lf)4 



M 



R. R. COLLETT ON ECHIDNA ACANTHION. [Feb. 3 



In a male specimen, with a total length of 448 millim., the skeleton 

 is perfectly ossified. 



The sl'itU is very much like that of E. aculeata, but may probably 

 always be distinguished by its narrower cerebral area and propor- 



Fig. 1. 



Skull of Echidna acanthion, cJ. No. 5. 



tionally short snout, aUhoup;h scarcely different in this respect fronn 

 the South-Australian and Tasmanian species. The length of the 

 skull in proportion to the total length of tlie skeleton is as 1 to 4 

 (3-93 to 4-2G). 



When the sknll is seen from behind, the lateral profile, especially 

 in the somewhat younger specimens, widens regularly downwards, 

 the OS sqvamosvm having its greatest height below, and the upper 

 part of OS iemporale {perioiiciim) diminishes regularly towards the 

 jjarietalia. The greatest breadth, which is to tlie length as 1 to 2o, 



Fig. 2. 



Skull of Echidna acanthion, J . No. 9. 



is therefore in JE. acanthion situated at the bottom of the skull, 

 quite near the glenoid fossa. 



In the perfectly full-grown specimens (male and female) the skull 

 becomes less narrow upwards, but in all cases does not widen as in 



