352 



A. Ärnbäck Christie-Lincle 



such we may, no doubt, regard the cartilaginous bar which repre- 

 sents a rudimentary turbinal. The presence of a well developed 

 cartilago palatina as well as the absence of a sickle-shaped cartilage 

 may also probably be regarded as characterizing a low mammal. 



Special attention should be paid to the above-mentioned cul-de- 

 sacs. If they are to be regarded as primitive characters or not 

 may be an open question. 



It is not only in Tupaja that a complicated structure of the 

 organ of Jacobson is to be found. 



In a very young specimen of Gymnura rafflesii 1 — sex unknown 

 — the epithelium of the inner wall — the sensory epithelium — 



forms numerous longitudinal folds 

 Fig. 11. as is shown by Fig. 11. 



In another young individual 

 of the same species — a male — 

 the epithelium of the inner wall 

 is as usual many times thieker 

 than that of the outer wall, but 

 there are no longitudinal folds 

 at all. 



As to the cartilaginous parts 

 of Gymnura they are of no special 

 interest. 



Having also had the oppor- 

 tunity of examining microscopic 

 preparations of foetal specimens 

 of Erinaceus europaeus and Hy- 

 lomys suülus, I have not found 

 in this organ anything remark- 

 able or essentially dififering from what is typical in the Monodelphia. 

 But about the sex of the individuals examined I know nothing. 



Gymnura rafflesii. Juv. Transverse section of 



region of Jacobson's organ. c.ps. cartilago para- 



septalis; J.o. Jacobson's organ. x 60. 



As is well known, the organ of Jacobson in Omithofhynchus 

 is supported laterally by a well developed turbinal, which extends 

 to the front of the organ. A turbinal is also present in Echidna, 

 though it is highly reduced as compared with that of Ornitho- 



1 The microscopic preparations of Erinaceidae used in this examination 

 belong to the Zootomical Institute of the University in Stockholm. 



