1434 THE VOYAGE OF H.M.S. CHALLENGER. 



TJie Eyes occupying all the surface of the large head except a small triangular space 

 on the top at the centre of the hind margin aud the slightly depressed tract down the 

 front which in the male is occupied by the antennae. 



Upper Antenna? of the male planted in the frontal cavity, which does not reach the 

 top of the head. The three joints of the peduncle very short and closely combined, the 

 first the longest and a little inflated ; the first joint of the flagellum directed upwards 

 so as to form an angle with the peduncle, 1 which it exceeds in length, on the lower side 

 produced into a pointed process under the first two or three or four short succeeding joints, 

 the whole under side of the joint and both sides of the process furnished with a close 

 brush of filaments set in transverse rows ; the joints after the first abruptly narrower, 

 the second to the fifth short, the rest rather elongate ; these delicate flagella were broken 

 in almost all the specimens ; in one specimen twenty-one joints were counted ; each 

 joint, the first three excepted, has on the under side two little prominences, from which 

 depend small groups of filaments. In the female the upper antennae are represented 

 only by a pair of minute tubercles. 



Lower Antennas of the male inserted immediately below the upper. The peduncle 

 with three free joints, the first having a very' convex upper margin, the second shorter, 

 scarcely longer than broad, the third longer than the first, slightly bent upwards and 

 having its lower margin much more convex than the upper ; the flagellum abruptly 

 narrower than the peduncle, the first joint a little knobbed at the base as if to form a 

 ball and socket joint with the end of the peduncle ; the general structure of the 

 flagellum as in the upper antennae, but with no very short joints at the base, the joints 

 in general longer, with three instead of two groups of filaments on the under side ; in 

 one specimen there were twelve joints remaining, but many may have been missing. 

 Milne-Edwards assigns forty joints to the flagellum of the upper antennae, and more 

 than fifty to that of the lower in his description of " Anchylomera Blossevilleii." The 

 figures a.s.A., and a.i.A., were not drawn from the same specimen as the full figure 

 and the other separate parts. 



Mandibles. — The cutting edge very slightly convex, striated, having a tooth at the 

 upper end curving downwards and another at the lower end curving a little upwards ; 

 the secondary plate on the left mandible has its edge more or less dentate, and approaches 

 much nearer the edge of the primary below than above ; on the lower margin of the 

 mandible, behind the lower tooth of the cutting plate, there is a bush of spine-like bristles ; 

 the molar tubercle, much broader than deep, has its crown set round with spinules, the 

 outer margin, which is next the trunk of the mandible and nearly parallel with the 

 cutting edge, being crenulate ; the palp placed behind the molar tubercle, at about the 

 centre of the mandible, has the first joint large, much broader than either of the following, 



1 Milne-Edwards says of the antennas "les inferieures coudees," but the "elbow" is more pronounced between the 

 peduncle and flagellum of the upper antennse, than between the joints of the peduncle of the lower. 



