71 



June 12, 1838. 

 The Rev. F. W. Hope in the Chair. 



Mr. Owen communicated to the Meeting another portion of the 

 results attending his examination of the body of the ApterĮ/x, em- 

 bracing a description of the parts connected ■vvith the function of re- 

 spiration, and their general relations, as shown in this extraordinary 

 bird, to that structure of the respiratory organs which is so eminent- 

 ]y characteristic of the entire class. 



Mr. Owen remarks, that the system of respiration in birds is so 

 obviously framed with especial reference to the faculty of aėrial pro- 

 gression, and the peculiarities in the former exhibit so marked a phy- 

 siological relation to the latter, that in the Apteryx, where the Avings 

 are reduced to the lowest known rudimentary eondition, the exami- 

 nation of the accompanying modifications in the respiratory apparatus 

 presented a most interesting subject for inquiry. 



Upon carefully removing the viscera from the abdomen, Mr. Owen 

 ■was both gratified and surprised at linding no trace of air-cells in 

 the abdominal cavity ; the diaphragm being entire, and pierced only 

 for the transmission of the cesophagus and larger blood-vessels, as iu 

 the Mammalitt. 



The position of the diaphragm was almost horizontai, likę that of 

 the Ditgong, difFering from it principally in relation to the heart and 

 pericardium, -vvhich projected into the abdominal cavity, as through a 

 hernial aperture, the aponeurosis of the diaphragm being continuous 

 over the pericardium ; an approach towards the oviparous type in the 

 disposition of the viscera being thus preserved. 



In the origins of the diaphragm Mr. Owen found the crura of the 

 lesser musele exhibiting a greater degree of development than is 

 known to exist in any other bird ; the crura were entirely tendinous, 

 and arose from slight projections at the sides of the lašt costal ver- 

 iehra, their fibres expanding and being lošt in the large aponeuro- 

 tic centre; at the point of their expansion to join the aponeurosis a 

 small proportion of muscular fibre was observed. 



The abdominal surface of the diaphragm, as in the Mammalia, was 

 principally in contact with the convex surface of the liver, but the 

 thoracic surface of the former was separated from the lungs by a se- 

 ries of small but well-marked air-cells, one of which projected 

 slightly through the anterior aperture of the thoracic-abdominal 

 cavity at the base of the neck ; the Apteryx thus still retains the 

 omithic type of structure, although presenting us with the only 

 known instance, in the feathered race, of a species in which the recep- 

 tacular portion of the lungs is not extended into the abdomen. 



The lungs were each of an irregular sub-compressed triedral fi- 

 gure, broader anteriorly and contracted toįvards the posterior ex- 



No. LXVI. — Pboceedings of the Zoological Societt. 



