40 



Journal of Comparative Neurology. 



The following table has been compiled in order to facilitate 

 a comparative study of this olfactory organ : 



Table showing the relative size of Leydig' s 

 organ in a feiv Cypridce. 



NAME OF SPECIMEN. 



Candona acuminata (Fischer) 9 



Candona crogmani Turner 9, type .-_. 

 K " " exception. 



$ 



Candona delaioarensis Turner, 9 



$ 



Candona fal>,rfori?tis (Fischer) 9 



Cyclocypris Irvis ( O. F. MuUer) 



Cypria exculpta (Fischer) 



Cypria ineqtiivalva Turner, 9 



Cypria ophthalmica (Jurine) 



Cypridopsis 7Jidtia (O. F. Miiller) 



Cvprinotits burlingtonensis. Turner, 9 -- 



Cyprinotus crena. Turner, 9 



Cyprinotus incongniens (Ramdohr) 



Cypris fuscata (Fischer) 



Cvpris herricki Txxrner 9 



MICROMILLIMETERS 



1250 



1520 



1520 

 950 



1030 



570 



640 

 520 



580 



700 

 1600 



1230 

 '350 



1500 

 3000 



Sensory Seta. — In addition to the sense organs already de- 

 scribed there are several types of sensory setae that deserve at 

 least a passing notice. Not having been able to trace a nerve 

 into any of these setae, I have given but a brief notice of them. 



At the tip of the antennules and antennae of all the 

 CypridcP there occurs a two-segmented sensory seta [fig. 20]. 

 This seta is longest in Taplilocypris, where it is as long as the 

 terminal claw. In Condona fabcefoi-mis Fischer this seta is 48 

 micromillimeters long. In this case, the terminal segment is 

 ten micromillimeters long. Owing to its small size and to the 

 number and size of the associated claws and filaments, this 

 organ is a very difficult object to study. 



At the extremity of the fourth segment of the antenna of 

 Notodromas there is a peculiar seta with a funnel-shaped tip 

 [fig. 28]. 



At the tip of the fourth segment of the antenna of the male 

 members of the genera Candona, Candonopsis and Cypris there 

 is a peculiar two-jointed seta [fig. 24-27]. Dr. Wenzel Vavra 



