A CASE OF CYCLOPIA 219 



cerebellum other than those entering by way of the corpus resti- 

 forme (Cr., figs. 27 to 37) and those arising in the dentate nucleus. 

 Even the medullary center of the flocculus is lacking in myelin, 

 whereas in the normal term foetus this area is usually well 

 medullated. 



The relations of the cerebellar peduncles are essentially nor- 

 mal. The corpus restiforme is but slightly medullated and shows 

 a very distinct and circumscribed nucleus (Nu.c.r., figs. 34 to 35) 

 after its entrance into the cerebellum. The pons, which is well 

 developed, contains no medullated fibers. The brachia conjunc- 

 tiva {Br.c, figs. 32 to 37) are readily distinguished, arising in 

 the nucleus dentatus and coursing ventrad and cephalad to 

 decussate caudad to the red nucleus. Their fibers are poorly 

 medullated. 



Nucleus ruber {Nu.r., figs. 37 to 42). The red nucleus is well 

 formed and prominent in the midbrain region. Owing to the 

 absence of the crusta and also of a well marked substantia nigra, 

 this nucleus is only separated from the periphery by a very short 

 distance. It is to be noted that the emergent fibers of the oculo- 

 motor nerve do not at any point pierce the substance of the red 

 nucleus as they do in the majority of cases normally. The ce- 

 phalic end of this nucleus is in relation with the lateral nucleus 

 of the thalamic mass. 



Superior colliculi {C.s., figs. 35 to 39). These form prominent 

 projections which are completely covered over by a thickened 

 layer of pia (P., figs. 31 to 46) which "surrounds the midbrain 

 region. The cellular elements are but poorly differentiated. A 

 few medullated commissural fibers pass across the mid-dorsal 

 line above the stratum album profundum {s.a.p.). In the mid- 

 line dorsal to the aqueductus (Aq.c.) in this region there is a 

 well marked oval mass of embryonal cells (A^^., figs. 36 to 39). 



The dorsal tegmental decussation of Meynert (D.t.d.M., fig. 

 37) is well shown ventral to the oculomotor nuclei. The ven- 

 tral tegmental decussation was also distinguished but is not 

 shown in the figures. 



Fasciculus reiroflexus of Meynert {F.r.M., figs. 38 to 46). 

 This bundle forms a prominent landmark in the region of June- 



