1887.] 



ON CYCLESTHERIA HISLOPI. 



5 



Lave made any closer investigation of the anatomical structure 

 of the animal, nor have had opportunity of watching the pe- 

 culiar propagation of this form, its true relations to other Phyllopoda 

 have not been recognized. Baird referred this form to the genus 

 Éstheria on account of the distinctly prominent umbones of the 

 shell, whereas Dr. Bra dy describes it as a species of the genus 

 Limnadia, believing the antennulæ to have greater resemblance to 

 those in Limnadia than to the same organs in Estheria. The fact 

 is, however, that the present form cannot properly be referred 

 either to the genus Estheria or to Limnadia, but evidently 

 represents the type of a very distinct new genus, to which the 

 name of Cyclestheria may appropriately be applied on account of 

 the peculiar rounded Cyclas-like shell, distinguishing this form 

 from all other known bivalve Phyllopoda. 



In the following pages I propose to give a more detailed 

 account of this interesting Phyllopod, of which a number of 

 specimens have been successfully hatched and domesticated in 

 one of my aquaries. 



