^4] SHUFELDT ON THE OSTEOLOGY OF SPEOTYTO. 97 



the neck; at the jimctiou on tlie posterior side i>s Ibniul a pneumatic 

 foramen of considerable size. These ribs are more or less flattened 

 above, from before backwards being convex anteriorly, concave poste- 

 riorlj", becoming rounded below. From the third to the ninth vertebra, 

 inclusive, appear beneath the vertebral canal anteriorly well-developed 

 styliform xoarapophj'sial processes, directed backwards and downwards. 

 They are best marked on the segments of the middle of the neck. There 

 is no instance in this bird of these processes being produced so far 

 backwards as to touch the next \^ertebra below ; their tips, as a rule, 

 about overhanging the middle of the centrum of the vertebra to which 

 they belong. We have found in specimens of Buho virfjinianus the 

 l)arapophyses of the fourth vertebra overlapping and touching the fifth 

 for a millimetre or more. The third and fourth cer\dcals have, beneath 

 in the median line posteriorly, strongly developed hypapophyses, quad- 

 rate in form, a process that exhibits itself on the fifth vertebra, ante- 

 riorly, merely as a small tubercle. On the sixth this tubercle has disap- 

 peared, and has been supplanted by two others that are now found just 

 within the periphery of the anterior facet of the centrum on the para- 

 pophysis of each side, beneath and inclined toward each other. These 

 processes, now a double hypapophysis apparently developed from the par- 

 apophyses, continue to increase in size and inclination towards each other 

 on the next three vertebrre, so that on the ninth, where they last appear, 

 they nearly form a closed canal. The passage between them is intended 

 for the carotids, to which they afford protection. The hypapophysis of 

 the tenth, eleventh, and twelfth vertebroe is single, large, quadrate, and 

 directed forwards and downwards. There are three on each of the last 

 two vertebrae, each having an independent root, the two lateral ones 

 directed downwards, forwards, and outwards, with characteristics similar 

 to the one in the median line. Several pneumatic and nutrient foramina 

 perforate each cervical vertebra at various points, except in the axis 

 and atlas, where, after diligent search, aided by the lens, we have sig- 

 nally failed to discover them. 



Dorsal vertebrce; vertebral and sternal ribs; sternum. — The dorsal 

 vertebrce number five ; the anterior one articulates with the last cervical 

 and the last dorsal with the first sacral. Although the dorsals of this 

 bird fit very snugly to each other, it requires no furtber masceration to 

 separate them from one another than it does to remove the ribs from 

 their attachments. This close interlocking, however, greatly diminishes 

 the movement of this division of the spinal column, bestowing upon it a 

 rigidity only exceeded by the anchylosed vertebrte of the sacrum ; yet, 

 it must be understood, they do enjoy, in this Owl, a considerable degree 

 of movement, especially laterally. The neural spines have here attained 

 their maximum development, forming, when taken together, an elevated 

 and compressed median crest, with a thickened summit, and having a 

 firm hold upon the remainder of the vertebrae below. Taken separately, 

 the last is the smallest, the fourth next, the first next, and the second 

 7 as 



