426 JOHN H. STOKES 



able diffidence, and with the full realization that Weigert prepara- 

 tions are no final settlement of the question, and that their most 

 convincing appearances may be deceptive. The grey matter 

 between the strands of the corpus trapezoideum in sections 

 somewhat posterior represents to all appearances the extreme 

 anterior limit of the ventral cochlear nucleus, traceable back 

 to the main mass without a break. Those famihar with Cajal's 

 figures will recognize in fig. 359 on page 819 of the Histologic du 

 Systeme Nerveux, Tome 1 (Azoulay), on the right hand side of 

 the section, approximately the same region, as he pictures it for 

 the cat. Comparison of the figures here given (figs. 6 and 7) 

 with Cajal's is very instructive as regards the differences between 

 the opossum and higher mammalian brains in this region. The 

 cerebello-acoustic or nucleo-cerebellar path is the only group of 

 fibers in this region labelled in his figure. In the opossum, another 

 group is apparent, consisting of fine fibrils from the grey matter 

 of the before-mentioned anterior part of the ventral cochlear 

 nucleus, which apparently pass upward on the lateral side of the 

 vestibular nucleo-cerebellar tract, gathering into slender strands 

 which closely skirt the medial border of the inferior brachium, 

 but are always perfectly distinct from it. These fibers follow the 

 general direction of the ascending vestibular fibers although appar- 

 ently distinct from them also and turn medianward to be lost 

 among the fibers of the roof. Somewhat more anteriorly these 

 slender stands are replaced by the coarser ones shown in fig. 7 — 

 absolutely identical in appearance with the perfectly characteris- 

 tic root bundles of the corpus trapezoideum, sharply defined, 

 standing out clearly against a paler background, and in one sec- 

 tion appearing as an almost continuous strip of fibers from above 

 the level of the highest part of Deiter's to the middle of the dense 

 mass of the undoubted corpus trapezoideum. The section drawn 

 is only averagely good in showing this relation. It however 

 brings out the entire difference in direction of the fibers from those 

 of the spinal tract, and their striking individuality as regards 

 origin at least. In the face of these appearances, which are con- 

 firmed by the newer series of transverse sections prepared in this 

 laboratory since this work was begun, and of the apparent impossi- 



