~~ 41 — 



(4) The Coxal-gland. — There is in Admetus, as 

 in all Arachnids, a so-called coxal-gland. I have found 

 it, like the authors already cited, Miss Pereyaslawzewa 

 excepted, at the base of the third extremity; I am also 

 able to prove its existence, if only as a rudiment, at 

 the base of the fourth extremity. This last atrophies 

 very soon. At this stage the coxal-gland consists of a 

 perfectly straight tube, running from the under surface 

 of the coxa inwards, and lying immediately on the surface 

 of the brain itself. It is easily distinguishable from the 

 brain by the lighter tinction of its nuclei. It is every- 

 where surrounded by connective tissue. Whether it is 

 still in open communication with the ccelom or no I am 

 not able to decide. The occurrence of the coxal-gland 

 at this stage in the fourth extremity as well as in the 

 third makes it appear probable that it was originally seg- 

 mental, as in scorpions, and it is likely that it would be 

 discoverable in every segment in earlier stages of growth. 



(5) The Nervous System and Sense-organs. — 

 The nervous system at this stage consists of the cerebral 

 ganglia and of the ventral ganglion-cord*, this last extends 

 far into the abdomen. 



Of sense-organs only the median eyes and the coxal 

 sense-organs have as yet made their appearance. 



The prse-oral part of the brain consists, as in Stage 

 III, of two distinct tracts, distinguishable by size, colour, 

 and number of nuclei. The more anterior part consists 

 of closely packed, small and darkly-stained nuclei, 

 averaging *0034 mm. in size. Nowhere in the rest of the 

 brain are the nuclei so small, so densely packed, or so 

 darkly stainable. We shall call this part of the brain the 

 accessory brain. In all other parts of the brain the nuclei 

 are less densely packed; they average '01 mm. in 

 diameter. The brains of adult Admetus also show the 

 same division. 



These two parts of the brain, following Laurie (31), 

 who has briefly referred to the difference, are also said 

 to be distinguishable in Scorpions. 



I am in a position to give more notes about the 



