A.G ;<-i:ards the general shape of the body, in tin' .ureater number of the 

 form* it is very -lender and more ui- less cylindrical, with m> very pronounced demar- 

 cation between the anterior and posterior divisions. In some cases, however, tin- 

 posterior division, including tin- la-t segment of the nietasome. appears abrupth 

 much narrower than the anterior, which may be more or less expanded. a-> in 

 the Cyclopoida, tor instance, in the genera J//wy>/wia, /'-< itilnttirlinlitts. lili/n. etc. 

 In BOme torms both the anterior and posterior divisions appeal' greatly expanded, 

 whereby the body acipiires a pronouncedly depressed, even leaf-like form, as in 

 the genera y.ini^. f'i Itiiiiniti. /' i '< > Iliiiiniii. In other cases, quite contrary to this, 

 the body is found to be highly compressed, for instance in the genus .|////////o///\ 



The cephalosome is generally coalesced with the 1st segment of the meta- 

 sorae, though in some lew forms a well-marked demarcation between them ma\ 

 be found to exist. The lateral parts of this section are more or less expanded, 

 being so deep in some forms, e. g. the genus I.itiii/i/x <lin. that they wholly include 

 between them tbe oral appendages. It projects in front in a more or less distinct, 

 generally lamellar rostrum, which in most cases is movably connected with the 

 cephalic shield. The 3 succeeding segments of the metasome are always well 

 defined, and are provided with more or less distinct epimeral plates. The last 

 segment of the metasome, as stated above, has always a very movable articulation 

 with the preceding segment, whereas it is firmly connected with the 1st segment 

 of the urosome. Its epimeral plates are generally obsolete, or at any rate much 

 smaller than on the preceding segments. The urosome is composed of 5 segments, 

 the first 2 of which, however, in the female are more or less completely coalesced, 

 though in some forms a distinct suture between them is seen dorsally. In the 

 male these 2 segments are always distinctly separated, and the 1st of them pro- 

 jects at the end, on each side of the ventral face, to a small setiferous process. 

 The caudal rami are in most cases short, and firmly connected with the last 

 caudal segment. Of the apical setae, as a rule, only the L? middle ones are well 

 developed, the others lieim: more or less rudimentary. A single eye is generally 

 present, though in some forms, esp,.ciall\ in those from deep water, no trace of 

 such an organ is to be found. 



The anterior antenna- are. as a rule, of inferior si/e and composed 

 of a limited number of articulations, ran-l\ (as in the -enus )f^/ihr/n ) ex- 

 eeding H in all. One of the articulations, -enerally the .",rd or Itli. exhibits 

 at the end anteriorly a projecting knob, to \\hich a slender sensory appen- 

 dage is attached, and the succredini: portion of the antenna is generally 

 abruptly narrowed, forming a well-defined terminal part. In the male both these 

 antenna- are pn-ln nsile. and often Breath swollen in their outer part. The 



