220 POPULAR HISTOHY OF THE AQUARIUM. 



which was afterwards called " Zoea taiirus." He had taken 

 several specimens^ and placed one of them in sea-water for 

 the purpose of observation (an early Aquarium, by the bye) . 

 On the third day he found its movements becoming slower 

 and its colour paler. Subjecting it to the microscope, lie 

 found that the front part of the animal had changed its form, 

 and on the fourth day it had changed in every part. A large 

 spine on the carapace of the first form had disappeared in 

 the second ; and, together with other changes, the tail had 

 changed from a two-pronged fork to a broad flap, or spade. 

 The second form of this Zoea, as figured by Slabber, turns 

 out to correspond with that of several subsequently observed 

 species, the larvse of Valcemon. 



PALiEMON SERRATUS. (Plate XII.) 



Pew tenants of an Aquarium are equal in beauty to T.alcB- 

 mon seri'atus, or large Prawn. Even the boiled specimens, 

 as seen in the shops, are not without attraction ; but living, 

 they are indeed exquisite. The transparent body, with 

 zebra-like markings ; the delicate tinting and spotting ; the 

 elegant curved and serrated horn ; the brilliant, sparkling 

 eyes ; the gracefully curving and waving antennae ; the 

 slender legs, with their bright blue and yellow bands ; the 



