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Full text of "Contributions to the natural history of the United States of North America. Vol.1, part 1"

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PART I. OF THE FIRST VOLUME OF THE 








ONTRIBUTIO^ 







TO THE 






NATURAL HISTORY OF THE UNITED STATES 






OF 



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BY 












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A G A S S I Z 


















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I. 



ESSAY 



ON 



CLASSIFICATION 



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ESSAY 



ON 



CLASSIFICATION. 






CHAPTER FIRST. 



THE FUNDAMENTAL RELATIONS OF ANIMALS TO ONE ANOTHER AND TO THE 
WORLD IN WHICH THEY LIVE, AS THE BASIS OF THE NATURAL SYSTEM OF 



ANIMALS. 






• > 



T 



SECTION 



I. 



THE LEADING FEATURES 



ATURAL ZOOLOGICAL SYSTEM AEE 
IN NATURE. 



FOUNDED 



Modern classificat 



tl 



- ■ 

of animals and plants are based upon the peculiarities of 



structure, and this is generally 




dered as the most important- if not the 



only safe guide in our attempts to determine the natural relations which exist 

* 

between animals. This view of the subject seems to me, however, to circumscribe 
the foundation of a natural system of Zoology and Botany within too narrow limits 



. • 



to exclude from our consideration some of the most striking characteristics of the 



two 



'g 



kingdoms of nature, and to leave it doubtful how far the 



* 

gement 



thus obtained is founded in reality, and how far it is merely the expression of our 
estimate of these structural differences. It has therefore appeared to me appropriate 
to present here a short exposition of the leading features of the animal kingdom as 



introduction to the embryology of the Chelonians 



types among Vertebrata, 
standard of comparison 
and the 



of the most extraordinary 



would afford a desirable opportunity of establishing 



a 



between the changes animals 




durin 




their growth 



permanent characters of full grown individuals of other types, and perhap 



of showing also what other points 



beside structure might with advanta 



ge be consid 







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4 



ESSAY ON CLASSIFICATION. 



Part I. 






ered in 



g 



the manifold relations of animals to one another, and to the 









orld in which they live, upon which the natural system may be founded 



In considering these various top 



I shall of 



ty have to discuss many 



questions bearing upon the very origin of organized beings, and to touch upon many 
points now under discussion among scientific men 
versy as much as possible, and only try to render the 



I shall, however, avoid contro- 



of my 



studies and 



... 



clear a manner as I possibly can in the short space I feel justified 



meditations in as 

in devoting to this subject in this volume. 
There is no question in Natural History 



which more diversified opinions are 



entertained than respecting classification 



not that naturalists disag 



as 



to the 



ty of some sort of arrangement in describing animals or plants, for since 
has become the object of special studies, it has been the universal aim of all 



naturalists to 



g 



the objects of their 



g 



in the most natural order 



possible, and even BufFon, who began the publi 



of his 



g 



Natural History 



the existence in nature of any thing like a system, closed his work 



by denying! 

grouping the birds according to certain general f< 




exhibited in common 



by 



many of them 



It is true authors have differed in their estimation of the characters 



which their different arrangements 



founded: it is equally 



* 

that they ha\" 



not viewed their arrangements in the same light, some having plainly acknowledged 
the artificial character of their systems, whilst others have urged theirs as the true 



expression of the natural 



which 



between the objects themselves 



But 



whether systems were presented as artificial or natural, they have, to this day, been 
considered generally as the expression of man's understanding of natural objects, and 

■ * 

not as a system devised by the Supreme Intelligence, 



and manifested in 



these 



obj 



i 



h 



There is only 



■ 

point in these innumerable systems 



which all seem to mee 



with all their pecn 



namely, the existence in nature of distinct species, persistin 

liarities, for a time at least, for even the immutability of species has been questioned 
Beyond species, however, this confidence in the existence of the divisions g 
admitted in zoological systems diminishes greatly. 



erall 



v 



With 



ipect to g 



we find already the numb 



of the naturalists wl 



1 The expressions constantly used with refer 



.• - 



;' 



■ T - 4 ^« j. T 

ence to genera and species and the higher groups 
in our systems as : Mr. A. has made such a species 
a genus ; Mr. B. employs this or that species to form 
his genus; and in which most naturalists indulge 
when speaking of their species, their genera, their 
families, their systems, exhibit in an unquestiona- 



own making, which can, however, only be true in so 



far as these groups are not true to nature, if the 
views I shall present below are at all correct. 

2 Lamarck (J. B. de) Philosophie zoologique, 
Paris, 1809, 2 vols. 8vo. ; 2de edit., 1830. — Powell 
(The Rev. Baden) Essays on the Spirit of the In- 
ductive Philosophy, etc., London, 1855, 1 vol. 8vo. 



ble light the conviction that such groups are of their Compare, also, Sect. 15, below. 



■■■H 




- ■ ^H V'BI*' ***r*# 





Chap. I. 



FUNDAMENTAL RELATIONS OF ANIMALS. 



5 







accept them 

b elief that 



natural divisions much smaller, few 



g 



have 



of them having expressed a 



as distinct an existence in nature 



families, orders, classes 



as species, and as to 



any kind of higher divisions, they seem to be 



considered 



convenient device 



in- 



framed with the view of facilitating the study of 



innumerable objects, and of grouping them in the most suitable manner. 



ference with which this part of our 



The indif- 
generally treated becomes unjustifiable. 



considering the pro 



which Zoology in general has made of late. 



It 



matter 



of consequence, whether g 



are circumscribed in our systematic works within 



the 



© 



or those limits, whether families inclose a wider or more contracted 
t, whether such or such orders are admitted in a class. 



g 



of 



and what are the natu- 



ral boundaries of classes, as well as how the classes themselves are related to 



one 



another, and whether all these 



group 



considered as 



g upon 



same foun 



dation 



■ 

or not. 



Without venturing he 



re 



upon 



an 



lysis of 



systems of Zoology, the 



features of which are sufficiently exemplified for my purpose by the sys 



prominent 

terns of Linnseus and C 



1 



which must be familiar to 



ery student of natural 



history 



is 



inly a seasonable question, to ask whether the animal kingdom 



exhibits only those few subdivisions into orders and 



g 



which the Linnae 



system indicates, or whether the classes differ among themselves to the extent which 
the system of Cuvier would lead us to suppose. Or is, after all, this complicated 
structure of classification merely an ingenious human invention which every one may 
shape as he pleases to suit himself? When we remember that all works on natural 



history admit some system or other of this kind, it is certainly 



inquiry worthy 



of a true naturalist to ascertain what is the real meaning of all these divisions. 

Embryology, moreover, forces the inquiry upon us at every step, as it is impos- 
sible to establish precise comparisons between the different stages of growth of young 

» - 

animals of any higher group, and the permanent characters of full grown individuals 

■ 

of other types, without ascertaining first what is the value of the divisions, with 



which we may have to compare embryo; 
in a work chiefly devoted to Embryology 



This 



is 



my 



for introducing here 



ubject to which I have paid the 



mos 



careful attention for many years past, and for the solution of which I have made 
special investigations. 

Before, however, I proceed any further, I would submit one case to the consider- 
ation of my reader. Suppose that the innumerable articulated animals, which are 
counted by tens of thousands, nay, perhaps by hundreds of thousands 



had 



never 



made their appearance upon the surface of our globe, with one 



that, for instance 



■ 

lobster (Homarus americanus) were the 



gle 



pt 



nly representative of 






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Compare Chap. III. 






■ 




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6 



ESSAY ON CLASSIFICATION. 



Part I. 






that extraordinarily diversified type, how should we introduce that species of animals 



m our 



ystems ? Simply 



genus with one species, by the side of all the other 



with their orders, families 



family 



one species, or as 
family and one g 



a class with one order and one 



genus, or 



only one genus with 
as a class with one 



? 



And should .we acknowledge, by the side of Vertebrata 



Mollusks, and Radiata, another typ 



of Articulata. on account of the existence of 



that one lobster, or would it be natural to call him by a single name, simply 



a 



species in contradistinction to all other animals 



It was the consideration of this 



supposed case which led me to the investigations detailed below, which, I hope, may 
end in the ultimate solution of this apparently inextricable question. 

Though what I have now to say about this supposed case cannot be fully appre- 
ciated before reading my remarks in the following chapter, 1 respecting the character 
of the different kinds of groups adopted in our systems, it must be obvious that our 



lobster, to be what we see these animals are, must have its frame 



structed upon 



that very same plan of structure which it exhibits now, and if I should succeed in 



showing that there is a difference between the conce 




of a plan and the manner 



in which it is executed, upon which classes are founded in contradistinction to the 
types to which they belong, we might arrive at this distinction by a careful investi- 

as by the study of all of them, and we 



gation 



of that single Articulate as 



well 



might then recognize its type and ascertain its class characters as fully as if the type 
embraced several classes, and this class thousands of species. Then that animal has 



form, which we could 



fail to recognize, and if form can be shown to be char 



acteristic of families, we could thus determine its family. Again, besides the general 



of all the systems of org 



of the 



structure, showing the fundamental relations 

body to one another in their natural development, our 

into the study of the details of that structure in every part, and thus lead to the 



gation could be carried 



recognition of 

animal has definite relations 



what constitutes everywhere g 



characters. Finally, as this 



the surrounding world, as the individuals living at the 



time bear 
proportion 



definite relations 



one 



another 



and 



as 



as the parts of their body show definite 
the surface of the body exhibits a special ornamentation, the 



specific characters could be traced as fully as if a number of other species were at 
hand for comparison, and they might be drawn and described with sufficient accu- 
racy to distinguish it at any future time from any other set of species found after- 

In this case, then, we should have 

a class, a family, and 



wards, however closely these might be allied to it. 

M 

to acknowledge a separate branch in the animal kingdom, with 



a g 



to introduce this 



species in its proper 




in the system of animal 



But this class would have no order, if orders determine the rank as ascertained by 



. 



1 See Chap. II. 



i 






m ^ mammaaa ^ m 



. •• ' : 




■■■ 



" "* 






I 



Chap. I. 



FUNDAMENTAL RELATIONS OF ANIMALS. 



7 



the complication of structure; for where there is but one 



there is no room for the question of 



presentative of a typ 






others within the limits of the 

the class. Yet, even in this 



superiority or inferiority in comparison to 



orders being groups subordinate to the type of 



the question of the 



• 

among the other great branches of the animal 



g of Articulata as a 



o 



but it would 



kingdom would be 



open 



comparison of Articulata with the o 

and would lead to a very different result from that at which 



to our 

as the 
types would then be limited to the lobster. 



another aspect from that it now presents 



we may arrive now 



this type includes such a large number of most extensively diversified represent- 



belon 



to different classes 



be appar 



That such specul 



idle must 



any one who 



that, during every period in the history of 



globe, during the past geological ages, 1 the general relations, the numeric 

and the relative importance of all the types of the animal kingdom have been 




ever 



g until their present relations were established 



H 



then, the individuals 



of one species, as observed while 



living, simultaneously 



exhibit characters which, to 



be 



pressed satisfactorily and in conformity to what nature tells us would 



the establishment, not only of a distinct species, but also of 



require 



• 

distinct family, a distinct class, a distinct branch 



a distinct genus, a 



Is this not in itself evidence enough 



genera, families, orders, classes, and types have the same foundation 



as 



species, and that the individuals living at the time have alone 
they being the bearers not only of all these different categor 



which the natural system of animals is founded, but also of all the 



a material existence, 
of structure upon 
relations which 



animals 



the surrounding world; thus showing that species do not exist in 



different way from the higher groups 



generally believed 



The divisions of animals according to branch, class, order, family 



g 



and 



the results of our investigations into the relations of 



species, by which we express 

the animal kingdom, and which constitute the first question 

■ 

systems of Natural History which we have to consider 



w 

respecting the scientific 

■ 

seem to me to deserve the 



consideration of all thoughtful minds. Are those divisions artificial 



Are 



9 

1 A series of classifications of animals and plants, 

■ 

exhibiting each a natural system of the types known 
to have existed simultaneously during the several 



* 

of an accurate knowledge of the relative standing 
of all animals and plants, which can only be infer- 
red from the perusal even of those palseontological 
successive geological periods, considered singly and works, in which fossil remains are illustrated aJord- 

in S t0 their association in different geological forma- 



without reference to the types of other ages, would 
show in a strong light the different relations in 



tions, as in these works these 



which the classes, the orders, the families, and even formly referred to a system establ" h d 



remains are uni- 



the genera and species, have stood to one another 
during each epoch- Such classifications would illus- 
trate in the most impressive manner the importance period under consideration,. 



T 1 

upon the 
study of all animals now known, thus lessening the 
impression of their peculiar combination for the 



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X. 









8 



ESSAY GN CLASSIFICATION. 



Part I. 
























they the devices of the human mind to classify and arrange our knowledge in such 
a manner as to bring it more readily within our grasp, and facilitate further investi- 
gations, or have they been instituted by the Divine Intelligence as the categories of 

t 1 Have we, perhaps, thus far been only the unconscious 
e conception, in our attempts to expound nature, and when, 



his mode of thinking 



interp 



of 



a 



D 



- 

in our pride of philosophy, we thought that we were inventing systems of science 
and classifying creation by the force of our own reason 
reproduced in our 



have 



followed 




imperfect expressions, the plan whose foundations were laid 



and 
the 



dawn of creation, and the development of which we are laboriously studying, thinking, 

are anew intro- 



as we put together and s 
ducing order into chaos ? 



nige our fragmentary knowledge, that we 
Is this order the result of the exertions 



of human skill 



and 



genuity, or is it inherent in the obj 



jets themselves, so that the intelligent 
ily by the study of the animal kingdom 



student of Natural History is led unconsciou 

itself to these conclusions ; the great divisions under which he 

indeed but the headings to the chapters of the great book which he is reading 



me it appears indisputable that this order and 



gement of our studies 



ges animals being 

I To 

based 



upon the natural, primitive relations of animal life; those systems, to which we have 
given the names of the great leaders of our science who first established them, being 



truth but translations 



And 
the 



into human language of the thoughts of the Creator, 
if this is indeed so, do we not find in this adaptability of the human intellect t( 
facts of creation, by which we become instinctively, and, as I have said, unconsciously, 
the translators of the thoughts of God, the most conclusive proof of our affinity with 
the Divine Mind, and is not this intellectual and spiritual connection with the Almighty 

* 

worthy our deepest consideration ? If there is any truth in the belief that man is 
made in the image of God, it is surely not amiss for the philosopher to endeavor by 
the study of his own mental operations to approximate the workings of the Divine 
Reason, learning from the nature of his own mind better to understand the Infinite 
Intellect from which it is derived. Such a suggestion may, at first sight, appear irrev- 
erent. But, which is the truly humble ? He who, penetrating into the secrets of crea- 



tion, arranges them under a formula, which he proudly 



his scientific system 



he who, in the same pursuit, recognizes his glorious affinity with the Creator, and, in 
deepest gratitude for so sublime a birthright, strives to be the faithful interpreter of 
that Divine Intellect with whom he is permitted, nay, with whom he is intended 
according to the laws of his being, to enter into communion. 



• 



1 It must not be overlooked here that a system of a Creator, but merely as the expression of a 

may be natural, that is, may agree in every respect fact existing in nature, no matter how, which the 

with the facts in nature, and yet not be considered human mind may trace and reproduce in a sy stem- 
by its author as the manifestation of the 



thoughts 



atic form of its own invention. 














*i"» 



' ." 



T 




^», F* 







Chap. I. 



FUNDAMENTAL RELATIONS OF ANIMALS. 



9 






I confess that this question as to the nature and foundation of 



our 



fie 



classifications appears to me to have the deepest importance, an importance far greater 
indeed than is usually attached to it If it can be proved that man has not 



invented, but only traced this systematic 



and 



ement in nature, that these relations 



pro 



which exist throughout the animal and 



getable world have an 



intellectual, an ideal connection in the mind of the Creator, that 



pi 



crea- 



tion, which so commends itself to our highest wisdom, has not grown out of the 
necessary action of physical laws, but was the free conception of the Almiehtv 



Intellect, matured in his thought, before it was manifested 



short 



prove premeditation prior to the 



n tangible external forms 

of creation, we have done 



once and for ever, with the desolate theory which refers us to the laws of 



matter 



g for all the wonders of the universe, and leaves 



with no God but the 



monotonous, unvarying action of physical forces, binding all things to their inevitable 
destiny. 1 I think our science has now reached that degree of advancement, in which 
we may venture upon such an investigation. 

argument for the existence of an intell 



The 



g 



Creator 



generally drawn from 



■ 



1 I allude here only to the doctrines of material- for in whatever manner any state of things which 

ists ; hut I feel it necessary to add, that there are has prevailed for a time upon earth may have been 

physicists, who might be shocked at the idea of being introduced, it is self-evident that its establishment 

considered as materialists, who are yet prone to be- and its maintenance for a determined period are two 

lieve that when they have recognized the laws which very different things, however frequently they may 

regulate the physical world, and acknowledged that be mistaken as identical. It is further of itself plain 

these laws were established by the Deity, they have that the laws which may explain the phenomena of 

explained every thing, even when they have consid- the material world, in contradistinction from the or- 

ered only the phenomena of the inorganic world, as ganic, cannot be considered as accounting for the 

existence of living beings, even though these have a 



if the world contained no living beings and as if 

exhibited nothing that differed 



these livinsr 1 



g oemgs 



from the inorganic world. Mistaking for a causal 
relation the intellectual connection observable be- 



material body, unless it be actually shown that the 
action of these laws implies by their very nature the 
production of such beings. Thus far, Cross's experi- 
tween serial phenomena, they are unable to perceive ments are the only ones offered as proving such a 
any difference between disorder and the free, inde- result. I do not know what physicists may think 
pendent, and self-possessed action of a superior mind, about them now ; but I know that there is scarcely 
and call mysticism, even a passing allusion to the a zoologist who doubts that they only exhibited a 
existence of an immaterial principle in animals, which mistake. Life in appropriating the physical world 
they acknowledge themselves in man. [Powell's to itself with all its peculiar phenomena exhibits how- 
Essays, etc., p. 478, 385, and 466.] I would further ever, some of its own and of a higher order, which 
remark, that, when speaking of creation in contra- cannot be explained by physical agencies. The cir- 
distinction with reproduction, I mean only to allude cumstance that life is so deeply rooted in the inor- 



to the difference there is between the regular course 



ganic nature, affords, nevertheless, a strong tempta- 



of phenomena in nature and the establishment of that tion to explain one by the other ; but we shall see 
order of things, without attempting to explain either ; presently how fallacious these attempts have been. 



2 



1 




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■- ■ • 










10 



ESSAY ON CLASSIFICATION. 



Part I. 
















































the adaptation of means to ends, upon which the Bridgewater treatises, for example 



have been based. 1 But this does not appear to me 



the whole ground, for 



we 



that the natural 



of obi 



a final fitness of the 



universe, and thus produc 

the argument derived from the connection of org 

satisfactory, for, beyond certain limits 



upon each other should result in 

an harmonious whole ; nor does 

ls and functions seem to me more 



functions 



for 



not even true. We find organs without 
the teeth of the whale, which never cut through the gum, 



the breast in all males of the class of mammalia; these and similar organs are pr 



served in obedience to a 



certain uniformity of fundamental structure, true to the 



ginal formula of that division of animal life 



when 



essential to its mode 



of existence. 



The 



'g 



remains 



reference to a plan, 2 and might almost remind us 



not for the performance of a function, but with 

of what we often see in human 



structures, when, for instance, in 



architecture, the same external combinations are 



retained for the sake of symmetry and harmony of proportion, even when they have 



practical object. 

I disclaim every intention of introducing 



work any evidence irrelevant to 



my subj 



of supporting any conclusions not immediately flowing from 



but I 



cannot overlook nor disregard here the close connection there is between the facts 
ascertained by scientific investigations, and the discussions now carried on respecti 



the origin of organized beings, 
unscientific to believe that thinking 



And though I know those who hold 



be very 



there is an essential differ 



between 



not something inherent in matter, and that 
inorganic and living and thinking beings, I 



shall not be prevented by any such preten 



of 



false philosophy from expressing 



edit. 1837. 



1 The Bridgewater Treatises, on the Power, Wis- 
dom, and Goodness of God, as Manifested in the 
Creation : Chalmers, (Thomas,) The Adaptation of 
External Nature to the Moral and Intellectual Consti- London, 1835, 2 vols. 8vo. 



Kirby, (Will.,) The Power, Wisdom, 
and Goodness of God, as Manifested in the Creation 
of Animals, and in their History, Habits, and Instincts, 



(W 



tution of Man, Glasgow, 1839, 2 vols. 8vo. 



KlDD, 



(John,) On the Adaptation of External Nature to 



Man 



8vo. 



Whewe 



Physics considered with Reference to Natural Theol- 
ogy, London, 1839, 1 vol. 8vo. — Bell, (Charles,) 



istry, Meteorology, and the Function of Digestion, 

- 

considered with Reference to Natural Theology, Lon- 
don, 1834, 1 vol. 8vo. Compare also: Strauss- 
Durkheim, (Herc.,) Theologie de la Nature, Paris, 
1852, 3 vols. 8vo. — Miller 



Bab- 



The Hand, its Mechanism and Vital Endc 
evincing Design, London, 1833, 1 vol. 8vo. 
(Peter Mark,) Animal and Vegetable Physiology, 
considered with Reference to Natural Theology, Lon- 

— Buckland, (Will.,) Ge- 



the Creator, Edinburgh, 1849, 1 vol. 12mo. 

bage, (C.,) The Ninth Bridgewater Treatise, a Frag- 



Roget, ment, London, 1838, 1 vol. 8vo. ; 2d edit. 



don, 1834, 2 vols. 8vo. — Buckland, 

ology and Mineralogy considered witl 

Natural Theology, London, 1836, 2 vols. 8vo. ; 2d reference most fully. 



The unity of structure of the limbs of club- 
footed or pinnated animals, in which the fingers are 
never moved, with those which enjoy the most per- 
fect articulations and freedom of motion, exhibits this 









U 



_ aHHB ^ H ^_ 



■ 



» 









Chap. I. 



FUNDAMENTAL RELATIONS OF ANIMALS. 



11 



v 






my conviction that as Ion 
actually reason, I shall ( 



be shown that matter or physical forces do 



der any manifestation of thou 



as evidence of the 



existence of 



g being as the author of 



intelli 
the e: 



and 



of 



when he recognizes their natural 



such thought, and shall look upon an 
gible connection between the facts of nature as direct proof of 

tainly as man exhibits the power of thinking 



thinking God 



As I 



am 



not writing a didactic work, I will not enter here into a detailed illus- 
tration of the facts relating to the various subjects submitted to the consideration of 
my reader, beyond what is absolutely necessary to follow the argument, nor dwell at 
any length upon the conclusions to which they lead, but simply recall the leading 
features of the evidence, assuming in the argument a full acquaintance with the 

> 

whole range of data upon which it is founded, whether derived from the affinities or 
the anatomical structure of animals, or from their habits and their geographical distri- 
bution, from their embryology, or from their succession in past geological ages, and 



the peculiarities they have 



exhibited during each, 2 believing, 



as I do, that isolated and 



disconnected facts are of little consequence in the contemplation of the whole plan 



1 I am well aware that even the most eminent 



of naturalists, in Gottingen, and which have since 



investigators consider the task of science at an end, then been carried on in several pamphlets in which 
as soon as the most general relations of natural phe- bigotry vies with personality and invective. 



nomena have been ascertained. 



To many the in- 



quiry into the primitive cause of their existence 
seems either beyond the reach of man, or as be- 



2 Many points little investigated thus far by most 
naturalists, but to which I have of late years paid 
particular attention, are here presented only in an 
longing rather to philosophy than to physics. To aphoristic form, as results established by extensive 
these the name of God appears out of place in a investigations, though unpublished, most of which will 
scientific work, as if the knowledge of secondary be fully illustrated in my following volumes, or in a 



agencies constituted alone a worthy subject for their special work upon the plan of the creation. 



(See 



investigations, and as if nature could teach nothing Agassiz, (L.,) On the Difference between Pro«Tes- 
about its Author. Many, again, are no doubt pre- sive, Embryonic, and Prophetic Types in the Succes- 



vented from expressing their conviction that the 
world was called into existence and is regulated by 



sion of Organized Beings, Proceed. 2d Meeting Amer. 
Assoc, for the Advancement of Science, held at Cam- 



an intelli' ent God, either by the fear of being sup- bridge in 1849, Boston, 1850, 1 vol. 8vo., p. 432.) 

posed to share clerical or sectarian prejudices ; or Meanwhile I refer in foot notes to such works as con- 

because it may be dangerous for them to discuss tain the materials already on hand for the discussion 

freely such questions without acknowledging at the of these subjects, even when presented in a different 
same time the obligation of taking the Old Testament 



as the standard by which the validity of their re- 
sults is to be measured. Science, however, can only 



light. I would only beg leave to add, that in these 
references I have by no means attempted to quote all 
the writers upon the various topics under consider- 
ation, but only the most prominent and most instruc- 
sphere ; and nothing can be more detrimental to its tive, and here and there some condensed accounts 
true dignity than discussions like those which took of the facts in more elementary works, by the side 
place at the last meeting of the German association of the original papers. 



prosper when confining 



itself within its legitimate 



:.';..' V ... 



'•-,.- ■■■. ;■■ 



-.-' .••'.•. 



■ ■ . ■-.- 







M 









-■*. 




S* 



■ 




11 




"» 







■*- 












12 



ESSAY ON CLASSIFICATION 



Part I 



of creation, and 



without a consideration of all the facts furnished by the study 



of the habits of animals, by their anatomy, their embryology, and the history of the 
past ages of our globe, we shall never arrive at the knowledge of the natural system 
of animals. 



Let 



consider some of these topics more specially 









SECTION II 






SIMULTANEOUS EXISTENCE OF THE MOST DIVERSIFIED TYPES UNDER IDENTICAL 

CIRCUMSTANCES. 































■ • 



It is a fact which seems to be entirely overlooked by those who assume an exten- 



existence of organized beings, that 



sive influence of physical causes upon the very 

the most diversified types of animals and plants are 

tical circumstances. The smallest sheet of fresh water, every point upon the sea- 



ywhere found under iden 



shore, every acre of dry land, teems with a 



ety of animals and plant 



The 



narrower the boundaries 



are, which 



may 



be assigned 



as the primitive home of all 



these beings, the more uniform must be the conditions under which they 
to have originated; so uniform, indeed, tl 
the same physical causes could produce 



assumed 



end the inference would be, that 



the most diversified effects 



l 



To concede 



1 In order fully to appreciate the difficulty al- been provided for, if, as I believe, they were crea- 



luded to here, it is only necessary to remember how 
complicated, and at the same time how localized the 



ted as eggs, which conditions must have been con- 



formable to those in which the living representatives 

conditions are under which animals multiply. The of the types first produced, now reproduce them- 
selves. If it were assumed that they originated in 
there to a certain size, until it requires fecundation, a more advanced stage of life, the difficulties would 
that is, the influence of another living being, or at be still greater, as a moment's consideration cannot 



egg originates in a special organ, the ovary ; it grows 






least of the product of another organ, the spermary, 



fail to show, especially if it is remembered how com- 



to determine the further development of the germ, plicated the structure of some of the animals was, 

■ 

which, under the most diversified conditions, in dif- 
ferent species, passes successively through all those 



which are known to have been among the first in- 
habitants of our globe. When investigating this sub- 



feet being. 



changes which lead to the formation of a new per- ject, it is of course necessary to consider the first 

appearance of animals and plants, upon the basis of 
probabilities only, or even simply upon that of pos- 
sibilities; as with reference to these first-born, at 
least, the transmutation theory furnishes no explana- 
tion of their existence. 



I then would ask, is it probable that 
the circumstances under which animals and plants 
originated for the first time can be much simpler, 
or even as simple, as the conditions necessary for 
their reproduction only, after they have once been 
created? Preliminary, then, to their first appearance, 
the conditions necessary for their growth must have the first flora which have existed upon earth, special 



belon 






^ _ ;W 











Chap. I. 



DIVERSIFIED TYPES FOUND EVERYWHERE. 



13 







on the contrary, that these 



anisms 



may have appeared in the beginning over a 



wide area, is to grant, at the same time, that the physical influences under which 



they 



were 



specific 



the assumption that these could 



be the cause of their appearance. In whatever connection, then, the first appear- 

' it is assumed that they 



ance 



of organized beings upon 



earth is viewed, whethe 



mated within the most limited areas, 



w 

or over the widest range of their present 
natural geographical distribution, animals and plants being everywhere diversified to 



the most extraordinary extent, it is 
they subsist cannot logically be con* 




as m every 



other respect, when considering the relations 



in that the physical influences under which 

ed as the cause of that diversity. In this, 

of animals and plants to 



the conditions under which they live, or to one another, we are 



tably led to 



look beyond the material facts of the case for an explanation of their existence. 
Those who have taken another view of this subject, have mistaken the action and 

which exist everywhere between organized beings, and the physical influences 

snetic connection, and carried their mistake 



r 



under which they live 1 for a causal 



g 



far as to assert that these manifold influences could really extend to the production 



of these beings, not considering how inadeq 



such 



ence of those being; 



The 



a cause would be, and that 
gs presupposes the very exist- 
pie fact that there has been a period in the history 



of physical agents upon organized bein 



. 



relations, special contrivances must therefore have 



two questions, the influence of physical agents upon 



been provided. Now, what would be appropriate animals and plants already in existence, and the ori- 

+ 

for the one, would not suit the other, so that exclud- gin of these beings. Granting the influence of these 

ing one another in this way, they cannot have origi- agents upon organized beings to the fullest extent 

* 

nated upon the same point; while within a wider to which it may be traced, (see Sect. 16,) there 

area, physical agents are too uniform in their mode remains still the question of their origin upon which 

of action to have laid the foundation for so many neither argument nor observation has yet thrown any 
such specific differences as existed between the first 
inhabitants of our globe. 



1 See, below, Sect. 16 



light. But according to some, they originated spon- 
taneously by the immediate agency of physical forces, 
and have become successively more and more diver- 



2 A critical examination of this point may dis- sified by changes produced gradually upon them, by 
pel much of the confusion which prevails in the dis- these same forces. Others believe that there exist 
cussions relating to the influence of physical causes laws in nature which were established by the Deity 
upon organized beings. That there exist definite in the beginning, to the action of which the origin 
relations between animals as well as plants and the of organized beings may be ascribed ; while accord- 
mediums in which they live, no one at all familiar ing to others, they owe their existence to the im- 

i 

with the phenomena of the organic w T orld can doubt ; 

that these mediums and all physical agents at work is the object of the following paragraphs to show 

in nature, have a certain influence upon organized that there are neither agents nor laws 

beings is equally plain. But before any such action known to physicists under the influence and by the 

can take place and be felt, organized beings must action of which these beings could have originated • 

exist. The problem before us involves, therefore, that, on the contrary, the very nature of these be- 



mediate intervention of an intelligent Creator. 



It 



in nature 



f t 



■ ■ • ■ 



- ..*■' .*• -■. 




»- ^*- 
















n 



ss 





V 


















14 



ESSAY ON CLASSIFICATION. 



Part I 




































of our earth, now well known to geologists, 1 when none of these organized beings as 
yet existed, and when, nevertheless, the material constitution of our globe, and the 
physical forces acting upon it, were essentially the same as they are now, 2 shows that 
these influences are insufficient to call into existence any living being. 

Physicists know, indeed, these physical agents more accurately than the naturalists, 

who ascribe to them the origin of organized beings; let us then ask them, whether 
the nature of these agents is not specific, whether their mode of action is not spe- 



cific 



They will all answer, that they 



Let us further inquire of them, what 



evidence there is, in the 



pr 



state of our knowledge, that at any time these 



.? 



If I 



am 



ill, one and all 



physical agents have produced any thing they no longer do produce, and what prob 
ability there is that they may ever have produced any organized being 
not greatly mistaken, the masters in that department of science 

■ 

answer, none whatever. 

But the character of the connections between organized beings and the physical 

■ 

conditions under which they live is such as to display thought; 3 these connections 
are therefore to 



be considered as established, determined, and regulated by 



being. They must have been fixed for each species at its b 



v-^ 



•to> 



while the fact 



through 



successive generations 4 is further evidence that with 
surrounding world were also determined the relations 



their 



g 



6 



showing, therefore 



well as their family relations, and 
not only thought, in reference to 



of their permanency 

their natural relations to the 

of individuals to one another 

every higher grade of affinity^ 

the physical conditions of existence, but such comprehensive thoughts as would 
embrace simultaneously every characteristic of each species. 

Every fact relating to the geographical distribution of animals and plants might 
be alluded to in confirmation of this argument, but especially the character of every 



















■ 

in^s, and their relations to one another and to the to contain fossils at all, there is a variety of them 
world in which they live, exhibit thought, and can 



found together. (See Sect. 7.) Moreover, the simi- 



therefore be referred only to the immediate action larity in the character of the oldest fossils found in 

of a thinking being, even though the manner in different parts of the world, goes far, in my opin- 

which they were called into existence remains for ion, to prove that we actually do know the earliest 
the present a mystery. 



types of the animal kingdom which have inhabited 



1 Few geologists only may now be inclined to 



our globe. This conclusion seems fully sustained by 



believe that the lowest strata known to contain fos- the fact that we find everywhere below this oldest 
sils, are not the lowest deposits formed since the set of fossiliferous beds, other stratified rocks in 
existence of organized beings upon earth. But even which no trace of organized beings can be found. 



those who would assume that still lower fossiliferous 
beds may yet be discovered, or may have entirely 
disappeared by the influence of plutonic agencies, 

(Powell's Essays, etc., p. 424,) must acknowledge 
the fact that everywhere in the lowest rocks known 



2 See, below, Sect. 21. 

8 See, below, Sect. 16. 

4 See, below, Sect. 15. 

6 See, below, Sect. 17. 

6 See, below, Sect. 6. 






















Chap. I. 



DIVERSIFIED TYPES FOUND EVERYWHERE. 



15 



fauna and every flora upon the surface of the globe 



animals and plants 



the perusal 



H How 

the same region may be. 



g 



special works upon the 



t the diversity of 
be ascertained by 



gy and Botany of different 



from special treatises upon the geographical distribution of animals and plants 



I 



need, therefore 



enter into 



details 



discussed more fully below 



upon this subject, espe 



is 



2 



It might, perhaps, be urged, that animals livin 



conditions 



and exhibiting structural peculiarities apparently resulting from these conditions, such 
as the blind fish, 3 the blind crawfish, and the blind insects of the Mammoth Cave 
in Kentucky, furnish uncontrovertible evidence of the immediate influence of those 



ptional conditions upon the 



"g 



of vision. 



If this, however, were the case, 



how does it happen that that remarkable fish, the Amblyopsis speleeus, has only such 



remote affinities 



other fishes 



Or were, perhaps, the sum of influences at work 




make that fish blind, capable also of devising such a combination of structural char 



ac- 



ters as that fish has 



common 



all other fishes, with those peculiarities which 
^es not, rather, the existence of a rudimentary 
eye discovered by Dr. J. Wyman in the blind fish show, that these animals, like all 



» 

at the same time distinguish it? 



D 



others, were created with all their peculiarities by the 
rudiment of eyes left them as a remembrance of the 



fiat of 



g 



the great typ 



which they belong? Or will, perhap 



Almighty, and this 
an of structure of 
one of those natural- 




know so much better than the physicists what physical forces may produce 



and that they may produce, and have produced every living b 



a 



known 



also to us why subterraneous caves in Ame 



pi 



and blind 



produce blind fishes, blind Crustacea, 



forms, with a number of 



while in Europe they produce nearly blind reptiles? If there is 

anguinus, 
n, one of 



no thought in the case, why is it, then, that this very reptile, the Proteus 



ptiles living in North America and in Jar 



1 Schmarda, Die geographische Verbreitung der 



sonnee, 2 vols. 8vo., Paris, 1855. References to 



Thiere, 3 vols. 8vo. Wien, 1853. — Swainson, (W.,) special works may be found below, Sect. 9 
A Treatise on the Geography and Classification of 
Animals, London, 1835,1 vol. 12mo. — Zimmekmann, 



2 See, below, Sect. 9. 



Wy 



— 7 

(E. A. G.,) Specimen Zoologise geographies, Quadru- from a Cave in Kentucky, Silliman's Jour. 1843 
pedum domicilia et migrationes sistens, Lugduni-Ba- vol. 45, p. 94, and 1854, vol. 17, p. 258. — Tel 



tav., 1777, 1 vol. 4to. — Humboldt, Essai sur la geo- 



Mam 



graphie des plantes, 4to., Paris, 1805 ; and Ansichten muthhohle in Kentucky, in Muller's Archiv 1844 

Tellkampf, (Th. G.,) Beschreibung eini- 



der Natur, 3d edit., 12mo., Stuttgardt and Tiibin- 



p. 381. 



gen, 1849. — Robert Brown, General Remarks on ger neuer in der Mammuthhohle aufgefundener Gat- 



the Botany of Terra Australis, London, 1814. 

Schotjw, Grundziige einer allgemeinen Pflanzengeo- vol. L, p. 318. 

graphie, 1 vol. 8vo., with atlas in fol., Berlin, 1823. Blind Fish of 



WlE 



Agassiz, (L.,) Observations on the 



Mamm 



Alph. de Candolle, Geographie botanique rai- nal, 1851, vol. 11, p # 127. 




\ 







.-,'.-..■ 



• - ■ 

1 






■» r 



•w ■ »*»* 























16 



ESSAY ON 



S 



Part I 






















the most natural series known in 



the animal kingdom, every member of which 



exhibits a distinct grade * in the scale 
After we have freed our 



ourselves from, the mistaken impression that there may be 
some genetic connection between physical forces and organized beings, there remains 



field of investigation to ascerta 
and within their natural limits 



the true relations between both 



their full 



A mere reference to the mode of breathing 



of different type 



■ 

of animals, and to their 



8 



of locomotion, which are more 



particularly concerned in 



these relations, will remind every naturalist of how g 



importance in classification is the structure of these parts, and how much better they 
ght be understood in this point of view, were 



gans more 



ely studied 



the different structures of these 
their direct reference to the world in which ani- 



mals live 
name of 



If this had been done, we should no longer call by the same common 



« 



and 



g 



"g 



so different as the locomotive appendag 



of the 



insects and those of the birds? We should no longer call lungs the breathing 



avity of 



well as the 



pipes 



of mammalia, birds, and reptiles? A g 



reform is indeed needed in this part of our 



and no study can prepare us 



better for it than the 



g 



of the mutual depende 



of the structure of 



animals, and the conditions in which they live 










SECTION III 






REPETITION OF IDENTICAL TYPES UNDER THE MOST DIVERSIFIED CIRCUMSTANCES. 












As much as the diversity of animals and plants living under identical physical 

:e of organized beings from the medium in which 



conditions, shows the independen 



they dwell 



far 



their 



g 



is concerned, so independent do they appear ag 



from the same influences when we consider the fact that identical typ 

> * 

where upon earth under the most diversified circumstances 



various 
cosmic 



influences and conditions of existence under the common appellat 



every 



If we sum up all these 

on of 



influences, or of physical causes, or of climate in 



the 



idest sense of the 



word, and then look around us for the extreme differences in that respect upon 



the 



whole surface of the globe, we find still the most similar, nay identical typ 



allude here, under the expression of type 
word) living normally under their action. 



the most diversified 



ptations 



(and I 
of the 



There 



structural difference between 



the herrings of the Arctic, or those of the Temperate zone 



or those of the Trop 





See, below, Sect. 12 



2 See, below, Sect. 16. 




















Chap. I. 



IDENTICAL TYPES FOUND EVERYWHERE. 



or 



those of the Antarctic regions; there are not any more between 



wolves of the most distant parts of the globe. Moreover, if 

the specific differences existing) 

between these differences and the cosmic influences nnder which they 



between them were insisted 



which would at the same time account for the independence 



in general 



Or 



other words, how could it be assumed 



would produce specific differences, they would at the same 

identity, family identity, ordinal identity, class identity, typical identity? Identity 



structure 



ani- 



every thing that is truly important, high, and complicated 
mals, produced by the most diversified influences, while 
extreme physical differences, considered as the cause of the existence of these ani- 
mals, would produce diversity in secondary relations only ! What logic ! 

the contrary, that organized beings exhibit the most 




were any, and 



could 



relation 



be pointed 



structure 



causes 



produce g 



D 



not all this show, on 



astonishing independence of the physical 



under which they 



independ 



ence so g 



that it can 




these physical causes as well 



be understood as the result of a power governing 
existence of animals and plants, and bringing all 



harmonious relations by adaptations which never can be considered as cause and 



effect 



When naturalists have 



gated the influence of physical 



causes upon living 



they have constantly overlooked the fact that the features which are thus 



beings, 

modified are only of secondary importan 

that n( 



in the life of animals and 




and 



ther the plan of their structure, nor the 



pi 



of that struc- 



ture, are 



affected by such influences 



What, indeed, are the parts of the body 



which are, in any way, affected by external influences 



Chiefly those which are in 



immediate 



with the 



world, such as the skin, and in the skin chiefly 



layers, its color, the thickness of the fur, the 



of the hair, the feather 



and the scales; then the size 
the quality and quantity of the food 
they live in waters or upon a soil 
rapidity or slowness of the gn 
the seasons, in different years 



of the body and its weight, as far as it is dependent 



the thickness of the shell of Mollusks, when 



g 



more or less limestone, etc. 



The 



is 



also influenced 



measure by the course of 



so is also the fecundity, the duration of life, etc 



But all this has 






do with the essential characteristics of animals 



A book has yet to be written upon 



the 



dependence of organized b 



gs of 



physical causes, as 



most of what 



is generally 



bed to the influence of physical 



agents 



upon 



ganized beings ought to be considered as a connection established 



between them in the general plan of creation. 







' 




1 Innumerable other examples might be quoted, naturalists ; those mentioned above may suffice for 
which will readily present themselves to professional my argument. 

3 






*». 



- ■ .- 



I • I. • 

. - ... 






[ 






""*•- 





^* 




V 











v., *v 



sn: 




>£ 









18 



ESSAY ON CLASSIFICATION 



Part I 



. 









. 











> 






























. . 



■ 



SECTION IV. 



UNITY OF PLAN IN OTHERWISE HIGHLY DIVERSIFIED TYPES. 



Nothing is more striking throughout the animal and vegetable kingdoms than the 



ity of plan in the structure of the most diversified typ 



From pole to pole 



every longitude, mammalia, birds, reptiles, and fishes, exhibit one and the same 




of 



involving abstract conceptions of 



highest order, far transcending the 



broadest generalizations of man, for it is only after the most laborious investig 



man has arrived at an imperfect understanding of this plan 



Other 




qually 



wonderful, may be traced in Articulata 



Mollusks 



Kadiata, 2 and in the various 



typ 



of 




3 



nite diversity in 
trace of intellig 



and yet this logical connection, these beautiful harmonies, this infi 
unity are r< 



presented by some as the result of forces exhibiting 



power of thinking 



faculty of combination, no knowledg 



of time and 



space 



If there is any thing which 




in nature, it is precisely the circumstance that he 

without which, in their most exalted excellence and perfect 



places man above all other beings 

those noble attributes 
on. not one of these 



1 With reference to this point, consult: Oken, 
(Lor.,) Ueber die Bedeutung der Schadel-Knochen, 



und die Verwandtschaftsverhaltnisse der wirbellosen 
Thiere, Braunschweig, 1848, 8vo. — Agassiz, (L.,) 



Frankfort, 1807, 4to. (pamphlet.) — Spix, (J. B.) Twelve Lectures on Comparative Embryology, Bos- 



Cephalogenesis, sive capitis ossei structura, formatio 
et significatio, Monachii, 1815, fol. — Geoffroy St. 
Hilaire, (Et.,) Philosophie anatomique, Paris, 
1818-1823, 2 vols. 8vo., and several papers in the 



ton, 1849, 8vo.— On Animal Morphology, Proc. Amer. 
Assoc, for the Adv. of Science, Boston, 1850, 8vo., p. 
411. I would call particular attention to this paper, 
which has immediate reference to the subject of this 



Annal. des sc. nat., Annal. and Mem. du Museum, chapter. — Carus, (V.,) System der thierischen Mor- 



etc. 



Carus, (C. G.,) Von den Ur-Theilen des phologie, Leipzig, 1853, 1 vol. 8vo. 



Knochen- und Schalengerustes, Leipzig, 1828, fol. 



3 Gothe, (J. W.,) Zur Naturwissenhaft Uber- 



notes par Ch. Fr. Martins, Paris, 1837, 8vo. ; atlas 

DeCandolle, (A. P.,) Organographie 



Owen, (R.) On the Archetype and Homologies of haupt, besonders zur Morphologie, Stuttgardt, 1817- 
the Vertebrate Skeleton, London, 1848, 8vo. 24, 2 vols. 8vo. ; French, Oeuvres d'histoire natu- 

. 2 Oken, (Lob.,) Lehrbuch der Naturphilosophie, relle, comprenant divers memoires d'Anatomie com- 
Jena, 1809-11, 3 vols. 8vo. ; Engl. Elements of paree, de Botanique et de Geologie, traduits et an- 
Physio-philosophy, Ray Society, London, 1847, 8vo. 
Cuviek, (Gr.,) Sur un nouveau rapprochement a 
etablir entre les classes qui composent le Regne Ani- 
mal, Annales du Museum, vol. xix., 1812. 
gny, (J. C.,) Memoires sur les animaux sans verte- 
bres, Paris, 1816, 8vo. — Baer, (C. E. v.,) Ueber 
Entwickelungsgeschichte der Thiere, Konigsberg, 
1828, 4to.— Leukardt, (R.,) Ueber die Morphologie 



in fol. 

vegetale, Paris, 1827, 2 vols. 8vo. — Braun, (Al.,) 
Savi- Vergleichende Untersuchung tiber die Ordnung der 

Schuppen an den Tannenzapfen, als Einleitung zur 
Untersuchung der Blattstellung iiberhaupt, Act. Nov. 
Ac. Nat. Curios., vol. xv., 1829. — Das Individuum 

■ 

cW Pflnnzft. Akad. d. Wiss., Berlin, 1853, 4to. 






■ 











% "^ 







\ 




Chap. I. 



HOMOLOGIES IN DISCONNECTED ANIMALS. 



19 



general traits of relationship so characteristic of the great types of the animal and 
vegetable kingdoms, can be understood, or even perceived. How, then, could these 



relations have been devised without similar powers ? If all these relations are almost 
beyond the reach of the mental powers of man, and if man himself is part and 

t 

parcel of the whole system, how could this system have been called into existence 



if there does 



One Supreme Intelli 



the Author of all thing 












( 






a 

1 Aristoteles, Historia Animalium, Lib. I., Chap. Sect. 4, notes 1 and 2, and the many other works, 
1, Sect. 4. o yaQ b> OQndi tzteqov, tovro . tv i%6vi pamphlets, and papers, quoted by them, which are too 
tori Xmlg. — Consult also the authors referred to in numerous to be mentioned here. 



