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THE EXTERNAL CHARACTERS OF POUCH EMBRYOS OF MARSUPIALS. 

 No. 7— MYRMECOBIUS FASCIATUS. 



By F. Wood Jones, D.Sc, F.Z.S., 

 Professor of Anatomy in the University of Adelaide. 



[Read August 9, 1923.] 



The "Nunibat" (Myrmecobius) .is, at the present time, one of the rarest 

 marsupials, and is an animal which is particularly difficult to obtain in any stage. 

 I am, therefore, fortunate in being able to examine five young examples in a good 

 state of preservation. One of these, which measures 23 mm. R.V. measurement, 

 I have been permitted to examine owing to the kindness of the authorities at 

 the Perth Museum. The other four, which are of an approximate length of 



Fig. 1. 



Myrmecobius fasciatus. 



Hair tracts of embryo 75 mm. maximum H.B. length. 



45 mm. R.V. measurement, and a maximum head and body length (measured 

 along the curve of the back) of 75 mm., were collected along with the mother 

 in Western Australia. These four, more advanced, young were clinging to 

 the elongated nipples of the mother, and were thus suspended without receiving 

 any protection whatever, save that may be afforded to their heads by the hispid 

 hair of the mother's ventral surface. Although these four young animals are 

 so relatively large and far advanced, their lip margins are still fused over the 

 greater portion of their extent; and it is evident that their liberation from the 

 nipples was not soon about to take place. 



The young are very remarkable in their general appearance, and by far 

 their most outstanding feature is the curious shortening of the muscle, which 



