■J292 CRUSTACEA. 



Length, one-twelfth of an inch. Colour, yellowish. 

 The shell in a side view appears very slightly flattened behind, and 

 the outline of the beak does not project beyond the general outline of 

 the front. This beak is short and quite narrow in profile. The 

 length of the shell is not one and a half times its breadth. 



The eyes consist of spherical lenses upon a mass of dark pigment. 

 A distinct cornea was seen, extending over the whole, and having a 

 simple undivided surface ; and also within the cornea one of the 

 humours, as shown in fig. 1 d. One of the lenses was seen to have 

 an equatorial line, which had the appearance shown in figure d', as if 

 minute oval and rounded pieces had been chipped out. It extended 

 over the outer side of the lens, as seen in the right lens on figure d. 



The appendages consist, as represented in figure c, of two pairs of 

 antennae, one of mandibular feet, three of maxillae, one ovarian pair 

 of legs, besides the caudal extremity. 



The first pair of antennae (ce and e) has seven joints, the last two 

 minute, and the third and fifth shorter than the others. These organs 

 are geniculated between the first and second joints, which are nearly 

 equal in length ; in ce, there is only an end view of the basal joint. 

 There are one or two short setae at the apex of the second and fourth 

 joints ; at apex of filth, two plumose setse nearly as long as last four 

 joints of organ; at apex of sixth and seventh, four longer naked setae, 

 which spread widely at the will of the animal ; they are hardly as 

 long as the last six joints of the organ. 



The second pair of antennas (cf) has a very large subtriangular base. 

 The longer branch (the only one observed) consists of an oblong cylin- 

 drical joint, and seven short joints, the latter together about equalling 

 the preceding one. Each of the short joints is furnished with a long 

 plumose seta, longer than the branch. These setae are delicately arti- 

 culate, as shown in fig. /. 



The mandibular feet {eg, g, hg) are geniculate at the second articu- 

 lation. The fifst joint bears on one side a thin and flexible short- 

 ciliate process, which is the true mandibular process, although so weak 

 and small. The second joint is stout and oblong, and bears a few 

 naked setae, besides a longer which is setulose in tufts. The third is 

 short. The fourth (or finger) is long, and tapering from a stout base; 

 it is furnished on its sides with several setae, some half as long as the 

 joint. The claw at the extremity is small. 



The buccal mass (ch, h) in a ventral view has large obtuse promi- 



