CALANID2E. 35 



Temora, and other genera have characters very similar 

 to the Pontellinoe group in the antennae and footjaws. 



The chief points of generic distinction are to be 

 found in the structure 'of the inner branches of the 

 swimming feet more especially in those of the first 

 and second pairs, in the characters of the fifth pair 

 of feet and of the mandibles, maxillae, and foot- 

 jaws. As regards the mouth organs the most 

 noteworthy modifications are those found in Candace, 

 where the mandible is remarkably slender and its palp 

 much dilated, the maxillae being at the same time 

 of quite abnormal structure ; and in Dias and Parapon- 

 tella where the apical portion of the lower footjaws is 

 so much reduced in size as to be almost aborted. 



Specific distinctions have sometimes been founded 

 on the number of joints in the branches of the swim- 

 ming feet, but it must be borne in mind that this 

 character is liable to vary with the stage of development 

 of the animal. A table of such variations is given 

 amongst the remarks on the genus Cyclops, and I 

 hope, in an appendix to the second volume, to illus- 

 trate from Arctic specimens in the possession of the 

 Rev. A. M. Norman a somewhat similar process of 

 development in Calanus. 



