Characteristic features in the "laryngotrachea" of Suncus murinus.

In the larynx of the Suncus murinus (house musk shrew), the cricoid cartilage was situated laterally to and overlapped with the 1st, the 2nd, and a part of the 3rd tracheal cartilages. The term "laryngotrachea" was used for the region maintained by both the cricoid cartilage and the tracheal ones. It is suggested that the condition of the cartilages in Suncus laryngotrachea is the most primitive condition in mammals. In the dorsal wall, just caudal to the plate of the cricoid cartilage and dorsal to the 3rd tracheal cartilage, there existed the "L-shaped cartilage" (named by the authors).