494 



FOSSIL PHYLLOPODS AND OSTRACODS. 



Fig. 113. Hymenocaris. 



Fig. 114. 

 Beyrichia 

 (enlarged). 



in the Lingula flags, Lingulocaris in the Tremadoc slates, Cariocaris 

 in the Arenig. Ceratiocaris ranges from the Tremadoc to the Car- 

 boniferous, Peltocaris from the Llandeilo to 

 the Wenlock, Dithyrocaris from the Lud- 

 low to the Carboniferous, Leaia is charac- 

 teristic of the British Carboniferous strata, 

 and the living genus Estlieria is found in 

 the Devonian and all newer strata, espe- 

 cially Triassic. 



The Ostracods are bivalve Crustacea of 

 small size, which are especially numerous 

 in the Primary rocks. Among the oldest 



types, Leperditia extends from the Harlech rocks to the Carboniferous. 

 Beyrichia ranges from the Arenig to the Coal, Primitia from the 

 Llandeilo to the Carboniferous, ^Echmina and Thlipsura 

 ^^ are "Wenlock ; Cytherellina is also Silurian. Moorea ranges 

 !||gj? from the Ludlow to the Lias, Entomis from the Silurian to 

 ^-"^ the Carboniferous, Entomidella is Menevian. The Carbon- 

 iferous period has many peculiar genera. Among them 

 are Carbonia, Cyprella, Cypridella, Cypridellina, Entomo- 

 conchus, Off a, Mhombina, and Sulcuna. But among other 

 genera which commence in the Carboniferous and survive to the 

 present time, may be mentioned Bairdia, Candona, Ct/pripina, Philo- 

 medes, and Polycope. Kirkbia is common to 

 the Carboniferous and Permian, Cytherideis 

 commences in the Permian, and still sur- 

 vives. Cythere is a living genus, which begins 

 in the Lias. Cypridea characterises the 

 Purbeck and Wealden. Cytheridea and 

 Cytherura begin in the Gault, and still sur- 

 vive ; Cytherella and Macrocypris are found 

 in the Chalk and Tertiary. The recent genus 

 Loxoconcha begins in the Crag. 

 The fossil Cirripedes belong to but few types. Turrilepas char- 

 acterises the Wenlock limestone ; Scalpellwn survives from the Lower 

 Greensand, Pollicipes from the Rhsetic beds ; Verruca survives from 

 the Chalk, Lauricula is peculiar to the Chalk, Coronula is found in 

 the Red Crag, while Balanus survives from the Headon beds of the 

 Isle of Wight. 1 



Vermes. The large group of worms is imperfectly represented in 

 the strata. Many are only known from their jaws, and they have 

 been for the most part described by Dr. G. J. Hinde in various 

 members of the Primary rocks. Other tubicolous types occur with 

 them, such as the Cambrian Conchicolites, Spirorbis, and Ortonia, 

 which range from the Cambrian to the Carboniferous. Cornulites, 

 Serpulites, and Trachyderma are Silurian. Genicularia is Jurassic. 

 The living Serpula commences in the Trias, Terebella in the Lias, 

 Ditrupa in the Cretaceous. Several errant worms are recogisable in 

 1 H. Woodward, Catalogue of Crustacea in the British Museum, 1876. 



Fig. 115. Cypridea. 



