a. At the end of words s, being only feebly sounded, does not make position with a following consonant; it sometimes disappeared altogether. This usage continued in all poets till Cicero's time (§ 15. 7).
b. A long syllable immediately preceded or followed by the ictus may be shortened (iambic shortening): -
c. In a few isolated words position is often disregarded.[3][Scholars are not yet agreed upon the principle or the extent of this irregularity.] Such are ille, immo, inde, iste, omnis, nempe, quippe, unde.
d. The original long quantity of some final syllables is retained.
1. The ending -or is retained long in nouns with long stem-vowel (original r-stems or original s-stems): -
2. The termination -es (-itis) is sometimes retained long, as in mílés, superstés.
3. All verb-endings in -r, -s, and -t may be retained long where the vowel is elsewhere long in inflection: -
e. Hiatus (§ 612. g) is allowed somewhat freely, especially at a pause in the sense, or when there is a change of speaker.[4][The extent of this license is still a question among scholars; but in the present state of texts it must sometimes be allowed.]