and the Embryology of Antolytus cornutus. 405 



EXPLANATION OF THK PLATES. 



Plate IX. 



{Autolytus cornutus — viale and female.) 



Fig. 1. — An adult female, full of eggs, seen from above, 

 the eggs are placed in all the rings on each side of the 

 alimentary canal (/) ; a, the middle tentacle of the head ; 

 a' and a", the left and right tentacle in advance of the 

 eyes b ; c, the small tentacular cirrus placed behind the 

 eyes on the lower side ; c', the large dorsal cirrus of the 

 second ring developed into a tentacular cirrus ; c'\ the 

 dorsal cirrus of the rings in which there are only one kind 

 of bristles ; d, the dorsal cirrus of the rings in which the 

 two kinds of bristles are found ; w, the mouth ; o, the 

 eggs ; /, the anterior part of the alimentary canal. 



Fig. 2. — The sac of a female in which the young 

 parent stocks of Autolytus cornutus are developed previous 

 to hatching. O shows this membrane and the young 

 parent stocks in one side of it. 



Fig. 3. — One of the feet of the rings provided with one 

 kind of bristles ; c, the dorsal cirrus ; /t, the tubercle from 

 which project the hooked bristles. 



Fig. 4. — One of the feet of the posterior rings provided 

 with two kinds of bristles, lettering as in fig. 3 ; A', the 

 tubercle from which project the thin, needle-shaped setae. 



Fig. 5. — A bristle from the upper bunch of setae. 



Fig. 6. — Bristle, with sickle-shaped hook, taken from the 

 lower bunch of bristles. 



Fig. 7. — The head of a male seen from above. Letters 

 as in fig. 8, PL XL, a'" being a small tentacular cirrus 

 placed at the base of the forked tentacles. 



Fig. 8. — Shows the shape of the dorsal cirri. 



Fig. 9. — Parent stock, with a male of Autolytus cornutus 

 attached, just ready to separate. The lettering of the male 

 ready to be separated is the same as before. Correspond- 



