INTRODUCTION. xli 



veloped, and the tail had changed from forked to spatu- 

 late, fringed by a row of thirteen short spines." It would 

 certainly seem that this plain and simple statement, sup- 

 ported as it was in many respects by Mr. Thompson's 

 own subsequent observations, can scarcely justify the 

 conclusion to which that gentleman is led,* "that Slabber 

 lost his Zoea, in changing the sea water, and that the 

 new form came from the added portion." But the truth 

 of Slabber's statement, and, consequently, the evidence 

 of the correctness and originality of his discovery, are 

 very strongly proved by the almost absolute identity of 

 the second form of his animal with that of several species 

 subsequently observed ; and particularly of the ditch - 

 prawn, Pal&mon varians, as figured by Capt. Du Cane.f 



It was, however, from this observation of Slabber that 

 Mr. Thompson, in the year 1823, was induced to carry 

 out the investigation. In the spring of the previous year, 

 as he informs us, in the harbour of Cove, he first met with 

 Zoeas, and that in considerable abundance ; and " in the 

 year following, at the same season, one of considerable size 

 occurred, amongst a number of smaller ones, and, judging it 

 full grown, he considered it a fit subject to keep for the 

 purpose of witnessing the metamorphosis observed by 

 Slabber" &c. The metamorphosis was interrupted by 

 the death of the animal when in the act of undergoing 

 it ; but it had advanced sufficiently to show that the 

 animal belonged to the Brachyura, and the portion which 

 was observed, contained all the five feet on one side, 

 the anterior foot being furnished with a perfect claw ; 

 and it appears now more than probable that the form into 



* Zool. Researches, p. 8. t Ann. Nat. Hist. vol. ii. pi. 6. 



