6568 



Crustacea. 



unshapen substances here and there. Several of these were in the net 

 the first time we drew it in ; these were carefully transferred to a 

 tumbler full of clear sea-water collected to receive them. Scarcely 

 had the seemingly shapeless masses been placed in the small prison 

 than they dashed away in the full gambol of life's enjoyment, and 

 exhibited several forms that were formerly known to naturalists by the 

 name of Zoe. These were at one time thought to be mature animals, 

 adults of their kind, and described and named as such ; but a zealous 

 and close-observing naturalist, in this same month, a few years ago, on 

 his homeward course, after an unsuccessful day of search, entangled 

 a solitary specimen : he took it home, and carefully tended his new 

 acquaintance, supplied it with food and fresh water, and daily watched 

 its habits ; but all his care could not reproduce in the little prison the 

 conditions of the free and open ocean, and the poor thing, after a few 

 days, died. Had it been a starling or a man, we should say the poor 

 thing pined because it could " not get out as it was but a Zoe, we 

 think it had no sorrow or joy, no knowledge of the freedom it had lost, 

 no hope to desire its removal ; yet the free-swimming Zoe, that outlives 

 the lashing of the surges of the storm, that skims the surface of the 

 water when warm with the sun's rays, will not outlive a week of the 

 greatest care the naturalist can bestow upon it in confinement. 



Mr. Thomson's Zoe died within a week, but in dying told its 

 history. The Zoe was but a young crab. Here was a discovery : it 

 startled men of science all over the Continent. In Germany Rathke 

 took up the challenge, and traced the history of the development of 

 the Crustacea, as found in the freshwater crayfish (Astacus fluviatilis), 

 and declared that Thomson was wrong. The Academy of Paris re- 

 quested a deputation to investigate the subject, and sent MM. Audouin 

 and Milne-Edwards to the Island of Rhe, where they remained some 

 time in search of the truth, and declared that Mr. Thomson was wrong. 

 In our own country the discovery was not left to pass unquestioned : 

 Mr. Westvvood investigated the so-called metamorphosis in the deve- 

 lopment of the land-crabs of Jamaica, and Dr. Kirby, in his ' Bridge- 

 water Treatise,' refused to admit the correctness of Mr. Thomson's 

 observation. But while all these investigators were at work, Mr. Thom- 

 son was still pursuing his course of observations, and found that 

 another genus of Crustacea, that which Dr. Leach had named Mega- 

 lopa, was also a young form of the common crab, and singularly enough 

 the same volume of the * Philosophical Transactions' which contains 

 Mr. Westwood's refutation of the possibility of the Zoe being the 

 young of a crab contains also Mr. Thomson's discovery that the Zoe 



