INTERNAL ANATOMY OF THE GAMASINJL 321 



Pig. 33. The anterior portion of the genital system, hut without the testis, of an adult male Lcelaps Icevis ; 



to show the two elliptical accessory glands (page 292) with the constriction at their points of 



discharge. A single spermatocyst is travelling down one vas deferens. This was so in the 



actual specimen. 

 Fig. 34. (Left middle.) Sagittal median section through the testis o{ Lcelaps Icevis, x 150 (page 292), 



showing the developmental history of the sperm-mother-cell and spermatozoa, so far as it takes 



place in the testis. 

 Fig. 35. (The lowest line.) This is a series of drawings, numhered consecutively in small figures 1 to 



11. It illustrates the history of the development of the sperm-mother-cells and spermatozoa 



in Gamasus crassus (page 293) ; all drawn, x 170. These are all taken from the testis of the 



male ; the latest stage is to the right, but those found in the female are usually even more 



filamentous. 

 Fig. 36. (Right lower corner.) Outline of the rostrum (oral tube) and sternum, &c, seen from below, 



of a male Hcemogamasus hirsutus killed in coitu in an early stage of the coitus ; showing the 



spermatic capsule still in the genital aperture of the male, and not yet full-sized nor containing 



spermatocysts ; x 70 (page 295) . 

 Fig. 37. Spermatic capsule of the same species at its largest size, x 70 ; taken from a male killed in 



coitu at the moment when the spermatic capsule is about to be removed from the genital 



opening of the male by the mandibles of the male ; it is now full of spermatocysts, &c. 

 Fig. 38. Rostrum, mandibles, &c., seen from the side, of a male of the same species killed in coitu, at 



the end of the coitus, after the contents of the spermatic capsule had been discharged and 



after it had contracted by its elasticity; x 145. The rostrum has been dissected out; the 



empty capsule is seen with its small end held between, and attached to, the two mandibles. 



The lower part of the rostrum is shown in optical section, in order to exhibit the pharynx and 



its musculation. 

 Fig. 39. Rostrum, mandibles, &c, seeu from the side, of a male Lcelaps cuneifer, killed in coitu, at the 



same stage of the coitus as the last figure; x 150 (page 295). The spermatic capsule is in a 



similar condition. 

 Fig. 40. One mandible, seen from the side, of a male Gamasus crassus killed in coitu ; x 110 (page 296). 



The greater part of the mandible and the whole spermatic capsule were inside the vagina of 



female, and were dissected out after death. The spermatic capsule is seen passing through the 



foramen in the movable arm of the chela of the male mandible. The anterior end of the 



capsule has been fractured and destroyed ; its contents have been discharged. 

 Fig. 41. Genital aperture of a male of the same species killed in coitu at the momeut when the spermatic 



capsule is about to leave the aperture, x 110, showing the mode in which the end of the 



spermatic capsule, which emerges last, is folded over. 

 Fig. 42. Spermatheca of the female of the same species ; x 100. It arises as a stalked diverticulum 



from the anterior end of the vagina, above and between the inner chitinized labia. 

 Fig. 43. (Left lower corner.) The whole genital system of an adult female Sejus togatus seen from 



above ; x 300. It shows the racemose form of the ovary, the paired oviducts, and azygous 



vagina, all resembling Uropoda (page 309). The large central sac is the spermatheca, from 



which proceed muscles which are omitted in this figure. 

 Fig. 44. (A little to the right.) The spermatheca of the same creature seen from the side ; X 100. 



This is to show the muscles attached to its hind and ventral surfaces. 

 Fig. 45. (Left top corner.) A group of ripe spermatozoa taken from the testis of an adult male Sejus 



togatus ; x 300. Those taken from spermatheca of the female are precisely similar. Compare 



these with the penultimate form in Gamasus crassus, fig. 35, io. 

 Fig. 46. (Right lower corner.) General view of the alimentary and genital systems of an adult female 

 SECOND SERIES. — ZOOLOGY, VOL. V. 47 



