130 ' AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



upon other parts of the apparatus. The Glandular Cells (gl.c) are situated 

 at the margin of the alveolus. The chitinous teguments above these in 

 the cymbium are pierced by a number of ducts, which eventually serve 

 as conduits for the secretions of the cells. 



The Hsematodocha is a delicate chitinous saclike organ, of which the 

 bottom is inserted into the alveolus, and the superior margin into the 

 inferior face of the tegulum. Thus the entire basal part (recep- 

 taculum seminis), which is situated under the tegulum, is within 

 the cavity of the sac. The walls of the hsematodocha are very 

 thin and plaited, so that if the sac be full it is able to attain large dimen- 

 sions. In its ordinary condition with most spiders it is folded in a spiral 

 and situated within the alveolus. 



The bottom part, by which the sac is attached to the concavity of the 

 alveolus, has a round orifice (orificium hsematodocb.se, or.hsem), which 

 unites the cavity with the lacuna of the cymbium situated beneath. Mr. 

 Wagner says that during fecundation the haematodocha is not filled with 

 sperm, as certain observers suppose, but at that moment is filled with 

 blood. Its role is to transmit, under pressure of its elastic walls, the blood 

 which has come to the lacuna into the cavity of the receptaculum seminis, 

 through certain fine ducts (meati sanguinis), by which the cavity of the 

 receptaculum is united with the cavity of the sac. It follows that the 

 function of the hsematodocha is that by its means the blood takes part in 

 fecundation by penetrating, although in small quantity, along with the 

 sperm into the genital cavity of the female. 



Upon the superior part of the copulatory apparatus, and in part within 

 the cavity of the hsematodocha under the tegulum, is situated a tube with 

 thick, chitinous walls, which in different species of spiders differs 

 Recepta- j n sna p ej length, and position. This is the receptaculum seminis 

 cu um (rec.sem). The extremity of that part situated under the tegulum, 

 the basal part of the tube, is always closed. The opposite end ter- 

 minates in an orifice at the summit of the embolus (emb). At the moment 

 of fecundation the receptaculum is filled with sperm. Its role is as follows : 

 Shortly after the moult it is filled with sperm, which the male has forced 

 from his genital orifice upon a woven thread or tissue previously prepared. 

 He plunges his palp into his drop of sperm, which, by the law of capil- 

 larity, mounts into the receptaculum through the orifice (or) of the embolus, 

 the only organ of the copulatory apparatus that receives and conserves the 

 sperm. The sperm can only be discharged by the orifice of the embolus 

 through which it entered. The slender ducts (meati sanguinis), which 

 serve to unite the receptaculum with the cavity of the lucmatodocha, are 

 of such extreme fineness that they cannot serve as a conduit for the sperm 

 into the hsematodocha, and it is only the blood plasm which, under the 

 pressure of the walls of the hamatodocha, can be made to penetrate h\\o 

 the cavity of the receptaculum. Consequently, the role of the latter is 