/ 






SECTION V. 



CORRESPONDENCE IN THE DETAILS OF STRUCTURE IN ANIMALS OTHERWISE ENTIRELY 

DISCONNECTED. 






During the first decade of this century, naturalists began to study relations amon 



5 



* 

animals which had escaped almost entirely the i 
Aristotle knew already that the scales of fishes 
it is 



of earlier observers 



Though 



ipond to the feathers of birds, 1 

correspondence which 



but recently that anatomists have discovered the close corre 

between all the parts of all animals belonging to the same type, however dif- 



- 

ferent they may appear at first sight 



Not only is the wing of the bird identical 



its structure with the arm of man, or the fore leg of a quadruped, it agrees quite as 
closely with the fin of the whale, or the pectoral fin of the fish, and all these 



together correspond in the same 



manner with their hind extremities 



Quite 



strik 



ing a coincidence is observed between 



the solid skull-box, the immovable bones 



of the face and the lower jaw of man and the other mammalia, and the struc 
the bony frame of the head of birds, turtles, lizards, snakes, frogs, and fishes 



of 



B 



this 



ipond 



is 



not limited to the skeleton ; every other system of 



K 



exhibits in these animals the same relations, the same identity in plan and structure, 
whatever be the differences in the form of the parts, in their number, and even in 
their functions. Such an agreement in the structure of animals is called their 



homology, and is more or less close in proporti 



as the animals in which it 



is 



traced are more 



ly related 



The 



same 



greement exists between the different systems and their parts in Art 



ulata 



Mollusks, and in Kadiata, only that their 



built up upon 



the homolo 



g 



have 



tively different plans, though in these three types 

traced to the same extent as among Vertebrata. There is therefore still a wide 



re spec- 
yet been 










u 









■ 
















n:s 



I.X. 










20 



ESSAY ON CLASSIFICATION. 



Part I. 





























































field open for investigations 



in this most attractive branch of Zoology. So much 



however, is already plain from what has been done in this department of 



identity of structure among animals does 



extend 



of the animal kingdom; that 



the contrary, every g 



tyP 



all the four branches 
) is constructed upon 



a distinct 




so peculiar, indeed, that homolog 



type to the other, but are strictly limited within each of them 

resemblance which may be traced between representatives 



cannot be extended from one 

The more remote 



of different 



types, is 



founded upon analogy, 1 and not upon affinity. While, for instance, the head of 
fishes exhibits the most striking homology with that of reptiles, birds, and mammalia, 
as a whole, as well as in all its parts, that of Articulata is only analogous to it and 
to its part. What is commonly called head in 






Insects is not a head like that of 



Vertebrata: it has not a distinct 



cavity for the brain, separated from that which 
communicates below the neck with the chest and abdomen; its solid envelope does 
not consist of parts of an internal skeleton, surrounded by flesh, but is formed of 
external rings, like those of the body, soldered 
which includes the cephalic ganglion, as well as 



o 



ether : it contains but 



tj: 



the 



'g 



of the mouth, and all the 



muscles of the head 



The same may be said of the chest, the legs and wings, the 



abdomen, and all the parts they contain. 



The 



phalic ganglion 



homolog 



to 



b 



are 



the 



'g 



of senses homolog 



to those of Vertebrata, even 



though they perform 



same functions. The alimentary canal is formed in a very 



different way in the embryos of the two typ 



are also their respiratory org 



and it is as unnatural to identify them, as it would be still to consider g 
lungs as homologous among Vertebrata now embryology has taught us 



that 



3 and 
differ- 



ent stages of growth these two kinds of respiratory organs exist in all Vertebrata 



very different org 



connections 



from the other 



What is true of the branch of Articulata when compared to that of Vertebrata, 

equally true of the Mollusks and Eadiata when compared with one another or 

ith the two other types, as might easily be shown by a fuller illustration of the 



pondence of their structure, within these limits 



This 



quality 



the fun 



damental character of the structure of the four branches of the animal kingdom 



p oints to the 



.ty of a radical reform in the nomenclature of comparativ 



tomy 



2 



Some naturalists, however, have already extended such comparisons 



pecting the structure of animals beyond the limits pointed 



by nature, when 



they have attempted to show that all structures may be reduced to one norm 



and 



See Swainson, (W.,) On the Geography and 



mologies of Radiated Animals, with Reference to 



Classification of Animals, London, 1835, 12mo., p. the Systematic Position of the Hydroid Polypi, 



129, where this point is ably discussed. 



Proc. of the Amer. Assoc, for the Adv. of Science 



2 See Agassiz, (L.,) On the Structure and Ho- for 1849, Boston, 1850, 1 vol. 8vo. p. 389. 



























i 






Chap. I. 



DEGREES AND KINDS OF RELATIONSHIP 



21 



when they have maintained, for ins- 
must have its counterpart in every 



that every bone exis 
species of that typ 



g in any Vertebrate 
To assume such a 



uniformity amon 



animals, would amount to denying to the Creator even as much 



freedom 
If if 



b 



xpressing his thoughts as man enjoys. 

true as pointed out above, that all animals are constructed upon four 



different plans of structure, in such a manner 



all 



different kinds of animals 



are 



nly differ 



^pressions of these fundamental formulas, we may well compare 



the whole animal kingdom to a 



work 



g 



four 



g 



ideas, between which 



there is no other connecting link than the unity exhibited in the eggs in which their 



most diversified manifestations are first embodied 



an 



mbry 



form 



underg 



a series of transformations, and appear in the end in that wonderful variety of inde- 
pendent living beings which inhabit our globe, or have inhabited it from the earliest 
period of the existence 



of life upon its surface 



The most surprising feature of 



the animal kingdom seems, however 



neither 



diversity 



m 



the various deg 



of 



com 



of 



to me to 
its struc- 



ture, nor in the close affinity of some of its representati 



while others are so 



different, nor in 
rounding world, but in the ci 
such unequal gifts should n 
connected in all its parts. 



the manifold relations of all of them to one another and the sur- 



that beings endowed with 



different and 



evertheless constitute an harmonious whole, intelligibly 



SECTION VI. 













VARIOUS DEGREES AND DIFFERENT KINDS OF RELATIONSHIP AMONG ANIMALS 



The decrees of relationship existing between different animals are most diversified 



They 




are not 



resemblance 



akin as repr 



of the same species, bearing as such the 



another- different species may also be related as members 



of the same 



g 



the 



presentatives of different g 



may belong to the same 



family, and the same order may 



contain different families, the same class different 



orders, and the same typ 



several classes. 



The existence of differ 



de 



6 



of 



affinity between animals and plants which have not the remotest genealogical connec- 

in the most distant parts of the world, which have existed in periods 



which live 



Ion 




g 



by in the history of our earth, is a fact beyond dispute, at least, within 



certain limits, no 



g 



troverted by well informed observers 



Up 



what can 



this be founded ? Is it that the retentive capacity of the memory of the physical 
forces at work upon this globe is such, that after bringing forth a type according to 

in the infancy of this earth, that pattern was adhered to under conditions, 



pattern 






















■ 






v.' 



^ 







%b 







?«v 



^ 









































































22 



ESSAY ON CLASSIFICATION 



Part I. 



no 



matter how diversified, to reproduce, at another period, something similar, and so 



through all ages, until at the period of the establishment of the present 



of 



things, all the infinitude of new animals and new plants which now crowd 



should be cast in these four moulds 



such a manner 



exhibit, notwithstanding 



their complicated relations to the surrounding world, all those more deeply seated 
general relations, which establish among them the different degrees of affinity we 



may trace so readily in all the representatives of the same type ? 



Does all this 



really look more like the working of blind forces than like the creation of a reflec- 



^ 



tive mind establishing deliberately all the categories of existence we recognize in 
nature, and combining them in that wonderful harmony which unites all things into 
such a perfect system, that even to read it, as it is established, or even with all the 
imperfections of a translation, should be considered as the highest achievement of 
the maturest genius ? 



Nothing seems to me to 



prove more directly and more fully the action of a 



reflective mind, to indicate more plainly a deliberate consideration of the subj 



than 



different 



categories upon which species, genera, families, orders, classes, and 
branches are founded in nature, and manifested in material reality in a succession of 
individuals, the life of which is limited in its duration to comparatively very short 
periods. The great wonder in these relations consists in the fugitive character of the 
bearers of this complicated harmony. For while species persist during long periods, 
the individuals which represent them are ever changing, one set dying after the 
other, in quick succession. Genera, it is true, may extend over longer periods; fami- 
lies, orders, and classes may even have existed during all periods during which 
animals have existed at all; but whatever may have been the duration of their 
existence, at all times these different divisions have stood in the same relation to 
one another and to their respective branches, and have always been represented 
upon our globe in the same manner, by a succession of ever renewed and short-lived 
individuals. 

As, however, the second chapter of this work is entirely devoted to the consider- 
ation of the different kinds and the different degrees of affinity existing among 
animals, I will not enter here into any details upon this subject, but simply recall 

■ 

the fact that, in the course of time, investigators have agreed more and more with 
one another in their estimates of these relations, and built up systems more 
more conformable to one another. This result, which is fully exemplified by the 

* 

history of our science/ is in itself sufficient to show that there is a system in nature 




and 



1 Spix, (J.,) Geschichte und Beurtheilung aller naturelles, Paris, 1826, 4 vols. 8vo. 



Histoire des 



Systeme in der Zoologie, Nurnberg, 1811, 1 vol. 8vo. sciences naturelles, etc., Paris, 1841, 5 vols. 8vo. 



r 



Cuvier, (G.,) Histoire des progres des sciences 



DeBlainville, (H.,) Histoire des sciences de 











Chap. I. 



EARLIEST TYPES OF ANIMALS. 



23 









to which the different systems of authors are successive approximations, more and 

more closely aoreeino; with it, in proportion as the human mind has understood 
nature better. This growing coincidence between our systems and that of nature 
shows further the identity of the operations of the human and the Divine intellect; 



especially when it is 



remembered to what an extraordinary degree many a priori 



conceptions, relating to nature, have in the end proved to agree with the reality, 
in spite of every objection at first offered by empiric observers. 









SECTION VII. 









SIMULTANEOUS EXISTENCE IN THE EARLIEST GEOLOGICAL PERIODS, OF ALL THE GREAT 

TYPES OF ANIMALS. 



It was formerly believed by geologists and paleontologists that the lowest animals 

upon this globe, and that they were followed by higher 



first made 
and highe 



*yp 



appearance 
s, until man 



senting at all the present state of our knowledg 



crowned the series. Every geological museum, repre 

may now furnish the evidence 



that this is not the case. 



belon 



gin 




to all the four g 



On the contrary, representatives of numerous families 
branches of the animal kingdom, are well known to 

Nevertheless, I well 



have existed simultaneously in the oldest geological formations 



remember when I used to 
Corals 



1 



hear the great geologists of 



the time assert, that the 



were 



first inhabitants of our globe, that Mollusks and Articulate followed 



in 



order, and that Vertebrates did not appear until long after these 



What 



an 



extraordinary change the last thirty years have brought about in our knowledge, and 
the doctrines generally adopted respecting the existence of animals and plants m past 

However much naturalists may still differ in their views regarding the origin, 
the gradation, and the affinities of animals, they now all know that neither Radiate, 
nor Mollusks. nor Articulate, have any priority one over the other, as to the time 



ages! 






i 






c 









t 



It f 







I 

■ 

iw~ • x. . . i A ^ a pn n 'o 1847 3 vols. serling, (Count Alex, von,) The Geology of 

I organisation et de leurs progres, raris^ lo^/, o vui». ? \ ?/ &j 

8vo. — PoiirHFT (F A. } Histoire des sciences na- Russia in Europe, and the Ural Mountains, London, 



turelles au moyen age 



Paris, 1853, 1 vol. 8vo. 



Russia in Europe, and the Ural Mountains, London, 

■ 

1845, 2 vols. 4to. — Hall, (James,) Palaeontology 
of New York, Albany, 1847-52, 2 vols. 4to. — Bar- 



Compare, also, Chap. II., below. 

1 Murchison (R. I.,) The Silurian System, Lon- rande, (J.,) Systeme silurien du centre de la Bo- 



don, 1839, 1 vol. 4to. — Mlrchison, (Sir R. L,) 



heme, Prague and Paris, 1852, 2 vols. 4to.— Sedg- 



Siluria. The History of the Oldest Known Rocks wick, (A.,) and McKot, (Fr.,) British Palaeozoic 



containing Fossils, London, 1854, 1 vol. 8vo. 
chison, (R. I.,) de Verneuil, (Ed.,) and Kai- 



Mur- Rocks and Fossils, London, 1851, 4to. 2 fasc; not 



yet complete. 









r»» 






















* ■ x ^l. 











^ 



24 



ESSAY ON CLASSIFICATION. 



Part I. 
































































of their first appear 



upon earth 



and though some still maintain that Vertebr 



originated somewhat later, it is universally conceded that they were already in exist- 
ence toward the end of the first great epoch in the history of our globe. I think 

to show upon physiological grounds that their presence upon 



would not be difficult 



earth dates from as early a period as any of the three other g 



typ 



of the 



animal kingdom, since fishes exist wherever Radiata, Mollusks, and Articulata are 



ether, and the plan of structure of these four g 



found 

system intimately connected in its very essence. 

years, 
the O] 



*yp 



constitutes a 



Moreover, for the last twenty 



every 



extensive investigation 



g 



among the oldest fossiliferous rocks has carried 

of Yertebrata step by step further back, so that whatever may be the 
final solution of this vexed question, so much is already established by innumerable 
facts, that the idea of a gradual succession of Radiata, Mollusks, Articulata, and Ver- 
tebrata, is for ever out of the question. It is proved beyond doubt, that Radiata, 
Mollusca, and Articulata are everywhere found together in the oldest geological for- 

Vertebrata are associated with them, to continue 

This shows that even in 




mations, and that very 




gether through all geological ages to the present time 



those 




days of the existence 



of our globe, when 



surface did 



yet present 




those diversified features which it has exhibited in later periods, and which it exhibits 



in 



still g 



upon 



wer 



riety now, animals belonging to all the great types now represented 

i 

simultaneously called into existence. It shows, further, that unless 

tins, and impressed 




the physical elements then at work could have devised such 

them upon the material world as the pattern upon which Nature was to build for 



exist among all animals, of all 



ever afterwards, no such general relations as 

logical periods, as well as among those now living, could ever have existed 



g 



This is not all 



every class among 



Radiata, Mollusks, and Articulata, is known 



have been represented in those earliest days, with the 



ption of the Acaleph 



and Insects only. It is, therefore 




the plan of the four great types which 



ha\" 



b 



adopted' then, the manner in which these plans were to be executed 



the systems of form under which these 



were 



be clothed, even the ulti 



mate details of 



which in different g 



bear definite relations to those of 



other 



g 



4 

the mode of differentiation of species, and the nature of their rela 



tions to the surrounding media, must likewise have been 
of the classes is as well defined as that of the four g 



determined, as the character 
eat branches of the animal 



kingdom, or that of the families, the genera, and the species. Again, the first rep- 
resentatives of each class stand in definite relations to their successors in later 



1 Acalephs have been found in the Jurassic Lime- softness of their body. Insects are known as early 

as the Carboniferous Formation, and may have ex- 



stone of Solenhofen ; their absence in other forma- 
tions may be owing simply to the extraordinary 



isted before. 

















: ' 



1 ■ 



Chap. I 



EARLIEST TYPES OF ANIMALS. 



25 



periods, and as their order of appariti 



iponds to the various degrees of com- 



plication 



their structure, and forms natural series closely linked together, this 



b 



6 



to him as its 



natural gradation must have been contemplated from the very beginning. Ther 
can be the less doubt upon this point, as man, who comes last, closes in his ow 
cycle a series, the gradation of which points from the very 
last term. I think it can be shown by anatomical evidence that man is not only 
the last and highest among the living beings, for the present period, but that he is 
the last term of a series beyond which there is no material progress possible upon 



the 




upon 



which the whole animal kingdom is constructed, and that the only 



improvement we may look to upon earth, for the future, must 
ment of man's intellectual and moral faculties. 1 



the develop 



The question has been raised of late how far the oldest fossils known may truly 



be the remains of the first inhabitants of our globe 
fossiliferous rocks have been intensely altered by plut 



N 



doubt 



sxtensive tracts of 
and their organic 



contents so entirely destroyed, and the rocks themselves so deeply metamorphosed 



that they resemble now more closely 
Such changes have taken place ag 



ptive rocks even than stratified dep 



and ag 



up 



comparatively 



periods 



and upon a very larg 



scale. 



Yet there are entire continents, North America, for 



instance, in which the palae 



rocks have underg 



little, if any, alteration, and 



here the remains of the earliest representatives of the animal and vegetable kin 




doms 



well preserved 



later formations. In such dep 



the evidence 



satisfactory that a 



tj 



of animals belonging to different classes of the great 



branches of the animal kingdom 



existed simultaneously from the beginning 



so 



the assumption of a 



successive introduction of these types upon earth 



flatly 



contradicted by well established and well known facts 



Moreover, the remains found 



in the oldest deposits, are 
Sweden, in Bohemia, and 



ywh 



ly allied to one another. In Eussia 



various other parts of the world, where these oldest 



format 



have b 



ltered upon a mor 



as in 



North America, where they have underg 



or less extensive scale, as well 

little or no change, they present the 



same general chai 



that close 



iponden 



their structure and in the 



combination 
neous faunae 



of their families, which shows them to have belonged to contemp 



It 



of the 



ould therefore, seem that even where metamorphic rocks prevail, 
.rliest inhabitants of this globe have not been entirely obliterated 


















\ 






1 Agassiz, (L.,) An Introduction to the Study Number of Animals in Geological Times, Amer. 
of Natural History, New York, 1847, 8vo. p. 57. Journ. of Science and Arts, 2d ser., vol. 17, 1854, 



2 Agassiz, (L.,) The Primitive Diversity and 



4 



p. 309. 



\ 











L 

-• ■ : 



.^%*-*JK 



I < 














■ 



-_.-- 












' 












26 



ESSAY ON CLASSIFICATION. 



Part I. 



SECTION VIII. 



THE GRADATION OF STRUCTURE AMONG ANIMALS. 







There is not only variety among animals and plants; they diner also as to their 

* 

standing, their rank, their superiority or inferiority when compared to one another. 
But this rank is difficult to determine; for while, in some respects, all animals are 



equally perfect, as they perform completely the part assigned 



them in the general 



economy of nature, 1 in other respects there are such striking differences between 
them, that their very agreement in certain features points at their superiority or 

inferiority in regard to others. 



This being the case, the question first arises, D 



all animals form 



unbroken 



from the lowest to the highest 



Before the animal kingdom had been studied 



i t 



so closely as it has been of late, many able writers 



ally believed that all animals 



formed but one simple continuous series, the gradation of which Bonnet has b 



particularly industrious in trying to ascertain. 2 



At a later period, Lamarck 



has 



endeavored to show further, that in the complicat 



of their structure, all the 




successive deg 



gement classes constitute one grad 



classes of the animal kingdom represent or 

thoroughly convinced that in his systematic ar 

ual series, that he actually calls the classes "degrees of organization. 

has in the main followed in the steps of Lamarck, though he does 



and he is so 



4 



DeBlainville 



admit quite 



so simple a series, 



for he considers the Mollusks and Articulates as two diverging 



branches ascending from the Eadiata 



But since 



known how the g 



circumscribed, 5 notwithstanding a few doubtful points; since 



tiverge again and unite in the Vertebrata. 
branches of the animal kingdom may be 

it is now known how 

















1 Ehrenberg, (C. G.,) Das Naturreich des Men- 

■ 

schen, oder das Reich der willensfreien beseelten Na- 
turkorper, in 29 Classen iibersichtlich geordnet, Ber- 
lin, 1835, folio, (1 sheet). 

2 Bonnet, (Ch.,) Considerations sur les corps 

■ 

organises, Amsterdam, 1762, 2 vols. 8vo. — Contem- 
plations de la Nature, Amsterdam, 1764-65, 2 vols. 



4 Blainville, (H. D. de,) De l'Organisation des 
Animaux, Paris, 1822, 1 vol. 8vo. 

■* Blumenbach, (J. Fr.,) Handbuch der verglei- 
chenden Anatomie, Gottingen, 1824, 1 vol. 8vo. ; 
Engl, by W. Lawrence, London, 1827, 1 vol. 8vo. 

Cuvier, (G.,) Lecons d' Anatomie compared, rec. 



et publ. par 



MM. Dumeril et Duvernoy, Paris, 



8vo. 



Palihgenesie philosophique, Geneve, 1769, 2 1800-1805, 5 vols. 8vo. ; 



MM 



vols. 8vo. 

3 Lamarck, (J. B. de,) Philosophic zoologique, 

Paris, 1809, 2 vols. 8vo. 



F. G. Cuvier et Laurillard, Paris, 183-6-89, 10 vols. 



8vo. 



Cuvier, (G.,) 



Le Regne 



animal distribue 



d'apres son organisation, Paris, 1817, 4 vols. 8vo.5 




I 



















RX^te ^ ■ ■■■& 





Chap. I. 



GRADATION OF STRUCTURE AMONG ANIMALS 



27 



most classes should be characterized, and what is their respective standing; since 
every day brings dissenting views, respecting the details of classification, nearer 
together, the supposition that all animals constitute one continuous gradated series, 
can be shown to be contrary to nature. Yet the greatest difficulty in this inquiry, 
is to weigh rightly the respective standing of the four great branches of the whole 
animal kingdom; for, however plain the inferiority of the Radiata may seem, when 
compared with the bulk of the Mollusks or Articulata, or still more evident when 
contrasted with the Vertebrata, it must not be forgotten, that the structure of most 
Echinoderms is far more complicated than that of any Bryozoon or Ascidian of the 

that of any Helminth, of the type of Articulata, and, perhaps, 

These facts are so well 



type of Mollusks, or 

even superior to that of the Amphioxus among Vertebrata. 



ascertained, that an absolute superiority or inferiority of one type over the other 
must be unconditionally denied. As to a relative superiority or inferiority however, 
determined by the bulk of evidence, though it must be conceded that the Vertebrata 
rank above the three other types, the question of the relative standing of Mollusks 
and Articulata seems rather to rest upon a difference in the tendency of their whole 
organization, than upon a real gradation in their structure ; concentration being the 
prominent trait of the structure of Mollusks, while the expression ' outward display ' 
would more naturally indicate that of Articulata, and so it might seem as if Mollusks 



and Articulata were 



standing on 



nearly a 



level with one another, and as much 




iii 



I 



i 




2de edit. 1829-30, 5 vols. 8vo.; 3e edit, illustree 
1836 et suiv; Engl. Trans, by Griffith, London, 
1824, 9 vols. 8vo.— Meckel, (J. F.,) System der 
vergleichenden Anatomie, Halle, 1821-31, 6 vols. 
8vo. ; French Transl., Paris, 1829-38, 10 vols. 8vo. 

Treviranus, (G. R.,) Biologie, oder Philosophic 
der lebenden Natur, Gottingen, 1802-16, 6 vols. 8vo. 

Die Erscheinunjren und Gesetze des organischen 




Lebens, Bremen, 1831-37, 5 vols. 8vo. 
Chiaje, Istituzioni d'Anatomia e Fisiologia compa- 
rata, Napoli, 1832, 8vo. — Carits, (C. G.,) Lehrbuch 
der vergleichenden Anatomie, Leipzic, 1834,. 2 vols., 
4to., fig. 2d edit. ; Grundsatze der vergleichenden Ana- 
tomie, Dresden, 1828, 8vo.; Engl, by R. «T. Gore 



Leipzic, 1843-44, 1 vol. 8vo., 2d vol. by Frey and 
Leuckardt ; Icones anatomical, Leipzig, 1841, fol. 
Grant, (R. E.) Outlines of Comparative Anat- 
omy, London, 1835, 1 vol. fol. — Jones, (Rymer,) 
A General Outline of the Animal Kingdom, London, 

1838-39, 1 vol. 8vo. fig. ; 2d edit. 1854. — Todd, (R. 

B.,) Cyclopedia of Anatomy and Physiology, London, 

1835-52, 4 vol. 8vo. fig. — Agassiz, (L.,) and Gould, 



Delle (A. A.,) Principles of Zoology, Boston, 1 vol. 8vo., 

2d edit. 1851. — Owen, (R.,) Lectures on the Inver- 
tebrate Animals, London, 1843, 1 vol. fig. ; 2d edit. 
1855. — Lectures on the Comparative Anatomy of 



the Vertebrate Animals, Fishes, London, 1846, 1 vol. 
8vo.. fig. — Siebqld, (C. Th. v.,) und Stannius, 



Bath, 1827,2 vols. 8vo. Atlas. - Carits, (C. G.,) and (Herm.,) Lehrbuch der vergleichenden Anatomie, 

Berlin, 1845-46, 2 vol. 8vo. ; 2d edit. 1855 ; Engl. 



W 



Wagner 



W 



Berg- 



\ 



den Anatomie, Leipzic, 1826-40, fol. 

(R.,) Lehrbuch der vergleichenden Anatomie, Leipzic, mann, (C.,) und Leuckardt, (R.,) Vergleichende 

1834-35, 2 vol. 8vo. ; Engl, by A. Tulk, London, Anatomie und Physiologie, Stuttgardt, 1852, 1 vol. 

1844, 1 vol. 8vo.; 2d edit. Lehrbuch der Zootomie, 8vo. fig. 


















i 



. ■ 



'■'•'•:•■ 



■ - ; - 
* * ■ • • . 



—WT^^^ 






*■*■■ ** 



■ 













: i>v 




S 







'X. 
















28 



ESSAY ON CLASSIFICATION. 



Part I 
































above Kadiata, as both stand below Vertebrate, but constructed upon plans expressing 

appreciate more precisely these most general relations 



different tendencies 



To 



among the great types of the animal kingdom, will require deeper investig 

tin of structure than have been made thus far. 1 



the character of their 




Let, how' 



the respective standing of these great divisions be what it may 



let them differ 



nly 



in 



dency, or in plan of structure, or in the height to which they rise, 



admitting their base to be on one level or nearly so, so much is certain, that 



each type there are representatives exhibitin 



a 



ghly complicated structure and 



others which appear very 



pie 



Now, the very fact that such 



ernes may 



b 



traced, within the natural boundaries of each type, shows that in whatever manner 
these great types are supposed to follow one another in a single series, the highest 

on to the lowest representative of 

5 It 



representative of the preceding type must j 



the following, thus bringing necessarily together the most heterogeneous forms 



must be further evident, that in proportion as the internal 



gement of each g 



type will be more perfected, the greater is likely to appear the difference 



the two 



ends of the 



which 



ultimately to be brought into 



with those of 



other series, in any attempt to establish a single series for all animals 



I doubt whether there 



is a naturalist now living who could object to an arrange- 
ment in which, to determine the respective standing of Radiate, Polyps would be 



placed lowest, Acalephs next, and Echinoderms highest 



a similar 



gement of 



Mollusks would bring Acephala lowest, Gasteropoda next, and Cephalopoda highest; 
Articulata would appear in the following order: Worms, Crustacea, and Insects, and 
Vertebrate, with the Fishes lowest, next Reptiles and Birds, and Mammalia highest. 
I have here purposely avoided every allusion to controverted points. Now if Mol- 

Acephala should join on to the 



lusks were to follow Radiate in a simple series. 
Echinoderms; if Articulata, Worms would be the 
have either Cephalopods or Insects, as the highest term of a series beg 



connecting link 



We should then 



with 



Radiata, followed by Mollusks or by Articulates 



In the first case, Cephalopods 



would be followed by Worms ; in the second, Insects by Acephala. Again, the con- 
nection with Vertebrate would be made either by Cephalopods, if Articulata were 
considered as lower than Mollusks, or by Insects, if Mollusks were placed below 

Articulata. 

true affinities of animals is improvin 



Who does not see, therefore, that in proportion as our knowledge of the 



we accumulate more and more convincing 



evidence against the idea that the animal kingdom constitutes one simple series? 



1 I regret to be unable to refer here to the con- 
tents of a course of lectures which I delivered upon 
this subject, in the Smithsonian Institution, in 1852. 
Compare, meanwhile, my paper, On the Differences 



between Progressive, Embryonic, and Prophetic 
Types, Proc. Am. Assoc, for 1849, p. 432. 

2 Agassiz, (L.,) Animal Morphology, Proc. Am. 
Assoc, for 1849, p. 415. 
















** Ul 









Chap. I. 



GRADATION OF STRUCTURE AMONG ANIMALS. 



29 



The next question would then he 
any number of graduated 



Does the animal kingdom constitute several, 



In attempting 



the value of the less 



comprehensive groups 
gradually less and less 



when compared to one another, the difficulties seem to b 



It is already possible 



•k out with tolerable precision 



the relative standing between the classes, though even here we do not yet perceive 



in all the typ 



the same relations 



Among Verteb 



doubt, that the Fishes are 

Mammalia stand highest 



there can be little if any 
lower than Birds, and that 



lower than the Reptiles, these 

it seems equally evident, that in the main, Insects and 



Crustacea are superior 



to Worms Cephalopods to Gasteropods and Acephala and 



Echinoderms to Acalephs and Polyp 



But there are genuine Insects, the superiority 



of which 



many 



Crustacea, would be difficult to prove 



there are Worms which 



in every respect appear superior 



to certain Crustacea; the structure of the highest 



Acephala seems more perfect than that of some Gasteropods, and that of the Haley 




noid Polyps more 



perfect than that of many Hydroids 



Classes do, therefore, not 

A 



seem 



be 



limited in the 






of their characters, as to justify in every type a 



. 



complete serial arrangement among them 
hardly be doubted that the gradation 



But when we come to the orders 



can 



of 



these natural divisions among themselves ir 

of this kind of groups. As a special para 

the consideration of the character of orders in my next chapt 



each class, constitutes the very essence 
graph is devoted to 
I need not dwell longer upon this point 
remark now, that the difficulties geolog 



here 



It will be sufficient for me to 



have met with, in their attempt 



com' 



pare the rank of the different typ 



of animals and plants with the order of their 



succession m 



different geological periods, has chiefly arisen from the circumstance, that 



they have expected to find a serial gradation 



not only among the 



classes of the 



same typ 



where it is 




incomplet 



r ? 



between which such a gradation cannot be traced 



but even among the types themselves 

Had they limited their compari- 



sons to the orders which are 



ny 



founded upon gradation, the result would have 



b 



quite different 



but to do this 



quires more familiarity with Comp 



Anatomy, with Embryology and with Zoology proper 
of those, the studies of which are 



than 



can naturally be expected 
chiefly devoted to the investigation of the struct- 



ure of our globe 

To appreciate fully the 

and to compr 



importance of this question of the gradation of animals, 
ehend the whole extent of the difficulties involved in it, a superficial 



quaintance with the perplexi 



question 



past geological ages, is by no means sufficient ; 
attempts which have been made to establish a 
with all the crudities which have been published upon this 



of the order of succession of animals in 

a complete familiarity with the many 

the two. and 



pondence between 



ubject, might dispel 



, 



1 



See Chap. II. 



-. .^. 












tl 
























9 



i 






























■ • : • ■ ■ ■ 



' i .■ 



< 



•:•..• :.• ■ 



:, '.■■■■<■■ •■ 



■'•.'■• •' 
















■ .i 











< 



^ 









^* 










» 






























30 



ESSAY ON CLASSIFICATION. 



Part I. 



every hope to arrive at any satisfactory result upon this subject, did it not appear 



now, that the 



inquiry 



be circumscribed within different limit 



be conducted 



upon its true ground. The results to which I have already arrived, since I have 
perceived the mistake under which investigators have been laboring thus far, in 
this respect, satisfy me that the point of view under which I have presented the 
subject here is the true one, and that in the end, the characteristic gradation 



exhibited by the orders of each class, will present the most striking c 
with the character of the succession of the same groups in past ag 



3spondence 
and afford 



another startling proof of the admirable order and gradation which have b 



estab 



lished from the very beg 



and maintained through all times in the degrees of 



complication of the structure of animals. 











SECTION IX. 



























EANGE OF GEOGEAPHICAL DISTRIBUTION OF ANIMALS 



the 



The surface of the earth being partly formed by water and partly by land, and 
organization of all living beings standing in close relation to the one or the other 



of these mediums, it is in the nature of things, that 



o 



le species, either of ani- 



mals or plants, should be uniformly distributed over the whole globe, 
are some types of the animal, as well as of the vegetable kingdom, which 



Yet there 
•e equably 



distributed over the whole surface of the land, and others which are as widely scat- 
tered in the sea, while others are limited to some continent or some ocean, to some 
particular province, to some lake, nay, to some very limited spot of the earth's 
surface. 1 

■ 

As far as the primary divisions of animals are concerned, and the nature of the 
medium to which they are adapted does not interfere, representatives of the four 



g 



branches 



of the animal kingdom are everywhere found together 



Radiata 



- 

Mollusks, Articulata, and Vertebrata occur 



& 



ether in every part of the ocean, in 



i 

the Arctics, as well as under the equator, and near the southern pole as far as man 



has penetrated; every bay, every inlet, every shoal is haunted by them 



So univer- 









i 













1 The human race affords an example of the wide Ocean, how fishes may be circumscribed in the sea, 



distribution of a terrestrial type ; the Herring and 
the Mackerel families have an equally wide distri- 
bution in the sea. The 



and that of the Goniodonts of South America in 

I 

the fresh waters. The Chaca of Lake Baikal is 



m 



Mammal 



i of New Hoi- found nowhere else ; this is equally true of the 

_ i 

land show how some families may be limited to one Blindfish (Amblyopsis) of the Mammoth Cave, and 



continent ; the family of Labyrinthici of the Indian 





r- 



> ^ 



e 



**j 



of the Proteus of the caverns of Carinthia. 



9 




: 










*ff 







jM> 






W 















Chap. I. 



GEOGRAPHICAL RANGE 



ANIMALS 



association, 




present 



geological 




a sufficient reason to expect, that fishes will be found in those few 



consider it as 

fossiliferous beds of the Silurian System 



which thus far they have 



yet been 



found. 1 Upon land, we find equally everywhere Yertebrata, Articulata, and Mollusks 



but 



Radiata, this whole branch being 



mited 



waters : but as far 




trial animals extend, we find representativ 



of the other three branches associated 



we find them all four in the 



Classes have already a more limited range of 



distribution. Among Radiate, the Polypi, Acalephs, and Echinoderms are not only 



all 



quatic, they are all marine, with a 

■m/r_«._„U«4 



single 



pti 



the 



g 



Hyd 



which 



inhabits fresh waters 



marine 



Among Mollusks 



the Acephala are all aquatic, but partly 

and partly fluviatile, ~the Gasteropoda partly marine, partly fluviatile and 

marine. Among Articulata, 5 the Worms 

terrestrial, while many are internal 



partly terrestrial, while all Cephalopoda are 
are partly marine, partly fluviatile, and partly 



1 See, above, Sect. 7. 
For the geographical distribution of Radiata, 
consult: Dana, (J. D.,) Zoophytes. United States 
Exploring Expedition, under the command of Ch. 

U. S. N., Philadelphia, 1846, 1 vol. 4to. 
Atlas fol. — Milne-Edwards et Haime, (Jul.,) 

Recherches sur les Polypiers, Ann. Sc. Nat. 3e ser. 



Wilkes 



vol. 9-18, Paris, 1848-52, 8vo. 



ESCHSCHOLTZ, 



(Fr.,) System der Acalephen, Berlin, 1829, 4to. fig. 
Lesson, (R. Pr.,) Histoire naturelle des Zoophy- 
tes, Acalephes, Paris, 1843, 1 vol. 8vo. fig. — Kolli- 
ker, (A.,) Die Schwimmpolypen und Siphonophoren 
von Messina. Leinzic, 1853, 1 vol. fol. fig. — Mul- 



Hayes. — Ferussac, (J. B. L. be,) et Sander- 
Rang, (A.,) Histoire naturelle des Aplysiens, Paris, 
1828, 4to. fig. fol. — Ferussac, (J. B. L. be,) et 
d'Orbigny, (A.,) Monographie des Cephalopodes 
cryptodibranches, Paris, 1834-43, fol. — Martini, 
(F. H. W.,) und Chemnitz, (J. H.) Neues syste- 
matisches Conchylien-Kabinet, Nurnberg, 1769-95, 
1 1 vols. 4to. fig. ; new edit, and continuation by 

* 

Schubert and A. Wagner, completed by H. C. 

Kuster, Nurnberg, 11 vols. 4to. fig. — Kiener, (L. 

Kolli- C.,) Species general et Iconographie des Coquilles 



vivantes, Paris, 1834, et suiv 



? 



8vo. fig. 



Reeve, 



ler, (J.,) und Troschel, (F. H.,) System der 
Asteriden, Braunschweig, 1842, 8vo. fig. — Agassiz, 
(L.,) Catalogue raisonne des families, des genres et 
des especes de la Classe des Echinodermes, Ann. des 
Sc. Nat. 3e ser. vol. 6-8, Paris, 1847, 8vo. 

8 I need hardly say in this connection that the 
so-called fresh-water Polyps, Alcyonella, Plumatella, 
etc., are Bryozoa, and not true Polyps. 

4 T^ ._ xi_ _A.: M 1 ^icfrihntiOTl of Mollusks, 



(Lovell,) Conchologia Iconica ; a Complete Repertory 
of Species of Shells, Pictorial and Descriptive, Lon- 

Pfeiffer, (Tu.<) Mon- 



g- 



don, 1843, and foil., 4to. fi 

oo-raphia Heliceorum viventium, Leipzig, 1847-48, 



8vo. 



Pfeiffer, 



Monog: 



morum viventium, Cassel, 1852, 8vo., and all the 
special works on Conchology. 

5 The mode of distribution of free or parasitic 
Worms, in different parts of the world and in differ- 
ent animals, may be ascertained from: Grube, (A. 
Eb.,) Die Familien der Anneliden, Wiegman's Ar- 



consult: Lamarck, (J. B. be,) Histoire naturelle 

des Animaux sans vertebres, Paris, 1815-22, 7 vols. chiv, 1850. I mention this paper in preference to 



8vo.; 2de edit, augmented de notes par 



MM. 



any other work, as it is the only complete list of An- 



DesHayes and Milne-Ed wards, Paris, 1835-43, nnlata; and though the localities are not given, the 

10 vols. 8vo.- Ferussac, (J. B. L. de,) Histoire references may supply the deficiency. - Kudolphi, 

naturelle des Mollusques terrestres et fluviatiles. (K. A,) Entozoorum sive Vermium intestinalium 

Paris, 1819 et suiv, 4to. fig. fol., continued par Des- Historia naturalis, Amstelodami, 1808-10, 3 vols. 









I 















• 



■■■• ■. 





; . ■•■.• • 




r« n » nnii 






rr" 








































32 



ESSAY ON CLASSIFICATION. 



Part I. 



parasites, livin 



cavities or in the 



'g 



of other animals : the Crustacea 



partly marine and partly fluviatile 
restrial or rather aerial, yet some ; 



few are terrestrial; the Insects are mostly ter- 
marine, others fluviatile, and a large number of 



those, which in their perfect state live in the air, are terrestrial or even aquatic 
during their earlier stages of growth. Among Vertebrata J the Fishes are all aquatic 



but partly 



and partly fluviatile; the Eeptiles 



either aquatic, or amphibious 



and some of the latter 



quatic during the early part of their life 



the Birds are all aerial, but some more terrestrial and others more aquatic 



finally 



the Mammalia 



gh all aerial live partly in the 



par 



in fresh water, but 



mostly upon land. A more special review might show, that this localization in c 
nection with the elements in which animals live, has a direct reference to peculi 



ties of structure of such importan 
mals within the limits of the cl 



that a close consideration of the habitat of ani- 



mig 



most 



lead to a very natural 



classification. 2 But this is true only within the limits of the classes, and even here 











































vols. 8vo., fig. — Muller, (J.,) und Henle, (J.,) 

Systematische Beschreibung der Plagiostomen, Ber- 
welchen Entozoen gefunden worden sind, Wiegman's lin, 1841, fol. fig. For that of Reptiles : Dumeril, 



8vo. fig. — Entozoorum Synopsis, Berolini, 1819, 8vo. 
fig. — Gurlt, (E. F.,) Verzeichniss der Thiere, bei 



Archiv, 1845, contin. by Creplin in the following No. 



M 



> 



(G.,) Erpetologie generate, 



Dujardin, (Fel.,) Histoire naturelle des Hel- ou Histoire naturelle complete des Reptiles, Paris, 



minthes ou Vers intestinaux, Paris, 1844, 1 vol. 8vo 



1834-1855, 9 vols. 8vo. fig. 



TSCHUDI, (J. J.,) 



Diesing, (C. M.,) Historia Vermium, Vindob. 1850, Classification der Batrachier, Neuchatel, 1838, 4to. 



2 vols. 8vo. That of Crustacea from Milne-Ed- 



Mem. Soc. Neuch. 2d. vol. — Fitzinger, (L. J.,) 



wards, Histoire naturelle des Crustaces, Paris, 1834, Systema Reptilium, Vindobonae, 1843, 8vo. For that 

of Birds : Gray, (G. R,,) The Genera of Birds, illus- 



3 vols. 8vo. fig. — Dana, (J. D.,) Crustacea. Uni- 
ted States Exploring Expedition, under the command 



Mitchell 



of Ch. Wilkes, U. S. N., vol. xiv., Philadelphia, 1852, don, 1844-1849, 3 vols. imp. 4to. — Bonaparte, 
2 vols. 4to., atlas, fol. For the geographical distri- (C. L.,) Conspectus generum Avium, 



Lugduni-Bata 



bution of Insects I must refer to the general works vorum, 1850, and seq. 8vo. For that of Mammalia : 
on Entomology, as it would require pages to enu- Wagner, (A.,) Die geographische Verbreitung der 

Sauothiere, Verhandl. der Akad. der Wissensch. 



in Miinchen, Vol. IV. — Pompper, (Herm.,) Die 
Saugthiere, Vogel und Amphibien, nach ihrer geo- 



graphischen Verbreitung 



merate even the standard works relating to the dif- 
ferent orders of this class; but they are mentioned 
in: Percheron, (Ach. R.,) Bibliographie entomo- 
logique, Paris, 1837, 2 vols. 8vo. — Agassiz, (L.,) 
Bibliographia Zoologize et Geologia3 ; a general cata- 
logue of all books, tracts, and memoirs on Zoology 
and Geology, corrected, enlarged, and edited by H. 
E.Strickland, London, 1848-54, 4 vols. 8vo. (Ray the Jardin des Plantes, etc. 

Society). 



tabellarish zusammenge- 



stellt, Leipzig, 1841, 4to. — See, also, the annual 
reports in Wiegman's Archiv, now edited by Tro- 
schell; the Catalogues of the British Museum, of 



For the geographical distribution of Fishes, 



2 Agassiz, (L.,) The Natural Relations between 
Animals and the Elements in which they live. 



consult: Cuvier, (G.,) and Valenciennes, (A.,) Amer. Jour, of Sc. and Arts, 2d ser., vol. 9, 1850, 

■ 



Histoire naturelle des Poissons, Paris, 1828-1849, 22 



8vo., p. 869. 












«■ 




■ 



Chap. I. 




GEOGRAPHICAL RANGE 



ANIMALS. 




famil 



not absolutely, as in some 

related to the elements; there are even natural groups, in which this connection is 

not manifested beyond the limits of the genera, and a few cases in which it is actually 



confined to the species 
every spot 



Yet, in every degree of these 



classes and 



of the globe, it extends simultaneously to the representatives 
even of different branches of the animal and vegetable kingdoms 



we find that upon 

is of different 



circum 



which shows that when called 



such 



these 



ous animals and plants were 

> 

kino-dom. those of their class, 



ipectively adapted with all the peculiarit 



their 



those of their order, those of their genus, and those of 



their species, to the home assigned to them, and therefore, not produced by the 



of the pi 



of the element 



any other physical condition 



To maintain the 



contrary, would really amount to 
beings live together, no matter how g 



in their com 



ing there, must have 

diversity of structures as exists in 

which these animals stand to them, or 



serting that wherever a variety of organized 

•eat their diversity, the physical agents prevail- 

bined action, the power of producing such a 

nimals, notwithstanding the close connection in 



selves in bein 



5 



to work out an intimate relation to them- 
the essential characteristics of which, have no reference to their 



* 

nature. In other words 



one side of their 



, g 



which has an i 



and another which has no 



all these animals and plants, there is 
mmediate reference to the elements in which they live, 
such connection, and yet it is precisely this part of the 



structure of animals and plants, which has no direct beai 



■5 



upon the conditions 



which they are placed in 
character. This proves 



nature which constitutes their essential, their typical 



which animals and plant 



is 



beyond the possibility of an objection, that the elements in 
live (and under this expression I mean to include all that 

cannot in any way be con- 



/ 



commonly called physical agents, physical causes, etc.,) 



sidered 



cause 



of their 



If the naturalists of past centuries have failed to improve their systems of Zoology 



by introducing considerations derived from the habitat ^ of animals 
they have taken this habitat as the foundat 



chiefly because 



of their primary divisions 



but 



reduced 



proper limits, the 



dy of the connection between the structure and 



the natural home of animals cannot fail 



lead to interesting results, among which 



the 



growing 



conviction that these relations are not produced by physical 



■g 



'? 



but determined in the plan ordained from the beginning, will not be the least 

important. 

The unequal limitation of groups of a different value, upon the surface of the 

earth, produces the most diversified combinations possible, when we consider the 
mode' of association of different families of animals and plants in different parts of 

These combinations are so regulated that every natural province has a 
character of its own, as far as its animals and plants are concerned, and such natural 

5 



the world. 




I 




























-• " ■ ■ .. ■ 





' 






*W||HI| IIV 



r ^1 



.1.* 



V 










*s 




















LZ1 









34 



SAY ON 



S 



Part I 












































associations of organized beings extending over a wider or narrower area are called 



Faunae when the animals alone are 



garded 



considered, and Florae when the plants alone are 
far from being yet ascertained satisfactorily 



ywhere 



i 

Their natural limits are 

As the works of Schow and Schmarda may suffice to g 



approxi- 



mate idea of their extent, 1 I would refer to them for further details, and allude here 



only to the 



qual 



of 



these different faunae, and to the necessity of limiting 



them in different ways, according to the point of view under which they are con- 



sidered 



rather show that, as different groups have 



wider 



more limited rang 



o 



& 



their 



the faunae, we must distinguish between zoolog 



cal realms, zoological provinces, zoological counties, zoological fields, as it were ; 



that 



is, between zoological areas 



of unequal value over the widest of which range the 



most extensive types, while in their smaller and smaller divisions, we find more and 

another, sometimes placed side by 



more limited types, sometimes 



lapp 



one 



side, sometimes concentric to one another, but always and 



ywhere impressin 



a 



special character upon some part of a 
that of any other part within its 



wider area, which is thus made 



differ from 



natural limits 



These various combinations of smaller or 



wider areas, equally well denned in 



different types, has g 



rise 



pectin 



to the conflicting views prevailing among naturalists 

ess of our knowledge 



the natural limits of faunae; but with the prog 



these discrep 



cannot fail to disapp 



In some respect, every island of the 



Pacific upon which distinct animals are found, may be 
distinct fauna, yet several groups of these islands have 



considered as exhibiting a 
i common character, which 



them into more comprehensive faunae, the Sandwich Islands for 



com 



pared to the Fej 
isolated lakes is 



or to New Zealand 



What is true of disconnected islands 



of 



qually 



of connected parts of the mainland and of the ocean. 



