ἐξ ὀνύχων λέοντα τεκμαίρεσθαι → judge by the claws, judge by a slight but characteristic mark, small traits give the clue to the character of a person, deduce something from a small indication, identify a lion from its claws
sillybus: i, m., = σίλλυβον,
I a kind of thistle, Plin. 22, 22, 42, § 85; 26, 7, 25, § 40 (but the true reading, Cic. Att. 4, 5, 3; 4, 8, a, 2, is sittybus, q. v.).