diff --git a/pdfannots/__init__.py b/pdfannots/__init__.py
index ff512f7..c9bafc0 100644
--- a/pdfannots/__init__.py
+++ b/pdfannots/__init__.py
@@ -62,9 +62,13 @@ def _mkannotation(
         # decode as string, normalise line endings, replace special characters
         contents = cleanup_text(pdfminer.utils.decode_text(contents))
 
-    coords = pdftypes.resolve1(pa.get('QuadPoints'))
+    # Rect defines the location of the annotation on the page
     rect = pdftypes.resolve1(pa.get('Rect'))
 
+    # QuadPoints are defined only for "markup" annotations (Highlight, Underline, StrikeOut,
+    # Squiggly), where they specify the quadrilaterals (boxes) covered by the annotation.
+    quadpoints = pdftypes.resolve1(pa.get('QuadPoints'))
+
     author = pdftypes.resolve1(pa.get('T'))
     if author is not None:
         author = pdfminer.utils.decode_text(author)
@@ -80,7 +84,7 @@ def _mkannotation(
         createds = pdfminer.utils.decode_text(createds)
         created = decode_datetime(createds)
 
-    return Annotation(page, annot_type, coords, rect,
+    return Annotation(page, annot_type, quadpoints, rect,
                       contents, author=author, created=created)
 
 
diff --git a/pdfannots/types.py b/pdfannots/types.py
index d641050..8bcfaf5 100644
--- a/pdfannots/types.py
+++ b/pdfannots/types.py
@@ -234,12 +234,20 @@ def update_pageseq(self, line: LTTextLine, pageseq: int) -> None:
 
 class AnnotationType(enum.Enum):
     """A supported PDF annotation type. Enumerant names match the Subtype names of the PDF spec."""
+
+    # A "sticky note" comment annotation.
     Text = enum.auto()
+
+    # Markup annotations that apply to one or more regions on the page.
     Highlight = enum.auto()
     Squiggly = enum.auto()
     StrikeOut = enum.auto()
     Underline = enum.auto()
 
+    # A single rectangle, that is abused by some Apple tools to render custom
+    # highlights. We do not attempt to capture the affected text.
+    Square = enum.auto()
+
 
 class Annotation(ObjectWithPos):
     """
@@ -268,19 +276,19 @@ def __init__(
             self,
             page: Page,
             subtype: AnnotationType,
-            coords: typing.Optional[typing.Sequence[float]] = None,
+            quadpoints: typing.Optional[typing.Sequence[float]] = None,
             rect: typing.Optional[BoxCoords] = None,
             contents: typing.Optional[str] = None,
             author: typing.Optional[str] = None,
             created: typing.Optional[datetime.datetime] = None):
 
-        # Construct boxes from coords
+        # Construct boxes from quadpoints
         boxes = []
-        if coords:
-            assert len(coords) % 8 == 0
-            while coords != []:
-                (x0, y0, x1, y1, x2, y2, x3, y3) = coords[:8]
-                coords = coords[8:]
+        if quadpoints is not None:
+            assert len(quadpoints) % 8 == 0
+            while quadpoints != []:
+                (x0, y0, x1, y1, x2, y2, x3, y3) = quadpoints[:8]
+                quadpoints = quadpoints[8:]
                 xvals = [x0, x1, x2, x3]
                 yvals = [y0, y1, y2, y3]
                 box = Box(min(xvals), min(yvals), max(xvals), max(yvals))
diff --git a/tests.py b/tests.py
index 7e018ee..4886cbd 100755
--- a/tests.py
+++ b/tests.py
@@ -133,6 +133,22 @@ def test(self) -> None:
         self.assertEqual(a.gettext(), 'This is a sample statement.')
 
 
+class Issue46(ExtractionTestBase):
+    filename = 'issue46.pdf'
+
+    def test(self) -> None:
+        self.assertEqual(len(self.annots), 3)
+
+        self.assertEqual(self.annots[0].subtype, AnnotationType.Highlight)
+        self.assertEqual(self.annots[0].gettext(), 'C – Curate')
+
+        self.assertEqual(self.annots[1].subtype, AnnotationType.Square)
+        self.assertEqual(self.annots[1].gettext(), None)
+
+        self.assertEqual(self.annots[2].subtype, AnnotationType.Highlight)
+        self.assertEqual(self.annots[2].gettext(), 'This was a novel idea at the time')
+
+
 class Pr24(ExtractionTestBase):
     filename = 'pr24.pdf'
 
diff --git a/tests/issue46.pdf b/tests/issue46.pdf
new file mode 100644
index 0000000..7f53e31
Binary files /dev/null and b/tests/issue46.pdf differ