diff --git a/src/gc.c b/src/gc.c
index 4b45069e..1c8766b7 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -32,7 +32,7 @@
 int g_dump_filedes;
 
 #define M2_CELL_SIZE 1U
-// CONSTANT M2_CELL_SIZE 12
+// CONSTANT M2_CELL_SIZE 24
 
 char *
 cell_bytes (struct scm *x)
diff --git a/src/symbol.c b/src/symbol.c
index cd82328f..9acefaee 100644
--- a/src/symbol.c
+++ b/src/symbol.c
@@ -27,10 +27,10 @@
 
 #if __M2_PLANET__
 #define M2_CELL_SIZE 12
-// CONSTANT M2_CELL_SIZE 12
+// CONSTANT M2_CELL_SIZE 24
 #else
 #define M2_CELL_SIZE 1
-// CONSTANT M2_CELL_SIZE 12
+// CONSTANT M2_CELL_SIZE 24
 #endif
 
 struct scm *
diff --git a/src/test/gc.c b/src/test/gc.c
index 8d3c70cf..5de9f8ff 100644
--- a/src/test/gc.c
+++ b/src/test/gc.c
@@ -25,7 +25,7 @@
 #include <string.h>
 
 #define M2_CELL_SIZE 1
-// CONSTANT M2_CELL_SIZE 12
+// CONSTANT M2_CELL_SIZE 24
 
 int g_debug;
 
diff --git a/src/vector.c b/src/vector.c
index 0fc84040..84daef26 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -23,10 +23,10 @@
 
 #if __M2_PLANET__
 #define M2_CELL_SIZE 12
-// CONSTANT M2_CELL_SIZE 12
+// CONSTANT M2_CELL_SIZE 24
 #else
 #define M2_CELL_SIZE 1
-// CONSTANT M2_CELL_SIZE 12
+// CONSTANT M2_CELL_SIZE 24
 #endif
 
 struct scm *