Since it is well known that many animals are limited to a very narrow 



D 



their geographical distribution, it would be 



highly interesting subject of inquiry 



to ascertain what are 



the narrowest limits within which animals of different typ 



may be circumscribed, as 



this would furnish the first basis for a scientific consid- 
eration of the conditions under which animals may have been created. The time 
is passed when the mere indication of the continent whence an animal had been 



obtained, could satisfy our curiosity 



and the 



who, having an opportunity 



of ascertaining closely the particular circumstances under which the animals they 



describe are placed in 



their natural home, are guilty of a g 



disregard 



of the 






interest of science 
graphical distribut 



when they neglect to relate them 



Our knowledge of the geo- 



of animals would be far more extensive and precise than it 



■ 









1 I would also refer to a sketch I have pub- 



Types of Mankind, Philadelphia, 1854, 4to., accom- 



lished of the Faunse in Nott's and Gliddon's panied with a map and illustrations. 

































P^^^^V^^H 



ll I 







Chap. I 



GEOGRAPHICAL RANGE OF ANIMALS 



35 



■ 









& 



is now, but for this n< 

tion of well-known species is 



species 
Alphor 



every new fact 



g to the geographical distribu 



as 



important to science as the discovery of a new 



Could we 




know the range of 



a single animal as 



& 



,tely 



as 



DeCandolle has lately determined that of many species of plants, we 



might beg 



a new era in Zoology 



It 



greatly to be regretted that in most 



ks, containing the scientific results 



of 



plorat 



of distant 



nly 



species 



described when the mere enumeration of those already known might have 



added invaluable information respecting their geographical distribution 



The careless- 



ness with which some 
in distant regions, without 



naturalists distinguish species merely because they are found 



attempting to secure specimens for comparison 



a 



perpetual 



of erroneous conclusions in 



the 



dy of the geographical distribu 




less detrimental to the prog 



of science than the 



consider as i 



tion of organized bein 

readiness of others to 

each other closely, without paying 

without even pointing out the differences they may perceive between specimens from 



dentical, animals and plants which may resemble 
the least regard to their distinct origin, 



and 



different parts of the world 
very remote parts of the 



The perfect identity of animals and 



plants living in 




lobe has so 



often been ascertained, and it is also so 



well known how closely species may 
relations which characterize species, 
i ustifiable 



be allied and yet differ in all the essential 



that such loose 



g 



are no long 



This close resemblance of animals and plants 



distant parts of the world is the 



most interesting subject of investig 



with reference to the question of the 



ity 



of 



gin of animals, and to that of the influence of physical 



beings in general. It 



appears 



to me 



that 



agents upon organized 
the facts point now distinctly to an 



independent 



origin of individuals 



of the same species 



in remote 



: g 



or of 



closely allied species representing one 



another in distant parts of the world, one 



of the 



had a controlling influence 
for ever. 



guments in favor of the supposition that physical agents may have 



chanoing the character of the organic world, is g 



The narrowest limits within which certain Vertebrata may be circumscribed 



Out an 



gs upon 



r 

ern coast 



Hop< 
Ame 



and 



and remarkable species: the Orang- 

and the Gorilla along the west- 

of Africa, several distinct species of Rhinoceros about the Cape of Good 

South 



exemplified, among Mammalia, by some larg 

the Sunda Islands, the Chimp 



Java and Sumatra, the Pinchaque and the common Tap 



and the eastern Tap 



Sumatra, the East Indian and the African Ele 



phant, the Bactrian Camel and the Dromedary, the Llamas, and the different kinds 
of wild Bulls wild Goats, and wild Sheep, etc. ; among birds by the African Ostrich, 



the two Amer 



(C 



Rheas, the Casovary (Dromicej 



of New Holland, and the Emeu 



p 

galeatus) of the Indian Archipelago, and still more by the different 


























































36 



ESSAY ON CLASSIFICATION. 



Part I. 

























species of doves confined to particular islands 



the Pacific 



among Keptiles 



by the Proteus of the 
phemus Auct.) of our 



cave of Adelsberg in Carinthia, by the Gopher (Testudo Poly- 
Southern States ; among fishes, by the Blind Fish ( Amblyopsis 



spelseus) of the Mammoth Cave. Examples of closely limited Articulata may not be 
so striking, yet the Blind Crawfish of the Mammoth Cave and the many parasites 



found 



nly upon or within certain species of animals, are very remarkable in 



this 



pect. Among Mollusks, I would remark the many species of land shells, ascer- 



tained by Professor Adams to 



ly in Jamaica, 1 among the "West India Islands 



Even 



among Eadiata 



many 



and the species discovered by the United States Exploring Expedition upon isolated 
islands of the Pacific, and described by Dr. Gould. 2 
species might be quoted, among Echinoderms as well as among Medusae and Polypi, 
which are only known from a few localities; but as long as these animals are not 



collected with the special view of ascertaining 
tions of travellers must be received with g 



their geographical range, the indica 
>at caution, and any generalizatior 



ipecting 



of 



natural area would be premature as long as the coun- 



they inhabit have 



been more 



ely explored 



It 



nevertheless true 



as established by ample evidence, that within definite limits all the animals 
in different natural zoological provinces are specifically distinct. 



g 



What remains to 



b 



ascertained more minutely 



the precise 



g 



of each 



species, as 



well as the 



most natural limits of the different faunae 


























SECTION X. 



WIDELY 



It is not only when considering the diversification of the animal kingdom within 



■ 

limited geographical areas, that we are 



called 



upon in our investigations to admir 



of 



the unity of plan its most diversified types may exhibit ; the identity of stru 

these types is far more surprising, when we trace it over a wide range of country 

and within entirely disconnected areas. 



Why the animals and plants of North 



America should present such a strong resemblance to those of Europ 



and Northern 



Asia, while those of Australia are 
America under the same latitudes 



so 



ly different from those of Africa and South 
ly a problem of great interest in connec- 



Contributions to Conchology, 2 Gould, (A. A.,) Mollusks, United States Ex- 

New York, 1849-50, 8vo. A series of pamphlets, ploring Expedition, under the command of Ch. 



.) 



- 

full of original information 



Wilkes 






* 



















«M „^ 


















Chap. I. 



STRUCTURE AND GEOGRAPHICAL DISTRIBUTION. 



37 



■ 

with the study of the influence of physical agents upon the character of animals 



and plants in different pai 



of the world. North America certainly does not resem 



ble Europe and Northern Asia, more than parts of Australia resemble certain parts 
of Africa or of South America, and even if a greater 



difference should be conceded 



between the latter than between the former, these disp 



are m no way com 



mensurate with the difference 



similarity of their organized being 



nally dependent 



upon the Other 



, nor m any way 

Why should the identity of species pre 




e in the Arctics not extend to the temperate zone 



zone, though different, are as 
identity of certain arctic species, in 



when many species of this 
difficult to distinguish, as it is difficult to prove the 



the different 



and when besides 



of the two zones 



mingle 



atinents converging to the north 
to a great extent at their boun 



daries ? Why are the antarctic species not identical with those of the arctic reg 
And why should a further increase of the 



ge temperatu 



pletely new types, when even in 



the Arctics, there are in 



differ 



introduce such corn- 
continents such 



strikingly peculiar types (the Khythi 

over the whole arctic area? 



for instance,) combined with those that are 



identical 



It may at first sight seem very 
r the three northern continents c 



natural that the arctic species should extend 

towards the north pole, as there can 



•ging 



be 



no 



perable 



barrier to the widest dissemination over this whole 



for 



mals living in a glacial ocean or upon parts 



of three continents which are almost 



bound 



gether by 



Yet the more we 



trace this identity in detail, the more 



surprising does it appear 



find in the Arctics as well 



ywhere else, repre 



sentatives of different types living together 
to the families of Whales, Seals, Bears, 



The arctic Mammalia belonging chiefly 
Weasels, Foxes, Ruminants and Rodents, 



have 



* 

Mammalia, the same 




eneral structure as the Mammalia of any other part 



i 

of the globe, and s< 
arctic Mollusks. the 



have the arctic Birds, the arctic Fishes, the 



Radiata when compared to the represents 



Articulata, the 
ss of the same 



types 
these 
their 



all over our globe 



This identity extends to every 



deg 



of affinity among 



animals and the plants which accompany them 



their orders, their families, and 



g 



as 



far as they have 



presentatives elsewhere, b 



ywher 



the 



same identical ordinal, family 



g 



characters 



the arctic foxes have the same 






: 



























1 I beg not to be misunderstood. I do not im- 
pute to all naturalists the idea of ascribing all the 
differences or all the similarities of the organic 
world to climatic influences; I wish only to remind 
them that even the truest picture of the correla- 
tions of climate and geographical distribution, does 
not yet touch the question of origin, which is the 



point under consideration. Too little attention has 
thus far been paid to the facts bearing upon the 
peculiarities of structure of animals in connection 
with the range of their distribution. Such investi- 
gations are only beginning to be made, as native 
investigators are studying comparatively the anatomy 
of animals of different continents. 





















A 



I 





'^ 







; — -—■■ • — - i*. 


































































' 






38 



ESSAY ON CLASSIFICATION. 



Part I 



dental formula, the same toes and claws, in fact, every g 



peculiarity which 



characterizes foxes, whether they live in the Arctics 



the temperate 



■ 

America, in Europe, in Afi 



Asia. This is equally 



or tropical 
of the seals 



whales : the same 



details of structure which characterize their genera in the 
Arctics reappear in the Antarctica, and the intervening space, as far as their natural 



distribution goes, 
not be supposed 

tural identity exi 
the teeth, of the 



This is equally 



of the birds, the fishes 



etc. 




a g 



resemblance 



By 



means 



And let it 
The struc- 



nds to the most minute details in the most intimate structure of 



of 



vessels 



hair, of the scales, in the furrows of the brain 
the folds of the internal surface of the intesti 



the ramification 
in the complica- 



were 



tion of the glands, etc., etc., to peculiarities, indeed, which nobody but a professional 
naturalist, conversant with microscopic anatomy, would ever believe could present 
such precise and permanent characters. So complete, indeed, is this identity, that 

any of these beings submitted to the investigation of a skilful anatomist, after 
having been mutilated to such an extent that none of its specific characters could 
be recognized, yet not only its class, or its order, or its family, but even its genus, 
could be identified as precisely as if it were perfectly well preserved in all its parts. 

Were the genera 

this mio-ht be considered as an extraordinary case; but there is no class of animals 



few which have a wide 



range upon 



the earth and in the ocean 



and plants which does not contain many g 



more or less cosmopolite in their 



geographical distribution 



The number of animals which have a wide distribution 






even so g 



that, as far at least as g 



are concerned, it may fairly be said 



that the majority of them have an extensive geographical rang 
the most complete evidence that, as far as any of these genera 



;. This amounts 
extends in its g 



graphical distribution, animals the structure of which 
distribution, are entirely beyond the influence 
have the power, 



notwithstanding 



is identical within this range of 

of physical agents, unless these agents 

their extreme diversity, within these very same 



geographical limits, to produce absolutely identical structures of the most diversified 



typ 



It must be remembered here, that there are g 



of Yertebrata, of Articulata 



of Mollusks, and of Radiata, which occupy the same identical and wide geographical 
distribution, and that while the structure of their respective representatives is identi- 
cal 



over the whole area, as Yertebrata, as Articulata, as Mollusks, as Eadiata, they 



are 



the same time built upon the most different pla 



I hold this fact to be 



itself a complete demonstration of the entire independence of physical agents of the 
structure of animals, and I may add that the vegetable kingdom presents a series of 



identical with these. This proves that all the higher relat 



among animals 



and plants are determined by other causes than mere physical influences 






• 












T 



■» 












Chap. I, 



STRUCTURE AND GEOGRAPHICAL DISTRIBUTION 



39 






While all the representativ 



of the same g 



are identical in structure, 1 the 



different 



sp 



of one g 



differ 




in their size, in the pro 



parts, in their ornamentation, in 
The geographical range of these 



ding 



tions of their 
elements, etc. 



their relations to the surroui 

species varies so greatly, that it cannot afford in 



itself 



for the distinction of species 



It appears further, that while some 



species which are 



scattered over very extensive areas, occupy disconnected parts of 



disconnected 



that area, other species closely allied to one another and which are generally desig 
nated under the name of representative species, occupy respectively such 
sections of these areas. The question 
assigned to every species are established 



species had 



the 



beg 



■& 



some 



then arises, how these natural boundaries 
It is now generally believed that each 
g point, from which it has spread over 



the whole range of the area it now occupies 



and that this 



indicated by the prevalence or 
of its natural area, which, on 



concentration of such species 
that account, is 



starting point is still 

1 some particular part 

called its centre of distribution or 



of creation, while at its external limits the representatives of snch speeies thin 



out, as 



were, occurring more sparsely and sometimes in a reduced 



condition 



It was a g 



prog 



in our 



science when the more extensive and precise 






knowled 



g 



of the geographical 



distribution of organized being 



forced upon its 



cultivators the 



one and the same spot upon 



that neither animals nor plants could have originated upon 
the surface of the earth, and hence have spread more 



and more widely until the whole globe became inhabited 
progress which freed science from the fetters of 



It was really an immense 



old prejudice 



for now we have 



the facts of the case before us, 

such a gradual dissemination from 

of the globe could ever have seemed to b 



it is really difficult to conceive how, by assuming 



ipot, the diversity which exists in every part 



plained. But even to g 



centres of distribution for each species 



within their natural boundaries 



distinct 
nly to 



meet the facts half way 



plants which 



find associated 



there are innumerable relations between the animals and 

•e which must be considered as primitive, 



ywhe 



And if this be so, it would 



and cannot be the result of successive adaptatio , , . . xl 

follow that all animals and plants have occupied, from the beginning, those natura 

boundaries within which they stand to one another in such harmonious relations. 



Pines have originated 



forests, heaths in 



heathers, grasses in prairies, bees in hives 



schools, buffaloes in herds, men 



herrings in 

this must have been the case m 



in nations! 3 



I 



striking proof 



the circumstance, that representative species, which 



■ 

See hereafter, Chap. II. Sect. 5. 
« Agassiz, (L.,) Geographical Distribution of 
Animals, Christian Examiner, Boston, 1850, 8vo. 
(March). 



8 Agassiz, (L.,) The Diversity of Origin of the 
Human Races, Christian Examiner, Boston, 1850, 
8vo. (February.) 






*.». . 





































' 
































;! 














































































































40 



ESSAY ON CLASSIFICATION. 



Part I. 



as distinct 



species, must 



have had from the beginning a different and distinct 

sections of areas which are simultaneously 



perfectly identical 



geographical range, frequently occupy 

inhabited by the representatives of other species, which 

the whole area. By way of an example, I would mention the Europ 

American Widgeon, (Anas 'Mareca ' Penelope and A 



and the 



the American and the 



European Ked-headed Ducks, (A. ferina and A. erythrocephah,) which inhabit respectively 
the northern parts of the Old and New World in summer, and migrate further south 



in these same 
Duck (A. mar 



tinents during winter, while the Mallard (A. Boschas) and the Scaup 
are as common in North America as in Europe. What do these 



facts tell: That all these birds originated together somewhere, where they no long 



occur, to establish themselves in the 



end within the limits they now occupy ? 



or 



that they originated either in Europe or America, where, it is true, they do not live 



all together, but at least a part of them 



that they really originated within the 




natural boundaries they occupy? I suppose with sensible readers I need only argue 

conclusions flowing from the last supposition. If so, the American Widgeon and 
American Ked-headed Duck originated in America, and the European Widgeon 

But what of the Mallard and the 



and the European Bed-headed Duck in Europe. 



Scaup, which are equally common upon the two continents; did they first appear in 
Europe, or in America, or simultaneously upon the two continents ? Without entering 
into further details, as I have only desired to lay clearly a distinct case before my 
readers, from which the character of the argument, which applies to the whole animal 
kingdom, may be fully understood, I say that the facts lead, step by step, to the 
inference, that such birds as the Mallard and the Scaup originated simultaneously and 
separately in Europe and in America, and that all animals originated in vast num- 
bers, indeed, in the average number characteristic of their species, over the whole of 
their geographical area, whether its surface be continuous or disconnected by sea, 

■The details of the 



admit 



lakes, or rivers, or by differences of level above the sea, etc. 

geographical distribution of animals exhibit, indeed, too much discrimination 

for a moment that it could be the result of accident, that is, the result of the 

accidental migrations of the animals or of the accidental dispersion of the seeds of 



plants 
beings 



The greater the uniformity of 



of these widely distributed organized 



the less probable does their accidental distribution appear 



I confess that 



nothing has ever surprised 



me so 



much 



as 



to see the perfect identity of the most 



delicate microscopic structures of animals and plants, from the remotest parts of the 
world. It was this striking identity of structure in the same types, 



this total hide 



pendence of the essential characteristics of animals and plants, of their distribution 
under the most extreme climatic differences known upon our globe, which led me to 
distrust the belief, then almost universal, that organized beings are influenced by 



physical causes to 



degree which 



may essentially modify their character 
















*> 



« 
























Chap. I. 



LOCALIZED STRUCTURES 



41 



SECTION XI 








COMMUNITY OF STRUCTURE AMONG ANIMALS LIVING IN THE SAME REGIONS. 







The most interesting result of the earliest investigations of the fauna of Australia 
the discovery of a type of animals, the Marsupialia, prevailing upon this conti- 



nental island, which 



unknown in almost every other part of the world 



Every 



Quadrumana in New Holland 



student of Natural History knows now that there are no 

neither Monkeys, nor Makis : no Insectwora, neither Shrews, nor Moles, nor Hedgehog 



no true Camivora} neither Bears, nor Weasels 



Foxes, nor Viverras, nor Hy 



nor Wild Cats ; no Edentata, neither Sloths, nor Tatous, nor Ant-eaters, nor Pangolins 
no Pachyderms, neither Elephants, nor Hippopotamuses, nor Hogs, nor Ehinoceroses 



nor Tap 



Wild Horses 



no 



Ruminantia, neither Camels 



Llamas 



D 



nor Goats, nor Sheep, nor 



Bulls etc., and yet the Mammalia of Austral 



are 



almost as diversified as those of any other c 

■ 

who has studied them with particular care 
diversity of stri 
indeed, we find 



g 



herbivorous 



among 



the marsupial animals analog 



tinent. In the words of Waterhouse, 2 
the Marsupialia present a remarkable 

i 

jarnivorous, and insectiverous species; 

>us representations of most of 



6 



the other orders of Mammalia. The Quadrumana are represented by the Phelan 
the Camivora by the Dasyuri, the Insectwora by the small Phascogales, the Rwmnantia 
by the Kangaroos, and the Edentata by the Monotremes. The Cheiroptera are not 




presented by any known marsupial animals, and the Rodents are represented by 



igl i^mx^ lJ 



the hiatus is 



filled up, however, in both cases, by placental 



species, for Bats and Rodents 



bly numerous 



Australia, and, if we 



pt 



the Dog, which 



probable has been 



duced by man, these 



the Only pi 



cental Mammalia found in that continent." 



Nevertheless, all these animals have 



common some 



most striking anatomical characters, which distinguish them from all 



other Mammalia, and stamp them as 



one of the most natural groups of that class; 



their mode of reproduct 



and the connection of the young with the mother 



difFere 



also, is the 



of their brain 



3 



'g 



Now, the suggestion that such peculiarities could be produced by physical i 
is for ever set aside by the fact that neither the birds nor the reptiles, nor, indeed 
any other animals of New Holland, depart in such a manner from the ordinary char 



Doubts are entertained respecting the origin of 



Marsupial: 



the Dingo, the only beast of prey of New Holland. pedia of Anat. and Physiol., London, 1841, 8vo., and 

2 Waterhouse, (G. A.,) Natural History of the several elaborate papers by himself and others, 

Mammalia, London, 1848, 2 vols. 8vo., vol. i., p. 4. quoted there. 

6 



















V £ ^.Ir r* 



l r 























i 












I 


































42 



ESSAY ON CLASSIFICATION. 



Part I. 



of their representatives in other parts of the world 



unless it could be shown 



that such agents have the power of discrimination, and may produce, under the same 



conditions, beings which agree and others which do 



gree with those of different 



continents ; 



to speak ag 



of the simultaneous occurrence in that 



of other heterog 



tyP 



of Mammalia, B 



I 

and Rodents, which occur 



there 



well 



ywhere else in other 



Nor is New Holland the only part 

among themselves, and yet 



of the world which nourishes animals highly diversified 

presenting common characters strikingly different from those of the other member 



of their type, circumscribed within definite geographical areas. 



Almost 



y part 



of the globe exhibits some such group either of animals or of plants, and every 



of organized bein 



some native natural group, more or less extensive, 



more or less prominent, which is circumscribed within peculiar geographical limits 
Among Mammalia we might quote further the Quadrumana, the representatives 



which, though greatly diversified in the Old as well as in 

agree respectively in many important points of their structure; also the Edentata 



of 



the New World, differ and 

of 



South America. 

Among birds, the Humming Birds, which constitute a very natural 
and numerous family, all of which are nevertheless confined to America o 
Pheasants are to 



beautiful 




as 



the 



the Old World. 1 Among Reptiles, the Crocodiles of the Old World 
compared to those of America. Among fishes, the family of Labyrinthici, which is 
confined to the Indian and Pacific Oceans, that of Goniodonts, which is limited to the 

the Pacific. The compar- 

examples 



fresh waters of South America, as that of Cestraciontes 



ative 



atomy of Insects is not sufficiently far advanced to furnish 




of this kind; among Insects, however, remarkable for their form, which are limited 



may 



to particular regions, 

of the Cape of Good Hop 



b 



quoted the g 



Mormoly 



of Java, the Pneumora 



the Belostoma of North Ame 



the Fulg 



of China 



etc. 



The 



geographical distribution of Crustacea has been treated in such a masterly 
manner by Dana, in his great work upon the Crustacea of the United States Explor- 
ing Expedition, Vol. XIII., p. 1451, that I can only refer to it for numerous examples 
of localized types of this class, and also as a model how to deal with such subjects. 



Among Worms 



the Peripates of Guiana deserv 



to be mentioned 



Among Ceph 



lopods, the Nautilus in Amboyna. Among Gasteropoda, the genus Io in the western 
waters of the United States. Among Acephala, the Trigonia in New Holland, certain 
Naiades in the United States, the Aetheria in the Nile. Among Echinoderms, the 
Pentacrinus in the West Indies, the Culcita in Zanzibar, the Amblypneustes in the 



Pacific, the Temnopl 



the Indian Ocean, the Dendraster 



the western coast 






, 






































1 What are called Pheasants in America do not 
even belong to the same family as the eastern Pheas- 



ants. The American, so-called, Pheasants are gen- 
nine Grouses. 



^■^■^■■■■■^^■■■■■■■iflB^^^^H 



^^v^n* i 












I 






\ 



Chap. I. 



S 



CONNECTION AM 



ANIMALS 



4° 



o 



of North America. Among Acalephs, the Berenice of New Holland. Among Polyp 



the true Fungidse 



the Indian and Pacific Oceans, the Eenilla in the Atlantic, etc. 



Many more examples mig 



be quoted, were 



our knowledge of 



distribution of the lower animals more precise, 
whether high or low, aquatic or terrestrial, there 



peculiar 



which are 



the geographical 
But these will suffice to show that 
are types of animals remarkable for 
circumscribed within definite limits, and this locali- 



zation of special structures is a striking confirmation of the view expressed already 
in another connection, that the organization of animals, whatever it is, may be 
adapted to various and identical conditions of existence, and can in no way be con- 
sidered as originating from these 



conditions 



SECTION XII 



SEEIAL CONNECTION IN THE STRUCTURE 



AMIMALS WIDELY SCATTERED UPON THE 



SURFACE OF OUR GLOBE. 



Ever since I have become acquainted with the reptiles inhabiting different parts 



of the world, I have been struck with a r 



emarkable fact, not yet noticed by 



far as I know, and of which 



other class exhibits such striking exampl 



This fact is that among S 



well as among Betrachians, there are families, the 



presentatives of which, though scattered all over the globe, form the most natural 



connected 



which every link represents one particular degree of development 



The Scincoids, 1 among Saurians, are one 



of these families 



It contains about one 




hundred species, referred by DumeVil and Bibron 



thirty-one genera, which, in the 



development of their organs of locomotion 

- 

illustrated in a diagram, on' the following pag 



exhibit most remarkable combinations 



Fully to appreciate the meaning 



of this diagram, it ought to be remembered 



that the animals belonging to this family 
of view. In the first place, their zoolog 
by the various combinations of the structure 
and these are the most numerous, 



considered here 
relations to one 



another 



different points 

expressed 



are 



of their legs; some having four leg 



others only two legs, which are always the hind 



g 



and others still no legs at all. Ag; 



these legs may have only one toe, or 



two, three, four, or five 



and hind leg 



and the number of toes may vary between the fore 



The classification adopted here is based upon these characters 



In 










I; 



i 










■ 



i I 















1 For the characters of the family, see Dumeril 
et Bibron, Erpetologie generate, vol. 5, p. 511. 



See also Cocteau, Etudes sur les Scincoides, Paris, 
1836, 4to. fig. 






\ 






































- 

















{ \ 














44 



ESSAY ON CLASSIFICATION. 



■ 

Part I. 














the second place, the geographical distribution is noticed. But it is at onc< 
that the home of these animals stands in no relation whatsoever to their 



pparent 
)olo2 , ical 




• 







. 



gement. 



■ 

On the contrary, the most remote g 



may occur in the same 



country, while the most closely related may live far apart. 



A , 



I 





^ 



S 







J 






\ 



f 






K. 






i 







GENERA WITH FOUR LEGS. 









( 











- 















West 









I 






.J 



i 



















[ P 






ir* 






V 



■ 
































With ft 



Tropidophorus, 1 species, Cochin- China, 
Scincus, 1 sp., Syria, North and 
Spkenops, 1 sp., Egypt. 

Dinloalossus* 6 st>.. West Indies 



well as to the hind feet: 



, 



i 

Amphiglossus, 1 sp., Madagascar. 
Gongylus, with 7 sub-genera: 

Gongylus, 2 sp., Southern Europe, Egypt, Teneriffe, Isle de France. 
Eumeces, 11 sp., East and West Indies, South America, Vanikoro, 

New Ireland, New Guinea, Pacific Islands. 
Euprepes, 13 sp., West coast of Africa, Cape of Good Hope, Egypt, 
Abyssinia, Seychelles, Madagascar, New Guinea, East Indies, 

Sunda Islands, Manilla. 
Plestiodon, 5 sp., Egypt, Algiers, China, Japan, United States. 
Lygosoma, 19 sp., New Holland, New Zealand, Java, New Guinea, 

Timor, East Indies, Pacific Islands, United States. 
Leiolopisma, 1 sp., Mauritius and Manilla. 
Tropidolopisma, 1 sp., New Holland. 
Gyclodus, 3 sp., New Holland and Java. 
Trachysaurus, 1 sp., New Holland. 
Ablepharus, 4 sp., Southeastern Europe, New Holland, Pacific Islands. 



With fi 
With fo 



fi 



Campsodactylus, 1 sp., Bengal. 



Heteropi< 



five toes to the hind feet: 

With four toes to the fore feet and 

four toes to the hind feet: 

With four toes to the fore feet and 
With three toes to the fore feet and ft 



W. Indies and Brazil. 



j Gymnophthalmus , 1 sp., 

f Tetradactylus, 1 sp., New Holland. The genus Chalcides of the allied 
| family Chalcidioids, exhibits another example of this combination. 
three toes to the hind feet: No examples known of this combination. 

























Not known. 




A 



With 



three toes to the fore feet and 
three toes to the hind feet: 



He 






Seps, 1 sp., S. Europe and N. Africa 




Nessi 



With three toes to the fore feet and two toes to the hind feet : Not known. 
With two toes to the fore feet and T Heteromeles, 1 sp., Algiers. 



three toes to the hind feet: 



Lerista, 1 sp., New Holland. 




With two 
With two 
With one 
With one 



toes to the fore feet and two toes to the hind feet: Chelomeles, 1 sp., New Holland, 
toes to the fore feet and one toe to the hind feet: Brachymeles, 1 sp., Philippine Islands 
toe to the fore feet and two toes to the hind feet: Brachystopus, 1 sp., South Africa, 
toe to the fore feet and one toe to the hind feet : Evesia, 1 sp., Origin unknown. 

































1 












Chap. I. 



SERIAL CONNECTION AMONG ANIMALS. 



45 



\ 







GENERA WITH ONLY TWO LEGS. 









■ 

No representatives are known with fore legs only; but this structural combination occurs in the allied 
family of the Chalcidioids. The representatives with hind legs only, present the following combinations : 



With two toes: Scelotes, 1 sp., Cape Good Hope. 
With one toe: Propeditus, 1 sp., Cape Good Hope 

Ophiodes, 1 sp., South America. 

Bysteropus, 1 sp., New Holland. 



and New Holland. 



Lialis, 1 sp., New Holland. 
Dibamus, 1 sp., New Guinea. 












GENERA WITHOUT ANY LEGS. 



Western 



Morea 



Acontias, 1 sp., Southern Africa, Cape Good Hope. 
Typhlina, 1 sp., Southern Africa, Cape Good Hope. 



Who 



look at this diagram, and not 



g 



in its arrangement the combi 



nations of thought? This is 
overlook the fact, that while 



obvious, that while consideri 



•5 



might almost 



was 



drawn up to classify animals preserved 



the 



Museum of the Jardin des Plantes in Paris 
these animals themselves, and is oi 



reality inscribed in Nature by 



ly read off when they 



brought together, and 



compared side by side 



But it contains an 



the series is not built up of equivalent 
combinations being 



important element for our discussion: 
presentatives in its different terms, some 



hly endowed, others numbering a few, or even a single genus, 
and still others being altogether disregarded; such* freedom indicates selection, and 



the working of the law of necessity 



And if from a contemplatio 



of this remarkable 



we 



turn our attention to 



the indications 



g 



genera, inscribed after their names, we 



to the geographical distribution of these so closely linked 

perceive at once, that they are scattered all 



the globe, but not so that there 



could be any connection between the combina 



tions of their structural characters and their horn 



The types without legs are 



found 
Hope 



m 



Europ 



Western Asia 



the types with hind leg 




Northern Africa, and at the Cape of Good 
and with one single toe, at the Cape 



of 



Good Hop 



South America, New Holland, and New Guinea 



those with 



* 

the Cape of Good Hop 



ly. Among the types with four legs the origin of 



with but 



hind foot 



each foot is unknown, those with one toe in the fore foot and 

from South Africa, those with two toes in the fore foot and 



the hind foot 



in the Philipp 



Islands, those with two toes to all four 



feet in New Holland, those with three toes to the hind feet and two to the fore feet 


















































/ 






Mt* 



■ UKj*^ 



"»» "^ai - »■ 



r^T 



*v 



— 





m^ 








I 










46 



ESSAY ON CLASSIFICATION 



Part I 























































in Algiers and New Holland; none are known with three toes to the fore feet and 
two to the hind feet. Those with three toes to the four feet inhabit Europe, North- 
em Africa, and New Holland. There are none with three and four toes, either in 
the fore feet or in the hind feet. Those with four toes to the four feet live in 
New Holland: those with five toes to the fore feet and four to the hind feet, in 



Beng 



and with four toes in 



the fore feet and five in the hind feet, in Africa 



the West Indies, the Brazils, and New Holland 



Those with five toes to all four 



feet have the widest distribution, and yet they are so scattered that no single zoolog- 
ical province presents any thing like a complete series ; on the contrary, the mixture 



of some of the representatives 



perfect feet with others which have them rudi 



mentary, in almost every fauna, excludes still more decidedly the idea of an influence 

of physical agents upon this development. 

me traced among the Batrachians, 



Another similar 



series, not 



less striking, may 



for the characters of which I may 



refer to the works of Holbrook, Tschudi, and 



Baird, 1 even though they have not presented them 



this connection, as the charac 



of the genera will of themselves suggest their order, and further details upon 
this subject would be superfluous for my purpose, the more so, as I have already 
discussed the gradation of these animals elsewhere. 2 

Similar series, though less conspicuous and more limited, may be traced in every 

- 

class of the animal kingdom, not ( 
representatives of past geological a 




among 



the living types, but also among the 




which adds to the interest of such series in 



showing, that the combinations include not 




the element of space 



indicating 



omnipresence, but also that of time, which involves prescience 



The series of Crinoids 



that of Brachiopods through all geological 



■g 



that of the Nautiloids, that of 



Ammonitoids from the Tri 
from the lowest beds up 



formations 



the Cretaceous formation inclusive, that of Trilobites 

to the Carboniferous period, that of Ganoids through all 

the series of 



among living animals in the class of Mammalia 



the Dieritiarades 



Monkeys in the Old World especially, that of Carnivora from the Seals, through the 

in the class of Birds, that of the Wading Birds, 

; in the class of Fishes, that of Pleuronectidae and 

; in the class of Insects, that of Lepidoptera from 



&*"& 



Plantigrades 

and that of the Gallinaceous Birds i 
Gadoids, that of Skates and Sharks 
the Tineina to the Papilionina; in 



the class of C 



that of the Decapods in 



particular ; in the class of Worms, that of the Nudibranchiata or that of the Dorsibran 































1 Holbrook, (J. E.,) North American Her- 
petology, Philadelphia, 1842, 4to. ;• 5th vol. 
Tschudi, (J. J.) Classification der Batrachier, 



■ 

Acad. Nat. Science, of Philadelphia, 2d series, 

vol. L, 1849, 4to. 

2 Agassiz, (L.,) Twelve Lectures on Compara- 



Neuchatel, 1838, 4to.— Baird, (Sp. F.) Revision tive Embryology, Boston, 1849, 8vo.; p. 8. 
of the North American Tailed Batrachia, Journal 

























Chap. I. 



SIZE OF ANIMALS. 



47 



chiata especially 



in the class of Cephalopoda, that of the Sepioids 



the 



of 



the 



Gasteropoda, that of the Nudibranchiata in particular ; 
of the Ascidians and that of the Oysters in the widest 
derms, those of Holothurise and Asterioids ; in the class of Acaleph 

Hydroids 

deserve 

to the points under considerat 

reference to space and to time 



ss of Acephala, that 
the class of Echino- 



that of the 



the class of Polyps, that of the Halcyonoids, of the Atraeoids, etc., etc., 



particular attention, and may be studied with g 



advantag 



refer 



For 



ywher 



do we observe in them, with 



B 



it 



ght not to be 



nected series, there are others m 

diversity of which involves other considerations 



the thoughtful combinations of an active mind, 
looked, that while some types represent strikingly con- 
■ in which nothing of the kind seems to exist, and the 



SECTION 



XIII. 



BETWEEN 



The relation between the size 
^stigated, though even the most 



and structure of animals has been very little 
perficial survey of the animal kingdom may 



tisfy any 



that there 



a 



decided relation between size and 



structure among 



them 



Not that I mean to assert that size 



and structure form parallel series, or 



■ 

that all animals of one branch 



agree very 

organizatior 



losely with one another in 



not denned 



those of the same class or the same order, 

reference to size. This element of their 

within those limits, though the Vertebrata, as a whole, 






ger than 



either Articulata, Mollusks, or Kadiata ; thong 



Mammal 



are 



"g 



than Birds, Crustacea larger than Insects ; though Cetacea 



larger than Herbivo 



se larger than Carnivora, etc. 



the 

animals, size acquires a real importan 

are essentially distinguished by their form, as 



The true limit at which 



the 



K 



of 



far as the structure of animals is concerned 



that of families, that is, the groups which 

if form and size were correlative as 

ves of natural families 



The represented 



are indeed closely similar 



that 



ipect 



the extreme differences are hardly any 




double. A few examples, 

natural families, will show this. Omitting mankind, on 

\ it embraces 
of Bats, of 



where tenfold within these limits, and frequently 

■ 

selected among the most # . 

n , , . ,. T • i, -rv^rvTif hp made against the idea that 

account of the objections which mignt oe ni<*uc ^ ^ ^ 

* 

any original diversity, let us 



Insectiv 



of Car 



consider the different families of Monkey 
of Rodents, of Pachyderms, of 



Birds, the Vultures, the Eagles, the Falcons. 
Warblers, the Humming Birds, the Doves 



Ruminants, etc., among 
Owls, the Swallows, the Finches, the 
"Wrens, the Ostriches, the Herons, 




















I 



































'#*■ 



















I 






48 



ESSAY ON CLASSIFICATION. 



Part I. 




































the Plovers, the Gulls, the Ducks, the Pelicans ; among Eeptiles, the Crocodiles, the 
different families of Chelonians, of Lizards, of Snakes, the Frogs proper, the Toads, 



etc.; among Fishes 



Sharks and Skates, the Herrings, the Codfishes, the Cyp 



nodonts, the Chgetodonts, the Lophobranchii, the Ostracionts, etc.; among Insects, the 



Sphingoids or the Tineina, the Long 



the Coccinellina, the Bomboidae or the 



Brachonidae; among Crustacea, the Cancroidea or the Pinnotheroidaa, the Limuloidae 
or the Cypridoidae, and the Rotifera; 1 among Worms, the Dorsibranchiata or the 



Naioidse; among Mollusks, the Stromboidge or the Buccinoidae, the Helicinoidae 



the 



Limnseoidae, the Chamacea or the CycladoidaB 



amon 



Radiata, the Asterioidse and 



the Ophiuroidae, the Hydroids and the Discophoraa, the Astraeoidaa and the Actinioidae. 

to show what are the limits within 

1 it is natural to infer, that 



Having thus recalled some facts which g 



which size and structure are more directly connected, 2 it is 

since size is such an important character of species, and extends distinctly its cycle 

of relationship to the families or even further, it can as little be supposed to be 



determined by physical 



■g 



as 



the structure itself with which it is so closely 



connected, both bearing similar relations to these agents. 

Life is regulated by a quantitative element in the structure of all organized 

- 

beings, which is as fixed and as precisely determined as every other feature depend- 



ing more upon 



the quality of the org 



or their parts 



This shows the more 



distinctly the presence of a specific, immaterial principle in each kind of animals 
and plants, as all begin their existence in the condition of ovules of a microscopic 
size, exhibiting in all a wonderful similarity of structure. And yet these primitive 
ovules, so identical at first in their physical constitution, never produce any thing 
different from the parents ; all reach respectively, through a succession of unvarying 
changes, the same final result, the reproduction of a new being identical with the 



parents. How does it then happen, that, if physical 



■g 



have such a 



powerful 



influence in shaping the character of organized beings, we see no trace of it in the 

* 

innumerable instances in which these ovules are discharged in the elements in which 
they undergo their further development, at a period when the germ they contain, 



' 



i 




















1 See Dana's Crustacea, p. 1409 and 1411. 

2 These remarks about the average size of ani 



least bearing upon the question of origin or even 
the maintenance of any species, but only upon 



mals in relation to their structure, cannot fail to individuals, respecting which more will be found in 



meet with some objections, as it is well known, 
that under certain circumstances, man may modify 
the normal size of a variety of plants and of 
domesticated animals, and that even in their natural 



Sect. 16. Moreover, it should not be overlooked 
that there are limits to these variations, and that 

y 

though animals and plants may be placed under 

influences conducive to a more or less voluminous 



state occasional instances of extraordinary sizes growth, yet it is chiefly under the agency of 



man 



occur. 



But this neither modifies the character- 



istic average, nor is it a case which has the 






that such changes reach their extremes. (See also 



Sect. 15.) 


























1 








I 






Chap. I. 



SIZE AND THE ELEMENTS. 



49 



has not yet assumed any of those more determined characteristics which distinguish 



the full-grown animal or 



the perfe 



plant 



? 



D 



phy 



know a law of the 



that it could 



material world which presents any such analogy to these phenomena, 

be considered as accounting for them? 

In this connection it should be further remembered, that these cycles of size 
characteristic of different families, are entirely different for animals of different types, 
though living together under identical circumstances. 



SECTION XIV 



KELATIONS BETWEEN THE SIZE OF ANIMALS, AND THE MEDIUMS IN WHICH THEY LIVE 



It has just been remarked, that animals of different types, even when living 
together, are framed in structures of different size. Yet, life is so closely combined 
with the elements of nature, that each type shows decided relations, within its own 



limits, to these elements as far as size is 



concerned. 1 The aquatic Mammalia, as a 



whole, are larger than the terrestrial ones ; so are the aquatic Birds, and the aquatic 
Reptiles. In families which are essentially terrestrial, the species which take to the 



water are generally larger than those which remain permanently terrestrial, as for 
instance, the Polar Bear, the Beaver, the Coypu, and the Capivara. Among the 

different families of aquatic Birds, those of their representatives which are more ter- 
restrial in their habits are generally smaller than those which live more permanently 
in water. The same relation is observed in the different families of Insects which 

number aquatic and terrestrial species 
animals, the fresh water types are 



It is further remarkable, that among aquatic 
inferior in size to the marine ones; the marine 



Turtles are all larger than the largest inhabitants of our rivers and ponds, the more 
aquatic Trionyx larger than the Emyds and among these the more aquatic Chelydra 

larger than the true Emys, and these generally larger than the more terrestrial 
Clemmys or the Cistudo. The class of Fishes has its largest representatives in the 
sea; fresh water fishes are on the whole dwarfs, in comparison to their marine 
relatives, and the largest of them, our Sturgeons and Salmons, go to the sea. The 
same relations obtain among Crustacea ; to be satisfied of the fact, we need only 



compare our 



Crawfishes with the Lobsters, our Apus with Limulus, etc. Among 















■ 





















1 Geoffroy St. Hilaire, (Isid.,) Recherches 

zoologiques et physiologiques sur les variations 
de la taille chez les Animaux et dans les races 

7 



humaines, Paris, 1831, 4to. — See also my paper 
upon the Natural Relations between Animals and the 
Elements, etc., quoted above, p. 32. 


















ii* 













50 



ESSAY ON CLASSIFICATION 



Paet I, 


























Worms, the Earthworms and Leeches furnish a still wider 



ge of comparisons 



. i 



when contrasted with the marine types. Among Gasteropods and Acephala, this 
obtains to the same extent ; the most gigantic Ampullariae 



and Anodontae are small 



in 



comparison to certain Fusus, Voluta, Tritonium, Cassis, Strombus, or to the 



Tridacna. Among Eadiata even, which are all marine 



with the 



pti 



of the 



s 



single genus Hydra, this rule holds good, as the fresh water Hydroids are among the 

- 

smallest Acalephs known. 

This coincidence, upon such an extensive scale, seems to be most favorable to 
lew that animals are modified by the immediate influence of the elements; 

is no causal 



the 7 

yet I consider it as affording 



of the most striking proofs that there 



connection between them. Were it otherwise, the terrestrial and the aquatic repre- 
sentatives of the same family could not be so similar as they are in all their 

- 

essential characteristics, which actually stand in no relation whatsoever to these 



elements 



quatic mode of 



the sea. 



What constitutes the Bear in the Polar B 



is not its adaptation to an 



What makes the Whales Mammalia, b 



relation 



What constitutes Earthworms, Leeches, and Eunice members of 



class 



of structure which 



has no more connection with their habitat, than the peculiarities 

unite Man, Monkeys, Bats, Lions, Seals, Beavers, Mice, and Whales into one class. 



Moreover, animals of different types living 



the same element have no sort of 



dmilarity, as to size. 



The 



quatic Insects, the aquatic Mollusks fall in with the 



average size 



'& 



of their class, as well as the aquatic Keptiles and the aquatic Birds, or 



the 



quatic Mammalia 



but there is no common 



<g 



for either terrestrial or 



\ 



quatic animals of different classes taken 



gether, and in this lies the evidence that 



ganized beings are independent of the mediums in which they live, as far as their 

created they were made to suit 



g 



is concerned, though 



plai 



that when 



the element in which they were placed 



To me 



these facts show, that the phemomena of life are manifested m the 



physical world, and not through or by it ; that organized beings are 



made to 



•Id 



conquer and assimilate to themselves the materials of the morga: 

they maintain their original characteristics, notwithstanding the unceasing action 



that 



of 



physical agents upon them 



And I confess I cannot comprehend 



how b 






SO 



entirely independent of these influences, could be produced by them 



' 












































Chap. L 



IMMUTABILITY OF SPECIES. 



51 









i 



SECTION XV 



PERMANENCY OF SPECIFIC PECULIARITIES IN ALL ORGANIZED BEINGS. 



was a great step in the progress of science when it was ascertained that 
have fixed characters, and that they do not change in the course of time. 



It 

species 

But this fact, for which we are in 



importance since 



debted to Cuvier, 1 has acquired a still greater 

it has also been established, that even the most extraordinary 

conditions under which animals may be 



changes in the mode of existence and in the 



placed, have no more 



influence upon their essential characters than the lapse of time. 

these two subjects are too well known now to require 



The facts bearing upon 
special illustration. I will, therefore, allude only to a few points, to avoid even the 
possibility of a misapprehension of my statements. That animals of different geo- 
logical periods differ specifically, en masse, from those of preceding or following forma- 
tions, is a fact satisfactorily ascertained. Between two successive geological periods, 
then, changes have taken place among animals and plants. But none of those pri- 
mordial forms of life, which naturalists call species 
during any of these periods. 



f 



are known to have changed 



It cannot be denied, that the species of different 



successive periods are supposed by some 
features from changes which have taken place 



naturalists to derive their distinguishing 

in those of preceding ages; but this 
supposition, supported neither by physiological nor by geological evidence, 
and the assumption that animals and plants may change in a similar manner during 
one and the same period, is equally gratuitous. 



is a mere 



On the contrary, it is known by 

the evidence furnished by the Egyptian monuments, and by the most careful com- 
parison between animals found in the tombs of Egypt with living specimens 



of the 



w 

same species obtained in the same 



country, that there is not the shadow of a differ- 



ence 



between them, for a period of about five thousand years 



These comparisons, 
far as it has been possible to carry 



first instituted by Cuvier, have proved, that as 

back the investigation, it does not afford the beginning of an evidence that species 

of time if the comparisons be limited to the same great 

2 there lhave existed 



change 



in the course 



cosmic epoch. 



