new Parasitic Copepods on Fish. 89 



in length from without inwards ; the first joint of the inner 

 branch has one, the second six short hairs. Hamulus very 

 small. 



Fourth perceopod of considerable size and robust form, con- 

 sisting of four joints, the last terminating in a minute spur, 

 close to which are placed three end-claws, two others being 

 placed at the inner end of the second and third joints ; each 

 of these five is seen to have a minutely crenate edge, which 

 on higher magnification shows a beautifully serrated border, 

 transversely striated ; an abortive fifth limb is found at the 

 angle of the genital segment in the form of a small tubercle, 

 giving rise to three short plumose hairs. 



Genital segment oval, with a truncated posterior border ; 

 equals half the length of the cephalothorax. 



Abdomen elongated, as long as the last segment, con- 

 sisting of a prolonged first joint and a second of a square form. 



Caudal plates small, slightly longer than broad, with three 

 long terminal plumose hairs and two minute ones on the 

 outer border. 



Length 6-7 milliin. 



Anuretes, Hell. 

 Anuretes per plexus , sp. n. (PI. V. fig. 3.) 



This genus was formed by Heller, and has been retained 

 by Gerstaecker, the original specimen having been described 

 by Rroyer as Lepeophtheirus Ileckelii ; it is distinguished 

 by " the entire deficiency of separate tail-segments," ail other 

 parts agreeing with the genus Lepeophtheirus. The first 

 specimen was obtained from Ephippus gigas in the Brazilian 

 sea, described by " Roller " as Caligus Heckelii } being pre- 

 served in the Vienna Museum. A second specimen was 

 taken from the same species of fish off New Orleans by 

 Rroyer ; he states that " this species has a moderately wide 

 diffusion." I have been fortunate enough in a far removed 

 locality — namely at Trincomalee, Ceylon — to find on a species 

 of Lutjanus about a dozen specimens of a second form of this 

 peculiar animal, though the necessity for making for it a 

 distinct genus seems to me rather doubtful, for in some the 

 position of the caudal plates is as Rroyer describes, but in a 

 few these project a little beyond the posterior edge of the 

 genital segment, though in none does " the abdomen appear 

 drawn out." 



Female. — Cephalothorax rather broader than long, nar- 

 rowing in front ; the posterior lateral angles obtuse, not 



