124 



BEITISH COPEPODA. 



antennae of the male, too, are very much less 

 specialised than in the true Cyclopidae, and one is 

 tempted to query whether this may not be a slight 

 degree of that retrograde development which is so 

 conspicuously shown in the lower parasitic Crustacea, 

 where the males have become little more than mere 

 sperm-sacs. 



This family is here represented by the genera 

 Notodelphys, Doropygus, Botachus, Notopterophorus, 

 and Ascidicola. 



Synopsis of Genera of Notodelphyidm. 



External 

 and 



internal 

 branches 

 of swim- 

 ming feet 

 composed 



each of 



three 



joints ; 



fifth pair 



of feet 



composed 



of 



"one branch 



two 

 branches ; 

 posterior 

 antennae 

 terminat- 

 ing in 



.Doropygus. 



several short setae... Notodelphys. 

 f simple. ..Botachus. 



two 



stout 



claws ; 



dorsal 



margin 



of 

 cephalo- 

 thoracic 



pro- 

 duced 

 into 

 wing- 

 like 



seg- expan- 

 ments (^ sions j 



> Notopterophorus. 



^two joints Ascidicola. 



Sub-family 1. Notodelphyin^. 



Body flattened, head consolidated with the first 

 thoracic segment ; six abdominal segments in both 

 sexes. Anterior antennae 10— 15 -jointed, and in the 

 male adapted for clasping, as in Cyclops. Caudal 