Geology only shows that at different periods 



1 Cuviee, (G.,) Eecherches sur les ossements 
fossiles, etc., Nouv., edit. Paris, 1821, 5 vols., 4to., 
fig., vol. i., sur l'lbis, p. cxli. 

2 I trust no reader will be so ignorant of the 
facts here alluded to, as to infer from the use of during one or any of these periods. It is almost 
the word « period " for different eras and epochs of incredible how loosely some people will argue upon 



great length, each of which is characterized by dif- 
ferent animals, that the differences these animals ex- 
hibit, is in itself evidence of a change in the species. 
The 



question is, whether 



any changes take place 



















■ 












1 

















|j| 


















111 









>• 







f 


















. 







































52 



ESSAY ON CLASSIFICATION. 



Part I 



different species 



but no transition from those of a precedi 



into those of the 



following epoch has 



been noticed anywhere; and the question alluded to here 



to be distinguished from that of the origin of the differences in the bulk of species 
belonging to two different geological eras. The question we are now exammm 




involves only the fixity or mutability of species durin 



© 



one 



poch, one era, one 



period in the history of our globe 



And nothing furnishes the slightest argument 





































this point from a want of knowledge of the facts, 
even though they seem to reason logically. A dis- 

■ 

tinguished physicist has recently taken up this sub- 
ject of the immutability of species, and called in 
question the logic of those who uphold it. I will 
put his argument into as few words as possible, 
and show, I hope, that it does not touch the case. 
"Changes are observed from one geological period 
to another ; species which do not exist at an earlier 
period are observed at a later period, while the for- 
mer have disappeared ; and though each species may 
have possessed its peculiarities unchanged for a lapse 
of time, the fact that when long periods are con- 
sidered, all those of an earlier period are replaced 
by new ones at a later period, proves that species 



room to another, he beholds changes as great as those 
the paleontologist observes in passing from one sys- 
tem of rocks to another. But because these works 
bear a closer resemblance as they belong to one or 
the other school, or to periods following one another 
closely, would the critic be in any way justified 
in assuming that the earlier works have changed 
into those of a later period, or to deny that they 
the works of artists living and active at the 



are 



time of their production? The question about the 
immutability of species is identical with this sup- 
posed case. It is not because species have lasted 
for a longer or shorter time in past ages, that nat- 
uralists consider them as immutable, but because in 
the whole series of geological ages, taking the entire 
change in the end, provided a sufficiently long period lapse of time which has passed since the first intro- 



of time is granted." I have nothing to object to the 
statement of facts, as far as it goes, but I maintain 



that the conclusion is not logical. 



duction of animals or plants upon earth, not the 
slightest evidence has yet been produced that species 

We 



It is true that are actually transformed one into the other. 



species are limited to particular geological epochs; 
it is equally true that, in all geological formations, 
those of successive periods are different, one from 
the other. But because they so differ, does it fol- 
low that they have changed, and not been exchanged 
for, or replaced by others? The length of time 
taken for the operation has nothing to do with the 
argument. Granting myriads of years for each pe- 
riod, no matter how many or how few, the question 
remains simply this: When the change takes place, 
does it take place spontaneously, under the action of 
physical agents, according to their law, or is it pro- 
duced by the intervention of an agency not in that 
way at work before or afterwards? A comparison 
may explain my view more fully. Let a lover of 
the fine arts visit a museum arranged systematically, 
and in which the works of the different schools are 
placed in chronological order ; as he passes from one 



only know that they are different at different periods, 
as are works of art of different periods and of differ- 
ent schools ; but as long as we have no other data to 
reason upon than those geology has furnished, to this 
day, it is as unphilosophical and illogical, because 
such differences exist, to assume that species do 
change, and have changed, that is, are transformed, 
or have been transformed, as it would be to main- 
tain that works of art change in the course of time. 
We do not know how organized beings have origi- 
nated, it is true; no naturalist can be prepared to 
account for their appearance in the beginning, or for 
their difference in different periods; but enough is 
known to repudiate the assumption of their transmu- 
tation, as it does not explain the facts, and shuts out 
further attempts at proper investigations. See Ba- 
den Powell's Essays, quoted above; p. 412, et 

■ 

seq., and Essay 3d, generally. 


























Chap. I. 



IMMUTABILITY OF SPECIES. 



53 



favor of their mutability; on 



the contrary, every modern investigation 1 has only 



gone to confirm the results first obtained by Cuvier, and his views that species 



are 



fixed 



It is something to be able to show by monumental evidence, and by direct 



com 



parison, that animals and plants have underg 



no change for a period of about 



five thousand years 



2 



This result has had the greatest influence upon the prog 



of 



especially with reference to the consequences to b 



drawn from the occur- 



rence in the series of geological 



formations of organized being 



highly diversified 



each epoch as those of the present day 



• 3 it has laid the foundation for the 



viction, now universal among 
existence for innumerable ages, and 



well informed naturalists, that this globe has been in 



became inhabited cannot be 



which we belong 



ted 



years 



elapsed since it first 
Even the length of the period to 



that the length of time 



still a problem, notwithstanding the precision with which 



There 



however, many 



ystems of chronology would fix the creation of man 

drcumstances which show that the animals now living have been for a much long 



period inhabitants of our 

trace the formation and growth of our 



globe than is generally supposed 



coral reefs, especially 



It has been possible 

Florida, 5 with sufii- 



precision to ascertain that 



must take about 



ght thousand years for one of 



those 
There 



. » •. e ^nimn +n the level of the surface 
coral walls to rise from its foundation to tne ieve 



of the ocean. 



around the 



southernmost extremity of Florida alone, fonr sueh reefs 



centric with one another, which can 



be shown to have g 



up, one after the 



other 



, ■, • • ^ +fco fir^t of these reefs an age of over thirty 
This gives for the beginning of the nrst 01 uie* s j 

, , i i_ T ™WTi tbev were all built up are the same 

years: and yet the corals by which tney wei v 



thousand 

identical species in all of them 

can obtain in any branch of physical 



These facts, then, furnish as direct evidence 



quiry, that some, at least, of the species 



of 



animals now 



g, have been in 



existence over thirty thousand years, and have 



undergone the slightest chang 



during the whole of that period. 6 And yet these 






1 Runth, Recherches sur les plantes 



trouvees 



dans les tombeaux egyptiens, Ann- des scien. nat., vol. 

viii., 1826, p. 411. 

It is not for me to discuss the degree of reli- 
ability of the Egyptian chronology ; but as far as it 
goes, it shows that from the oldest periods ascer- 
tained, animals have been what they are now. 

8 See my paper upon The Primitive Diversity, 

etc., quoted above, p. 25. 

4 Nott & Gliddon, Types of Mankind, p. 653. 

5 See my paper upon the Reefs of Florida, soon 
to be published in the Reports of the United States 



Coast Survey, extracts of which are already printed 
in the Report for 1851, p. 145. 

6 Those who feel inclined to ascribe the differ- 
ences which exist between species of different geo- 
logical periods to the modifying influence of physi- 
cal agents, and who look to the changes now going 



on 



among the 



living for the support of such an 



opinion, and may not be satisfied that the facts just 
mentioned are sufficient to prove the immutability 
of species, but may still believe that a longer period 
of time would yet do what thirty thousand years 
have not done, I beg leave to refer, for further con- 



I 

































































■.""V^ 



'•— ~*-^ 



VP^ 







: 




























































54 



/ 



ESSAY ON CLASSIFICATION. 



Part I 



four concentric reefs are only the most distinct of that 



others 



exten- 



ely 



gated thus far, lie to the northward; indeed, the whole peninsula of 



Florida consists altogether of coral reefs annexed to one another in the course of 
time, and containing only fragments of corals and shells, etc., identical with those 
now living upon that coast. 



Now, if a width of five miles is a fair average for 



al reef 



g 



under the 



umstances under which the concentric reefs of 



Florida 



>en now to follow one another, and this regular succession should extend 
only as far north as Lake Ogeechobee, for two degrees of latitude, this would give 



about two hundred thousand years for the period of time which was necessary for 
that part of the peninsula of Florida which lies south of Lake Ogeechobee to rise 
to its present southern extent above the level of the sea, and during which no 
changes have taken place in the character of the animals of the Gulf of Mexico. 
It is very prejudicial to the best interests of science to confound questions that 
entirely different, merely for the sake of supporting a theory; yet this is con- 



are 



tly done, whenever the question of the fixity of species is alluded 



A few 



more words upon this point will, therefore, not b 
I will not 



of place here 



not enter into a discussion upon the question whether any species is found 
identically the same in two successive formations, as I have already examined it at 
full length elsewhere, 1 and it may be settled finally one way or the other, without 

! 

affecting the proposition now under consideration ; for it is plain, that if such identity 
could be proved, it would only show more satisfactorily how tenacious species are in 

- 

their character, to continue to live through all the physical changes which have 



taken place between two successive geological 



iods 



A 



& 



such identity once 



proved, would leave it still doubtful whether their representatives in two successive 
epochs are descendants one of the other, as we have already strong evidence in favor 

of the same species in separate geo- 



of the separate origin of the representatives 



graphical areas. 2 The case of closely allied, but different species occurring in succes- 
sive periods, yet limited respectively in their epochs, affords, in the course of time, a 
parallel to the case of closely allied, so-called, representative species occupying differ- 
ent areas in space, which no sound naturalist would suppose now to be derived one 
from the other. There is no more reason to suppose equally allied species following 



one another in time to be derived 



from the other: and all that has been said 






' 












sideration, to the charming song of Chamisso, entitled Mollusques fossiles, Neuchatel, 1831-45, 4to. fig. 



Tragishe Gesehichte, and beginning as follows: 

's war Einer dem's zu Herzen ging. 



Agassjz, (L.,) Monographies d'Echinodermes vivans 
et fossiles, Neuchatel, 1838-42, 4 nos., 4to. fig. 



1 Agassiz, (L.,) Coquilles tertiaires reputees Agassiz, (L.,) Recherches sur les Poissons fossiles, 
itiques avec les especes vivantes, Nouv. Mem. de Neuchatel, 1833-44, 5 vols., 4to., atlas, fol. 

2 See Sect. 10, where the case of representative 
species is considered. 



la Soc. Helv. des sc. nat. Neuchatel, 1845, vol. 7, 

Agassiz, (L.,) Etudes critiques sur les 



4to. fig. 





























I 



; 



















Chap. I. 



IMMUTABILITY OF SPECIES. 



55 






■ 






preceding paragraphs respecting the differences observed between species occurring 



in different geographical areas, 
each other in the course of time 



pplies with the same force to species 



succeedin s 



When domesticated animals and 



vated plants are mentioned as furnishing 



evidence of the mutability of species, the circumstance is 



tantly 



looked 



or 



passed 



silence that the first point to be established respecting them, in ord 



to justify any inference from them ag 
that each of them has originated from 



the fixity of species, would be to show 
common stock, which, far from being the 



case, is flatly contradicted 




the positi 



knowled 



5 



we 



have that the 



of 



al of them, at least, are owing 



to the entire amalgamation of different species 



i 



The Egyptian monuments show further that many of those 



called varieties which 



are 
bee 



ipposed to be the product of 
known to man: at all 



time 



old as any other animals which have 



of the existence of any 

animals, already as different among 

quite possible that the 



events we have no tradition, no monumental evidence 
wild animal older than that which represents domesticated 



It is, therefore 



different 



species, more 



or less mixed now, as 



themselves as they are now. 2 
of domesticated animals were originally distinct 
the different races of men are. Moreover, 



vated plants, nor 



neither domesticated animals nor cub 
proper subjects for an investigation re 
all involve already the question at issue in the premises 



the races of men, are the 



pecting 



the fixity or mutability of species, as 



which 



assumed 



intro- 



ducing them as evidence in the 
domesticated animals, which are 



"With reference to the different breeds of our 
known to be produced by the management of man, 



well 



certain varieties of our 



vated plants, they must 



be well distinguished 



ght 



we 



from permanent races, which, for a 
are the result of the fostering care 

■ 

influence and control the human mind has over 



know, may be primordial; for breeds 



of man- they are the product of the limited 

organized beings, and not the free 



product of mere physical agents. 



They show, therefore, that even the least impor 



tant 



changes which 



may take place during one 



and the same cosmic period among 



animals and 



the immediate 




are 



oiled by 



llectual power, and do not result from 



of physical causes. 



So far, then, from disclosing 



the effects of physical agents, whatever 



g 



are 



known to take 




m 



the course of time amon 



ganized beings appear as the 



result of an intellectual power 



and g 



erefore, to substantiate the view that all 



the differ 



observed amon 



«• finite beings are ordained by the action of the 
Supreme Intellect, and not determined by physical causes. This position is still 

gthened when we consider that the differences which exist between differ- 



mor 



ent races of domesticated 



and the 



of our cultivated plants 













.'. 












II 


























1 Our fowls, for instance. 



2 Nott & Gliddon, Types of Mankind, p. 386. 
















*&r* 



v^ T1 I; ^ | | -» ^J 































56 



ESSAY ON CLASSIFICATION. 



Part I. 


































,' 













as among the races of men, are permanent under 



the most diversified climatic influ- 
ences ; a fact, which the extensive migrations of the civilized nations daily proves more 

■ 

extensively, and which stands in direct contradiction to the supposition that such or 



similar influences could 



produced them 



When considering the subject of domestication, in particular 



ght further to 



be remembered, that 



every 



of men has its own peculiar kinds of domesticated 



animals and of cultivated plants, which exhibit much fewer varieties among them 
in proportion as those races of men have had little or no intercourse with other 



races, than the domesticated animals of those 
mixture of several tribes. 



which have been formed by the 



It 



often stated that the ancient philosophers have solved satisfactorily all the 



g 



questions interesting to man, and that modern 



though they have 



- 

grasped with new vigor, and illuminated with new light, all the phenomena of the 
material world, have added little or nothing in the field of intellectual progress. Is 
this true? There is no question so deeply interesting to man as that of his own 
origin, and the origin of all things. And yet antiquity had no knowledge concerning 
it; things were formerly believed either to be from eternity, or to have been created 
at one time. Modern science, however, can show, in the most satisfactory manner, 
that all finite beings have made their appearance successively and at long intervals, 



and that each kind of organized beings has existed for a definite period of time in 



past 



g 



and that those now living are of comparatively recent origin. 



At the 



same time, the order of their succession 



and their immutability during such cosmic 

periods, show no causal connection with physical agents and the known sphere of 



action of these 



g 



in nature, b 



g 



in favor of repeated interventions on 



the part of the Creator. It seems really surprising, that while such an intervention 
is admitted by all, except the strict materialists, for the establishment of the laws 
regulating the inorganic world, it is yet denied by so many physicists, with reference 



to the 
rather 



introduction of organized being 



different successive periods. Does this 



to show the imperfect acquaintance of these 



gators with the condi 



go 
under which life is manifested, and with the essential difference there is between 



the phenomena of the organic and 



of the physical world, than to furnish any 



evidence that the organic world is the product of physical causes ? 











































t 



-*i*S* ■ 








/ 


















■ « 



Chap. I. 



HABITS OF ANIMALS, 



57 



ii 






















SECTION XVI 



BETWEEN ANIMALS AND PLANTS AND THE SURROUNDING WORLD 



Every animal and plant stands in 



certain definite relations to the 



ounding 



orld, some however, 



domestic animals and cultivated plants, being capabl 



of adapting themselves to various 



condit 



this pliability 



characteristic featur 



ions more readily than others; but even 
These relations are highly important in a 



systematic point of view. 



and deserve the most careful attention, on the p 



of 



naturalists. Yet, the direction 



and embryology began to 



S 



omy 

has been very unfavorable to the 

their relations to one another and 

especially exhibited. We have to go back 



ological studies have taken since comparative anat- 
absorb almost entirely the attention of naturalists, 



of the habits of animals, in which 



the conditions under which they live, are more 



.1 



the authors of the preceding century, 






for the most interesting accounts of the 
there 



habits of animals, as among modern writers 



are 



few who have devoted their chief attention to this subj 



2 



So little, 



indeed, is its importance now 

history are hardly acknowledged as peer 



appreciated, that the students of this branch of natural 

5 by their fellow investigators, the anat- 



omists and physiologists, or the systematic zoolog 
knowledge of the habits of animals, it will neve 

i • 

degree of precision the true limits of all those species 



And yet, without a thorough 



be possible to 



with any 



which descriptive zoologists 



have of late admitted with so much confiden 



in their works. And after all, what 



does it matter 



that thousands of species more 



less, should be described 



and entered in our systems, if we 
defect of the works relating to the 
detract from their value 



A 



very common 



anecdotic character, or the 



occasion for 



know nothing about them? 

habits of animals has no doubt contributed to 

and to turn the attention in other directions: their purely 

cumstance that they are too frequently made the 

Nevertheless, the importance of this 



ating personal adventures 



VI 








in 





















i 





































1 Reaumur, (R. Ant. i>e,) Memoires pour 
servir a l'histoire des Insectes, Paris, 1834-42, 6 vol. 

— Rosel, (A. J.,) Insectenbelustigungen 



5 vols. 8vo. — Kirby, (W.,) and Spence, (W.,) 
An Introduction to Entomology, London, 1818-26, 



4to. fig. 



4 vols. 8vo. &g. 



4 vols. 4to. fig. 



Lenz, (H. 0.,) Gemeinnutzige 

Rat- 



Buffon, Naturgeschichte, Gotha, 1835, 4 vols. 8vo. 

zenburg, (J. Th. Ch.,) Die Forst-Insekten, Ber- 



Nurnberg, 1746-61, 

(G. L. LeClerc de,) Histoire naturelle generate 

et particuliere, Paris, 1749, 44 vols. 4to. fig. 

2 Audubon, (J. J.,) Ornithological Biography, Harris, (T. W.,) Report on the Insects injurious 
or an Account of the Habits of the Birds of the to Vegetation, Cambridge, 1841, 1 vol. 8vo. ; the 



lin, 1837-44, 3 vols. 4to 



%•> 



and supplement. 















United States of America, Edinburgh, 1831-49, 

8 



most important work on American Insects. 










t 



























~<^f «•**>- 

































■ 
I 



58 



ESSAY ON CLASSIFICATION. 



Part I. 













. 



I 



















■ 

kind of investigation can hardly be overrated ; and it would be highly desirable that 
naturalists should turn again their attention that way, now that comparative anatomy 



and physiology, as well as embryology, may sugg 



many new topics of inquiry 



and the progress of physical geography has laid such a broad foundation for 

/ 

researches of this kind. Then we may learn with more precision, how far the 
species described from isolated specimens are founded in nature, or how far they 



may b 



only a particular 



■g 



of growth of other species; then we shall know 



what is yet too little noticed, how extensive the range of variations is among ani- 
mals, observed in their wild state, or rather how much individuality there is in each 
and all living beings. So marked, indeed, is this individuality in many families, — and 
that of Turtles affords a striking example of this kind, — that correct descriptions of 
species can hardly be drawn from isolated specimens, as is constantly attempted to 
be done. I have seen hundreds of specimens of some of our Chelonians, among 






which there were not two identical. And truly, the limits of this variability con- 






stitutes one of the most important characters of many species; and without precise 



information upon this point for every g 



it will never be possible to have a 



solid basis for the distinction of species. Some of the most perplexing questions 
in Zoology and Palaeontology might long ago have been settled, had we had more 
precise information upon this point, and were it better known how unequal in this 
respect different groups of the animal kingdom are, when compared with one 
another. "While the individuals of some species seem all different, and might be 

■ 

+ 

described as different species, if seen isolated or obtained from different regions, those 
of other species appear all as cast in one and the same mould. It must be, there- 
fore, at once obvious, how different the results of the comparison of one fauna with 
another may be, if the species of one have been studied accurately for a long 
period by resident naturalists, and the other is known only from specimens collected 



by chance travellers; or, if the fossil representatives 
with living animals, without both faunae having first 
same standard. 1 

Another deficiency, in most works relating to the 
the absence of general views and of comparisons, 
how far animals related by their structure are similar in 



of one period are 



pared 



been revised according to the 



habits of animals, consists in 
We do not learn from them, 

their habits, and how far 






1 In this respect, I would remark that most of 



Such 



cases should be altogether rejected in the 



the cases, in which specific identity has been affirmed investigation of general questions, involving funda- 

species, or between the mental principles, as are untrustworthy observations 



between living and fossil 



fossils of different 



geological periods, belong to 



always in other departments of science. Compare 
families which present either great similarity or further, my paper upon the primitive diversity and 
extraordinary variability, and in which the limits of number of animals, quoted above, in which this 
species are, therefore, very difficult to establish. point is specially considered. 









M^BM 



































Chap. I. 



HABITS OF ANIMALS. 



59 



these habits are the expression of their structure. Every species is described as if 
it stood alone in the world; its peculiarities are 
trast more forcibly with all others. 



mostly exaggerated, as if to con- 
Yet, how interesting would be a comparative 



study of the mode of life of closely allied species 



how 



be drawn of the resemblance there is in 



this 



spect b 



itive a picture might 
species of the same 



genus and of the same family 
struck with the similarity in 



The more I learn upon this subject, the 



am I 



the very movements, the g 



habits, and even in 



the 



of the 



of animals belonging to the same family ; that 



between animals ag 



m 



the main in form 



ment 



hs to say, 

structure, and mode of develop- 

of animals 



A minute study of these habits, of these movements, of the voice 
fail, therefore, to throw additional light upon their natural affinities 



While I thus acknowledge the great importar 



of such 



gations with refer 



the systematic arrangement 



of animals, I cannot help regretting deeply, that 



they 
secure 



are not more highly valued with reference to the information they might 

nff the animals themselves, independently of any system. How much 



ipect 



is there not left to study with respect to every species 



after 



nam 



and classi- 



fied 



No one can read Nauman's Na 



feeling that natural history would b 



History of the German Birds without 
much further advanced, if the habits of all 



other animals had been as 



ly investigated and as minutely recorded; and yet 






that work contains hardly any thing of importa 
arrangement of birds, 
sary to discuss upon a 



ice with reference to the systematic 

ly possess the most elementary information neces- 

scientific basis the question of the instincts and in general 



We 



the faculties of animals, and to compare 
not only because so few animals have bet 
much fewer still have been watched durm 



B 



and with those of man, 1 
tvestigated, but because so 
their earlier periods of life, when their 



them together 

i thoroughly i: 



i 



faculties are first developin 
age is in every living being 
that the habits of animals a 



and yet how attractive and instructive this growing 



Who could, for 



believe for a moment long 



any 



deg 



determined by the circumstances under 



which they live, after having seen a 



little Turtle of the g 



Chelyd 



still 



enclosed in its 



o 



shell which it hardly fills half-way, with a yolk bag as lar 



8 



as 



itself hanging from its lower surface and 



ped 



amnios and 



allantois, 



with the eyes shut, snapping as 



fiercely as if it could bite without killing itself 



Who 



watch 



Sunfish (Pomotis 



hoverin 



t> 



gs and protect 



them for weeks, or the Catfish (Pimelodus Catus) move about with its young, like 




















II 






II 





















II 

i 















1 Scheitlin, (P.,) Versuch einer 



Thierseelenkunde, Stuttgart und Tubingen, 

2 vols. 8vo. — Cuvier, (Fred.,) Resume analyt- 

ique des observations sur l'instinct et Intelligence 



vollstandigen des animaux, par R. Flourens, Ann. Sc. Nat., 2de 

1840, ser., vol. 12. 

2 See, Part III., which is devoted to the Em- 
bryology of our Turtles. 


































■*<* *» 



?■■»-. 



2s 

















60 



ESSAY ON CLASSIFICATION. 



Part I. 































a hen with her brood, without remaining 
them in these acts is of the same kind 



suckling, or the child to its mother 
recognized such a similarity between < 



satisfied that the feeling which prompts 
as that which attaches the Cow to her 
Who is the investigator, who having once 



faculties of Man and those of the hig 



animals can feel prepared, in the present stage of our knowled 
where this community of nature ceases? And yet to ascertah 



S 



e, to trace the limit 
the character of all 



these faculties there is but one road, the study of the habits of animals, and a 
comparison between them and the earlier stages of development of Man. I confess 
I could not say in what the mental faculties of a child differ from those of a 



young 



Chimpanzee 



Now that we have physical maps of almost every 



the 



average temperature of 



now that the 
most characte] 



g 



part of the globe, 1 exhibiting 
hole year and of every season upon land and sea; 
elevation of the continents above the sea, and that of the 



parts of their surface, their 



their plains, their table-land 



their mountain systems, are satisfactorily known ; now that the distribution of moisture 

* 

in the atmosphere, the limits of the river systems, the prevailing direction of the 

the ocean, are not only investigated, but mapped 



winds 



course of the currents of 



down, even in school atlases; now that the geological structure of nearly all parts 
of the globe has been determined with tolerable precision, zoologists 




zoologists have the widest 
field and the most accurate basis to ascertain all the relations which exist between 
animals and the world in which they live. 

Having thus considered the physical agents with reference to the share they may 
have had in calling organized beings into existence, and satisfied ourselves that 



they are not the cause of their origin 



it now remains for us to examine more 



particularly these relations, as an established fact, as conditions in which animals and 
plants are placed at the time of their creation, within definite limits of action and 
reaction between them; for though not produced by the influence of the physical 
world, organized beings live in it, they are born in it, they grow up in it, they 
multiply in it, they assimilate it to themselves or feed upon it, they have even a 
modifying influence upon it within the same limits, as the physical world is sub- 
servient to every manifestation of their life. It cannot fail, therefore, to be highly 

these connections, even without any reference 
to the manner in which they were established, and this is the proper sphere of 

of animals. The behavior of each kind 
towards its fellow-beings, and with reference to the conditions of existence in which 
it is placed, constitutes a field of inquiry of the deepest interest, as extensive as it is 



interesting and instructive to trace 



investigation in the study of the habits 












1 Berghaus, Physikalischer Atlas, Gotha, 1838 Atlas of Natural Phenomena, Edinburgh, 1848, 
et seq., fol. — Johnston, (Alex. Keith,) Physical 1 vol. foL 















; 


























































Chap. I. 



HABITS OF ANIMALS 



61 



complicated. 






When properly investigated, especially within the sphere which con- 
stitutes more particularly the essential characteristics of each species of animals and 
plants, it is likely to afford the most direct evidence of the unexpected independence 
of physical influences of organized beings, if I mistake not the evidence 



myself been able to collect. 



What can 



I have 



there be more characteristic of different 



species 



of animals than their motions, their plays, their affections, their sexual rela- 



tions, their care of their young 



the dependence of these upon their parents, their 



instincts, etc., etc.; and yet there is 



nothing in all this which depends in the slight- 



est 



degree 



upon the nature or 
they live. Even their organic 
degree unsuspected, though this is 
closest connections with the world around. 

Functions have so long been considered as 
that it has almost become an axiom in 
identical functions presuppose identical organs 

comparative anatomy are 
there 



the influence of the physical conditions m which 
functions are independent of these conditions to a 

* 

the sphere of their existence which exhibits the 



the test of the character of organs, 
comparative anatomy and physiology, that 

Most of our general works upon 



never was a more 



more generally adopted. 

is the more surprising as every one 



divided into chapters according to this view. And yet 

incorrect principle, leading to more injurious consequences, 

That naturalists should not long ago have repudiated it, 



must 



have felt again 



and again how unsound 



it is. 



The 



organs 



of respiration and circulation of fishes afford a striking example. 



How long have not their 



ills been considered as 



now long nave not tneir gins ueuu w**^— .. — 

the higher Vertebrata, merely because they are breathing organs; 



the equivalent of the lungs of 



and yet these gills 



are 



formed 



m a 



very 



different way from the lungs ; they bear very different rela- 



tions to the vascular system; and it is 
ously with lungs, as in some full-grown 

in all Vertebrata. 



stages of development, 



now known that they may exist simultane- 
Batrachians, and, in the earlier embryonic 

any doubt now, 



no longer be 



■n 



that they are essentially different organs, 

their nature and cannot constitute an argument m 



There can 
and that their functions afford no test of 



The same 



may be said of the vascular system of the fishes. 



icle and the 



heart as representing the right aun 

the blood it contains to the gills, in the same manner as 

pels 



favor of their organic identity. 

Cuvier 1 described their 

because it propels 



right ventricle, 



the 



right ventricle 



pro- 



the blood to the lungs of 



the warm 



blooded 




yet embryology has 



taught us that such a comparison 



fishes, is unjustifiable, 



The air sacs 



as 



based upon the special relations of the heart of 
of certain spiders have also been considered 

only 



lungs, because they perform similar respiratory functions, and yet they 



are 



modified trachese, 2 which are 



constructed upon such a peculiar plan, and stand in 



1 Cuvier, (G.,) Regn. Anim., 2de edit., vol. 2, 



p. 122. 



3 Leuckardt, (R. ? ) Ueber den Bau raid die 
Bedeutung der sogenannten Lungen bei den Arach- 



,i 















I 









I 















. i 


























































































62 



ESSAY ON CLASSIFICATION. 



Part I. 



such different relations to the peculiar kind of blood of the Artieulata, 1 that no 
homology can be traced between them and the lungs of Vertebrata, no more 
than between the so-called lungs of the air breathing Mollusks, whose aerial 
tor j cavity is only a modification of the peculiar kind of gills observed in other 



respira- 



Mollusks. 



Examples might easily be multiplied; I will, however, only allude further 



to the alimentary canal of Insects and Crustacea, with its glandular appendag 
formed in such a different way from that 



of Verteb 



or Mollusks, or Eadiata 



their legs and wings, etc., etc. I might allude also to what has been called the foot 
in Mollusks, did it not appear like pretending to suppose that any one entertains 
still an idea that such a name implies any similarity between their locomotive 
apparatus and that of Vertebrata or Articulata, and yet, the very use of such a 
name misleads the student, and even some of the coryphees of our science have 
not freed themselves of such and similar extravagant comparisons, especially with 



refer 



to the solid parts of the frame of the lower animals 



The identification of functions and 



'g 



was a natural consequence of the 



prevailing ideas respecting the influence physical agents were supposed 



have 



up 



ganized being 



But 



as 



soon as it is understood, how 



different the organs may 



be, which in animals perform the same function, organization is at once brought 
such 



a position to physical agents as makes it utterly impossible to maintain 



g 



- 

connection betwe 



them. A fish, a crab, a mussel 



g 



m 



the 



any 
same 



waters, breathing at the same source, should have the same respiratory organs, if the 

animals live had any thing to do with shaping their organi- 

as to assume that the same 



elements in which these 



zation. I suppose no one can be so short-sighted, 

physical agents acting upon animals of different types, must produce, in each 



organs, 



and not to perceive that such an assumption implies the very existence of 
these animals, independently of the physical agents. But this mistake recurs so 
constantly in discussions upon this and similar topics, that, trivial as it is, it requires 

to be rebuked. 3 On the contrary, when acknowledging an intellectual conception, 



































niden, in Siebold und Kolliker's Zeitschrift, f. 
wiss. Zool., 1849, I., p. 246. 



shared in the physical doctrines more or less pre- 
vailing now, respecting the origin and existence of 



1 Blanchard, (Em.,) De la circulation dans les organized beings. Should the time come when my 



Insectes, Compt. Rend., 1847, vol. 24, p. 870. 



present efforts may appear 



like fighting against 



Agassiz, (L.,) On the Circulation of the Fluids in windmills, I shall not regret having spent so much 



Insects, Proc. Amer. Asso., for 1849, p. 140. 



labor in urging my fellow-laborers in a right direc- 



2 Carus, (C. G.,) Von den Ur-Theilen des tion; but at the same time, I must protest now 
Knochen- und Schalengerustes, Leipzig, 1828, 1 vol., and for ever, against the bigotry spreading in some 



fol., p. 61-89. 



3 



I hope the day is not far distant, when zoolo- 



gists and botanists will 



equally disclaim having 



quarters, which would press upon science, doctrines 
not immediately flowing from scientific premises, 
and check its free progress. 


























Chap. I. 



RELATIONS OF INDIVIDUALS 



63 






as the preliminary step in 



the existence not only of all 



ed bein 



5 



every thing in 



how natural to find that while 



introduced 



but of 
in the 




in 



the complication and the details of structure of animals, their relations to 



the 



surrounding media are equally diversified, and consequently the same funct 



may be performed by the most different 



pparatu 



I 










^ 



SECTION XVII 
















KELATIONS OF INDIVIDUALS TO ONE ANOTHEE. 



The relations in which 



individuals of the same species of animals stand to one 
another are not less determined and fixed than the relations of species to the sur- 
rounding elements, which we have thus far considered 



The 



hich individ 



ual animals bear 



one another are 



of such a character, that they ought 



■g 



g 



/ 



to have been considered as proof sufficient that 
been called into existence by another agency 
reflective mind. 



10 organized being could ever have 
than the direct intervention of a 



It is in a measure conceivable that 



duce something like the body of the lowest kinds of animals or 



physical agents might pro- 
ants, and that 




under identical circumstances the same thm 
again, by the repetition of the same process 
possibilities of the case, it 
further supposition is, that such agencies 




and 



may have been produced again 
but that upon closer analysis of the 



should not have at once 



ppeared how 



g 



the 



what they had just called into 



that they could 



produ 



could delegate the power of reproducing 
3 those very beings, with such limitations, 

to under- 



any thing but themselves, I am at a loss 



stand 



It will no more 



do to suppose that from simpler structures such a pro 



cess may end in 
addition of possibilities i 
power can only be an 



the production of the most perfect, as every step implie 



an 



>t even included 
act of intellige 



the 



g 



Such a deleg 



of 



while between the product 



of 



an 



indefinite number of organized being 



as 



the result of a physical law, and the repro 



duction of the 



same 



tion. 
their 



The successive g 



ganized beings by themselves, there is no necessary connec- 
•nerations of any animal or plant cannot stand, as far as 



g 



is concerned, in any causal relation to physical ag 



if these 



g 



the power of 



deleg 



have already been produ 
physical law that the resultant is 



g their own action to the full extent to which they 
a the first appearance of these beings ; for it is a 



qual to the for 



pplied. If any new being 



has 



ever 



been produced by such agencies, how could the successive 
enter, at the time of their birth, into the same relations to these age 



g 



as 



their 































WT 






■ - 








































































64 



ESSAY ON CLASSIFICATION. 



Part I. 



ancestors, if these beings had not in themselves the faculty of sustaining their char- 
acter, in spite of these agents ? Why, again, should animals and plants at once begin 



to 
ent 



decompose under the very influence of all those agents which have been subse 



the maintenance of their life, as soon 



life 



if life 



limited 



deter- 



mined by them 



■ 

There exist between individuals of the same species relations far more complicated 



than those already alluded to, which go still further to dispr 



any possibility of 



causal dependenc 



of 



ganized beings upon physical agents. The relations 



which the maintenance of species is based, throughout the animal kingdom 



upon 
1 the 



universal antagonism of 



sex, and the infinite diversity of these connections in differ 



ent typ 



have 



% 



■g 



to do with external cond 



• , • 



indicate only rel 



of individuals to individuals, beyond their 



of existence ; they 

* 

onnections with the 



material world in which they live 

physical causes, when physical ag 



way bearing upon 



iphe 



How, then, could these relations be the result of 
s are known to have a specific sphere of action, 
of phenomena ? 



For the most part, the relations of individuals to individuals are unquestionably 
an organic nature, and, as such have to be viewed in the same light as any other 



of 

structural feature : but there is much, also 



these connections that par 



of 



a 



of the word 



psychological character, taking this expression in the widest sense 

When animals fight with one another, when they associate for a common purpose, 
when they warn one another in danger, when they come to the rescue of one 
another, when they display pain or joy, they manifest impulses of the same kind as 



are considered among the moral attributes of man. 



The range of their 



passions 



is 



even as 
differenc 



extensive as that of the human mind, and I am at a loss to perceive a 



of kind between them, however much they may differ in de 



and 



m 



the manner in which they are expressed. The gradations of the moral faculties 



anion 




higher animals and man are, moreover, so imperceptible, that to deny to 



the first a certain sense 



of 



ponsibility and consciousness, would certainly be 



an 



exaggeration of the difference between animals and man. There exists, besides, as 
much individuality, within their respective capabilities 
as every sportsman,, or every keeper of 



among animals as 



men 



menageries, or 



can 



every farmer and shepherd 
tify who has had a large experience with wild, or tamed, or domesticated 



animals. 



1 



t 

This argues strongly in favor of the existence in every animal of an immaterial 



i See J. E. Eidinger's various works illustra- naturelle des Mammiferes, Paris, 1820-35, 3 vols, 

tive of Game Animals, which have appeared under fol.-^LENZ, (H. O.,) Gemeinnutzige Naturgeschichte, 

different titles, in Augsburg, from 1729 to 1778.— Gotha, 1835, 4 vols. 8vo.— Bingley, (W.,) Animal 

Geoffroy St. Hilaire, et Cuvier, (Fr,,) Histoire Biography, London, 1803, 3 vols. 8vo. 









































































\ 


































Chap. L 



RELATIONS OF INDIVIDUALS. 



65 



principle similar to that which; by its excellence and superior endowments, places 
man so much above animals. 1 Yet the principle exists unquestionably, and whether 



structural similarity or difference alone that the re- 
lations between man and animals have to be con- 
sidered. The psychological history of animals shows 
that as man is related to animals by the plan of his 



known to them were the Red Monkey, xrj@og, the 
Baboon, xvvoxecpalog, and the Barbary Ape, m&qxog. 
A modern translation of Aristotle, it is true, makes 
him say that monkeys form the transition between 
man and quadrupeds ; (Aristoteles, 
schichte der Thiere, von Dr. F. Strack, Frankfurt- 



Naturge- 



no 



establish a distinct kingdom 






1 It might easily be shown that the exaggerated homo a simia internoscatur." But it is not upon 
views generally entertained of the difference exist- 
ing between man and monkeys, are traceable to the 
ignorance of the ancients, and especially the Greeks, 
to whom we owe chiefly our intellectual culture, of 
the existence of the Orang-Outang and the Chim- structure, so are these related to him by the char- 
panzee. The animals most closely allied to man acter of those very faculties which are so tran- 

scendent in man as to point at first to the necessity 
of disclaiming for him completely any relationship 
with the animal kingdom. Yet the natural history 
of animals is by no means completed after the so- 
matic side of their nature has been thoroughly in- 
vestigated ; they, too, have a psychological individ- 
uality, which, though less fully studied, is neverthe- 
less the connecting link between them and man. I 
cannot, therefore, agree with those authors who would 
disconnect mankind from the animal kingdom, and 

for man alone, as 
Ehrenberg (Das Naturreich des Menschen, Berlin, 
1835, fol.) and lately I. Geoffroy St. Hilaire, (Hist, 
nat. generate, Paris, 1856, Tome 1, Part 2, p. 167,) 
have done. Compare, also, Chap. II., where it is 
shown for every kind of groups of the animal kingdom 
that the amount of their difference one from the 
other never affords a sufficient ground for removing 
any of them into another category. A close study 
of the dog might satisfy every one of the similarity 
of his impulses with those of man, and those im- 
pulses are regulated in a manner which discloses 
psychical faculties in every respect of the same kind 
as those of man; moreover, he expresses by his 
voice his emotions and his feelings, with a precision 
which may be as intelligible to man as the articu- 
lated speech of his fellow men. His memory is so 
retentive that it frequently baffles that of man. And 
though all these faculties do not make a philosopher 
of him, they certainly place him in that respect 
upon a level with a considerable proportion of poor 
humanity. The intelligibility of the voice of ani- 
mals to one another, and all their actions connected 
with such calls are also a strong argument of their 



am-Main, 1816, p. 65;) but the original says 
such thing. In the History of Animals, Book 2, 
Chap. V., we read only, ma ds rav £ohx># tTta^o- 
TSQifyi rrjv cpvaiv rep re av&QWTtco y.ai toig tztQaitoaiv. 
There is a wide difference between "partaking of 
the nature of both man and the quadrupeds/' and 
" forming a transition between man and the quadru- 
peds.'' The whole chapter goes on enumerating the 
structural similarity of the three monkeys named 
above with man, but the idea of a close affinity is 
not even expressed, and still less that of a transi- 
tion between man and the quadrupeds. The writer, 
on the contrary, dwells very fully upon the marked 
differences they exhibit, and knows as well as any 
modern anatomist has ever known, that monkeys have 



four hands. 



fl 



-»/ 



? 



. ... Idlovg ds rovg Ttodag . slat yaQ oiov %€iQsg 

ixeydlai. Kcd ol ddxrvloi wgnsQ oi %<nv X 8l Q™ v > ° W a ? 
l^axQorarog • xou to xdrco rov rtobbg %eiqi opoiov, nlrp 
im to prjxog to xrfi %Ei()bg titi ret ia^ara rstvov xad'a- 
tzsq Qivaq. Tovro ds In dxQOv cxhiQOttQW, xaxwg 
Y.&1 d\iv§Qwg ixifLOVfievov TtreQvrjV. 

It is strange that these clear and precise dis- 
tinctions should have been so entirely forgotten m 
the days of Linn^us that the great reformer in 
Natural History had to confess, in the year 1746, 
that he knew no character by which to distinguish 
man from the monkeys. Fauna Suecica, Prsefat. p. 2. 

• "i 



" Nullum characterem adhuc eruere potui, unde perceptive power, and of their ability to act spon- 


















■ 









9 



I ! 



. i 
















y 








Zt 































































































































. 















66 



ESSAY ON CLASSIFICATION. 



Part I. 



it be called soul, reason, or instinct, it presents in the whole range of organized 

of phenomena closely linked together; and upon it are based not 



beings a series 



only the higher manifestations of the mind, but the very permanence of the specific 
differences which characterize every organism. Most of the arguments of philosophy 
in favor of the immortality of man apply equally to the permanency of this principle 

May I not add, that a future life, in which man should be 
deprived of that great source of enjoyment and intellectual and moral improvement 



in other living beings. 



* 

world, would 



which result from the contemplation of the harmonies of an org 

■ 

involve a lamentable loss, and may we not look to a spiritual concert of the com 
bined worlds and all their inhabitants 



in presence of their Creator as the highest 



conception of paradise ? 



SECTION XVIII 






























METAMORPHOSES OF ANIMALS. 



The study of embryology is of very recent date; the naturalists of the past 
century, instead of investigating the phenomena accompanying the first formation and 
growth of animals, were satisfied with vague theories upon reproduction. 1 It is true 






















taneously and with logical sequence in accordance the agglutinating, and the inflecting languages. The 
with these perceptions. There is a vast field open Felidce mew : the roaring of the lion is only ano- 
ther form of the mewing of our cats and the other 



for investigation in the relations between the voice 



and the actions of animals, and a still more inter- species of the family. The Equina neigh or bray: 

esting subject of inquiry in the relationship between the horse, the donkey, the zebra, the dow, do not differ 

the cycle of intonations which different species of much in the scale of their sounds. Our cattle, and the 

animals of the same family are capable of uttering, different kinds of wild bulls, have a similar affinity 

which, as far as I have as yet been able to trace in their intonations ; their lowing differs not in kind, 

them, stand to one another in the same relations as but only in the mode of utterance. Among birds, 

the different, so-called, families of languages (Schle- this is, perhaps, still more striking. Who does not 

■ 

gel, (Fr.,) Ueber die Sprache und Weisheit der distinguish the note of any and every thrush, or of 



Indier, Heidelberg, 1808, 1 vol. 8vo. — Humboldt, 



the warblers, the ducks, the fowls, etc., however nu- 



(W. v.,) Ueber die Kawi-Sprache, auf der Insel merous their species may be, and who can fail to 



Java, Berlin, 1836-39, 3 vols. 4to. Abh. Ak. d. Wis- perceive the affinity of their voices ? And does 

sensch. — Steinthal, (H.,) Grammatik, Logik und this not indicate a similarity also in their mental 

Psychologie, Berlin, 1855, 1 vol. 8vo.) in the human faculties? 
family. All the Canina bark ; the howling of the 

wolves, the barking of the dogs and foxes, are 



1 Buffon, (G. L. LeClerc de,) Discours sur 
la nature des Animaux, Geneve, 1754, 12mo. ; also 



only different modes of barking, comparable to one in his Oeuvres completes, Paris, 1774-1804, 36 vols. 



another in the same relation as the monosyllabic, 



4to. 



























V~ ' 























. 






Chap. I. 



METAMORPHOSES OF ANIMALS 



67 



the metamorphoses of Insects became very 




the subj 



of most remarkable 



observations, 1 but so little was it then known that all animals undergo great chang 



■ 

from the first to the last stages of 



the 



was considered 



a distinguishing character of Insects 



ipect, are however 



dy so g 



those which undergo a complete 

three successive different forms, as larvae, pupae, and perfect 



growth, that metamorphosis 

The differences between Insects, in that 

that a distinction was introduced between 

metamorphosis, that is to say, which appear in 

insects, and those with 



an incomplete metamorphosi 



or 



whose larvae differ little from the perfect insect. 



The 



ge of these changes is yet so limited in some insects, that it is not only 
greater, but is even much smaller than in many representatives of other classes. 



the chang 



We may, therefore, well apply the term metamorphosis to designate all 
which animals undergo, in direct and immediate succession, 2 during their growth, 

are correctly qualified for 



whether these changes are 



great or small, provided they 



each typ 



The study of embryology, at first limited to the 



g 



of the chang 



the 



which the chicken underg 

of the animal kingdom; and so dilig 



g, has gradually extended to every type 
and thorough has been the study, that 



the first author who ventured upon an extensive illustration of the whole field 



C. E. von Baer, has already presented the 



ubject in such a clear manner, and 



drawn general conclusions so 



accurate and so comprehensive, that all subsequent 



esearches in this department of our 



may 



be considered only as a further 



development of the facts first noticed by him and of the results he has already 

he who laid the foundation for the most extensive 



deduced from them 



It was 



1 Swammerdam, (J.,) Biblia Naturae, sive His- 
toria Insectorum, etc., Lugduni-Batavorum, 1737-38, 
3 vols. fol. fig. — Reaumur, (R. Ant. de,) Memoires 
pour servir a l'Histoire des Insectes, Paris, 1734—42, 

6 vol. 4tO. fig. ROESEL VON ROSENHOF, (A. J.,) 

Insectenbelustigungen, Nurnberg, 1746—61, 4 vols. 
4to. fig. 

2 I say purposely, " in direct and immediate suc- 
cession," as the phenomena of alternate generation 
are not included in metamorphosis, and consist chiefly 
in the production of new germs, which have their 
own metamorphosis; while metamorphosis proper 
relates only to the successive changes of one and 

the same germ. 

