RErOET ON THE AMPHirODA. 873 



Eyes small, oval, situated near the lateral lobes of the head. 



Upper Antenna— First joint of the peduncle much thicker, but not much longer than 

 the second, twice as long as broad ; third joint scarcely more than half the length of the 

 second; flagellum of forty-four or more joints, of which the first is longest, the first six 

 carry short cylinders, and of the rest each alternate joint ; the joints of the peduncle have 

 a few short cilia or setules, and have their distal margins more or less lobed ; the third 

 has also on the inner side a minute representative of a secondary flagellum, rounded, 

 armed with a single cilium. 



Lower Antennae thinner and much shorter than the upper. Peduncle shorter than 

 the peduncle of the upper antennas. The first joint not greatly expanded, the second 

 produced on one side all along the third, which it partially clasps, the opening of the (not 

 conical) gland-cone being on the inside at the distal angle of the clasping part ; the third 

 joint short, its distal margin irregular, armed with small spines that show each an 

 accessory thread ; the fourth joint equal in length to the preceding three united, with 

 groups of spines on its surface and at the apex ; the fifth joint a little longer than the 

 fourth, with groups of spines or short setae on the surface and at the apex ; the flagellum 

 of twenty-four joints, of which the first is the longest ; these joints are distally furnished 

 with groups of setules. 



Upper Lip having the outer plate apically divided by a small oblique emargination 

 into two unequal lobes. 



Mandibles. — The cutting plate rather small, its edge divided into six or seven 

 consecutive teeth ; the secondary plate on the left mandible nearly as large as the 

 principal, divided similarly into six teeth ; this plate on the right mandible is slighter, 

 divided into two teeth, one of which, having the appearance of being broken or much 

 worn, is approached by the serrate outer edge of the plate ; the spine row of thirteen 

 slender, backward curving, spinuliferous spines, the row filling up the small space 

 between the cutting plates and the prominent molar tubercle ; crown of the molar 

 tubercle oval, dentate, and ciliated ; the articulating process blunt, close to the base of 

 the palp which is just over the molar tubercle ; the first joint of the palp carrying one or 

 two spines, the second joint having several along the front margin and surface adjoining 

 it, its hind margin a little concave ; the third joint subequal in length to the first and 

 second united, its outer border convex, its outer surface covered with adpressed cilia, its 

 inner margin for almost the whole extent fringed with pectinate spines, of which there 

 are on the apex two very long followed by two shorter. 



Lower Lip. — The principal lobes very broad and thick, much ciliated apically ; the 

 mandibular processes very short. 



First Maxillse. — Inner plate squarish oval, with four plumose setae on the apex, 

 alternately long and short; the outer plate much broader than the inner, with 

 ten spines on the truncate distal margin, the one row slender and denticulate, the 



(ZOOL. CHALL. EXP. — PAET LXVIL — 1887.) XxX 110 



