The Highway Code Great Britain version, available in English and Welsh, applies to England, Scotland and Wales, but regional specific signs such as driver location signs in England or bilingual signs in Scotland and Wales are not covered. The Northern Ireland version, available in English and Irish, applies to Northern Ireland. Costing one penny, the first edition of the Highway Code was published on 14 April 1931. It contained just 18 pages of advice, including the arm signals to be given by drivers and police officers controlling traffic. The second edition, considerably expanded, appeared in 1934, and now illustrated road signs for the
Validly published name are sometimes in use. This may occur when a taxonomist finds and recognises a taxon and thinks of a name, but delays publishing it in an adequate manner. A common reason for this is that a taxonomist intends to write a "magnum opus" that provides an overview of the group, rather than a series of small papers. Another reason is that the code of nomenclature changes with time, and most changes have retroactive effect, which has resulted in some names that the author thought were validly published, becoming invalid. In zoology, the term valid name has a different meaning, equivalent