MOEPHOLOGT OF CYCLOPS. 



333 



Tlie sexual duets are described as outgrowths from the sexual 

 glands, themselves derived from a pair of cells of the serosa of 

 the gut of the JSTauplius as stated by Erie. About 32 sperma- 

 tozoa appear to be formed from each male ovum or spermato- 

 spore. The author is inclined to accept Gruber's view that the 

 expulsive bodies of the spermatophore are a second form of 

 spermatozoa. 



The author then proceeds to a discussion on the position of 

 the Copepoda. He adduces the following points : — 



(a) The plasticity of the eye, derived from the triune inverted 

 eye of the Nauplius, and the absence of paired compound eyes. 



(b) The hiramous condition of the sioimming-feet, and the cha- 

 racters of the appendages generally, especially the plasticity of 

 the onaccillce. 



(c) The slight development of the pleura. 



(d) The absence of gills, and the functional anal respiration. 



(e) The plasticity of the fore part of the alimentary canal. 



(f) The circulation and heart. 



(g) The general correspondence of the form of the body with 

 that of the Protozoea and Zoea larva. 



By converging arguments from these points, it is sbown that 

 Copepoda would represent the most primitive Crustacea, from 

 which the others can be derived according to the following 

 phylogeny :— 



Copepoda Natantia {Mesopedd). 



sCopepoda Parasitica. 



Eudiplopida. 



Eudiplopida Stenopleura 

 (Branchiura). 



Eudiplopida Bathypleura. 



Cirripedia. Rhizocephala. Ostracoda. 



Protophyllopoda 



or 

 Podobranchiata. 



