title: Male chromosomes in two populations of Branchiostoma lanceolatum.
mesh_terms: D000818:Animals; D002816:Chordata, Nonvertebrate / Q000166:cytology*; D004739:England; D005828:Genetics, Population; D007558:Italy; D007621:Karyotyping; D008297:Male; D008858:Microscopy, Phase-Contrast; D012730:Sex Chromosomes