256 General Notes. 
inertia of reconstruction. An Oxydromus grandis had from 40,000 
to 50,000 descendants while a pair were indulging in a single conju- 
gation. It is a source of destruction, not of the multiplication -of 
individuals. 
The riddle was solved by a long series of careful observations. 
In November, 1885, M. Maupas isolated a Stylonychia pustulata, 
and observed its generations until March, 1886. By that time there 
had been 215 fissiparous generations. But at that time the colony 
gave in; the individuals had lost the powers of nutrition and repro- 
duction. Individuals removed at various stages, however, had 
conjugated with individuals of a different origin. The same 
conjugations had been effected with members removed to other 
families. This was done till the 130th generation, and till then all 
the conjugations were fertile. About the 180th generation individ- 
uals of the same family which had not hitherto been in contact 
with one another began in despair to conjugate. The results, how- 
ever, were nil ; the conjugates did not even recover from their forlorn 
hope. Other cases are related. . 
The result is evident. The process is essential for the species. 
The life runs in developmental cycles of multiplication by division, 
=- which are strictly limited. If conjugations with unrelated forms 
do not then occur the life ebbs. The sexual conjugation of the 
Ciliates is thus a rejuvinescence, as Biitschle and Engelmann main- 
tained. It is essential as a reorganization of the nucleus. After a 
` prolonged series of divisions the nucleus undergoes senile degenera- 
tion. Without conjugation death would be inevitable. The death 
is a natural one, which some would deny. Sexual conjugation 18 
the necessary condition of their “eternal youth and immortality.” 
GERMINAL Layers or Loiiao.—Mr. S. Watase has been 
studying the development of Loligo pealei. He finds that, owing 
to the immense amount of food yolk present, the gastrulation 18 
masked, and that the mesoderm is formed before the endoderm 1s 
fully outlined. He traces the origin of the ink-bag and rectum 
from the proctodeal invagination, while the stomodeal inpushing 
gives rise to radula sac, salivary glands, and the digestive glands 
or “liver.” The endoderm is concerned only in forming a yolk 
membrane, and Mr. Watase thinks it wholly disappears, taking no 
part in the structure of the adult organs, the alimentary tract being 
formed solely of stomodeal and proctodeal invaginations. 
THE SPONGE SHRP, ALPHEUs.—Mr. F. H. Herrick con- 
tributes three articles on Alpheus to No. 63 of the John Hopkins 
