1320 THE VOYAGE OF H.M.S. CHALLENGER. 



1886. Thaumatops pellucida, Bovallius, Biliang till K. Svensk. Vetensk. Akad. Handl., 



Ed. 11, No. 9, p. 8. 



1887. ,, Neptunus, Bovallius, Systematical List of Amph. Hyper., Bihang. till K. 



Svensk. Vetensk. Akad. Handl, Bd. 11, No. 16, p. 16. 

 1887. „ pellucida, Bovallius, Systematical List of Amph. Hyper., Bihang till K. 



Svensk. Vetensk. Akad. Handl., Bd. 11, No. 16, p. 16. 



Head inflated, wider than any part of the body, longer than the upper antennae, 

 rather broader than long, the upper surface almost entirely mapped out into minute 

 hexagonal spaces in correspondence with the multitudinous ocelli ; the lower surface 

 fringed on either side by a row of thirteen or fourteen denticles, the wide space between 

 these rows being occupied by a thin transparent membrane, from which, on either 

 side of the mouth-organs and for a short space above them, project two short rows of 

 denticles, five in each row, the highest pair of denticles being much the longest, and 

 the next pair longer than the three lowest pairs, the lowest approaching the outer angle 

 of the mandibles. The first two segments of the perseon are coalesced into one, which 

 is rather longer than the next following, the seventh is longer than those which 

 precede it, but shorter than the first segment of the pleon ; the segments of the pleon 

 diminish in length successively ; in breadth the animal tapers from the base of the 

 head to the telson. The segments are all carinate and centrally dentate, except the 

 small (coalesced) fifth and sixth segments of the pleon. The seventh segment of the 

 perseon and the first three of the pleon have each three teeth along the central ridge, 

 the others have two apiece. The segments of the perseon and some of those of the 

 pleon have the hind margin fringed with minute denticles, the composite first segment 

 of the perseon having also a row near the front corresponding probably with the line of 

 coalescence. The joints of all the limbs are prismatic in transverse section. 



Eyes (see description of the female). 



Upper Antennas thirteen -twentieths of an inch in length, the first joint the stoutest, 

 short, two or three times as long as broad, seemingly constituting a one-jointed 

 peduncle, the following joint many times as long, of triangular transverse section, 

 tapering, having on the inner side for most of its length a row of small setules not very 

 closely set and scarcely showing beyond the margin, the apex produced into a small 

 tooth on one side ; planted within but jjrojecting beyond the tooth is a small narrow 

 tapering third joint. 



Lower Antennas wanting, unless the foremost pair of ventral denticles may be 

 regarded as rudiments of these organs. 



Epistome small, unsymmetrically helmet-shaped. In the upper figure of the mouth 

 organs the epistome and upper lip are at the top, the maxillipeds at the bottom, the 

 mandibles projecting on either side ; the palps of the first maxillae meet just over the 

 emargination of the upper lip ; the second maxillse are crossed by the outer plates of the 

 maxillipeds. In the lower figure, the maxillse and maxillipeds having been removed, the 



