410 Royal Society : — 



was supposed by all to be a portion of tl;o generative organs, though 

 they were not able to trace its connexion with the penis. It is a 

 large V-shaped tube, which lies transversely across the abdomen ; at 

 each end it dwindles into a very fine tube, which passes, on each 

 side, round the tracheal trunks close to the sjnracles, and then 

 the two, approaching one another, unite in the centre of the body and 

 fall into the long winding ductus ejaculatorius. Thus it will be seen 

 that the generative organs of the male Phalangidte are formed on 

 exactly the same type as those of the females. 



In Chelifer and Obisiian the ovary is a simple tube, on each side 

 of which the egg-follicles are produced. In each specimen there are 

 two sets of eggs in very diflfereut stages of development ; and it would 

 appear that thirty or forty come to maturity at once. In the early 

 part of the autumn I found four or five specimens with an egg-capsule 

 attached to the underside of the abdomen. These egg-capsules, how- 

 ever, only contained seventeen or eighteen eggs. Moreover, in these 

 specimens I found neither a testis nor an ordinary ovary, but a large 

 body consisting of about thirty follicles opening into a common cavity, 

 and full of oil-globules. The eggs in the egg-capsule were in several 

 cases undergoing segmentation. 



The males of Chetifer appear to be about as numerous as the 

 females. The testis consists of a median and two lateral tubes, which 

 are united together by three transverse branches. It is therefore 

 much like that of the true Scorpions. The spermatozoa in Obisium 

 have a small head and a long tail, while those of Chetifer are oval 

 bodies. These oval bodies maybe immature forms only, but I never 

 found any further stage of development in the spermatheca of the 

 female. 



The ovary of Petrobius consists of seven short egg-tubes ; each of 

 which in September contained three eggs, with more or less darkened 

 yelk, and about fifteen or twenty egg-germs in earlier stages. The 

 development of the eggs reminded me much of that which takes place 

 in the Orthoptera. 



It appears to be a pretty well established fact that, at least in many 

 animals, the Purkinjean vesicle is a modified ovarian cell, round which 

 the yelk is deposited. On the other hand, according to some eminent 

 naturalists, there are certain animals in which the ovarian cell becomes 

 the eyg, and its nucleus the Purkinjean vesicle. In this case we 

 should have two distinct classes of eggs, the Purkinjean vesicle in one 

 of which would be homologous with the whole egg in the other. I 

 have, however, given in my paper the reasons which induce me to doubt 

 whether these last observations are altogether correct. But even if 

 we may admit that no essential difference has as yet been proved to 

 exist in the eggs of animals, as far as regards the relations existing 

 between the Purkinjean vesicle and the original ovarian cell, it would 

 still seem that in the relations between the former and the yelk, two 

 very different ty})es of development must be recognized. 



In describing the so-called "winter-ova" oi Lacinularia socialis. 

 Prof. Huxley says (Micr. Journal, vol. i. p. 14), "It will be observed 

 that all these authors consider the winter-ova or epbippial ova and the 



