diff --git a/src/initmpi.f90 b/src/initmpi.f90
index 5b5001e..7bea857 100644
--- a/src/initmpi.f90
+++ b/src/initmpi.f90
@@ -102,7 +102,7 @@ subroutine initmpi(my_block,nblocks,id_first,dims,cbc,bc,is_periodic,periods, &
     call MPI_BCAST(lo_g,3,MPI_INTEGER,0,comm_block)
     hi_g(:) = lo_g(:)+ng(:)-1
     !
-    ! determine size of the domain in the periodic direction
+    ! determine size of the domain in the periodic directions
     !
     call MPI_ALLREDUCE(lo_g(1),lo_g_min(1),3,MPI_INTEGER,MPI_MIN,MPI_COMM_WORLD)
     call MPI_ALLREDUCE(hi_g(1),hi_g_max(1),3,MPI_INTEGER,MPI_MAX,MPI_COMM_WORLD)
diff --git a/src/param.f90 b/src/param.f90
index 0c07533..27681dd 100644
--- a/src/param.f90
+++ b/src/param.f90
@@ -161,7 +161,7 @@ subroutine read_input()
     vol_all = product(lmax(:)-lmin(:))/product(dims(:))
     call mpi_allreduce(MPI_IN_PLACE,vol_all,1,MPI_REAL_RP,MPI_SUM,MPI_COMM_WORLD,ierr)
     !
-    ! determine length of the domain in the periodic direction
+    ! determine length of the domain in the periodic directions
     !
     call MPI_ALLREDUCE(lmin(1),lmin_min(1),3,MPI_REAL_RP,MPI_MIN,MPI_COMM_WORLD,ierr)
     call MPI_ALLREDUCE(lmax(1),lmax_max(1),3,MPI_REAL_RP,MPI_MAX,MPI_COMM_WORLD,ierr)