1 10 PERCIVAL HAILEY 



SUMMAliV 



1. The plexus chorioideus ventriculi lateralis is composed of 

 two distinct portions, of which the anterior is developed from 

 the roof plate in the angle between the paraphysal arch and the 

 medial wall of the hemisphere, and the posterior from that 

 part of the medial wall of the hemisphere just anterior to the 

 di-telencephalic groove and homologous to the anterior hmb of 

 the velum transversum. 



2. The taenia fornicis of adult human anatomy, except for 

 its extreme anterior end, is not homologous with the taenia 

 fornicis of Anura. 



3. The position of the recessus neuroporicus could not with 

 certainty be ascertained, and identification of the lamina supra- 

 neuroporica was therefore uncertain. 



4. The tela chorioidea telencephali medii is present in the 

 embryos of 28 and 32 mm. 



5. The paraphysal arch can be followed to the embryo of 32 

 mm., as an arch of the roof plate of the telencephalon. It lies 

 just anterior to the velum transversum and from its sides arise 

 the lateral choroid plexuses. The anterior pouch of the choroid 

 plexus of the third ventricle lies in the diencephalon and is not, 

 therefore, homologous to the paraphysis of the lower verte- 

 brates. No indication of the development of a glandular struc- 

 ture was found. 



6. The velum transversum can be traced up to the 32 mm. 

 embryo, joining the anterior extremities of attachment of the 

 tela chorioidea diencephali to the lateral thalamic wall, and 

 its groove is continuous laterally with the angle between the tae- 

 nia chorioidea and the lateral thalamic wall, the di-telencephahc 

 groove. 



7. The tela chorioidea diencephaU is not folded nor vascular- 

 ized except for its extreme anterior end in the embryo of 32 mm. 

 It is broadened by the formation of a thalamic lip, very much 

 resembling the rhomboidal lip of the rhombencephalon. 



8. The epiphyses of all three embryos show indications of 

 the presence of the homologue of the pineal vesicle of the lower 



