Sirena sirenae, or siren sirenis, is what the monster is called, which draws sailors to danger by the sweetness of its song; for this reason it is called this, from its drawing, as Huguitio says. However the gloss on Isaiah [Haymonis Halberstatensis Episcopi, Commentaria in Isaiam 2.13] says: Sirens are plumed, winged serpents. Others say, however, that they are fish of the sea, womanly in appearance. Papias, moreover, says: Sirens are great, plumed, flying dragons, as certain people think. Isidore, on the other hand, in book 20, where he deals with omens says this.

original latin

Sirenes tres finguntur fuisse ex parte virgines et ex parte volucres, ungulas et alas habentes, quarum una voce, altera tibia, tertia lyra canebat, quae illectos navigantes sub specie cantus ad naufragium pertrahunt.

In Arabia sunt serpentes cum alis qui sirenae vocantur, quae plus currunt quam equi, et volare dicuntur, quorum virus tantum est, ut ante mors, quam dolor sentiatur. De sirene autem dicit physiologus. Siren est monstrum marinum ab umbilico et sursum habens formam virginis, inferius figuram piscis. Haec belua in tempestate gaudet, in sereno autem dolet.

Haec dulcedine cantus facit dormire navigantes, quos cum viderit consopitos, ad navem accedit et quem poterit rapere secum ducit, et perferens ipsum ad locum siccum primum ipsum secum coire cogit, quod si coire noluerit, vel non poterit, illum perimit, et eius carnes devorat et transglutir*. De talibus monstris legitur in historia Alexandri Magni.