252 MR. W. P. PTCEA^FT ON THE MORPHOLOaT AND 



Stnithio is remarkable in that, according to Beddard, the right and left lobes are 

 fused into a single heart-shaped lobe. There is a Spigelian lobe. The gall-bladder 

 is wanting ; and there is but a single bile-duct, which opens near the pylorus. 



Mr. Beddard found the free edge of the liver in Bhynchotus mfescens pierced by 

 three small vessels of the vennl portal system — a fact whicli, as he points out, has a 

 very lizard-like appearance. 



RESPIRATORY ORGANS. 



a. The Lungs (PL XLV. fig. 9). 



The costo-pulmonary muscles in Casuarius are short, thick, and powerful, five pairs 

 in all ; they arise from the thoraco-sternal articulation of the ribs and extended fanwise 

 on to the aponeurosis covering the lung. Those of Rhea are relatively longer than in 

 Casuarius. In Apteryx, according to Huxley [41], they form " broad flat bands," which 

 " take their origin from the vertebral ribs, at some distance below the attachment of 

 the pulmonary aponeurosis, and, proceeding obliquely dorsad and forwards, spread 

 out and are inserted into that part of the aponeurosis which covers the posterior 

 inferior facet. 



In the relative size and distribution of the ecto-, ento-, and para-bronchia, and in the 

 size of the vestibule, the flightless members of the Palceognathce do not appear to 

 differ much one from another or from the Neogiutthd'. 



In the lungs of a Casuarius unappendiculatus the bronchial rings extended backwards 

 as far as the 4th ento-bronchium. The inner border of the anterior and posterior 

 inferior facets of the lung are deeply sculptured by a system of numerous parallel 

 grooves of open tubes, closely packed and running along the surface of the lung from 

 the mesial border outwards so as to converge towards, and open into, a spacious 

 chamber communicating posteriorly and ventrally with the 1st ento-bronchium 

 (PI. XLV. fig. 9), further forwards and also ventrally into the anterior end of the 

 pre-bronchial ostium. These grooves give the ventral face of the lung, after the 

 removal of tlie aponeurosis, the appearance of having been bored by Teredos, the groove 

 representing a heraisection. They are crossed and recrossed by transverse strands of 

 tissue and punctured by minute apertures. 



They may be divided into two groups according to whether they are fed by a trunk 

 from the 1st or the iJrd ento-bronchium. Thus, as will be seen in fig. 9, all the 

 secondary grooves cephalad of the main trunk marked " ent. I." are fed from this, whilst 

 ento-bronchium III. supplies all the grooves caudad thereof. 



These grooves are converted into tubes by the pulmonary aponeurosis. 



b. The Air-s.\cs (PL XLV. fig. 8). 

 In Casuarius the p-e-hrovchial sac is paired, and extends forward on each side of 



