SQL & PL/SQL :: Table Is Missing In User_segments Data Dictionary Table

In my database I found some anomalies like

SQL> select SEGMENT_NAME, SEGMENT_TYPE, BLOCKS, EXTENTS, BYTES/1024
2 from user_segments
3 where SEGMENT_TYPE='TABLE'
4 ORDER BY SEGMENT_NAMe;
[code]....

The countries table is missing in user_segments data dictionary view.But I can queries the countries using select statement.

SQL> SELECT * FROM COUNTRIES;

CO COUNTRY_NAME REGION_ID
-- ---------------------------------------- ----------
AR Argentina 2
AU Australia 3
BE Belgium 1
BR Brazil 2
[code]...

why the country table is missing in user_segments data dictionary table.