COPKPODA 



341 



'Jg. r).'{.'5 — f'alocdlanuH pavo (Whoeler), 



land coast, a widely sproad, pol;i<^^i(' species, soiueiiiiies so nl)un<lanl, lliat 

 the s(!;i is (colored ycdiow or icd, and ol" ij^icmI ecoiioiriie, itii{>orl,aM<'e 

 l)0('ans(; it forms nil inipoitaiif, soiiicc of food ol" lieniii^' and iriaeUercd, 

 as well as ot" I lie (Jreenland whale. 



C. minor Clans. Lotij4tli about 1 .8 iiini.; tliora.x 01*4 sej^mentH; fifth 

 pair of." I0J4S })irarnos(!; 

 first antenrnu; not as lon<;- 

 as tlie body: (Jnlf sti(;airi, 

 off New England, a wide- 

 ly spn^ad Kpeeies. 



2. Calocalanus 

 rjiesljroelit. Tliorax of 

 I'eniah; consists of ',i scj^- 

 inerits, tiio first somite 

 bein^^ fiise<l with the 

 head, and tlu; fourth with 

 the fifth somite; uhdo- 

 men of female of 2 or 3 sep^ments; abdomen of male of f) scf^raentfi; 

 caudal spirH!S very lon;^' and [)Iumos(!: .'{ sp(;ei(;s. 



C. pavo (Dana) (Fi^''. 5;}.'{). Abdomen of femah; of 2 segments; 

 caudal bristh\s symmetiieai, branched, an<l spr(!a(lin<^; len<j;tli 1 mm.; 

 body transparent and rciddisli : a trof>ical species which may be found in 

 the (iulf streairi off N(;w Knuhmd. 



Family 2. CENTROPAOIDAE.* 

 Body elonj^^'ate; first antennae very lon^', with 23 to 25 joints in the 

 female; the ri;i4lit one (sometimes the left) in th(; male beinj^ preiiensile; 

 second antc^nnaf; laru(; and hiramosc;; heart j)r(;s(!nt; first 4 pairs of le^s 

 biramose, the outer braiich beinjj;' 3-jointed, the inner branch 1 to 3- 

 jointed; fifth pair of I(;^s biramose, often modified for clas[jin^'; a Kin<j;le 

 e^'^^ sac [jresent: about 2'> j/enera, and 200 species; in salt and fn;sfi water. 



Key to the j,^enera of C'enlropagidae here described: 

 a, Marine animals. 

 />, First ant(Minao with 24 segments, 



c, Thorax of 5 segments 1 . (.'kntkopaoks 



6-2 Thorax of 4 so;,'ni(iits 2. Tkmoha 



/>2 First antennae with 2li s('j,'inents 3. Meiiudia 



«2 Both marin«! and fresh-water animals. 

 h, First antennae with 25 se{?ments; fifth fec^t hiramosr^ .. .4. Limnocalanuh 



h.^ First antenna*! with 24 segm<'nts; fifth feet uniramose r». Fckytkmoua 



(I;, Fi-esh-water animals ; first antennae with 2r» sei^ments, 



hi Fifth feet uniramose ; af)dornen asymmetrical (I. Fi'iseiiUKA 



h.^ Fifth fcrt biramose ; inner hraneli of first pair of feet 2-joint«'d. 



7. DlAPTOMUS 



♦ Seo "Tlie Nortli American Contropagidac," etc., by F. W. Schacht, Bull, of 111. 

 St. Lab., Vol. k>, [). 2li5, 1898. 



