segments. The ventra] surface of the genital segment is only slightly dilated. The second segment 

 is as long as the combined length of the third and fourth segments. The furcal joints are as 

 long as broad, and are equal to the length of the third segment. 



The antennules are twenty-four-jointed and extend to the furcal joints. 



The antennae, mandibles, maxillae and maxillipedes are similar to those of Scottocalanus 

 securifrons. 



The four pairs of swimming feet are also smilar to those of that species. 



The free joint of the fifth pair of feet is distinctly swollen at the distal end, and the 

 inner margin is sharply concave in the middle. The long spine is three times the length of the 

 joint, and the small one is only equal to one-twenty-fifth of the length of the long spine. 



Male — 3,54 mm. 



Yiewed from above, the body is elongate and narrow. It is less robust than in the 

 male of Scottocalanus persecans. Seen from the sicle, the apex of the crest appears quite angular, 

 and the rostral spines are much shorter than those of Scottocalanus persecans. The last thoracic 

 segment is narrowly rounded at the apex, and the notch is less obvious. 



The combined length of the abclomen and furca is contained two and one-third times 

 in the total length of the ccftlialothorax, from the apex of the crest to the base of the genital 



segment. 



The antennules are composed of twenty joints and extend to to the end of the fourth 

 abdominal segment. 



The antennae, mandibles, maxillae and maxillipedes are similar to those of the female. 



The four pairs of swimming feet are also similar to those of the female. 



The fifth pair of feet has a general resemblance to that of Scottocalanus persecans, but 

 can be separated on careful examination. The narrow part of the second joint of the basiopodite 

 of the right foot, is produced into a strong tooth near the proximal end of the inner margin. 

 The distal inner margin is distinctly swollen, then concave, and again dilated. The exopodite 

 is two-jointed. The first joint is comparatively long and is greatly curved. The second joint is 

 small and lamelliform. lts lensnh is contained fullv four times in the total length of the first 

 joint. The shape and the proportional length of the joints of exopodite are quite different 

 from Scottocalanus persecans. The endopodite extends beyond the distal end of the second joint 

 of the basiopodite, and the apex is lamelliform. The joints of the exopodite of the left foot 

 are cylindrical and of nearly equal length. The apex of the second joint terminates in a rather 

 complicated process, and bears two curved spines. The endopodite is moderately stout and is 

 much shorter than the exopodite. 



The male of Scottocalanus farraui, although apparently resembling the male of Scotto- 

 calanus persecans in appearance, can readily be separated by the comparatively short and undivided 

 apical spines of the rostrum, by the difference in the proportional length of the joints of the 

 exopodite of the right fifth foot, and by the endopodite of the left fifth foot being much shorter 

 than the exopodite. 



Occurrence. — Twenty-three females and thirty males were obtained from the plankton 



collected at the following 'stations. 



107 



