The approximate locations of the rRNA and protein-encoding genes were determined by aligning each unannotated genome with genes from other caenogastropod mt genomes. The precise boundaries of rRNA genes could not be determined due to the lack of sequence similarity at the 5' and 3' ends; therefore, the location of each rRNA gene was assumed to extend from the boundary of the upstream flanking gene to the boundary of the downstream flanking gene, as in [41]. A standard initiation codon was located at the beginning of each protein-encoding gene (either ATG, ATA, or GTG), and the derived amino acid sequence was aligned with homologous protein sequences to ensure that this was a suitable initiation codon (based on length). When possible, the first proper stop codon (TAG or TAA) downstream of the initiation codon was chosen to terminate translation; however, to reduce overlap with downstream genes, abbreviated stop codons (T or TA) were selected for some genes. In these instances, polyadenylation of the mRNA was assumed to restore a full TAA stop codon [7]. Regardless, some genes appeared to overlap based on the conservation of their open reading frame sequences and the lack of a potential abbreviated stop codon. Gene locations and secondary structures of tRNAs were identified using tRNAscanSE [42] and ARWEN [43]. On the rare occasion that these programs did not find all of the expected tRNAs, the remaining tRNAs were found by eye and folded manually. We produced tRNA drawings manually using Canvas (ACD Systems). Using cox1 as the conventional starting point for the four genomes, linear maps of the circular genomes were created to facilitate comparison of gene orders amongst vermetids, across available caenogastropods, and between caenogastropods and other select molluscs, including the abalone, Haliotis rubra (Class Gastropoda,Superorder Vetigastropoda), the octopus, Octopus vulgaris (Class Cephalopoda), and the chiton, Katharina tunicata (Class Polyplacophora).