A bit is shown for use in drilling earthen formations which includes a body having a bit face on one end and a shank on the opposite end which is connected in the drill string. The bit body has a tubular bore which communicates with an interior bore of the drill string for circulation of fluids. The bit face increases in external diameter between a nose and a gage region of the bit. A fluid opening communicates the bit face with the tubular bore for circulating fluid to the bit face. A plurality of fluid courses are disposed on the bit body, the fluid courses becoming ever wider and ever deeper along their entire disposition from their lowermost incorporation through the gage region thereof.