Morphology as a function of age. Individuals at four weeks (A), 27 weeks (B) and 76 weeks (C) of age. The brain, left testis, left ovarium and a developing egg are outlined in (A). Furthermore, the organs that can be easily observed are named. B: brain, E: eye, G: gut, which is filled with yellowish diatoms, T: testis, O: ovarium, D: developing egg, S: copulatory stylet. With advancing age, internal organs become less distinguishable as shown for the left testis as an example (A: full line; B: dotted line; C: no line). Furthermore, the body becomes more opaque as a function of age. The opaqueness is, however, variable between individuals and in this figure, it can be best observed in (B). Another characteristic change is the appearance of bulges and grooves in the epidermis. As a result, the right eye is out of focus in (C). The occurrence of body deformities such as cysts (Cy) is also frequently observed. Scalebars: 100 μm.