PLATE X. 



Arctus tuberculatum (p. 70). 

 Fig. 1 . Lateral view ; natural size. 

 ,, 2. Dorsal view ; enlarged three times. 

 ,, lo $ . Fifth pair of pereiopoda of the male. 

 ,, lo?. Fifth pair of pereiopoda of the female. 



Arctus immaturus (p. 71). 

 „ 3. Dorsal aspect of a specimen ; enlarged four times. 

 ,, 3". Ventral aspect of pereion. 



Arctus pygwueus (p. 73). 

 „ 4$. Dorsal aspect of a female; enlarged four and a half times. 

 ,, 4c. Second antenna. 



,, 4y. Third pleopod and stylamlilvs: the latter detached and magnified. 

 ,, 4r. Brephalos; extracted from the ovum. 



