122 



Mr. P. A. Buxtoii on the 



Viallanes. These organs are the central body and the ocellary 

 glomerulus, and the stem and inner root of the mushroom 

 body ; the forward and backward roots are also buried in the 

 protocerebral lobes, but they are not definitely separated 

 from the surrounding parts by a free space. It may be 

 mentioned here that the mushroom body system is com- 

 pletely buried in the protocerebrum except at three points. 

 The parts which project are the head, the lower end of the 

 stem, and the tip of the forward root (see pp. 125 sqq.). 



oc.n. 



Text figube 1. — General relationships of the parts of the proto- 

 cerebrum. The organ is divided at the middle line and the left 

 side is shown in the figure, viewed from in front. The cut surface 

 shows the loge of Viallanes and the organs within it. No cells are 

 shown ; the whole organ as drawn here consists of axonic substance. 

 a, c, d, j, q, refer to tracts of fibres (see p. 136). br. bridge, d. I. 

 dorsal protocerebral lobe. hd. head of mushroom body. in. ca. 

 inner capsule of central body. in. r. inner root of mushroom body. 

 /. I. lateral lobes of protocerebrum. lo. la loge (Viallanes). mi. I. a. 

 and mi. I. p. anterior and posterior parts of middle lobe of proto- 

 cerebrum. oc. gri. ocellary glomerulus, oc. «. ocellary nerve, ou.ca. 

 outer capsule of central body. sw. hd. swollen head of ascending 

 branch of mushroom body. sw. st. swollen foot of stem of mushroom 

 body, to dm. tracts passing from protocerebrum to deuterocere- 

 brum. lu. tumulus, vl. I. a. anterior part of ventrolateral lobe. 



