Volume 26, Issue 6
December 1947, pages 219-275
pp 219-232 December 1947
A study of the literature in the reproduction of bats reveals that there are two types of sexual phenomena exhibited by bats, some bats experiencing a definite hibernation during winter after copulation in autumn, and others where copulation is immediately followed by fertilisation and gestation in spring. The batScotophilus wroughtoni does not show any evidence of a winter “ sleep ” and thereby falls into the second category.
Scotophilus wroughtoni has a sharply defined breeding season, copulation occurring at about the middle of March and followed immediately by fertilisation and gestation.
The period of gestation is about 105 to 115 days.
The age which this bat attains, as determined by its pregnancy records, may safely be placed at about three years.
pp 233-235 December 1947
pp 236-275 December 1947
Cytogenetical studies in sesamum - Part I. Cytology of the parents,Sesamum orientale Linn, andSesamum prostratum Retz. and the cytology of the sterile hybrid between them and of the fertile amphidiploid
Interspecific crosses betweenSesamum orientale Linn, andSesamum prostratum Retz. were effected reciprocally and the sterile hybrid was made fertile by artificial induction of amphidiploidy through colchicine. The cytology of the parents and the hybrids was studied in detail.
Details of meiosis ofSesamum orientale, one of the parents employed have been worked out. The peculiar persistence of the nucleus and its movements during the meiotic cycle are recorded. The other parentSesamum prostratum has also been cytologically studied.
The irregular meiosis of the sterile hybrid and the occurrence of scattered bivalents and univalents in the metaphase plate, leading to the ultimate formation of abnormal sporads have been described fully.
The regular meiosis of the fertile amphidiploid is compared with the irregular meiosis of the sterile hybrid and the cause of this regularity is explained.
The nucleolus with behaviour of the special regard to its persistence and movements is discussed.
Interspecific hybridisation as a guide to ancestral homology and the artificial synthesis of a new species are discussed in the light of cytological data gathered in the present investigation.
The origin of the cultivated TilSesamum orientale Linn. from a putative ancestor having haploid number 7 through allopolyploidy is traced with the help of cytological details obtained in the hybrid meiosis.
The origin of the wildSesamum prostratum Retz. is also traced to an ancestral form possessing haploid number of 8 chromosomes through autopolyploidy.