178 THE COCKROACH : 



The ejaculatory duct is about '15 inch long, and overlies 

 the 6th-9th sterna. It is wide in front, where it receives the 

 paired outlets of the vesiculce seminales. Further back it 

 narrows, and widens again near to its outlet, which we find to 

 be between the external chitinous parts, and not into the penis, 

 as described by Brehm. The duct possesses a muscular wall 

 for the forcible ejection of its contents, and in accordance with 

 its origin as a folding-in of the outer surface, it is provided 

 with a chitinous lining. In the adult the fore part of the duct 

 may be distended with spermatozoa. 



Fig. 101. Vesiculse Seminales and Ductus Ejaculatorius of Pupa. FZ>, vas 

 cleferens. X 28. 



The ejaculatory duct is originally double (p. 194), and its 

 internal cavity is still subdivided in the last larval stage or 

 so-called " pupa." 



Upon the ventral surface of the ejaculatory duct lies an 

 accessory gland of unknown function ; it is " composed of 

 dichotomous, monilated tubes, lined by a columnar epithelium, 

 all bound together by a common investment into a flattened, 

 elongated mass." * The duct of this gland does not enter the 

 penis, as described by Brehm, but opens upon a double hook, 

 which forms part of the external genital armature (fig. 99, 3). 

 It may be convenient to distinguish this as the " conglobate 

 gland."f 



* Huxley, Anat. Invert. Animals, p. 416. 



f The term "accessory gland," used by Huxley and others, is already appropriated 

 to glands which we believe to be represented by the utricles of the Cockroach, and 

 which have only a general correspondence with the gland in question. 



