ITS NERVOUS SYSTEM AXD SENSE ORGANS. 



95 



brain. Having had the advantage of comparing the model with 

 the original sections, we offer a short abstract of Mr. Newton's 

 memoir as the best introduction to the subject. He describes 

 the central framework of the Cockroach brain as consisting of 

 two solid and largely fibrous trabeculce, which lie side by side 

 along the base of the brain, becoming smaller at their hinder 

 ends ; they meet in the middle line, but apparently without 

 fusion or exchange of their fibres. Each trabecula is continued 

 upwards by two fibrous columns, the cauliculus in front, and the 

 peduncle behind ; the latter carries a pair of cellular disks, the 



OCX. 



P 



OCX* 



Fig. 45. A, lobes of the brain of the Cockroach, seen from within ; c, cauliculus; 

 p, peduncle ; t, trabecula. B, ditto, from the front ; ocx, outer calyx ; icx, inner 

 calyx. C, ditto, from above. Copied from E. T. Newton. 



calices (the cauliculus, though closely applied to the calices, is 

 not connected with them) ; these disks resemble two soft cakes 

 pressed together above, and bent one inwards, and the other 

 outwards below. The peduncle divides above, and each branch 

 joins one of the calices of the same hemisphere. 



This central framework is invested by cortical ganglionic 

 cells, which possess distinct nuclei and nucleoli. A special 

 cellular mass forms a cap to each pair of calices, and this 



