THE MALAYAN SPKCIKS OF ONYCHOPHORA. 79 



All the figures on Plate 5 were carefully drawn by Mr. P, J. Bayzaud 

 under tiie author's supervision. The remaining figures were drawn by the 

 author himself with the aid of the camera lucida. 



PLATE 5. 



Fig. 1 (X 120). — This figure represents a young embryo of Eoperipalus 

 weldoni. The blastopore is slit-like, and possesses irregular outlines. 

 Externally there is no sign of segmentation. The actual length of the 

 embryo was I'l mm. 



Fig. 2 (X 120). — This figure represents a young embryo of Eoperi))atus 

 weldoni. The blastopore has been divided into two portions by the fusion 

 of the lips. The anterior portion is small and slit-like, and, owing to the 

 external yolk, can only be seen in sections. The posterior portion is a big 

 hole with no very definite anterior lip, but the lateral and posterior lips are 

 considerably thickened and quite definite. The primitive groove and streak 

 have appeared, and two somites of the body are externally visible. The 

 actual length of the embryo was '9 mm. 



Fig. 3 (x 120). — This figure represents a young embryo of Eoperipatus 

 weldoni. The rudiments of nearly all the appendages are externally visible. 

 The antennae have three rings, but no other appendage is ringed. The actual 

 length of the embryo in its folded condition was 1'4 mm. 



Fig. 4(X 120). — This figure represents an older embryo than the one 

 shown in the preceding figure. The rings on the antenna; have multiplied. 

 The legs as well as the body-wall are already ringed. The lips are appearing, 

 and the oral papillae present a depression at their outer ends. The actual 

 length of the embryo in its folded condition was TS mm. 



Fig. .5 (x 27*5). — This figure represents an embryo which is considerably 

 older than the one shown in the previous figure. The elongation and the 

 increase in the number of rings on the antennae are well marked. The ring- 

 like markings on the body and the appendages are clearly visible. The 

 posterior end of the embryo exhibits a tendency to pass from the dorsal 

 asjjcct, a position occupied by it in the embryos shown in Figs. 3 and 4, and 

 to become situated at the side. The actual Ifngtli of the embryo in its 

 folded condition was 3'1 mm. 



Fig. 6 (X 10). — This figure represents an embryo still more advanced than 

 the one shown in the previous figure. The most marked change of form 

 that has taken place consists in the partial straightening of the posterior end 

 after slipping from the position occupied by it in the embryos shown in Figs. 

 3 and 4, a change which was just commencing in the embryo shown in Fig. 5. 

 The actual length of the embryo in its folded condition was 7 mm. 



Fig. 7 (x 5). — This figure represents an embryo in which the body is 

 still more straightened than the one shown in the previous figure is. Not 



