Volume 40, Issue 3
September 1954, pages 69-88
pp 69-88 September 1954
It has been confirmed that the life-history ofTrichuris ovis is simple and direct and no migration of the larvæ takes place in the body of the host and no intermediate host is involved in the process.
Segmentation of egg under laboratory conditions has been described upto the formation of the embryo or the first stage larva.
The various stages of larval development, from the first to the fourth stage have been studied.
The first stage larva is characterised by the presence of an oral spear and a double row of cells in the cell body. The approximate ratio of œsophagus and intestine is 7: 1. In later stages, the oral spear is lost and the cell body consists of a single row of cells, with prominent nuclei.
In the second stage larva, the ratio of œsophagus and intestine is reduced to 6:1, though sometimes it is slightly greater.
The third stage larva shows the presence of genital rudiments and the ratio of the œsophagus and the intestine becomes 5:1.
In the fourth stage larva, the sexes can be differentiated and in its later stages, almost all the sexual organs can be distinguished. The ratio of œsophagus and intestine becomes 3:1.