6.5 mm in diameter at the end of the period are found within the ovaries. Development of these ova takes place during the hibernation period from early April to the beginning of September, continuing in the early spring until ovulation takes place in the first weeks of October.

Following the rupture of each follicle at ovulation a pale corpus luteum develops within the ovary of L. zelandica and persists until parturition takes place some twelve weeks later. Counts of the corpora lutea present have been used in this study to determine the number of ova released by each ovary in L. zelandica.

The presence of a corpus luteum in reptiles has been recognised since Strahl (1892) described the corpus luteum in Lacerta agilis. Weekes (1934) reviews the early work and describes the corpus luteum in a number of oviparous and viviparous reptiles, including Lygosoma (Leiolopisma) weeksae and Lygosoma (Leiolopisma) entrecasteauxt as well as three other scincid lizards. In the viviparous lizards examined by Weekes the corpus luteum persists for approximately three and a-half months, degeneration beginning at about the end of the second month of pregnancy. By the time of birth of the young, the degeneration has spread through all the luteal tissue, which disappears two weeks after the birth of the young. Boyd (1940), Dutta (1944) and Miller (1948) further established that well developed corpora lutea are formed in several other families of lizards.

The average mass of the ovum at ovulation is 0.10 gm and the average mass of the newly born young 0.26 gm. It follows, then, that more than half the total weight of the fully developed young must be derived from materials transported across the oviduct wall. Thus some form of placentation exists in L. zelandica and the species is truly viviparous, the ova being retained in the oviducts as is the case in all other New Zealand lizards.

Placentation is known to occur elsewhere in the family Scincidae, and Weekes (1935) in a review of placentation among reptiles records two types of placentation within the genus Leiolopisma. The placentation of five Australian members of the genus has been examined: Lygosoma (Leiolopisma) pretiosum, L. (L.) ocellatum, and L. (L.) metallicum (Weekes, 1930). These have a simple type of placentation whereas Lygosoma (Leiolopisma) entrecasteauxi (Harrison and Weekes, 1925) and L. (L.) weeksae (Weekes, 1929) have an extremely specialised placenta. The nature of the placentation in L. zelandica has not yet been examined.

The mature oviducts are superficially pleated externally, folded and flattened against the dorsal body wall. The right oviduct, 18.0 mm to 22.0 mm long, is 4.0 mm or 5.0 mm longer than the left. In immature females the oviducts are folded for the first third of their length, and the remaining portion is a flat ribbon-like band of semi-opaque tissue 1.0 mm to 2.0 mm wide (Text-fig. 3). The gravid oviduct is greatly distended and appears as though chambered. The oviducts of mature females are generally folded and pleated throughout their entire length, especially following parturition, but do not show the distinct “incubatory chambers” which persist in some other lizards.

The first two newly-born young of the 1954–55 breeding season were caught within the study area on January 20, 1955. No more were captured for four days, despite prolonged and careful searching. Then 16 newly-born lizards were taken on January 25 and 26, ranging in size from 24.5 mm to 28.0 mm snout-vent length. The newly-born lizards grow rapidly, and as the first two lizards caught on January 20 were 28.0 mm and 29.5 mm from snout to vent they may have been born towards the beginning of January. A large female weighing 5.2 gm before parturition gave birth to six young from 0.26 to 0.28 gm in weight and averaging 24.9 mm in snout-vent length. Both size and weight appear to be fairly constant for newly-born young. Twenty-two young lizards were caught during the following ten weeks, and by comparing their size with the known rate of growth it could easily be seen that none could have been born later than the middle of February. By the end of February all lizards captured were above 30.0 mm from snout to vent.