1 STALK- AND SESSILE-EYED CRUSTACEA 
119. Sphaeroma obtusa. 
Sphaeroma obtusa, Dana, U.S. Explor. Exped. xiv, Crust. part 11, 
p. 779, pl. lu, fig. 5, (1853). 
Body smooth, naked. Feet smooth, nearly naked. Segments of 
thorax similar. Last abdominal segment sub-triangular, the sides 
towards apex abruptly convergent, apex obtuse, ventral cavity broad 
behind. Caudal lamelle shorter than abdomen, entire, both truncate 
at apex. Feet smooth, nearly naked, all equally slender, second pair 
longer than first or third. Colour, dull yellow or brownish yellow. 
Length 3 lines. (D.). 
New Zealand; Bay of Islands, along shores of Parua Harbour, 
(Dana). 
ISOCLADUS. : 
Tsocladus, Miers, Ann. Mag. Nat. Hist. (ser. 4) xvii, p. 228, (1876). 
Convex, somewhat widening posteriorly. Seventh segment of the 
body in the male with a long median dorsal spme. Terminal segment 
of the body narrowing posteriorly, and acute at the extremity. Caudal 
appendages subequal, of a slightly sigmoid shape, and acute at the 
extremity. 
The females in this genus, and in the two allied genera mentioned 
below, are smaller than the males, and do not increase so much in 
width posteriorly ; the spine of the seventh thoracic segment is absent ; 
the rami of the caudal appendages are shorter, and there are usually 
two small prominences on the upper surface of the last abdominal 
segment. 
The nearly allied genus Zuzara, of Leach, (Dict. Sci. Nat. xii, p. 344, 
1818), has unequal caudal appendages, and the abdomen truncate at 
the extremity, with a median terminal spine. Cyclura, of Stebbing, 
(Journ. Linn. Soc. xii, p. 146, 1874), has the caudal appendages 
broad, unequal, and rounded at the extremity. 
120. Isocladus armatus. 
Sphaeroma armata, M. Edw. Hist. Nat. Crust ii, p. 210, (1840); 
White, Dieffenb. New Zeal. li. p. 268, (1848); Dana, U.S. Explor. 
Exped. xiv, Crust. part 1, p. 780, pl. li, fig. 7, (1853). 
Smooth, seventh segment of the body with a conical median tooth 
directed backward. Last segment of the tail triangular, terminating 
in a large obtuse tooth, which reaches beyond the plates of the terminal 
