 In the majority of species of caecilians , the young are produced by vivipary . Typhlonectes compressicauda , a species from South America , is typical of these . Up to nine larvae can develop in the oviduct at any one time . They are elongated and have paired sac @-@ like gills , small eyes and specialised scraping teeth . At first , they feed on the yolks of the eggs , but as this source of nourishment declines they begin to rasp at the ciliated epithelial cells that line the oviduct . This stimulates the secretion of fluids rich in lipids and mucoproteins on which they feed along with scrapings from the oviduct wall . They may increase their length sixfold and be two @-@ fifths as long as their mother before being born . By this time they have undergone metamorphosis , lost their eyes and gills , developed a thicker skin and mouth tentacles , and reabsorbed their teeth . A permanent set of teeth grow through soon after birth . 