8 Without referring to the works of older writers, 
such as DeGraaf, Malpighi, Haller, Wolf, Meckel, 
Tiedemann, etc., which are all enumerated with many 



others in Bischoff's article " Entwickelungsges- 
chichte/' in Wagner's Handworterbuch der Physio- 
lo°ie, vol. 1, p. 860, 1 shall mention hereafter, chiefly 
those published since, under the influence of Dollin- 
ger, this branch of science has assumed a new char- 
acter: — Baer, (C. E. v.,) Ueber Entwickelungs- 
geschichte der Thiere, Konigsberg, 1828-37, 2 vols. 
4to. fig. The most important work yet published. 
The preface is a model of candor and truthfulness, 
and sets the merits of Dollinger in a true and beauti- 
ful light. As text-books, I would quote, Burdach, 
(C. F.,) Die Physiologie als Erfahrungswissenschaft, 
Leipzig, 1829-40, 6 vols. 8vo.; French, Paris, 
1837-41, 9 vols. 8vo. — Muller, (J.,) Handbuch der 
Physiologie des Menschen, Coblenz, 1843, 2 vols. 8vo. 

■ 

4th edit. ; Engl, by W. Baly, London, 1837, 8vo. 
Wagner, (R.,) Lehrbuch der Physiologie, Leip- 



































AM 































"Hit V^M 























W 






68 



ESSAY ON CLASSIFICATION. 



Part I. 






















































generalizations respecting the mode of formation of animals ; for lie first discovered 



in 1827, the ovarian 
there 



egg of Mammalia, and thus showed for the first time, that 
is no essential difference in the mode of reproduction of the so-called vivip- 
arous and oviparous animals, and that man himself is developed in the same manner 

The universal presence of eggs in all animals and the unity of their 



the animals 



g 



which was soon afterwards fully ascertained, constitute, in my opinion 
discovery of modern times in the natural sciences. 1 



It was, indeed, a gigantic step to demonstrate such an identity in the material 



b 



of the develoi 



of 



when their anatomical structure was already 



known to exhibit such radically different plans in their full-grown 



From that 



time a more and more extensive 



■g 



of the manner in which the first 



g 



is formed in these 



eggs, 



and the embryo develop 



itself 



how its 



'g 



grow gradually out of a homogeneous mass; what changes, what complications, what 
connections, what functions they exhibit at every stage; how in the end the young 

and becomes a new, independent being, 

inquiry. To ascertain all this, 



animal assumes 



final form and 



could not fail to be the 



many 



most interesting subject of 



animals as possible, belonging to the most different types of the animal 
kingdom, became soon the principal aim of all embryological investigations; and it 
can truly be said, that few sciences have advanced with such astonishing rapidity, 
and led to more satisfactory results. 

For the actual phases of the mode of development of the different types of the 



animal kingdom, I must refer to the special works upon this subj 



2 



no general 




















zig, 1839-42, 2 vols. 8vo. — Valentin, (G.,) Hand- ner, (R.,) Prodromus Historic generationis Hominis 



buch der Entwickelungsgeschichte, etc., Berlin, 1835, 
1 vol. 8vo. — Lehrbuch der Physiologie des Men- 

■ 

schen, Braunschweig, 1843, 2 vols. 8vo. — Longet, 



atque Animalium, etc., Lipsias, 1836, 1 vol., fol., fig. 
Icones physiologies, Lipsiae, 1839, 4to. fig. 
2 The limited attention, thus far paid in this 



(F. A.,) Traite de Physiologie, Paris, 1850, 2 vols. country to the study of Embryology, has induced 



8vo. 



Kolliker, (Alb.,) Microscopische Anatomie 
des Menschen, Leipzig, 1840-54, 2 vols. 8vo. fig. 
See also Owen's Lectures, etc., Siebold und Stan- 



me to enumerate more fully the works relating to 
this branch of science, than any others, in the hope 
of stimulating investigations in that direction. There 
Nius's Lehrbuch, and Carus's Morphologie, q. a. exist upon this continent a number of types of ani- 
p. 27, and p. 18. I might further quote almost every mals, the embryological illustration of which would 
modern text-book on physiology, but most of them add immensely to the stock of our science ; such 

I are the Opossum, the Ichthyoid Batrachians, the 

acquaintance with the subject, that I omit purposely Lepidosteus, the Amia, etc., not to speak of the 



are so evidently mere compilations, exhibiting no 



to mention any other elementary works. 

1 Baer, (C. E. a,) De Ovi Mammalium et 
Hominis Genesi, 



Konigsberg, 1827, 4to., fig. 



opportunities which thousands of miles of sea-coast, 
everywhere easily accessible, afford for embryologi- 
cal investigations, from the borders of the Arctics 



Purkinje, (J. E.) Symbols ad ovi avium historiam to the Tropics. In connection with Embryology 



ante incubationem, Lipsias, 1830, 4to. fig. — Wag 



the question of Individuality comes up naturally. 































































Chap. I. 



METAMORPHOSES OF. ANIMALS. 



69 



treatise embracing the most recent investigations having 



yet been published 



and 



I must take it for granted, that before forming a definite opinion upon the corn- 



par 



instituted hereafter between 



growth of animals, and 



grada 



tion among full-g 



animals 



the order of succession of the fossils characterist 



of different geological periods, the necessary information respecting 
been gathered by my readers, and sufficiently mastered 
it freely. 



these changes h 



enable them to deal with 



The embryology of Polypi has been very little studied thus far; what we know 

these animals relates chiefly to the family of Actinoids. 1 

has the form of a little club-shaped or pear-shaped 



of the embryonic growth of 



When the 



young is hatched, it 



body, which soon 



assumes the appearance of the adult, from which it differs only by 

The mode of ramification and the multiplication by buds 



having few tentacles, 
have, however, been carefully and minutely studied in all the families of this class. 2 
Acalephs present phenomena so peculiar, that they are discussed hereafter in a 

either polyplike or resemble more immediately 



special section. Their young 3 are 



See upon this subject: — Leuckart, (Rud.,) Ueber 
den Polymorphisms der Individuen oder die 
Erscheinung der Arbeitstheilung in der Natur, 
Giessen, 1851, 4to. — Reichert, (C. B.,) Die mono- 
gene Fortpflanzung, Dorpat, 1852. — Huxley, (Th. 
H.,) Upon Animal Individuality, Ann. and Mag. 
Nat. Hist. 2d ser., 1852, vol. 9, p. 507. — Forbes, 
(Ed.,) On the supposed Analogy between the Life 

■ 

of an Individual and the Duration of a Species, Ann. 
and Mag. Nat. Hist, 2d ser., 1852, vol. 10, p. 59. 
Braun, (Al.,) Das Individuum der Pflanze, q. a 



Betrachtungen iiber die Erscheinung; 



© 



/ 



jungung in der Natur, Freiburg, 1849, 4to. fig. 

1 Sars, (M.,) Beskrivelser og Jagttagelser over 
nogle maerkelige eller nye i Havet ved den Ber- 
genske Kyst levende Dyr, etc., Bergen, 1835, 4to. 
Fauna littoralis Norvegise, Christiania, 1846, fol. 
fig. — Eathke, (H.,) in Burdaeh's Physiologie, vol. 
2d, 2d edit. p. 215. — Zur Morphologie, Reisebemer- 
kungen aus Taurien, Riga und Leipzig, 1837, 4to., 

Agassiz, (L.,) Twelve Lectures, etc., p. 40, 



fig. 



et seq. 



2 See Dana's Zoophytes, and Milne-Edwards 
et Haime, Recherches, etc., q. a. p. 31, note 2. 

3 Siebold, (C. Th. E, v.,) Beitrage zur Natur- 
geschichte der wirbellosen Thiere, Dantzig, 1839, 



q. a 



4to. p. 29. — Loven, (S. L.) Beitrag zur Kenntniss 
der Gattungen Campanularia und Syncoryne, Wiegm. 
Arch., 1837, p. 249 and 321 ; French Ann. Sc. n. 
2de ser., vol. 15, p. 157. — Sars, (M.,) Beskrivelser, 

Fauna littoralis, q. a. — Nordmann, (Al. v.,) 
Sur les changements que 1'age apporte dans la 

V 

■ 

maniere d'etre des Campanulaires, . Comptes-Rendus, 
1834, p. 709. — Steenstrup, (J.,) Ueber den Gene- 
rations- Wechsel oder die Fortpflanzung und Ent- 
wickelung durch abwechselnde Generationen, Uebers, 

Lorenzen, Kopenh. 1842, 8vo., fig.; Engl. 



von 



der Ver- by G. Busk, (Ray Society,) London, 1845, 8vo. 



VanBeneden, (P. J.,) Memoire sur les Campanu- 
laires de la cote d'Ostende, etc., Mem. Ac. Brux. 

1843, vol. 17, 4to. fig. — Recherches sur l'Embry- 
ogenie des Tubulaires, etc., Mem. Ac. Brux. 1844, 
4 t0- fig. — Dujardin, (Fel.,) Observations sur un 
nouveau genre de Medusaires (Cladonema,) pro- 
venant de la metamorphose des Syncorynes, Ann. Sc. 
n. 2de ser. 1843, vol. 20, p. 370. — Memoire sur le 
developpement des Medusaires et des Polypes 
Hydraires, Ann. Sc. n. 3e ser., 1845, vol. 4, p. 257. 
— Will, (J. G. Fr.,) Horse tergestinae, Leipzig, 

1844, 4to. fig. — Fret, (H.,) und Leuckart, (R.,) 
Beitrage zur Kenntniss wirbelloser Thiere, Braun- 

* 

schweig, 1847, 4to. fig. — Dalyell, (Sir J. G.,) Rare 






i 



I 






































































































I 

I 































































70 



ESSAY ON CLASSIFICATION. 



Part I 



the type of their class. Few multiply in a direct, progressive development. As to 
Echinoderms, they have for a long time almost entirely escaped the attention of 
Embryologists, but lately J. Muller has published a series of most important investi- 
gations upon this class/ disclosing a wonderful diversity in the mode of their develop- 



and Remarkable Animals of Scotland, etc., London, 
1847, 2 vols. 4to. fig. — Forbes, (Ed.,) Monograph 
of the British Naked-eyed Medusas, London, 1847, 



Schultze, (M. : ) Ueber die mannlichen Geschle- 
chtstheile der Campanularia geniculate, Miiller's 
Arch., 1850, p. 53. — Hincks, (Th.,) Notes on the 



1 vol. fol. fig. (Ray Society.) — On the Morphology Reproduction of the Campanulariaclas, etc., Ann. and 



of the Reproductive System of Sertularian Zoophytes, Mag. Nat. Hist., 2d ser., 1852, vol. 10, p. 81. 



Fur- 



., Ann. and Mag. Nat. Hist., 1844, vol. 14, p. 3 
Agassiz, (L.,) Twelve Lectures, etc., q. a. 



ther Notes on British Zoophytes, Ann. and Mag. Nat. 

Hist., 1853, vol. 15, p. 127. — Allman, (G. J.,) On 



Desor, (Ed.,) Lettre sur la generation medusipare Hydroids, Rep. Brit. Ass. Adv. Sc, 1852, p. 50. 

des Polypes Hydraires, Ann. Sc. Nat., 3e ser., 1849, Derbes, (A.,) Note sur les organes reproducteurs et 

vol. 12, p. 204. — Krohn, (A.,) Bemerkungen liber l'embryogenie du Cyanea chrysaora, Ann. Sc. Nat., 

die Geschlechtsverhaltnisse der Sertularinen, Mul- 3e ser., 1850, vol. 13, p. 377. — Vogt, (C.,) Ueber 

ler's Arch., 1843, p. 174. — Ueber die Brut des die Siphonophoren, Zeitsch. f. wiss. Zool., 1852, 

vol. 3, p. 522. — Huxley, (Th. H.,) On the Anat- 

Stauridium, Miiller's Arch., 1853, p. 420. — Ueber omy and Affinities of the Family of the Medusa, 

Podocoryne carnea Sars und die Fortpflanzungsweise Philos. Trans. Roy. Soc, 1849, II., p. 413. 



Cladonema radiatum und deren Entwickelung zum 



An 



Account of Researches into the Anatomy of the 
1851, I., p. 263. — Ueber einige niedere Thiere, Hydrostatic Acalephse, Proc. Brit. Ass. Adv. Sc, 
Miiller's Arch., 1853, p. 137. — Ueber die friihesten 1851, p. 78. — Leuckardt, (R.,) Zoologische Unter- 



ihrer medusenartigen Sprosslinge, Wiegm. Arch., 

Ueber einige niedere Thiere, 



Entwickelungsstufen der Pelagia noctiluca, Miiller's 

■ 

Arch., 1855, p. 491. — Kolliker, (A.,) Die Schwimm- 
polypen, etc., q. a. — Busch, (W.,) Beobachtungen 
liber Anatomie und Entwickelungsgeschichte einiger 
wirbelloser Seethiere, Berlin, 1851, 4to. fig. pp. 1, 
25 and 30. — Gegenbauer, Kolliker und MiJL- 
TT7T? TWiVM iiW piniVp. im Herbste 1852 in Messina 



Wiegm. Arch., 1854, p. 249. 



suchungen, Giessen, 1853-54, 4to. fig. 1st Fasc. 
Zur nahern Kenntniss der Siphonophoren von Nizza, 

Stimpson, (W.,) 
Synopsis of the Marine Invertebrata of Grand Manan, 
Smithson. Contrib., 1853, 4to. fig. — Leidy, (Jos.,) 
Contributions towards a Knowledge of the Marine 

Invertebrate Fauna, etc., Journ. Acad. Nat. Sc, 



angestellte anatomische Untersuchungen, Zeitsch. f. Philad., 2d ser. 1855, vol. 3, 4to. fig. — See also 
wiss. Zool., vol. 4, p. 299. — Gegenbauer, (C.,) below, Sect. 20. 



Ueber die Entwickelung von Doliolum, der Schei- 



Beskrivelser, etc., p. 37. — Ueber die Ent- 



benquallen und von Sagitta, Zeitsch. f. wiss. Zool., wickelung der Seesterne, Wiegm. Arch., 1844, I., 
1853, p. 13. — Beitrage zur nahern Kenntniss der p. 169, fig.— Fauna littoralis, etc., p. 47. — Muller, 



Schwimmpolypen (Siphonophoren,) Zeitsch. f. wiss. 



(J.,) Ueber die Larven u. die Metamorphose der 



Zool., 1853, vol. 5, p. 285. — Ueber Diphyes turgida, Ophiuren u. Seeigel, Akad. d. Wiss., Berlin, 1848. 



4JVJKJJ.., XVUV, VWX. ^, j^. ~W^. V^KJKSS. ^l|/x V V^ t,^^ 

etc., Zeitsch. f. wiss. Zool., 1853, vol. 5, p. 442. 



Ueber die Larven u. die Metamorphose der Echino- 



Ueber den Entwickelungscyclus von Doliolum, etc., dermen, 2te Abh., Ak. d. Wiss., Berlin, 1849. 



Zeitsch. f. wiss. Zool., 1855, vol. 7, p. 283. 



Ueber die Larven u. die Metamorphose der Holo- 



Frantzius, (Al. v.,) Ueber die Jungen der Cephea, thurien n. Asterien, Ak. d. "Wiss., Berlin, 1850. 

Zeitsch. f. wiss. Zool., vol. 4, p. 118. — Muller, (J.,) Ueber die Larven u. die Metamorphose der Echino- 

Ueber eine eigenthiimliche Meduse des Mittelmeeres dermen, 4te Abh., Ak. d. Wiss., Berlin, 1852. 

und ihren Jugendzustand, Midler's Arch., 1851, p. 272. Ueber die Ophiurenlarven des Adriatischen Meeres, 















\ 










v 







L * VF 



t 












Chap. I. 



METAMORPHOSES OF ANIMALS. 



71 



ment, not only in 



the different orders of the class, but even in different genera 



of the same family. 



The larvse of many have a close resemblance to diminutive 



Ctenophorse, and may be homologized with this type of Acalephs. 

As I shall hereafter refer frequently to the leading divisions of the animal king- 
dom, I ought to state here, that I do not adopt some of the changes which have 
been proposed lately in the limitation of the classes, and which seem to have been 
pretty generally received with favor. The undivided type of Radiata appears to 
me as one of the most natural branches of the animal kingdom, and I consider 
its subdivision into Coelenterata and Echinodermata, as an exaggeration of the ana- 
tomical differences observed between them. As far as the plan of their structure 
is concerned, they do not differ at all, and that structure is throughout homologi- 

In this branch I recognize only three classes, Polypi, Acalephw, and Echhwder- 



cal. 

mata. 
the 



The chief difference between the 



two first lies in the radiating partitions of 



mam 



digestive cavity in 
the 



cavity of the Polypi, supporting the reproductive organs; moreover, the 

this class consists of an inward fold of the upper aperture of 



common sac 



of the body, while in Acalephs there exist radiating tubes, at least 

which extend to the margin of the body where they anas- 






in the proles medusina, 

tomoze, and the digestive cavity is 

body. This is 



hollowed out of the gelatinous mass of the 



equally true of the Hydroids, the Medusae proper, and the Cteno- 
phorse ; but nothing of the kind is observed among Polypi. Siphonophorae, whether 
their proles medusina becomes free or not, and Hydroids agree in having, in the proles 
medusina, simple radiating tubes, uniting into a single circular tube around the mar- 

These two groups, constitute together, one natural 
order, in contradistinction from the Covered-eyed Medusae, whose radiating tubes 
ramify towards the margin and form a complicated net of anastomoses. Morpho- 



gin of the bell-shaped disk. 



logically, the proles polypoidea of the Acalephs, is as completely an Acaleph, as their 



Ak. d. Wiss., Berlin, 1852. — Ueber den allge- 

■ 

meinen Plan in der Entwickelung der Echinodermen, 
Ak. d. Wiss., Berlin, 1853. — Ueber die Gattungen 
der Seeigellarven, 7te Abh., Ak. d. Wiss., 1855. 



Agassiz, (L.,) Twelve Lectures, etc., p. 13. 

■ 

Dekbes, (A.,) Sur la formation de l'embryon chez 
l'oursin comestible, Ann. Sc. Nat., 3e ser., vol. 8, 



P 



80. 



(W 



P 



.400. 



Krohn, (A.,) Ueber die Entwickelung der 



Seesterne und Holothurien, Muller's Arch., 1853, 

Ueber die Entwickelung einer lebendig 



P 



317. 



Ueber den Canal in den Eiern der Holothurien, Ueber die Larve der Comatula, Muller's Arch. 1849, 
Muller's Arch., 1854, p. 60. — French abstracts of 
these papers may be found in Ann. Sc. Nat., 3e 

■ 

ser., 1852 and '53, vols. 17, 19, and 20; An English 
account is published by Huxley, (Th. H.,) Report 
upon the Researches of Prof. Miiller into the Anat- 
omy and Development of the Echinoderms, Ann. and 
Mag. Nat. Hist., 2d ser., vol. 8, 1851, p. 1. 



\ 



gebahrenden Ophiure, Muller's Arch., 1851, p. 338. 
Ueber die Larve des Echinus brevispinosus, Mul- 



ler's Arch., 1853, p. 361. 



Beobachtungen iiber 



Koren Echinodermenlarven, Muller's Arch., 1854, p. 208. 



und Danielssen in Nyt Magazin for Naturvid, vol. 5, Schultze, (M.,) Ueber die Entwickelung von Ophio- 
p. 253, Christiania, 1847 ; Ann. Sc. Nat. 1847, p. 347. lepis squamata, Muller's Arch., 1852, p. 37. 








I ! 
























! 







I 

































I, 






▼■■ 





















































































72 



ESSAY ON CLASSIFICATION 



Part I 



proles medusina, 1 and whether they separate or remain connected, their structural 
relations are everywhere the same. A comparison of Hydractinia, which is the 



most common and the most polymorphous Hydroid, with our common Portuguese 



Man-of-War (Physalia,) may at once show the homology of their most polymorphous 



individuals. 



The 



mbryology of Mollusks has been very extensively 



gated, and 



*7P 



of this branch are 



g the very best known in the animal kingdom 



some 
The 



natural limits of the branch itself appear, however, somewhat doubtful. I hold that 



it must include the Bry 



2 



which lead gradually through the Brachiopods 



3 



and 



Tunicata to the ordinary Acephala, and I would add, that I have satisfied myself 



of the propriety of 



g 



the Vorticellidse with Bry 



On the other hand, the 



distinct branch 



Cephalopods can never be separated from the Mollusks proper, as a 
the partial segmentation of their yolk no more affords a ground for their separation, 
than the total segmentation of the yolk of Mammalia would justify their separation 
from the other Vertebrata. Moreover, Cephalopods are in all the details of their 
structure homologous with the other Mollusks. The Tunicata are particularly inter- 



g, inasmuch as the simple Ascidians have pedunculated youn 



5? 



which exhibit the 



most striking resemblance to Boltenia, and form, at the same time, a connecting link 
with the compound Ascidians. 4 The development of the Lamellibranchiata seems to 



1 I shall show this fully in my second volume. 



Analecta ad Ophrydii versatilis historiam naturalem, 



Meanwhile, see my paper on the structure and Vratislav, 1849. — Lachmann, (C. F. J.,) Ueber die 



homologies of Radiata, q. a., p. 20. 



Organization der Infusorien, besonders der Vorticel- 



2 Allman, (G. J.,) On the Present State of our len, Midler's Arch., 1856, p. 340. Having satisfied 
Knowledge of the Fresh Water Polyzoa, Proc. Brit. myself that the Vorticellidae are Bryozoa, I would 

also refer here to all the works on Infusoria in which 



Asso. Adv. Sc, 20th Meet., Edinburgh, 1850, p. 305. 
Proc. Irish Ac. 1850, vol. 4, p. 470. — Ibid., 1853, 
vol. 5, p. 11. — VanBeneden, (P. J.,) Recherches 
sur l'Anatomie, la physiologie et le developpement 
des Biyozoaires qui habitent la cote d'Ostende, Nouv- 



these animals are considered. 

8 I see from, a short remark of Leuckart, Zeitsch. 
f-wiss. ZooL, vol. 7, suppl., p. 115, that he has also 
perceived the close relationship which exists between 



Mem. Ac. Brux., 1845, vol. 18.— Dumortier, (B. C.,) Brachiopods and Bryozoa. 



et VanBeneden, (P. J.,) Histoire naturelle des 

- 

Polypes composes d'eau douce, Mem. Ac. Brux., 



4 Savigny, (J. C.,) Memoires sur les Anim. sans 
Vertebres, etc. q. a. — Chamisso, (Ad. a.,) De 



1850, vol. 16, 4to. fig. — Hincks, (Th.,) Notes on animalibus quibusdam e classe Vermium Linnasana, 
British Zoophites, with Descriptions of some New Fasc. 1, De Salpa, Berol, 1819, 4to., fig. — Meyen, 

•. Nat. Hist., 2d ser., 1851, (F. J.,) Beitrage zur Zoologie, etc., 1st Abth., fiber 



Ma 



vol. 8, p. 353. — Ehrenberg, (C. G.,) Die Infu- Salpen, Nov. Act. Nat. Cur. 1832, vol. 16. 
sionsthiere als vollkommene Organismen, Leipzig, Edwards, (H. Milne,) Observations sur les Asci- 
1838, 2 vols. fol. fig. — Stein, (F.,) Infusionsthiere dies composees des cotes de la Manche, Paris, 1841, 



auf ihre Entwickelungsgeschichte untersucht, Leip- 
zig 1854, 1 vol. 4to. fig. — Frantzius, (Al. v.,) 



4to., fi 



g- 






litt., q. a. 



Sars, (M.,) Beskrivelser, q. a. — Fauna 
VanBeneden, (P. J.,) Recherches sur 



i 















■ 















Chap. I. 



METAMORPHOSES OF ANIMALS. 



1° 



O 



b 



* 

very uniform, but they differ greatly as to their breeding, many laying their 



eggs before the germ is formed, whilst 



carry them in their 



g- 



until the 



young are entirely formed 
which, however, lav their 



This is observed particularly among the Unios, some of 



« 



very early, while others carry 



them for a longer 



shorter time, in a special pouch of the outer gill, which presents the most dive 



tied forms in different 



g 



development of Brachiopods 



of this family. Nothing is as yet known of the 
The Gasteropods 2 exhibit a much greater diversity 



l'embryogenie, l'anatomie et la physiologie des Asci- 
dies simples, Mem. Ac. Brux., 1847, vol. 20. 
Krohn, (A.,) Ueber die Entwickelung der Aseidien, 
Midler's Arch., 1852, p. 312.— Kolliker, (A,) 
et Lowig, De la composition et de la structure 
des enveloppes des Tuniciers, Ann. Sc. Nat. 3e ser., 
vol. o, p. 193.— Huxley, (Th. H.,) Observations 
upon the Anatomy and Physiology of Salpa and 
Pyrosoma, Philos. Trans. R. Soc, 1851, II., p. 567. 
Eschricht, (D. F.,) Anatomisk-physiologiske 



Undersogelser over Salperne, 



Kiob. 1840, fig. 



q. a. 



Steenstrup, (J. ? ) Ueber den Generationswechsel, 

Vogt, (C.,) Bilder aus dem Thierleben, 
Frankfurt a. M., 1852, 8vo. — Muller, (H.,) Ueber 
Salpen, • Zeitsch. f., wiss., Zool., vol. 4, p. 329. 
Letjckart, (R.,) Zoologishe Untersuchungen, Gies- 
sen, 1853-54, 4to., fig., 2d Fasc. 

1 Carus, (C. G.,) Entwickelungsgeschichte unse- 
rer Flussmuschel, Leipzig, 1832, 4to., fig.— Quatre- 
fages, (Arm. de,) Sur l'embryogenie des Tarets, 



Ann. Sc. Nat., 3e ser., 1849, vol. 2, p. 202. 



Sur 



la vie interbranchiale des petites Anodontes, Ann. Sc. 
Nat., 2de ser., vol. 5, p. 321. — Loven, (S. L.,) Om 



Utvecklingen of Mollusca Acephala, Overs. 



Vet. 



Akad. Forhandi. Stockholm, 1849. 



Germ. Muller's 



Arch., 1848, p. 531, and Wiegman's Arch., 1849, 
p. 312. — Prevost, (J. L.,) De la generation chez la 
moule des peintres, Mem. Soc. Phys. Geneve, 1825, 
vol. 3, p. 121. — Schmidt, (0.,) Ueber die Entwicke- 

calyculata Drap. Muller's Arch., 
1854, p. 428. — Leydig, (F.,) Ueber Cyclas cornea, 
Muller's Arch., 1855, p. 47. 



lung von Cyclas 



Geneve, vol. 5, p. 119. — Sars, (M.,) Zur Entwicke- 
lungsgeschichte der Mollusken und Zoophyten, 
Wiegm. Arch., 1837, I., p. 402; 1840, I., p. 196. 
Zusatze zu der von mir gegebenen Dartstellung 
der Entwickelung der Nudibranchien. Wiegm. Arch. 

1845, 1. p. 4. — Quatrefages, (Arm. de,) Memoire 

■ 

sur l'Embryogenie des Planorbes et des Lymnees, 
Ann. Sc. Nat., 2de ser., vol. 2, p. 107. — VanBene- 
den, (P. J.,) Recherches sur le developpement des 
Aplysies, Ann. Sc. Nat., 2de ser., vol. 15, p. 123. 
VanBeneden, (P. J.,) et Windischman, (Ch.,) 

Recherches sur l'Embryogenie des Limaces, Mem. 

Ac. Brux., 1841. — Jacquemin, (Em.,) Sur le 
developpement des Planorbes, Ann. Sc. Nat., vol. 5, 
p. 117; Nov. Act. Nat. Cur., vol. 18. — Dumor- 
tier, (B. C.,) Memoire sur les evolutions de 
l'embryon dans les Mollusques Gasteropodes, Mem. 

Ac. Brux., 1836, vol. 10. — Laurent, (J. L. M.,) 
Observations sur le developpement de l'oeuf des 
Limaces, Ann. Sc. Nat., vol. 4, p. 248. — Pouchet, 
(F. A.,) Sur le developpement de l'embryon des 
Lymnees, Ann. Sc. Nat., 2de ser., vol. 10, p. 63. 
Vogt, (C.,) Recherches sur l'Embryologie de l'Ac- 
ta3on, Ann. Sc. Nat., 3e ser., 1846, vol. 6, p. 5. 
Beitrag zur Entwickelungsgeschichte eines Cepha- 
lophoren, Zeitsch. f. wiss. Zool., 1855, vol. 7, p. 162. 
Schultze, (M.,) Ueber die Entwickelung des 
Tergipes lacinulatus, Wiegm. Arch., 1849, I., p. 268. 
Warneck, (N. A.,) Ueber die Bildung und 
Entwickelung des Embryo bei Gasteropoden, Bull. 
Soc. Imp., Moscou, 1850, vol. 23, I., p. 90. 

■ 

Schmidt, (O.,) Ueber die Entwickelung von Limax 



> 



2 Carus, (C. G.,) Von den aussern Lebensbe- agrestis, Muller's Arch., 1851, p. 278.— Leydig, 



dingungen der weiss- und kaltblutigen Thiere, Leip- (F.,) Ueber Paludina vivipara 



ein Beitrag zur 



zig, 



1824, 4to., fig. 



Pkevost, (J. L.,) De la nahern Kenntniss dieses Thieres in embryologischer, 





generation chez le Lymnee, Mem. Soc. Phys., 

10 



anatomischer und histologischer Beziehung, Zeitsch. 
























1 



1 
















if 














































































74 



ESSAY ON CLASSIFICATION. 



Part I. 



there are striking differences. 



in their development than the Lamellibranchiata 

aqnatic Puhnonata 

remarkable for the curious cases in which their 

developed, to an advanced state of growth. The cases of Pyrula and Strombus 



Even among the terrestrial and 
Some of the Pectinibranchiata are 
eggs are hatched and the youno* 



o 



among the most extraordinary of these org 



nests. The embryology of Cepha- 



lopods 



has b 



masterly illustrated by Kolliker 



There is still much diversity of opinion among naturalists 



pecting the limits 



of Articulata: some being inclined to separate the Arthropoda and Worms as di 



f. wiss. Zool., 1850, vol. 2, p. 125. — Kolliker, Phils. Trans. R. Soc, 1853, I., p, 29. — Hogg, 

(A.,) q. a., Zeitsch. f. wiss. Zool., vol. 4, p. 333 and ,(Jabez,) On the Development and Growth of the 

369. — Muller, (J.,) Ueber verschiedene Formen "Watersnail, Quart. Micr. Journ., 1854, p. 91. — Reid, 

von Seethieren, Muller's Arch., 1854, p. 69. — Ueber (J.,) On the Development of the Ova of the Nudi- 
Synapta digitata und iiber die Erzeugung von 
Schnecken in Holothurien, Berlin, 1852, 4to. fig. 



branchiate Mollusca, Ann. and Mag. Nat. Hist., 1846, 

vol. 17, p. 377. — Carpenter, (W. B.,) On the 
The remarkable case described in this paper, admits Development of the Embryo of Purpura Lapillus, 
of an explanation which Muller has not considered. Quart. Micr. Journ., 1845, p. 17. 



It is known, that fishes penetrate into the cavity of 
the body of Holothuria3, through its posterior open- 
ing. (De Bosset, Notice, etc., Mem. Soc. Sc. Nat, 
Neuch., 1839, vol. 2, 4to.) The similarity of Ento- 
concha mirabilis with the embryonic shell of various 

■ 

species of Littorinae, such as Lacuna vincta, the 



1 Kolliker, (Alb.,) Entwickelungsgeschichte 



der Cephalopoden, Zurich, 1844, 4to., fig. 



VAN- 



IS ENEDEN, (P. J.,) Recherches sur l'Embryogenie 
des Sepioles, N. Mem. Acad. Brux., vol. 14, 1841. 



(Z 



Ma 



Duges, (Ant.,) 



development of which I had an opportunity of study- Sur le developpement de l'embryon chez les Mollus- 

ing, suggests the possibility, that some species of this ques Cephalopodes, Ann. Sc. Nat., vol. 8, p. 107. 

family, of which there are many very small ones, Rathke, (H.,) Perothis, ein neues genus der Cepha- 

select the Synapta as their breeding place and leave lopoden, Mem. Ac. St. Petersb., 1834, vol. 2, p. 

it after depositing their eggs, which may become con- 149. (Is the young of some Loligoid Cephalopod.) 



nected w T ith the 



Mistletoe 



Milne-Edwards, (H.,) Observations sur les sper- 



Orobanche and many other parasitic plants, with the matophores des Mollusques Cephalopodes, etc., Ann. 
plants upon which they grow. — Gegenbauer, (C.,) Sc, n., 2de ser., vol. 3, p. 193. — Kolliker, (A.,) 
Beitrage zur Entwickelungsgeschichte der Landgas- • Hectocotylus Argonauts Delle Chiaje und Hect. 
teropoden, Zeitsch. f. wiss. Zool., 1852, vol. 3, p. 371. 
Untersuchungen iiber Pteropoden und Heteropoden, 
Leipzig, 1855, 1 vol., 4to. fig. — Koren, (J.,) und 



Tremoctopodis K., die Mannchen von Argonauta 
Argo und Tremoctopus violaceus, Ber. Zool. Anst. 
Wurzburg, 



1849, p. 69. — Muller, (H.,) Ueber 
Danielssen, (D. C.,) Bitrag til Pectinibranchiernes das Mannchen von Argonauta Argo und die Hecto- 
Udviklingshistorie, Bergen, 1851, 8vo. ; French Ann. eotylen, Zeitsch. £ wiss. Zool., vol. 4, p. 1. — Vera- 
Sc. Nat., 1852, vol. 18, p. 257, and 1853, vol. 19, NY, (J. B.,) et Vogt, (C.,) Memoire sur les Hec- 



p. 89 ; also Germ, in Wiegm. Arch., 1853, p. 173. 



tocotyles et les males de quelques Cephalopodes, 



Nordmann, (Al. V.,) Versuch einer Monographic Ann. Sc. n., 3e ser., 1852, vol. 17, p. 147. — Rou- 

von Tergipes Edwardsii, St. Petersburg, 1844, 4to.— lin, (F. D.,) De la connaissance qu'ont eue les 

Leuckart, (R.,) Zoologische Untersuchungen, Gies- anciens du bras copulateur chez certains Cephalo- 

sen, 1853-54, 4to., fig., 3d Fasc. — Huxley, (Th. H.,) podes, Ann. Sc. n., 3e ser., 1852, vol. 17, p. 188. 

■ 

On the Morphology of the Cephalous Mollusca, etc., Leuckart, (R.,) Zool. Unters. q. a. 































Chap. I. 



METAMORPHOSES OF ANIMALS. 



75 



tinct branches, while others unite 
for a distinction. The worm-like 



them 



of the 



one. I confess I cannot see the ground 
larvae of the majority of Arthropods 



and the perfect homology of these larvae with the true Worms, seem to me to 
show beyond the possibility of a doubt, that all these animals are built upon one 



and the same 




and belong, therefore 



one 



branch, which 



classes, if the principles laid down in my second chapt 



are 



all correct, namely 



the Worms, Crustacea, and Insects 



As to the Protozoa, I have little confidence 



in the views generally entertained respecting 



their nature. Having satisfied myself 



the brood of Planariae, and Opalina that of Dis- 

3 division 

i develop- 



that Colpoda and Paramecium are 

toma, I see no reason, why the other Infusoria, included in Ehrenberg 

Enterodela, 1 should not also be the brood of the many lower Worms, th« 



Again, a comparison of the early 

to show. 



ment of which has thus far escaped our attention. 

stages of development of the Entomostraca with Rotifera might be sufficient 
what Burmeister, Dana, and Leydig have proved in another way, that Rotifera are 
inuine Crustacea, and not Worms. The vegetable character of most of the Anen- 



g 



tera has been satisfactorily 



ated. I have not yet been able to arrive at 



definite result respecting the Rhizopods, thoug 



they may represent 



the typ 



a 
of 



Mollusks, the stage of yolk segmentation 

should be inferred, that I do not consider the Protozoa 

animal kingdom, nor the Infusoria as a natural class 



of Gasteropods. From these remarks it 



distinct branch of the 



Taking the class of Worms, in the 



widest sense, it would thus embrace the 



■ 
















{ 






1 
I 






i 



/ 






That Vorticellidae are Bryozoa, has already 



Zoo- 



been stated above. 

2 Schultze, (M.,) Beitrage zur Naturge 
den Turbellarien, Greifswald, 1851, 4to., fig. 
logische Skizzen, Zeitsch. f. wiss. Zool. 1852, vol. 4, 
p. 178. — Muller, (J.,) Ueber eine eigenthiimliche 
Wurmlarve, etc., Archiv, 1850, p. 485.— Desor, 
(E.,) On the Embryology of Nemertes, with an Ap- 
pendix on the Embryonic Development of Polynoe, 
Boston Journ. Nat, Hist. 1850, vol. 6, p. 1 ; Miiller's 
Archiv, 1848, p. 511. — Agassiz, (L.,) Colpoda and 
Paramecium are larvas of Planari^e, Proc. Am. Ass. 
Adv. Sc, Cambridge, 1849, p. 439. — Girard, (Ch.,) 
Embryonic Development of Planocera elliptica, Jour. 
Ac. Nat. Sc. Phil., 2d ser. 1854, vol. 2, p. 307. 
Ehrenberg, (C. G.,) Die Infusionsthierchen, etc., 
q. a. 



einzellige Pflanzen und Thiere, Zeitsch. f. wiss. Zool. 
1849, vol. 1, p. 270. — Naegeli, (C.,) Gattun 



gen 



einzelliger Algen, Zurich, 1849, 4to. fig. — Bratjn, 
(A.,) Algarum unicellularium genera nova et minus 
cognita, Leipzig, 1855, 4to. %. — Cohn, (F.,) Bei- 

Entwickelungsgeschichte der Infusorien 
Zeitsch. f. wiss. Zool. 1851, vol. 3, p. 257. 



trage zur 



Bei- 



1SS. 



trage zur Kenntniss der Infusorien, Zeitsch. f. w 
Zool. 1854, vol. 5, p. 420. — Ueber Encjstirung von 
Amphileptus fasciola, ibid. p. 434. — Schultze, (M.,) 
Ueber den Organismus der Polythalamien, Leipzig, 
1854, 1 vol. fol. fig. — Beobachtungen iiber die Fort- 



Muller 



i 



p 



165. 



Aiterbach, (L.,) Ueber die Einzelligkeit 
der Amoeben Zeitsch. f. wiss. Zool. 1855, vol. 7, 

Ueber Encystirung von Oxytricha Pellio- 



P 



. 365. 



# 

Kutzing, (F. T.,) Ueber die Verwandlung nella, Zeitsch. f. wiss. Zool. 1854, vol. 5, p. 430, 
der Infusorien in niedere Algenformen, Nordhausen, Cienkowsky, Ueber Cystenbildung bei Infusorien, 



4to. fig, 



Siebold, (C. Th. E. v.,) Ueber 

» 



Zeitsch. f. wiss. Zool. 1855, vol. 6, p. 301. 







i 



II 
















\ 






•S? 













































76 



ESSAY ON CLASSIFICATION 



Part I 



* 

Helminths, Turbellariae, and Annulata. The embryology of these animals still requires 



careful 



study, notwithstanding the many extensive investigations to which they have 



been submitted; the intestinal "Worms especially continue to baffle the zeal of 
naturalists, even now when the leading features of their development are ascertained. 
The Nematoids undergo a very simple development, without alternate generations, 
and as some are viviparous their changes can easily be traced. 1 The Cestods and 
Cystici, which were long considered as separate orders of Helminths, are now known 

4 

another, the Cystici being only 
The Trematods exhibit the most 



direct genetic connection with 



one 



to stand in 

earlier stages of development of the Cestods. 2 

complicated phenomena of alternate generations ; but as no single species has thus 

far been traced through all the successive stages of its transformations, doubts are 












































1 Stein, (F.,) Beitrage zur 



Entwickelungsges- 



Bestatigung des von Dr. Newport bei den Batra- 
cliichte der Eingeweidewurmer, Zeitsch. f. wiss. Zool., cliiern und Dr. Barry bei den Kaninchen behaupte- 
1852, vol. 4, p. 196. — Nelson, (H.,) On the Re- ten Eindringens der Spermatozoiden in das Ei, Gies- 
production of the Ascaris Mystax, Philos. Trans. sen, 1854, 4to. 

2 Van Beneden, (P. J.,) Les Helminthes Ces- 

toides, etc., Bullet. Ac. Belg., vol. 16, et seq.; Mem. 



R. Soc, 1852, II., p. 563. — Grube, (E.,) Ueber 

Entwickeluns: von Gor- 



einige Anguillulen und die 



dius aquaticus, Wiegmann's Archiv, 1849, I., p. 358. Ac. Brux., 1850, vol. 17, et seq. — Kolliker, (A.,) 



Siebold, (C. Th. E. v.,) Ueber die Wanderung 



Beitrage, etc., q. a. ; p. 81. — Siebold, (C. Th. E. 



der Gordiaceen, Uebers. d. Arb. und Ver. schles. v.,) Ueber den Generationswechsel der Cestoden, etc., 



Ges. f. vaterl. Kultur., 1850, p. 38. — Meissner, 
(G.,) Beitrage zur Anatomie und Physiologie von 
Mermis albicans, Zeitsch. f. wiss. Zool., 1853, vol. 5, 



P 



207. 



Beobachtungen uber das Eindringen der 



Zeitsch. wiss. Zool., 1850, vol. 2, p. 198. — Ueber 
die Umwandlung von Blasenwiirmer in Bandwiirmer, 
Uebers. d. Arb. und Ver. d. schles. Ges. f. vaterl. 
Kultur, 1852, p. 48. 



Ueber die Verwandlung des 



Saamenelemente in den Dotter, Zeitsch. f. wiss. Cysticercus pisiformis in Taenia serrata, Zeitsch. f. 

Zool., 1855, vol. 6, p. 208, und 272. — Beitrage zur wiss. Zool., 1853, vol. 4, p. 400. — Ueber die Ver- 



Anatomie und Physiologie der Gordiaceen, Zeitsch. f. 
wiss. Zool., 1855, vol. 7, p. 1. — Kolliker, (A.,) 
Beitrage zur Entwickelungsgeschichte wirbelloser 
Thiere, Miiller's Archiv, 1843, p. 68. — Bagge, 
(H.,) Dissertatio inaug. de evolutione Strongyli au- 
ricularis et Ascaridis acuminata^, Erlangen, 1841, 
4to. fig. — Leidy, (Jos.,) A Flora and Fauna within 
living Animals, Smithson. Contrib. 1853, 4to. fig. 



wandlung der Echinococcus-Brut in Tsenien, Ibid., 
1853, p. 409. — Ueber die Band-und Blasenwiirmer, 
nebst einer Einleitung uber die Entstehung der Ein- 

« 

geweidewurmer, Leipzig, 1854, 8vo. fig. — Huxley, 
(Th. H.,) On the Anatomy and Development of 
Echinococcus veterinorum, Ann. and Ma£. Nat. Hist. 
2d ser., vol. 14, p. 379. — Kuchenmeister, (Fr.,) 
Ueber die Umwandlung der Finnen (Cysticerci) in 
Luschka, (H.,) Zur Naturgeschiclite der Trichina Bandwiirmer (Taeniae) Prag. Vierteljahrssch, 1852, 



spiralis, Zeitsch. f. wiss. Zool. 1851, vol. 3, p. 69. 



p. 106. — Wagener, (R. G.,) Die Entwickelung der 



Bischopf, (Th.,) Ueber Ei- und Samenbildung und Cestoden, Bonn, 1855, 1 vol. 4to. fig. — Meissner, 



(G.,) 



Zur Entwickelungsgeschichte und 



Anatomie 



der Bandwiirmer, Zeitsch. f. wiss. Zool., 1854, voL 



Befruchtung bei Ascaris Mystax, Zeitsch. f. wiss. 

Zool., 1855, vol. 6, p. 377. — Widerle 

Dr. Keber bei den Najaden und Dr. Nelson bei 5, p. 380. — Leuckart, (R.,) Erziehung des Cysti- 

den Ascariden behaupteten Eindringens der Sper- cercus fasciolaris aus den Eiern der Tamia crassi- 

matozoiden in das 



Ei, Giessen, 1854, 4to. fig. 



collis, Zeitsch. f. wiss. Zool. 1854, vol. 6, p. 139. 












^ 




















\ 



Chap. I. 



METAMORPHOSES OF ANIMALS. 



77 



still entertained respecting the genetic connection of many of the forms which 
appear to belono- to the same organic cycle. 1 It is also still questionable, whether 



Gregarinse and Psorospermia are embryonic forms or not, though the most recent 

that they are. 2 The development of the Annu- 



investigations render it probable 



lata, 



as 



they 



are now 



the Nematods, in 



circumscribed, exhibits great variety ; 6 some resemble more 
their metamorphoses, while others, the Leeches for instance, 












1 Nokdmann, (Al. v.,) Micrographische Beitrage 
zur Naturgeschichte der wirbellosen Thiere, Berlin, 
1832, 4to. fig.— Bo janus, (L.,) Zerkarien und ihr 



Fundort, Isis 1818, vol. 4, p. 729. 



Enthelmin- 



tica Isis 1821, p. 162.— Carits, Beobaclitungen iiber 
einen merkwiirdigen Eingeweidewurm, Leucochlon- 
dium paradoxum, Nov. Act. Ac. Nat. Cur., vol. 17, 
p. 85. — Siebold, (C. Th. E. v.,) Helminthologische 
Beitrage, Wiegman's Archiv, 1835, vol. 1, p. 45. 
Ueber die Conjugation des Diplozoon paradoxum, 
etc., Zeitsch. f. wiss., Zool., 1851, vol. 3, p. 62. 
Gyrodactylus, ein ammendes Wesen. Zeitsch. f. wiss. 
Zool., 1849, vol. 1, p. 347. — Steenstrup, (J.,) Ge- 
nerationswechsel, etc., q. a. — Bilharz, (Th.,) Em 
Beitrag zur Helminthographia humana, Zeitsch. f. 
wiss. Zool., 1852, vol. 4, p. 59. — Agassiz, (L.,) Zoo- 
logical Notes, etc., Amer. Journ. Sc. and A. 1852, vol. 



13, p. 425. — Baer, (K. E. v.,) Beitrage zur Kennt- 
niss der niedern Thiere, Act. Nov. Nat. Cur. 1827, 

■ 

vol. 13. — Aubert, (H.,) Ueber das Wassergefass- 
system, die Geschlechtsverhaltnisse, die Eibildung 
und die Entwickelung von Aspidogaster conchicola, 
Zeitsch. f. wiss. Zool. 1855, vol. 6, p. 349. — Leidy, 
(Jos.,) Description of two new Species of Distoma, 
with the partial History of one of them, Jour. Ac. 
Nat. Sc. Phil. 1850, vol. 1, p. 301, fig. 
2 Muller, (J.,) Ueber eine 



eigenthiimliche 

krankhafte parasitische Bildung, etc., Muller s 
Archiv, 1841, p. 477. — Ueber parasitische Bildun- 
gen etc., Midler's Archiv, 1842, p. 193.— Dufottr, 
(L.,) Note sur la Gregarine, etc., Ann. Sc. Nat., 

Ibid., 2de ser., 1837, 



1828, vol. 13, p. 366, fig. 

vol. 7, p. IO.-Siebold, (C. Th. E. v.,) Beitrage 



and p. 97. — Beitrage zur Kenntniss niederer Thiere, 
Zeitsch. f. wiss. Zool. 1848, vol. i. p. 1. — Henle, 
(J.,) Ueber die Gattung Gregarina, Miiller's Archiv, 
1845, p. 369. — Frantzius, (Al. v.,) Observations 

quaedam de Gregarinis, Berolini, 1846. — Stein, (F.,) 
Ueber die Natur der Gregarinen, Miiller's Archiv, 






1848, p 



182, fig. 



