1869. ] SENATE—No. 60. 9 
homologies are circumscribed within the type of Radiates, and 
can by no means be extended beyond it; so that it may be said 
that the structure of Radiates is sui generis incompatible with 
the idea of any genetic relation between that and any other 
type of the animal kingdom. I also showed that the embryonic 
growth of all these animals is conformable, even the seemingly 
bi-lateral symmetry of the larval form of the Echinoderms, 
upon which Miller insisted so tenaciously, being as truly a 
radiate structure in its typical character as the Spatangoids, 
which also seem bi-lateral. I also compared the succession of 
this type in time with the growth of its present representatives 
in their embryonic condition, and carried out this illustration 
especially for the Crinoids; showing that in its successive 
transformations the Comatula passes through stages which, 
from their resemblance to the full grown Crinoids of earlier 
ages, I designated as the Cistidian, the Pentremitian, the Plat- 
yerinian, the Pentacrinian, and the Comatuline stages of growth. 
These phases of development coincide with the order of suc- 
cession of the types of the same name in the geological ages. 
It was farther shown that even the Ophiurans, the Aste- 
rians and the Echinoids have also their Crinoidal stages of 
growth, while their earliest embryonic forms recall in like man- 
ner the Polyps and Acalephs. Beside these courses of lectures 
Dr. Hagen has been training a few special students in ento- 
mology, and I have directed the private exercises in other 
departments. 
As in the preceding year, Mr. Allen has had general charge 
of the Mammalia and Birds, and, as may be seen from his 
special report, he has greatly improved the condition of the 
collections entrusted to him. But the work is too extensive 
for one person, and I hope to divide it during the present year. 
The collection of Reptiles has not been placed under the care 
of a special assistant during the past year. It is in a safe state 
of preservation, and for the distribution of specimens into sep- 
arate jars, according to their species, I have thought it best to 
await the return of the numerous specimens entrusted to Pro- 
fessor Cope for identification. For the Batrachians, however, 
this task of division and distribution is already begun, and is 
going on under the charge of my son, Alexander Agassiz. 
2 
