diff --git a/src/reader.rs b/src/reader.rs
index b7203ba4..d2b979f0 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -29,7 +29,7 @@ impl<T: Reader+Seek> ZipReader<T>
     {
         let footer = try!(spec::CentralDirectoryEnd::find_and_parse(&mut reader));
 
-        if footer.number_of_disks > 1 { return unsupported_zip_error("Support for multi-disk files is not implemented") }
+        if footer.disk_number != footer.disk_with_central_directory { return unsupported_zip_error("Support for multi-disk files is not implemented") }
 
         let directory_start = footer.central_directory_offset as i64;
         let number_of_files = footer.number_of_files_on_this_disk as uint;
diff --git a/src/spec.rs b/src/spec.rs
index 622641d7..76155c5d 100644
--- a/src/spec.rs
+++ b/src/spec.rs
@@ -97,7 +97,7 @@ pub fn write_local_file_header<T: Writer>(writer: &mut T, file: &ZipFile) -> IoR
 
 pub struct CentralDirectoryEnd
 {
-    pub number_of_disks: u16,
+    pub disk_number: u16,
     pub disk_with_central_directory: u16,
     pub number_of_files_on_this_disk: u16,
     pub number_of_files: u16,
@@ -118,7 +118,7 @@ impl CentralDirectoryEnd
                 desc: "Invalid digital signature header",
                 detail: None })
         }
-        let number_of_disks = try!(reader.read_le_u16());
+        let disk_number = try!(reader.read_le_u16());
         let disk_with_central_directory = try!(reader.read_le_u16());
         let number_of_files_on_this_disk = try!(reader.read_le_u16());
         let number_of_files = try!(reader.read_le_u16());
@@ -129,7 +129,7 @@ impl CentralDirectoryEnd
 
         Ok(CentralDirectoryEnd
            {
-               number_of_disks: number_of_disks,
+               disk_number: disk_number,
                disk_with_central_directory: disk_with_central_directory,
                number_of_files_on_this_disk: number_of_files_on_this_disk,
                number_of_files: number_of_files,