An African professor - Core Course

An African professor went back home.He was late 4 d ferry and he took a boat. The following happened between them

Professor: "do u know PSYCHOLOGY, GEOLOGY and CRIMINOLOGY"
Boat-man: "no"
Professor: "Hah, u don't know nothing"

Then suddenly boat started sinking...

Boat-man ask prof: "do u know SWIMMOLOGY and to ESCAPALOGY away 4rm CROCOLOGY"
Professor: "no"
Boat-man: "Well today u will DROWNOLOGY and become a chapter in the GRAVEOLGY books"
Professor: "Now i know i've missed a Core Course in my Studying days"