some Meduscee from Japan. 617 
circular ; its attached edge follows the loops of the circular 
canal. ‘The breadth of the velum at the angles of the loops 
is 7 millim., and midway between them, 5 millim. 
The gastric peduncle is a cuboidal mass about 15 millim. in 
breadth and height, with rounded radial angles separated by 
interradial grooves, 7. e. it is quadrifoliate on transverse 
section. ‘T'wo of the segments are prolonged each into a 
conical stalactitic prolongation about 20 millim. in length, 
round which are wound the radial canals and gonads. 
Probably this asymmetry is abnormal, the normal arrange- 
ment presenting four prolongations, one in each radial plane. 
The stomach is 21 millim. in length, the breadth at the 
base being 5 millim. and at the mouth 15 millim. At each 
of the four radial angles is a thick muscle-band, which forms 
a rounded ridge extending from base to orifice. The four sides 
present many transverse folds. Probably this organ, which 
is well within the mouth of the umbrella, is capable of being 
extruded considerably beyond that orifice. The base of the 
stomach, which projects slightly into the peduncle, shows four 
radial lines meeting at the centre, these lines being furrows in 
continuation of the radial canals. 
The Gastro-vascular Canals. 
(2) The proximal unbranched portions with gonads. The 
four radial canals pass from the base of the stomach and 
proceed across the lower surface of the peduncle. Where the 
peduncular prolongations occur, the canals form transversely 
meandrine folds around them from base to apex and down 
again, and then continue on as similar folds on the radial 
aspect of the peduncle till they reach the branched gonad-free 
portion of the radial canals. At the apices of the prolonga- 
tions, the loops arising from the folding are wound spirally 
round. 
Where the peduncular prolongations do not exist the canals 
form transverse folds on the distal surface of the peduncle. 
(6) The distal branched portions without gonads. The 
proximal join the distal portions a little beyond the base of 
the peduncle. The canals are pinnately and alternately 
branched. At first the lateral branchlets are very close 
together, straight, at right angles to the main canal, and either 
unbranched or branched only at their ends; they are given off 
at gradually increasing distances, and progressively make 
angles of trom 90° to 60° with the maincanal. A few of the 
secondary branches change their lateral course and continue 
in a longitudinal direction, thus filling the proximal three 
fourths of the interradial regions. The ends of the vessels 
are club-shaped and blind, there being no anastomoses. 
