objects of natural history, in the hope that he might gain thereby
a wider insight. But he would not listen to it; he said he had
enough to do with his Vermine.

My brother writes me that my box has arrived in Neuchatel. As I am
going there soon I will take it then. I rejoice in the thought of
being in Neuchatel, partly on account of my brother, Arnold
(Guyot), and other friends, and partly that I may study the fishes
of our Swiss lakes. The species Cyprinus and Corregonus with their
allies, including Salmo, are, as you know, especially difficult. I
will preserve some small specimens in alcohol, and, if possible,
dissect one of each, in order to satisfy myself as to their
identity or specific variety. As the same kinds have received
different names in different lakes, and since even differences of
age have led to distinct designations, I will note all this down
carefully. When I have made it clear to myself, I will send you a
catalogue of the kinds we possess, specifying at the same time the
lakes in which they occur. As I am on the chapter of fishes, I will
ask you:

1. What are the gill arches?
2. What the gill blades?
3. What is the bladder in fishes?
4. What is the cloaca in the egg-laying animals?
5. What signify the many fins of fishes?
6. What is the sac which surrounds the eggs in Bombinator obstetricans?

. . .Tell Dr. Leuckart I have already put aside for him the
Corregonus umbla (if such it be), but can get no Silurus glanis.