Herrick, Neurological lAiboratory Notes. 57 



clustre, which occupies a relatively small area anteriorly, but 

 increases caudad, occupies the lower median portion of the 

 mantle. It consists of flask-like or sensory cells with fibres 

 which can be traced ventrad to the ventral median portion of 

 the posterior part of the brain, i. e. the hippocampal region, 

 and seems to embrace the continuation of the olfactory tract." 

 If the sentence is perhaps awkward, it would nevertheless un- 

 mistakably indicate that the writer homologized the mesal and 

 caudal region of cortex with the " Ammonshorn " as he has 

 continued to do up to the present time, differing from Edinger 

 only in restricting the hippocampus to the caudal part and ex- 

 cluding the cephalic region of the calloso-marginal mantle area. 

 On page 145 a more explicit passage occurs. "The remaining 

 median part of the ventricle . . . separates a thick por- 

 tion of the mantle, corresponding in some respects with the an- 

 terior portion of the Ammonshorn." 



It is really remarkable that there could be any mistake as 

 to the view presented in the second paper referred to. On page 

 15 occurs the following passage: " The base (ventral surface) 

 of the hemispheres exhibits a slight protuberance in the latero- 

 caudal portion, which is due to the occipito-hasal lobe. (The use 

 of the word lobe is a pure convention from which no escape 

 could be found.) The latter is not a sub-division of the cortex 

 but a well-defined portion of the axial lobe. [It is the same as 

 Edinger's " kugelformiger Kern," which the latter now agrees 

 with the writer in considering an implicate or masked bit of cor- 

 tex.] This lobe can probably be distinguished in all Saurop- 

 sida. It is partially separated from the remainder of the axial 

 lobe by a fibre tract, and bears laterad and dorsad a film of cor- 

 tex which projects caudad as a free occipital lobe of cortex for a 

 short distance and terminates in a velum cerebri. The latter is 

 morphologically a part of the wall of the lateral ventricle, which 

 has lost its cellular elements and contains, at one point, the tae- 

 nia thalami. The extent to which this lobe [i. e. the occipital 

 not the occipito-basal, as understood by Edinger] is developed 

 varies greatly even in reptiles. It is reduced to a minimum in 

 birds. It contains the undoubted honiologue of the hippocampus, 



