GLOSSARY

The main features of the external anatomy of a typical harpacticoid are given in Figs. 1-3 and Figs. 4-41 illustrate other general and special features. Further detail and an account of the internal anatomy is given by Lang (1948). The list that follows is a short glossary of the terms and abbreviations used in the key and figures.

Web-based (HTML) key abbreviations *:

(F)	—	Female
(FF)	—	Females
(M)	—	Male
(MM)	—	Males

* We use these alphabetic abbreviations in the HTML version (instead of the classical symbols for Venus and Mars) because several tested web browsers for reading HTML files cannot display these graphically.

Original abbreviations:

A.1	—	Antennule (or 1^st Antenna). This is usually modified into a prehensile grasping organ in the male.
A.2	—	Antenna (or 2^nd Antenna) (Figs. 8-9).
Abd.	—	Abdomen.
Abd.1-Abd.5	—	The five abdominal segments. In the female the first two are fused together; they remain separate in the male.
An.op.	—	Anal operculum.
Anal seg.	—	The last (5^th) abdominal segment.
Allobasis	—	The fused basis and 1^st endopod segment of the antenna of some species (Fig. 9).
Apophysis	—	A mucroniform process of the outer distal corner of a segment. Usually this is a feature only of the modified P.2 (or P.3) endopod in the male of some families (Fig. 41).
a.s.	—	Apical setae.
Basis	—	The third of the stem segments of biramous appendages (but see also Pre-coxa, Allobasis and Benp.)
Benp.	—	Basendopod; the fused coxa, basis and endopod of P.5. Normally the Benp. bears one seta on its outer side and a variable number of setae on the inner section, which is usually referred to as the “inner expansion of the Benp.” For the purpose of these keys it is only these inner setae which are counted as the “setae of the Benp.” (Figs. 34-35).
cph.	—	Cephalothorax; primitively this comprises the head and the first thoracic segment (which bears the Mxp.) but in most families the 2nd thoracic segment (which bears the P.1) is fused to the head also.
coxa	—	The second of the stem segments of biramous appendages (but see also pre-coxa).
cu.r.	—	Caudal ramus; the pair of rami are collectively termed the caudal furca.
endite	—	Accessory segments of the syncoxa of the Maxilla.
Enp.	—	Endopod.
Exp.	—	Exopod.
i.s.	—	Inner setae; the setae, or spines, on the inner border of the exopod and endopod.
Labrum	—	The upper lip of the mouth.
Md.	—	Mandible.
Mxl	—	Maxillule (or 1^st Maxilla).
Mx2	—	Maxilla (or 2^nd Maxilla).
Mxp.	—	Maxilliped.
o.s.	—	Outer setae; the setae, or spines, on the outer border of the exopod and endopod.
P.1-P.4	—	The four thoracic locomotor appendages (Fig. 21).
P.5	—	The fifth and last thoracic appendage; always non-locomotory and with a sexual function. Those of the male are often reduced (Figs. 34-35).
P.6	—	The first and only abdominal appendage. Except for a few species this is absent in the female and reduced to a small lappet in the male.
P.4 Exp.3	—	The segments of P.1-P.4 are referred to in this manner in the keys; this example refers to the third segment (counting from the proximal end) of the exopod of P.4.
Pre-coxa	—	The first of the stem segments of the biramous appendage. Often it has been completely lost, or indistinguishably fused with the coxa, but it is present in the Mandible and Maxillule.
R.	—	Rostrum.
seg.	—	Segment; in the keys this term is used both in its correct sense, i.e. for the actual metamere of the body, and in its colloquial sense, i.e. for the constituent parts of appendages which properly should be called podomeres.
seta	—	This term is properly applied to a slender hollow projection of the cuticle enclosing an epidermal cell or part of one. Its slender shape distinguishes it from a spine and its hollow nature, recognizable articulation with the cuticle and generally larger size distinguishes it from a setule or spinule. Although these are not perfect criteria for distinguishing between them it is sufficient for the present purpose. With a little practice the user of these keys should experience no difficulties as care has been taken to refer to setae and spines only where there is little possibility of confusing them with the smaller structures or, where this has not been possible, to include a cautionary note of explanation.
setule	—	see seta.
spine	—	see seta.
spinule	—	see seta.
Syncoxa	—	The fused pre-coxa and coxa of the Maxilla.
Th.1-Th.4	—	The four free thoracic segments, which bear the P.2-P.5.