Hastings' Dictionary of the Bible (1898)
SNAIL. The word thus rendered in Lev 11:30 may denote some species of Snail. lizard - perhaps the sand-lizard, which is found in the desert of Sinai and in many parts of Palestine. These creatures are eaten by the Arabs, but are esteemed unclean by the Jews. In Ps 58:8 the common snail or the slug is doubtless meant. The former is eaten by the Jews, as by most Orientals. These creatures, of many species, exceedingly abound in Bible lands. Snails seem to waste themselves by covering their path with a thick shining slime.
Though they secrete themselves in crevices of the rocks, yet during the long, dry summer multitudes of them perish from the heat, being utterly shrivelled and wasted away in their shells. The melting away spoken of in Psalms is doubtless to be taken in one or the other of these senses.