Close association between lungs and gonads in the amphibian Pleurodeles waltl. (a), Anterior part of the testis (APT) associated with the lung (Lu) in a 9.5-month-old male: the enlarged posterior part constitutes the first testis lobe (1TL) and the fat body (FB) associated with the gonad is well developed. (b), Histological section of a 5-month-old male larva showing a fold of the peritoneum (FPe) linking the lung (Lu) to the mesonephros. (c), More posterior section of the animal shown in b showing the lung (Lu) separated from the fold of the peritoneum which here encloses the gonad (Go) and the fat body (FB). (d), Histological section showing the connective tissue common to the lung (Lu) and the testis in a 9.5-month-old male; lobules (Lo) containing primordial germ cells are present. (e), Enlargement of the area shown in (e); the connective link contains lobule cells (LoC) surrounding primordial germ cells (PGC) with their typical large polylobular nucleus. Outside the lobules, somatic cells (SC) possess a very small nucleus.