Now, this foundation or basis is a body sui generis, arising on the spine of the feathered kinds, connected by means of large arteries and veins, and of a loose, porous, and spongy texture, in order that multitudes of ova may be produced from it, and that it may supply tunics to all; which tunics, when the yelks have grown to their full size, are distended by them, and then the tunics surround the vitelli, in the manner of sacks with narrower necks and more capacious bellies, very much like the flasks that are formed by the breath of the glass-blower. Fabricius then proceeds: “The yelks, as they proceed from small beginnings, from the size of millet or mustard seeds, and are at first not only extremely small, but colourless, as Aristotle says, so do they increase by degrees, and, according to Aristotle, become first of a paler and then of a deeper yellow, until they have attained to the dimensions familiar to all.” I, however, have observed ova vastly smaller than millet seeds, ova which, like papulæ or sudamina, or the finest grains of sand, (such as we have indicated as found in the roe of fishes,) almost escaped the powers of sight; their places, indeed, were only proclaimed by a kind of roughness of the membranes. EXERCISE THE FOURTH. _Of the infundibulum._ The next succeeding portion of the uterus of the common fowl is called the infundibulum by Fabricius. It forms a kind of funnel or tube, extending downwards from the ovary, (which it everywhere embraces,) and becoming gradually wider, terminates in the superior produced portion of the uterus. This infundibulum yields a passage to the yelks when they have broken from their foot-stalks in their descent from the ovary into the second uterus (so it is styled by Fabricius). It resembles the tunica vaginalis in the scrotum, and is a most delicate membrane, very easily dilatable, fitted to receive the yelks that are daily cast loose, and to transmit them to the uterus mentioned. Would you have an example of these structures? Figure to yourself a small plant, whose tuberous roots should represent the congeries of yelks; its stalk the infundibulum. Now, as the stalk of this plant dies in the winter and disappears, in like manner, when the fowl ceases to lay eggs, the whole ovary, with the infundibulum, withers, shrinks, and is annulled; the basis [stroma] and indication of the roots being still left.