Bruch, (C.,) Einige Bemer- 



kuno-en iiber die Gregarinen, Zeitsch. f. wiss. Zool. 
1850, vol. 2, p. 110. — Leydig, (F.,) Ueber Proro- 
spermien und Gregarinen, Miiller's Archiv, 1851, 



p. 221. 



Leidy, (Jos.,) On the Organization of the 



Genus Gregarina, Trans. Amer. Phil. Soc. 1851, vol. 
10 p. 233. — Some Observations on Nematoidea im- 
perfecta and Descriptions of three parasitic Infusoria, 
Trans. Amer. Phil. Soc. 1851, vol. 10, p. 241. 
Lieberkuhn, (N.,) Ueber die Psorospermien, Miil- 
ler's Archiv, 1854, p. 1. 

8 Weber, (E. H.,) Ueber die Entwickelung von 
Hirudo medicinalis, Meckel's Archiv, 1828, p. 366, 

Filippi, (Fil.de,) Sopra l'anatomia e lo svi- 
luppo delle Clepsine, Pavia, 1839, 8vo. fig. — Loven, 
(J.,) Beobachtungen iiber die Metamorphose 



fig. 



emer 



K. Vet. Ac. Handl. 1840, Wieg 



Annelide, 

Archiv, 1842, vol. i., p. 302. — Oersted, (A. S.,) 
Ueber die Entwickelung der Jungen bei einer Anne- 
lide etc., Wiegmann's Archiv, 1845, vol. i., p. 20. 
Sars, (M.,) Zur Entwickelung der Anneliden, Wieg- 
mann's Archiv, 1845, vol. i., p. 11. — Menge, (A.,) 
Zur Eoth-Wiirmer Gattung Euaxes, Wiegmann's 
Archiv, 1845, vol. i., p. 24. — Grube, (A. E.,) Zur 
Anatomie und Entwickelung der Kiemenwiirmer, 
Konigsberg, 1838, 4to. — Actinien, Echinodermen und 
Wiirmer, etc., Konigsberg, 1840, 4to. fig. — Unter- 



etc, q. a. ; p 



56-71. 



Helminthologische Beitrage, Isis 1838, p 



Hammerschmidt, (C. Ed.,) suchungen iiber die Entwickelung der Clepsine, Dor- 
pat, 1844. — Edwards, (H. Milne,) Observations 



351. 



Kolliker, (A.,) Die Lehre von 



der thierischen sur le developpement des Annelides, Ann. Sc. Nat. 



Zelle, etc., Zeitsch. wiss. Botanik. 1845, vol. i., p. 46, 



3e ser. 1845, vol. 3, p. 145. — Koch, (H.,) Einige 
















j 









• 





















































I 





































































































78 



ESSAY ON CLASSIFICATION 



Part I 



■ 

approximate more the type of the Trematods. The Sipunculoids appear to be more 
closely related to the Annulate than to the Holothurioids. 1 



The class of Crustace 



a, on the contrary, may be considered 



as 



one of the best 



known, as far as its zoological characters and embryonic growth are concerned; the 

■ 

only point still questioned being the relationship of the Rotifera. 2 In their mode 
of development the Lernseans, the Entomostraca proper, and the Cirripeds agree as 

■ 

closely with one another as they differ from the higher Crustacea. 



This 



con- 



formity 3 is the more interesting, as the low position the Entomostraca hold in the 



Worte zur Entwickelungsgeschichte der Eunice, mit 
einem Nachworte von Kolliker, N. Denksch. Schw. 

GeselL, 1847, vol. 8, 4to. fig. — Quatrefages, (A. 

de,) Memoire sur l'Embryogenie des Annelides, Ann. 



wandte Wurmlarve, Muller's Archiv, 1850, p. 439. 
Krohn, (A.,) Ueber die Larve des Sipunculus 

nudus, etc., Muller's Archiv, 1851, p. 368. 

Schmarda, (L.,) Zur Naturgeschichte der Adria 
Sc. Nat. 3e ser., 1848, vol. 10, p. 153, fig. — Desor, (Bonellia viridis) Denksch. Wien. Akad. 1852, vol. 

4, p. 117, fig. — Gegenbauer, (C.,) Ueber die Ent- 

wickelung von Doliolum, der Scheibenquallen und 
abranchia, Journ. Ac. Nat. Sc. Phil. 1850, vol. 2, von Sagitta, Zeitsch. f. wiss. Zool. vol. 5, p. 13. 



(Ed.,) On the Embryology, etc., q. a. — Leidy, 
(Jos.,) Descriptions of some American Annelida 



p. 43, fig., (Lumbricillus contained several thousand 
large Leucophrys. The case related here by Leidy 



2 Ehrenberg, (C. J.,) Die Infusionsthierchen, 
etc., q. a. — Dalrymple, (J..) Description of an In- 



seems to me to indicate rather the hatching of Opali- fusory Animalcule allied to the Genus Notommata. 
nas from the eggs of Lumbricillus, than the presence Philos. Trans. 1844, II., p. 331. — Naegeli, (H.,) 
of parasitic Leucophrys.) — Schultze, (M.,) Ueber 



Beitrage zur Entwickelungsgeschichte der Rader- 



die Fortpflanzung durch Theilung bei Nais probosci- thiere, inaug. Diss., Zurich, 1852, 8vo. fig. — Leydig, 



Zoologische Skizzen (Arenicola piscat.) 



dea, Wiegman's Archiv, 1849, L, p. 293; id. 1852, 

I., p. 3. 

Zeitsch. f. wiss. Zool. 1852, vol. 4, p. 192. — Busch, 
(W.,) Beob. liber Anat. und Entw. q. a. (p. 55.) 
Muller, (M.,) Observationes anatomicse de Vermi- 



(Fr.,) Ueber den Bau und die systematische Stel- 
lung der Raderthiere, Zeitsch. f. wiss. Zool. 1854, 
vol. 6, p. 1. — Zur Anatomie und Entwickelungsges- 

* 

chichte der Lacinularia socialis, Zeitsch. f. wiss. Zool. 
1852, vol. 3, p. 452. — Cohn, (F.,) Ueber die Fort- 



bus quibusdam maritimis, Berolini, 1852, 4to.; Mill- pflanzung der Raderthiere, Zeitsch. f. wiss. Zool., 



ler's Archiv, 1852, p. 323. — Ueber die weitere 
Entwickelung von Mesotrocha sexoculata, Muller's 
Archiv, 1855, p. 1.— Ueber Sacconereis helgolandica, 



1855, vol. 7, p. 431. — Huxley, (Th. H.,) Lacinula- 
ria socialis, Trans. M. Soc, Micr. Journ. 1852, p. 12. 
Williamson, (W. C.,) On the Anatomy of Meli- 



Muller's Archiv, 1855, p. 13. — Krohn, (A.,) Ueber certa ringens. Quart. Micr. Journ. 1852, p. 1. 



die Ercheinungen bei der Fortpflanzung von Syllis, 

Ueber die 



Wiegman's Archiv, 1852, I., 



P 



66. 



8 Jurine, (L.,) Histoire des Monocles qui se 
trouvent aux environs de Geneve, Paris, 1806, 4to. 
Sprosslinge von Autolytus prolifer Gr., Muller's Ar- fig. — Edwards, (EL Milne,) in Cuvier, Regn. An. 
chiv, 1855, p. 489. — Leuckart, (R.,) Ueber die edit, illustr. q. a. Crustaces; represents young Li- 



ungeschlechtliche Vermehrung bei Nais proboscidea, 

Ueber die Ju- 



mulus. 



Wie 



Zaddach, (E. G.,) De Apodis cancrifor- 
mis Anatome et Historia evolutionis Bonna3, 1841, 
gendzustande einiger Anneliden, Wiegman's Archiv, 4to. fig. — Nordmann, (Al. v.,) Microgr. Beitr. q. 

Leydig, (Fr.,) Ueber Argulus foliaceus, ein 



1855, 1., p- 63. 



a. 



- 

1 Peters, (W.) Ueber die Fortpflanzungsorgane Beitrag zur Anatomie, Histologic und Entwickelungs- 



des Sipunculus, Muller's Archiv, 1850, p. 382. 



geschichte dieses Thieres, Zeitsch. f. wiss. Zool. 1850, 



- 

Muller, (M.,) Ueber eine den Sipunculiden ver- vol. 2, p. 323. — Ueber Artemia salina und Branchi- 












H»»«it * iM> *»^— 













Chap. I. 



METAMORPHOSES OF ANIMALS. 



79 






class of Crustacea, agrees strikingly with their early appearance in geological times, 
while the form of the adult Cirripeds 1 and that of the Lernaeans would hardly 



relationship, which has, indeed, been quite overlooked 

In the 



lead one to suspect their near 

until Embryology showed that their true position is among Crustacea. 

development of the higher Crustacea, 2 their superior rank is plainly exhibited, and 



few typ 



show more directly a resemblance, in their early 



« 



of development 



to the lower memb 



of their class, than the Brachy 






In the class of Insects, I include Myriapods, Arachnoids, and the true Insects, 

essed hereafter, these natural groups constitute only 



as, according to the views expr 

different degrees of complication 

must, therefore, be considered as 

class, though very extensively studied in a 5 

and as far as the habits of its representativ 



of the same combination of org 



ystems, and 



natural orders of one and the same class 



This 



much patient work, as the 




embry 



much less studied than their later transformations 



oological and anatomical point of view, 
!S are concerned, still requires, however, 
development of these animals has been 

J The type of the Arachnoids 



pus stagnalis, Zeitsch. f. wiss. Zool. 1851, vol. o, p. 

— VanBeneden, (P. J.,) Recherches sur quel- 



280. ■ 

ques Crustaces inferieurs Ann. Sc. Nat 3e ser. 18ol, 
vol. 16, p. 71. — Memoire sur le developpement et 
l'organisation des Nicothoes, Ann. Sc. Nat. 3e ser. 
1850, vol. 13, p. 354. — Barrande, (J,,) Syst. sil. q. 
a. ; contains the first observations upon the transfor- 
mations of Trilobites. 

1 Thompson, (W. V.,) 



Zoological Researches 



and Illustrations, or Natural History of nondescript 
or imperfectly known Animals, Cork, 1828-34, 8vo., 



fig. 



BURMEISTEB, (H.,) 



Beitrage zur Naturge- 



schichte der Rankenfusser, (Cirripedia,) Berlin, 1834, 
1 vol. 4to. fig.— Go.odsir, (H. D. S.,) On the Sexes, 
Organs of Reproduction, and Development of Cirri- 



fig. 



peds, Ed. N. Phil. J. 1843, No. 35, p. 88, 
Martin St. Ange, (G. J.,) Memoire sur l'organisa- 

tion des Cirripedes et sur leurs rapports naturels 
avec les animaux articules, Ann. Sc. Nat. lool, 

p. 366, fig. — Darwin, (Ch.,) A Monograph of the 
sub-class Cirripedia, with Figures of all the Species, 
London, 1851, 2 vols. 8vo. (Ray Society.) — Bate, 
(Spence,) On the Development of the Cirripedia, 
Ann. and Mag. Nat. Hist. 2d ser. vol. 8, p. 324. 

2 Rathke, (H.,) Untersuchungen iiber die Bil- 
dung und Entwickelung des Flusskrebses, Leipzig, 



1829, 1 vol. foL fig. 



Beitrage zur Fauna Norve- 
gica, Act. Nov. Ac. Leop. Cses. vol. 20. — Beitrage 
zur veroleichenden Anatomie und Physiologie, Rei- 
sebemerkungen aus Skandinavien, Dantzig, 1842, 



4to. 



Zur Morphologie, Eeisebemerkungen aus Tau- 
rien, Riga und Leipzig, 1837, 4to. fig. — Ueber die 
Entwickelung der Decapoden, Miiller's Archiv, 1836, 



P 



187, Wiegman's Archiv, 1840, I., p. 241. 



■ 



Beobachtungen und Betrachtungen iiber die Entwi- 
ekelung der My sis vulgaris, Wiegman's Archiv, 1839, 
p. 195, fig. — Erdl, (M. P.,) Entwickelung des 
Hummereies, Miinchen, 1843, 4to. fig. — Edwards, 

) sur la generation des Crustaces, Ann. 



Milne 



Sc. Nat 1829. — Observations sur les changements 
de forme que divers Crustaces eprouvent dans le 
jeune age, Ann. Sc. Nat. 2de ser. vol. 3, p. 321. 

Agassiz, (L.,) Zoological Notes, etc., Am. Jour. 
Sc. and A., 1852, p. 426. — Recent Researches, etc., 
Am. Journ. Sc. and A., 1852, vol. 16, p. 136. 

8 Herold, (M.,) Entwickelungsgeschichte der 



Schmetterlinge, etc., Kassel und Marburg, 1815, 4to. 

Disquisitiones de animalium vertebris caren- 



fig. 



fig. 



tium in ovo formatione, Frankfurt a. M., 1835, fol. 

Rathke, (H.,) Entwickelungsgeschichte der 
Blatta germanica, Meckel's Archiv, 1832. — Zur 

* 

Entwickelungsgeschichte der Maulwurfsgrille (Gryl- 
























* 










I 

■ 



i 



■■ 

























• ^"^B 


























^ 


























































! 


























80 



ESSAY ON CLASSIFICATION 



Part I 



embraces two groups, the Acari and the Arachnoids proper, corresponding respec- 
tively in this class to the Entomostraca and the higher Crustacea. The embryo 

* 

of the Acari resembles somewhat that of the Entomostraca, whilst that of the true 
Spiders 2 recalls the metamorphosis of the higher Crustacea. On the ground of the 
similarity of their young, some animals, formerly referred to the class of Worms, 2 

are now considered as Arachnoids; but the limits between the aquatic Mites and 
the Pycnogonums are not yet quite defined. 

In the branch of Vertebrata, all classes have been extensively studied, and as 
far as the principal types are concerned, the leading features of their development 
are satisfactorily known. Much, however, remains to be done to ascertain the minor 

* 

modifications characteristic of the different families. It may even be, that further 
investigations will greatly modify the general classification of the whole branch. 
The class of Fishes 3 may require subdivision, since the development of the Plagios- 



lotalpa vulgaris,) Midler's Archiv, 1844, p. 27. 
Kollikee, (A.,) Observationes de prima Insecto- 
rum Genesi, Turici, 1842, 4to. fig. — Zaddach, (G.,) 
Die Entwickelung des Phryganiden Eies, Berlin, 



(M 



ovo, Marburgi, 



1824, fol. fig. 



Rathke, (H.,) 

Ueber die Entwickelung des Scorpions; Zur Mor- 
phologie, q. a. — VanBeneden, (P. J.,) Recherches 



1 vol. 4to. 1854. — Leuckardt, (R.,) Ueber die sur 1'Histoire naturelle et le developpement de l'Atax 

Micropyle und den feinern Bau der Schalenhaut bei ypsilophora, M£m. Ac. Brux., 1850, vol. 24, p. 444. 

den Insekteneiern, Midler's Arch., 1855, p. 90. — — Wittich, (W. Hi v.,) Observationes quaedam de 

Newport, (Geo.,) On the Organs of Reproduction 

and the Development of Myriapoda, Phil. Trans. R. 

Soc, 1842, II. p. 99. — Stein, (Fr*,) Vergeichende im Eierstock, Miiller's Arch-, 1849, p. 113. — Carus, 



aranearum ex 



ovo evolutione, Diss, inaug. Halis 



Sax., 1845. — Die Entstehung des Arachnideneies 



Anatomie und Physiologie der Insecten, lste Monogr., 
Die weiblichen Geschlechtsorgane der Kafer, Berlin, 



(J. V^) Ueber die Entwickelung des Spinneneies, 
Zeitsch. f. wiss. Zool*, 1850, vol. 2, p. 97. — Dujar- 



1847, fol. fi *. — Siebold, (C. Th. E. v.,) Ueber die bin, (F.,) Memoire sur des Acariens sans bouches, 
Fortpflanzung von Psyche, Zeitsch. f. wiss. Zool., dont on a fait le genere Hypopus et qui sont le 

1848, vol. 1, p. 93. — Leydig, (Fr*,) Einige Remer- premier age des Gamaoses, Ann. Sc. Nat., 1849, 
kungen iiber die Entwickelung der Blattlause, Zeitsch. vol. 12, p. 243 et 259. 

f. wiss. Zool., 1850, vol. 2, p. 62. 

Ueber die Entwickelung des Fettkorpers, der Tra- 

cheen und der keimbereitenden Geschechtstheile bei f. wiss. Zool. 1851, vol. 3, p. 220. — VanBeneden, 



Meyer 



und 



2 Kaufmann, (Jos.,) Ueber die Entwickelung 
zoolodsche Stelluno* der Tard i or ad p.n . 7*£t*t*hl 



den Lepidopteren, Zeitsch. f. wiss. Zool., 1849, vol. 1 



(P. J.,) Recherches sur Torganisation et le develop- 



Burnett, (W. J^) Researches on the Develop- pement des Linguatules 



ma,) Mem. Ac. 



ment of viviparous Aphides, Amer. Journ. Sci. and Brux. vol. 15, I., p. 188. — Schubert, (T. D.,) 
Arts, 1854, vol. 17, p. 62 and 261. — As far as the 



Ueber Entwickelung von Pentastomum tenioides 

Wil- 



metamorphoses of Insects, after the eclosion of the Zeitsch. f. wiss. Zool. 1852, vol. 4, p. 117. 

larva, are concerned, I must refer to the works of SON, (E.,) Researches into the Structure and De- 

Reaumer and Roesel already quoted, and to almost velopment of a newly discovered Parasitic Animal- 

every modern book upon Entomology. The meta- cule of the Human Skin, Phil. Trans. R. Soc. 1844, 



morphoses of North American Insects are minutely 
described in Harris's Report, q. a. 



p. 305. 



3 Forchhammer, (G.,) De Blennii vivipari 



\ 


















. i 







1 














J 










s 






Chap. I. 



METAMORPHOSES OF ANIMALS. 



81 



toms differs greatly from that of 



ordinary fishes 



As it 



now stands in our 



sys- 



tems, the class of Fishes is certainly 



the most heterogeneous 



among Vertebrata 









4to. 



formatione et evolutione observations, Kiel, 1819, of the Salmon in Fresh Water, Ann. and Mag, Nat. 

Hist., IV. p. 334. — Duvernoy, (G. L.,) Observa- 
tions pour servir a la connaissance du developpement 
de la Pecilie de Surinam, An. Sc. Nat., 1844, 3e ser. 
I. p. 313, fig. — Coste, (P.,) Histoire generate et 
Bilduno-s- und Ent- particuliere du developpement des corps organises, 



Prevost, (J. L.,) De la generation chez le 
Sechot (Cottus Gobio), Mem. Soc. Phys. et Hist. Nat., 
Geneve, vol. 4, 1828, 4to.— Rathke, (H.,) Beitrage 
zur Geschichte der Thierwelt, Halle, 1820-27, 4 vols. 



4to. fig. 



Abhandlungen zui* 



■ 



wickelungsgeschichte des Menschen und der Thiere. 



Leipzig, 1832-33, 2 vols. 4to. fig. 



einiger Lachsarten, Meckel's Archiv, 1832, p. 392. 



■ 

Baer, (K. E. v.,) Untersuchungen iiber 
wickelungsgeschichte der Fische, Leipzig, 1835, 4to. 
Also Entw. der Thiere, q. a., vol. 2d. — Davy, 
(J.,) On the Development of the Torpedo, Philos. 
Trans. R. Soc, 1834. — Filippi, (Fil. de,) Memoria 
sullo sviluppo del Gobius fluviatilis, Anna. Medic, 
Milano, 1841, 8vo. fig. — Busconi, (M.,) Sopra la 
fecondatione artificiale nei pesci, Giorn. delle Sc 
Med.-chir., Pavia, vol. 9 ; tranls. in Muller's Archiv, 
1840, p. 185. — Lettre sur les changements que les 
oeufs de Poissons eprouvent avant qu'ils aient pris la 
forme d'embryon, Ann. Sc Nat., 2de ser. vol. 5; 



transl. Mag. Zool. and Bot., I., p. 586. 



Agassiz, 



(L.,) Histoire naturelle des Poissons d'eau douce de 
l'Europe centrale, vol. 1. Embryologie des Salmones, 
par C. Vogt, Neuchatel, 1842, 8vo. atlas fol. These 
investigations were made under my direction and 

Muller, (J.,) Ueber den glatten Hai 
des Aristoteles, und iiber die Verschiedenheiten unter 
den Haifishen und Rochen in der Entwickelung des 



supervision 



Eies, Berlin, 1842, fol. fig. 



Leuckart, (F. S.,) 



Untersuchungen iiber die iiussern Kiemen der Em- 
bryonen von Rochen und Haien, Stuttgardt, 1836, 



8vo. fig. 



Leydig, (Fr.,) Beitrage zur microscopis- 
chen Anatomic und Entwickelungsgeschichte der 
Rochen und Haie, Leipzig, 1852, 1 vol. 8vo. fig. 
Carus, (C. G.,) Erlauterungstafeln, etc., No. 3, Leip- 
zig, 1831, fol. %. — Shaw, (J.,) Account of some 

Experiments and Observations on the Parr, etc., 



Paris, 1847^-53, 4to., Atl. fol., 2d Fasc, Epinoche. 



Ueber das Ei Quatrefages, (Arm. de,) Memoire sur les Embry- 



Edinb. New Phil. Journ., vol. 2.1, p 



99. 



Development and Growth of the Fry of the Salmon 



? 



ons des Syngnathes, Ann. Sc. Nat., 2de ser. vol. 18, 



die Ent- p- 193, fig. — Sur le developpement embryonaire des 



Blennies, etc., Comptes-Rendus, vol. 17, p. 320. 

* 
I 

Valenciennes, (A.,) Anableps in Cuvier et Valen- 
ciennes, Histoire naturelle des Poissons, Paris, 1846, 



Wyman 



vol. 18, p. 245. 

Development of Anableps Gronovii, Journ. Bost. Nat. 



Hist., 



1854, vol. 6, fig. 



Agassiz, (L.,) Extra- 



ordinary Fishes from California, constituting a new 
family, Amer. Journ. Sc. and A., 1853, vol. 16, p. 380. 
Embryology of Lophius americanus, Proc. Am. Ac. 
2855. — Lereboullet, (A.,) Recherehes sur FAna- 
tomie des organes genitaux des animaux Vertebres, 
N. Act. Ac. Nat. Cur., vol. 23, p. 1. — Ann. Sc. Nat., 
4e ser. vol. 1. — Aubert, (H.,) Beitrage zur Ent- 

* 

wickelungsgeschichte der Fische, Zeitsch. f. wiss. 

Zool., 1853, vol. 5, p. 94; 1855, vol. 7. — Valen- 
tin, (G.,) Zur Entwickelungsgeschichte der Fische, 
Zeitsch. f. wiss. Zool., 1850, vol. 2, p. 267. — Leuck- 
art, (R.,) Ueber die allmahlige Bildung der Kcirper- 
gestalt bei den Rochen, Zeitsch. f. wiss. Zool., 1850, 
vol. 2, p. 258. — Haeckel, (E.,) Ueber die Eier der 

i 

Scomberesoces, Muller's Arch., 1855, p. 23. — Ret- 
zius, (A.,) Ueber den grossen Fetttropfen in den 



Eiern der 



Muller 



1855, p. 34. 



Bruch, (C.,) Ueber die Micropyle der Fische, 
Zeitsch. f. wiss. Zool., 1855, vol. 7, p. 172. 



Rei- 



chert, (K. B.,) Ueber die Micropyle der Fischeier, 
etc., Muller's Arch., 1856, p. 83. — Dowler, (B.,) 
Discovery of a Viviparous Fish in Louisiana, Amer. 



On the Jour. Sc. and Arts, 1855, vol. 19, p. 133, with Remark 



s 



by L. Agassiz, p. 136. 



(M 



etc., Ibid. vol. 24, p. 165; also Ann. Nat. Hist, L developpement des Petromyzons, Comptes-Rendus, 

Yarrell, (W.,) Growth 1856, p. 336; Ann. and Mag. Nat. Hist., 2d ser. 



p. 75, and IV. p. 352. 



11 






* 



\ 



















\ 


















I ! 















i^iL-i 1 



I 












■ 









: 









1 



































































A 







82 



SS.AY ON CLASSIFICATION. 



Part I. 



The disagreement of authors as to the limits and respective value of its orders and 
families may be partly 



owing to the unnatural circumscription of the class itself. 



As to the Reptiles, it is already, certain, that the Amphibia and Reptiles proper, so 



one class, constitute two distinct classes. 



In the main, the develop- 



long united as 

■ 

ment of the true Reptiles 2 agrees very closely with that of the Birds, while the 
Amphibians 3 resemble more the true fishes. In no class are renewed embryological 



t * 



1856, vol. 17, p. 443. — Muller, (A.,) Ueber die 
Entwickelung der Neunaugen, Miiller's Arch., 1856, 
p. 303. The unexpected facts mentioned here, render 
it highly probable, that Amphioxus is the immature 

- 

state of some marine Cyclostom. 

- 

1 The peculiarities of the development of the 
Plagiostoms consist not so much in the few large 
eggs they produce, and the more intimate connection 
which the embryo of some of them assumes with the 
parent, than in the development itself, which, not- 
withstanding the absence of an amnios and an allan- 



das Ei und den Foetus der Schildkrote, Heidelberg, 

■ 

1828, 4to. fig. — Baer, (K. E. v.,) Beitrage zur 
Entwickelungsgeschichte der Schildkroten, Miiller's 
Archiv, 1834, p. 544. — Rathke, (H.,) Ueber die 
Entwickelung der Schildkroten, Braunschweig, 1848, 



4to. fig. 






8 Rosel v. Rosenhof, (A. J.,) Historia natu- 
ralis Ranarum nostratium, etc., Norimb., 1758, fol. 

Funk, (A. F.,) De Salamandrae terrestris vita, 



fig. 



evolutione, formatione, etc., Berlin, 1826, fol. fig. 
Rathke, (H.,) Diss, de Salamandrarum corporibus 



tois, resembles closely, in its early stages, that of the adiposis eorumque evolutione, Berol, 1818. — Ueber 
Reptiles proper and of the Birds, especially in the die Entstehung und Entwickelung der Geschlechts- 
formation of the vascular system, the presence of a theile bei den Urodelen, N. Schr., Dantz. Naturf. Ges., 

sinus terminalis, etc. Again, besides the more ob- 
vious anatomical differences existing between the 
Plagiostoms and the bony Fishes, it should be remem- 
bered that, as in the higher Vertebrata, the ovary is metamorphosi quarumdam partium Ranae temporariae, 



1820. 



Steinheim, (L.,) Die Entwickelung der 



Frosche, Hamburg, 1820, 8vo. fig. — Hasselt, (J. 
Conr., van,) Dissert, exhibens Observationes de 



separated from the oviducts in the Sharks and Skates, 
and the eggs are taken up by a wide fallopian tube. 



Gottingae, 1820, 8vo. — Prevost, (J. L.,) et Lebert, 
Memoire sur la formation des organes de la circula- 



naissance jusqu 



? >, 



Milan 



fig. 



That the Plagiostoms can hardly be considered sim- tion et du Sang dans les Batraciens, Ann. Sc. Nat., 3e 
ply as an order in the class of Fishes, could already ser. I. p. 193, fig. — Rusconi, (M.,) Developpement 
be inferred from the fact, that they do not constitute de la Grenouille commune, depuis le moment de sa 

■ 

a natural series with the other Fishes. I would, 
therefore, propose the name of Selachians for a 
distinct class embracing the Sharks, Skates, and 
Chimseras. Recent investigations upon the Cyclos- 
toms, show them also to differ widely from the 
Fishes proper, and they too ought to be separated as 
a distinct class, for which the name of Myzontes 
may be most appropriate. 



Amours des Salamandres aquatiques et deve- 
loppement du Tetard de ces Salamandres, etc., Milan, 
1822, 4to. fig. — Baer, (K. E. v.,) Die Metamor- 
phose des Eies der Batrachier vor der Erscheinung 
des Embryo, etc., Miiller's Archiv, 1834, p. 481. 
Entwickelungsgeschichte, etc., vol. 2d, p. 280. 



Reichert, (K. B.,) Das Entwickelungsleben im Wir- 



2 Volkmann, (G. W.,) De Colubri Natricis belthierreich, Berlin, 1840, 4to. fig. 



Entwickelungsgeschichte des Kopfe 



Vergleichende 

o 

der nackten 



Generatione, Lipsias, 1834, 4to. — Rathke, (H.,) 

Entwickelungsgeschichte der Natter, (Coluber Na- Amphibien, etc., Konigsberg, 1838, 4to. fig. — Ueber . 

trix,) Konigsberg, 1839, 4to. fig. — Weinland, (D.,) den Furchungsprocess der Batrachier-Eier, Miiller's 

Ueber den Eizahn der Ringelnatter, "Wurt. Nat. Archiv, 1841, p. 523. — Vogt, (C.,) Untersuchungen 

Hist. Jahreshefte, 1855. — Tiedemann, (F.,) Ueber iiber die Entwickelungsgeschichte der Geburtshelfer- 





















»l 












Chap. I. 



METAMORPHOSES OF ANIMALS. 




\. 






investigations, extending over a 



tv of families, so mnch needed, as in that of 



Birds, though the general 
than that of any other typ 
a most successful and 



development of these animals is, perhaps, better known 
p- 1 while the class of Mammalia 2 has found in Bischoff 



thorough 



investigator. 



3 



• 






krote, Solothurn, 1841, 4to. fig. — Quelques observa- 
tions sur l'embryologie des Batraciens, Ann. Sc. n., 
3e ser. vol. 2, p. 45. — Remak, (R.,) Untersuchungen 



Wirbelthiere 



fol. 



assistance from the knowledge of their development 
for their natural classification* 

2 For the papers relating to the foetal envelopes 
and the placenta and also to the different systems 
of organs or any organ in particular and for human 
embryology generally, see Bischoff 's article " Ent- 
wickelungsgeschichte," in R. Wagner's Handworter- 
buch der Physiologie, p. 867, where every thing that 

Harn- und Geschlechtswerkzeuge der nackten Amphi- has been done in this direction, up to the year 1843, 

I is enumerated. For more recent researches upon 
these topics consult, also, Muller's Archiv, Wieg- 
man's Archiv, Siebold und Kolliker's Zeitsch. 



— Newport, (G.,) On the Impregnation of the 
Ovum in the Amphibia, Philos. Trans. R. Soc, 1851, 



I., p. 169. 



(W 



phologischen und histologischen Entwickelung der 



bien, Zeitsch. f. wiss. Zool., 1852, vol. 4, p. 125. 

■ 

Weinland, (D.,) Ueber den Beutelfrosch, Muller's 
Archiv, 1854, p. 449. — Wyman, (J.,) Observations 

- 

on Pipa americana, Am. Jour. Sc. and Arts, 2d ser. 
1854, vol. 17, p. 369. 

1 Pander, (Chr. H.,) Diss, sistens historiam 

metamorphoseos quam ovum incubatum prioribus 



quinque diebus subit, Wirceb. 1817, 8vo. 



Beit rage 






zur Entwickelungsgeschichte des Huhnchens im Eie, 
Wurzb. 1817, fol. fig. — Baer, (K. E. v.,) Entwicke- 
lungsgeschichte, etc., vol. 1. — Dutrochet, (H.,) 
Histoire de l'oeuf des Oiseaux avant la ponte, Bull. 
Soc. Philom., 1819, p. 38. — Hunter, (John,) Obser- 

vations on Animal Development, edited and his Illus- 
trations of that process in the Bird described by R. 
Owen, London, 1841, fol. fig. — Prevost, (J. L.,) 
Memoire sur le developpement du poulet dans l'oeuf 

■ 

Ann. Sc. Nat., 1827, vol. 12, p. 415. 



Prevost, (J. 

L.,) et Lebert, Memoires sur la formation des 
organes de la circulation et du sang dans l'embryon 
du Poulet, Ann. Sc. Nat. 3e ser. I. p. 265 ; II. p. 222, 
fig.; III. p. 96. — Baudrimont, (A.,) et Martin St. 
Ange, (G. J.) Recherches anatomiques et physiolo- 



or 



■ 

iques sur le developpement du foetus, Paris, looO, 

Meckel, v. Hemsbach, (H.,) Die Bildung der 



4to. 



fiir partielle Furchung bestimmten Eier der Vogel, 
etc., Zeitsch. f. wiss. Zool., 1852, vol. 3, p, 420. 
In no class are embryological investigations extend- 



ing over a 



variety of families more needed than 
in that of Birds, if we should ever derive any 



f. wiss. Zool., Milne-Edwards, Ann. Sc. Nat., and 
the Annals and Magazine of Nat. Hist., etc. 

3 Bischoff, (Th. L. W.,) Entwickelungsges- 
chichte des Kaninchen-Eies, Braunschweig, 1842 
4 t0> flg. — Entwickelungsgeschichte des Hunde-Eies, 



Braunschweig, 1845, 4to. 



fig. 



■ 

Entwickelungsges- 



chichte des Meerschweinchens, Giessen, 1852, 4to. fig. 
Entwickelungsgeschichte des Rehes, Giessen, 1854, 

4 t0# flg # — Preyost, (J. L.,) et Dumas, (J. A.,) De 

la generation chez les Mammiferes, etc., Ann. Sc. Nat. 
1824, vol. 3, p. 113, fig. — Bojanus, (L.,) Observatio 
anatomica de foetu canino 24 dierum, etc., Act. Ac. 
Nat. Cuv., vol. 10, p. 139, fig. — Coste, (P.,) Embry- 
oo-enie comparee, Paris, 1837, 8vo. Atlas 4to. 
toire particuliere et generale du developpement des 

Recherches sur le generation 



His- 



corps organises, q. a. 
des Mammiferes et le developpement de la brebis, 
Ann. Sc. Nat., 1835, III. p. 78. — Recherches sur 
la generation des Mammiferes, Paris, 1834, 4to. fig. 
Bernhardt, (C. A.,) Symbols ad Ovi Mamma- 
Hum historiam ante pregnationem, Vratisl., 4to., Mul- 
ler's Arch., 1835, p. 228. — Barry, (M.,) Researches 
in Embryology, Phil. Trans. P. Soc. 1838, p. 301 ; 
1839, p. 307 ; 1840, p. 529 ; 1841, p. 195. — Baer, 
(H. E. v.,) q. a. — Owen, (R,,) On the Ova of 

the Ornithorhynchus paradoxus, Phil. Trans. 1834, 



p. 555. 



On the Young of the Ornithorhynchus para- 












! 



i 























I 









































































84 



ESSAY ON CLASSIFICATION. 



Part I. 






Embryology lias, however, a wider scope than to trace the growth of individual 



animals, the gradual building up of their body, the formation of tt 
the changes they undergo in their structure and in their form 



eir organs, and all 

; it ought also to 

of these forms and the successive steps of these changes 

between all the types of the animal kingdom, in order to furnish definite standards 

of their relative 



embrace 



a comparison 



standing, 



of their affinities, of the correspondence of their organs in 



all their parts. Embryologists have thus far considered too exclusively, the gradual 
transformation of the egg into a perfect animal; there remains still a wide field of 
investigation to ascertain the different degrees of similarity between the successive 
forms an animal assumes until it has completed its growth, and the various forms of 

■ 

different kinds of full-grown animals of the same type; between the different stages 
of complication of their structure in general, and the perfect structure of their 

s 

kindred; between the successive steps in the formation of all their parts and the 

groups ; between the normal 
course of the whole development of one type compared with that of other types, as 
well as between the ultimate histological differences which all exhibit within certain 

■ 

w 

■ 

limits. Though important fragments have been contributed upon these different 



various degrees of perfection of the parts of other 



- 

points, I know how much remains to be done, from the little I have as yet been 

■ 

able to gather myself, by systematic research in this direction. 

■ 

I have satisfied myself long ago, that Embryology furnishes the most trustworthy 

A careful comparison of 



standard to determine 



the relative rank among animals 






the successive stages of development of the higher Batrachians furnishes, perhap 
most striking example of the importance of such investigations. 



The earlier stages 



of the Tadpole exemplify the structure and form of those Ichthyoids which have 
either no legs, or very imperfect legs, with and without external gills ; next it 
assumes a shape reminding us more of the Tritons and Salamanders, and ends with 



the structure 



of the Frog or Toad. 1 



A comparison between the two latter families 

■ 

might prove further, that the Toads are higher than the Frogs, not only on account 
of their more terrestrial habits (see Sect. 16), but because the embryonic web, which, 
to some extent, still unites the fingers in the Frogs, disappears entirely in the Toads, 
and may be also, because glands are developed in their skin, which do not exist in 
Frogs. A similar comparison of the successive changes of a new species of Comatula 

in South Carolina, has 

>s stand to 



discovered by Prof. Holmes, in the harbor v of Charleston, 

shown me in what relation the different types of Crinoids of past 



■g 















doxus, Trans. Zool. Soc, i. p. 221 ; Proc. Zool. Soc, (Ch.,) Observations on the Keproductive Organs and 

ii. p. 43; Ann. Sc. Nat., 2d ser. ii. p. 303; iii. on the Foetus of Delphinus Nesarnak, Journ. Ac. 

r ( ' . 

p. 299. — On the Generation of the Marsupial Ani- Nat. Se. Phil., new ser. 1849, vol. 1, p. 267. 

■ 

1 Agassiz, (L.,) Twelve Lectures, etc., page 8. 



mals, etc., Phil. Trans., 1824, p 



333. 



Meigs, 




























..»"* 














V 











Chap. I. 



METAMORPHOSES OF ANIMALS. 



85 



v, 



» L 

these changes, and has furnished a standard to determine their relative rank ; 



as 



it cannot be doubted, 



that the earlier stages 



» 



of growth of an animal exhibit a 



condition of relative inferiority, when contrasted with what it grows to be, after 
it has completed its development, and before it enters upon those phases of its 

and certain curious retrograde metamorphoses 



existence which constitute old age, 
observed among parasites. 



In 



the youno- 



& 



Comatula there exists a stem, by which the little animal is 



attached, either to sea weeds, or 



to the cirrhi of the parent; the stem is at first 



simple and without cirrhi, supporting 



are 



globular head, upon which the so-called arms 
next developed and gradually completed by the appearance of branches; a few 
cirrhi are, at the same time, developed upon the stem, which increase in number 
until they form a wreath between the arms and the stem. At last, the crown 

diminutive Comatula, drops off, freeing itself 



having assumed all the characters of a 



from the stem, and the Comatula moves freely as an independent animal. 



1 



The classes of Crustacea and of Insects, 2 are particularly instructive in this 

Rathke, however, has described the transformations of so many Crustacea, 

refer to his various papers upon this subject, 3 for 

imals undergo during their earlier stages of 



respectM 

that I cannot do better than to 



details relating to the changes these am 



growth. I 



would only add, that while the embryo of the highest Crustacea, the 

Brachyura, resembles by Its form and structure the lowest types of this class, as the 

Entomostraca and Isopoda, it next assumes the shape 

the Macroura, before it appears with all the characteristics of the Brachyura, 

Embryology furnishes, also, the best measure of the true affinities existing 



of those of a higher order, 



between animals. I do not mean to say 



that the affinities of animals can only be 



it i. ' • • +;™»+;™i«. tbp historv of Zoology shows, on the con- 

ascertained by embryonic investigations, tne iiifetuij &J , 



trary, that even 



before the study of the formation and 




rowth of animals had 



become a 



distinct branch of physiology, the general relationship 



of most animals had 



already been determined, with a remar 



kable degree of accuracy, by 



anatomical inves- 



tigations. 



It is, nevertheless, true, that in some 



remarkable instances, the knowledge 



of the embryonic changes of certain animals gave the first clue to their true affini- 
ties, while, in other cases, it has furnished a very welcome confirmation of relation- 

Even 



ships, which, before, could appear 



probable, but were still very problematical. 



Cuvier considered, for instance, the Barnacles as a distinct class, which he placed 






1 A condensed account of the transformations of 



E. 

10. 



the European Comatula, may be found in 
Forbes's History of the British Starfishes, p. 
The embryology of our species will be illustrated 

■ 

in one of my next volumes. 



2 See Agassiz's Twelve Lectures, p. 62, and 
Classification of Insects, etc., q. a. It is expected 

> 

that Embryology may furnish the means of ascer- 
taining the relative standing of every family. 
8 See above, page 79, note 2. 












. 




































■ 



! . 















' 

















. 

















86 



ESSAY ON CLASSIFICATION. 



Part I 





























































among 



Mollusks, under the name of Cirripeds. It was not until Thompson 1 had 
shown, what was soon confirmed by Burmeister and Martin St. Ange, that the 

young Barnacle has a structure and form identical with that 



of some of the most 



common Entomostraca, that their true position in the system of animals could be 
determined; when they had to be removed to the class of Crustacea, among Articu- 
lata. The same was the case with the Lernaeans, which Cuvier arranged with the 
Intestinal Worms, and which Nordmann has shown upon embryological evidence to 






belong also to the class of Crustacea 



and though they 



1 Lamarck associated the Crinoids with Polypi, 

* 

emoved to the class of Echinoderms by Cuvier, before the 
metamorphoses of the Comatula were known, 3 the discovery of their pedunculated 
young furnished a direct proof that this was their true position. 

Embryology affords further a test for homologies in contradistinction of analogies. 

- 

It shows that true homologies are limited respectively within the natural boundaries 
of the great branches of the animal kingdom. 

The distinction between homologies and analogies, upon which the English natu- 

ralists have first insisted, 4 has removed much doubt respecting the real affinities of 
animals which could hardly have been so distinctly appreciated before. It has 



ght us to distinguish between real affinity, based 



upon structural conformity, and 



similarity, based upon mere external resemblance in form and habits 



But 



after 



this distinct 



- 

had b 



limits homologies 



fairly established/ it remained to determine within what 
may be traced. The works of Oken, Spix, Geoffroy, and Cams, 5 
show to what extravagant comparisons a preconceived idea of unity may lead. It 
was not until Baer had shown that the development of the four great branches of 
the animal kingdom is essentially different, 6 that it could even be suspected that 

- 

organs performing identical functions may be different in their essential relations to 

one another, and not until Eathke 7 had demonstrated that the yolk is in open 

cavity of the Articulata, on the dorsal side of the 



communication with the main cav 

* 

animal, and not on the ventral side, as 



tained for the natural limitation of true homolog 



Yertebrata, that a solid basis was ob- 

es. It now appears more and 



i 

more distinctly, with every step of the prog 



Embryology is making, that the 



structure of animals is only homologous within the limits of the four great branches 






1 Thompson's Zool. Researches, etc. ; Burmeis- 
ter's Beitrage, etc. ; Martin St. Ang-e, Mem. sur 
l'organisation, etc., quoted above, page 79, note 1. 

2 Nordmann's Mierographische Beytrage, q. a. 

3 Thompson and Forbes, q. a., page 79. 

4 Swainson's Geography and Classification, etc. 
See above, Sect. V., p. 20. 



5 See, above, Sect. IV., notes 1 and 2. 

6 Baer's Entwickelungsgeschichte, vol. 1, p. 160 
and 224. The extent of Baer's information and the 
comprehensiveness of his views, nowhere appear so 
strikingly as in this part of his work. 

7 Rathke's Unters. tiber Bild., etc., see, above, p. 
79, note 2. 






s ' 



\ 






I 



V 

















Chap. I. 



METAMORPHOSES OF ANIMALS 



87 



\ 



of the animal kingdom, and that general homology strictly proved, proves also 
typical identity, as special homology proves class identity. 



The results of all embry 



gations of modern times go to show more 



and 



more 



ely, that animals are 



ely independ 



of external causes in 



their development. The identity of the metamorphoses of oviparous and 
animals belonging to the same typ 



furnishes the most convincing evidence 



that 



effect 



i 



Formerly 



was 



pposed that the embryo could be affected directly by 



external influences to such an extent, that monstrosities, for instance, were ascribed 



the influence of external causes. 



Direct observation has shown, that they are 



founded upon peculiarities of the normal course of their development 



2 



The 



g 



berth in which the young underg 



their first transformation in the womb of their 



mother in all Mammalia, excludes so completely the immediate influence of any 






external agent, that it is only necessary 
their growth must be of the circumstance 



allude to it, to show how independent 
which even the mother may be placed. 






Th 



qually 



of all other viviparous 



snakes 



sharks 






and the viviparous fishes. Ag 
and the exclusion, to 



the uniformity of temperature in the nests of birds 



a certain deg 



of influences which might otherwise reach 



them, in the 



their 



g 



3 



various structures animals build for the protection of their young or of 
show distinctly, that the instinct of all animals leads them to remove 



their progeny from the influence of physical ag 



'? 



or to make these agents sub 



o 



servient to their 



purposes 



as 



in the case 



of the ostrich. Reptiles and terrestrial 



Mollusks bury their 



g 



to subtract them from varying influences ; fishes dep 



them in localities where they 



posed 



the least changes. Insects 



theirs 






1 This seems the most appropriate place to re- 
mark, that the distinction made between viviparous 



■ 

based is, of course, the mode of development of the 

In this respect we find that Selachians, whe- 

_ 



mark, that the distinction made between viviparous germ. In tins respect we nnu u^ remans, wne- 
and oviparous animals is not only untenable as far as ther oviparous or viviparous, agree mth one another ; 
their first origin in the ear is concerned, but also un- this is also the case with the bony fishes and the rep- 



their first origin in the egg is concerned, but also un- 
physiological, if it is intended, by this designation, to 
convey the idea of any affinity or resemblance in their 
respective modes of development. Fishes show more 
distinctly than any other class, that animals, the devel- 
opment of which is identical, in all its leading feat- 
ures, may either be viviparous or oviparous ; the dil- 
ference here arising only from the connection in 
which the egg is developed, and not from the devel- 
opment itself. Again, viviparous and oviparous ani- 
mals of different classes differ greatly in their devel- 
opment, even though they may agree in laying eggs 
or bringing forth living young. The essential feature 
upon which any important generalization may be 



. - 



this is also the case with the bony fishes and the rep- 
tiles whether they are respectively oviparous or vivi- 

* 

parous ; even the placentalian and non-placentalian 
Mammalia agree with one another in what is essential 
in their development. Too much importance has thus 
far been attached to the connections in which the germ 
is developed, to the exclusion of the leading features 

* 

of the transformations of the germ itself. 

