COPEPODA 



213 



and slender spines (text-fig. 67 a). The fifth thoracic somite is well distinguished in front, and the 

 regularly rounded lateral corners are scarcely produced. 



The abdomen is one third as long as the anterior division; the comparative length of the 

 abdominal somites and the furca is 18, 67, 53, 48, 10 and 18. 



The antennulae extend at least to the end of the third abdominal somite ; the shape is similar 

 to that of S. magnus, but the proximal part is straighter, the restrictions at the base of the basal 

 segments are less pronounced, and the angle between segments 14 and 15 in less marked. Segments 

 8039 are almost completely fused with 10—12, segments 20 and 21 and 24 — 25 are completely fused. 

 The appendages are scarcely different from those of S. magnus\ the segment 20 does not possess any 

 setae. The segments 8<^ 12 are n as long as segments 23 — 25, not, as in S. magnus and related species, 

 much (1-5) shorter, and segment 22 is 1-2 shorter than segment 19. The antenna are scarcely different 

 from those of adult females, and the mandibidae are very much like, but the manducatory parts are less 

 powerful, and the third basipodite is comparatively wider, with two short setae inwards, and a more 

 distally placed knob representing a third one. The Li I of the maxillulae is fairly well developed, 

 and has at least 12 rather short and soft setae; in Li 

 III only 4 setae were observed, but in other respects 

 scarcely any difference was observed. The maxillae 

 have the sensory appendages, especially the amalliform 

 ones, slightly developed; the maxillipeds are like those 

 of S. magnus. 



The natatory legs are scarcely different from 

 those of the female. The fifth pair of legs extends 

 almost to the end of the abdomen, and shows great 

 similarity to that of S. magnus. The right endopodite, 

 which extends somewhat beyond the end of the first 

 outer segment, is styliform, with the terminal part 



fairly well articulated. The right exopodite (text-fig. 67 c) has the first segment articulated upon a 

 long outer process of the third basipodite as long as the segment itself; the two pieces form a natural 

 joint, elongated and outwards convex; the second outer segment is much shorter than the first; the 

 third somewhat lamelliform segment is again somewhat longer, convex inwards, with a distinct angular 

 process in the middle directed forwards, and produced into a pointed eminence, at the base of which 

 a small conical process is found. The basal segments of the left leg are long and slender, and of almost 

 equal length; the left endopodite (text-fig. 67 d) is like that of ^. magnus, with the two first segments 

 long and slender, and the third rather short and pointed; the left exopodite is somewhat shorter than 

 the endopodite, and its third segment is triangularly attenuated, with fairly long setae inwards and 

 terminally and short ones outwards. 



The afiterior surface of the labrum is very much like that of the female; anteriorly three 

 irregular series of apparently very short setae are found; the series along the hinder margin is wanting. 

 The oral surface has anteriorly a small conical process 011 each side, behind which at least two striated 

 median spots are found; on each side an irregularly striated protuberance was found; no hairs were 



Text-fig. 67. Lophothrix frontalis f (j 1 . 



a. Head X 18. b. Abdomen >( 18. c. Pes V dext. 



Re II— III X 59- d. Pes V sin. X 59- 



