NO. 2286. THE NEW COPEFOD FAMILY SPHTRIIDAE— WILSON. 595 



covered by a carapace, which reaches back to the bases of the maxilli- 

 peds and does not extend down very far along the sides, thus leaving 

 the mouth parts practically free. The cephalothorax is followed by 

 a small free segment, but the remaining thorax segments are fused 

 together with only indistinct joints. 



There is no abdomen, but each of the posterior corners of the 

 genital segment is prolonged into a conical process terminating in a 

 short spine. These processes are close together on either side of the 

 midline, while outside of and anterior to them is a pair of shorter 

 processes Avith bluntly rounded tips, and anterior to these a pair of 

 small knobs. 



The first antennae are indistinctly three-jointed, slender, nnd con- 

 ical, tipped with four spines, and with a few setae along the sides. 

 The second antennae are broad and flattened, made up of a 

 stout basal portion which is two-jointed and two terminal rami. Of 

 the latter the endoped is one-jointed with a broad and spatulate 

 tip armed with a single spine; the exopod is indistinctly three- 

 jointed, the last joint carrying a pair of curved claws opposed to each 

 other like the jaws of a chela. Inside of these second antennae 

 on the base of the mouth tube is a pair of maxillae, each made 

 up of a basal joint and two rami. The endopod (dorsal) is one- 

 jointed, bluntly rounded at the tip and unarmed; tli© exopod is 

 two-jointed, the terminal joint slender, flattened and tipped with 

 two short spines. The mouth tube is relatively large and broadly 

 conical, and extends a little Avay beyond the tips of the antennae; 

 the mouth opening is surrounded by a fringe of hairs. The second 

 maxillae and maxillipeds are very large; each is made up of three 

 joints, the basal ones stout and armed with powerful muscles, the 

 terminal one a strong curved claw. The basal joints of the maxil- 

 lipeds are completely fused across the midline. 



The testes are situated in the back of the head over the bases 

 of the maxillipeds. The vas deferens leads along the side of 

 the thorax to the spermatophore re^-eptacle at the extreme pos- 

 terior end of the genital segment. These receptacles are rather 

 small and each contains but a single spermatophore with a short 

 and nearly straight tube. 



Color, a uniform snow-white. 



Total length, 2 mm. Diameter of cephalothorax, 0.50 mm. 



(ferox, fierce, bloodthirsty.) 



Remarks. — This genus Avas obtained from the gill cavity of its 

 host and in every instance was attached to the integument which 

 forms the outer wall between the arches. The head and entire neck 

 was buried in the tissues beneath this integument, the neck ex- 

 tending toward the nearest gill arch so as to bring the head and 

 month in '^]n^Q. pioximitv to one of the large arterie:^ whicli snj)- 



