Vou. 2] Ritter—The Pelagic Tunicata. 
On 
On 
trally, and sixth bending abruptly forward to terminate on a level 
with the fifth. Ninth inclining forward on each side to touch 
the eighth tangentially, then bending sharply back to cross the 
tenth, so that on the median ventral line ninth is behind tenth. 
Three bands in dorsal lip of branchial orifice, the first divided 
into a broader and narrower portion, the second trending broadly 
backward on ventral side to become confluent with second body 
muscle; third joining second behind angle of orifice. Second 
muscle of ventral lip trending sharply backward laterally to ter- 
minate at the crossing of the second upper lip and first body 
muscles. A longitudinal band on each side extending forward 
from the second body band to angle of orifice. Endostyle rather 
slender, and with a gentle dorsal curvature near its anterior end, 
extending from midway between the second ventral lip and the 
first body muscle, to the seventh muscle. Guill of usual form and 
extent, posterior termination nearly coincident with that of the 
endostyle. Ganglion considerably behind anterior termination 
of gill, and remote from hypophysis; sense organ broad _ horse- 
shoe shaped, open end forward. Hypophysis at the anterior 
termination of the gill; in the form of a twisted horseshoe with 
open end forward and slightly to the right. Intestine straight, 
extending forward above the gill nearly to the ganglion. Stom- 
ach globular, not large. Two strap lke lobes of nearly equal 
size and length given off backward from the short bend of the 
intestine. Heart slightly in front of the posterior termination 
of the endostyle, in the interval between the sixth and seventh 
muscle bands. Stolon apparently arising in front of the heart, 
extending forward in the mid-ventral line to emerge to the out- 
side through an opening between the second and third muscle 
bands. 
(b) Aggregate (sexual) generation. Pl. III, figs. 7 and 8. 
The only zooids seen of this generation were still attached to the 
stolon, and I am, consequently, unable either to describe the full 
grown animal, or to say anything positive about the whorls. 
From the fact, however, that the musculature is essentially the 
same in form and arrangement as that here described, through 
several stages preceding the one on which the description is 
based, it is safe to presume that it will be found to be practically 
