INTERNAL ANATOMY OF THE GAMASID.E. 307 



mode, but it has in its favour the fact that the vagina is a large opening, and that such 

 species as Gamasus ci'assus and G. crassipes, which have not any sacculus or correlated 

 organs, hut which have a spermatheca in the vagina itself, are, as shown at page 296, 

 fecundated by that opening. 



The other possible method is that the products of the male organs are ejected from 

 the narrow mouth of the capsule into the more or less trumpet-shaped mouth of the 

 ringed tubes in the cuticle joining the coxa of the third leg to the more chitinized part of 

 its acetabulum, and pass directly up the ringed tubes into the sacculus ; this is a 

 sufficiently simple method, and is rendered more probable by the similarity of the 

 situation of the opening to that by which Astacus and many other Crustacea and 

 Myriapoda are fecundated, although in these cases it is also the aperture for the 

 deposition of ova. The only objection which I see to this is the fact that the spermato- 

 cysts found in the sacculus undoubtedly appear considerably too large to have passed 

 through the ringed tubes ; this is a serious difficulty, but it is possible, and even 

 probable, that the ringed tubes may be capable of distension, and that the spermatocysts, 

 which are soft bodies, are capable of compression, and can be forced through very smal 

 apertures, just as the eggs are forced through even hard, not distensible, openings which 

 seem quite incapable of allowing them to pass. The weight of the objection is also 

 considerably modified by the circumstance that it practically has to be faced in either 

 explanation, for the large spermatocysts are found both in the cornu and the sacculus ; 

 and yet in Lcelaps acuta the tube leading from the camera spermatis to the cornu and 

 in L. vacua the tube leading from the cornu to the sacculus are scarcelv larger in 

 diameter than the ringed tubes, and yet if the spermatocysts be introduced into the 

 vagina they must pass through both these tubes before they can get into the sacculus, 

 but in the sacculus they are found abundantly. 



I had hoped to settle this question by actual observation, but I have found that it is 

 not possible to see sufficiently clearly to be quite certain whether the small end of the 

 spermatic capsule is applied to the opening of the vagina or to the mouth of the ringed 

 tube ; the whole capsule is certainly not introduced into the vagina as it is in 

 G. crassns, but the epigynum, which covers or borders the opening of the vagina, lies 

 just between the third legs, and therefore just between the opening of the ringed tubes, 

 and, being large, almost reaches them. In the position which the male and female 

 occupy during the coitus, it is almost impossible to be absolutely certain whether the 

 narrow end of the capsule, which lies between the mandibles of the male, is applied a 

 little more or a little less to the side ; but in the instances of //. hirsntus which I have 

 watched it has appeared to me, as far as I could judge, that the mandibles were too 

 far at the side for the vagina, and seemed much more like being at the mouth of the 

 ringed tubes. 



I have not even found spermatocysts or spermatozoa in the ringed tubes, but 

 neither have I ever found them in the vagina or oviduct of any species possessing the 

 sacculus or ringed tubes, although I find them abundantly in those situations in species 

 which have not the ringed tubes. 



It must be clearly borne in mind that in such species as G. crassns, G. terriMlis, &c, 



45* 



