COPEPOD GENUS HEMICYCLOPS — GOODING 1G9 



segment the only ones completely ciliated but several with cilia near 

 tips. Almost all setae with thickening in transverse rings. Aesthetes 

 narrow and rather inconspicuous, with basally thickened walls. 



Last 3 segments of tetramerous antenna typically bent at right 

 angles to first and lying near mouth region. (Subsequent terminology 

 with reference to this position.) Fourth segment offset in fashion 

 typical of clausidiids; almost quadrate; bearing terminally on dorsal 

 side a seta, with long heavy cilia, in a notch on the outer edge 2 

 spinulose setae, and 4 curved setae inserted linearly along width of 

 distal border between the two groups. Two proximal of the 3 "comb 

 rows" of spinules on this segment difficult to see. Outer corner of 

 third segment produced distally for more than half length of fourth; 

 2 characteristically ornamented spines at its tip; a curved seta and 

 another shorter seta in recess between this projection and insertion of 

 fourth segment. Surface thickening of 5 curved setae on antenna 

 irregular from region of initial curvature to tip; the latter either 

 notched (in the longest 2) or finely toothed on the inner side. Other 

 ornamentation and armature of appendage as shown in figure 2d. 



Mouth region (fig. 2e) and adjoining appendages closely compacted 

 in typical poecilostome fashion, their arrangement very similar to that 

 of //. audralis (Nicholls, 1944, fig. 21) or purpureas (Sars, 1917, 

 pi. lxxxi, "Or. area"). Labrum protruding from ventral body surface; 

 posterior border straight, its median portion with 2 rows of small 

 denticles set one above the other. Each flange forming posterior 

 corner of labrum with 2 rows of larger denticles; upper row turning 

 dorsally (i.e., toward mouth) at its inner end. Sides of labrum nearest 

 mouth cavity flaring sharply away from a median "prow" which 

 overhangs mouth. Labium a flat rectangular surface delimited by 

 thickenings in ventral cxoskeleton of head region; its anterior half 

 beset with rows of denticles pointing toward mouth. Between latter 

 and labium is a square area, the roof of the mouth cavity, clothed in 

 cilia and rising medially into a bilobed prominence. Paragnaths 

 inserting laterally on roof of mouth cavity anterior to labial corners; 

 thick, comma-shaped flaps profusely ciliated; oriented nearly at right 

 angles to surface beneath, with tips approaching each other on midline. 



Mandible with strongly thickened triangular base. Body of 

 appendage curves toward midline, backwards and upward, fitting 

 under sides of labral "prow" so that tip lies in mouth cavity. Ter- 

 minal armature a heavy, curved element, a spinulose blade, and 2 

 setae with strong cilia; all articulated. Dorsal element dentate along 

 one edge, with an incompletely toothed ridge at an angle on anterior 

 side. 



Flaplike maxillule distally bilobed : smaller lobe with 3, larger 

 (outer) with 5 setae, majority strongly ciliated and with transverse 



