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On the Ultrastructure of the Mature Spermatozoon of a Chaetognath, Spadella cephaloptera
Author(s) -
Deurs Bo
Publication year - 1972
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1972.tb00576.x
Subject(s) - spermatozoon , spermatid , biology , ultrastructure , anatomy , sperm , flagellum , nucleus , microbiology and biotechnology , paleontology , botany , bacteria
The mature spermatozoon of Spadella cephaloptera belongs to the filiform type. At the front end it contains a membraneous cap, which may be an acrosomal structure, and some beaded sacs. A crystal structure is found in these sacs in spermatid stages. Near this front end there is a centriolar structure. A very elongated mitochondrial derivative runs through most of the sperm. In the central half of the sperm there is a structure composed of some longitudinal sacs lying alongside the axonema. The nucleus is situated in the hind end, just in front of a free flagellum. The spermatozoon is highly unique, but to some extent it agrees with spermatozoa found among arthropodes and gastropodes.