The adults vary in length from 8 to 75 centimetres (3 to 30 inches) with the exception of Thomson's caecilian (Caecilia thompsoni), which can reach .
ðɪ ɐdˈʌlts vˈɛɹi ɪn lˈɛŋθ fɹʌm ˈeɪt tə sˈɛvənti fˈaɪv sˈɛntɪmˌiːɾɚz θɹˈiː tə θˈɜːɾi ˈɪntʃᵻz wɪððɪ ɛksˈɛpʃən ʌv tˈɑːmsənz kiːsˈɪliən kiːsˈɪliə təmpsˈoʊni, wˌɪtʃ kæn ɹˈiːtʃ .