18: De leone et mure

The fable of the lion and the mouse is one of the most retold fables of the collection. The lion spares the mouse, and in turn, the mouse nibbles a net that has ensnared the lion. This moral states that even the smallest of creatures can be useful to the strongest. 

Perry 150

frigida ... silva: “a cold forest”;  nom. subject.

sopito ...  leoni: “soothes the sleeping lion”;  dat. after blanditur.

mure: “having been pressed (on) by the mouse”;  ablative of means. Note the polyptoton here and play of mus and murus. One gets the impression that the mouse is running all over the sleeping lion, and stepping on the lion. 

Ille precem lībrat: whereas the first ille was referring to the mouse who was praying, this ille refers to the lion, “that one (i.e. the lion) weighs the prayer.” Librat can mean “weigh” or “consider.”

precī: dative with supplicat, “humbles itself to the prayer.” 

tamen ante: ante shows the relationship between this clause and the previous clause, so take this as, “beforehand however.” 

haec: “he moves these things in his mind,” i.e. he ponders these things;  neut. pl. Acc.

quid laudis emēs: “what (of) praise will you win?”

mure perempto: “with (the) mouse having been killed”;  ablative absolute.

Summōs vincere parva pudet: “it is shameful that great ones should conquer small things.” Pudet sets up an indirect statement. Note the change in gender here between summos and parva. 

dignetur: pres. subj. in a future less vivid protasis (+ abl.).

leōnī: dative with dedecus. 

muri: dative with decus.  

vincat: “if (ever) he should conquer”;  pres. subj. in Future Less Vivid Subjunctive.

sīc vincere vincī est: “to conquer so is to be conquered”;  vinci is a pres. pass. inf. as pred.

Vincere crimen habet: “to conquer has a crime,” i.e. it is a crime to conquer.

sit ... sit…: “although it is…although it is…”;  pres. concessive subj. with infinitives as subjects.

minimo... ab hoste: “ from this very small enemy”;  abl.

minus: “would be less”;  pred.

de pretio vīctī: “on the value of the conquered.”

tantus erit  ... . quanta fuit: “will be as great ... as was”; correlatives.

grātēs: = gratias. 

si ... possit: “if he should be able”;  pres. subj. in future less vivid protasis (+ inf.).

reddere: supply opem.

spondet opem: future indicative in a future more vivid apodosis, making this a mixed condition. 

rete: “he goes under a net”;  abl. after subit.

prōdest: = potest, as in the next line too. 

viribus: “to use his strength”;  abl. after uti.

querulo murmure: “with a mournful roar”;  ablative of manner.

damna: direct object of loqui, “to tell (of) his injuries.” 

hunc reperit: “he meets him (i.e. the lion) again.”

loca: you could take this as plural for singular, or because the mouse is looking for specific weak places in the net. 

vincula: “ropes,” “cords.” 

hac ope: “by this help”;  ablative of means.

pēnsat opem: supply reddere. “He thinks that he (i.e. the mouse) repays (his - i.e. the lion’s) help.”  

Potuit: = potuit facere, “was able (to do).”

cui: lit., “to whom,” but works better as, “to him,” i.e. the mouse.

dans: “by giving”; pres. part., instrumental.

se ... ipse sibi : “He himself gave himself to himself,” i.e. he helped himself. The implication here is that by setting the mouse free, the lion set himself free. 

potes: “you who are capable of” + acc. 

potentem: “despises the one being capable of”;  pres. part. acc.

si quis ... nequit: “if anyone was unable to,” i.e. if anyone refrained from (+ inf.).