414 
¥. A. POTTS. 
given to the individuals to which it will afterwards be con- 
venient to refer : 
1 
Length 
Width. 
Appro.ximate number of 
segments. 
Condition of posterior 
region. 
1 
Victoi’i.i : 
I 
19 mm. 
2 mm. 
Head fragment. 
— 
II 
00 
2 
no segments -j- tail of 
about 30 segments. 
Tail only 6 mm. in 
length. 
III 
41 „ 
2 
220 segments. 
Tail long, graduat- 
ing insensibly into 
stock. 
IV 
45 „ 
3 „ 
220 segments. 
Ditto. 
V 
55 ,, 
3-5 „ 
195 segments -|- tail of 
about 40. 
Tail2 mm.longwith- 
out caudal cirri. 
VI 
12 „ 
4 „ 
172 segments -|- tail of 
about 100. 
Tail 14 mm. long. 
VII 
85 „ 
2-5 „ 
Incomplete. 
— 
VIII 
94 „ 
3 
356 segments. 
Cluster of young sto- 
lons at tail. 
IX 
Friday Harbour : 
Tail fragment. 
Cluster of more ad- 
vanced stolons. 
X 
66 mm. 
3 mm. 
125 segments -|- tail of 
90 or more. 
The specimen originally procured by the Columbia 
University Expedition had the following dimensions: — 
Length. Wultli. 
Apiiroximate number 
of segments. 
Condition of 
posterior region. 
68 mm. . 3 mm. . 300 or more . Clusters of more 
segments. 
than 50 stolons. 
It is seen that a complete worm varies greatly in length 
from 22 to 94 mm., and contains 140 to 356 segments. In most 
of the specimens, as the table shoAvs, there is present a tail 
of smaller and less developed segments. In II this is 
extremely rudimentary, though even then containing thirty 
segments or more. The figure here given of it (P). 23, fig. 1) 
shows that these segments are less developed as traced back- 
wards to the posterior end where ])roliferation takes place and 
new segments are added. In the development of the para- 
