Ill 



ever, crabs and lobsters are both sold by weight ; and the small 

 crabs on the north-east coast are also sold by weight. 



Crabs and lobsters form the most important species of Natural history 

 the stalk-eyed Crustacea. The principal crab eaten in this o f crabs and 

 country is the Cancer Paguvus. Only one species of lobster — 

 the Homarus Vulgaris — is found off the coasts of Great Britain. 

 In using the word " crab/' then, we shall always in this report 

 refer to the Cancer Pagurus. The word " lobster," in the follow- 

 ing pages, similarly refers to the Homarus Vulgaris alone. 



Till a comparatively very recent period, little was known of 

 the natural history of the numerous Crustacea. No naturalist 

 had made it his special business to observe the metamorphoses 

 to which these creatures are liable. Various opinions were en- 

 tertained by the highest authorities on the subject ; and the 

 minute Zoea, which have since been proved to be the young 

 of the different kinds of Crustacea, were commonly classed as 

 distinct forms of life. About the year 1770, a Dutch natu- 

 ralist, Slabber, discovered that one of these Zoea, which he 

 kept in captivity for the purpose of observation, entirety changed 

 its appearance on the third and fourth days of its detention. 

 The metamorphosis was so complete that some of Slabber's 

 critics doubted whether, in renewing the salt water, he had 

 not accidentally released his original captive, and imprisoned 

 a new one. Subsequent inquiries leave little room, however, for 

 disputing the accuracy of Slabber's observations. In 1823 Mr. 

 Vaughan Thompson " established the remarkable fact that those 

 " anomalous forms which constituted the genus Zoea of Bosc are 

 " nothing more than the early or larvae condition of the higher 

 " Crustacea." Mr. Thompson succeeded in keeping one of the 

 larger Zoea, and in watching the same metamorphosis which 

 Slabber had observed. He succeeded in hatching the ova of the 

 common crab, and in establishing the fact that the produce " were 

 " true Zoeas" The late Mr. Couch (whose elaborate researches 

 into the history of almost every form of ocean life have made his 

 name a household word among ichthyologists) repeated Mr. 

 Thompson's experiments. He also succeeded in hatching out the 

 ova of the Cancer Pagurus, and in watching the young through 

 two distinct metamorphoses. 



The reader, who may wish to pursue the subject further, will 

 find illustrations of the earlier stages both of the lobster and 

 the crab in the interesting introduction to Bell's History of the 

 British Stalk-eyed Crustacea,"* and in Mr. Spence Bate's paper in 

 the Philosophical Transactions. We may take this opportunity 

 of saying that we are much indebted to these works for the 

 information with which we have been enabled to preface this 

 report. In a public report of this description, however, it would 

 be" impossible to follow out the subject more minutely ; but one 

 of us, Mr. Buckand, has, in an appendix,! given detailed results 



Loudon, Van Voorst & Co. f Joint Appendix No. II. 



