Order 4. LCEMODIPODA. 429 



the order ls»jpoda), namely, the Crevettiiies and the llyperines, the former divided into tlie saltatoiial 

 and amhulatory species. Some new genera were added, especially in the singular family of the llyperines. 

 Pterygocera, Latr., and some other genera, he considers not sufficiently studied, and consequently of 

 douhtful character and situation. Apseudes, lone, Anceus, and Pranha, he also regards as isopodous. 

 Various additional genera have also been established by M. Guerin de Meneville, in the Mayasin de 

 Zooloffie, especially amongst the Hyperines, and which are accompanied by figures and generic details. 

 Dr. Templeton has described some curious minute species from Mauritius, in the Transactions of the 

 Entomological Society. Still more recently I have received from M. Kroyer, the Danish naturalUt, a 

 memoir upon the Amphipoda of Greenland, pubhshed in the last part of the Copenhagen Transactions. 

 Rathke has described many new species, and some new genera from the Caspian Sea, in the last volume 

 of the Petersburg Memoirs, and Professor Owen has described some interesting species brought home in 

 one of the late Polar expeditions. One of the most remarkable of the subgenera established, is that of 

 Orio of A. Cocco, described in the Giornali di Scienze, Sfc, ;per la Sicilia, for November 1 833, which has 

 been overlooked by Crustaceologists, and in which the maxillary palpi are exceedingly slender, as long 

 as the body, and 4-jointed.] 



THE FOURTH ORDER OF CRUSTACEA, 



LCEMODIPODA,— 



Comprises the only Malacostraca with sessile eyes which have not distinct branohire attached 

 at the extremity of the body, which are nearly destitute of a tail, tiie hmd pair of legs being 

 attached either at the extremit)' of the body or to a segment, followed by one or two very 

 small joints. They are also the only spi-cies in which the two fore-legs, which conespond 

 with the second foot-jaws, form part of the head. 



All the species have four setaceous antennae, implanted on a peduncle of three joints ; 

 mandibles destitute of palpi ; a vesicular body at the base of at least four of the pairs of legs, 

 commencing with the second or third pair, including those of the head. The body, generally 

 filiform or linear, is compo»ed (including the head) of eight or nme segments, with several 

 small appendages in the form of tubercles at its posterior and mfcrior extremity. The legs 

 are terminated by a strong hook; the four anterior, of which the second piiir is the largest, are 

 always terminated by a monodactyle claw. In some, the four following are more slender, 

 with fewer articulations, without a terminal hook, or are rudimental and in no manner fitted 

 for the ordinary uses. 



The females carry their eggs beneath the secimd and third segments of the body, in a pouch 

 formed of scales closely applied against each other. 



All these Crustacea are marine. M. Savigny considers them as approaching the Pycno- 

 gonides, and as forming, together with them, the passage between the Crustacea and 

 Arachnida. In the first edition of this work, they formed part of the Isopodous order, namely, 

 the section Cystibranchiae. 



They may be considered as forming a single genus, for which, on account of its priority, the name of 



Cyamxjs (Latr.) — 

 should be retained. 



Some of these (forming a first section named Filiformia, Latr.) have the body long and very slender 

 or Unear, with the segments longitudinal ; the legs also long and very slender, and the terminal fila- 

 ment of the antenna; composed of minute joints. 



They are found amongst marine plants, creeping along in the same way as the Geometer or Looper- 

 caterpillars, bending themselves often back with great rapidity, and applying their antennae to various 

 parts of the body. In swimming they bend the two ends of the body downwards. 



