1896.] MB, r, E. BBDDAED ON DISSUIIA EPISCOPTTS. 233 



Giconia ; and it may be possible to regard it as congeneric with 

 Ahdimia, remembering that botli are AfricaiH in range. In any 

 case we have here a distinct relation between structure and 

 geographical distribution. 



The Storks and Herons are contrasted by other structures than 

 those to which reference has already been made in the present 

 communication. I desire now to call the attention of the Society 

 to certain structures which have not hitliertq been used in this 

 connection, and which indeed have been but little made use of in 

 the systematic arrangement of birds. These characters are drawn 



Fig. 2. 



Syrinx of Abdimia sphenorhyncha. 



from the number and position of the muscles of the lungs, those 

 muscles which usually arise from the ribs and expand over the 

 pulmonary aponeurosis. To the complete set of these muscles 

 the term " diaphragm " has been applied. But at the present 

 moment I am not concerned with their general morphology, but 

 with their use in detailed classification. 



It has been stated by Prof. Weldon ' that in the Storks " the 

 pulmonary aponeurosis is not muscular." So far as my experience 

 enables me to say, that statement is nearly but not absolutely 

 true. 



In a specimen of Ciconia alba I found a single muscle on each 

 side of the body arising from the most anterior of the ribs bordering 

 upon the lung, and lying just in front of the anterior intermediate 

 air-sae. The rest of the pulmonary aponeurosis was perfectly free 

 from muscles. On the other hand, the Herons are well provided 



• " On some Poinis m the Anatomy of Phoenkopterui," P, Z. S. 1883, p.. §40. 



