470 G among . — The Comparative Morphology of 
Mamillariae with a furrow, and these in turn by its dis- 
appearance to the smooth tubercled forms, and from these 
came finally the most specialized of all of the genera, Pelecy- 
phora. Returning to the Echinocacti, we find Melocactus 
as a later branch, and as earlier ones Leuchtenbergia and 
Anhalonium. The relations of the two latter are somewhat 
puzzling. Though the embryos of Anhalonium in some ways 
recall the Cephalocactus division of Echinocactus , yet the 
presence of two growing-points in each tubercle places it 
near Mamillaria and relates it to Thelocactus , and it has 
probably come off from the latter near to but independently 
of Mamillaria. As to Leuchtenbergia , the pointed cotyledons 
