PARASITIC COPEPODS — WILSON 533 



tached to the ventral surface of the genital segment and more or less 

 covered by the latter. The males have always been found swimming 

 freely in the plankton, as active as any of the pelagic forms, but the 

 females, like those of all the other Caligidae, are fixed to their host 

 and are never taken in the tow. The size and scarcity of their hosts 

 help to explain why no females have hitherto been secured. 



It is worthy of repetition here that Bassett-Smith (15'99, p. 460) 

 declared he had personally examined many specimens of both sexes 

 of Dysgamus in the British Museum. 



DYSGAMUS RHINODONTIS (Wright) 



Staslotes rliinodontis Wkight, 1876, p. 583, pi. 35, figs. 1-14. 



Wright established a new genus and species of copepods upon fe- 

 male specimens taken from the gills of a "shark {Rhinodon typicus) ," 

 collected in the Seychelles northeast of Madagascar. The name 

 Stasiotes was used 12 years previously by Jan for a snake genus, and 

 a new name was suggested by the present author ( 1907c, p. 439) . Com- 

 parison of Wright's original description and figures with those given 

 above for Dysgamus atlanticus proves that the two species are con- 

 generic. The two species cannot be regarded as synonymous, how- 

 ever, as there are many differences in the proportions and markings of 

 the body regions and in the details of the appendages, especially the 

 second antennae, the maxillipeds, and the fourth legs. Accordingly 

 Wright's specimens retain the original specific name and will be known 

 as Dysgamus rliinodontis (Wright). 



Genus LEPEOPHTHEIRUS Norman, 1832 



LEPEOPHTHEIRUS CHRISTIANENSIS, new species 



Plate 28, Figukes 124-131 



Thirty specimens, including both sexes, were obtained from a sea 

 catfish {GaJeichtkys sp.) at Pass Christian, Miss. The female holo- 

 type and male allotype are U.S.N.M. No. 60548. 



Female. — Carapace circular in outline, as wide as long and highly 

 vaulted dorsally ; median posterior lobe more than half the carapace 

 width and scarcely projecting behind the lateral lobes. The latter are 

 very short, curved inward, and bluntly rounded at their tips. The 

 central longitudinal ribs are widely separated and diverge anteriorly. 

 The free segment is reduced to a fourth of the width of the carapace 

 and is contracted to a short neck anteriorly. The genital segment is 

 acorn-shaped, three-fourths as long and five-eighths as wide as the 

 carapace, narrowed into a short neck anteriorly and almost squarely 

 truncated posteriorly. Abdomen 1-segmented, one-fourth as long 



