1G4 CEUSTACEANS. 



the stump is shell, not flesh, unless it may be some small residuary frag- 

 ments, — and that, in this state, the stump may be called inorganic. 

 Thus the whole remains unaltered, until a perfected animal is revealed 

 to \-iew by the first exuviation. — Fig. 9. 



Let us quit this suljject meantime, for another no less interesting 

 to him who is absorbed in wonder by the steady and uniform govern- 

 ment of the universe. 



Perpetuation. — Until the latest period, nothing Avas known of what 

 merited the earliest observation, the continuance of this portion of the 

 animal world. 



Considerable obscurity still reigns over the propagation of the 

 Ci'ustaceans, or the numerous animals associated under this general 

 name. The species of all seem to Ije perpetuated by ova, whereof the 

 embryo of many thus escaping, has still to undergo such imjDortant 

 change or modification as may be compared to real metamorphosis. 



But there are others wherein the interest seems comprehended in 

 some shght development of additional parts. 



The sex of the Crab, male or female, which, in as far as I am aware, 

 cannot be distinguished by age, size, colour or proportions, is denoted 

 in this section of the race by the appearance of the thorax, breast-plate 

 or apron, which in both sexes is triangular. That of the male is longer 

 and narrower compared with the dimensions of the specimen, while that 

 of the female is larger and broader. 



These creatures begin to breed at a very early period, and continue 

 very long prolific. They multiply in extraordiuarj' numbers, and at all 

 seasons of the year. I have seen the Cnnccr manas laden with roe in the 

 depth of winter. 



This roe or spawn originates within the shell or carapace, where it 

 may be found in a soft and immature condition. "While advancing 

 farther it issues by one or two orifices under the apron, which is elevated 

 by its progressive discharge, and spreads innumerable clusters of ova to 

 the very edges. 



I'^lien the specimen, Plate XXXIV. fig. 5. reached the end of Octo- 

 ber, the discharging spawn continued raising the apron during ten weeks. 



