should rari be rare

[pmda]

In LLPSI Cap xxviii Orberg has the pilot of the ship telling Medus that pirates are rare in these parts.

Gubernator: "Nullum mare tutum est a praedonibus, ne mare Inferum quidem, quamquam rari huc perveniunt.

Why 'rari' and why not 'rare' the adv. presumably it means they rarely come here. Otherwise 'rari' is genitive sing. or nom pl masc but that doesn't make any sense to me..

[adrianus]

b. Mostly poet. and in post-Aug. prose for the adv. raro, seldom, rarely: “nec Iliacos coetus nisi rarus adibat,” Ov. M. 11, 766; cf.: “rarus, qui tam procul a portu recessisset, reperiebatur,” Quint. 12, prooem. § 3; so, “rarus fuit, qui, etc.,” id. 6, 2, 3: “antiquis scriptoribus rarus obtrectator,” Tac. A. 4, 33; Sall. H. Fragm. 3, 22, p. 233 Gerl.: “Caesar rarus egressu,” Tac. A. 15, 53; cf.: “leones rari in potu,” Plin. 8, 16, 18, § 46: “(calculus) rarus inventu,” id. 28, 15, 61, § 217; cf.: “helxine rara visu est,” id. 21, 16, 56, § 96: “Homerus alias circa picturas pigmentaque rarus,” i. e. rarely speaks of them, id. 33, 7, 38, § 115—

but also it just means "few" as a substantive ("few reach here") // et hunc autem sensum pauci tenet substantivum

B. Of any thing found in small numbers or which seldom takes place, few, rare (cf. paucus): “in omni arte ... ut in ipsâ virtute, optimum quidque rarissimum,” Cic. Fin. 2, 25, 81; cf.: “rarum genus (amicorum) et quidem omnia praeclara rara,” id. Lael. 21, 79: “raris ac prope nullis portibus,” Caes. B. G. 3, 12 fin.; cf.: “etiamsi rarus ejus rei, nonnullus tamen usus,” Quint. 8, 6, 30: “rarus enim est animus ad ea defendenda,” Sall. H. 3, 61, 7 Dietsch: “Idem rarum est, non sine usu tamen,” Quint. 5, 11, 42: “rari domos, plurimi amicorum tecta ... petivere,” Tac. H. 1, 79 fin.: “Oceanus raris ab orbe nostro navibus aditur,” id. G. 2: “aliquod solitarium aut rarum,” Cic. Inv. 1, 44, 83: “ut anteponantur rara vulgaribus,” id. Top. 18, 69: “litterae,” Liv. 6, 1; cf. id. 7, 3: “rara hostium apparebant arma,” id. 2, 50: “lites,” Quint. 7, 1, 43: “infelicitas,” id. 11, 2, 49: “quae (littera) est apud nos rarissima in clausulis,” id. 12, 10, 31: “quod est magis rarum,” id. 9, 2, 73: “ex maxime raro genere hominum,” Cic. Lael. 17, 64; cf. Quint. 7, 3, 25: “raris vocibus hisco,” Verg. A. 3, 314: “rara per ignotos errent animalia montes,” id. E. 6, 40: “audiet pugnas vitio parentum Rara juventus,” Hor. C. 1, 2, 24. —Rarum est, with ut: “rarum est, ut, etc.,” Quint. 3, 10, 3; 6, 3, 38; 10, 7, 24: “rarum dictu, esse aliquid, cui prosit neglegentia,” Plin. 18, 16, 39, § 140.