708 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



the genital segment is one-half wider than long, and its posterior 

 processes are stout, conical, and considerably divergent. 



In this species also there are never more than a few scattered spines 

 along the margins of the segment and on its processes, while in many 

 specimens the entire segment is without spines. 



There are also numerous minor differences in the detail of the 

 appendages, particularly the mouth parts and the third thorax legs. 

 In the males the chief differences lie in the relative size and shape of 

 the genital segment and abdomen as already brought out in the key 

 on p. 703. 



From Kroyer's species, earoJuirlie^ the present form differs in the 

 size and position of the dorsal plates on the free segment, in the size 

 and shape of the genital segment, and in the detail of the appendages- 

 In the female described b}' Kroyer the dorsal plates on the free seg- 

 ment were close together, their bases fused, with an angular interven- 

 ing space, and they reached back to the center of the body of the geni- 

 tal segment. 



Bassett-Smith says of the female which he described: '' In outward 

 form the dorsal plate covering the last thoracic segment was much 

 less apparent."'^ There must have been two of these plates, and the 

 fact that he speaks of them as one would indicate thorough fusion. 

 Here, on the contrary, we find the dorsal plates noticeably distinct to 

 their very bases which are widel}- separated, while they scarceU" over- 

 lap the genital segment at all, to say nothing of reaching its center. 



Again the female described by Kroyer had a genital segment more 

 than three-fifths as wide as the carapace, and the body of it, exclusive 

 of the processes, is nearh^ twice as wide as long. In the female 

 described by Bassett-Smith the genital segment was two-thirds the 

 width of the carapace and more than three times as wide as long. 

 But in the present species the genital segment even of a female cai'iy- 

 ing egg-strings is not half the width of the carapace, and is less than 

 one-third wider than long. 



Here again also the genital segment is smooth or has but few setse, 

 while in carcharise there is a heavy fringe around the entire margin 

 and along^the processes. 



ALEBION GLABER h Wilson. 

 Plate XIX, figs. 49-61; figs. 17 and 18, pp. 695 and 696. 

 Alehion glabruin Wilson. 1905, p. 129. 



Feuiale. — Carapace orbicular, squarel}^ truncated posteriorly. Fron- 

 tal plates well defined. Posterior sinuses broad and deeper than in 

 gracile. Longitudinal grooves between the carapace areas • widely 

 separated leaving a very broad median area. 



"Some new or rare I'arasitic Copepo<ls found on Fish in the Indo-tropic Region, 

 1898, 1.. 367. 



'' For the cliange in gender, see p. 707. 



