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The development of the olfactory organ of Kaloula borealis (Barbour) as compared with that of Rana nigromaculata Hallowell.

1946; The Company of Biologists; Volume: 87; Issue: 347 Linguagem: Inglês

1477-9137

Chi-Lan Tsui, Tsing-Hwa Pan,

Olfactory and Sensory Function Studies

1. The anlage of the olfactory placode of Kaloula borealis arises from the sensory layer of ectoderm as in Eana, but appears slightly later. 2. There is also no such structure as the oro-nasal groove. 3. There are present only the dorsal and middle lumina in the early developmental stage. A separate ventral lumen and the inward projection present in Rana are wanting in Kaloula. 4. The primitive choana opens into the endodermal part of the oral cavity as in Rana. 5. The external naris closes up after the formation of the primitive choana and is formed de novo at the beginning of the metamorphosis. 6. The floor of the middle lumen opens entirely into the oral cavity. The process which synchronizes with the closure of the external naris begins from the end next to the primitive choana and extends anteriorly. This compound opening forms the choana in the adult stage. 7. There are also three embryonic nasal sacs in Kaloula. Their mode of origin and prospective role in the formation of the mature nasal cavities are essentially identical with those in Rana. 8. The shrinkage of the nasal organ in metamorphosis is more proounced than in Rana. 9. The lateral appendices in Kaloula and Rana are alike in their manner of formation, change of position, and degeneration. 10. The formation of the median and lateral nasal glands, pharyngeal gland, and Bowman9s gland is similar to that found in Rana. 11. There exists a nasal gland, which is not known in Rana. It is designated as the middle nasal gland. 12. The naso-lachrymal duct differentiates under the skin as an epidermal ridge and is subsequently detached. It is initiated at the distal end of the closed entrance canal, but is later connected with its proximal end. When fully differentiated it opens into the latero-posterior part of the cavum medium at its proximal end.