414 Prof. S. Loven on the Development 0/ Me Chitons. 



round the clusters of eggs ; their form is more elongated than 

 when enclosed within the egg ; the fore-part exhibits not hing 

 but fine cilia, which probably existed previously, and the tuft of 

 filaments is extended at full length and occasionally vibrated, 

 although but slowly. There is nothing as yet to indicate the 

 Ckiton ; but the posterior part of the animal now begins to grow 

 more rapidly than the anterior (figs. 2, 3), which becomes more 

 conical ; and the lower part is specially characterized by the 

 separation of the back of the mantle by means of two furrows and 

 its division into joints, of which seven are distinguishable, and 

 through which some close granulations make their appearance as 



Fio;. 1. 



Development of {Chiton) Leptochiton cinereus 

 Fig. 2. ,/ Fig. 3 



Fig. 4. 



Fig. 5. 



Fig. 6, 



Embrj'o in the egg. 



Dorsal view of young Chiton, showing the commencement of the 

 divisions. 



Lateral view of the same. 



Dorsal view of young Chiton further advanced, with the seven irre- 

 gular plates deposited in the segments. 



The same from beneath, showing the foot, with the eyes on the sides 

 of the head. 



Dorsal view of a still older Chiton. 



the first rudiments of the shell. The anterior part is sprinkled 

 with pointed tubercles, which are also seen on the margins of the 

 mantle. The animal bends itself frequently ; it is still quite soft, 

 and can only swim ; but soon after this it begins to crawl (fig. 2). 

 By the circular indentation of the mantle on the under side. 



