Things are beginning to take shape. The foetuses are now also growing rapidly and most "parts" are in their designated place. During the phase of 28 to 32 days, they are 25mm to 50mm big and it becomes difficult to determine the number of foetuses. Over the eye (that has been formed), an eyelid develops itself and there are small, triangular ears. The inner ear starts to differentiate into a complicated structure with which the animal can later hear; the eardrum is formed. On an image, the foetus already looks like a kitten. The ossification of several parts, still consisting of cartilage and where bone should usually be, goes on. The bronchi differentiate more and more. In female foetuses the womb develops. The liver, already present, is getting "lobed". The bladder develops. The size of the foetus is now 25mm to 50mm.