[currie] plankton COPEPODS 215 



some and large sized but few teeth on BI of p5 (Fig. 29). From 

 the observations of the specimens of Table II it appears that there 

 is no constant external feature which will serve to distinguish the 

 sexes in stage V. 



Exceptional Cases. One specimen, number 13, was peculiar in 

 that the withdrawn parts of the setae in the rami were wrinkled, Fig. 

 26. This was probably due to the pressure of the crowded tissues, 

 but it is worth mentioning that the wrinkling in the two rami was 

 practically identical. Number 17 was exceptional in that the distal 

 point of the external ramus Re of the left p5 was obpyriform in shape 

 (Fig. 32) while that of the right p5 was like those of the other swimming 

 feet (Fig. 2)3). Another Calanus stage V obtained from "Prince" Sta. 

 3 on May 24th, showed an abnormality in the external rami of p5. 

 Instead of the usual three Se on the distal joint, there were only two 

 Se. (Fig. 35). 



Stage VI. This is the adult stage which terminates the series 

 of ecdyses and, although feeding continues, the miain energy of the 

 copepod is used in reproduction. 



Length at stage VI. Of twenty-seven fem.ales examined, the 

 lengths ranged from 2.92 mm. to 5.1mm., the average length being 

 3.6 mm. As in stages III and V, only one average length could be 

 distinguished. 



Coxal Teeth of female at stage VI. The first basal joint of p5 is 

 denticulate along the inner margin. The teeth are in a long regular 

 row, usually with a sigmoid bend in the middle of the row, extending 

 the whole length of the joint. The average number of teeth is 34; 

 34-1 for the right p5 and 34-17 for the left. This average is greater 

 than that for stage V. 



Setce. In the typical condition, as figured by G. O. Sars, there is 

 one Se on both Ri of p5 in the female. Out of 59 specimens examined, 

 43 were typical, 15 had two Se, one had 2 Se on one Ri and one on the 

 other. The two Se when present, are slender, as in stage V. 



Length of male. Of 29 specimens examined, the length varied 

 from 3 mm. to 5 mm., the average being 3-5 mm. 



Coxal teeth of male. The denticulations on the basal joint of 

 p5 are much larger and fewer in number than those of the female. 

 Usually the distal end of the row is terminated by a large jointed 

 tooth. The average number of teeth is 22; 23-4 for the right and 

 22-5 for the left. 



Setœ of male fifth foot. In the typical condition, figured by Sars, 

 there are two Se on the Ri of p5 in the male. These setae are much 

 stouter than those of stage V. All those examined conformed to the 

 type except one that had one Se on the right Ri and two on the left. 