2 Bishofp, (Th. L. W.,) in R. Wagner's Hand- 



worterbuch der Physiologie, Article " Entwickelungs- 
geschichte," p. 885. 

8 Burdach's Physiologie, etc., q. a. vol. 2, 2d ed. 

Sect. 334-38. See, also, Kirby and Spence's Intro- 
duction, etc., q. a. 























































« 






















r f 






f 


















m 















I 












I 





































88 



ESSAY ON CLASSIFICATION. 



Part I. 



ways 



Most marine animals living in extreme climates, lay their 



« 



in 



winter, when the variations of external influences are reduced to a minimum. 
Everywhere we find evidence that the phenomena of life, though manifested in the 
midst of all the most diversified physical influences, are rendered independent of 
them to the utmost degree, by a variety of contrivances prepared by the animals 
themselves, in self-protection, or for the protection of their progeny from any influ- 
ence of physical agents not desired by them, or not subservient to their own ends. 



SECTION XIX 



■ 



DURATION OF LIFE. 


























There is the most extraordinary inequality in the average duration of the life of 

■ 

different kinds of animals and plants. While some grow and reproduce themselves 
and die in a short summer, nay, in a day, others seem to defy the influence of 
time, 1 



Who has thus apportioned the life of 



all organized being 



To answer 



this 



question, let us first look at the facts of the case. In the first place, there is no 
conformity between the duration of life and either the size, or structure, or 



habitat 



of animals 



the system, in which the changes occurring during any period 



regulated, differs in almost every species, there being only a slight de 
formity between the representatives 



of 



uni- 



of different classes, within 



limits 



In most Fishes and the Keptiles proper, for 



the growth is very gradual 



and uniform, and their development continues through life, so much so that their 



size is continually increasing with age. 



In others, the Birds, for 



the growth 



pid during the first period of 



their life, until they have acquired their full size, and then follows a period of equi 
librium, which lasts for a longer or shorter period in different species. 



In others 



still, which also acquire within certain limits a definite size, the Mam- 
malia, for instance, the growth is slower in early life, and maturity is attained, as in 
man, at an age which forms a much longer part of the whole duration of life. 

In Insects, the period of maturity is, on the contrary, generally the shortest, 
while the growth of the larva may be very slow, or, at least, that stage of develop- 



ment last for a much longer time than the life of the perfect Insects 



There 






> 






1 Schubler, (Gust.,) Beobachtungen iiber jahr- 
liche periodisch wiederkehrende Erscheinungen im 



Thier- und Pflanzenreich, Tubingen, 1831, 8vo. 
Quetelet, (A.,) Phenomenes periodiques, Ac. Brux. 





















Chap. I. 



DURATION OF LIFE. 



89 







more striking example of this peculiar mode of growth than the seventeen years 
locust, so fully traced by Miss M. H. Morris. 1 

While all longlived animals continue, as a matter of course, their existence 
through a series of years, under the varying influence of successive seasons, there 
are many others which are periodical in their appearance; this is the case with most 
insects, 2 but perhaps in a still more striking manner with Medusas. 3 



The most interesting point in 



this subject is yet the change of character which 



takes place in the different stages of growth of one and the same animal. Neither 



Vertebrata, nor Mollusks, nor 



even Radiata exhibit in this respect any thing so 



remarkable 



in the continuous changes which an individual animal may undergo, as 

those with so-called complete metamorphoses, in which 



the Insects, and among them 

the youno- 



© 



(the larva) may be an 



active, wormlike, voracious, even carnivorous 



being, which in middle life (the chrysalis) becomes a mummylike, almost motionless 



maggot, incapable of taking food, ending 



life as a winged and active insect. 



Some 



of these larvaa may be aquatic and very voracious, when the perfect insect is aerial 



and takes 



food at all. 4 



Is there any thing in this regulation 



of the duration of life in animals which 



recalls the agency of physical forces ? Does not, on the contrary, the fact, that 
while some animals are periodical and bound to the seasons in their appearance, 



and others 



independent of the 



of the year, show distinctly their independ 



ence 



causes 



of all those influences which, under a common expression, are called physical 
? Is this not further illustrated in the most startling manner by the extraor- 

which one and the same animal may undergo 

i 

? Does this not prove directly the immediate 



dinary changes, ab 



alluded 



during different periods of its life 



of 



a power 



pable of controlling all these external 



well 



as regulating the course of life of every being, and establishing it upon such 



immutable foundation, within 



ycle of changes, that the 



pted action of 



these agents shall not interfere with the regular order of their natural 



There 



however, still another conclusion to be drawn from these facts 



they 



point distinctly at a discriminatin 



knowledge of time and space, at 



ppreciation 



of the relative value of unequal amounts of time and an unequal repartition of 



small, unequal periods over longer periods, which 
thinking being. 



can 




be the attribute of 



a 



« 

1 Harris's Insects injurious to Vegetation, p. 184. 

2 Herold, (E.,) Teutscher Kaupen-Kalender, 



4 Burmeister's Handb. d. Entom. etc. — Lacor- 
daire, Introd. a l'Entomologie, etc. — Kirbt and 
Spence, Introd. to Entomol., etc., q. a., give accounts 
8 Agassiz's Acalephs of North America, p. 228. of the habits of Insects during their metamorphosis. 

12 



Nordhausen, 1845. 















■ 


















































































90 



ESSAY ON CLASSIFICATION 



Part I. 




































I 





























SECTION XX. 



ALTERNATE GENERATIONS. 



While some animals go on developing gradually from the first formation of their 



the natural end of their life, and bring forth g 



after 



gularity through the same course, there 



germ tol 

progeny which runs with never varying 

■ 

are others which multiply in various ways, by division and by budding, 1 or by a 
strange succession of generations, differing one from the other, and not returning, by 
a direct course, to their typical cycle. 

■ 

The facts which have led to the knowledge of the phenomena now generally 
known under the name of alternate generation, were first observed by Chamisso and 
Sars, and afterwards presented in a methodical connection by Steenstrup, in his 
famous pamphlet on that subject. 2 As a brief account of the facts may be found in 
almost every text-book of Physiology, I need not repeat them here, but only refer 
to the original investigations, in which all the details known upon this subject may 
be found. 3 These facts show, in the first place with regard to Hydroid Medusae, that 






the individuals born from eggs, may be 



ely different from those which produced 



themselves such chang 



as 



the eggs, and end their life without ever undergoing 

would transform them into individuals similar to their parents; 4 they show further 



1 Much information useful to the zoologist, may 
be gathered from Braun's paper upon the Budding 

■ 

of Plants, q. a., p. 18, note 3. The process of multi- 



2d ser. vol. 8, 1857, p. 59. — Prosch, (V.,) Om 
Parthenogenesis og Generationsvexel et Bidrag til 
Generationsheren, Kiobenhavn, 1851. — Leuckart, 



plication by budding or by division, and that of sexual (R.,) Ueber Metamorphose, ungeschlechtliche Ver- 



reproduction, are too often confounded by zoologists, 
and this confusion has already led to serious mis- 

9 

constructions of well known facts. 

2 Steenstrup, (J.,) Ueber den Generationswech- 

sel, q. a., p. 69, note 3. 

3 See the works quoted above, page 69, note 3, 



mehrung, Generationswechsel, Zeitscli. f. wiss. Zool,, 
vol. 3, 1851. — Dana, (J. D.,) On the Analogy 
between the Mode of Reproduction in Plants and the 
" Alternation of Generations" observed in some 
Radiata, Amer. Journ. A. and Sc, 2d ser. vol. 10, 



p. 341. 



Ehrenberg, (C. G.,) Ueber die Formen- 



and p. 70, note 1, also Carus, (V.,) Zur nahern Kennt- bestandigkeit und den Entwickelungskreis der orga- 



nischen Formen, Monatsber. der Akad., Berlin, 1852, 
8vo. 



niss des Generations wechsels, Leipzig, 1849, 8vo. 
Einige Worte liber Metamorphose und Generations- 
wechsel, Zeitsch. f. wiss. Zool., 1851, vol. 3, p. 359. 4 Polymorphism among individuals of the same 

Owen, (R.,) On Parthenogenesis, or the Succes- species is not limited to Acalephs ; it is also observed 

sive Production of Procreating Individuals from a among genuine Polyps, the Madrepores, for example, 

single Ovum, London, 1849, 8vo. — On Metamor- and among Bryozoa, Ascidians, Worms, Crustacea 

phosis and Metagenesis, Ann. and Mag. Nat. Hist, (Lupea), and even among Insects (Bees). 













I 






Chap. I. 



ALTERNATE GENERATIONS 



91 



that this brood originating from eggs, may 



and multiply by produ 



new 



individuals like themselves (Syncoryne 



of 



kinds (Campanularia), or even indi 



viduals of various kinds, differing all to a remarkable extent, 



from the other 



but 



neither case resembling their common parent 



N 



of these 



(Hydractinia,) 

new individuals have distinct reproductive organs, any more than the first indi- 



viduals born from 



eggs, 



their multiplication takin 



o 




chiefly by the process of 



budding 



but 



as 



these buds remain generally connected with the first individual 



born from an eo-o-, they form compound communities, similar to some polypstocks 
Now some of these buds produce, at certain seasons, 



new buds of an 



tirely differ- 



kind, which generally drop off from the parent stock 



at an early period of their 
and then undergo a succession of 



development, (as in Syncoryna, Campanularia, etc.,) 

changes, which end by their assuming the character of the previous egg-laying 



individuals, organs of reprodu 



of the two sexes develop 



which, when mature, lead to the product 



of 



g 



g meanwhile in them 
others (as in Hydrac- 



tinia,) the buds of this kind do 



drop off, but fade away upon the parent stock 



after having underg 
number of eggs. 1 



a 




their transformations, and also produced in due time, a 



In the case of the Medusae proper, 2 the parent lay 



g 



from which 



g 



polyplike individuals 



but here these individuals divide by transverse constrictions 



into 



number of disks, every one 



of which undergoes a succession of changes, which 



end in the production of as many 



dividuals, each identical with the parent, and 



pable in its 



of lay 



o-s (some, however, being males and others females.) 



But the polyplike individuals born from 



g' 



may also multiply by budding and 



each bud undergo the same chang 



the first, the base of which does 

■ 

also capable of growing up again and of repeating the same process 
In other classes other phenomena of a 



die, but 



which bear a similar explanation 



similar character have been observed 
J. Miiller 3 has most fully illustrated the alter- 



nate 



g 



of the Echinoderms 



Chamisso, Steenstrup, Eschricht, Krohn, and 



Sars, those of the Salp 

i 

tinal Worms. 5 

This alternate gen 



4 



Siebold Steenstrup, and others, those of certain Intes 



k 

differs 



lly from metamorphosis, though some 



1 I have observed many other combinations of a 
similar character among the Hydroid Medusa, which 
I shall describe at full length in my second volume ; 
and to which I do not allude here, as they could not 



Siphonophora, see the works quoted above, p. 69, 



note 3. 



be understood without numerous drawings. 



The 



case of Hydractinia is not quite correctly repre- 
sented in the works in which that animal has been 
described. Respecting Physalia and the other 



2 See Siebold, and Sars, q. a., p. 69, note 3. 
8 Muller, (J.,) Ueber den allgemeinen Plan, 
etc., q. a., p. 70, note 1. 

4 See the works, q. a., page 72, note 4. 

5 See the works, q. a., page 76, note 2, and 77, 
note 1. 























i 



; 










. 







! ! 
















^^ ^r 



^m 

























































1 































































Jt 



* 



92 



ESSAY ON CLASSIFICATION. 



Part I 



writers have attempted to identify these two processes. In metamorpho 



as 



observed among Insects, the individual born from an egg g 



undergoing chan 



after chang 



direct and immediate succession, until it has reached 



final 



formation; but however different it may be at different periods of its life, it is 
always one and the same individual. In alternate generations, 



derations, the individual born 
from an earar never assumes through a succession of transformations the character of 




its parent, but produces, either by internal or external budding or by division, a 



number, sometimes even a large number of new individuals, and 



gg 



which grows 



to assume again the 



this progeny 
characters of 



of the individuals born from < 

■- 

the egg-laying individuals. 

There is really an essential difference between the sexual reproduction of most 
animals, and the multiplication of individuals in other ways. In ordinary sexual 
reproduction, every new individual arises from an egg, and by a regular succession 
of changes assumes the character of its parents. Now, though all species of animals 
reproduce their kind by eggs, and though in each there is at least a certain number 



of individuals, if 



not the 



which have sprung from eggs, this mode of reproduct 




1 how new individ 
sexual individuals 



one observed among animals. We have already 
uals may originate from buds, which in their turn may prod 
we have also seen how, by division, individuals may also produce other individuals 
differing from themselves quite as much as the sexual buds, alluded to above, may 
differ from the individuals which produce them. There are yet, still other com- 
binations in the animal kingdom. In Polyps, for instance, every bud, whether it 
is freed from the parent stock or not, grows 

individual; while in many animals which multiply by division, every 
thus produced assumes at once the characters of those born from 



at once up 



to be a new sexual 



individual 



gi 



is, finally, one mode of reproduction which is peculiar to certain Insects 



There 
which 



several g 



of fertile females follow one another, before males appear ag 



2 



What comprehensive views the physical agents must be capable of 



g 



and 



what a power of combination they must possess, to be able to ingraft all these 
complicated modes of reproduction upon structures already so complicated! — 



if we 



away from mere fancies and consider the wonderful phenom 



But 
just 



alluded to, in all their bearings, how instructive they appear with reference to this 



very question of the infl 



of physical agents upon organized bein 



5 



For her 



we have animals endowed with the power of multiplying in the most extraordinary 

■ 

ways, every species producing new individuals of its own kind, differing to the utmost 
from their parents. Does this not seem, at first, as if we had before us a perfect 









Milne-Edwards, Rech. anat. et zool. faites pen- 



2 Owen, Parthenogenesis, etc., q. a., p. 90. — Bon- 



dant un Voyage sur les cotes de Sicile, 3 vols. 4to. fig. net, (Ch.,) Traite d'Insectologie, etc., Paris, 1745. 












l k*r 






















Chap. I. 



SUCCESSION OF ANIMALS AND PLANTS. 



93 



exemplification of the manner in which different species of animals may originate, one 
from the other, and increase the number of types existing at first? And yet, with all 
this apparent freedom of transformation, what do the facts finally show ? That all 
these transformations are the successive terms of a cycle, as definitely closed within 
precise limits, as in the case of animals, the progeny of which resembles for ever 



the immediate parent, in 



all successive generations. For here, as everywhere in 



the 



organic 



kingdoms, these variations are only the successive expressions of a 



well regulated cycle, ever returning 



to its own type. 






I 






i 

I 






SECTION 



XXI 






SUCCESSION OF ANIMALS AND PLANTS IN GEOLOGICAL TIMES 







Geologists hardly seem to appreciate 



fully, the whole extent of the intricate 



relations exhibited by the animals and plants 



whose remains are 



found 



m 



the 



different successive geological formations. 



I do not mean to say, that the investi- 



,. ,- _ ,i „ r^nlnmVfll and botanical characters of these remains 

gations we possess respecting the zoological <uiu uuu. 



are not remarkable for the accuracy 



and for the ingenuity with which they have 



been traced. On the contrary, having myself thus far devoted the better part of 
my life to the investigation of fossil remains, I have learned early, from the difficul- 
ties inherent in the subject, better to appreciate the wonderful skill, the high 



intellectual 



powers 



the vast erudition displayed in 



the investigations 



and his successors upon the fauna3 



and florae of past ages. 



i 



of Cuvier 
But I cannot refrain 






1 Cuvier, (G.,) Recherches sur les Ossemens 
fossiles de Quadrupedes, etc., Paris, 1812, 4 vols. 
4to.; nouv. edit. Paris, 1821-23, 5 vols. 4to.; 4e 



edit. 10 vols. 8vo. and 2 vols. pi. 4to. 



So WERE Y, 



(James,) The Mineral Conchology of Great Britain, 
London, 1812-19, 6 vols. 8vo. fig. — Schlottheim, 
(E. F. v.,) Die Petrefactenkunde, etc., Gotha, 1820, 
8vo. fig. — Lamarck, (J. B. de,) Memoires sur les 
fossiles des environs de Paris, Paris, 1823, 4to. ng. 
Goldfuss, (G. A.,) Petrefacta Germanias, Diissel- 

dorf, 1826-33, fol. fig. — Sternberg, (Kaspar, M. 

Gr. v.,) Versuch einer geognostisch-botanischen Dar- 
stellung der Flora der Vorwelt, Leipzig und Prag, 



1820-38, fol. fig. 



Brongniart, (Ad.,) Prodrome 

1818, 



d'une Histoire des Vegetaux fossiles, Pans, 



2 vols. 8vo. — Histoire des Vegetaux fossiles, Paris, 
1828-43, 2 vols. 4to. fig. — Lindley, (J.,) and Hut- 
ton, (W.,) The Fossil Flora of Great Britain, Lon- 
don, 1831-37, 3 vols. 8vo. — Goppert, (H. R.,) 
Systema Filicum fossilium, Vratisl. et Bonnse, 1836, 
4to. fig. — Di e Gattungen der fossilen Pflanzen, ver- 
glichen mit denen der Jetztwelt, etc-, Bonn, 1841- 
48, 4to. fig. — Monographie der fossilen Coniferen. 
Dusseldorf, 1850, 4to. fig. — More special works are 
quoted hereafter, but only such works shall be men- 
tioned, which have led on, in the progress of Geology 
and Paleontology, or contain full reports of the pres- 



ent state of our science, and also such 



as 



have 



special reference to America. References to the 
description of species may be found in Bronn, 












!! 




























^v 







































94 



ESSAY ON CLASSIFICATION 



Part I 

























































from expressing my wonder at the puerility of the discussions in which 



some 



geol- 



ogists allow themselves still 
digested facts 






to indulge, in the face of such a vast amount of well 
as our science now possesses. They have hardly yet learned to see 
that there exists a definite order in the succession of these innumerable extinct 
beings; and of the relations of this gradation to the other great features exhibited 
by the animal kingdom, of the great fact, that the development of life is the promi- 
nent trait in the history of our globe, 1 they seem either to know nothing, or to 



look 



upon 



it only as a vague speculation, plausible perhaps, but hardly deserving 



it has had to fight its 



the notice of sober science. 

It is true, Palaeontology as a science is very young; 
course through the unrelenting opposition of ignorance and prejudice. What amount 
of labor and patience it has cost only to establish the fact, that fossils are really 



the remains of animals and plants that once actually lived upon earth, 2 only those 
know, who are familiar with the history of science. Then it had to be proved, 
that they are not the wrecks of the Mosaic deluge, which, for a time, was the 

ivier had shown, beyond 



prevailing opinion, even among scientific men 



After C 



question, that they are the remains of animals no longer to be found upon earth, 

acquired for the first time a solid basis. Yet what 



among 



the 



living, Palaeontology 



- 

an amount of labor it has cost to ascertain, by direct evidence, how these remains 



are distributed in the solid crust of our globe, what 



the differences they exhibit 



in successive formations/ what is their geographical distribution, only those can 






i 










(H. G.,) Index palaeontologicus, Stuttgart, 1848-49, 



■ 

For references respecting the fossils of the 



3 vols. 8vo. — See also, Keferstein, (Chr.,) Ge- oldest geological formations, see the works, quoted 



schichte und Literatur der Geognosie, Halle, 1840, 



above, p. 23, note 1. Also, McCoy, (F.,) Synopsis 



1 vol. 8vo. — Archiac, (Vic. d',) Histoire des pro- of the Silurian Fossils of Ireland, Dublin, 1846, 4to. 



gres de la Geologie, Paris, 1847, et suiv, 4 vols. 
8vo. ; and the Transactions, Journals, and Proceed- 



fig. 



Geinitz, (H. D.,) Die Versteinerungen der 



Grauwackenformation, Leipzig, 1850-53, 4to. fig. 



ings of the Geological Society of London, of Paris, And for local information, the geological reports of 

> 

of Berlin, of Vienna, etc.; also, Leonhard and the different States of the Union, a complete list of 
Bronn's Neues Jahrbuch, etc. 



1 Agassiz's Geological Times, etc., q. a., p. 25, 



which, with a summary of the Geology, may be found 

5 (J.,) Resume explicatif d'une carte 



in Marcou 



note 2. — Dana's Address to the Amer. Ass, for Adv. geologique des Etats-Unis, Bull. Soc. Geol. de 



Sc. 8th Meeting, held at Providence, 1855. 



France, Paris, 1855, 2de ser. vol. 12. — For the 



Scilla, (Ag.,) La vana speculazione desin- Devonian system : Phillips, (John,) Figures and 



gannata dal senso. Napoli, 1670, 4to. fig. 



Descriptions of the Palaeozoic Fossils of Cornwall, 



3 



Scheuchzer, (J. J.,) Homo Diluvii testis et Devon, and Westsomerset, etc., London, 1841, 8vo. 



fteooxoTtog, Tiguri, 1726, 4to % — Buckland, (W.,) Archiac, (Vic. d',) and Verneuil, (Ed.de,) Me- 
Reliquiae diluvianse, or Observations on the Organic moir on the Fossils of the Older Deposits in the 

■ 

Remains attesting the Action of an Universal Deluge, Rhenish Provinces, Paris, 1842, 4to. fig. — Sand- 
London, 1826, 4to. fig. berger, (G. und Fr.,) Systematische Beschreibung 



















. 















Chap. I. 



SUCCESSION OF ANIMALS AND PLANTS. 



95 



■ 

fully appreciate, who have had a hand n 

■ 

- 

important questions still await an answer 



the 



ork 



1 



And 



even now, how many 



! 









■ 



und Abbilduns der Versteinerun<ren des Rheinischen verts des environs de Geneve, Mem. Soc. Phys., etc., 



Schichtensy stems in Nassau, Wiesbaden, 1850-54, 



4to. fig. 



For the Carboniferous period : Phillips, 
(J.,) Illustrations of the Geology of Yorkshire, Lon- 

don, 1836, 2d vol., 4to. fig. — DeKoninck, (L.,) 

Descriptions des animaux fossiles qui se trouvent 
dans le terrain houiller de la Belgique, Liege, 1842, 
2 vols. 4to. fig. ; suppl., etc. — McCoy, (Fr.,) Synop- 
sis of the Carboniferous Fossils of Ireland, Dublin, 
1844, 4to. fig. — Germar, (E. Fr.,) Die Versteine- 

des Steinkohlengebirges, Halle, 1844-53, 
Geinitz, (H. B.,) Die Versteinerungen 
der Steinkohlenformation, Leipzig, 1855, fol. fig. 
For the Permian system : Quenstedt, (A.,) Ueber 
die Identitat der Petrificate des Thuringischen und 
Englischen Zechsteins, Wiegman's Archiv, 1835, L, 

p. 75. _ Geinitz, (H. B.,) und Gutbier, (A.,) Die 

Dres- 



rungen 
fol. fig. 



Versteinerungen des Zechsteingebirges, etc., 

den, 1849, 4to. fig. — King, (W.,) Monograph of 

the Permian Fossils of England, (Palaeont. §oc.,) 

■ 

London, 1850, 4to. fig. — For the Triasic system: 
Alberti, (Fr. v.,) Beitrag zur einer Monographic 
des bunten Sandsteins, Mushelkalks, und Keupers, 
Stuttgart und Tubingen, 1834, 8vo. — For the Jura, 
Phillips, (J.,) Illustrations of the Geology of York- 
shire, York, 1829, vol. 1, 4to. fig. — Pusch, (G. G.,) 

* 

Polens Palaeontologie, etc., Stuttgart, 1836, 4to. fig 
Homer, (Fr. A.,) 



Die Versteinerungen de 



s 



nord- 



deutschen Oolithen-Gebirges, Hannover, 1836, 4to. 
fig. — Zieten, (C. H. v.,) Die Versteinerungen Wur- 



tembergs, Stuttgart, 



1830-34, fol. fig. 



Oribgny, 



(Alc. d',) Paleontologie francaise, Paris, 1840-53, 
8vo. fig. — Morris, (J.,) and Lycett, (J.,) Mollusca 
from the Great Oolite, (Pateont. Soc.,) London, 
1850-55, 4to. fig. — For the Cretaceous period: Mor- 
ton, (S. G.,) Synopsis of the Remains of the Creta- 
ceous Group of the United States, Philadelphia, 1834, 

— Orbigny, (Alc. d',) Paleont. franc., q. a. 



8vo. fig. 



Geinitz, (H. Br.,) Charakteristik der Schichten 
und Petrefakten des Kreidegebirges, Dresden, 1839- 



Pictet, (F. J.,) et Roux, (W.,) 
Description des fossiles qui se trouvent dans les gres 



42, 4to. fig 



Geneve, 1847-52, vol. 12 et 13. — Romer, (F. A.,) 

Die Versteinerungen des norddeutschen Kreidege- 



birges, 



Hannover, 1841, 4to. fig. 



Die Kreide- 



bildungen von Texas, Bonn, 1852, 4to. fig. — Reuss, 
(A. E.,) Die Versteinerungen der bohmischen Kreide- 
formation, Stuttgart, 1845-46, 4to. fig. — Muller, 
(Jos.,) Monographic der Petrefacten der Aachener 
Kreideformation, Bonn, 1851, 4to. fig. — Sharpe, 
(D.,) Fossil Remains of Mollusca found in the Chalk 
of England, (Palaeont. Soc.,) London, 1854, 4to. fig. 
Hall, (James,) Cretaceous Fossils of Nebraska, 
Trans. Amer. Acad., 1856, vol. 5. — For the Ter- 
tiaries: Brocchi, (G. B.,) Conchiologia fossile sub- 
appennina, etc., Milano, 1814-43, 2 vols., 4to. fig. 
DesHayes, (G. P.,) Description des coquilles fossiles 
des environs de Paris, 1824-37, 3 vols. 4to. Atl. 
Bronn, (H. G.,) Italiens Tertiargebilde, Heidelberg, 
1831, 8vo. — Lea, (I.,) Contributions to Geology, 

Philadelphia, 1833, 8vo. fig. — Conrad, (T. A.) 
Fossil Shells of the Tertiary Formations of North 
America, Philadelphia, 1832-36, 8vo. fig. — Grate- 
loup, (Dr.,) Conchyliologie fossile du bassin de 
l'Adour, etc., Bordeaux, 1837, 8vo. fig. — Matheron, 
(Ph.,) Catalogue methodique et descriptif des corps 



organises fossiles, etc., 



Marseilles, 1842, 8vo. 



Berendt, (G. C.,) Organische Reste im Bernstein, 
Berlin, 1845-54, fol. 



fig. 



|Wood, (S. V.,) A 

Monograph of the Crag Mollusks, (Palaeont. Soc.,) 

Edwards, (F. E.,) Eocene 



4 to. fig. 



1848-50, 

■ 

Mollusca, (Paheont. Soc.,) London, 1849-52, 4to. fig. 

Horness, (M.,) Die fossilen Mollusken des Ter- 
tiiir-Beckens von Wien, Wien, 1851, 4to. fig. 
Beyrich, (E.,) Die Conchylien des norddeutschen 
Tertiargebirges, Berlin, 1854-56, 8vo. fig.- — Tuo- 
mey, (M.,) and Holmes, (Fr. S.,) Fossils of South 
Carolina, Charleston, 1855-56, 4to. fig. 

1 Buch, (L. v.,) Petrifications recueillies en 
Amerique par Mr. Alex, de Humboldt et par Mr. 

Ch. Degenhard, Berlin, 1838, fol. fig. — Orbigny, 



■ 



Meridionale 



7 



■ 

Archiac, 












4 












! 













I 



















aTOi 






















■ »■ ■■» » 

























































































96 



ESSAY ON CLASSIFI 



Part I. 



/ 



One result, however, stands now unquestioned: the existence during each great 
geological era 1 of an assemblage of animals and plants differing essentially for each 



period. 



And by period I mean those minor subdivisions in the successive sets 



of beds of rocks, which constitute the stratified crust of our globe, the number of 



which is daily increasing, 

2 



as 



our investigations become more extensive and more 



precise. What remains to be done, is to ascertain with more and more precision, 
the true affinities of these remains to the animals and plants now living, the rela- 
tions of those of the same period to one another, and to those of the preceding 



and following 



pocl 



the precise limits of these g 



eras in the development 



of life, the character of the successive changes the animal kingdom has underg 



the special order of succession of the representat 



of each class, 3 their combina 



(Vic. d',) et Haime, (J.,) Description des animaux 



At first, only three great periods were distin- 






fossiles du groupe nummulitique de lTnde, Paris, guished, the primary, the secondary, and the tertiary ; 

Leuckart, (F. S.,) Ueber die afterwards, six or seven, (DelaBeche) ; later, from 

I ten to twelve ; now, the number is almost indefinite, 

weltlichen Schopfung, Freiburg, 1835, 4to. at least undetermined in the present stage of our 

1 Geological text-books: DelaBeche, (Sir H.T.,) knowledge, when many geologists would only con- 



1853, 4to. fig. 

Yerbreitung der ubri££ebliebenen Reste einer vor- 



Geological Manual, London, 1833, 1 vol. 8vo. ; Ger- 
man Trans, by Dechen ; French by Brochant de Vil- 
lers. — The Geological Observer, London, 1851, 8vo. 
Lyell, (Sir C.,) Manual of Elementary Geology, 
London, 1851, 1 vol. 8vo. — Principles of Geology, classes or families, are the following; Polyps and 
etc., London, 1830, 2 vols. 8vo. ; 8th edit., 1850, Infusoria: Michelin, (H.,) Iconographie Zoophy- 
1 vol. 8vo. — Naumann, (C. Fr.,) Lehrbuch der tologique, Paris, 1841-45, 4to. fig. — Edwards, (H. 



sider as subdivisions of longer periods, what some 
palaeontologists are inclined to consider as distinct 
periods. 

The principal Monographs relating to special 
s or families, are the following; Polyps and 



Geognosie, Leipzig, 1850-54, 2 vols. 8vo. Atl. 4to. 
Vogt, (C.,) Lehrbuch der Geologie und Petrefakten- 
kunde, Braunschweig, 1854, 8vo. 2 vols., 2d edit. 
Text-books on Fossils: Bronx, (H. G.,) Lethgea 



Milne,) et Haime, (J.,) Recherches, etc., q. a., p. 31. 
Polypiers fossiles des terrains paleozoiques, Arch. 
Mus., vol. 5. — Monograph of the British Fossil 
Corals, Palasont. Soc, London, 1850-55, 4to. fig. 



Geognostica, Stuttgart, 1835-37, 2 vols., 8vo. Atl. Lonsdale, (W.,) On the Corals from the Tertiary 



fol. ; 3d edit, with Fr. R^eemer, 1846, et seq. 



Formations of North America, Journ. Geol. Soc, L, 



Pictet, (F. J.,) Traite elementaire de Paleontologie, p. 495; Sill. Journ., 2d ser. IV., p. 357. — McCoy, 



etc., Paris, 1844-45, 4 vols., 8vo. fig.; 2de edit. 1853 



.) 



1 vol. 8vo. fig. 



References to all 



et seq., 8vo. Atl. 4to. — Orbigny, (Alc. d',) Cours bridge, 1854, 

elementaire de Paleontologie, Paris, 1852, 3 vols., minor papers may be found in Edwards and Haime's 



Recherches. — Ehrenberg, (C. G.,) Mikrogeologie, 
Leipzig, 1854, fol. fig. — Echinoderms : Miller, (J. 
C.,) A Natural History of the Crinoidea, Bristol, 
1821, 4to. fig. — Orbigny, (Alc. d',) Histoire 

naturelle generate et particuliere des Crinoides vivans 
English text-book of Palaeontology. A translation et fossiles, Paris, 1840, 4to. fig. — Austin, (Th. and 
of Pictet's and Bronn's works would be particularly Th. Jr.,) Monograph on Recent and Fossil Crinoidea, 
desirable. Bristol, 4to. fig. (without date.) — Hall, (J.,) 



12mo. — Giebel, (E. G.,) Fauna der Vorwelt, Leip- 
zig, 1852, 2 vols. 8vo. — Allgemeine Palasontologie, 
Leipzig, 1852, 1 vol., 8vo. — Quenstedt, (F. A.,) 
Handbuch der Petrefaktenkunde, Tubingen, 1852, 
8vo. fig. Unfortunately, there exists not a single 














li 



Chap. I. 



SUCCESSION OF ANIMALS AND PLANTS. 



97 



tions into distinct faunse during each period, not to speak of the causes, or even 
the circumstances, under which these changes may have taken 







i 



Pakeont. of New York, q. a. 

Petref. Germ., q. a. — DeKoninck, (L.,) et LeHon, 
(H.,) Recherches sur les Crinoides, etc., Bruxelles, 
1854, 4to. fig. — Owen, (D. D.,) and Shumard, (B. 
F.,) Description of New Species of Crinoidea, Journ. 



Goldfuss, (G. A.,) dermata of the British Tertiaries, (Palzeont. Soc.,) 



Ac. Nat. Sc, Philad. 1850, 4to. fig. 



SlSMONDA, 



(E.,) Monographia degli Echinidi fossili del Pie- 



monte, Torino, 1840, 4to. fig. 



DesMoulins, (C.,) 



Etude sur les Echinides, Bordeaux, 1835-37, 8vo. 
fig. — Agassiz, (L.,) Monogr. Echin., q. a., p. 54. — 
Catalogue raisonne, etc., q. a., p. 31. I quote this 
paper under my name alone, because that of Mr. 
Desor, which is added to it, has no right there. It 
was added by him, after I had left Europe, not only 
without authority, but even without my learning it, 
for a whole year. The genera Goniocidaris, Mespi- 
lia, Boletia, Lenita, Gualteria, Lovenia, Breynia, 
which bear his name, while they should bear mine, 
as I have established and named them, while Mr. 
Desor was travelling in Sweden, were appropriated 
by him, without any more right, by a mere dash of the 
pen, while he was carrying my manuscript through 
the press. How many species he has taken to him- 



self, in the same manner, I cannot tell, 
printed work, and a paper presented by me to the 
Academy of Sciences of Paris, in 1846, exhibit, for 
every one acquainted with zoological nomenclature, 
internal evidence of my statement, such, for instance, 
as my name left standing as authority for the species 
of Mespilia, Lenita, Gualteria, and Breynia, while 
the genus hears his, I need not allude further to the 
subject. This is one of the most extraordinary cases 
of plagiarism I know of. — Desor, (E.,) Synopsis des 
Echinides fossiles, Paris, 1854-56, 8vo. fig.; partly 
reprinted from my Catalogue, with additions and 
figures. — Buch, (L. v.,) Ueber die Cystideen, Ber- 
lin, 1844, 4to. fig.; Ak. d. wiss. — Muller, (J.,) 
Ueber den Bau der Echinodermen, Berlin, 1854, 4to. 

Roemek, (F.,) Ueber Stephanocrinus, etc., 



fi<°\ 



Cassel, 1851, 4to. fig. 



1852, 4to. fig.— Mem. of the Geol. Sur v. of the 
Unit. Kingdom, London, 1849, 8vo. fig., Dec. 1st, 3d, 
and 4th. — Mollushs : DesHayes, (G. P.,) Traite 
elementaire de Conchyliologie, etc., Paris, 1835-39, 

I 

2 vols. 8vo. fig. — Description des coquilles carac- 
teristique des terrains, Paris, 1831, 8vo. fig. — Wood- 
ward, (S. P.,) A Manual of the Mollusca, etc., 
London, 1851-54, 12mo. fig. — Hagenow, (Fr. v.,) 
Die Bryozoen der Maastrichter Kreideformation, 

DesMoulins, (C.,) Essai 
sur les Spherulites, Bull. Soc. Lin., Bordeaux, 1827. 
Roquan, (0. R. du,) Description des Coquilles 
fossilles de la famille des Rudistes, etc., Carcassonne, 
1841, 4to. fig. — Hoeningiiaus, (Fr. W.,) Mono- 
graphic der Gattung Crania, Dusseldorf, 1828, 4to. 

Buch, (L. v.,) Ueber Terebrateln, etc., Berlin, 
1834, 4to. fig. ; Ak. d. wiss. — Ueber Productus und 
Leptena, Berlin, 1842, 4to. fig. ; Ak. d. wiss. 
Davidson, (Th.,) British Brachiopoda, (Palaeont. 
Soc.,) London, 1851-55, 4to. fig. — DeKoninck, (L.,) 

* 

Recherches sur les animaux fossiles, Liege, 1847, 4to. 

fig. — Agassiz, (L.,) Etudes crit. q. a., p. 54. — Favre, 

As the (A.,) Observations sur les Dicerates, Geneve, 1843, 



fig. 



4to. fig. 



Bellardi, (L.,) e Michelotti, (G.,) 

Sao-o-io orittografico sulla classe dei Gasteropodi fossili, 

DeHaan, (W.,) Mono- 



Torino, 1840, 4to. fig. 



graphic Ammoniteorum et Goniatiteorum Specimen, 
Lugduni-Batav., 1825, 8vo. — Buch, (L. v.,) Ueber 
Ammoniten, iiber ihre Sonderung in Familien, etc., 
Berlin, 1832, 4to. fig. Ak. d. wiss. — Ueber Gonio- 
titen und Clymenien in Schlesien, Berlin, 1839, 4to. 
fig. ; Ak. d. wiss. — Munster, (Gr. v.,) Ueber 
Goniatiten und Planuliten im Uebergangskalk, etc., 
Baireuth, 1832, 4to. fig. — Voltz, (Ph. L.,) Obser- 
vations sur les Belemnites, Paris, 1830, 4to. fig. 

/ 

Quenstedt, (F. A.,) De Notis Nautileorum pri- 
mariis, etc., Berolini, 1834, 8vo. — Crustacea : Bron- 
gniart, (Al.,) et Desmarest, (A. G.,) Histoire 



Wiegm. Arch., 1850, p 



365. 



Monographic der naturelle des Trilohites, etc., Paris, 1822, 4to. fig. 



fossilen Crinoidenfamilie der Blastoideen, etc., Wiegm. 



Arch., 1851, p. 323. 



Forbes, (Ed.,) Echino- 

13 



Dalman, (J. W.,) Ueber die Pateaden oder die 
sogenannten Trilobiten, a. d. Schwed. , Numbers 









i 















































i 























I 







^^^^m 




. 



■ 





































■ 



. : 





























i 






98 



ESSAY ON CLASSIFICATION 



Part I 



In order to be able to compare the order of succession of the animals of past 
ages with some other prominent traits of the animal kingdom, it is necessary for 



1828, 4to. fig. — Green, (J.,) A Monograph of the of the Geol. Surv. of the United Kingdom, Dec. 6th. 



Trilobites of North America, etc., Philadelphia, 1833, 

Emmerich, (H. F.,) De Trilobitis, Bero- 



Pictet, (F. J.,) Poissons fossiles du Mt. Liban, 
Geneve, 1850, 4to. fig. — Heckel, (J. J.,) Beitrage 
lini, 1839, 8vo. fig. — Zur Naturgeschichte der Trilo- zur Kenntniss der fossilen Fische Oesterreichs, Wien, 



8vo. fig. 



biten, Meiningen, 1844, 4to. — Burmeister, (H.,) 
Die Organisation der Trilobiten, Berlin, 1843, 
4to. fig. ; (Ray Society.) — Beyrich, (E.,) Ueber 
einige bohmische Trilobiten, Berlin, 1845, 4to. ; 2d 
part, 1846, 4to. — Cord a, (A. J. C.,) und Hawle, 
(Ig.,) Prodrom einer Monographic der bohmischen 
Trilobiten, Prag, 1848, 8vo. fig. — Barrande, (J.,) 
Syst. Sil., q. a., p. 23. — Salter, (J. W.,) In Mem. 
Geol. Surv., etc., Dec. 2d. — Munster, (Gr. G. v.,) 
Beitrage zur Petrefaktenkunde, Beyreuth, 1839, 4to. 

Meyer, (H. v.,) Neue Gattungen 

De 



2d Fasc, fig. 

fossiler Krebse, etc., Stuttgart, 1840, 4to. fig. 

Koninck, (L.,) Memoire sur les Crustaces fossiles grands Sauriens, etc., Paris, 1831, 4to. fig. 



1849, 4to. fig. — Gibbes, (R. W.,) Monograph of the 
Fossil Squalid^ of the United States, Journ. Ac. Nat. 
Sc, Philadelphia, 1848 and 1849, 4to. fig.— New 
Species of Myliobates, Ibid., 1849, p. 299. — McCoy, 
(F.,) In Sedgwick and McCoy's British Palseoz. 

Rocks, q. a., p. 23. — Newberry, (J. S.,) Fishes of 
the Carbonif. Deposits of Ohio, Proc. Ac. Nat. Sc, 
Philadelphia, 1856. — Reptiles: Cuvier, (G.,) Rech. 
Oss. foss., q. a., p. 93. — Jaeger, (G. Fr.,) Ueber 
die fossilen Reptilien welche in Wurtemberg aufge- 
funden worden sind, Stuttgart, 1828, 4to. fig. — 
Geoffroy St. Hilaire, (Et.,) Recherches sur les 

Des- 



de Belgique, Liege, 1841, 4to. fig. — Cornuel, (J.,) 
Description des Entomostraces fossiles, etc., Mem. Soc. 



(E 



Mem. sur le Poecilopleuron 



Bucklandi, Caen, 1837, 4to. fig. — Bronn, (H. G.,) 

■ 

Geol. de France, 2de ser., vol. 1, part 2d, Paris, und Kaup, (J. J.,) Abhandlungen iiber die Gavial- 

Bosquet, Description des Ento- artigen Reptilien, Stuttgart, 1842, fol. fig. — Gold- 
fuss, (A.,) Der Schadelbau des Mosasaurus, N. Act. 
Ac. Nat. Car., 1844, 4to. fig. — Alton, (E. d',) und 



1846, 4to. fig. 



mostraces fossiles de la Craie de Maastricht, Mem. 
Soc. Roy. de Liege, 1847, 8vo. — Joxes, (T. R.,) 
The Entomostraca of the Cretaceous Formation of Burmeister, (H.,) Der fossile Gavial von Boll, 



England, (Paheont. Soc.,) London, 1848, 4to. fig. 
Darwin, (Ch.,) Fossil Cirripedia, (Paheont. Soc.,) 



Halle, 1854, fol. 



fig. 



Burmeister, (H.,) Die 



Labyrinthodonten, Berlin, 1850, 4to. fig. — Quen- 
London, 1851 and 1854, 4to. fig. — Insects: Brodie, stedt, (A.,) Die Mastodonsaurier sind Batrachier, 
(P. B.,) History of the Fossil Insects of the Second- Tubingen, 1850, 4to. fig. — Gibbes, (R. W.,) A 
ary Rocks of England, London, 1845, 8vo. — Heer, 

(O,) 



Mosasaurus 



Die Insektenfauna der Tertiargebilde von 



Oeningen und von Radeboy, Leipzi 






■ 

Smithson. Contrib. 1851, 4to. fig. — Meyer, (H. v.,) 
Zur Fauna der Vorwelt, Die Saurier des Muschel- 
kaikes, etc., Frankfurt a. M., 1845-52, fol. — Meyer, 

* 

Escher v. der Linth, (A.,) Zwei geologische Vor- (H. v.,) und Plieninger, (Th.,) Beitrage zur Palae- 



1853, 4to. 
fig.; N. Denk., helv. Gessellsch. — Heer, (O.,) et 



trage, etc., Zurich, 1852, 4to. — Fishes: Agassiz, 



ontologie Wiirtembergs, Stuttgart, 1844, 4to. fig. 



(L.,) Rech. s. les poiss. foss., q. a., p. 54. — Egerton, Owen, (R.,) Report on British Fossil Reptiles, Brit. 

(Sir Phil.,) A Systematic and Stratigraphical Cata- Ass. 1839, p. 43; 1841, p. 60. — Fossil Reptilia of 

logue of the Fossil Fishes, etc., London, 1837, 4to. the London Clay, (Paheont. Soc.,) London, 1849, 4to. 

2d edit. — On some new Ganoid Fishes, Proc. Geol. fig. (the Chelonia with T. Bell.) — Fossil Reptilia 

Soc. London, IV., p. 183. — On some New Species of of the Cretaceous Formation, (Palaeont. Soc.,) Lon- 






Chimseroid Fishes, Ibid., p. 153 and 2 11, and several 



don, 1851, 4to. fig. — Fossil Reptilia of the Wealden 



other papers in Trans. Geol. Soc. Lond. ; Journ. Formation, (Palaeont. Soc.,) London, 1852-55, 4to. 



Geol. Soc. ; Ann. and Mag. Nat. Hist., and Memoirs 



fig. 



Lea, (L,) On a Fossil Saurian of the New 






s 















^■M 





> 



»< S 



^^^^^^^^^■^^^^ 




• 



Chap. I. 



SUCCESSION OF ANIMALS AND PLANTS 



99 



fortunately, b 



y 



text-book of Palaeontology, arranged in zoological order 



me to make a few more remarks upon this topic. I 

brief, as we possess a 

which every one may at a glance see how, throughout all the classes of the animal 

kingdom, the different representatives of each, in past ages, are distributed 

successive geological formations 

while certain types prevail during some periods, they are entirely foreig 

This limitation is conspicuous, with 



in the 
From such a cursory survey, it must appear, that 

to others. 



reference to entire classes among Vertebrata 



while 



other typ 



relates more 



to the orders 



to the fam 



and extends 



frequently only to the g 



or the species 



But, whatever be the extent of 



their 



g 



in time, we shall see presently, that all these typ 



b 



» 

as far as 



the order of their succession is 
of living animals of the same typ 
the ( 



concerned, the closest relation to the relative rank 



compared with one another, to the ph 



of 



mbry 



growth of these typ 



m 



the present day, and even to their g 



graphical distribution upon the present surface of 



glob 



I will, however, select 



Red Sandstone, etc., Philadelphia, 1852, 4to. fig. 
Leidy, (Jos.,) Description of Extinct Mammalia and 
Chelonia from Nebraska Territory, in D. D. Owen, 
Geol. Surv. of Wisconsin, Iowa, Minesota, etc., 
Philadelphia, 1852, 4to. fig. — On Bathygnathus 
borealis, an extinct Saurian, Journ. Ac. Nat. Sc, 
Philad., 1854, 4to. fig. — Description of a New Species 
of Crocodile, etc., Ibid., 1851. — Birds: Owen, (R.,) 

■ 

History of British Fossil Mammalia and Birds, Lon- 
don, 1844-46, 1 vol. 8vo. fig. — Fossil Birds from the 



Schmerling, (P. C.,) Recherches sur les ossemens 
fossiles des cavernes de Liege, Liege, 1833-36, 



2 vols. 4to. fig. 



