I have 

 only found a Statement in Broom's paper. Broom mentions that 

 »this portion of the nasal floor cartilage outside the naso-palatine 

 canal is formed as a mere rudiment, which might readily escape 

 the eye instead of the broad plate seen in the young condition«. But 

 the posterior part of the plate remains and is well developed alsa 

 in the adult Echidna. 



According to Seydel the cartilago palatina in Echidna has a 

 special function in the development of the skull : the foramen naso- 

 palatinum is formed by this plate separating off the anterior end 

 of the fenestra basalis, the posterior and larger part of which is 

 shut up by the secondary palate. Through this foramen a com- 

 munication between the nasal and buccal cavities remains during^ 

 the whole life viz. canalis naso-palatinus. The cartilago palatina 

 thus Supports this canal laterally and behind. This appears alsa 

 from the figures of Gaupp, referred to above. 



The organ of Jacobson originates independently of the canal, 

 but Seydel is of opinion that the canal is not formed independently 

 of the organ. 



Also in other mammals traces of the cartilago palatina are ta 

 be found. In bis paper on Macroscelides proboscideus Broom 1 has 

 figured a cartilage on the outer side of the naso-palatine canal, 

 situated in the same way as in Tupaja. The author does not 

 mention it in the text, but designates it in the rlgure as a »small 

 isolated cartilage — possibly a rudimentary Stenson's cartilage 

 (not indicated in the adult)«. Though this is all the Information 

 he gives about it, I think it is no doubt to be regarded as homo- 

 logous with the above described cartilago palatina in Tupaja. 



There is no sickle-shaped cartilago ductus naso-palatini present 

 in Macroscelides proboscideus. 



The same author has observed in the foetal Lepus cuniculus* 

 a small cartilage which, according to the description given by him, 

 seems to agree strikingly with the cartilago palatina in Tupaja. 

 He supposes it to be homologous with the outer nasal floor cartilage 

 of the Monotremes, i. e. the cartilago palatina of Gaupp. 



No sickle-shaped cartilago ductus naso-palatini is present in 

 Lepus cuniculus. 



i R. Broom 1902 1. c. pl. 21, Fig. 7 i.e. 

 2 R. Broom 1898 1. c. 



