ART. 1 



A NEW FRESH-WATER COPEPOD WIL.LEY 



11 



The chief distinguishing characteristics of the junior stage are the 

 length of the sensory chib of the fourth joint of the anterior antennae, 

 exceeding the end (fig. 22); the absence of an si on the proximal 

 joint of the inner branch of the first foot (fig. 23) ; the small size of 

 the inner branches of the second and third feet (figs. 24 and 25) ; the 

 uniarticulate inner branch of the fourth foot (fig. 26) ; the presence 

 of a varying number, from three to five, of spinules at the edge of the 

 anal operculum (fig. 27); and the absence of crests on itic caudal 

 stylets (figs. 27 and 28). Another very striking feature is afforded 

 by the presence of setae on the inner sides of the outer branches of 

 the second, third, and fourth pairs of swimming feet. These inner 

 setae, so characteristic of Canthocamptus, are thus discarded at the 



Figs. 29-30.— Moraria laurentica. 29, Last three segments of trunk showing sroh swimming 

 feet and fifth foot, and the genital segment undivided. 30, fifth foot of junior 



final metamorphosis, with the exception of that on the third joint of 

 the fourth foot (p4re3si). The inner branches of the feet exhibit a 

 retarded development, the outer branches a precocious differentiation. 

 The fifth foot (figs. 29 and 30) lacks the innermost seta of the small 

 distal joint. 



The types of this species consist of a male and an ovigerous female 

 with an attached spermatophore. They bear the numbers 59850 

 (female holotype) and 59851 (male paratype) in the United States 

 National Museum. At the same time it is the type of the genus 

 Moraria on the American continent. 



The immature stages of fresh-water harpacticoids have been very 

 imperfectly studied and in this instance the junior presents some 

 sharply defined features of unexpected significance. 



