A letter concerning deep-sea dredgings, addressed to Professor Benjamin Peirce, Superintendent United States Coast Survey / by Louis Agassiz.

Date:
[1871?]
Catalogue details

Licence: Public Domain Mark

Credit: A letter concerning deep-sea dredgings, addressed to Professor Benjamin Peirce, Superintendent United States Coast Survey / by Louis Agassiz. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    2/6 (page 50)
    expect from the greater depth of the ocean representatives resembling those types of animals which were prominent in earlier geological 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 per- ception of what I may anticipate, I make the following specific statement. It lies in the very nature of these animals thdt, among vertebrates* neither Mammalia nor Birds can exist in deep waters, and if any Rep- tiles exist there, it could only be such as are related to the extinct types of the Jurassic periods, the Ichthyosauri, Plesiosauri, and Ptero- dactyles; but even of these there is very little probability that any of their representatives are still alive. Among the fishes, however, I ex- pect to discover some marine representatives of the order of Ganoids of both the principal types known from the secondary zoological period, such as Lepidoids, Sauroids, Pycnodonts, Ccelacanthes, Amioids, and *Glyptolepis-like species may even be looked for. Among Selachians some new representatives of Cestraciontes or Hybodontes may be forthcoming, connecting 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 Chimseroids we may expect some new genera more closely related to the extinct types of that family than those now living. Among ordinary fishes I take it for granted that Beryx genera may be added to our list, ap- proaching perhaps Acanus, or rather Sphenocephalus; also types allied to Istieus, to Anenchelum, and to Osmeroides, Elops, and Argentina. Dercetis and Blochius may also come up. Species of all classes of the animal kingdom which have been very rarely met with by fishermen and naturalists are likely to be found in the deepest waters, in which neither hooks nor nets are generally lowered. Nothing is known con- cerning the greatest depth at which fishes may live. Upon this point I hope to obtain positive data. The Mollusks will, no doubt, afford a rich harvest of novelties, among which some may be of the deepest zoological interest. It stands to reason that a variety of Nautiloid Cephalopods may be discovered when Nautilus proper and Spirula are so rarely found alive, and among new forms there may be those combining characters of Argo- nauts with features of Nautilus; some may even be coiled up like Tur- rilites. Belemnitic Squids would appear natural. Among Gasteropods