12 Report on the Parasitic Copepoda collected during 

 the survey of the Juan Fernandez Islands, 1916-1917. 



By 

 CHARLES BRANCH WILSON, D. Sc, Ph. D. 



State Normal School, Westfield, Massachusetts. 

 With Plates 2—4. 



Introductory. During the survey the zoologist, Mr. K. BACKSTROM, 

 collected five vials of parasitic copepods which, upon examination, prove to 

 be of peculiar interest. 



In the first place they come from a region where very little collecting 

 has ever been done. The eastern portion of the southern Pacific is virtually 

 unknown, as far as its copepod parasites are concerned. The present lot are 

 the first to be obtained from these particular islands, and practically the first 

 from the entire region. 



Then the hosts upon which they were found are exceptional, the large 

 scombrid, the white-spotted cabrilla, the little clingfish, the curious wreckfish, 

 and the Chilian sculpin. It is not strange, therefore, that three and probably 

 four of the vials should prove to be new species, and that one of them con- 

 stitutes a new genus. 



The specimens are all deposited in the Museum of Natural History at 

 Stockholm, Sweden. 



Juanettia, new genus. — Plate 2; 3 fig. 7. 



Generic characters of female. Head fused with the first thorax seg- 

 ment, and the two separated from the second segment by a short neck; a pair 

 of fleshy bifurcate processes on the ventral surface at the posterior corners of 

 the cephalothorax. Second, third, and fourth thorax segments distinctly separ- 

 ated, each with a lateral cylindrical process on either side. Second segment 

 with a pair of large conical horns on the dorsal surface at the anterior margin; 

 egg strings cylindrical, multiseriate. First antennae enlarged and fleshy at the 

 base; second pair modified into stout prehensile hooks. Mandibles toothed on 



