What does carapāx mean in Latin?

carapāx, a noun, means “carapace”.

What is the genitive of carapāx?

The genitive singular is carapācis. carapāx is masculine, third declension.

In classical Latin, [ˈka.ra.paːks]; in ecclesiastical (church) Latin, [ˈkaː.ra.paks].

noun · masculinethird declension

carapāx m or f (genitive carapācis)

Classical[ˈka.ra.paːks]Ecclesiastical[ˈkaː.ra.paks]

carapace
Planum carapacis ante et circa tuber oculorum longis et robustus dentibus armatum, margo frontalis curvatus, septem dentibus sulbverticalibus^([sic]) instructus.The plane of the carapace in front of and around the eye tubercle is armed with long and robust teeth, the frontal margin is curved, furnished with seven subvertical teeth.1946, Vladimir Šilhavý, “Nový rod a druh sekáčů, Odontosoma centetes, nov. gen., nov. spec. (Opiliones, subfamilia Phalangiinae)”, in Sborník Přírodovëdeckého klubu v Třebíči za rok 1939-1944. (overall work in Czech and Latin), Třebíč, page 56 of 55-57:
Multiplicatio zoosporis, quae ad carapaces Daphniarum assident.Multiplication of zoospores, which are attached to the carapaces of Daphnias.1973 March 31, Bohuslav Fott, “Protoderma daphnicola sp. nov. (Ulotrichales, Chlorophyceae), a New Epibiontic Alga Growing on Daphnia”, in British Phycological Journal, volume 8, number 1 (overall work in English and Latin), →DOI, page 39 of 39-41: