COPEPODA 



79 



The Antamulac are in the main like Sars' figure; the segments 24^25 are almost completely 

 fused; the segments 8<n>o, and 10 as well as the 20 — 21 are almost completely fused on the right side, 

 but fairly well distinguished on the left side. The segments 8^9 are a little longer than 2, which is 

 about i-2 as long as segment 20; the posterior seta of segment 23 is very short. The antennae are 

 scarcely different from those of the female, in contrast to the mandibulac which, except for the presence 

 of 2 instead of a single seta in Ri, are completely like Sars' figure without distinct manducatory plate. 

 The manducatory part of the maxillulac is scarcely developed, and the rudimentary Li I bears a few 

 short sensory appendages instead of spines; the Li 2 is not developed; the Li 3 bears 2 feathery 

 bristles, the basipodite 3, and the endopodite 9 setae; the exopodite possesses 9 strong plumous setae. 

 The maxillae are comparatively more slender than figured by Sars, with a number of very short 

 spinules and three proximal knobs. The maxillipeds differ from those of the females by the com- 

 paratively long Basp. Ill, which is 17 as long as the second. The first four pair of legs is scarcely 

 different from those of the females. Pes V is scarcely different from Sars' description; the Ri sin 

 (fig. 3 e) is rather elongate; about the structure of the right and the left exopodite I refer to figs 3g — f. 



Y (Stage V). Size: Specimen from Thor St. 72 measured 3-05 ; anterior division 2*4 mm., 

 urosome 0*65 mm. Another specimen was 3*65 mm. 



The abdomen consists as usual of four somites, of which the second is the longest; the 

 antennulae are comparatively longer than in the females, and reach to about the end of the second 

 abdominal somite; the articular membrane between the Ri I — II pes II is only indicated by a faint 

 line. The pes V of the male is, as shown in PI. II fig. 3 h, like that of Gaidius. 



Yo* (Stage IV). Size: Specimen from Thor St. 82 measured 2 - i6 mm.; anterior division 17 mm.; 

 urosome 0-46. 



The shape of the body is like that of the adult specimens, but the abdomen has only three 

 somites; the number of segments is somewhat reduced in pes IV, as Re II 00 III and Ri II 03 III are 

 mor a less completely fused. Two glandular pores were observed in Re III and one in Re I. The 

 pes V is rather rudimentary, as seen in fig. 3 i. 



Variation. In a few specimens from Thor St. 172 % I 9°5> which, except for the less promi- 

 nent sexual area, were in all other respects like the adult females, a fifth pair of legs, as shown in 

 fig. 3J, with the right leg the longer, was found. In a specimen from St. 72 (Thor 1905) the left leg 

 was longer and more slender (fig. 3 1), and in one from St. 173 (Thor 7/ g 1905) fig. 3 k the right leg 

 was again the longer. In two specimens from St. 104 (Thor 2 4/ 5 1904), and in one from St. 99 (Thor 

 22 / s 1904), the pes V was like fig. 3e; the last mentioned specimens as well as one from St. 153 (7/ 9 

 1905) with pes V dext. > sin. and well developed eggs had the genital somite of female type, but without 

 distinct receptaculum seminis. 



As most of the mentioned specimens were in all respects but the presence of pes V like the 

 typical ones, and as the mentioned stucture was variable to a degree, it must be regarded as a kind 

 of abnormity (cf. similar structures in Pseudocalanus). 



Parasites. In a single adult female from Thor 1 / 9 St. 285 a stalked parasite was found, attached 

 to the first basipodite laterally on the anterior surface of the right maxilla; the body consisted of 



