1894.] NATURAL SCIENCES OF PHILADELPHIA. 91 



second segments of the pleon form a short row on each side, but 

 never form a transverse band crossing the segment. 



The eyes and eye- lobes are large, the latter being let into deep re- 

 cesses in the anterior lateral portion of the carapace. 



The antennulte consist of three joints, of which the basal one is 

 somewhat longer than the other twocoml)ined. A small knob (rudi- 

 mentary flagellum) terminates each. In the male the antennula? 

 usually about equal in length the carapace with the first free segment, 

 but are sometimes considerably longer. In the female they are about 

 equal to the carapace alone. 



The antennse lie close beneath the antennulse, by which they are 

 slightly exceeded in length in both male and female. They are five- 

 jointed, the fourth joint being the longest, slightly exceeding the sec- 

 ond; the fifth, third and first following in the order named, the last 

 mentioned being very short. Each antenna is terminated by a 

 densely setiferous rudimentary flagellum considerably longer than 

 that of the antennules and sometimes imperfectly articulated, 



The mandibles are of the usual form, curved inwards at the tip 

 where each bears a pair of horny teeth, shaped like the limbs of the 

 letter U. Proximad of the middle, a stout trausverse column passes 

 mediad bearing at its end an oval molar plate traversed by a series 

 of parallel ridges with deep grooves between. Under a high power 

 each ridge appears to be broken up by shallow indentations into a 

 series of rounded teeth. 



The first maxillae consist of a stout forwardly directed column 

 and a posteriorly directed palpus, bearing at its end a brush of 

 seven or eight long sette. The anterior ramus is stout and 

 curved towards the median line, bearing at its tip a group 

 of about eight stout, curved spines, each with two series of fine, 

 apically directed, denticuli. A brush of stifi" setse lies near the base, 

 and laterad of, the spines. A smaller group of spines lie on one 

 face near the tip; these are not denticulate and lack the brown color 

 of those in the apical group. 



The maxillipeds are adherent basally by means of short, stout 

 hooks. The basal joints are prolonged on their anterior or oral 

 aspects into plate-like processes, which are coupled together in the 

 median line. Each basal joint bears a flattened palpus, consisting of four 

 joints, the terminal three being furnished with long setaj. The distal 

 joint is strongly flexed on the penultimate. A somcAvhat falciform 



