26 MB. M. I/AUEIE ON THE 



behind the large oval foramen lies a small subcircular one, through 

 which the posterior median diverticulum of the gut passes, and a 

 third pair of processes is given off at about the level of the front 

 of this circular foramen. Behind this second foramen the ento- 

 sternite is a solid plate. At first it narrows somewhat, but soon 

 expands again and runs out into the fourth and last pair of 

 processes. This entosternite is more complicated than is usual 

 in Arachnids, and this is probably to be correlated with the 

 greater development of the thorax and its appendages. The 

 processes into which it is drawn out serve for the attachment of 

 muscles. The first pair of processes has muscles from it to the 

 large second pair of appendages, while the other three serve for 

 the muscles of the three walking-legs, the thin third pair of 

 appendages being without any special process. 



The nervous si/stem is almost entirely concentrated in the 

 thorax. The cerebral ganglia are small oval structures placed 

 far back in the thorax (PL III. fig. 4) and giving rise to two pairs 

 of optic nerves. The far back position of these structures is due 

 to the large chelicerse which, when drawn in, occupy almost the 

 whole of the region in front of the brain. The three processes 

 from the epistoma, of which mention has been made, also reach 

 as far as the brain. The thoracic ganglion (fig. 5) is subtrian- 

 gular in form, and gives rise to the nerves for the greater part of 

 the body. The origin of the nerves to the first two appendages 

 could not be clearly made out, as the front part of the ganglion 

 is somewhat entangled in chitinous processes which come in 

 from the floor of the thorax. The nerves to appendages iii. to 

 vi., however, are quite distinct, and the posterior end of the 

 ganglion finally gives off a paired nerve-cord, alongside of which 

 run a number of fine nerves, the course and distribution of 

 which I failed to trace. The nerve-cord runs straight back with- 

 out any ganglia till it reaches the ninth free segment, in which 

 there is a small oval ganglion lying on the top of the right stink- 

 sac (fig. 6). A nerve passes out laterally from each side of this 

 ganglion, and a pair pass also posteriorly into the tail. 



The reproductive organs have been recently described *, but as 

 the paper only gives two schematic figures it is not of much 

 assistance in dissecting out these parts. Both the specimens 

 which I dissected were males, and their reproductive organs 

 were disposed as follows: — The testes are a pair of straight 

 * Biol. Centralbl. ix. 



