PARASITIC COPEPODS — WILSON 541 



lateral margins. The fifth segment with a small dorsal plate not 

 wide enough to reach the lateral margins and concealed in dorsal 

 view beneath the epimeral plate of the fourth segment. Genital 

 segment more or less divided transversely, the halves with a conical 

 process at each posterior corner. Caudal rami wider than long, the 

 second inner seta greatly elongated. 



First antennae 9-segmented in the female, 6-segmented in the male 

 and geniculate, the terminal part made up of two segments. Mandib- 

 ular palp biramose; maxilliped chelate. First four pairs of legs 

 biramose, the rami 3-segmented, fifth legs uniramose, 2-seginented. 



Remarks. — This genus is closely related to Alteutha but differs 

 enough from it in the body proportions, the dorsal epimeral plates, 

 the first and fifth legs, and the male antennae to be established as 

 a separate genus. 



Genotype. — Unicalteutha ovalis^ new species. 



UNICALTEUTHA OVALIS, new si[>ecies 



Plate 34, Figures 209-218 



Eighteen females and 4 males were obtained by Prof. W. Templeman 

 from the outside surface of lobsters in Placentia Bay, Newfoundland, 

 late in June 1939, while he was carrying on investigations for the 

 Fisheries Research Institute at St. John's. A female and a male 

 have been selected as holotype and allotype, respectively, of the new 

 species, U.S.N.M. No. 79695. 



Female. — Body elliptical and strongly depressed and expanded 

 laterally as in Alteutha. Head fused with the first segment and 

 covered with a carapace one-fourth wider than the length on the 

 midline, its lateral margins turned down with acute posterior corners. 

 The first three segments behind the carapace are covered with short 

 dorsal epimeral plates, the first one as wide as the carapace, the other 

 two successively narrower. All three of these plates are turned 

 down at their lateral margins and acutely produced at their pos- 

 terior corners. The third of these plates is longer than either of the 

 others and extends backward to cover and conceal the fifth segment 

 in dorsal view. The fifth segment is only two-fifths as wide as the 

 fourth and has a dorsal plate which is transversely elliptical and does 

 not reach the lateral margins of the segment, but it does project 

 backward a little over the genital segment. 



The urosome is only a fifth as long as the metasome and is 

 strongly flattened. The genital segment is as wide as the fifth segment 

 and is partially divided by lateral invaginations. The posterior cor- 

 ners of each half are produced conically backward and are armed with 

 short setae. The abdomen is 2-segmented, both segments with conical 



