Anthessius — Illg 
343 
responds in rough essentials to the paratype, 
but the armature was incompletely represented. 
For the male, the third leg was represented as 
corresponding in rough essentials to the female, 
the fourth leg was illustrated so that the exopo- 
dite corresponds to what I found in the female 
paratype and serves to indicate a correction 
can be made in the illustration for the female. 
However the illustration of the endopodite does 
not represent the condition found in any An- 
thessius male I know of. This figure then is 
subject to question. The figures 55, 56, repre- 
senting the fifth leg of the male, do not agree. 
I was unable to reinvestigate the appendage. 
DESCRIPTION: Female (Figs. 1-11), body 
length 4 mm., greatest width 2 mm., based on 
Wilson’s original description. Body of rather 
generalized cyclopoid contours, but with most 
thoracic and abdominal segments distinct, so 
that regionalization is not emphatic. Cephalo- 
some a fused complex bearing appendages 
through first swimming legs and comprising .34 
of total body length, measured from apex of 
cephalosome to end of a caudal ramus. Segment 
of first legs not free, but strongly indicated by 
lateral indentations and surface grooves. Meta- 
some including segments of second through 
fourth legs, with general body articulation be- 
tween segments of legs 4 and 5. Urosome (Fig. 
1) a complex including segment of legs 5, 
genital segment and 3 additional abdominal 
segments, considering element bearing anal 
opening and supporting caudal rami as terminal 
segment. Urosome comprising .41 of total body 
length. Genital segment expanded laterally. 
Antennule (Fig. 2) essentially 7-segmented, 
but with complicated articulation and integu- 
mental modification between second and third 
segments, so as to suggest either coalescence or 
incipient separation of an additional minute 
segment. Approximate proportional lengths of 
segments, basal to distal: Segment I, 3; II, 6; 
III, 1; IV, 3.5; V, 2; VI, 1; VII, 1. Setae varying 
in length; count per segment indeterminable in 
available material. 
Antenna (Fig. 3) with segmental composi- 
tion much obscured by additional flexures, in- 
volving integumental folds, and torsions of one 
region of appendage on adjoining regions, but 
probably essentially 3 -segmented. Basal segment 
clear-cut, apical articulation transverse, no arma- 
ture determinable. Second segment with very 
complicated distal articulation, this proceeding 
diagonally across appendage; no armature de- 
terminable. Terminal segment with cuticularized 
ridges and folds and with very broad distal 
margin furnishing insertion for elaborately artic- 
ulated clawlike elements and setae. Details of 
armature indeterminable from available mate- 
rial. 
Mandible (Fig. 4) a flat plate, with very 
cuticularized anterior and posterior margins. 
Appendage terminating in long lashlike blade 
with complicated marginal ornamentation. Two 
most basal elements of ornamentation flat tooth- 
like structures, compound apically and articulat- 
ing with margin of appendage. Remainder of 
ornamentation a long row of graduated denticles. 
On anterior margin articulated a long lashlike 
auxiliary seta with conspicuous graduated row 
of cilia on outer margin. Between apical lash 
and auxiliary seta an articulated cuticular piece 
with some marginal ornamentation. 
Maxilla ( Fig. 5 ) with very long articulation 
with body surface, resulting in characteristic 
massive basal segment, on which articulates flat- 
tened apical segment with heavy cuticulariza- 
tion. Apex produced in sharp angle anteriorly 
with toothlike expansions of cuticle forming a 
medial saw-edge. Five marginal teeth, formed 
by flangelike protrusions of cuticle. Apex 
produced as short spinelike process. Inserted at 
base of angle of curvature of this segment and 
lying on its surface an articulated setule. 
Maxilliped (Fig. 6) fairly long, 2-segmented. 
Basal segment a little over half as long as distal. 
Terminal segment with apical spinelike process. 
Margins somewhat cuticularized. 
First legs (Fig. 7) with well-developed bi- 
merous protopodites, yoked by substantial inter- 
FlGS. 1-11: Anthessius hawaiiensis (Wilson). The scales accompanying certain figures represent 0.1 mm. 
Female: 1, urosome; 2, antennule; 3, base of antenna; 4, mandible (partial); 5, maxilla; 6, maxilliped; 7, first 
leg; 8, second leg; 9, third leg; 10, fourth leg; 11, fifth leg. 
