Case of "leo" in Judges 14:5

Question

Judges 14:5 in the Vulgata reads:

Descendit itaque Samson cum patre suo et matre in Thamnatha. Cumque venissent ad vineas oppidi, apparuit catulus leonis saevus, et rugiens, et occurrit ei.

I don't under the declension of leo above (genitive, leonis). The young lion appeared to Samson, so why is it not in accusative case? Or is the above actually saying something like "a young animal of lion [type] appeared [to Samson]"?

Contrast the above verse with other uses of leo in the same chapter, using the "correct" case:

• Accusative in Judges 14:6

  Irruit autem spiritus Domini in Samson, et dilaceravit leonem, quasi haedum in frustra discerpens, nihil omnino habens in manu : et hoc patri et matri noluit indicare

• Genitive in Judges 14:8

  Et post aliquot dies revertens ut acciperet eam, declinavit ut videret cadaver leonis, et ecce examen apum in ore leonis erat ac favus mellis.

Answer 1

Leonis is in the genitive case and paired with catulus (= "young of an animal" or "whelp"). Catulus leonis simply means "the whelp of a lion", i.e. a lion kitten.

Lucretius uses a similar construction in the plural:

at catuli pantherarum scymnique leonum
unguibus ac pedibus iam tum morsuque repugnant,
vix etiam cum sunt dentes unguesque creati. (De Rerum Natura 5.1036-38.)

Catulus is the subject of apparuit and thus is in the nominative case. The last sentence translates as follows:

When they came to the vineyards of the city, a fierce, raging young lion appeared and went to meet him [i.e. Samson].

Answer 2

Your supposition is correct:

Or is the above actually saying something like "a young animal of lion [type] appeared [to Samson]"?

The subject is catulus as indicated by its being in the nominative, and it is of the type leonis in the genitive.