139 



there being, not a narrow labial prolongation, or a mere philtrum, but a broad 

 area of the mesial nasal process in the middle third of the upper lip. (See fig. 4.) 

 The external ear. — In all stages examined the auricle is directed backwards. 

 The actual development of the various auricular processes is exceedingly inter- 

 esting. The mandibular portion of the auricle is at first prominent, and appears 

 as a ridge, which is lobed and folded in its inferior extremity. In the lower 

 portion of this ridge there seems to be at the 15 mm. stage the rudiments of a 

 tragus and a tragus pocket ; but with increasing growth the mandibular processes 



Fig. 5. 



Dasycercus cristicauda. 



Three stages in the development of the auricle. 



A, a IS mm. R.V. embryo. ; B, a 25 mm. R.V. embryo ; C, a young adult. 



become flattened and riband-like, and finally appear as a tortuous sculpturing 

 upon the pre-auricula region. The hyoid processes are at first three in number, 

 of which the middle one is by far the most prominent. The middle process of 

 the antihelix becomes progressively elevated and flattened from side to side, 

 and ultimately appears as the almost leaf-like processes antihelicis of the adult. 

 (See fig. 5.) 



Manus. — The digital formula of the 25 mm. young is3>4>2>5>l; a 

 formula which is also typical of the adult. The digits are fusiform, tapering 

 towards the tips, and no apical pads are obvious. The whole of the palm is 



