Synthetic Types 77 



America, Chili, Tropical Africa, South Africa, 

 Tibet, Indo-Malay, Australasia, and New Britain. 

 They are cryptozoic defenceless animals, shy and 

 nocturnal, hiding in damp places under leaves and 

 among rotting wood. They feed on small insects, 

 which they catch by the ejection of slime from little 

 papilla-like appendages in the mouth. They are vi- 

 viparous, and the newly born young one is already a 

 miniature of the parent. There is a long ante-natal 

 period, somewhat over a year in the case of Peripatus 

 capensis from South Africa. This helps to reduce the 

 chances of death. 



But we are taking Peripatus and its allies to illus- 

 trate what is meant by a "synthetic type." Peripatus 

 is like a ringed worm or Annelid in having numerous 

 regularly arranged kidney-tubes or nephridia, which 

 never occur in insect-like types. It has air-tubes or 

 tracheae, like simple forms of those by which Centi- 

 pedes and Insects breathe, but there is never any- 

 thing of this sort in worms. It has a body-wall muscu- 

 lature like that of worms, stump-like legs, and simple 

 eyes ; on the other hand, in having two pairs of ap- 

 pendages in the service of the mouth, in its heart and 

 circulation, in its salivary glands, and in its feelers, 

 it resembles an insect. The point is that Peripatus 

 and its relatives have many Annelid characteristics 

 and many Insect characteristics, and while they are 

 not to be regarded as the actual connecting links be- 

 tween segmented worms and air-breathing jointed- 

 footed animals, there can be little doubt that the 

 ancestors of insects passed through a grade of or- 



