BULLETIN OF DENISON UNIVERSITY. 
155 
shell, are the salpae. All members of such a salpian chain are of the 
same shape and similarly arranged ; by taking in and forcing out wa- 
ter they move uniformly and keep step, as it were, and thus the whole 
chain rows along with serpent-like motions beneath the smooth surface 
of the sea. Besides the chains of salpae, isolated salpae also occur, 
but of two kinds. Some bear in their organs of adhesion plain trace 
of having been members of a chain ; others entirely lack any such 
trace. On the voyage from Plymouth to Teneriffe during a calm, 
Chamisso made the surprising observation, that the isolated salpae, 
which never formed part of a chain, always contain spawn which re- 
sembles the chain of salpae ; on the other hand he found in the mem- 
bers of the chain a spawn whose form corresponds to that of the isolated 
salpae. The animals which belong to a chain, and which produce 
isolated salpae, are hermaphrodites ; but the isolated salpae are neuter, 
and the chains are produced in them without fertilization by budding. 
Two generations thus alternate, one of which is propagated sexually, 
and the other asexually by internal budding, and which are 
distinguished by other marks besides. To use Chamisso’s figure : a 
salpa is not like its mother nor its daughter, but rather its sisters and its 
grand daughters.” 
‘ ‘Chamisso named this kind of propagation that by alternating genera- 
tions. So new and unheard-of did his story appear that, when he related 
it after his return in a special Latin treatise De Salpa, published 1819, 
it either remained unnoticed or was violently attacked. Meyen, later 
professor of zoology and natural history at the University of Berlin, 
who in the years ’30-32 sailed around the world as ship’s physician on the 
merchant-man Princess Louise, was so unfortunate as to meet with not 
a single isolated salpa that contained a budding chain of salpae, while 
free-swimming chains of salpae surrounded the ship in masses. In his 
doubts concerning the correctness of Chamisso’s observations he went 
so far as to assert that the free-swimming chains of salpae and the 
chain-germs, which Chamisso claimed to have found in isolated salpae, 
had nothing at all in common. On the other hand Eschricht in Co- 
