1885.] TROCHILID.E, CAPRIMULGI D.C, AND CYPSELID.E. 1103 



The bone is notably compressed in the vertical direction from bead 

 to apex, the former being unusually flattened for a representative of 

 this class. 



Rather more than the hinder third of the l)lade is bent abruptly 

 in such a manner as to have the angle occur on the inner margin, 

 with its aperture, quite an open one, to the outer side. Fro;n this 

 point to tlie shar{) apex, the blade gradually tapers away. 



When this pectoral arch is articulated the axis of the shaft of the 

 coracoid is approximately in a plane which is parallel to the plane of 

 the dorsal surface of the sternal body. 



Of the remninrhr of the A.v'ial Slceleton in certain Caprimulgine 

 Birds. — Nuttall's Whippoorwill and Chordediles each have eleven 

 vertebrae in their cervical region before we come to a segment sup- 

 porting a free pair of ribs. Each agrees, again, in having this first 

 pair of ribs rather long and without epipleural appendages. In the 

 Whippoorwill the next pair of ribs also have free extremities and 

 well-developed processes anchylosed to thom, while in the Night- 

 jar, these latter also being present, we find that the ends of the ribs 

 articulate with sternal ribs. These are of unusual type in a specimen 

 before me, being high up on the costal processes, exceedingly small, 

 indeed far smaller tlian I ever saw them in a bird of the same size, 

 and the one on the left side being anchylosed to the sternum. Pos- 

 terior to this pair of ribs Ijoth of these forms agree again, and that 

 in having four more pairs each. 



Of these, the first three fulfil all the requirements of true dorsal 

 ribs as we find them among birds generally. The last pair spring 

 from the sacrum, although their iisemapophyses also reach the 

 costal borders of the sternum. They do not have epipleural ap[)end- 

 ages upon them. 



It will be seen that this arrangement gives the Goatsuckers 16 

 movable vertebrae in the column before arriving at the first one 

 appropriated by the pelvis. 



Then, as well as I can manage to count in the adult specimens, 

 either of these birds has ten more segments in the pelvic sacrum. 

 Chordediles differs from the Whippoorwiils, however, in having six 

 caudal vertebrae and a pygostyle, whereas the latter have but five 

 and the terminal piece. In either genus the pygostyle has a long, 

 sharp, and straight superior border, and a thickened po>terior one, 

 especially below where a triangular flattened area makes its appear- 

 ance, and the bone is not nearly so deep in the antero- posterior 

 direction. 



With the exception of the tuberous apophysis of the axis, the 

 vertebrae in these birds are notable for the entire absence of the 

 neural spines until we find them developed in the dorsal series. 

 On the other hand, afier passing the four or five vertebrae in the mid- 

 cervical region that are marked by the open carotid canal, the hyp- 

 apophyses arc quite a prominent feature, and it is only in the last 

 two segments before the pelvis that these latter are absent. 



The lateral canals commence in the third vertebrae and extend 

 through the cervical series as usual. 



