'I'HK MALAYAN SPECIES OF ONYCHOFHORA. 47 



cephalic flexure. The actu;il length of the embryo in its 

 folded condition was 17 mm. 



The eighth figure on PI. 5 illustrates the last stage in the 

 development. The embryo is fully extended and presents 

 nearly all the characters of the newly-born young. Even 

 the colour is not very different, and the great length of the 

 body is a most remai'kable feature. In this latter respect it 

 surpasses the embryos of the genus Peripatus by several 

 millimetres. It may be worthy of note that the embryo 

 under consideration, which is a male specimen taken out of 

 the uterus of Eoperipatus weldoni, is five millimetres 

 longer than one of the male specimens of E. horsti obtained 

 from a dead tree trunk. Consequently there must be a con- 

 siderable difference in length between the embryos of E. 

 weldoni and of E. horsti at the time of birth. 



This concludes what I have to say on the embryonic stages 

 of Eoperipatus weldoni, viewed externally. There is 

 nothing new or remarkable in the various phases of outward 

 form through which the embryo passes in the course of de- 

 velopment from the egg — heavily laden with yolk — to the 

 young just before birth. The early stages in the develop- 

 ment appear to be passed through very quicklj^ and the 

 changes which occur appear to consist in the development 

 and differentiation of parts at the expense of yolk stored up 

 in the egg, the actual increase in volume being very small. 

 It is not until the rudiments of all the most important organs 

 have been developed that any appreciable increase in size 

 takes place. Consequently the first five embryos in the 

 uterus, counting from the ovary, present the appearance of 

 being of the same size when examined through the uterine 

 wall. The sixth embryo, however, is considerably laro-er 

 than the fifth, the seventh than the sixth, and the difference 

 between any two successive embryos goes on increasing to 

 the end of the series. 



The uterus may contain as many as a dozen embi:yos, the 

 second, third, fourth, fifth, seventh, ninth, tenth, and twelfth of 

 which are respectively represented on PI. 5, and illustrate 

 corresponding stages in the development. 



