My last post on the Digital Library of India was mainly incidental but an interesting find there was two volumes (missing one though) of William Swainson's book on the natural history and classification of the birds. It is a remarkable book, outdated for uses than historical, but still worth examining.

It is remarkable for giving a first hand account on how ornithologists saw patterns in the world around them in that period well before Darwin. One of these was the Quinarian classification. The quinarians believed that nature had been designed and that the Creator had chosen the magic number 5 in the grand plan. After all why else did most of us have five fingers on each hand or most flowers (at least the dicots) have 5 petals. By finding this order in nature, you were not just an ornithologist, but a devoted natural theologist who could see the signature of the Creator. Swainson's begins :

IF elegance of form, beauty of colouring, or sweetness of voice, were peculiarities which constituted the superiority of one class of beings over another, we should unquestionably assign to birds the highest station in the scale of the animal creation. No shadow of fear mixes with those pleasurable sensations with which they are viewed; and those feelings, moreover, are heightened by the ethereal nature of the creatures themselves. In a moment they may spread their wings, launch into boundless air, and be seen no more. We almost view them as beings of a happier world, alighting upon this "dim spot called earth," more as a place of temporary rest, in their voyage through the regions of space, than as their permanent abode. They remind us of those invisible spirits of the unseen world, which, we are taught to believe, traverse the air on the wings of the wind ; who alight, but for a moment, among the sons of men, and then depart to breath a purer atmosphere. Of all unintelligent beings, they alone are gifted with a musical voice, possessing both sweetness and varied expression. Their language, in some measure, is thus intelligible even to man, inspiring him with cheerfulness or melancholy. Hence it is, that from among birds the poets have selected their sweetest themes. They are, both poetically and literally, the butterflies of vertebrated animals;

We will come back to what he means in the last bit. The philosophical foundations of quinarianism were introduced by W S MacLeay. His book can be found on the Internet Archive and remarkably, the copy that has been scanned belonged to Thomas Horsfield and was bequeathed to Frederic Moore then presumably to the East India Museum and on to the British Museum. In one place Moore notes that the margin notes in the book are by Horsfield.

Horae entomologicae : or, Essays on the annulose animals (1819)

MacLeay is very interesting in that he tries to support the entire structure by reconstructing them from more basic principles. Now this was a time when life forms were arranged in a linear scale with man at the "upper" end. MacLeay suggested that this line had to be turned to a circle. So all animals to him were made up by a circle composed of five groups - Acrita, Mollusca, Vertebrata, Annulosa, Radiata - in that order. MacLeay's saw the top level plan of life forms (which he saw merely as matter that had been organized by a vital princple) made up of two circles touching each other and indicating similarities. The stars are placeholders for groups that according to him had not yet been found !

Organized matter organized into circles (Acrita ~ lower animals, Annulosa ~ arthropods, Radiata ~ echinoderms)

Each group then was divided again into smaller circles each again with five groups. Working on in this way and dealing with exceptions and so on he finally reaches on page 318 with this.

He then goes on to show how his view of the world can be shown to be geometrically isomorphic with Lamarck's branching diagram of groups - " Now this tabic of affinities which is given in page 457, vol. i. of the Histoire Nat. des Animaux sans Vertebres, however confused it may appear, or subramose, as it is termed by Lamarck, coincides with the tabular view which I have laid before the public in the preceding part of this chapter." and further goes on to say that "a progression of some sort does exist, neither believer nor atheist will deny ..."

MacLeay's "province" being in entomology, he then gives the plan of arthropods as :

And to further prove his point he comes up with the idea of analogies (similarities between groups at common positions on contiguous circles) - noting for instance that the Araneidea and the Lepidoptera were similar in the ability to spin silk !

Whatever it was, his work was to have a considerable influence on people in other "provinces" such as Swainson with his birds. He finds the analogy that was waiting to be found - "The feathers of birds, soft and imbricate, are perfectly analogous to the down upon the wings of butterflies, and both are disposed in the same manner." Swainson created five groups within the birds which he called the "Orders".

The Raptorial (The birds of prey - with retractile claws like that of the cats !)
The Incessorial (most passeriformes)
The Natatorial (swimmers)
The Grallatorial / Tenuirostral (Waders)
The Rasorial / Scansorial (fowl)

Like a good quinarian he gets around breaking each of his orders into 5 sub groups. The raptors he breaks into vultures, falcons and owls. Of the two he is unable to find, one he assigns to - wait a minute - the dodo ! Anyway he is convinced for he can further find those perfect analogies that ought to exist.

The Avocet compared to a racoon Nasua !

The influence of quinarianism was great, with T.C.Jerdon following it in his Birds of India (1862) in spite of Darwin's publication. He was however following a list by George Gray. A reviewer (unidentifiable) in the 1864 Quarterly Journal of Science noted that:

Dr. Jerdon, however, seems to take a very candid view of Mr. Darwin's theory on other points, though he is of opinion that that distinguished naturalist, "perhaps, lays too much stress on external and fortuitous circumstances as producing varieties, and not enough on the inherent power of change."

and finally concludes that

In thus following the phantasies of Kaup, and the mad vagaries of Bonaparte (in his latest writings), we cannot believe that Dr. Jerdon has acted well for his own reputation, nor wisely as regards the class of readers for whom his volumes are specially intended.

Old books, even those that are demonstrably inaccurate, are still worth examining. In going through Swainson's work I found a statement that the only bird with a true "horn" was Palamedea. A little searching identified the bird as the Horned Screamer. It turns out, interestingly, that this horn is not a feather quill but a peculiar cornified structure arising from the skull, which, unlike a feather grows continuously.

PS: For a more sympathetic reading and view of Quinarianism - see:
Novick, Aaron (2016) On the Origins of the Quinarian System of Classification. Journal of the History of Biology 49(1):95-133.

Further reading