Ag-NOR and C-banding analysis of spermatocyte chromosomes ofClavelina lepadiformis(Ascidiacea, Aplousobranchiata)

SUMMARYChromosome number n = 9 and 2n = 18 for Clavelina lepadiformis (Ascidiacea, Aplousobranchiata) from the Gulf of Palermo have been determined. Silver staining analysis of testicular cells reveals that within-individual variability in NOR banding patterns is present. Using the C-banding procedure, a very impressive heterochromatin amount seems to characterize the chromosome set of this species.