| observations of the sheath extension of the third stage, infective larvae of trichostrongylus rugatus. | the length of the sheath extension of third stage (l(3)), infective larvae of trichostrongylus rugatus is reported. the total length and length of the sheath extension of l(3) recovered from the faeces of sheep originating from two localities in south australia were measured. the total length of larvae was 615-722 microm and the length of the sheath extension was 46-56 microm (mean 51.5). the larvae of t. rugatus comprised up to 72% of the larvae recovered. worm free sheep were infected with lar ... | 2004 | 15567044 |