2 : DEEP-SEA DREDGINGS. 
we are likely to find in the deepest abysses of the sea, from which 
thus far nothing has been secured. 
I will not undertake to lay down the line of argument upon 
which I base my statement, beyond what is suggested in the few 
words preceding, namely, that there is a correlation between the 
gradation of animals in the complication of their structure, their 
order of succession in geological times, their mode of develop- 
ment from the egg, and their geographical distribution upon the 
surface of the globe. If that be so, and if the animal world de- 
signed from the beginning has been the motive for the physical 
changes which our globe has undergone, and if, as I also believe 
to be the case, these changes have not been the cause of the di- 
versity now observed among organized beings, then we may ex- 
pect from the greater depth of the ocean representatives resembling 
those types of animals which were prominent in earlier geologi- 
- cal periods, or bear a closer resemblance to younger stages of the 
higher members of the same types, or to the lower forms which 
take their place nowadays. And to leave no doubt that I have.a 
distinct perception of what I may anticipate, I make the following 
specific statement. 
It lies in the very nature of these animals that, among verte- 
brates, neither Mammalia nor Birds can exist in deep waters, and 
if any Reptiles exist there, it could only be such as are related to 
- the extinct types of the Jurassic periods, the Ichthyosauri, Plesi- 
osauri, and Pterodactyles, but even of these there is very little 
probability that any of their representatives are still alive. Among 
the fishes, however, I expect to discover some marine representa- 
tives of the order of Ganoids of both the principal types known 
from the secondary zoological period, such as Lepidoids, Sauroids, 
Pycnodonts, Celacanthes, Amioids, and Glyptolepis-like species 
may even be looked for. Among Selachians some new represen- 
tatives of Cestraciontes or Hybodontes may be forthcoming, con- 
necting the latter more closely to Odontaspis. I also look forward 
to finding species allied to Corax, or connecting this genus with 
Notidanus, perhaps also Jurassic-like forms. Among Chimæ- 
roids we may expect some new genera more closely related to the 
extinct types of that family than those now living. Among or- 
dinary fishes I take it for granted that Beryx genera may be 
added to our list, approaching perhaps Acanus or rather Spheno- 
cephalus ; also types all ied to Istieus, to Anenchelum, and to Os- 
