SCHIZOPODA. 463 



Fossil Genera Palaeocaris and Acanthotelson Meek and Worthen, 

 Coal Measures, Illinois, Gampsonyx Coal Measures, Saarbriick. 



Baihynella natans, a minute crustacean, not exceeding 1 mm. in length, 

 two specimens of which were obtained by Vejdovsky in well water in 

 Prague, appears to be allied to Anaspides. An account of its anatomy, 

 so far as a single ill-preserved specimen rendered it possible, is given by 

 Caiman (loc. cit.). There is no shield. The eight thoracic segments 

 appear to be distinct and they carry biramous appendages, each with a 

 single epipodial lobe. The uropods are well developed, and the most 

 anterior pleopods are present, but the intermediate pleopods are missing. 

 No trace of eyes was found. 



Order 2. SCHIZOPODA.* 



Small Malacostraca with a large and usually flexible cephalo- 

 thoracic shield, and with the eight pairs of generally biramous 

 thoracic legs of approximately similar form. The gills, when 

 present, form a single series and project freely. 



The name Schizopoda was introduced in 1817 by Latreille 

 for a group of his Decapoda Macrura containing the two genera 

 My sis and Nebalia. The latter was separated in 1829, but 

 during the next 50 years, as new species were discovered, many 

 forms besides those, now generally recognized as Schizopods were 

 temporarily contained in it, and subsequently placed elsewhere. 

 The Stomatopods and some of the lower ' Decapods were thus 

 included, as well as a number of larval forms of Decapods, at 



* C. Glaus, Unters. z. Er/orschung d. genealogischen Grundlage d. Crus- 

 taceensy stems, Wien, 1876. Id. Neue Beitrage z. Morphologie d. Crusta- 

 ceen, Arb. aus d. Zool. Inst. Wien, T. 6, 1886. Id. Zur Kenntniss der 

 Kreislaufsorgane d. Schizopoden u. Decapoden, Ibid., T. 5, 1884. G. O. 

 Sars, Hist. Nat. d. Crustacea d'eau douce de Norvege, Christiania, 1867. 

 Id. Carcinologiske Bidrag. til Norges Fauna. My aider, Christiania, 1870. 

 Id. Rep. on the Schizopoda collected by H.M.S. Challenger, 1885. E. van 

 Beneden, Recherches sur 1'embryogenie des Crustaces, II, Bull. Acad. 

 Belgique, 1869. E. Metschnikoff, Ueb. d. Naupliuszustand von Euphausia 

 Zeits. /. wiss. Zool., xxi, 1871. R. v. Willemoes-Suhm, On some Atlantic 

 Crustacea, Trans. Linn. Soc., 1875. J. Nusbaum, L'Embryologie de 

 Mysis Chamaeleo, Arch. Zool. exp., 1887. P. Butschinsky, Zur Entwickel- 

 ungsgeschichte d. Mysiden, Schriften d. neu-russ. Gesellsch. d. Naturforsch, 

 (Russ.), Odessa, 1890. R. S. Bergh, Beitr. z. Embryologie d. Crustaceen, 

 I, Zool. Jahrb. vi (1893). J. Wagner, Unt. lib. d. Entw. d. Arthropoden, 

 Arb. Nat. Ges. Petersburg, 1896. C. Chun, Atlantis, BibL Zool. xix, 1896. 

 W. T. Caiman, On the Classification of the Malacostraca, Ann. and Mag. 

 of Nat. Hist., ser. 7, vol. 13, 1904. E. W. L. Holt and W. M. Tattersall, 

 Schizopodous Crustacea from the North-East Atlantic Slope, Rept. on 

 the Sea and Inland Fisheries of Ireland, 1902-3, pt. II. No. IV, i. W. T. 

 Caiman, Note on a genus of Euphausid Crustacea, Ibid. No. IV, ii. 



