448 Mr. W. P. Py craft on the Pterykgraphy $c. 



shaking of the plumes is probably effected by rapid waves of 

 contraction and expansion of the erectile muscles ; and this 

 is aided by strands of minute muscle passing from feather 

 to feather. 



The excessive development of muscular tissue beneath the 

 skin of the neck, by which the skin becomes thrown into 

 innumerable tiny rugosities and folds, is hard to explain at 

 present. 



Text-fiff. 81. 



Side view of dissection of Paradisea minor, to shew the dermal muscles 



used for the purpose of erecting the lateral plumes. 



pi. ye«£.=pteryla ventralis; p.rt.a. = pectoralis ahdominalis pars anterior; 



/>. a.j>.=pectoralis abdominalis pars posterior; /* = head of humerus. 



The following more technical description of these and 

 other muscles may prove of value for morphological 

 purposes. 



Myology. 



Onlv those muscles will be described here which are more 

 or less directly concerned with the production of the display. 

 The nomenclature adopted, unless otherwise stated, is that 

 of Fiirbringer. This description, it should be remarked, is 

 based on specimens preserved in spirit in the British Museum 

 and the collections of the Zoological Society of London. 



Cucullaris dorso-cutaneus. — This muscle, a derivative of 

 the cucullaris, is in Paradisea minor and P. apoda well 



