La:MOL»IPODA. 429 



the order Isopoda), namely, the Crevettines and the Ilyperhics, the former divided into the saltatnnal 

 and and)u!atory species. Some new genera were added, esi)ecially in the singular family of the Ilyperines. 

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

 douhtful character and situation. Apseudes, lone, Anceiis, and Praniza, lie iilso regan's as isojiodous. 

 Various adilitional genera have also been estal)lished by M. Gnerin dc Meneville, in the Maynsiu de 

 Zooloyie, especially amongst the Ilyperines, 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 naturalist, a 

 memoir upon the Amphipoda of Greenland, published in the last part of the Copenhayen Transactions. 

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

 of the Pctershury 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 Sicilla, for November 1 833, whicli has 

 been overlooked l)y 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 hranchirc attached 

 at the extremity of the body, which are nearly destitute of a tail, the hind pair of logs being 

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

 small joints. They are also the only species m which the two fore-legs, whicli correspond 

 with the second foot-jaws, form j)art of the head. 



All the species have four setaceous aiitennsc, implanted on a peduncle of tliree 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 composed (including the head) of eight or nine segments, with several 

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

 are terminated by a strong honk ; the four anterior, of which the second pair 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 riulimental and in no manner fitted 

 for the ordinary uses. 



The females carry their eggs beneath the second 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 

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

 tlie section Cystibranchise. 



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



Cyamus (Latr.) — 

 should be retained. 



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

 or linear, 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 m.irine plants, creeping along in the same way as the Geometer or Looper- 

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

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



