Herrick, Morphology of Nervous System. 17 c; 



The lateral lobes in a median transection of the cere- 

 bellum form two large projections laterad, somewhat more 

 than half as large as the vermiform process dorsad, and about 

 half as large as the medulla ventrad to it. At this point the 

 recessus lateralis of either side (not to be confounded with 

 the ventricle of the lateral lobes) makes its appearance, be- 

 ing closed with the usual velum or protrusion of the endyma. 

 This membranous sac is small as compared to the develop- 

 ment in the sturgeon (Plate XI, Fig. 10). 



In Scaphirhynchus the volvula is enormously developed 

 and thrust far forward, completely obscuring the valve. Ap- 

 pearing first as a pentagonal projection from the inner 

 (dorsal) surface of the (inverted) valve, it goes on increas- 

 ing cephalad, till, rolling ventrad, it folds upon itself, turns 

 caudad, carrying its median protuberance upon its (now 

 ventral) surface, and passing somewhat dorsad to connect 

 with the vermiform lobe. The central portion consists of 

 white matter filled with enormous and beautiful branching 

 Purkinje's cells, the lateral portions containing the Deiter's 

 corpuscles. There is no bursa nor distinct cephalad 

 diverticle, as in Lepidosteus, but the vermiform lobe remains 

 a solid mass with its white matter mesad and dorsad and its 

 granular layer laterad and ventrad to the end (Fig. 11, 

 Plate XI). 



The lateral lobes are enormous and contain small ven- 

 tricles. Caudad, the dorsal portion is separated by the forma- 

 tion of the large recessus lateralis (Fig. 10, Plate XI) and 

 becomes a wing-like expasion of the vermiforme. The ven- 

 tral portion adheres to the latero-dorsal margin of the fourth 

 ventricle, retaining its characteristic structure far caudad. 

 Cephalad, the lateral lobes are perforated by several nerve 

 roots as beyond (Fig. 9, Plate XI). 



I am glad to acknowledge the kind assistance of Prof. H. K. Oshohn in securing 

 necessary literature for this article. — C. L. H. 



