[jiang]

Dear teachers,
I found the following two sentences difficult to understand.

1. Within the primate order, humans are most closely related to the anthropoid apes ( the African chimpanzee and the gorilla and the Southeast Asian orang-utan and gibbon), and of these, to the chimpanzee and the gorilla.

The reason I feel puzzled is as follows:

According to the sentence ' the chimpanzee and the gorilla' are more general than anthropoid apes. That is, anthropoid apes are included in the chimpanzee and the gorilla.
But if the latter part 'and of these, to the chipanzee and the gorilla' could be rewritten as ' humans are most closely related to the chimpanzee and the gorilla' what 'does these' refer to? If it refers to 'anthropoid apes' that means 'the chimpanzee and the gorilla' should be included in anthropoid apes. So I think the two parts of the sentence contradicts with each other.

2. Childhood is longer, the closer the species is to humans.
I think the sentence belongs to 'the more/less.....the more/less' structure. So it should be 'The longer the childhood is, the closer the species is to humans.
I can't find the same structure in my grammar book. Why was it written this way? Is it also part of the structure?

I am looking forward to hearing from you.

Thank you in advance.

Jiang