INTERNAL ANATOMY. 85 



which for want of a better name I will call the 

 chambered accessory gland (PI. B, figs. 1, 2, gac) 9 is a 

 large pyrif orm gland with the hinder end the larger ; 

 it discharges by a very short wide duct, not sharply 

 differentiated from the gland, into the ductus ejacula- 

 torius. It lies above the testes and above the other 

 accessory gland, and consequently near to the dorsal 

 surface; but further forward than the testes. This 

 gland has a stoutish tunica propria, but its whole mass, 

 except a small part round the duct, is divided into very 

 large cells varying from about 25 /u to about 50 /u in 

 length and from about 20 n to 30 ^ in breadth and 

 thickness, having nuclei of about 9 ^t to 12 /u in dia- 

 meter; these cells are crowded against one another 

 so that all rounded surfaces are lost, and they are 

 bounded by flat surfaces meeting at angles but very 

 irregular in form. The walls of these cells are thick, 

 almost like formed material, and they are filled with a 

 rather coarsely granular secretion which stains but 

 little either with carmine or haematoxylin. The secre- 

 tion is usually discharged by the breaking up of the 

 inner end of the cell ; the walls of the remainder of the 

 cell being left quite perfect and persisting ; so that 

 after the cells have been emptied, which seems to occur 

 one cell at a time, not all together, the gland is left 

 like an empty honeycomb only not so regular in form. 

 The histology of this gland, the persistency of the cell- 

 walls after the contents have been discharged, and the 

 nature of these contents, closely resemble those of the 

 great mucous glands of the male genital system of 

 Bdella ; and there is every reason to suppose that the 

 functions are analogous ; but the two glands cannot be 

 considered to be homologous, because the mucous 

 glands of Bddhi are really the vasa defer entia, which 

 in that genus have become enormously developed, and 

 have assumed a glandular function in addition to their 

 primary purpose. 



The second accessory gland in the $ reproductive 

 organs of Glycyphagus plctiyg aster I propose to call " the 



