Siphon-like tubes/glands present on the dorsal disc with the apical tip usually flanged or inflated, either numerous and distributed (in Siphoninus) or numbering a few submedian pairs ( in Asiothrixus antidesmae).
The siphon-like tubular structures in Siphoninus and Asiothrixus antidesmae Takahashi may be considered by some as homologous structures similar to the robust acute or blunt spines. The Siphon-like tubes/glands should not be confused with robust dorsal disc setae
Asiothrixus antidesmae Takahashi
Siphoninus siphon-like tubes/glands