The spermatozoon of arthropoda. XXII. the 12 + 0’, ‘14 + 0’ or aflagellate sperm of protura

ABSTRACT The spermatozoa of three genera of Protura are unconventional. Two of them, Acerentulus and Acerentomon, display hitherto undescribed axoneme patterns: ‘12 + 0 ‘in the former, ‘14 + 0’ in the latter. All the doublets are devoid of arms. The third genus, Eosentomon has a disk-shaped spermatozoon, devoid of tail. The presence of such unusual patterns is related to the non-motility of the spermatozoa.