PARASITIC COPEPODS — WILSON 539 



species, Achtheinus dentatus, and were so described and figured. The 

 two males t)f this original lot were mistakenly considered immature 

 females and the supposedly unique male described as the male type 

 of A. dentatus. However, if the description and figures of those so- 

 called immature females be compared with the figures of the females 

 here described it is at once apparent that they are not females but 

 the true males of the species A, dentatics. The single male first 

 described as the type male of this species differs radically from the 

 males that correctly represent this species. 



The males here described having now been established as true 

 males, it becomes necessary to replace the male generic diagnosis of 

 the genus Achtheinus previously given : 



Male diagnosis: Carapace elliptical, without conspicilla; posterior 

 lobes conical, without accessory lobes. Free thorax comparatively 

 wide, its two pairs of dorsal plates confined to the lateral margins; 

 genital segment without a dorsal plate, but with fifth leg rudiments. 

 Abdomen triangular, wholly visible dorsally. Second antennae 

 stout, blunt, and without teeth. Maxillae conical, maxilliped with 

 a strong terminal claw. Four pairs of biramose swimming legs, 

 rami of first three pairs 2-segmented, of the fourth pair 1-segmented. 



Genus TEREDICOLA Wilson, 1942 



TEREDICOLA TYPICA Wilson 



Plate 31, Figubes 172-179 



Teredicola typica Wilson, 1942, p. 60, fig. 1. 



This species was described from a dozen specimens including both 

 sexes taken from the body cavities of Teredos in Honolulu Harbor, 

 Oahu, Hawaii, by Dr. C. H. Edmondson. A single male and a female 

 were selected to serve as types of the genus and species, U.S.N.M. 

 No. 79639. The original diagnosis was as follows : 



Female: First three thoracic segments more or less fused with the head and 

 with one another to form a cylindrical body a little more than twice as long 

 as wide. Fourth and fifth segments reduced to a third of the width of the 

 first and second segments, the fifth segment twice as long as the fourth. Geni- 

 tal segment about the same size as the fifth segment and snbspherical in form. 

 Abdomen 3-segmented, the first and third segments about the same width and 

 length, the second segment shorter and a trifle narrower. Caudal rami narrow 

 cylindrical, as long as the anal segment and widely divergent, each with two 

 terminal setae as long as the ramus itself. 



First antennae 6-segmented, the two basal segments considerably widened, 

 the third segment the longest and the fifth segment the shortest, all except the 

 basal segment bearing setae. The second maxilla and maxilliped are each made 

 up of a single stout segment tipped with a strong claw, the one on the maxilla 

 acute and curved into a semicircle, the one on the maxilliped blunt and nearly 

 straight. Two pairs of biramose swimming legs, the rami 2-segmented and of 

 approximately the same length. Each end segment is armed with many setae 



