354 



THE NECK GLANDS OF THE MARSUPIALIA. 



By James Johnstone, B.Sc. 



[Read May 10th, 1901.] 



The following notes are a description of the relation- 

 ships of the glands of the neck — 'the thymus organs, the 

 thyroid, the submaxillary and parotid glands, in two 

 marsupials, Dendrolagus and Acrobates. They are of 

 interest in view of the discovery by Symington,* in 1898, 

 of a superficial cervical thymus gland in many of these 

 animals, an organ which so far as is known is not found 

 in any other group of mammalia. It would appear from 

 the forms already studied that this superficial thymus 

 organ is characteristic of Dipro'todon't Marsupials, and 

 indeed affords an additional distinction between these and 

 the Polyprotodont families, and it seems very desirable, 

 both on this account, and in view of the remarkable con- 

 stancy in the relations of the thymus in other mammals, 

 that as many genera as may be available should be 

 described with this in mind. As a general rule little 

 attention has been paid in most descriptions of the 

 anatomy of Marsupials to the topography of the glands of 

 the neck, and the presence of this remarkable thymus 

 lobe has long been overlooked. 



I am indebted to Mr. H. C. Robinson, Assistant in the 

 Zoological Department, University College, Liverpool, for 

 these two animals, which were collected for him. The 

 Dendrolagus was a young male, measuring 31 cm. from 

 the snout along the back to the root of the tail. It was 

 either D. lumholtzi or D. bennetti, but I am unable to 



* The Thymus Gland in the Marsupialia. Journ. Anat. and 

 Physiology, vol. xii. (N.S.), 1898, pp, 278-291. 



