Exceptions in us.
[2454.] u is long in the nominative singular of consonant stems with ū before the final stem consonant: as, tellūs, stem tellūr-; palūs, once palus (Hor.), stem palūd-; in the genitive singular and nominative and accusative plural of nouns with stems in -u-: as, frūctūs; and in the ending of some Greek names: as, N. Panthūs; G. Sapphūs.
Exceptions in as.
[2455.] Final as has short a in anas and in the ending of some Greek nouns: as, N. Īlias; Pl. Ac. cratēras.
Exceptions in es.
[2456.] Final es has short e in the nominative singular of stems in -d- and -t- which have the genitive in -idis, -itis, and -etis ([475], [476]): as, praeses, teges, comes (but ē in abiēs, ariēs, and pariēs), also, in penes, in compounds of es, thou art, and in the endings of some Greek nouns: as, N. Cynosarges; Pl. N. Arcades, cratēres.
Exceptions in os.
[2457.] Final os has short o in the nominative of stems in -o-: as, servos, suos, Dēlos; also in compos, impos, and exos; and in the endings of some Greek nouns: as, N. and Ac. epos; G. chlamydos, Erīnyos.
[Position.]
[2458.] For the general rule of position, see [177], [178]; but, except in the thesis of a foot, a final syllable ending with a short vowel generally remains short before a word beginning with two consonants or a double consonant: as, molliă strāta, nemorōsă Zacȳnthos, lūcĕ smaragdī.