NO. 1504. AMERICAN PARASITIC COPEPODS— WILSON. 697 



for it a distinct subfamily. That we are now justified in doings, and 

 accordingly the name of the oldest of the five genera, Earyphorus 

 (Milne-Edwards, 1840), has been selected for the name of the sub- 

 family, which becomes the Euryphorinse. 



SUMMARY. 



1. The life history of the genera belonging- to this subfamily is 

 similar to that of the Caliginte except in the following details. 



2. The balancers near the posterior end of the nauplius's body are 

 more slender, are cylindrical throughout, and stand out at right angles 

 to the central axis. 



3. In the metanauplius the first thorax segment is completeh' fused 

 with the carapace, a condition as far advanced as that of the chalimus 

 in the Caligina?. It thus exhibits the first step toward that precocious 

 development which characterizes the more degenerate families of these 

 parasites. 



4. The seta? on the terminal joint of the first antenna? in the meta- 

 nauplius are not plumose, but are very long and dichotomously branched 

 toward their tips, forming a web or mat like that in certain algse. They 

 thus retain much of the locomotor function which they possessed in the 

 nauplius stage. 



5. The second maxillse in the metanauplius consist of two entirely 

 separate rami of about the same size. The endopod is short and stout 

 and slightly bifurcate at the tip; the exopod consists of two slender 

 diverging spines united at the base. 



6. In the chalimus stage there is no frontal filament; instead, the 

 second antenna? are enlarged and extend straight forward in front of 

 the carapace, serving as the only organs of attachment. 



7. In the chalimus stage also the second and third segments are 

 fused inte7' st\ while the separation of the fourth segment is clearly 

 indicated by a well-marked constriction. This is another evidence of 

 precocious development, for in the following molt, when the fourth 

 segment is fully separated in both subfamilies, we find it without 

 appendages in the Caliginffi, but with a pair in the Euryphorinte. 



8. The second maxilUe in the chalimus are simple, the exopod hav- 

 ing thus early degenerated into the form seen in the adult, a papilla 

 fused with the base of the endopod and carrying two small spines. 



9. The fourth legs when they first appear are distinctly bifurcate at 

 the tips, the two rami being minute. 



10. This life history clearly separates the genera here included from 

 the Caligin* on the one hand, and, reenforced by the morphology of 

 the adults, from the Pandarina? on the other. We are thus justified 

 in constituting for them a separate subfamily, intermediate between 

 the two, which is named for the oldest genus included in it, the 

 Euryphorinse. 



