Trachea Diffusion of oxygen and carbon dioxide takes place across the walls of the smallest tubes, called tracheoles, which penetrate tissues and even indent individual cells. Gas may be conducted through the respiratory system by means of active ventilation or passive diffusion. Unlike vertebrates, insects do not generally carry oxygen in their haemolymph. This is one of the factors that may limit their size. A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices. Taenidia provide strength and flexibility to the trachea. In the head, thorax, or abdomen, tracheae may also be connected
The Name of the Rose known as Bernard of Morlaix). Medieval manuscripts of this line are not in agreement: Eco quotes one Medieval variant verbatim, but Eco was not aware at the time of the text more commonly printed in modern editions, in which the reference is to Rome ("Roma"), not to a rose ("rosa"). The alternative text, with its context, runs: "Nunc ubi Regulus aut ubi Romulus aut ubi Remus? / Stat Roma pristina nomine, nomina nuda tenemus". This translates as "Where now is Regulus, or Romulus, or Remus? / Primordial Rome abides only in its name; we hold only naked names." Also the