INTERNAL ANATOMY OF THE GAMASIN^E. 319 



galeae of the same writer. Behind the oral tube is seen the bipilate organ (" Bauchtiister " of 

 Kramer, " labium " of Winkler, &c.) ; behind this, in the median line, the almost hexagonal 

 sternal plate ; then the genital plate with a membranous anterior edge, and a small crescentic 

 metapodic plate on each side of it posteriorly ; finally, the anal plate (inversely pyriform) . 

 The stigmal plates are along the edges of the anterior part of the body. 



Fig. 3. The same species : last two joints of one of the mandibles of the male seen from the outer side ; 

 x 350. The lowest lobe and the two smaller globular lobes of the movable arm of the chela 

 are less chitinized than the other portions. The working or cardinal portion of the movable 

 arm is sunk in the fixed arm, and is only shown, as though the latter were transparent, in 

 order to exhibit its unusual form and elliptical foramen. 



Fig. 4. The same species : chela of one of the mandibles of the female seen from the outer side ; x 350. 

 The two laminae on the under-edge of each arm of the chela are less chitinized than the rest of 

 the organ. The fixed arm of the chela in all Gamasid-mandibles is the upper arm. 



Fig. 5. (Near right lower corner.) The same species : epistome of the male seen from above ; x 350. It 

 is very hyaline, but the basal triangle is rather more chitinized than the remainder. The 

 radiating lines springing from this are markings, not hairs. 



Fig. 6. Haemogamasus nidi, sp. n. (page 314) : chela of one of the mandibles of the male from the outer 

 side; x 380. 



Fig. 7. The same species : epistome seen from above ; x 350. It is very hyaline ; the radiating lines 

 near the centre are markings, not hairs. 



Fig. 8. Hamogamasus hirsutus, ?, dorsal aspect ; x 45. This drawing is to show the course of the 

 alimentary canal and Malpighian vessels ; it is taken from a young, but mature, living specimen, 

 the internal organs showing through the dorsal surface in consequence of the transparency of 

 the cuticle. The spines and hairs are omitted for the sake of clearness ; the legs also are 

 omitted. The oral tube (rostrum) is in outline ; the epistome is seen between and above the 

 extruded mandibles ; the irregular-shaped plate of thin chitin on the dorsal surface is semi- 

 transparent, and varies in form in every specimen. The small ventriculus, with its great 

 anterior and upper posterior caeca, is dark (as in nature when the creature is recently fed) ; 

 the Malpighian vessels are almost white (as in nature when seen by reflected light) . The 

 cloaca is shown, looking globular near the centre of the posterior end, between the distal 

 terminations of the caeca. The striated part is the soft cuticle. 



Fig. 9. (Near centre of lower part of Plate.) The same species ; chela of one of the mandibles of the 

 male from the outer side ; x 650. The lobate proximal portion of the fixed arm is flat (a 

 blade) and is very hyaline. 



Fig. 10. The same species : epistome of female seen from above ; x 350. 



Fig. 1 1 . The same species : epistome of another female seen from the same direction and magnified to 

 the same extent, in order to show the variation in different specimens. Both this and fig. 10 

 are carefully made from actual examples. 



Fig. 12. Lalaps oribatoides, sp. n. (page 315), ?, dorsal aspect; x 65. The two conspicuous black 

 spots arise from the excretory organs showing through the cuticle. The mandibles are 

 retracted. 



Fig. 13. The same species: chela of one of the mandibles of the male seen from the outer side; 

 x 355. The sharp spine on the fixed arm of the chela is probably a poison-fang. 



Fig. 14. The same species : chela of one of the mandibles of the female seen from the outer side ; 

 x 300. 



Fig. 15. The same species: epistome of female seen from above; x 300. The organ is very hyaline, 

 but the sub-triangular space at the base is rather more chitinized than the rest. The Hues 

 running forward from it are markings, not hairs. 



