40 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. GO 



third legs are of the usual pattern, well separated and standing out 

 at right angles to the ventral surface. The fourth legs are divided 

 nearly to their base ; the rami are cylindrical, slender, and taper to a 

 rather fine point; they are about two-thirds as long as the body. 

 A pair of fifth legs is present in the form of short tapering rami, 

 one on either side of the fifth segment, in front of the genital segment. 



Color (preserved material) yellowish brown.' 



Total length, 3.15 mm. Cephalothorax, 1 mm. long, 1 mm. wide. 

 Greatest width of body, 1.15 mm. Length of fourth legs, 2 mm. : of 

 egg strings, 4 mm. 



{rathhuni^ to Eichard Eathbun, who did much excellent v^ork on 

 the parasitic copepods.) 



Bem-arks. — The distinguishing characters of this new species are 

 the position of the first antennae, removed some distance from the 

 frontal margin, the deep and narrow sinus on either side of the an- 

 tennal area, the reentrant sinus at the tip of the dorsal plate, the pres- 

 ence of a fifth pair of legs, and the details of the various appendages. 



The species can not be very common, for after these two specimens 

 were obtained a large number of hogfish were examined without 

 finding any more of the parasites. 



LERNANTHROPUS LEIDYI, new species. 



Plate 3, figs. 23-27 ; plate 4, figs. 28-30. 



Host and record of spechnens. — Forty females were obtained from 

 the gills of the white perch, Morone americana, at Beaufort, North 

 Carolina, July 12, 1905. One of these has been selected as the typo 

 of the species with Cat. No. 53572, U.S.N.M. The others become 

 paratypes with Cat. No. 53573, U.S.N.M. A second lot of 60 females 

 was obtained from the gills of the yellowtail, Bairdiella chrysura^ 

 July 20, 1905, also at Beaufort; these have been given Cat. No. 

 53574, U.S.N.M. A third lot was obtained from the same host at 

 Beaufort by Dr. Edwin Linton September 19, 1902. This lot con- 

 tained a single male and 30 females and has been given Cat. No. 

 63575, U.S.N.M., the male being isolated and placed in a separate vial. 



Speciiic characters of female. — General body form oblong, about 

 twice as long as wide, with the fourth legs projecting their entire 

 length. Cephalothorax subquadrangular in dorsal view, slightly 

 narrowed anteriorly, the lateral margins curled over ventrally a long 

 distance. A narrow antennal area is separated at the anterior mar- 

 gin, to the sides of which are attached the first antennae. Anterior 

 portion of dorsal plate much wider than posterior in young females 

 and somewhat wider in mature adults, with a deep sinus on each 

 lateral margin at the junction of the two portions. Posterior por- 

 tion narrowed and shortened in young females, leaving both the 



