Crustacea. 837 



Next in importance to the observation and record of facts, is the 

 composition of connected works in which the distinctive characters, 

 as well as the habits or economy, of every species belonging to a 

 given tribe, or family, are carefully recorded and compared. Such 

 works were by Scopoli, White, Kirby, and others, emphatically called 

 " Monographs ;" and may be regarded, when carefully executed, as 

 carrying out the study of Natural History to its acme of value and 

 usefulness. They are the gems — the treasures of Natural-History 

 literature. 



Mr. Bell's ' History of the Crustacea' is one of these monographs, 

 and perhaps no work was ever commenced under more favourable 

 circumstances. The subject is not merely one of great interest, but 

 possesses the very unusual advantage of novelty : for, notwithstanding 

 the labours of our eminent countrymen — Dr. Leach, in their classifi- 

 cation, and Mr. Thompson, in their economy and metamorphosis — 

 the Crustacea of Great Britain are less perfectly known than any 

 other class, the individuals constituting which are of equal magnitude 

 and importance. The fact of their residence in the sea has offered a 

 barrier to collecting them, which many have considered insuperable : 

 the large and fleshy bodies have also, in many cases, through want of 

 care in removal, become putrescent and offensive, and have thus 

 deterred others. The great space occupied by specimens in a cabinet 

 has also been considered objectionable, on the ground of expense. 

 The want of good figures, and detailed descriptions, has often been a 

 source of just complaint. Thus several causes, all of them capable 

 of being removed, or already undergoing removal, have operated 

 against the study of Crustacea becoming a favourite pursuit. 



It is not our intention to enter on a critique of this welcome pub- 

 lication, but rather to announce its commencement to our readers, 

 and to give it our cordial recommendation. When we say that it is 

 illustrated uniformly with the rest of the beautiful series of which it 

 forms a part, we shall say all that is needful on that point, while the 

 following extracts will give an idea of the value of the letter-press. 



The common crab {Cancer Pagurus). " It was in the month of 

 June, 1826, that Mr. J. V. Thompson had the good fortune to suc- 

 ceed in hatching the ova of the common crab, and thus, by perfect 

 and satisfactory observation, demonstrated the truth of the theory 

 which his investigation of Zoea had already suggested to his mind, 

 of the true metamorphosis of the Crustacea ; a discovery which may 

 rank amongst the most interesting and important that have been made 

 within the sphere of the sciences of observation, not only in the 



