In
nematodes, spicules, also known as copulatory spicules, are needle-like mating structures found only in males.
Male nematodes may have one or two spicules which serve to open the vulva of females and facilitate the transmission of
sperm, although sperm is not transferred directly by or through the spicules.
[Chitwood, B. G. & Chitwood, M. B. (1950). Introduction to Nematology (Vol. 1). Baltimore: Monumental Printing Co. (Function of spicule: pages 123-124)] The
gubernaculum
The paired gubernacula (from Ancient Greek κυβερνάω = pilot, steer) also called the caudal genital ligament, are embryonic structures which begin as undifferentiated mesenchyme attaching to the caudal end of the gonads (testes in males ...
is another organ of the nematode male copulatory system which guides the spicules during copulation.
References
Nematode anatomy
Animal male reproductive system
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