IOO 



emaro-ination as the apex merges into the dorsal line. The rostrum is moderately large and the 

 rami are more elongated than in the female. 



The abdomen is composed of five segments. The total length of the abdomen and furca 

 is contained two and one-third times in the total length of the cephalotkorax, from the frontal 

 margin to the base of the genital segment. The second segment is longer than any of the 

 others, and is distinctly expanded at its distal end. The fifth segment is very small. The furcal 

 joints are about as long as broad, and are twice the length of the anal segment. 



The antennules are composed of nineteen joints, and extend to the end of the second 

 abdominal segment. The eighth joint is long and represents the result of the fusing of three 

 or four joints. The basal joints are furnished with sensory organs. 



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

 female, and are only slightly modified. 



The four pairs of swimming feet are also similar to those of the female, except that the 

 surface of the second and third joints of the exopodite and exdopodite of the fourth feet, is 

 beset with groups of fine points. 



The fifth pair of feet is moderately large and prehensile. It is not unlike the male fifth 

 pair of Scaphocalanus in general appearance. The second joint of the right basiopodite is dilated 

 at the proximal end, where it bears a moderately long styliform endopodite. The endopodite 

 appears to be one-jointed with a lamelliform distal portion. The distal portion of the second 

 joint of the right basiopodite is much contracted, and simply merges into the three-jointed 

 exopodite. The second joint of the exopodite bears a small outer-edge spine at its distal end. 

 The third joint is irregularly curved, and has a distinct knee-like projection on its inner surface. 

 The joints of the basiopodite of the left foot are elongated and somewhat cylindrical. The 

 exopodite is composed of three joints. The terminal joint is short and spiniform and bears a fringe 

 of short hairs on its inner surface. The endopodite is one-jointed. The joint is of irregular shape 

 and is rather longer than the exopodite. The outer margin of the distal end is slightly crenulate. 



Length of male 5,75 mm. 



The character of the male fifth pair with its one-jointed endopodite of both feet, the 

 structure of the fifth pair of the female, the bifurcate rostrum, and the short terminal joint of 

 the exopodite of the antennae, are sufficiënt to separate this genus from the other members of 

 the family. 



Lophothrix frontalis has a clistribution somewhat similar to that of Scaphocalanus magnus 

 in the tropical and temperate regions. It has been recorded by Farran from the deep water 

 plankton taken off the West of Ireland, and my father has obtained it from the deep water 

 plankton of the Faröe Channel. 



Genus Macandrewella nov. 



Female. The head is completely fused with the first thoracic segment and possesses a 

 circular lens-like organ on the frontal margin. The fourth and fifth thoracic segments are 

 completely separated. The rostrum is represented by slender filaments attached to a common 



