40 FOSSIL MEDUSA. 
Dr. Robert P. Bigelow on the development of Cassiopea wamachana. He 
states that it exhibited a phase of budding and fission that might aid in the 
better understanding of the fossil forms. I wrote to Dr. Bigelow, and he 
very kindly sent me his notes and original drawings for examination. 
These show that in the seyphostoma larvee the process of budding is carried 
on by the formation of a swelling on one side of the calyx just above 
where it tapers into the stem. The swelling increases in size, becoming 
hemispherical and then elongating. As it elongates a constriction appears 
close to the body of the seyphostoma; the constriction deepens as the bud 
alters its shape, so as to cut off the lumen of the bud from the digestive 
cavity of the seyphostoma, leaving a pear-shaped body attached to the 
seyphostoma by a very slender neck of jelly covered by the ectoderm. 
Sometimes a second bud starts in exactly the same place as the first before 
the latter drops off. As soon as it is free the bud becomes a planula-like, 
free, swimming larva. The point of interest in relation to the growth and 
subsequent dropping off of the bud is the fission-like process by which it 
secures its freedom from the parent larva. It is not fission in the sense of 
fission in Gastroblasta raffaeli, but it is suggestive of a type of fission that 
may be represented in Cambrian meduse by the growth and cutting off of 
portions of the body of the medusa, as illustrated by Laotira cambria. 
In speaking of fission among the hydroids, Dr. Allman states that, 
while budding constitutes a highly characteristic and all but universal 
phenomenon among the Hydroida, multiplication by spontaneous fission 
occurs, although it is rare and exceptional. He mentions an instance 
described by Kolliker, and describes one that came under his own imme- 
diate observation. It occurred in a campanularian hydroid, Schizocladium 
ramosum.” Stating the peculiarities of the species, he says that it is a pro- 
fusely branched form, and that besides the ramuli which support the 
hydranths, others are developed in abundance from all parts of the hydro- 
caulus. These commence just like the ordinary ramuli, as offshoots from 
the hydrocaulus, and consist as usual of a continuation of the ccenosare 
by a chitinous perisare. Unlike the ordinary branchlets, however, they 
never carry ahydranth. After the entire ramulus has attained some length 
1 Professor Brooks thinks that this species may be identical with the Cassiopea frondosa which 
was somewhat imperfectly described by Agassiz. 
2A Monograph of the Gymnoblastic or Tubularian Hydroids, by George James Allman (a pubil- 
cation of the Ray Society), Part I, 1871, p. 151. 
