132 THE VOYAGE OF H.M.S. CHALLENGER. 



white egg-mass on one of his ovigerous legs, and about one hour later l)oth masses were 

 present. 



The female genital openings are a great deal larger than those of the male, and are of 

 an ovate shape, and, as a rule, oviducts are totally wanting. I only observed them in 

 the genus Colossendeis, where they have nearly the same course as the vasa deferentia. 

 Nearly in the middle of the second coxal joint of the two hind legs a lateral branch 

 arises from the ovarian ccecum, which passes through the joint. The interior of this 

 branch, which is the oviduct, is in immediate communication with the ovary, and during 

 the breeding season the eggs are found penetrating the branch. While the ovarian coeca 

 which penetrate the legs are lined only by connective tissue, the oviducts which 

 begin at the dorsal side of the second coxal joint and run along the wall of the joint till 

 they reach the opening on the ventral side, are lined by a coat of longitudinal muscle fibres. 

 The female genital opening in this species is small and rather triangular.^ 



From the end of the oviduct which reaches the opening, distinct muscle fibres 

 radiate, and are inserted round the opening on the inside of the chitinous wall of 

 the joint. A transverse section of the fourth joint of the leg of a female Colossendeis 

 leptorhynchus is figured in fig. 16, Plate XVI. ; m is the ovarian coecum which, as this 

 specimen is by no means mature, is only of small dimensions ; when in the breeding 

 season, the whole central cavity (which in the figure is represented as empty) is filled 

 with eggs ; it .swells to such an extent as to fill up almost the whole cavity of the leg, in 

 so far as this is not occupied by the intestinal coecum. As in the other species of 

 Colossendeis, the eggs are extremely numerous and small. Each ovarian egg has a 

 distinct germinal vesicle, which is placed almost exactly in the centre of the egg, and 

 has, as a rule, one distinct and very glittering germinal spot. Among the older eggs, 

 which are richly furnished with yelk, smaller ones are always observed whose protoplasm 

 is almost quite transparent. Each egg is surrounded by a very thin membrane, which is 

 a true " vitelline membrane " and adheres closely to the protoplasm of the egg. 



In the genus Nymphon, I have investigated the female genital organs of the follow- 

 ing species : — Nymphon hrevicmidatum, Miers ; N. hrachyrhynclms, Hoek ; N. robustum, 

 Bell ; N. longicoxa, Hoek ; and N. hamatum, Hoek. I never observed the ovary in 

 the body of these species, and always found at least a trace of it in the fourth joint of 

 the leg (thigh). 



When in an early stage of development, the ovary is placed against and at the dorsal 

 side of the intestinal ccecum which passes through the joint. While the ripe ova, which 

 are often very large (PI. XVI. fig. 7 I, ripe ovum of Nymphon hrevicaudatum, Miers), 

 have a thin vitelline meml^rane as in the ovum of Colossendeis ; younger ova have often the 



1 In this si^ecies, as I have mentioned already (p. 63), the genital openings, both in males and females, are present 

 only on the two hind legs ; at least in all the specimens at my disposition, 1 failed to oljserve them on the first two 

 pairs of legs. However, ovarian ccBca penetrate the first two pairs of legs as well as the two others. 



