MUSEUM OF COMPARATIVE ZOOLOGY. 219 
vessel which connects this radial system of tubes with the cavity of the axis of 
the colony. The bell margin has a marked velum and is destitute of tentacles. 
The sperm is found in the inflated proboscis, which fills almost the whole bell- 
cavity. This receptacle is in older male bells, and in those especially which 
are found near the extremity of the polyp-stem, of a milk-white color. The 
spermatozoa have a rounded head and small vibratile tail. The clusters of 
female bells which occur with the male have a similar attachment, and are also 
campanulate, resembling those of Agalma. Each bell carries a single ovum. 
Individual eggs and bells voluntarily separate from the attachment to the 
colony, and the latter live for some time free in the water. The ova of Nano- 
mia can easily be seen by the unaided eye, as they float about in the water in 
which a parent Nanomia is captive. 
A method of collecting the ova is to allow the Nanomia to remain quiet for 
some time in a glass jar. This jar contained about three gallons of water, and 
was so placed on a table that one could see through its sides, the window 
or source of light being on the opposite side of the jar. In this way the 
ova could readily be distinguished in the water, and after a few hours they 
rise to the surface. When they are seen floating at different depths in the 
water, it is possible to pick them out one by one with a pipette. When the 
ova rise to the surface it is more convenient to skim them off by means of 
a watch-crystal, or some similar shallow receptacle. 
Development. — The development of the older larvae of Nanomia, after the 
formation of the float, has been well described by A. Agassiz in his account 
of the animal, to which reference has already been made. He considers that 
there are two methods of development, one from‘the egg, and the other by 
budding from the parent colony. His figures are mostly from stages which he 
regards as formed by the latter method, and are of larve after the float has 
already formed. 
It is certainly an exceptional method of growth of new colonies of Siphono- 
phores to find the young budding from the parent, and new observations are 
desirable to determine the details of such growth. There is no known genus 
which resembles Nanomia in this respect, and all other genera, whose embry- 
ology is at present known, reproduce new colonies by ovulation alone. The 
following observations have a bearing on the origin of the larva of .Nanomia, 
although they leave the important question in doubt. 
A minute comparison of the float of the parent colony with the “ oil glob- 
ule” of one of the tasters was made, in order to detect differences and resem- 
blances, if any, between them. While it was found that there are marked 
differences in these two structures, I could not say that the differences would 
prevent the one being a development of the other. Still, I have not been able 
to persuade myself that such is the case. I have repeatedly found the tasters 
with their oil globules detached from the parent axis, but all attempts to raise 
these into older stages similar to those figured by A. Agassiz have failed. 
There is one point in which there is a great difference in the tasters which I 
