﻿PYCXOGOXIDA. 5- 



Fig. 27: The same, from below. 



The embryonal legs have now been thrown off, and llic development oi the imaginal fore 



limbs has begnn. 



a. a. Tlie palps; />./>. the o\-igerons legs. 



— 28: A palp (third larval stage) newly begnn. 



— 29: An ovigerons leg (third larval stage) newly begun. 



Tab. II. 



Fig. I — 7. Xiiniphon robii.sliun Hell. 



Fig. I : First beginning of the embrxo, lateral view. 



The enibr\'onal legs are seen as distinct swellings. 



— 2: Larva of the second stage, lateral view. 



The larva is still enclosed in its membranes (and egg-shell?), bnt the tnmk is already seg- 

 mented, and the foremost pair of ambulatory legs are prett\' long. 



(7. The chelifori ; /'. the first embryonal leg enclosed by a dermal sheath ; c. the second em- 

 br\onal leg; (/. the proboscis; f. the first pair of ambulatory legs. 



— 3 : The proboscis, somewhat more enlarged, lateral view. 



Four cast-off sloughs of the proboscis are seen to be h'ing one within the other, with the 

 corresponding walls of the intestinal canal arranged in the same wav. 



— 4: Larva of the second stage, lateral \-iew. 



This phase is older than that of fig. 2 it having got the b}'ssus-threads; the second pair of 

 ambulator)- legs are also long, and the first pair distincth- articulated; on the other hand 

 onl\- the two foremost segments of the trunk have been constricted, and the two hindmost 

 pairs of ambulatory legs scarceh' begun. 

 /. The second ambulator\' leg. The other letters as in fig. 2. 



— 5: Free larva of the second stage, lateral ^■iew. 



A still older phase than fig. 4; nevertheless the last pair of ambulatory legs have not \et 

 been fully developed, but the larva is free of the egg-shell and the membranes. 



— 6: The same, from Iselow. 



The letters as in the preceding figures. 



— 7: Larva of the third stage, dorsal view. 



The embr\-onal legs and the byssus-threads are thrown off, but the newl\' begun imaginal 

 fore limbs ha\-e appeared. Of the ambulatory legs only one leg of the foremost pair has 

 been kept. 

 (/. f/. The chelifori; />. /k the palps; r. r. the beginning of the o\-igerous legs. 



Fig. 8 — 12. Nijinj>h(>n nuicroiijix G. ( ). vSars. 



Fig. 8: Larva of the first stage, dorsal view. 



Tile embr\onal legs and the proboscis are hidden by the trunk. 

 (/.a. The chelifori; {/.' ti'. the ducts of the byssus-giand.s. 

 — 9: The same, from below. 



r/.f/. The chelifori; /r'.t/'. the ducts of the liwssus-glands; />./>. the first pair of embryonal legs; 

 r. c. the second pair of eml)r\oiKd legs; (/. the pr()l)oscis; r. connnon ganglionic mass for the 

 embryonal legs. 



9' 



