K0.2194. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 41 



2''i/pe of the genus. — Leptotrachelus truchae Brian, monotypic. 

 (Lepiotraclielus, Xctttos, slender and rpaxv^os, neck.) 

 licmarks. — Brian established this odd genus upon several speci- 

 mens sent to him by the Italian investigator, Filippo Silvestri, and 

 obtained from ^^ Pcrcichti/s triicha,^'' taken in the Santa Cruz River, 

 Patagonia. He first named the genus Silvestrla, but this name being 

 preoccupied he changed it to Leptotrachelus. It apparently bears 

 more resemblance to the Lernaeinae than to the other subfamilies, 

 and, as it came from fresh water, we may leave it here until further 

 data are obtained. 



Genus THERODAMAS Kr^yer. 



TJicrodamns Kr^yee, Bidrag til Kundskab om Snyltekrebsene, 1S63, p. 316, 

 pi. 15, fig. 4, a — /. 



External generic characters of female. — Body divided into two 

 parts, the anterior one resembling a slender neck ending in a swollen 

 spherical head, the posterior one considerably wider, distinctly seg- 

 mented, and tapering backwards. Anterior portion really a median 

 dorsal process, but carrying on its swollen tip a pair of stout 

 uncinate second antennae. First segment of the posterior portion the 

 true head, bearing the proboscis and mouth-parts on its ventral 

 surface. First, second, third, and fourth thorax segments the same 

 width as the head and each bearing a pair of swimming legs. 

 Genital segment strongly tapered posteriorly; abdomen short and 

 deeply parted in the center; anal laminae small and armed with 

 stout setae; egg strings spindle-shaped; eggs small, multiseriate, and 

 not definitely arranged. First antennae unknown; second pair stout 

 and uncinate; proboscis short and blunt; one pair of mandibles, two 

 pairs of maxillae, no maxillipeds; swimming legs well separated, all 

 four pairs biramose, rami 3-jointed and armed with plumose setae. 



Type of the genus. — Therodamas serrani Kr0yer, monotypic. 



{Therodamas^ ©spoSajxas, a Scythian king who fed lions with 

 human flesh.) 



Remarks. — Kr0yer obtained a goodly number of adult females from 

 the gills of a species of Serranus in the Danish West Indies. The 

 present author searched long and carefully for this odd genus upon 

 various genera and species of the groupers at Jamaica in 1910, but 

 without success. 



The chief peculiarity of the genus is the curious median and dorsal 

 prolongation of the head, which looks exactly like a slender neck, 

 and to complete the resemblance its anterior end is enlarged like a 

 head and carries on its dorsal anterior margin a pair of uncinate 

 second antennae like those of the other Lernaean genera. The first 

 antennae are apparently lacking, but possibly Kr0yer overlooked 



