642 ARTHROPODA SUB-KINGDOM vn 



Order 2. CLADOCBRA. Milne-Edwards. 



Phyllopods with bivalve shell which partially or entirely encloses the body ; antennae 

 large, forming swimming organs ; four pairs of leaf-like thoracic feet. 



These have not yet been recognised with certainty in the fossil state. Possibly, 

 however, Lynceites ornatus, Goldenberg, from the Carboniferous, belongs here. 



Super-Order 2. COPEPODA. Latreille. 



Body elongate, usually distinctly segmented, the anterior somites being fused, the 

 posterior thoracic ones free. Both pairs of antennae well developed ; four or five pairs 

 of Uramms thoracic feet. Abdomen short or long, without appendages except for a 

 long caudal pair. 



The Copepoda are without representatives in the fossil state. 



Super-Order 3. OSTRACODA. Latreille. 1 



Small, indistinctly segmented Crustacea completely enclosed in a horny or calcareous 

 bivalve shell. Only seven pairs of appendages present two of antennae, one of 

 mandibles, two of maxillae, and two pairs of thoracic feet. Abdomen short and 



As a rule only the bivalve shell of the Ostracoda is found fossil, and since 

 the classification is based principally upon characters presented by the 

 appendages, the relations of recent to fossil forms cannot be made out with 

 certainty, especially as the form and ornamentation of the shell are largely 

 independent of the internal organisation. 



The valves are closed by a sub-central adductor muscle, the attachment of 

 which is marked on their inner sides by a tubercle, pit, or a number of small 

 spots. The shell is compact in structure, commonly from 1 mm. to 4 mm. in 

 length, although sometimes exceeding 20 mm. The outer surface may be 



1 Literature : 



Bosquet, J., Description des Entomostraces fossiles de la craie de Maestricht (Mem. Soc. Roy. 

 Sci. Liege, IV.), 1847. Description des Entomostraces fossiles des terrains tertiares de la France et 

 de la Belgique (Mem. Couronn. Acad. Roy. Belg., XXIV.), 1850. Monographic des Crustaces 

 fossiles dn terrain cretace du Duche de Limburg (Mem. Commiss. Carte geol. Neerlande). Haarlem, 

 1854. Reuss, A. E., Die fossilen Entomostracen des osterreichen Tertiarbeckens (Haid. naturw. 

 AbhandL, III. Pt. 1), 1850. Die Foraminiferen und Entomostracen des Kreidemergels von Lemberg 

 (ibid. IV., Pt. 1), 1851. Jones, T. R., A Monograph of the Entomostraca of the Cretaceous Forma- 

 tion of England (Palaeont. Soc.), 1849. Idem, and Hinde, G. J., A Supplemental Monograph of 

 the Cretaceous Entomostraca of England and Ireland (ibid.}, 1890. Jones, T. R., A Monograph of 

 the Tertiary Entomostraca of England (ibid.), 1857. Idem, and Sherborn, C. D., A Supplemental 

 Monograph of the Tertiary Entomostraca of England (ibid.), 1889. Jones, T. R., and Kirkby, J. W., 

 Notes on Palaeozoic bivalved Entomostraca, Nos. 1-32 (Ann. Mag. Nat. Hist.), 1855-95. Eyger, 0., 

 Die Ostracoden der Miocanschichten bei Ortenburg (Neues Jahrb. p. 403), 1858. Speyer, 0. W. C., 

 Die fossilen Ostracoden aus den Casseler Tertiarbildungen (Cassel Jahresber., vol. XIII.), 1863. 

 Brady, O. S., Crosskey, H. W., and Robertson, D., A Monograph of the Post-Tertiary Entomostraca 

 of Scotland (Palaeont. Soc.), 1874. Jones, T. R., Kirkby, J. W., and Brady, G. S., A Monograph 

 of the British Fossil bivalved Entomostraca from the Carboniferous Formations (ibid.), 1874, 1884. 

 Jones, T. A., and Holl, H. B., Notes on Palaeozoic bivalved Entomostraca (Ann. Mag. Nat. Hist. 

 [4], III.), 1869. Brady, G. S., and Norman, A. M., A Monograph of the marine and fresh-water 

 Ostracoda of the North Atlantic, etc. (Sci. Trans. Roy. Dublin Soc., IV., V.), 1889-96. Lienenklaus, 

 E., Monographic der Ostracoden des nordwestdeutshen Tertiars (Zeitschr. deutsch. geol. Ges., XLVI.), 

 1894. Jones, T. R., and Kirkby, J. W., On Carboniferous Ostracoda from Ireland (Sci. Trans. Roy. 

 Dublin Soc., VI.), 1896. Ulrich, E. 0., The Lower Silurian Ostracoda of Minnesota (Geol. Minn., 

 III. Pt. 2, Palaeont.), 1897. Sherborn, C. D., The literature of fossil Ostracods (Nat. Sci. X.), 1897. 



