40a. German Philosopher, founder of communist theory with Marx? (-n-e--)
41a. Type of crossword clude, like this one for instance? (a-----)
21d. Wooded regions in the tropics characterised by heavy precipitation? (r-i-u-r-s--)
24d. Old Red Sandstone fossil fish with bone-like scales? (-s-e-l-p--)
35d. Southern region of Babylonia? (s-m-ss)