How would you explain this sentence?
Today begins the year of all suffering at the School of Cretins, Deaf-Mutes, and Boys of Bad Character on Avenida Puig. The classroom is like a prison hall full of writhing convicts, its iron-barred windows set high along one wall. Small boys and monkeys for pupils. No one else there could be fourteen or anything near it, they’re the size of baboons. The Holy Virgin feels very sorry but remains outside, on her cement pedestal in the small tidy garden. She has sent her son Jesus in with the other wretches, and he can’t flee either. He is pegged to his cross on the wall, dying all the day, rolling his eyes behind the back of Señora Bartolome, even He can’t stand the look of her clay-pipe legs and those shoes.
How would you explain this sentence: Small boys and monkeys for pupils?