TIE INTELLECTUAL OBSERVED 



DECEMBER, 1865. 



SHIELD-BEARING CRUSTACEA (Recent and Fossil). 



BY HENRY WOODWARD, E.G.S., F.Z.S., 

 Of the British Museum. 



(With a Coloured Plate.) 



To discover tlie structure and investigate the anatomy of 

 organic beings is the life-task of every true naturalist. And 

 not only must he study the living forms of to-day , but also 

 those which existed in the bygone ages of geologic time. For 

 palseontology not only makes us acquainted with forms which 

 have now entirely disappeared, but also with others which 

 belong to still existing groups; all of which, however, fill 

 up, and, as it were, fit into, vacant places in the series, and 

 are needed, before we can arrive at a complete conspectus of 

 aDy one class. 



Among the diverse types of living forms, few, if any, exceed 

 the Crustacea in interest ; for they claim an antiquity so remote, 

 and are marked by characters so varied, and yet so typical, 

 that they are readily distinguished from all other classes, both 

 in a fossil as well as in a recent state.* 



The Crustacea belong to the sub -kingdom Articulata, the 

 first class of which includes the Insects ; the second the Arach- 

 nides (spiders, scorpions, etc.) ; the third the Crustacea (crabs, 

 lobsters, etc.) ; the fourth, Worms ; and lastly, the Internal 

 Worms (Eiitozoa). 



Great as may at first sight appear to be the difference 

 between the perfect insect, endowed with powers of aerial 

 locomotion, and the worm, yet it will be remembered that in 



* Even the anomalous Cirripedia, the " barnacles" and " acorn-shells," show 

 in their adult condition, on close examination, evidence of crab-character that can 

 only be observed in this class, whilst in their larval stages they pass through 

 similar metamorphoses to those of the higher orders. 



VOL. VIII. — NO. V. Y 



