 Several more species were named around 1900 , including Nycticebus menagensis ( originally Lemur menagensis ) by Richard Lydekker in 1893 and Nycticebus pygmaeus by John James Lewis Bonhote in 1907 . However , in 1939 Reginald Innes Pocock consolidated all slow lorises into a single species , N. coucang , and in his influential 1953 book Primates : Comparative Anatomy and Taxonomy , primatologist William Charles Osman Hill also followed this course . In 1971 Colin Groves recognized the pygmy slow loris ( N. pygmaeus ) as a separate species , and divided N. coucang into four subspecies , while in 2001 Groves opined there were three species ( N. coucang , N. pygmaeus , and N. bengalensis ) , and that N. coucang had three subspecies ( Nycticebus coucang coucang , N. c. menagensis , and N. c. javanicus ) . 
