BILATERAL, PERIVULVAR CUTICULAR PORES IN TRICHOSTRONGYLID NEMATODES

A new hypodermal gland was discovered in female nematodes of the famil y Trichostrongylidae. Because the new structure appears to be associat ed with the vulva, it was named the perivulval pore. It is similar, ba sed on light and scanning electron microscopy, to phasmids that are lo cated laterally on the tails of nematodes of the class Secernentea. Li ke phasmids, perivulval pores are paired and bilateral, with cuticular ducts to the surface in the areas of the lateral chords. They are loc ated slightly posterior to the vulva in Haemonchus contortus, Haemonch us placei, Haemonchus similis, Mecistocirrus digitatus, Mazamastrongyl us pursglovei, Ostertagia ostertagi, and Cooperia oncophora, but in Tr ichostrongylus colubriformis they are slightly anterior to the vulva. Because of the location near the vulva and the similarity in structure to phasmids, which are, at least in part, secretory, the perivulval p ores should be considered as a possible source of a female attractant for males.