2o8 Report S.A.A. Advancement of Science. 



fassu with one another (correlated variation). In the former the 

 individuals possess extreme and transitional stages or transitional 

 stages of different degrees, in the latter they are either all extreme 

 or all transitional stages. 



7. Each varietal type has a restricted geographical distribution, 

 without overlapping, and the more nearly related types occupy 

 adjacent areas. Compared with other South African tortoises, it is 

 found that each species of the genus Homopus has a restricted distri- 

 bution, with characters showing little variation, while T. fardalis 

 and T. angulata are widely distributed, also with slight variability. 



8. Among the ten described species of the geometric^-^xow^, 

 only three distinct types of combination are recognizable : oculifera, 

 geometrica, and tentoria. These may for the present be considered as 

 sufficiently separated from any transitional forms to be given specific 

 rank, and tentoria presents at least three well marked varieties or 

 sub-species : tentoria (sensu strictti), verreauxii, and trimeni. Four 

 of the other described species (smithii, flskii, seimiirtdi, boettgeri) are 

 not sufficiently distinct from the fluctuations of tentoria to warrant 

 even varietal recognition, while strauchi may be a variety of 

 geometrica. 



