Vol. X, No. 6.] I ndo- Australian Passalid Coleoptera. 209 



[N.S.] 



r position in which this species stands — at the top of the most 

 progressive line of evolution in its group — in the Passalidae. 



Evidently, then, the existence of this species in many 

 groups, both terrestrial and aquatic, to which Clark calls atten- 

 tion, is a fact which calls for further investigation, with a view 

 to determining in which cases it stands at the bottom, and 

 in which at the top of the evolutionary series of the group or 

 M genus " to which it belongs ; and whether it is ever situated 

 between the two. For this is bound to have a considerable 

 bearing on the interpretation of the geographical distribution 

 of that group. 



