MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



307 



aud their undoubted origin from the cerebral ganglia. Hence these bodies appear to be differen- 

 tiations of the cerebral ganglia or lobes, having no connection either with the optic or with the 

 antennal lobes. These bodies have, as stated in my essay, attracted a good deal of attention 

 from writers on the brains of insects. 



Dujardin, in 1850, flrst drew atteution to them. His memoir we have not at hand to refer to, but as stated l)y 

 Newton — * 



"Dujardin pointed out that iu some insects there were to be seen upon the upper part of the brain certain 

 convoluted portions which he compared to the convolutions of the mammalian brain, .and, inasmuch as they seemed 

 to be more developed in those insects which are remarkable for their intelligence, such as ants, bees, wasps, etc., he 



Fig. rx.— Diagrammatic outlinoa of sectioua of tlie upper part of the brain of a cockroacb. Only one aide of the brain ia here repreaenloil. 

 The numbers indicate tiie position in the series of 34 sectious iulo wliicb this brain was cut. Mi. mushroom bodies with their cellular 

 covering; c, and their stems fut) ; a, anterior nervous mass : vi. median nervous mass. — After Newton. 



seemed to think the intelligence of insects stood iu direct relationship to the development of these bodies. The 

 form of these structures is described by the same author as being, when fully developed, as in the bee, like a pair 

 of disks tipon each side, each disk being folded together and bent downward before and behind, its border being 

 thickened and the inner portion radiated. By very careful dissection he found these bodies to be connected on each 

 side with a short pedicle, which bifurcates below to end in two tubercles. One of these tubercles is directed 

 toward the middle line, and approaches but does not touch the corresponding process of the opposite side. The 

 second tubercle is directed forward, and is in close relation to the front wall of the head, being only covered by the 



* On the Brain of the Cockroach. 

 341, 342. 



By E. T. Newton. Quart. Journ. Microscopical Science, July, 1879, H, pp. 



