204 Report S.A.A. Advancement of Science. 



be considered as well worthy of specific rank, as no closely transi- 

 tional forms are yet forthcoming. The individual characters are 

 related to those of others, but the combinations are very distinct. 

 Individually, the two types are widely separated, both geographically 

 and by the stages reached in the transformation of their separate 

 characters. Efforts are being made to secure specimens from 

 districts intermediate between those whence ociilifera and geomeirica 

 have been obtained, and the areas occupied by their nearest allies ; 

 such specimens may possibly be transitional in character, and, accord- 

 ing to the conception here followed, this would affect the specific 

 standing of the two species. Stranchi I regard as a geomeirica in 

 which the nuchal has disappeared. 



Tentoria and verreauxii present very fluctuating characters, 

 especially dependent upon the locality from which they are obtained. 

 The members of the tentoria type pass by such gradual transitions 

 into those of the verreauxii type that it becomes impossible to say 

 where one species ends and the other begins. When studying the 

 extremes there is no difficulty in according them specific rank, but 

 in passing to the border forms no distinction can be maintained ; 

 geographically, they also pass into one another. Verreauxii can only 

 be regarded as a variety of the older tentoria. 



Trimeni seems to have fairly constant, generalized characters, 

 but these are so closely transitional with those of tentoria and 

 verreauxii that it cannot be considered as having attained specific 

 separation. It may be regarded as a variety of teyitoria. 



Smithii, fiskii, seimundi, and boettgeri unquestionably are not 

 sufficiently differentiated from the verreauxii sub-group to warrant 

 their recognition as distinct species. The combination of characters 

 emploj'ed to distinguish each one is such as may be found among a 

 large collection of verreaiixii from any one district. They do not 

 seem to indicate the formation of any new type, and, distinct from 

 verreauxii, cannot be accorded even varietal rank. 



For the time being, we may accord separate specific rank to 

 oculifera and geometrica, the transitional forms between them and 

 others have either disappeared or are not yet forthcoming ; all the 

 others, with the exception of strauchi, must be merged in tentoria 

 with the following varieties or sub-species : tentoria (sensu strictu), 

 ■verreauxii, and trimeni. 



b. Geographical Distribution. 



The different members of the geometrica-group appear to have 

 a very well-defined distribution over South Africa. 



Tentoria occurs along the southern and eastern coasts, extending 

 inland for a considerable distance. It reaches at least as far as 

 the Hex River Valley in its western extension, and to Natal in the 

 north-eastern direction. It varies very little near the coast, the 

 strongly knobbed type predominating ; more inland the shields are 

 usuallv flatter, the vellow rays more dominant at the angles, and the 

 femoral spines better developed. Towards Beaufort West it passes 

 insensibly into verreauxii, and towards the Hex River into trimeni. 



