33© DISCOVERY REPORTS 



Stannius (1841) mentioned the network only very briefly in the course of a description 

 of the arteries of Phocaena phocaena. 



Carte and Macalister (1868) noted the plexus in Balaenoptera rostrata (= B. acuto- 

 rostrata). They found it mainly in the cervical region, within the rings formed by the 

 transverse apophyses of the cervical vertebrae. It reached behind as far as the fourth 

 dorsal vertebra. They noted that the plexus sent prolongations into the neural canal. 



Owen (1868), who gave to the networks the name "Retia Mirabilia", in his Com- 

 parative Anatomy of the Vertebrates described the rete in the porpoise as an "arterial 

 structure, formed chiefly by the intercostal arteries, lining the sides of the thorax from 

 the ninth and tenth pairs of ribs forwards, penetrating between the ribs near their joints 

 and behind the costal ligaments and there anastomosing with corresponding productions 

 from contiguous intercostal spaces; branches pass therefrom into the neural canal 

 surrounding the myelon with a similar plexus increasing in thickness near the skull and 

 about the macromyelon, anastomosing freely with the myelonal meningeal arteries". 

 Owen also mentioned a similar arterial plexus in the Piked Whale {Balaenoptera 

 acutorostrata) to which the internal mammary arteries also contribute. 



Turner (1872) mentioned the rete briefly in his description of the Blue Whale 

 dissected by him, and noted that the plexus was not confined to the thorax but extended 

 also into the neck and that prolongations were traceable into the spinal canal. 



Murie (1873) described various plexuses in the Ca'aing Whale (Globicephala melaena). 

 He mentioned a large network on the basis cranii from the tympanic bone forwards to 

 the maxillary and in the infundibular cavity of the mandible, and another at the root 

 of the Eustachian tube with capillaries connecting into a jugular channel. Mention was 

 also made of a deep lumbar plexus, described also by Owen in the porpoise, underlying 

 the lumbo-caudal muscles and "communicating with the two immense veins lying on 

 either side of the spinal cord". The plexuses, according to Murie, are essentially 

 composed of both arteries and veins. 



An excellent description of the rete mirabile of the Narwhal was given by Wilson 

 (1879). This author gave some description of the relation of the organ to the nerves of 

 the cervical and thoracic regions and was of the opinion that it is both venous and 

 arterial in constitution. 



Bouvier (1889), after summarizing the observations of Turner, Owen and Carte and 

 Macalister, proceeded to a description of the plexus in the dolphin (Delphinus delphis). 

 The intercostals, of which there are fifteen pairs, are all (except the first two pairs) given 

 off separately by unpaired trunks from the aorta. These are long in front and short 

 behind. Each bifurcates to give the corresponding intercostals. The two anterior pairs 

 of intercostals are given off by the thoracic arteries. The first intercostal of the succeeding 

 aortic series forms a plexus which is extraordinarily thick at the anterior extremity of 

 the thoracic cavity. Behind, it becomes very narrow and thin. Bouvier also described 

 and figured the plexus in Balaenoptera rostrata. He observed that the arteries outside the 

 plexus, but still very close to it, manifest a tendency to plexus disposition. They give 

 off minute arterioles which anastomose together and come into relation with the plexus 



