ISO 
“TERRA NOVA ” EXPEDITION. 
Adult. $ 8*45 mm. by 7 ‘ 7 mm. (Fig. 2a.) 
First Antennae.—The second and third segments bear over twenty bristles on the 
dorsal surface. 
Second Antennae.—The basal joint of the secondary branch bears eight or ten hairs, 
second joint five hairs. 
Mandibles.—First sensory joint bears numerous hairs on ventral edge. Second 
joint about ten. Third joint very many. 
Cleaning foot.—Well developed. 
Furca.—Three pairs of stout, finely serrated spines, followed by about nine pairs of 
plumose bristles. 
Stage II. $ 2’5 mm. by 2• 1 mm. (Fig. 2b.) 
First Antennae.—Second, third and fourth segments each bear one large plumose 
hair or bristle on the dorsal surface. 
Second Antennae.—The basal joint of the secondary branch bears one or two hairs, 
second joint hairless. 
Mandibles.—First sensory joint bears about sixteen hairs, second joint two, 
third joint many. 
Cleaning foot.—Undevelc>ped. 
Furca.—Three pairs of more slender, finely serrated spines, followed by three or 
four pairs of plumose bristles. 
Stage III. $ 1‘9 mm. by 1'65 mm. (Fig. 2c.) 
First Antennae.—Third segment alone bears a single hair. 
G o 
Second Antennae.—Secondary branch hairless. 
Mandibles.—First sensory joint bears five hairs, second joint two, third joint about 
twelve hairs. 
Cleaning foot.-—Undevel oped. 
Furca.—Three pairs of spines, the third not serrate, imperfectly separated from 
furcal plate, and followed by a few simple hairs. 
There may be an older stage between Stage II and the adult, which is not 
represented by the specimens obtained. 
Measurement of Specimens ( ? ? ), in mm. 
Adult. 8’45 x 7*7 
r 2‘97 x 2• 65(rightvalve2• 60) 
2’75 x 2 • 55 (right valve2 • 45) 
2‘50 x 2‘09 
2•35 x 2•04 
Stage II. 2 • 30 x 2 • 04 
2-30 x 2-01 
2-30 x 2-09 
2-30 x 2-09 
.2-24 x 1-99 
Stage III. c 
' 1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
89 x 1-66 
89 x 1-64 
89 x 1-63 
84 x 1-62 
84 x 1-62 
84 x 1-61 
84 x 1-61 
84 x 1-61 
79 x 1-60 
79 x 1-60 
79 x D60 
