ANATOMICAL NOMKNCLATURE. 131 



that of a passive organ, receiving the sperm and transmitting it into tlie 

 genital cleft of the female lender the pressure of the blood which enters 

 into the haematodocha through the meati sanguinis. 



The receptaculum, in the region of the embolus, is throughout its whole 

 length fine, smooth, and without pores. Further toward its closed extremity 

 is a mass of minute ducts which pierce the walls, and which 

 Q , Wagner has named meati sanguinis, blood ducts. All spiders 



are provided with these ducts, and their role is to serve as con- 

 duits to the blood from the htematodocha into the receptaculum. 



The Tegulum is a quite thick plate of chitine serving to cover in from 

 above and to protect the receptaculum. Many spiders, as the Attids, Thom- 

 isids, and others, have here no chitinous conformation except the tegulum ; 

 but sjiiders which have a more complicated organism of this apparatus 

 are provided with many other auxiliary organs, in the form of laminae, 

 dentations, and excrescences of the most unique and varied forms. The. 

 embolus is an organ of a chitinous nature, for the most part subiliform or 

 having the form of a switch. At its extremity there is a small orifice 

 (Fig. 98, or), by which the sperm enters and issues. The articulation of 

 the embolus with the tegulum may be mobile or immobile. 



The action of the above parts is as follows: The male applies to the 

 genital cleft of the female the exterior face of his palp, and by numerous 

 contractions of the abdomen, in which the subcutaneous muscles 

 ' take part, forces the blood through the orifice into the cavity 

 of the hannatodocha, which it expands, pushes out the copulatory appa- 

 ratus, and having by way of the blood ducts penetrated into the cavity 

 of the receptaculum seminis, impels the sperm through the embolus into 

 the genital cleft of the female. When the blood begins to abate, returning 

 into the body of the male it fills anew the sac as full as at first, an opera- 

 tion which is repeated until fecundation is terminated ; then the palp is 

 witlidrawn from the genital cleft, the haematodocha contracts, and the 

 tegulum resumes its position.^ 



1 La Mue des Araignees, M. Waldemar Wagner, Ann. Sc. Nat. Zool., 1888, 367-371. 



