98 



THE COCKROACH : 



consists of smaller cells without nucleoli. Above the meeting- 

 place of the trabeculoe is a peculiar laminated mass, the central 

 body, which consists of a network of fibres continuous with the 

 neighbouring ganglionic cells, and enclosing a granular sub- 

 stance. The antennary lobes consist of a network of fine fibres 



'OC 



Fig. 49. Frontal section of Brain of Cockroach. C, cellular layer beneath neuri- 

 lemma; ICx, inner calix ; O Cx, outer calix ; GO, ganglion-cells ; P, peduncle ; 

 T, trabecula; Op, optic nerve ; AnL, antennary lobe. X 24. 



enclosing ganglion cells, and surrounded by a layer of the 

 same. It is remarkable that no fibrous communications can be 

 made out between the calices and the cauliculi, or between the 

 trabeculse and the oesophageal connectives. 



Sense Organs. The Eye of Insects. 



The sense organs of Insects are very variable, both in position 

 and structure. Three special senses are indicated by trans- 

 parent and refractive parts of the cuticle, by tense membranes 

 with modified nerve-endings, and by peculiar sensory rods or 



