SKULL OF A 43-MM. HUMAN FETUS. 97 



2. The outlines of the external form, brain, frontal, and parietal bones, and 

 the chondrocranium, as seen from the right side, have been drawn by profile recon- 

 struction, to show their common relationships. 



3. Mucous membrane of the nose, showing relation to the nasal septum and 

 vomeronasal organ and to the developing conchae. 



4. The vomeronasal organ is plainly indicated and is situated one upon either 

 side of the septum. It is considerably above the paraseptal cartilages. 



5. Nasolacrimal duct system. The lower end, not yet connected with the 

 nasal cavity, is situated some distance behind the position which the corresponding 

 structure occupies in the lower forms and its migration backward may be connected 

 with the solution of continuity of the cartilaginous anterior transverse lamina. 



6. The following ganglia have been mentioned, and some of them have been 

 figured: semilunar, geniculate, sphenopalatine, cochlear, vestibular, jugular, and 

 petrous of glossopharyngeal, jugular and nodosum of vagus, accessory. 



7. The following nerves have been noticed and most of them have been figured : 

 trigeminal and branches, facial, chorda tympani, great superficial petrosal, nerve 

 of the pterygoid canal, glossopharyngeal, vagus, accessory, hypoglossal. 



8. Auditory tube and tympanic cavity are shown in their relation to the otic 

 capsule and ossicle primordia. 



9. Internal carotid artery is shown in relation to the otic capsule, carotid 

 foramen, and alar process of the developing sphenoid. Upon the alar process it lies 

 in the representative of the carotid sulcus. 



10. Membranous labyrinth and endolymphatic duct and sac. The slender 

 extension from the last mentioned lies medial to the anterior end of the occipito- 

 parietal groove. 



11. Stapedius muscle and tendon are shown in relation to the styloid process, 

 facial nerve, and surrounding structures. 



In conclusion, I wish to express my thanks to Dr. G. L. Streeter, Director of the 

 Carnegie Laboratory of Embryology, for the facilities of that Department, which 

 were freely placed at my disposal. 



