Different types of oesophagus of nematode

Different types of oesophagus:

1.Rhabditiform: They have a club shaped anterior portion connected by a narrow neck with a pear shaped posteror bulb. It is found in 1^st stage larvae/pre parasitic larvae & non parasitic larvae/free living genera of rhabditida nematodes, e.g pre-infective stage of strongyles

2.Filariform:It is a simple oesophagus .It is also club shaped without posteror bulb. Found in the 2^nd & later stage larvae & parasite genera of the bursate nematodes –Rhabditida

   e.g Adult strongyles

3.Bulb shaped oesophagus: with a large posterior swelling /bulb, e.g Ascaridoids

4.Double bulb shaped oesophagus :e.g Oxyuroids

5.Muscular glandular: The oesophagus which is muscular anteriorly and  posterior part being glandular, e.g, Spiruroids , Filarioids

6.Capillary form: Passing through a single column of cells, the whole being known as stichosome .e.g, Trichurioid