598 PROCEEDINQii OF THE NATIONAL MUSEUM. vol.55. 



Total length, including posterior processes, 28 mm. Head, 3.50 

 mm. long, 4 mm. wide. Neck, 16 mm. long, 1 mm. wide. Trunk, 3 

 nmi. long and wide. Posterior processes, 4 mm. long, 1 mm. wide. 

 Egg strings, 7.50 mm. long, 1 mm. wide. 



{versicolor.) variegated in color.) 



Specific characters of male. — Cephalothorax two-fifths longer than 

 the rest of the body, with a well-rounded carapace; one free thorax 

 seg-ment, the rest of the body fused without traces of segmentation. 

 Posterior processes shorter than in the ferox male, but ending in 

 sharp setae. First antennae indistinctly three- jointed and tipped 

 with two setae; second pair two-jointed, the terminal joint bifurcate, 

 the endopod armed with two setae, the exopod ending in a chela. 

 First maxillae uniramose, one-jointed, and ending in three stout 

 spines; second maxillae consisting of a stout joint tipped with a 

 strong curved claw; maxillipeds with basal joints swollen and fused 

 across the midline, the second and third joints separate, the third 

 joint terminated by a strong chela made up of two claws of nearly 

 equal size, the outer one with an accessory spine at its base. Testes, 

 sperm ducts, and spermatophore receptacles like those in ferox. 



Total length, 1.80 mm. Diameter of cephalothorax, 0.45 mm. 

 Diameter of body, 0.35 mm. 



Remarks. — This species was always found at the corner of the first 

 gill arch in the floor of the mouth. Two may be found in the same 

 fish, one on either side, but no more than this and never at any other 

 spot. The head and long neck are buried in the tissues the same as 

 fcrox.^ and are surrounded by a sheath of tough membrane. 



PERIPLEXIS, nev/ genus. 



Generic characters of female. — Cephalothorax soft, C3^1indricai 

 md transversely wrinkled; neck much narrower than the cephalo- 

 thorax, fully chitinized, intricately bent and twisted, and armed 

 along at least the anterior half of its length with numerous short 

 chitin horns and processes; enlarged posteriorly and joined to the 

 genital segment at the center of the anterior end. Trunk elongate, 

 cordate, flattened dorsoventrally, with rows of shallow pits on the 

 dorsal and ventral surfaces as in Rehelula; no posterior lateral lobes ; 

 ^^enital processes spherical and close together, their bases joined 

 across the midline. Abdomen spherical and minute, attached vent- 

 rally to the bases of the genital processes ; posterior processes attached 

 in the groove between the abdomen and the genital segment on the 

 dorsal surface; each made up of three large lobes flattened together. 

 Egg strings two-thirds as wide as the posterior processes and longer 

 than the trunk. Head squarely truncated anteriorly and surrounded 



