96 BULLETIN UNITED STATES GEOLOGICAL SURVEY. [Yol.YI. 



in seriation ; but gradually as this deviation proceeds, some requisite con- 

 dition is brought about when the climax is attained. The fact of the 

 presence of a neural spine on the axis is conveyed, though in a less 

 marked degree, to the third or next vertebra below, where it occupies a 

 position about in the middle of the bone. As we descend, this lirocess 

 becomes less and less prominent, being found set further back on each 

 successive vertebra ; it disappears about entirely at the tenth, after 

 which it rapidly begins to make its appearance again, assuming its for- 

 mer position in the middle of the vertebra, being q ui te evident in the twelfth 

 in the shape of a pointed spine, while in the fourteenth it bears the quad- 

 rate form, with extended crest, being the first step towards an assumption 

 of that notorious feature found further on in the dorsals. In the third 

 vertebra the space between the pre- and post-zygapophyses is almost en- 

 tirely filled in, a minute foramen on either side alone remaining, by a lam- 

 ina of bone extending from one i)rocess to the other, giving to this ver- 

 tebra a much more solid appearance, which in reality it possesses above 

 that attained by any of its fellows. This bony lamina is reduced in the 

 fourth vertebra to a mere " interzygapophysial bar" connecting the pro- 

 cesses, while in the next succeeding one or two vertebriie it occurs only 

 on the i>rezygapophyses more as a tubercle, being directed backwards,, 

 then disappearing entirely, is to be found again only on a few of the 

 last cervicals as an ili-deflued knob, still retaining its original position. 

 The diapophyses at, first project nearly at right angles from their re- 

 spective centra, then approach the median line by being directed more 

 backward near the centre of the cervical division of the colnmn, and on 

 nearing the dorsals again gradual!}' protrude more and more dire(;tly 

 outward. The prezygapophyses of the ninth cervical support well- 

 marked unapophysial tubercles, which are feebly developed also on a 

 vertebra or two both above and below the ninth. The joints between 

 the bodies of the cervicals of this Owl are uj)on the same i)lan as those 

 found throughout the class ; the anterior facet being concave from 

 side to side, convex from above downwards, the reverse being the case 

 with the posterior facets, and when articulated fitting accurately into 

 each other. The pleurapophysial elements, well-marked in all the cervi- 

 cals after passing the axis, become in the thirteenth vertebra a free 

 cervical rib, about three millimetres in length, without neck or true 

 head, being merely susi)ende(l on either side from the diapophysis of 

 the vertebra, and freely inovable on its exceedingly minute articulating 

 facet. 



Attached to the last cervical we find the second ])air of free pleura- 

 I)ophyses, about two-thirds as long as the first pair of dorsals or true 

 ribs of the thorax, terminating in pointed extremities and articulating 

 with the vertebra by both capitula and tubercnla, the former on ellipti- 

 cal facets, placed vertically on either side of the centrum at the anterior 

 margin of the neural canal, and the latter on rounded tacets beneath 

 the diaiDophyses. The tubercle on one of these ribs is nearly as long as. 



