226 



ANNUL AT A. 



Sensory. 



presence of stigmata and absence of gills ; and (5) the terminal position 

 of the genital aperture. 



The antennae are tactile and, like the antennules of the 

 lobster, they are also said to possess olfactory 

 hairs. The palpi are also tactile. The eyes have 

 been already referred to. 



Fig. 150.— Dissection of Cockroach from the Dorsal Side. 

 (Ad nat. ) 

 Salivary Bladder. 

 Brain. 



I St Thoracic 



Ganglion, 

 ist Thoracic 



Stigma. 

 2nd Thoracic 



Stigma. 



I St Abdominal 

 Nerve Ganglion. 



:ard. 



~^.' 



Ovarioles. 



Stigmata, 



Ventral Abdo- 

 minal Muscles. -^=-^^^^^^^^^0^ It.^. , y Hepatic Caeca. 



..Malpighian Tubules. 



Rectum. 



Thi 



The : ody-wall is removed and the alimentary canal pulled over to the right, 

 ventral tracheal system is seen as white tubes leading from the stigmata. 



If the terga be gently cut off or freed by a scalpel the 

 principal organs of the body are exposed. The mouti 

 passes into a buccal cavity provided with a hare 

 Alimentary, ^j^-^-j^^^g tongue. The paired salivary glands 

 with salivary bladder^ open by ducts into this part. Thenc( 

 a delicate oesophagus passes gradually into a large and spacioui 

 crop. At the hind end of the crop is the small thick-wallec 

 gizzard^ provided with six chitinous teeth and strainers^ as ii 

 the lobster. 



