SKULL OF A HUMAN FETUS OF 40 MM. 335 



outer surface of the condyloid portion just lateral to the hypo- 

 glossal canal (figs. 2 and 4). The straight line which joins the 

 outermost tips of the processes passes through their roots also, 

 and meets the median sagittal plane at a right angle, thus show- 

 ing that each process is perpendicular to the sagittal plane of 

 the head. The coronal plane in which this line lies cuts the 

 ventral foraminal prominences. Each process is prismatic in 

 shape, and thus presents three surfaces, which meet at the most 

 lateral point, or tip. The medial part of the cranial surface is 

 hollowed for the recessus jugularis; the lateral part lies outside 

 of the cranium (fig. 4), its convex area forming the outermost 

 termination of the caudal deUmitation of the jugular foramen. 

 Immediately above this convex surface appears the proximal, 

 curved end of the cartilage of Reichert. The remaining sur- 

 faces look ventro-caudally and dorso-caudally respectively, and 

 are separated by the caudal border, which projects downwards 

 in a ridge-like manner (figs. 2 and 3), and forms a prominent 

 object, when the skull is regarded from below, as it springs 

 laterally from the outer part of the ventral foraminal prominence. 

 The dorsal border is continuous with the lamina alaris. The 

 ventral border is free (figs. 2, 4 and 5), and is thin in its medial 

 half, where it bounds the recessus jugularis ventrally. From 

 within outwards it follows a curved line, convex ventrally, and, 

 in the region of the recessus jugularis, there is a small cranial con- 

 cavity, over which the jugular vein and accompanying nerves pass. 

 As has been observed before, this ventral border is the anterior 

 extension of the bifurcated upper border of the condyloid portion. 

 The left process presents a slight difference when compared 

 with the right. A small foramen (figs. 2 and 5) is seen to tunnel 

 under its ventral border, thus forming a passageway from the 

 recessus jugularis within to the ventro-caudal surface of the 

 process on the outer aspect of the skull. The outlet lies just 

 lateral to that of the hj^oglossal canal. Though the right side 



as Voit gives to the term "processus paracondyloideus." I have selected the 

 latter term, and used it in a more extended sense, as applying to the entire struc- 

 ture corresponding to the transverse (and perhaps costal) process of the occipital 

 vertebra, since this represents a morphological unit. 



