The brain of Acipenser. Di 
dd 
certainly at least a part of the fornix ends here. In addition, the 
corpus mammillare receives a bundle from the nucleus anterior, 
tractus thalamo-mammillaris or bundle of VıcQ p’Azyr in Mammals. 
EDINGER describes this as a constant bundle from the Amphibia 
onward and it has been described above for Acipenser. In Mammals, 
the recent descriptions by S. Ramon y Cagau (96) and KOLLIKER 
(96) represent this bundle as composed of collateral fibres from the 
Haubenbiindel of the corpus mammillare. The fasciculus mammillaris 
princeps arises from the corpus mammillare, runs dorsally, its fibres 
divide into two branches, the bundles thus formed diverge, one 
ending in the dorsal part of the thalamus (bundle of Vıca D’Azyr), 
the other ending in the vicinity of the nuclei of the III and IV 
nerves. EDINGER’s investigations extend over all classes of Ver- 
tebrates and his description of the tractus thalamo-mammillaris is 
certainly correct for fishes. No bundle is clearer in my preparations 
than this. On the other hand, the descriptions of CAJAL and KÖL- 
LIKER are so exact that they must be accepted for Mammals. It 
is therefore necessary to recognize two sets of fibres: the bundle of 
VicQ D’AzyR in Mammals having the structure described by CAJAL 
and KOLLIKER, and the tractus thalamo-mammillaris as described 
by EDINGER and myself, present at least in the lower Vertebrates. 
In his last ‘tween brain paper (99) EDINGER describes the tractus 
thalamo-mammillaris in Reptiles as coming from the nucleus anterior, 
and describes also a tractus tegmento-mammillaris which apparently 
corresponds to the Haubenbündel of CAJAL and KOLLIKER. 
Fibres go out from the corpus mammillare in two tracts, the 
ascending fibres of the tractus strio-thalamicus and the tractus mam- 
millo-bulbaris (page 118). The former were first described in fishes 
by VAN GEHUCHTFN (94) in the trout. The latter has been de- 
scribed by EDINGER in birds (96) as the tractus mammillo-peduncu- 
laris. The peduncularis corporis mammillaris of KÔLLIKER (96, 
p. 515) is possibly the same bundle in Mammals. 
The physiology of the corpus mammillare is somewhat more 
complex than that of the lobus inferior. Impulses are received from 
secondary olfactory and optic centers (olfactory nuclei and cortex, and 
nucleus anterior). A relatively small number of fibres are sent to 
the medulla (in Mammals to the base of the mid brain), presumably 
to motor nuclei. The greater part of its fibres pass up to the 
epistriatum, from which impulses are sent to the striatum, and thence 
pass to the central grey of the thalamus where they may reach motor 
