NO. 3574 



COPEPOD CRUSTACEANS — LEWIS 



segments" or "free pedigerous segments" are used to designate those 

 thoracic segments that are not fused with the cephalon The term 

 "genital segment" is used, although with some question, to designate 

 the fused sixth and seventh thoracic segments (=fifth and sixth pe- 

 digerous segments) m the Caligidea (Caligoidea of Yamaguti 1963) 

 In the lernaeocerids, penneUids, and lernaeopodoids, the terms "ceph- 

 alothorax" and "trunk" are used. The term "cephalothorax" has 

 the same meaning as that given above, while the term "trunk" desig- 

 nates the region mimediately posterior to the cephalothorax. The term 

 ^ ovigerous" is used to indicate a female with egg strings, the term 

 nonovigerous" to indicate a female without egg strings even though 

 the genital segment (or trunk) may contam eggs. 



With three exceptions, the terminology applied to the appendages 

 and processes is the same as that in Lewis (1964a). Thus the term 

 antennules" refers to the first antennae and the term "antennae" 

 refers to the second. The term "mandibles" refers to the pair of ap- 

 pendages immediately adjacent to the mouth and normally projecting 

 into a "mouth cone" if it is present. The term "maxiUipeds" refers 

 to the modified pair of appendages on the first thoracic segment whUe 

 the sternal furca" is a bifurcate, posteroventrally directed projection 

 between and slightly posterior to the maxilliped bases of trebiids 

 euryphorids, and caligids. The term "thoracic legs" designates the 

 pair of semifohaceous or fohaceous appendages arising from some of 

 the thoracic segments posterior to the first or maxiUiped-bearino- seg- 

 ment, whOe the "caudal rami" are the pair of appendages at the 

 posterior end of the body. 



The three exceptions to the original termmology have arisen from 

 a recently completed study made by the author on the nature of the 

 maxillae m the Cahgidea (ms in preparation). It appears that the 

 setule- or seta-bearing node lateral to the mouth cone of this group 

 of cahgoids is the maxiUule, but it seems that the spine or plate imme- 

 diately behind this structure in the trebiids, eirgids, euryphorids, and 

 cahgids IS an accessory formation and not part of the maxiUule. ' The 

 name "maxiUule" is now given to the setule-bearing node (maxillary 

 palp of Yamaguti, 1963), while the term "postoral process" refers 

 only to the spine or plate hnmediately behmd the maxiUule. The 

 term "maxUlae" applies to the second pair of maxiUae with its asso- 

 ciated pair of openmgs to the maxUlary glands. The term "post- 

 antennal process" is used to designate the process-bearing nodules and 

 the spmelike projection, if present, situated lateral and sli-htly 

 posterior to the base of the antenna. 



To faciUtate the use of the thoracic leg tables, a hypothetical tho- 

 racic leg IS shown in figure 1, giving the various thoracic leg armature 



