Contribution to knowledge of the morphogenesis of the nasal apparatus of the fallow deer (Dama dama L.).

As in the red deer, in the fallow deer embryo we found a number of ancestral structures reminiscent of relationships in other mammals, such as paraseptal cartilages, a septum nasi with trabecular widening, a lamina transversalis ant., a cart. ectochoanalis, a capsule wall with a roof and a lateral wall formed of a clearly distinguishable cart. parietotectalis and cart. paranasalis, an ethmoturbinale I projecting a long way rostrally and additionally, in the fallow deer, cart. paraseptales posteriores. I regard the relationship of the cart. alaris inf. to the parietotectal cartilage (or "marginoturbinale") as relatively "primitive"; this may mean that the term "atrioturbinale" is also justified in mammals and that the relevant structure is homologous with the one known by the same name in birds. The specializations found during study of the morphogenesis of the nasal apparatus in the red deer (Slabý 1990b) are accentuated in the fallow deer. The chief ones are the specific rostral processes of the anlage of the nasal septum, which are a significant part of reinforcement of the nostril, the marked widening of the nasal capsule in a lateral direction (so that even the paranasal cartilages have a largely horizontal course), the striking ventrolateral bulge in the nasal capsule at the beginning of the olfactory region and the final resultant decrease in the height (i. e. flattening) of the capsule. This leads to reduction of the frontoturbinalia and their corresponding recesses, which - where they are developed - are oriented more horizontally. The structure of ethmoturbinale I, together with its insertion, is also simplified. As in the corresponding red deer embryo, the paranasal cartilage zone in the anterior part of the olfactory region is strikingly thickened; the frontoturbinalia do not, however, originate (in our stage) by the formation of cavities in the cartilage, but develop as simple processes. A crista semicircularis and foramen epiphaniale and also, as distinct from the red deer embryo, cart. paraseptales posteriores, are clearly discernible. In conclusion, it can therefore be claimed that the morphogenesis of specialized cervid features is accentuated in Dama more than in Cervus and that relationships in the fallow deer represent a further step in specialization, or - if we are speaking of the development of radiations - specialization here has progressed further.