ON THE OSTEOLOGY OF NYCTOSAURUS. 127 
a proatlas, said by Zittel to occur in the pterodactyls, but of which there is 
no other evidencein this specimen. Since the removal of this bone from 
the matrix, it seems quite surely to be, rather, the anterior, median element 
of the hyoidean apparatus. One view, which I take to be the superior, 
is shown in Pl. XLI, Fig. 6, three times the natural size, and, in Fig. 7 of 
the same plate, is shown one of the articular extremities (2) from the side, 
much more enlarged. The bone is nearly flat, with the pointed extremity 
curved upward, and with the two articular extremities much more 
massive than the remainder of the bone; they are also directed upward. 
Each has a smooth, synovial articular surface, doubtless for the articula- 
tion of the cylindrical rods. On the opposite surface, near the articula- 
tions, there is a slight longitudinal ridge, and near the middle of the 
bone on each side, there is an elongated, oval surface, apparently for 
muscular attachment. The slender rods seem to agree quite with the 
hyoidean bones of other pterodactyls, but I cannot find that the triangu- 
lar bone has ever been described. 
VERTEBR-. 
Seven has usually been accepted as the number of vertebrz in the 
neck of pterodactyls. If, however, we consider that vertebra which 
bears the first rib articulating with the sternum to be the first dorsal, 
then I believe that the prevailing number of cervicals:in pterodactyls 
is eight. Ftrbringer has already expressed the opinion that there are 
eight vertebre instead of seven:* ‘Falls die Patagiosaurier zum Theil 
nur sieben Halswirbel besitzen, wie algemein behauptet wird, aber 
meines Erachtens erst noch zu erweisen ist, so ware eventuell anzu- 
nehmen, das dieselben durch eine geringgradige, kranial gerichtete 
Wanderung der vorderen Extremitét ihren urspriinglich aus acht 
Wirbeln bestehenden Hals um einen in das thorakale Gebiet tberge- 
henden Wirbel verkiirzten.” He further expressed the opinion that 
the vertebra which I had considered to be the first dorsal in Preranodon 
was really the eighth cervical. Ina later paper I stated that the eighth 
vertebra in the neck of JVyctfosaurus was a functional cervical, though a 
structural dorsal. . . . I have usually assigned this vertebra to the dorsal 
series because of its great structural differences from the anterior cervicals; 
but these differences are scarcely greater than those of the last cervical in 
the turtles. Owenry correctly located it in the neck. In his description 
of this vertebra in Dimorphodon he says: ‘‘ At the base of the neck or the 
beginning of the back, the vertebrze suddenly decrease in length; the 
hypapophysis disappears, or is represented only by a slight projection of 
*Jena. Zeitschr. f. Naturwissenchaft, vol. xxxiv, p. 665, 1900. 
+ Paleontograph. Soc., 1869, p. 69. 
