NO. 3567 LABIDOCERA JOLLAE GROUP—FLEMINGER 5 
divisible into three primary tagmata, the cephalosome, the metasome, 
and the urosome. ‘The cephalosome consists of the cephalic somites 
bearing the antennules (A1), the antennae (A2), the mandibles (Mnd), 
the maxillules (Mx;), and the maxillae (Mx:), and the first true 
thoracic somite bearing the maxillipeds (Mxp). The metasome con- 
tains the five thoracic somites (TI-V) that bear the swimming legs 
(P1—-5), the last pair (P5) at least being sexually modified. The 
cephalosome and metasome jointly make up the prosome, i.e., all 
body segments anterior to the major articulation between TV and 
the genital segment. The urosome begins with the genital segment 
and contains four or less abdominal segments, the last one being the 
anal (perianal) segment bearing the caudal rami. 
The swimming legs consist of two basal segments, B1 proximal and 
B2 distal, together referred to as the protopodite, and two distal rami, 
the lateral exopod (Re) and the medial endopod (Ri). The segments 
of the rami are numbered in sequence from proximal to distal joint; 
e.g., second segment of the exopod of the fourth pair of legs would be 
referred to as Re2 of P4. The larger articulating elements on the 
segments of appendages are lateral (Se), medial (Si), or terminal (St), 
and are numbered proximal to distal, a new sequence beginning with 
each segment. Spinules and hairs (cilia) also articulate or arise from 
sockets. Nonarticulating structures, or those imperfectly separated 
from the parent element by a weak line of constriction but lacking an 
apparent line of flexure, are treated as a general class of processes with 
appropriate descriptive adjectives to denote form. 
The genital pore or antrum (Fahrenbach, 1962) is a cuticular-lined 
depression on the sternum of the genital segment into which the ovi- 
ducts (gonopores) open. The gonopores are incompletely shielded 
by a genital plate articulating along its anterior margin and possibly 
free along its posterior margin. 
Dentition of the mandibular gnathobase appears to be a useful 
phylogenetic tool, at least for the higher taxa of calanoid copepods. 
Relationships have been noted between shape and arrangement of the 
teeth and the kind and condition of the food observed in gut analyses 
of a number of different species (Fleminger, 1956; Beklemishev, 1959; 
Anaraku and Omori, 1963). 
Giesbrecht (1892, pl. 8, figs. 4, 8, 11) did not propose a formal 
nomenclature but sometimes numbered the teeth in a ventral to 
dorsal sequence. Beklemishev (1959) has employed a similar system 
of letters and numbers. Interfamily homologies in dentition are not 
established, but an empirical system for Pontellidae has been derived 
from a survey of pontellid genera (Fleminger, unpubl.) and is used in 
the descriptions that follow. For the subfamily Eupontellinae, three 
groups of teeth can be distinguished. Group 1 consists of the two 
