Original: The braincase, being only 340 cm³ to 360 cm³ in volume is similar to that of extant chimpanzees and is notably less than the approximate human volume of 1350 cm³.
Simplified: The braincase is only 340 cm³ to 360 cm³ in volume, about the same as chimpanzees. It is much less than the human volume of about 1350 cm³.