26 Annals of the Carnf.oie Museum. 



spines of bone slender in comparison with the rather massive inturned 

 angular processes, each of which is pierced near its apex with the 

 pneumatic foramen, seen in so many of the class. The rami of the 

 mandible of this mountain plover make a very acute angle with each 

 other, and the upper margins are quite sharp, while they are rounded 

 inferiorly. Ossifications of the organs of special sense, as the eye and 

 ear, present nothing but their usual ornithic characters. 



Of the Axial Skeleton. — Twelve vertebrae, including the atlas and 

 axis, are found in the spinal column of the neck of all of our plovers. 

 The cup of the atlas is roundly notched behind to its center, and the 

 axis possesses a knob-like neural spine. In the third vertebra this 

 process becomes a small compressed square lamina, and in this segment, 

 too, we find an extensive quadrate hypapophysis below, and a minute 

 foramen on either side, in the bony plate joining the zygapophyses. 

 These features reappear in the fourth vertebra, but the foramen men- 

 tioned has so increased in size here that it is reduced to a mere inter- 

 zygapophysial bar. In the fifth, sixth, seventh and eighth, the neural 

 spine has disappeared ; the hypapophysial plates are longer and shal- 

 lower ; the parapophyses persist as parial and at the same time lateral 

 spines, directed posteriorly. The last four vertebrce of the twelve 

 under consideration are modified for the carotid canal. Upon them 

 the neural plates are suppressed. These four vertebrae are the longest 

 in the neck, and their post-zygapophyses, diverging from each other, 

 reach well backwards. In several respects the thirteenth and fourteenth 

 vertebrae are peculiar, and differ from the leading twelve cervicals. 

 They are broader, wider, and each supports a pair of free ribs with 

 well -developed tubercula and capitula ; the second pair, or those on 

 the fourteenth vertebra, may bear uncinate processes, situated low 

 down on the rib. The neural spines are still suppressed, but the hypo- 

 pophyses again make their appearance mesiad and beneath the centra ; 

 in the thirteenth it consists of a single plate, while in the fourteenth 

 a lateral oflshoot springs from each side of this, so that three lamelli- 

 form prongs are present in that segment. A deep pit, with overhang- 

 ing brim on each side of the centrum, is for the first time observed in 

 these two vertebrae as we descend the series. It becomes wider and 

 shallower as we pass through the vertebrae beyond, but does not dis- 

 appear until we pass to those united to form the sacrum. 



The succeeding six vertebrae, or the fifteenth to the twentieth in- 

 clusive, are all free, and all support true vertebral ribs that articulate 



