LABIAL SALIVARY GLANDS 



63 



been protruded the oral lobes are then diverged by the contraction 

 of the retractor muscles of the furca and discal sclerites, and dis- 

 tended by the inrush of blood which keeps them turgid. 



The Labial Salivary Glands (hgs. 3, 31, Ib.sl.). These salivary 

 glands \\v in the haustellum ut the base of the oral lobes. The 

 glands, which are spherical in shape, are composed of a large num- 

 ber of gland cells somewhat triangular in shape. Each gland cell 



p.S- 



hy. 



gx 



icd. 



o.d. 



--{Ay 



'Vac. 



Fig. 31. Transverse section of labial salivary gland, to show the structure of the 

 gland cells (g.c). (Camera lucida drawing.) 



Itij. Hypodermis. icd. Intracellular duct. /).s. Pseudo-trachea. od. Opening 

 of intracellular duct into the permanent vacuole (vac.) of the gland cell. 



is 40//. in size, and possesses a large nucleus (12/i), and internal to 

 this a permanent circular vacuole (vac.) which is 16/u, in size, and 

 is lined by a thin chitinous intima. The duct of each gland cell 

 opens into the side of the vacuole (od.). The ducts (icd.) are 

 intracellular, and run from the centre of the gland, some of them 

 uniting, to form a number of fine ducts on the ventral sides of the 

 discal sclerites, which unite and open into the oral pits by a median 



