ON ZOEA, 8^c. 9 



being- acquired of its general form, enough however lias 

 been gained to shew, that the distinctive characters of 

 Zoea, and of Slabbers changed Zoea, were entirely lost, 

 that the members, from being natatory and cleft (as shall 

 shortly be shown,) become simple, and adapted to crawling 

 only. On the 1st of May of the present year, (1827,) 

 another large Zoea was taken, and dying towards the 

 end of the month without having the requisite strength 

 to disengage itself from the exuvium, presented precisely 

 the same results with the former. 



The proof however might be deemed incomplete, had 

 not the author the good fortune to succeed in hatching the 

 ova of the common Crab (Cancer 2}agurusJ during the 

 month of June last, which presented exactly the appear- 

 ance of Zoea taurus, with the addition of lateral spines to 

 the corselet : the Crustacea Decapoda then, indisputably 

 undergo a met amor pilosis, a fact, which will form an epoch 

 in the history of this generally neglected tribe, and tend to 

 create an interest which may operate favorably in directing 

 more of the attention of Naturalists towards them. In 

 their first and tender stage, they are essentially and purely 

 natatory animals, and no doubt possessed of corresponding 

 habits, swimming about freely and without intermission 

 in search of appropriate food ; in their perfect state, the 

 greater number can no longer avail themselves of the 

 power of swimming, but are furnished with pincers and 

 feet almost solely adapted to crawling, so that they arc 

 now under the necessity of confining their excursions in 

 pursuit of prey within more narrow limits. This curious 

 piece of economy, explains what has ever appeared para- 

 doxical to naturalists, viz. the annual peregrinations of the 

 Land- Crabs to the sea side, which, although acknowledged 

 to be true by several competent observers, could never 

 before be satisfactorily accounted for. 



Having avoided going much into detail of the structure 

 of the Zoeas so imperfectly observed by the authors cited. 



