IOO COPEPODA 



than in the female; dorsally to the frontal organ the outline is first bulked; above this a concavity, 

 and beneath the frontal spine another proeminence adorned with about 10 transversely placed chitinous 

 lines, laterally somewhat convergent, are found. The comparative length of the first four abdominal 

 somites and the furca is 15, 34, 23, 23 and 14; the anal somite is, seen from above, almost completely 

 covered, and the furcal ramus is only a little longer than wide. 



The antennulae (text-fig. 25 g) extend about to the end of the second abdominal somite, but 

 not as in the female beyond the end of the abdomen. The segmentation from segm. 8—14 is difficult 

 to make out, partly because the articular membranes are rather indistinct and partly because a number 

 of faint transverse lines were seen between the real membranes ; it seems, however, that only the segm. 

 12 and 13 are really fused; the segments 20 and 21 are completely, and 24 — 25 only partly fused. The 

 number of "^Bstetasken" is like Giesbrecht's description of Aetidius (Taf. 14 fig. 13), but the segments 

 8 cog possess 4. The segments 11 — 13 bear two setae each, of which the proximal is the longer, and is 

 inserted in a small protuberance; the Sd of segments 14, 15, 16 and 17 are placed on small protuberances. 

 The posterior seta of segm. 23 'extends somewhat beyond the middle of segment 24. In the Re II of the 

 antennae no setae were observed. The mandibulae possess a large but soft manducatory part without 

 distinct teeth but with a short Sdi ; the Basp. 2 has an ovoid minutely granular area, and the third one 

 as well as Ri I has no setae; the setae of the Ri and Re are better developed than in the female. 

 The maxillulae are in main features like those of G. brevispinus (fig. 1 e) but the Basp. Ill seems 

 only to have a single delicate seta, and the Re only 10 setae. The maxillae and maxillipeds are scarcely 

 different from those of Gaidius. 



The pes I is more slender than in the female; the articular line between Re I — II is wanting 

 posteriorly; the Se Re II is represented by a very short delicate bristle; the glandular pore in the 

 outer margin of Re III, which is only indicated in the female, is well developed. The inner margin 

 of the second basipodite was found smooth not only in the fourth, but also in the third pair of legs. 

 The fifth pair of legs (PI. Ill figs 3 d — f) is in main features like that of Gaidius, but is as a whole 

 distinctly more slender. The right endopodite, which is half as long as Re I and distally and posteriorly 

 has a short tooth, is distally inflated and spoon-shaped; the Re II has the anterior process which 

 encloses the bowel-shaped cavity shorter and more prominent (fig. 3 f). The endopodite of the left legs 

 is almost 2 / 3 of the length of the Re I; it is indistinctly divided into 3 segments, of which the second 

 is the shortest, and has no terminal seta. Inwards, at the base of Re III, a small process bearing 4 

 short hairs is found. 



Y (Stage V). Size: female from Thor St. 183 (?) 4*0 mm.; anterior division 3-2; urosome o-8 mm. 

 Farran's young male measured 4-3 mm. 



The relative length of the four abdominal somites and the furca is: 19, 21, 18, 19 and 17; 

 the furcal rami are 1-3 as long as wide. The antenmdae are distinctly longer than in the adult, and 

 the measurements are slightly different. The maxillulae have, in contrast to the female, only 10 setae 

 in the Re, and the lob. IV of the second basipodite of the maxillipeds bears 3 setae as in the male, in 

 addition to the sensory lobe. The articulation between Re I and II in the first pair of legs is only 

 indicated anteriorly as a faint line; the St. of the Re III in the second pair of legs has only 20 teeth, 

 the setae along the inner margin of the basipodite of the fourth pair of legs are rather stiff. The 



