CHAIN OF CYCLOSALPA AFFINIS 429 
between the two wheels. The color shot out through the small 
vessels to the peduncles of the zooids still remaining in contact. 
It went throughout the vessels of the peduncles of the zooids but 
stopped cleanly at the edge of the peduncle. No zooids whose 
connection with the main vessel had been lost showed any touch 
of the color. However, the wheel was again examined about fif- 
teen minutes later. The stained zooids had died and dropped 
away from the wheel, the peduncle dropping away with the zooid. 
A slight stain was found around the papillae of the peduncles of 
one or two of the other zooids where they had come in contact 
with the stained ones. We conclude that there is no direct vascu- 
lar connection here but that there is possibly some interchange by 
absorption through the thin ectoderm. Another injection was 
made in the peduncle of one of the zooids in a wheel. ‘The color 
flowed throughout the peduncle and into the zooid but did not 
enter other zooids of the wheel. We therefore seem driven to con- 
clude that the blood supply is not a factor in the size differentiation 
of the zoords of a wheel. 
4. Unltkelthood that the wheel arrangement of the zoorids in Cyclo- 
salpa has, as believed by Brooks, anything to do with the 
position of the four first blastozooids of Pyrosoma 
Brooks was firmly convinced that the radial, or wheel arrange- 
ment of the asexually produced zooids in Cyclosalpa is homolo- 
gous with the radial disposition of the first four blastozooids 
of Pyrosoma. This he regarded as one of the strongest evidences 
of the close relationship between the two genera. Thus he says 
(Brooks 793, p. 133): 
The opinion that Salpa and Pyrosoma are closely related does not 
however, rest upon superficial resemblances, but upon their fundamental 
identity of structure, although one of the details, the resemblance in their 
asexual multiplication, is so complete as to be almost enough in itself 
to establish their affinity. 
The same view he expresses with only a little less assurance in 
several other connections. We had no thought, in entering upon 
