86 BRITISH TYROGLYPHID^E. 



receptacular accessory gland" (PL B, figs. 1, 2, gar) ; 

 it is considerably larger than the chambered accessory 

 gland, and is probably the largest organ in the body 

 except the ventriculus : its form is inversely pyriform ; 

 the broader end being the anterior, next to the penis, 

 and the smaller posterior end being greatly truncated. 

 Both the broad anterior end and the narrower 

 posterior end are nearly straight ; in the centre of 

 the anterior end the short wide duct emerges and 

 discharges into the ductus ejaculatorius. The sides of 

 the gland are curved and somewhat irregular in form. 

 This gland has a thin tunica propria, and the walls of 

 the cells are fine and difficult to see, and never persist 

 if the cell be empty. These cells are large flat cells of 

 about 30 p to 40 ju in diameter, but of slight thickness ; 

 they are almost like pavement epithelium, except that 

 they are not sufficiently pressed against each other to 

 have assumed angular forms, and that the demarcation 

 between one cell and its neighbours is indistinct. 

 They stain deeply with carmine or hsematoxylin, have 

 round clear nuclei of about 15 /* to 20 p diameter, and 

 distinct nucleoli. Within this outer layer of cells the 

 whole interior of the gland appears to be hollow and 

 undivided, but is always full of a homogeneous or 

 extremely finely granular mass of secretory matter, 

 which stains only slightly (see PL B, fig. 2). The 

 arrangement reminds me somewhat of that of the true 

 testis in Bdella, where half the interior of the organ 

 consists of a chamber in which the sperm produced is 

 received and stored. In specimens which have been 

 subjected to the action of reagents for the purpose of 

 making preparations or otherwise, this mass of secretory 

 matter often breaks up into laminae, or hexagonal or 

 other forms which have a very deceptive appearance ; 

 but these phenomena do not exist during the life of 

 the creature. 



The male accessory glands of Hericia Eobini appear 

 to be very similar to those of Glycyphagus platygaster. 



In Tyroglyphus lonyior Nalepa only describes one male 



