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



somite, of which those on the second and sixth somites are the longest. Each of the six 

 somites is also armed on each side with a strong tooth, of which the anterior is the 

 smallest, and the others gradually increase in length until the posterior, which is armed 

 with two longer ones on each side. 



The telson is broadly bifurcate and armed with six spine-like hairs on each ramus. 



The ocellus is still visible. 



The ophthalmopoda are club-shaped and well developed. 



The first pair of antennae appears to be three-jointed, and represents only the 

 peduncle, it is narrow, cylindrical, and has the apex tipped with a few hairs. 



The second pair of antenna? carries a long and well-formed scaphocerite, furnished 

 on the outer margin with a row of short hairs, as shown in Suhm's drawing (E) (fig 45), 

 and on the inner and distal margins with a series of longer ones. 



The mandible is not furnished with a synaphipod, and the two succeeding pairs of 

 oral appendages are not distinguishable. 



The first maxdlipede or third pair of siagnopoda (fig. 2, g) is single-branched, the 

 posterior margin being even and unarmed, and the anterior divided into numerous lobes 

 (six or eight), each of which supports a series of short stiff hairs, radiating perpendicu- 

 larly to the surface of each lobe. 



The two pairs of gnathopoda (fig. 2, h) are biramose and fringed with a series of 

 delicate hairs. 



The pereiopoda (fig. 2, to) are in an early stage of development, the anterior being 

 the most advanced ; they are biramose and tipped with a few delicate hairs. 



The pleopoda are not developed, nor is the germ of one visible until we come 

 to the sixth pair, which is formed to the extent that it reaches halfway down the 

 telson, and is biramose, saccular, and as yet unfringed with hairs. 



From the same locality is another specimen, about 2 "5 mm. in length, from which the 

 drawings of the maxillipede (fig. 2, g), the first gnathopod (fig. 2, h), and third pereiopod 

 (fig. 2, to), on PI. XLVIII. were taken. The pereiopoda are not so far advanced, and 

 none of the pleopoda, not even the posterior pair, are distinguishable. 



These two specimens are mounted on one slide, and labelled by Willemoes-Suhm, and I 

 should have supposed it probable that his figure (E) was taken from the specimen showing 

 the ventral surface, had he not stated that it was drawn from a specimen taken in lat. 18° 

 N., whereas these must have been, from the date on the slide, taken in lat. 25° N. 



On PL XLV1I. (fig. 3) is a specimen possessing all the features characteristic of the 

 genus Aristeus, as far as can be judged by external form only. 

 This was taken at Sydney, Wellington. 

 Length, about G mm. (0'25 in.). 

 It has the rostrum long, strong, and pointed, and armed at the base of the dorsal 



