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List of Entomostraca found in Berwickshire. By Mr WILLIAM 

 BAIRD, Surgeon. 



THE great Class CRUSTACEA is divided by naturalists into two gene- 

 ral sections, the Malacostraca and Enlomostraca. The greater number 

 of the animals of this second division arc contained within a regular 

 shell, and they have therefore received the name of Entomostraca, from 

 the two Greek words signifying " insects with a shell." Little atten- 

 tion has been paid by British naturalists to the history of those exceed- 

 ingly interesting little animals, and what we do know of them, we owe 

 almost solely to our continental neighbours. Baker, indeed, in his mi- 

 croscopical researches, has taken notice of several species, and given 

 plates of them, but he has done little to add to our information with re- 

 gard to their anatomy and economy generally. Joblot and Ledermuller, 

 in their works on microscopical objects, have given plates also of several 

 species ; whilst De Geer, Schaeffer, and several other celebrated conti- 

 nental naturalists of the last century, have added each a little to our 

 knowledge of them. Linnaeus included all that he knew in one genus 

 Monoculus (so called from their possessing only one eye), and gives de- 

 scriptions of nine species only. Otho Fridericus Muller is the first re- 

 gular historian of these animals who has done them justice. To him it 

 is that we owe the greater part perhaps of our knowledge with regard to 

 their economy ; to his labours we owe our acquaintance with so many 

 curious little creatures ; and to his eloquence is perhaps owing the further 

 researches and more detailed histories of succeeding naturalists. His 

 work on the Entomostraca, published in 1785, is one of the most inte- 

 resting memoirs in Natural History that we are acquainted with ; and 

 though it appears from later naturalists that he has fallen into many 

 errors, still it is the most complete and best history of the Entomostraca 

 that has ever been published. Since the time of Muller, much has been 

 done to add to our knowledge of these interesting animals ; and the me- 

 moirs of Jurine, father and son, Ramdohr, and M. Straus, contain the 

 most excellent and most minute histories of detached genera that can be 

 met with. Their researches have been conducted with the greatest zeal 

 and care, and their labours have been abundantly crowned with success, 

 their memoirs leaving little to be done by succeeding naturalists but to 

 add to the species. Hermann i tils), Daudebart de Ferussac, Adolphe 

 Brongniart, and other continental naturalists, have also given some ex- 

 cellent memoirs upon detached genera and species, whilst our own cele- 

 brated Leach is the only British naturalist we know that has paid any 

 attention to the history of the Entomostraca ; his labours, too, being chief- 

 ly directed to the parasitic animals of the division. It surely is not 

 from want of interest belonging to them, that the naturalists of this coun- 

 try have neglected the Entomostraca, for many of them are worthy of 



