Of the brain of the human embryo. 



29 



the large ophthalmic and maxillary tributaries in front. In figure 27 it receives a 

 large terminal trunk lateral to the infundibulum made up of tributaries coming 

 from the region of the Sylvian fissure; this corresponds to the middle cerebral 

 vein of the adult. Caudally the cavernous sinus communicates with the main 

 blood-stream by means of the superior and inferior petrosal sinuses. The superior 

 petrosal sinus passes over the cochlear part of the otic capsule and empties above 



SIN. RECTUS 



SIN. SAGITTALIS SUP. 



PLEXUS TENTORII 



SIN. TRANS. 



EMISSAR. 

 MAST. 



V. OPTHAL 



FORAMEN 

 JUGULARE 



Figure 6. 



Profile reconstruction of the dural veins in a human embryo 50 mm. long (Carnegie Collection, No. 96). The 

 oiitlines of the veins of the falx cerebri can be seen through the cerel)ral hemisphere. That part of the 

 transverse sinus situated caudal to the superior petrosal sinus (sigmoid) shows practically the adult rela- 

 tions. The more anterior part is still in the form of a plexus embedded in the embryonic tissue of the ten- 

 torium. Enlarged 4 diameters. 



into the transverse sinus. The inferior petrosal sinus consists of a ple.xus of veins 

 that passes median to the otic capsule to empty at the point of origin of the internal 

 jugular vein. It is shown in figure 6 but not in figure 27. 



As regards the transverse sinus, it has been pointed out that the terminal or 

 jugular portion of it is established first. In both figures 5 and 27 it can be seen 



