SOURCE: Liber Primus, by Joseph Dana (1832) at GoogleBooks. For more information and other versions of this fable, see the links list for Perry 253.
READ OUT LOUD. Choose which marked text you prefer to practice with - macrons or accent marks - and read the text out loud until you feel comfortable and confident. Then, try reading the unmarked text at the bottom. It should be easy for you after practicing with the marked texts. :-)
MACRONS. Here is the text with macrons:
Canis, cum forte cōchleam offendisset, ōvum esse ratus, magnō ōris hiātū avidissimē eam dēvorāvit. Illīs autem graviter dolentibus, exclāmābat, "Ah! Meritās luō stultitiae poenās, quī omnia rotunda crēdidī esse ōva."
ACCENT MARKS. Here is the text with ecclesiastical accents, plus some color-coding for the words of three or more syllables (blue: penultimate stress; red: antepenultimate stress):
Canis, cum forte cóchleam offendísset, ovum esse ratus, magno oris hiátu avidíssime eam devorávit. Illis autem gráviter doléntibus, exclamábat, "Ah! Méritas luo stultítiae poenas, qui ómnia rotúnda crédidi esse ova."
UNMARKED TEXT. Here is the unmarked text - after practicing with the marked text that you prefer, you should not have any trouble with the unmarked text:
Canis,
cum forte cochleam offendisset,
ovum esse ratus,
magno oris hiatu
avidissime eam devoravit.
Illis autem graviter dolentibus,
exclamabat,
"Ah! Meritas luo stultitiae poenas,
qui omnia rotunda
credidi esse ova."
IMAGE. Here is an illustration for the story (image source), showing some white snails - do you think they look like eggs...?