Sill i'i:Li>r : Osteology of ihe Herodh nrs. 



i9< 



ably several others, this compound hone. Very faint traces of another 

 such a process may be seen marking its side farther back, and above- 

 it the barest hint of the centrum of the corresponding vertebra. For 

 the rest, the pygostyle is an irregular, cjuadrilateral plate, less than a 

 centimeter deep, and a little more than one long, measured on its 

 longest diameter. It has a round, thickened posterior margin, and its 

 upper and lower edges are sharpened. A pit marks the Hat anterior 



Fig. 29. Superior view of the skull of Nycticorax violaceiis, juv. Natural size, and 

 the same specimen as shown in Fig. 30. Drawn by the author. 



surface, which continues for a short distance into the substance of the 

 bone, the neural canal of the caudal vertebrae. Other Herons have 

 the pygostyle rather differently fashioned from this, though in each 

 instance the leading features are present. 



Fig. 30. Superior view of the mandible of Nycticorax violaceiis. Drawn by the 

 author, natural size from the specimen. From the same skeleton as Figs. 28 and 29. 



Of the Appendicular Skeleton. The Pectoral Limb : Ardca herodias 

 has a highly pneumatic hi/nierus, which in the well prepared skeleton 

 is a snowy-white, and for its size a wonderfully light bone. The 

 ])neumatic aperture is of small dimensions, it being a sub-elliptical 

 opening at the usual site for this orifice in birds. It differs some- 



