http://en.wikipedia.org/wiki/Nose
In the most primitive living vertebrates, the lampreys and hagfish, there is only one nostril and olfactory pouch. Indeed, the nostril also opens into the hypophysis. This is not necessarily, however, a primitive trait, but one that may have arisen later in the evolution of these particular groups. For example, the fossil heterostracans had paired nostrils, and these were also a very early vertebrate group.
In the most primitive living vertebrates, the lampreys and hagfish, there is only one nostril and olfactory pouch. Indeed, the nostril also opens into the hypophysis. This is not necessarily, however, a primitive trait, but one that may have arisen later in the evolution of these particular groups. For example, the fossil heterostracans had paired nostrils, and these were also a very early vertebrate group.
No comments:
Post a Comment