public async Task <IPaginatedMessage> BuildTaxonMessageAsync(ITaxon taxon)
        {
            if (!taxon.IsValid())
            {
                return(null);
            }

            List <string> subItems = new List <string>();

            if (taxon.Rank.Type == TaxonRankType.Species)
            {
                ISpecies species = await Db.GetSpeciesAsync(taxon.Id);

                return(await BuildSpeciesMessageAsync(species));
            }
            else if (taxon.Rank.Type == TaxonRankType.Genus)
            {
                // For genera, get all species underneath it.
                // This will let us check if the species is extinct, and cross it out if that's the case.

                List <ISpecies> speciesList = new List <ISpecies>();

                foreach (ITaxon subtaxon in await Db.GetSubtaxaAsync(taxon))
                {
                    speciesList.Add(await Db.GetSpeciesAsync(subtaxon.Id));
                }

                speciesList.Sort((lhs, rhs) => TaxonFormatter.GetString(lhs, false).CompareTo(TaxonFormatter.GetString(rhs, false)));

                foreach (ISpecies species in speciesList.Where(s => s.IsValid()))
                {
                    subItems.Add(TaxonFormatter.GetString(species));
                }
            }
            else
            {
                // Get all subtaxa under this taxon.

                IEnumerable <ITaxon> subtaxa = await Db.GetSubtaxaAsync(taxon);

                // Add all subtaxa to the list.

                foreach (ITaxon subtaxon in subtaxa)
                {
                    if (subtaxon.Rank.Type == TaxonRankType.Species)
                    {
                        // Do not attempt to count sub-taxa for species.

                        subItems.Add(subtaxon.GetName());
                    }
                    else
                    {
                        // Count the number of species under this taxon.
                        // Taxa with no species under them will not be displayed.

                        long speciesCount = await Db.GetSpeciesCountAsync(subtaxon);

                        if (speciesCount > 0)
                        {
                            // Count the sub-taxa under this taxon.

                            long subtaxaCount = (await Db.GetSubtaxaAsync(subtaxon)).Count();

                            // Add the taxon to the list.

                            if (subtaxaCount > 0)
                            {
                                subItems.Add(string.Format("{0} ({1})", subtaxon.GetName(), subtaxaCount));
                            }
                        }
                    }
                }
            }

            // Generate embed pages.

            string title        = taxon.CommonNames.Count() <= 0 ? taxon.GetName() : string.Format("{0} ({1})", taxon.GetName(), taxon.GetCommonName());
            string fieldTitle   = string.Format("{0} in this {1} ({2}):", taxon.GetChildRank().GetName(true).ToTitle(), taxon.GetRank().GetName().ToLowerInvariant(), subItems.Count());
            string thumbnailUrl = taxon.GetPictureUrl();

            StringBuilder description = new StringBuilder();

            description.AppendLine(taxon.GetDescriptionOrDefault());

            if (subItems.Count() <= 0)
            {
                description.AppendLine();
                description.AppendLine(string.Format("This {0} contains no {1}.", taxon.GetRank().GetName(), taxon.GetChildRank().GetName(true)));
            }

            List <Discord.Messaging.IEmbed> pages = new List <Discord.Messaging.IEmbed>(EmbedUtilities.CreateEmbedPages(fieldTitle, subItems, options: EmbedPaginationOptions.AddPageNumbers));

            if (!pages.Any())
            {
                pages.Add(new Discord.Messaging.Embed());
            }

            IPaginatedMessage paginatedMessage = new PaginatedMessage(pages);

            foreach (Discord.Messaging.IEmbed page in paginatedMessage.Select(m => m.Embed))
            {
                page.Title        = title;
                page.ThumbnailUrl = thumbnailUrl;
                page.Description  = description.ToString();

                if (subItems.Count() > 0 && taxon.GetRank() != TaxonRankType.Genus)
                {
                    page.Footer += string.Format(" — Empty {0} are not listed.", taxon.GetChildRank().GetName(true));
                }
            }

            return(paginatedMessage);
        }