. The elasmobranch fishes . B Fig. 171. Arteries associated with the spiracle. A. Raja. (From Hyrtl.) B. Cetorhinus. (From Carazzi.) , internal carotid artery; op., optic artery; , pseudobranchial artery; , ramus anastomoticns. der net," the wonder net being composed of a coil of arteries connecting the part going to the spiracle with the part leaving it. A different condition is found in this artery in the rays. In these the spiracle is usually large and the blood supply to the filaments is better developed than in the sharks. The artery here takes its origin similarly from t
. The elasmobranch fishes . B Fig. 171. Arteries associated with the spiracle. A. Raja. (From Hyrtl.) B. Cetorhinus. (From Carazzi.) , internal carotid artery; op., optic artery; , pseudobranchial artery; , ramus anastomoticns. der net," the wonder net being composed of a coil of arteries connecting the part going to the spiracle with the part leaving it. A different condition is found in this artery in the rays. In these the spiracle is usually large and the blood supply to the filaments is better developed than in the sharks. The artery here takes its origin similarly from the first efferent- collector and as a large vessel (ps., fig. 171a) passes toward the pseudobranch. Before reaching the latter, however, it gives off a large branch to the adductor mandibularis muscle. At the pseudobranch it separates into numerous fila- mentous arteries, and then continues as a smaller artery () to join the internal carotid artery (), as in the sharks. On its way it gives off the ophthalmica magna to the eye. ]Much attention has been given to the function of the ramus anastomoticns. In some of the sharks in which the spiracle is closed and in w^hich the artery passes almost directly from the collector to the internal carotid, it is a true ramus anastomoticns. But in the rays it is composed of an afferent and an efferent part. It has been urged by Hyrtl (1858) that in the rays the branch connecting the internal carotid and the spiracular gill is the afferent branch
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