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The antennules are twenty-jointed and extend to the end of the thorax. 



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

 armata. The apical portion of the second maxillipedes is composed of four joints. 



The four pairs of swimming feet are also similar to those of Pontellopsis armata. 



The fifth pair of feet is asymmetrical. The inner margin of the right exopodite is produced 

 into a strong spine. The exopodite of the left foot is distinctly shorter than the exopodite of the 

 right foot. The inner margin has no spine. The endopodites are nearly symmetrical, and the 

 apex is bifurcate (Plate LIV, fig. 6). 



Male — length 1,67 mm. 



The male bears a general resemblance to the female, but the last thoracic segment is 

 distinctly asymmetrical and the abdomen is five-jointed, The left distal end of the last thoracic 

 segment is the same as that of the female. The right side is produced into a moderately 

 strong, curved, spiniform process, that extends to the end of the third abdominal segment. The 

 right side of the third abdominal segment is expanded into a well defined tooth. The furcal 

 joints are proportionally longer than those of the female (Plate LIV, fig. 7). 



The right antennule is composed of about twelve distinct joints. The three middle joints 

 are greatly infiated. The upper margin of the second proximal hinge joint is produced distally 

 into a serrate tooth. The lamina on the upper margin of the proximal hinge joint is also serrate. 

 The proximal portion of the upper margin of the distal hinge joint is furnished with moderately 

 long slender spines (Plate LIV, fig. 9). 



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



The first four pairs of feet are also the same as in the female. 



The thumb-like projection of the first joint of the right exopodite of the fifth pair is 

 slender, and is of very remarkable length. The claw-like terminal joint is comparatively short. 

 The produced outer distal end of the first joint of the left exopodite extends to near the end 

 of the second joint. The second joint is short. It is furnished with one outer marginal spine, 

 two sub-apical spines, and one apical spine (Plate LIV, fig. 10). 



The females of this species can readily be separated from any of the other females of 

 the genus, by the spines on the dorsal surface of the genital segment. The structure of the 

 fifth pair of feet of the two sexes readily distinguishes this species from any of the other 

 members of the genus. The remarkably long thumb-like projection of the first joint of the right 

 exopodite of the male fifth pair, is sufficiënt to separate the male of this species, from any 

 of the other known males. 



Occurrence. — Seven specimens were obtained from the plankton collected at the 

 following stations. 



Stat. 3J, 1 female and 1 male. — Stat. 109, 2 females and 1 male. — Stat. 213, 1 female 

 and 1 male. 



Genus Pontellina Dana, 1852. 



Pontellina is closely related to the genus Pontellopsis, but the last thoracic segment of 

 both the male and female is asymmetrical. The right furcal joint of the two sexes is very 



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