CYCLOPS. 99 



further examination, be found to belong to some of the 

 allied genera. For example, Cyclops nigricauda, Nor- 

 man = Thorellia brunnea, Boeck ; and C. littoralis, 

 Brady = Cyclopina littoralis of this monograph. 

 Amongst species which must for the present remain 

 doubtful are C. ovalis, Brady, C. magniceps, Lillje- 

 borg, and G. Clausii, Lubbock, of which last-named 

 I have seen no specimens, notwithstanding Sir John 

 Lubbock's kind effort to supply me. Failing these, I 

 am unable to find sufficient distinctive character in 

 the published description of C. Clausii to warrant my 

 retaining it here as a separate species. 



The points on which specific diagnosis in this genus 

 chiefly depends are the characters of the first 

 antenna3 and fifth pair of feet. As offering subsidiary 

 characters the spinous armature of the swimming 

 feet, together with the tail-segments and setas, are also 

 important. The mode of disposition of the ovisacs, 

 and to a certain extent the colouring of these and 

 other parts of the body, afford also useful helps to 

 diagnosis. 



The following table, exhibiting the changes of 

 structure which take place during the development 

 of Cyclops, is taken from Dr. Claus's work on the 

 6 Free-living Copepoda of Germany and the Mediter- 

 ranean,' p. 82. 



