J 46 



Tlie following three figures of tiiis embryo (fig. II, 12 and 13), 

 show very clearly the presence of the lamina mednllaris externa 

 between the hyperstriatnm inferius c and the pulaeostrmtuni. b, and 

 also the fact that this lamina is a place of predilection for blood- 

 vessels (v. s. =r vasa sangninea). In fig. 11 this lamina has become 

 specially i^lear by the retraction of the tissne (these are silverpre- 

 parations), which retraction finds a natural place of predilection at 

 this spot on account of the loose character of this lamina to which 

 I already referred. 



M. 5. 



Fig. 11. Sagittal section of a'chickembryo of 11 days, lateral to fig. 10. 

 By the retraction of the tissue the vascular cavities (v. s.) in 

 the lamina inedullaris externa are very evident. 

 d = hyperstriatum superius, c = hyperstriatum inferius, 

 b = palaeostriatum augmentatum = mesostriatum). 



Figures 12 and 13 moreover show us that ■ the hyperstriatum 

 superius (/ diminishes in lateral direction while c enlarges acquiring 

 its connection with the frontal iialliuin, near the ecfostriatum (E. S.). 



It is farther of interest to note in fig. 11 and 12 that a part of 

 the palaeostriatum b continues with and underneath the hyper- 

 striatum inferius bending l)ackward over the recess of the ventricle 

 (above the secondary epistriatuni or archistriatum E.). 



The caudal enlargement of the palaeostriatum with and under- 

 neath the hyperstriatum is what 1 have called \\\e substantia palaeo- 

 striatica catidata. 



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