BUB-CLAM B EUCRUSTACEA PHYLLOPODA 



Sub-Class B. EUCRUSTACEA. Kingsley. Crustacea prop 



Crustacea not /w ////// the /W// diridcil /'/// n<li<nt *<//// /////// /i//*o- .- 

 jil/fnrm, plumose, <>r laun-llnti' ijilh in < itlnr ////////' <// /?//<//. 



pairs of antemi<, ml ////// ///< ////*.////<// n/n/ ///<///<//7//rs /"/// /,/,///.,/ ///. ,\'"//y//i/.< 

 sta</6 either free-swimming or passed in //.- 



111 the Cnixfii'-Ki proper the appendages of tlir cep halot !. 



The first and second pairs arc prri>r;il and air known a- tli- . the 



third pair, placed at either side of the moutli, arc tin- tiniinlii,!<* . tin- fourth 

 and fifth pairs arc secondary jaws, called iniu-illm: The appciida^o liehind 

 these vary in character, MHIH- ln-in^ walking feet, while from one to three 

 pairs may be subsidiary to the maxillae in eating, in which case they are 

 called maxUlipeds. 



The Eiuyntsfacea are commonly divided into E ntomostraca and M<> 

 but the first of these groups is not a homogeneous assemblage ; it is rather a 

 division in which have been placed all forms not members of the .1A//I/-W/-,/,-,/. 

 the almost universal presence of a nauplius stage being its chief ditl'erentia! 

 character. The Eucrustacea are here divided into the super-orders /'///////*/</, 

 Ostracoda, Copepoda, Cirripedia, and Malacostraca. 



Super-Order 1. PHYLLOPODA. Latreille. 1 



Eucrustacea of elongated form, often with distinctly segmented bodies, M> 

 with flat shield-shaped or laterally compressed carapace. 



Under the Phyllopods are embraced very differently formed Crustaceans 

 of large and small size, living mostly in fresh water or salt marshes, and 

 possessing in common little else than the leaf-like form of leg and a uniform 

 developmental history. The segmentation of the body in higher forms 

 (Branchiopodd) is very distinct, but in the water-fleas (Cfadocerri) it is usuallv 

 quite incomplete. The number of body segments varies considerably 

 among different genera. In the strongly segmented forms the body i> 

 elongated and protected in front by a flat or shield-shaped dorsal cai apace 

 (Apus), or it is naked (Bmnchipus). In the Cladocera and /,'>///////</'/<, which 

 are enclosed in a bivalve shell, the body is laterally compressed, shortened. 

 and indistinctly segmented. The line of division between thorax and abdomen 



1 Literature : A. Recent Forms. 



Gnibe, E., Bemerkungen liber die Phyllopoden, etc. (Wiegmaun's Ardiiv fiir Natunrc^t li., XIX.. 

 XXXI.), 1853-65. Clans, C., Papers on Brauchipus, Apus, and Liinulus in AMiundl. (n^i-11-tli. 

 Wissensch. Gottingen, XVIIL, 1873 ; and Arbeit. Zool. In.st. \Vi,-n.. VI., 1886.- i: / /. .1 . 



Zur Naturgeschichte der Daphniden (Zeitschr. Wisseusch. Zool., XXVII., XXXIII.), 1876-80. 

 Lankester, E. R., Several papers on Liinulus, Apus, etc., iu Quart. Jouru. MUTDSC. Sor., XXI., 1881. 



Packard, A. S. t Monograph of the Phyllopod Crustacea of North America (12th Ann. Rrpt. t'.S. 

 Geogr. and Geol. Surv. Terr.), 1883. Jfansen, 11. ./., Phyllopoda and C'irriiHjdia. Plankton Ex- 

 pedition, 1895. 



B. Fossil Forms. 



Jones, T. R., On Fossil Estheriae and their Distribution (Quar. .lonrn. Geol. Soc., XIX.), 1863. 



Monograph of the Fossil Estheriae (Palaeontogr. Soc.), 186*2. 5th and 7th Repts. (.'.uniii. 

 British Assoc. Adv. Sci. on Fossil Pliyllopoda, 1887-89. Geol. Mag. Sept. 1890, %b. 1891, Dec. 

 1893, July 1894. Trans. Geol. Soc. Glasgow, IX., 1890. Clarke, J. M.. N-w Uvvonian Phyllnp...!- 

 (Amer. Journ. Sci., XXIII.), 1882. 11 //../., ;md r,, ,,-/-.. ./. M.. Palaeontology of New York, VII.. 

 p. 206, 1888. Bernard, H. M., Fossil Apodida.- (Nat ScL, XI.), 1897. Sch ,'];(. O, <n the 

 fossil Phyllopod genera Dipeltis and Protocaris (Proc. U. S. Nat. M<>. MX. . 1897. 



