The alpha-taxonomy of triphorids is still largely based on the study of the shell, and the scarcity of studies dealing with their anatomy is a result of the difficulty of sampling live animals and their very small size. Whereas radula and operculum are important structures in the taxonomy at the generic level, the jaw of triphorids has never been properly studied, being regarded as presenting a morphological homogeneity. The present research explored the basic anatomy (especially internal hard structures: operculum, jaw and radula) of 12 species from Brazil, distributed in 11 genera: Cheirodonta Marshall, 1983 (with a new generic allocation, Cheirodonta dupliniana (Olsson, 1916) comb. nov.), Cosmotriphora Olsson & Harbison, 1953, Iniforis Jousseaume, 1884, Latitriphora Marshall, 1983, Metaxia Monterosato, 1884, Monophorus Grillo, 1877, Nanaphora Laseron, 1958, Nototriphora Marshall, 1983, Sagenotriphora Marshall, 1983, Similiphora Bouchet, 1985 and Strobiligera Dall, 1924; in addition, the basic anatomy of the Caribbean species “Inella” harryleei Rolán & Fernández-Garcés, 2008 was analysed. Radular examination showed that the majority of species studied is properly allocated in their genera after comparisons in the literature with respective type species, albeit a few species are clearly in need of a new generic allocation. The jaw of triphorids is remarkably heterogeneous, displaying different patterns of scales and micro-pores between outer and inner sides.