296 MR. A. D. MICHAEL ON THE VARIATIONS IN THE 



reason I have not figured it. In G. terribiUs the genital plate (epigynum) of the female 

 is lifted hy the mandibles of the male and the capsule applied to the vagina ; in this 

 species the large spermatocysts are not ever found inside the female, only minute 

 spermatozoa in the recess of the vagina which exists in this species as in G. crassipes ; 

 the spermatocysts break up inside the capsule, which discharges only minute ovoid 

 spermatozoa imbedded in a thick viscid fluid. The outer walls of the spermatocysts are 

 left in the capsule or about it, and do not enter the female. In four cases of Gamasus 

 crassus killed during the coitus, the mandibles of the male were actually inside the 

 vagina of the female. This is a species very like Gamasus terribilis in general appear- 

 ance, but the female, although constructed on the G. crassipes type, has not merely the 

 domed recess in the vagina to act as a spermatheca ; it has a well-niarked, almost 

 globular spermatheca, joined to the vagina by a short chitinized tube with a narrow 

 opening (see fig. 42, spt). 



The mode of formation of the spermatic capsule in this species is really astonishing. 

 The lower or movable arm of the chela of the male mandible has a large foi-amen or 

 hole in it, shaped rather like a lemon-pip (fig. 19) ; the spermatic capsule passes right 

 through this hole and folds over. Each end is a sac, the anterior pyriform, the posterior 

 globular; neither sac would pass the hole, but they are joined by a long tubular 

 portion which does pass. It seems to me, therefore, that the capsule must be blown like 

 a bubble right through the hole ; the globular end of the capsule emerges last from the 

 genital aperture. Fig. 40 is drawn from a specimen killed in coitu and the mandibles 

 then freed from the vagina of the female ; the anterior sac of the capsule broken. 

 Fig. 41 shows the posterior end of the capsule emerging from the male genital aperture. 

 This species is one with filamentous spermatozoa. The mode in which the sperm is 

 applied to the female in other species will be discussed in dealing with the female 

 genital organs. 



I am of opinion that the more liquid contents of the capsule, other than the spermato- 

 cysts, are the produce of the great accessory glands of the male (gla, figs. 29, 31, 72) ; 

 but whether the wall of the capsule itself is the product of a separate gland or of a special 

 part of the main gland and is blown out like a soap-bubble by the rush of liquid and 

 other contents at the moment of formation, or perhaps it is a more apt simile to say as a 

 glass-blower blows a flask, or whether it is simply the hardening of the exterior part of 

 the general mass on exposure to the air, I have not been able to determine ; I incline to 

 the former hypothesis in consequence of the regular form which the capsule assumes and 

 its elasticity. If this be so, the formation of the narrow tubular portion of the capsule 

 in G. crassus would be easily understood ; after the anterior end of the flask has been 

 blown through the foramen in the movable arm of the chela, the mandible might, and 

 probably would be, quickly extruded ; the effect of this would be to draw out a long 

 tube of even diameter, as will be readily understood by anyone who has seen glass- 

 blowers draw barometer-tubes by fixiug one end of the molten flask and then moving 

 rapidly aAvay. 



