415 
Catalogue of British Fossil Crustacea. 
described, and in Bokemia 350 species have been named and 
figured by Barrande alone. The great Paradoxides Davidis 
measures nearly two feet in lengtk. As tkis group ascends in time, 
we find tkose extravagantly ornamented and spinöse forms, suck as 
Paradoxides and Acidaspis, disappear; and only tkree genera sur- 
vive in tlie Carboniferous, small in size, and very regulär and neat 
in form, especially tke genus Griffithides. 
Amphipoda. — The Amphipoda has one representative in tke Upper 
Silurian (tke Necrogammarus Salweyi, H. Woodw.) ; it is represented 
by Gampsonyx in the Coal of Bhenish Prussia ; and by the genus 
Prosoponiscus in the Permian of Durkam. Otker (Secondary) species 
occur in Bavaria, etc. Tke living genera of Amphipoda are 
abundant botk in marine and freskwater, and some species are even 
terrestrial in tkeir kabits. 
Xiphosura. — Tke earliest representative of the King-Crabs known 
is the Neolimulus falcatus, H. Woodw., from tke Upper Silurian of 
Lanarkskire ; several species are met witk in tke Coal-measures, and 
are very widely distributed. Tke genus is represented largely in 
the Oolite of Bavaria, and is also found living to-day in botk tke Old 
and New World. 
Eurypterida. — Tke Eurypterida, like tke Trilobita, are an 
extinct Order. Tkey were represented in Devonian and Silurian 
times by genera, wkick attained a lengtk of from 5 to 6 feet. Tkey 
are nearly related to tke King-Crabs in structure, but differed in 
tkeir development as do tke Lobsters from tke Crabs at the present 
day : the Xiphosura representing tke Brachyura, and tke Eury- 
pterida tke Macrura. 
Phyllopoda. — Tke PkyMopoda are represented from tke Middle 
Cambrian to tke Tertiary period by many genera. Large extinct 
forms, closely resembling tke little modern Nebalia bipes, were 
abundant in the Upper Silurian of Ludlow and Lanark. Tkey are 
represented to-day by species in freskwater, brackisk water, salt 
water, and bigkly saline salterns and lakes. 
Ostracoda. — Tke Bivalved Entomostraca included in tkis Order 
are largely represented througkout tke entire series of stratified 
rocks, from tke Lower Cambrian to tke present day; tkey are equally 
well represented in a recent state. Tkey not unfrequently (as in 
tke Cypris shales of tke Wealden) make up entire strata witk tkeir 
accumulated bivalved carapaces. 
Cirripedia. (a.) Balanid^:. — Tke oldest fossil sessile Cirripede 
is tke Pyrgoma cretacea, H. Woodw., from tke Upper Ckalk of 
Norwich. 
(b.) Lepadidje. — Tke oldest known pedunculated Cirripede is tke 
Turrilepas Wrightii, H. Woodw., from tke Upper Silurian of Dudley. 
None have been met witk lower tlian tke Lias except Turrilepas ; 
but from the Lias upwards, pedunculated forms are well represented. 
Tke grouj) is abundant and cosmopolitan in all tke seas of tke 
world, parasitic on all objects, living and dead. 
Tke subjoined Table gives tke number of genera, species, and 
varieties belonging to eack order, and suborder in tke dass Crustacea. 
