8 MEMOIR I. 



microscope, and found to his surprise, that the anterior 

 portion of the animal had changed its form, and on the 

 fourth day it had acquired the appearance represented 

 Plate I. fig. 1, 6, so that together with the other individuals 

 he had taken, it seemed to have experienced a complete 

 metamorphosis ; under this new form, the dorsal spine had 

 disappeared, the front spine had become comparatively 

 small, the antennae were rendered conspicuous, the feet 

 and eyes were apparently more developed, and the tail had 

 changed from forked to spatulate, fringed by a row of 

 thirteen short spines. It will readily occur to the reader, 

 that observations made in this way, upon aquatic animals 

 at once so minute and so transparent, require the greatest 

 cane and circumspection to insure any positive result; from 

 much experience, the author is led to suppose, that Slabber 

 lost his Zoeas in changing the sea water, and that the new 

 form came from the added portion, a circumstance rendered 

 more probable, by his having met with both these types at 

 the same season of the year. 



It was during the spring of 1822, that the author to his 

 great surprise, first met with Zoeas in the harbour of 

 Cove, and that in considerable abundance ; the year fol- 

 lowing at the same season, one of considerable size 

 occurred, amongst a great number of smaller ones, and 

 jvidging it full grown, (PlatcII. fig.l, 2,) and a fit subject to 

 keep for the purpose of witnessing the metamorphosis 

 observed by Slabber, it was daily supplied with fresh sea 

 water in the most careful manner, from May 14, until the 

 15th June, when it died in the act of changing its skin, 

 and of passing into a new form, but one by no means 

 similar to that expected, as appears evidently by its disen- 

 gaged members (fig. 11.) which are changed in number, as 

 well as in form, and now, correspond with those of the 

 Decapoda, (Crabs, &c.) viz. five pair, the anterior of them 

 furnished with a large claAv or pincer : the metamorphosis 

 not having been completed, prevented any knowledge 



