26 THE HANCOCK PACIFIC EXPEDITIONS VOL. 2 



the center; lunules small, semilunar, and projecting but little. Median 

 posterior lobe one third of the carapace width, not reaching behind 

 the lateral lobes, with rather angular corners; lateral lobes curved 

 strongly inward. Free segment one fourth the width of the cara- 

 pace and considerably widened through the bases of the fourth 

 legs; genital segment longer than the carapace, and half as wide as 

 long, with nearly parallel sides and rounded lobes at the posterior 

 corners. The anterior end of the segment is contracted into a long 

 neck, narrower than the free segment and more or less wrinkled. 

 On the ventral surface of the segment near the posterior end the 

 two sexual openings, which lead to the semen receptacles, project 

 backward a little side by side, and to their outer ends are attached 

 the spermatophores. The latter are nearly spherical and reach back 

 to about the center of the abdomen, thus forming a structure which 

 at first sight suggests the rudimentary segment in Pandarus, to which 

 however, it bears no analogy. The abdomen is one-jointed, one 

 fourth the length and one third the width of the genital segment; 

 the caudal rami are minute and armed with tiny setae. 



The terminal joint of the first antennae is linear and elongate; 

 the second antennae are of medium size with a stout claw curved 

 into a half circle. The maxilliped has a considerably inflated basal 

 joint and a strong terminal claw. The first leg carrier a rudimentary 

 endopod which is finger-like and shows traces of segmentation and 

 is tipped with a very short spine. The spine on the basal segment 

 of the third exopod is exceptionally large and very strongly curved; 

 the fourth leg is four-jointed with 5 spines, the three terminal joints 

 combined a little shorter than the basal joint. These legs are weak 

 and slender and scarcely reach the thickened portion of the genital 

 segment. Total length, 5 mm. Carapace 2 mm. long, 2.2 mm. wide. 

 Ovisacs 5 mm. long. 



One of the females from Caranx hippos, with ovisacs, has been 

 selected and given Cat. No. 69866 U.S.N.M. 



Caligus isonyx Steenstrup & Liitken 



Caligus isonyx Steenstrup & Liitken. Kong. Danske Vidensk. Selsk. Skrifter, 5 



raekke, p. 18, pi. 3, fig. 5, 1861. 



This species was based upon a single female taken from a great 



barracuda, Sphyraena barracuda, in the West Indies and no other 



specimen has been obtained during the 75 years since then. The 



present collection, however, includes 3 females from a flying fish, 