Croizet et Jobert, Recherches 
sur les ossemens fossiles du departement du Puy-de- 
Dome, Paris, 1828, fol. fig. — Meyer, (H. v.,) Zur 



Fauna, etc., q. a, 



Die fossilen Zahrie und Knochen, 



in der Gegend von Georgensgmund, Frankfurt a. M., 



1834, 



4to. fig. 



Jaeger, (G. Fr.,) Die fossilen 



Saugethiere Wiirtembergs, Stuttgardt, 1835-39, fol. 

Falconer, (H.,) and Cautley, (P. T.,) 



fig. 



Wealden 



Memoir on 



- 

the Dinornis, Trans. Zool. Soc, vol. 3, p. 3, London 
1844, 4to. fig. — Mammalia : Cuvier, (G.,) Oss. foss. 



Fauna antiqua sivalensis, etc., London, 1846, fol. fig. 
Gervais, (P.,) Zoologie et Paleontologie franr 



caises, Paris, 



1848-52, 4to. fig. 



MULLER, (J.,) 



q. a 



(W 



,94. 



DeBlainville, (Ducr.,) Osteographie ou Descrip- 
tion iconographique comparee du Squelette, etc., 
Paris, 1841, et suiv. 4to., Atlas fol. — Kaup, (J. J.,) 
Descriptions d'ossemens fossiles de Mammiferes incon- 

Owen, (R.,). 

Odontography, or a Treatise on the Comparative 
Anatomy of the Teeth, London, 1840-41, 3 vols. 8vo. 



nus, Darmstadt, 1832-39, 4to. fig. 



fig. 



Brit. foss. Mam. and Birds, q. a, 



The Fossil 



Mammalia of the Voyage of H. M, S. Beagle, 
London, 1838, 4to. fig. — Description of the Skeleton 
of an extinct gigantic Sloth, Mylodon robustus, Lon- 
don, 1842, 4to. fig.; and many papers in Journal 
of Geological Society ; Trans. Zool. Society, etc. 



Ueber die fossilen Reste der Zeuglodonten, etc., 
Berlin, 1849, fol. fig. — LeConte, (J.,) On Platy- 
gonus compressus, Mem. Amer. Acad. Arts and Sc, 
1848, 4to. fig. — Wyman, (J.,) Notice of the Geo- 
logical Position of Castoroides ohioensis, by J. Hall, 
and an Anatomical Description of the same, Boston 
Journ. Nat. Hist., 1847, vol. 5, p. 385, 8vo. fig. 
"Warren, (J. C.,) Description of a Skeleton of the 
Mastodon giganteus, Boston, 1852, 4to. fol. — Leidy, 
(J.,) The Ancient Fauna of Nebraska, Smith. Contr., 



Wash 



See also Sect. 22. 



I allude to the classical work of Pictet, Traite 
elementaire de Paleontologie, q. a., a second edition 
of which is now publishing. 

















i 














i 



i 
























* 




■ 








^fc 











































'. 


























p I 











fe 


















100 



ESSAY ON CLASSIFICATION 



Part I, 



■ 



a few examples for further discussion. Among Echinoderms the Crinoids are, for 
a long succession of periods, the only representatives of that class; next follow 



the 



Starfishes, and next the Sea-Urchins, the oldest of which belong to the type 



of Cidaris and Echinus, followed by Clypeastroids and Spatangoids. No satisfactory 
evidence of the existence of Holothuriae has yet been found. Among Crustacea, 

irison of the splendid work of Barrande 1 upon the Silurian System of 



a 



comp 



Bohemia, with the paper of Count Miinster upon the Crustacea of Solenhofen, 2 and 
with the work of Desmarest upon fossil Crabs, 3 will at once show that while 
Trilobites are the only Crustacea of the oldest palaeozoic rocks, there is found in 
the Jurassic period a carcinological fauna entirely composed of Macrura, to which 



Brachy 



are added in the tertiary period. The formations intermediate between 



the older palaeozoic rocks and the Jura contain the remains of other Entomostraca, 
and later of some Macroura also. In both classes the succession of their repre- 
sentatives, in different periods, agrees with their respective standing, as determined 
by the gradation of their structure. 

Among plants, we find in the Carboniferous period prominently, Ferns and 



- 

in the Triassic period Equisetaceae 5 and Coniferse prevail 



Lycopodiaceae ; 4 1 

Jurassic deposits, Cycadeae, 6 and Monocotyledoneae ; while later 



m 



the 



Dicotyledoneae 



8 



take the lead. 7 The iconographic illustration of the vegetation of past ages has 

- 

of late advanced beyond the attempts to represent the characteristic features of 

the animal world in different geological periods. 

Without attempting here to characterize this order of succession, this much follows 
already from the facts mentioned, that while the material world is ever the same 



through all ages in 



all its combinations, as far back as direct 



g 



can 



trace its existence, organized beings, on the contrary, transform these same mate- 
rials into ever new forms and new combinations. The carbonate of lime of all 



ages is the same carbonate of lime in form as well as composit 



as 



g as it 




is under the action of physical 



g 



nly 



Let life be introduced upon earth 



. 23. 



■ 

1 Barrande's Syst. Silur., q, a., p 

2 Gr. G. y. Munster, Beitrage zur Petrefacten 
kunde, q. a., p. 98. 



of Plants found in the Oolite, etc., Trans, Geol. Soc, 
Lond. 2d ser. IL, p. 395. 

1 Unger, (Fr.,) Chloris protogsea, Beitrage zur 



3 Desmarest, see Brongniart and Desinarest's Flora der Vorwelt, Leipzig, 1841, 4to. fig. — Heer, 



(O.,) Flora tertiaria Helvetian, Wintherthur, 1855, 



fol. fig. 



Hist. Nat. d. Tril. et Crust., q. a., p. 97. 

4 See, above, p. 93. 

6 Schimper, (W. P.,) et Mougeot, (A.,) Mono- ,8 Landscapes of the different geological periods 

graphie des Plantes Fossiles du Gres-bigarre de la are represented in Unger, (Fr.,) Die Vorwelt in 

chaine des Vosges, Strasb. et Paris, 1840-43, 4to. ihren vershiedenen Bildungsperioden, Wien, fol. (no 

fisr. date.) These landscapes are ideal representations of 



g- 



6 Buckland, (W.,) On the Cycadeoidae, a Family the vegetation >of p&st ages. 



. , 





\ 



■■1 













Chap. I. 



SUCCESSION OF ANIMALS AND PLANTS 



101 



and 



Polyp builds its coral out of it, and each family, each genus, each species 
a different one and different ones for all successive geological epochs. Phosphate 

- 

the same phosphate, as when prepared artificially by 



of lime in palaeozoic rocks is 
Man; but a Fish makes its spines 



out of it, and every Fish in its own way. 



a 



Turtle its shield, a 



Bird its wings, a Quadruped its legs, and Man, like all other 



Vertebrates, its whole skeleton, and during each successive period in the history 
of our globe, these structures are different for different species. What similarity is 
there between these facts! Do they not plainly indicate the working of different 
agencies excluding one another? Truly the noble frame of Man does not owe its 

origin to the same 

And what is 

stances ; they present the same 



forces which combine to give a definite shape to the crystal, 
true of the carbonate of lime, is equally true of all inorganic sub- 

characters in all ages past, as those they exhibit now. 



Let us look upon the subject in 



still another light, and we shall see that the 



same is also true of the influence of all physical causes. Among these agents, the 
most powerful is certainly electricity ; the only one to which, though erroneously, the 

been directly ascribed. The effects it may now 

them in the same manner. It has 

deposited them in crystalline 



formation of animals has ever 

produce, it has always produced, and produced 

reduced metallic ores and various 
form, in veins, during all 



earthy mineral 



s and 



geological ages; it has transported these and other 

ii ;~ +; moa r>nst,. as we mav do now in our 



substances from one point to another, in times past, as we may 



laboratories, under its influence. 



Evaporation upon the surface of the earth has 



■ 

always produced clouds in 



the atmosphere, w 



■_ . 



condensed in rain showers in past ages as now 



ous and triassic rocks have brought to us 

■ 

operation of physical agents in past ages, 



hich after accumulating have been 

Rain drop marks in the carbonifer- 

this testimony of the identity of the 

to remind us that what these agents may 



do now, they already did in the same way, in 
done at all times. Who could, in presence 

s 

nection between two series of phenomena, 



the oldest geological times, and have 
of such facts, assume any causal con- 



the one of which is ever obeying the 



same 



laws, while the other presents at every successive period new relations, an 

combinations, leading to a final climax with the 

on the contrary, that this identity of the 

totally disproves any influence on their part 

changing beings, which constitute the organic world, 



■ 

ever changing gradation of new 
appearance of Man? Who does not see, 
products of physical agents in all ages 



in the production of these ever 
and which exhibit, as a 



whole such striking evidence of connected thoughts! 






I 










II 















I 



■ 






: » 










rtPa 










.. 










































102 



ESSAY ON CLASSIFICATION. 



Part I. 



SECTION XXII. 







































LOCALIZATION OF TYPES IN PAST AGES. 



The 



study of the geographical distribution of the animals now living upon 
earth has taught us, that every species of animals and plants has a fixed home, and 



even that peculiar typ 



may 



b 



circumscribed within definite limits, upon the 



surface of our 



globe 



But it is 




tly, since geological 



g 



have 



been carried on in remote parts of the world, that it has been ascertained that 
this special localization of types extends to past ages. Lund for the first time 
showed that the extinct Fauna of the Brazils, 1 during the latest period of a past 
age, consists of different representatives of the very same types now prevalent in 
that continent; Owen has observed similar relations between the extinct Fauna 
of Australia 2 and the types now living upon that continent. 

If there is any naturalist left who believes that the F 
may be derived from another portion of the globe, the study of these facts, in 
all their bearing, may undeceive 



of one continent 



It is 



3 him. 
well known how characteristic the Edentata are for the present Fauna 



of the Brazils, for there is the home of the Sloths, (Bradyp 



(Dasypus,) the Antreaters, (Myrmecophag; 



there also have b 



the Tatous, 
found those 



traordinary extinct g 



the Megatherium, the Mylodon, the Megalony 



the 



Glyptodon, and the many other g 



described by Dr. Lund and Professor 



Owen 



all of which belong to this same order of Edentata 



Some of these 



of Edentata had also representatives in North America, during the 



extinctl genera I 

same geological period, 8 thus showing that though limited within similar 
range of this type has been different in different epochs. 



the 



Australia, at present almost exclusively the home of Marsupials, has yielded 



also a considerable number of equally remarkable species, and two extinct g 



of that type, all described by Owen in 



a 



port to the British Associat 



in 



1844, and in Michell's Expeditions into the Interior of Australia 














. 




1 



Lund, (Dr.,) Blik paa Brasiliens Dyreverden of Extinct Mammalia, Ann. and Mag. Nat. Hist., 1846, 



for sidste Jordomvseltning. K. Danske Vidensk. vol. 17, p. 197. 
Selsk. Afhandl. VIII., Kiobenhavn, 1841, 4to. fig., p. 



3 



) A Memoir 



61, etc. ; Engl. Abstract, Ann. and Mag. vol. 3, p. Tribe of North America, Smithson. Contrib. 1855, 4to. 



422. 



fig. 



Wyman, (J.,) Notice of Fossil Bones, etc., Am 



2 Owen, (B,,) On the Geographical Distribution Journ. Sc. and A., 2d ser., 1850, vol. 10. 






s 









.' 




























Chap. I. 



EAKLY LOCALIZATION OF TYPES 



103 






How far similar facts are likely to occur in other classes, remains to b 



ascer- 



tained 







knowledg 



of the geographical distribution of the fossil remains is 



It is, however 



yet too fragmentary to furnish any further data upon this point. 

the types of the oldest geological periods had a 

much" wider distribution than most recent families exhibit now, some families of 



worthy of remark, that though 



fishes largely represented in the Devonian 



ystem of the Old World have not 






yet been noticed among 

the Cephalaspids, the Dipt 

Reptiles of the Triasic and Oolitic periods 



the fossils of that period in America, as, for instance, 



and the Acanthodi 



Ag 



of the many gig 



none are known to occur elsewhere 



pt in Europ 



and it can hardly be simply 



g 



to the less extensive dis 



tribution of these formations in other par 

the same formations are 



of the world, since other fossils of 



known from other continents. It is more likely that 
some of them, at least, are peculiar to limited areas of the surface of the globe, 



as, even in Europe, 
Without, however 



their distribution is not extensive. 



g upon 



debatable ground, it remains evident, that 



before the establishment of the present state of things, pecul 
which were formerly circumscribed with 



tyP 



of 



* 

mals 



definite limits, have continued to occupy 



the same or similar grounds in 



the present period, even though nog 



con- 



be assumed between them, their representatives 



these different forma 



■ 

■ 

tions not even belonging to the same genera. 

assumption that physical 



contradiction with any 

do with their origin; for though 

might at first seem to favor such a view, 



their 



Such facts are in the most direct 

i * 

igents could have any thing to 
within similar geographical areas 
it must be borne in mind that these 



localized being 



associated with other typ 



which have a much wider 



g 



and, what is still more significant 



between which 



g 



physical chang 



facts indicate precisely the reverse 
continued similarity of organized bein 

■ 

withstanding the extensive chang 



they belong to different geological periods, 
have undoubtedly taken place. Thus the 
of what the theory assumes; they prove a 



6 



durin 



o 



successive geological periods, not- 



the prevailing 



physical conditions, which the 



untry they inhabited may have undergone, at different periods 



In whatever direc 



theory of the origin of 



animals and plants, under the influence of physical 



agents, is approached 



can 



nowhere stand a critical examination. Only 



delib 



erate intervention of an Intellect, ac 
account for phenomena of this kind 



g 



ly, according to 



one 




can 






























! 

























I 


















I 



I 







•' 










^ 












- 














^ 









I : 









, i 



104 



ESSAY ON CLASSIFICATION 



Part I. 









I 






















































SECTION XXIII. 



LIMITATION OF SPECIES TO PARTICULAR GEOLOGICAL PERIODS. 



Without entering into a discussion respecting the precise limits within which this 

fact is true, there can no longer be any doubt, that not only species, but all other 



groups of animals and plant 



have 



definite range of duration 



well as individ- 



uals 



i 



The limits of this duration, as far as species are concerned, generally coin- 



changes in the physical conditions of the, earth's surface; 2 though, 
most of those investigators who would ascribe the origin of organ- 



3 



cide with grea 
strange to say 
ized beings to the influence of such causes, maintain also, that species may extend 

from one period to another, which implies that these are not affected by such 

changes 

When considering, in general, the limitation of species to particular geological 

* 

periods, we might very properly disregard the question of the simultaneity of the 
successive appearance and disappearance 
result of the investigation^ as long as it 



of Faunas, as in no way affecting the 
is universally conceded, that there is no 
species, known among the fossils, which extends through an indefinite series of 
geological formations. Moreover, the number of the species, still considered as 



identical in several successive periods 



g 



smaller and smaller 



g 



in proportion 
>, how widely 
considered as identical with living ones, differ 
from them, 4 and also how different the species of the same family may be, in 



as they are more closely compared. I have already shown, long 
many of the 




species 



Ion 



successive subdivisions of the same g 
the same result in his investigations 



at geological formation. Hall has come to 
of the fossils of the State of New York. 6 



- 

Every monograph reduces their number, in every formation. Thus Barrande, who 
has devoted so many years 



to the most minute investigation of the Trilobite 



of 
















1 Compare Sect. XIX. 



Paris, 1850, 2 vols. 12mo. — Morris, (J.,) Catalogue 



2 Elie de Beaumon.t, Recherches sur quelques- of the British Fossils, London, 1854, 1 vol. 8vo. 



4 Agassiz, (L.,) Coquilles tertiaires reputees 
identiques avec les especes vivantes, Neuchatel, 1845, 



■ 

unes des Revolutions de la surface du Globe, Paris, 
1830, 1 vol. 8vo. 

8 For indications respecting the occurrence of all 
species of fossil organized beings now known, consult, 5 Agassiz, (L.,) Etudes critiques sur 

Bronn, (H. G.,) Index palseontologicus, Stuttgardt, ques fossiles, Neuchatel, 1840-45, 4to. fig. 



4to. fig. 



Mollus- 



1848-49, 3 vols. 8vo. — Orbigny, (A. d',) Prodrome 



6 Hall, (J.,) Palaeontology of the State of New 



de Paleontologie stratigraphique universelle etc., York, q. a., p. 23, note 1 




■ ■ - 







Mi 









Chap. I. 



LIMITATION OF SPECIES IN TIME. 



105 



■ 

Bohemia 1 has come to the conclusion that their species do not extend from one 
formation to the other- D'Orbigny 2 &nd Pictet 3 have come to the same conclusion 
for the fossil remains of all classes. It may well be said that, as fossil remains 
are studied more carefully, in a zoological point of view, the supposed identity of 



in different geological 



formations, vanishes gradually more and more ; so 



sp e cie s, I 

■ 

that the limitation of species in 

earlier investigations of their remains in successive 

scribed, step by step, within narrower, more definite, and also more equable periods. 

Species are truly limited in time, as they are limited in space, upon the surface of 



time, already ascertained in a general way, by the 

geological formations, is circum- 



the globe. 



The facts do not exhibit a gradual disappearance of a limited number of 



species, and an equally gradual introduction of. an equally limited number of new 
ones ; but, on the contrary, the simultaneous creation and the simultaneous destruc- 
tion of entire faunse, and a coincidence between 



these changes in the 



organic world 



and the great physical changes our earth has undergone. Yet it would be premature 



the geographical range 



of these changes, and 



to attempt to determine the extent of 

still more questionable to assert their synchronism upon the whole surface of the 
globe, in the ocean and upon dry land. 



To form adequate ideas of the great physical 



changes 



the surface of our globe 



has undergone, and the frequency of these modifications of the character of the 
earth's surface, and of their coincidence with the changes observed among the organ- 
ized beings, it is necessary to study attentively the works of Elie de Beaumont. 4 
He, for the first time, attempted to determine the 



relative age 



of the different sys- 
terns of mountains, and showed first, also, that the physical disturbances occasioned 
by their upheaval coincided with the successive disappearance of entire faunae, and 

In his earlier papers he recognized seven, then 



the 



reappearance 



of 



new ones. 



twelve, afterwards fifteen such great convulsions of the globe, and now 



he has 



traced 



more or 



less fully and conclusively the evidence that the number of these 



disturbances has been at least sixty, perhaps one 



hundred. But while the genesis 



,' 



and genealogy of our mountain systems were thus illustrated, palaeontologists, extend- 
between the fossils of different formations more carefully to 



mg 



their 



comparisons 



marked 



all the successive beds of each great era, have observed more and more 
differences between them, and satisfied themselves that faunae also have been more 
frequently renovated, than was formerly supposed; so that the general results of 



1 Barrande, Systeme silurien, etc., q. a. ; see 



Mono 



Systeme silurien, etc., q. a. ; se 
t/phies d'Echinodermes, q. a., p. 54. 
, Paleontologie Francaise, a. a., d. 9« 



8 



D'Orbigny, Paleontologie Franchise, q. a., p. 95 
Pictet, Traits de Paleontologie, etc., q. a., p 



96, note 1. 



4 Elie de Beaumont, Notice sur les systemes de 
Montagnes, Paris, 1852, 3 vols. 12mo. ; see, also, 
Buch, (Leop. v.,) Ueber die geognotischen Systeme 
von Deutschland, Leonhard's Taschenb., 1824, II., p. 

501. 



14 






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: t 








































106 



ESSAY ON CLASSIFICATION 



Part I 










1 













































i 


























geology proper and of palaeontology concur in the main to prove, that while the 



globe has been at repeated intervals, and indeed frequently, though after immensely 
long periods, altered and altered again, until it has assumed its present condition, 
so have also animals and plants, living upon its surface, been again and again extin- 
guished and replaced by others, until those now living were called into existence 

* 

with man at their head. The investigation is not in every case sufficiently com- 
plete to show evervwhere a coincidence between this renovation of animals and 

plants and the gr< 

* 

the globe, but it is already extensive enough to exhibit a frequent synchronism and 

in the end, lead to a com- 



ywhere a coincidence between this renovation of animals ai 
at physical revolutions which have altered the general aspect of 



correlation, and to warrant the expectation that it will 
plete demonstration of their mutual dependence, not as 



and effect, but 



step 



as 



the same prog 
the organic m 



development of a plan which embraces the physical as well 



orld 



In order not to misapprehend the facts, and perhaps to fall back upon the 
idea, that these changes may be the cause of the differences observed between the 
fossils of different periods, it must be well understood that, while organized beings 

+ 

exhibit through all geological formations a regular order of succession, the character 
of which will be more fully illustrated hereafter, this succession has been from 
time to time violently interrupted by physical disturbances, without any of these 

* 

altering in any way the progressive 



character of that succession of organized being 



Truly this shows that the important, the leading feature of this whole drama 



is 



the development of life, 1 and that the material world affords only the elements for 



its realization. The simultaneous disapp 



of entire faunas, and the following 






simultaneous appearance of other faunas, show further that, as all these faunae com 



sist of the g 



variety of types, 2 in all formations, combined 



■where into 



natural associations of animals and plants, between which there have been definite 



relations at all times, their 



g 



can at no time be 



g to the limited influence 



of monotonous physical causes, ever acting in the same way. Here, again, the 
intervention of a Creator is displayed in the most striking manner, in every stage 
of the history of the world. 



1 Dana,- (J. D.,) Address, q. a., p. 94, note 1 



2 Agassiz, (L.,) Geol. Times, q. a., p. 25. 













i 





























Chap. I. 



SUCCESSION AND STANDING OF ANIMALS 



107 






SECTION XXIV. 






PARALLELISM BETWEEN THE GEOLOGICAL SUCCESSION OF ANIMALS AND PLANTS AND 



THEIR PRESENT RELATIVE STANDING. 



The total absence of the highest representativ 



of the animal kingdom 



the 



oldest deposits forming part of the crnst of onr globe, has naturally led to the 
very general belief, that the animals which have existed during the earliest period 
of the history of our earth were inferior to those now living, nay, that there is 

exist- 



a 



natural gradation from the oldest and lowest animals to the highest now 



ence. 



i 



To some extent this is true: but it is 



ly not true that all animals 



form one simple series 



from the earliest times, during which only the lowest typ 



of animals would have been represented, to the last period, when Man appeared 



at the head of the animal creation. 



2 



It has 



dy been shown 




VII.) that 



presentatives of all the g 



tyP 



of the animal kingdom have existed from the 



beginning of the creation of organized being 



■ 

It is therefore not in the succes- 



sive appearance of the g 



branches of the animal kingdom, that we may expect 






to trace a 



parallelism between their succession in geological times and their relative 

„,„o» ™m^«nmirlence be observed between the 



standing at present. Nor can any 



such 



ponden 



appearance of classes 



least not among 



ipective classes seem to have been 



perhaps the sole 



pt 



Radiata, Mollusks, and Articulata, as their 

duced simultaneously upon our earth, with 

of the Insects, which are not known to have existed 



before the Carboniferous period. Among Vertebrata, however, there appears already a 
certain coincidence, even within the limits of the classes, between the time of their 
introduction, and the rank their representatives hold, in comparison to one another. 

But 



upon this point more hereafter 



It 



nly within the limits of the different orders of each class, that the paral- 



lelism between the succession of their 



presentatives in past 



tive rank 



must be at the same 



the present period 



decidedly charactenst 



ges and their respec 
But if this is true, it 

* 



time obvious to what extent the recognition of this corre- 

fluenced by the state of our knowledge of the true affinities 

and natural gradation of living animals, and that until our classifications have become 



ipondence may be 



expression 



of these natural relations, 



the correct 

withMthe su 

On that account it would be presumptu 



the most striking; coincidence 



to 



of their representatives in past ages may be entirely overlooked. 

»us on my part to pretend, that I could 













! 





















' 















See the palseontological works quoted in Sect. 21. 



2 Agassiz, (L.,) Twelve Leek, etc., p. 25 and 69. 
































108 



ESSAY ON CLASSIFICATION. 



Part I. 











































illustrate this proposition, through the whole animal 

would involve the assertion that I know all these relations, or that where there 



kingdom, as such an attempt 



exists a discrepancy between the classification and the succession of animal 



the 



classificatio 



must be incorrect, or the 



tionship of the fossils incorrectly appre 



ciated 



I shall therefore limit myself here to a g 



comp 



which may 



however, be sufficient to show, that the improvements which have been introduced 
in our systems, upon purely zoological grounds, have nevertheless tended to render 
more apparent the coincidence between the relative standing among living animals 
and the order of succession of their representatives in past ages. I have lately 

■ 

attempted to show, that the order of Halcyonoids, among Polyps, is superior to that 
of Actinoids ; 1 that, in this class, compound communities constitute a higher degree of 

1 * 

1 

development, when contrasted with the characters and mode of existence of single 
Polyps, as exhibited by the Actinia; that top-budding is superior to lateral budding; 
and that the type of Madrepores, with their top-animal, or at least with a defi- 
nite and limited number of tentacles, is superior to all other Actinoids. If this be 
so, the prevalence of Actinoids in older geological formations, to the exclusion of 

- 

Halcyonoids, the prevalence of Mucosa and Tabulata in the oldest deposits, 2 the 
later prevalence of Astraeoids, and the very late introduction of Madrepores, would 
already exhibit a correspondence between the rank of the living Polyps and the 

- ■ 

representatives of that class in past ages, though we may hardly expect a very close 
coincidence in this respect between animals the structure of which is so simple. 
The gradation among the orders of Echinoderms is perfectly plain. Lowest 
stand the Crinoids, next the Asterioids, next the Echinoids, and highest the Holo- 
thurioids. Ever since this class has been circumscribed within its natural limits, 
this succession has been considered as expressing their natural relative standing, and 
modern investigations respecting their anatomy and embryology, however extensive, 
have not led to any important change in their classification, as far as the estimation 

* 

■ 

of their rank is concerned. This is also precisely the order in which the representa- 
tives of this class have successively been introduced upon earth in past geological ages. 

5 only, and this order 
of successive periods: next come free Crinoids 



Among the oldest formations we find pedunculated Cinoids 



remains prominent for 



series 



Asterioids; next Echinoids, 4 the successive appearance of which since the triasic 









■ 

1 For classification of Polypi, see Dana, q. a., p. 
31, note 2 ; also Milne-Edwards and Haime, q. a. 
and Agassiz, (L.,) Classification of Polyps, Proc 
Am. Acad. Sc. and Arts, 1856, p. 187. 

2 See Milne-Edwards and Haime, q. a., p. 31 

3 Miller, Crinoids, q. a. — D'Orbigny, q. a. 

■ 

J. Hall, q. a. — Austin, q. a., p. 96. 



— 

4 See the works q. a., p. 96 ; also : Muller, (J.,) 

■ 

and Troschel, (F. H.,) System der Asteriden, 
Braunschweig, 1842, 4to. fig. — Muller, (J.,) Ueber 



Tie- 



den Bau der Echinodermen, Berlin, 1854, 4to.— 
deman, (Fr.,) Anatomie der Rohren-Holothurie, des 
Seeigels, etc., Landshut, 1817, fol. fig. — Valentin, 
(G.,) Anat. du gerne Echinus, Neuchatel, 1842, 4to. 

































\ 



Chap. I. 



SUCCESSION AND STANDING OF ANIMALS 



109 



period to the present day, coincides also with the gradation of their subdivisions, 
as determined by their structure ; and it was not until the present period, that the 
highest Echinoderms, the Holothurioids, have assumed a prominent position in their 

class. 

not any more uncertainty respecting the relative rank 



Among Acephala there is 



of their living representatives, than 



among 



Echinoderms 



Every 



g 



- 

acknowl 



edges the inferiority of the Bry 



and the Brachiopods 1 when compared with the 



Lamellibranchiata, and among 



these the inferiority of the Monomyaria in comp 



son with the Dimyaria would hardly be denied 



Now if any fact is well established 



m 



Paige ontolog 



the earlier appearance and prevalence of Bry 



and B 



chiopods in the oldest geological formations, and their extraordinary development 






for a long succession of ages, until 

they maintain to the fullest extent at present 



Lamellibranchiata assume the 



ndency which 



A closer comparison of the differ 



ent 



families of these orders might further 



show how close this 



ipondence 



through all ages. 

Of Gasteropoda I have nothing special 

how imperfectly their remains have been : 

been done for the fossils of other classes. 



to say, as every palaeontologist is aware 

Lvestigated in comparison with what has 

Yet the Pulmonata are known to be 



Branchifera, and among these the Siphonostomata 
to have appeared Fater than the Holostomata, and this exhibits already a general 



of more recent origin than the 



coincidence between their succession in 



time and their respectiv 



rank 



Our present knowledg 



of the anatomy of the Nautilus, for which science is 



indebted to the skill of Owen, 2 may satisfy evei 
Tetrabranchiata are inferior to the Dibranchiata 



ybody that among Cephalopods the 

it is not too much to say, 



and 



that one of the first points a 



collector of fossils may ascertain for himself, 



the 



exclusive prevalence of the representatives of the first of these ^ types in the oldest 
formations, and the later appearance, about the middle 
atives of the other type, which at present is 

said of importa 



Of Worms, nothing can b 



gical ages, of represent 
the most widely distributed. 

with reference to our inquiry 



1 Orbigny, (A. d',) Bryozoires, Ann. Sc. Nat., 3e 
ser. 1851, vol. 16, p. 292.— Cuvier, (G.,) Memoire 
sur Fanimal cle la Lingule, Ann. Mus. L, p. 69, fig. 
Vogt, (C.,) Anatomie der Lingula anatina, N. Mem. 

* 

Soc. Helv. 1843, VII.,4to. fig. — Owen, (R.,) On the 



Anatomy of the Brachiopoda, Trans. Zool. Soc, J. 

4to., p. 145, fig.— On the Anatomy of the Terebratula, 

1853, 4to. fig. (PaJaeont. Soc.)— Buch, (L. v.,) Ueber r _ 

Terebrateln, q. a., p. 97—Davidson, (Th.,) Monogr. eages, (Ak. de,) et Blanchaud, (Em.) Voyage en 

etc., q. a., p. 97. -Poli (Xay.,) Testacea utriusqne Sicile, Paris, 3 vols. 4to. fig. (without date.) 



■ 

* 

Sicilian eorumque Historia et Anatomia, Parm^e, 
1791-93, 2 vols. fol. fig., continued by Delle Chiaje. 

2 Owen, (R.,) Memoir on the Pearly Nautilus, 
London, 1832, 4to. fig. — Valenciennes, (A.,) Nou- 
velles Recherches anatomiques sur le Nautile. C. R.« 
Paris, 1841, 4to. — Cuvier, 

servir a l'Histoire et a l'Anatomie des Mollusques, 
Paris, 1 8 1 7, 4to. fig. 



Mem 



M.,) Q 
















II 



i| 





















, . 






> i 









■ 


















li 
















■*fc _ 'J I 



■■■■ 










( 























110 



ESSAY ON CLASSIFICATION. 



Part I. 








































but the Crustacea exhibit 



g 



the most striking coincidence. Without 



g 



into details, it appears from the classification of Milne-Edwards that Decapods, Sto- 
mapods, Amphipods, and Isopods constitute the higher orders, while Branchiopods, 
Entomostraca, Trilobites, and the parasitic types, constitute, with Limulus, the lower 



orders of this class. 



1 



In the classification of D 



2 



his first type embraces D 



pods and Stomapods, the second Amphipods and Isopods, the third Entomostraca, 
including Branchiopods, the fourth Cirripedia, and the fifth Botatoria. Both acknowl- 
edge in the main the same gradation ; though they differ greatly in the combina- 
tion of the leading groups, and also the exclusion by Milne-Edwards of some types, 



as the Botifera, which Burmeister first, then D 



and 



Leydig, unite 



justly 



as 



I 



believe, with the Crustacea. 3 This gradation now presents the most perfect coinci- 
dence with the order of succession of Crustacea in past geological ages, even down 

- 

to their subdivisions into minor groups. Trilobites and Entomostraca are the only 



presentat 



of the class in palaeozoic rocks 



the middle geological ag 



appear 



a 



•iety of Shrimb, among which the Macrouran Decapods are prominent, and later 



only the Brachy 



which are the most 



numer 



in our day 



The fragmentary knowledge we possess of the fossil Insects, does not justify 
us, yet, in expecting to ascertain with any degree of precision, the character of 
their succession through all geological formations, though much valuable information 
has already been obtained respecting the entomological faunae of several geological 

periods 

The order of succession of Vertebrata in past ages, exhibits features in many 

* 

respects differing greatly from the Articulata, Mollusks, and Radiata. Among these 



we find their respective classes appearing simultaneously in the oldest periods of 



4 



the history of our earth. Not so with the Vertebrata, for though Fishes may be 
as old as any of the lower classes, Reptiles, Birds, and Mammalia are introduced 

tin, the earliest 



ccessively in the order of their relative rank in their typ 



Ag 



presentatives of these classes do not always seem to be the lowest; on the con- 



trary 



they are to a certain extent, and in a certain sense, the highest, in as far 



as they embody characters, which, in later periods, appear separately in higher 

Sect. 26,) to the exclusion of what henceforth constitutes the special 



classes 




■ .... L 




character of the lower class. For instance, the oldest Fishes known partake of 
the characters, which, at a later time, are exclusively found in Reptiles, and no 
longer belong to the Fishes of the present day. It may be said, that the earliest 
Fishes are rather the oldest representatives of the type of Vertebrata than of the 







Milne 



Hist. Nat. des Crustaces, 



Paris, 1834-40, 3 vols. 8vo. 

2 Dana, (J. D.,) Crustacea, q. a., p. 32. 



3 Leydig, (Fr.,) Raderthiere, etc., Zeitsch. f. 
wiss. Zool. 1854, vol. 6, p. 1. 



„_ _ 7 „ — 7 J. 

4 Heer, q. a. ; Brodie, q. a., p. 98. 








. 





\ 



s 






I 






Chap. I. 



SUCCESSION AND STANDING OF ANIMALS. 



Ill 



class of Fishes, and that this class assumes only its proper characters after the 
introduction of the class of Reptiles upon earth. Similar relations may be traced 
between the Reptiles and the classes of Birds and Mammalia, which they precede. 
I need only allude here to the resemblance of the Pterodactyli and the Birds, and 
to that of Ichthyosauri and certain Cetacea. 
tions, there runs an evident tendency 



Yet, through all these intricate rela- 



towards the production of higher and higher 



types, until at last, Man crowns 



the whole series. 



Seen 



as 



it were at a distance, 



so that the mind can take a general survey of the whole, and perceive the con- 
nection of the successive steps, without being bewildered by the details, such a 
series appears like the development of a great conception, expressed in such har- 



monious 



proportions, that every link appears necessary to the full comprehension 



of its meaning, and yet, so 



independent and perfect 



in itself, that it might be 



mistaken for a complete whole, and again, so intimately connected with the pre- 

the series, that one might be viewed as flowing 
What is universally acknowledged as characteristic of the highest 
conceptions of genius, is here displayed in a fulness, a richness, a magnificence, 



ceding and following members of 
out of the other. 



an amplitude, a perfection of details, a 



complication of relations, which baffle our 



skill and our most persevering 



efforts to appreciate all its beauties. 



Who 



can 



look upon such series, coinciding to 



such an extent, and not read in them the 



successive manifestations of a thought, expressed at different times, in ever new 

end onwards to the coming of Man, whose 



forms, and yet tending to the same 



advent is already prophesied in 

The relative standing of plants 
of animals. Their great types are 
structure ; they exhibit, therefore, a more 
their highest types, which are not 
animals are in Man. 



the first appearance of the earliest Fishes! 

* 

presents a somewhat different character from that 
not built upon so strictly different plans of 

uniform gradation from their lowest to 
personified in one highest plant, as the highest 



Again, Zoology is more a 



dvanced respecting the limitation of the most compre- 



hensive general divisions, than Botany, while Botany is in advance respecting the 






limitation and characteristics of families and genera 



There is, on that account, more 



diversity of opinion among 



of the primary divisions of the veg 

the great branches of the animal kingdom. 



botanists respecting the number, and the relative rank 

etable kingdom, than among zoologists respecting 



among 



plants, such primary groups 



* 

dones, under these or 
the Dicotyledones. 2 



While most writers 1 agree m admitting 

as Acotyledones, Monocotyledones, and Dicotyle- 

other names, others would separate the Gymnosperms from 



It appears to me, that this point 



the classification of the living plants cannot 



1 Goppert, etc., q. a., p. 93 



2 Ad. Brongniart, etc., q. a., p. 93 









' 












I . ■ 












I 
























• 












































































112 



ESSAY ON CLASSIFICATION. 



Part I 



be fully understood without a thorough acquaintance with the fossils and their 
distribution in the successive geological formations, and that this case exhibits 



influence classification may have upon 



the course of tim 



one of the most striking examples of the 

our appreciation of the gradation of organized beings in 

long as Gymnosperms stand among Dicotyledones, no relation 

the relative standing of living plants and the order of succession of their 
sentatives in past ages. 



As 



be traced between 

repre- 
On the contrary, let the true affinity of Gymnosperms 



with Ferns, Equisetaceas, and especially with Lycopodia 



b 



fully appreciated, and 



at once we see how the vegetable kingdom has been successively introduced upon 
earth, in an order which coincides with the relative position its primary divisions 
bear to one another, in respect to their rank, as determined by the complication 

of their structure. Truly, the Gymnosperms, with their imperfect flower, their open 
carpels, supporting their polyembryonic seeds in their axis, are more nearly allied 
to the anathic Acrophytes, with their innumerable spores, than to either the Mono- 
cotyledones or Dicotyledones ; and, if the vegetable kingdom constitutes a graduated 
series beginning with Cryptoganes, followed by Gymnosperms, and ending with 
Monocotyledones and Dicotyledones, have we not in that series the most striking 
coincidence with the order of succession of Cryptogams in the oldest geological forma- 
tions, especially with the Ferns, Equisetaceae, and Lycopodiacea3 of the Carboniferous 
period, followed by the Gymnosperms of the Trias and Jura and the Monocoty- 



ledones of the same formation and the late development of Dicotyledones? 



Here, 



as 



ywhere, there is but one order, one plan in nature 



■ 



SECTION XXV 



PARALLELISM BETWEEN THE GEOLOGICAL SUCCESSION OE ANIMALS AND THE EMBEYONIC 

GROWTH OE THEIR LIVING REPRESENTATIVES. 



Several authors have already alluded to the resemblance which exists between 



of the 



the young of some of the animals now living, and the fossil repr 

same families in earlier periods. 1 But these comparisons have, thus far, been traced 

only in isolated cases, and have not yet led to 

of the 



a conviction, that the character 



succession of organized beings in past ages, is such, in general, as to show 












1 Agassiz , (L.,) Poiss. foss., q. a., p. 54. 



Em- 



bryonic Types, q. a., p. 11. — Twelve Lect., etc., p. 8. 
Edwards, (H. Milne,) Considerations sur quel- 



ques principes relatifs h la Classification naturelle 
des animaux, An. Sc. Nat., 3e ser., 1844, 1 vol. 

p. 65. 














Chap. I 



SUCCESSION AND DEVELOPMENT OF ANIMALS 



113 



Milne-Edwards et Haime, q. a., p. 31 



Muller, (J.,) Seven papers, q. a., p. 71 



15 



II 









I 












j 



a remarkable agreement 

of our knowledge in Embryology 



with the embry 



growth of animals; though the state 



The facts most important 



and Palaeontology justifies now such a conclusion, 
proper appreciation of this point, have already been 
considered in the preceding paragraph, as far as they relate to the order of suc- 
cession of animals, when compared with the relative rank of their livin 
sentatives. In examining now the agreement between this succession and the ph 



g repr 



/ 



of the embry 



growth of 



living animals 



we may, therefore, take for granted 



that the order of succession of their fossil representatives is sufficiently present 
to the mind of the reader, to afford a satisfactory basis of comparison. 



Too 



few Corals have been studied embryologically, to afford extensive means of com 



parison ; yet so much is 



known, that the young polyp, when hatched, is an hide 



pendent, simple animal, that it is afterwards incased in a cup, secreted by the foot of 
the actinoid embryo, which may be compared to the external wall of the Rugom} 
and that the polyp gradually widens until it has reached its maximum diameter, 

stage of enlargement seems 



prior to budding 



dividing, while in ancient corals this 



last during their whole life, as, for example, in the Cyathophylloids. None of the 
ient Corals form those large communities, composed of myriads of united individ- 

stic of our coral reefs; the more isolated and more independent 



uals, so characteristic 

character of the individual polyps of past 



« 



presents a striking resemblance to 



the isolation of young corals, in all the living typ 
so much to learn still, as in Polypi, before the < 
growth, and their succession in time 
I would also remark, that among 



In no class is there, howeve 
spondence of their embryoni 



any one, even 



the highest type, represents in 



can be fully appreciated. In this connection 
the lower animals, it is rarely observed, that 

its metamorphoses all the stages of 



the lower types, neither in their development, nor in the order of their succession ; 

of the embryology of several types of differ- 
the connection of the whole series in both 



* 

and that frequently the knowled 
ent standing, is required, to ascertain 

* 

sph 



No class affords, as yet, a more complet 



and more beautiful evidence of the 



pondence of their embry 



changes, with the successive appearance of their 



presentatives in past 



g 



than the Echinoderms, thanks to the extensive and 



patient investig 



of J. Muller upon the metamorphoses of these animals 



Prior 



to the publication of his papers, the metamorphosis of the European Comatula alone 
was known. (See Sect. XYIIL, p. 85.) This had already shown, that the early stages 
of growth of this Echinoderm exemplify the peduncated Crinoids of past ages. I have 



myself seen further, that the 



ges of the embry 



growth of Comatula 



typify, as it were, the principal forms of Crinoids which characterize the successive 



\ 













































\\ 
























. ;. 











I 









' ■ 



































114 



ESSAY ON CLASSIFICATION 



Part I. 



geological format 



first, it recalls the Cistoicls of the palgeo 



rocks, which are 



represented in its simple spheroidal head, next the few-plated Platycrinoids of the 
Carboniferous period, next the Pentacrinoids of the Lias and Oolithe, with their whorls 
of cirrhi, and finally, when freed from its stem, it stands as the highest Crinoid, 
as the prominent type of the family, in the present period. 



The 



g 



of 



Mulle 



r 



up 



the larvae of all the families of living Asterioids and Echinoids enable 



us to extend these comparisons to the higher Echinoderms also. The first point 



which strikes the ob 



in the facts ascertained by Muller, is the 



rdinary 



similarity of so many larvae, of such different orders and different families as the 

Ophiuroids and Asterioids, the Echinoids proper and the Spatangoids, and even the 
Holothurioids, all of which end, of course, in reproducing their typical peculiarities. 
It is next very remarkable, that the more advanced larval state of Echinoids and 
Spatangoids should continue to show such great similarity, that a young Amphidetus 

extend these remarks too far, 
^us, as well as Echinus proper) 



hardly differs from a young Echinus. 1 Finally, not tc 
I would only add, that these young Echinoids (Spatan 



have rather a general resemblance to Cidaris, on account of their larg 
than to Echinus proper. 



spines 



Now, these facts 



agree exactly with what is known 



of the successive appearance of Echinoids in past ages; 2 their earliest representa 



tives belong to the g 



Diadema and Cidaris, next come true Echinoids, later 










only Spatangoids. When the embryology of the Clypeastroids is known, it will, 
no doubt, afford other links to connect a larger number of the members of this 

series. 

What is known of the embryology of Acephala, Gasteropoda, and Cephalopoda, 

affords but a few data for such comparisons. It is, nevertheless, worthy of remark, 
that while the young Lamettibranchiata are still in their embryonic stage of growth, 
thev resemble, externally at least, Brachiopods 3 more than their own parents, and 

>nic stage of growth, 



the young shells of all Gasteropods 4 known in their embry 
being all holostomate, recall the oldest types of that class. 



Unfortunately 



yet known of the embryology of the Chambered Cephalopoda, which are the 




ones found in the older geolog 



formations, and the changes which the shield of 



the Dibranchiata underg 



have 



yet been observed 



that no comparisons can 



be 
ord 



established between them and the Belemnites and other representatives of this 



in the middle and more 



recent geological 



■g 



Re 



ipecting Worms, our knowledge of the fossils is too fragmentary to lead to 
any conclusion, even should our information of the embryology of these animals 






1 Compare J. Miiller's 1st paper, pi. III., with 
pis. I V- VII., and with pis. VI. and VII., 4th paper. 



8 See the works, q. a., p. 73, note 1. 

4 See the works, q. a., p. 73, note 2, especially 



2 Agassiz, (L.,) Twelve Lectures, q. a., etc. p. 25. those relating to Nudibranchiata. 






»^» 






Chap. I. 



SUCCESSION AND DEVELOPMENT OF ANIMALS. 



115 



be sufficient as a basis for similar comparisons. The class of Crustacea, on the 
contrary, is very instructive in this respect ; but, to trace our comparisons through 
the whole series, it is necessary that we should consider simultaneously the em- 
bryonic growth of the higher Entomostraca, such as Limulus, and that of the highest 
order of the class, 1 when it will appear, that as the former recall in early life 
the form and character of the Trilobites, so does the 



young 



Crab 



passing through 






the form of the Isopods, and that of the Macrouran Decapods, before it assumes its 
typical form as Brachyouran, recall the well-known succession of Crustacea through 



the geological middle ages 
appearance of Scorpions, in 



and the tertiary periods to the present day. The early 

■ 

the Carboniferous period, is probably also a fact to the 

point, if, as I have "attempted to show, Arachnidians may be considered as exemplify- 

of Insects ; 2 but, for reasons already stated 

(Sect. XXIV.) it is hardly possible to take Insects into consideration in these inquiries 



ing 



the chrysalis stage of development 



In my researches upon fossil 



Fishes 3 I have pointed out at length the 



embryonic 



character of the oldest fishes, but much remains to be done in that direction. 
The only fact of importance I have learned of late, is that the young Lepidosteus, 
long after it has been hatched, exhibits in 



far only known among 



the form of its tail, characters, thus 

> 

the fossil fishes of the Devonian system. 4 It is to be hoped, 



throw some light 



upon 



the 



succession 



that the embryology of the Crocodile will 
of the gigantic Eeptiles of the middle geological ages, as I shall " show, that the 

the fossil Chelonians. It is already plain, 



embryology of Turtles throws light upon 



that the embryonic changes of Batrachians coincide with what is known of their 
succession in past ages. 5 The fossil Birds are too little known, and the fossil 

a sufficiently long series of geological formations 
striking points of comparison; yet, the characteristic peculiarities 

exhibit everywhere indications, that their living representa- 

-i ji_ •„ i.~ \ _ • i v 



Mammalia 6 do not extend through 



to afford 



many 



of their extinct genera 

tives in early life resemble them more 



than they do their own parents. A minute 



elephant, with any mastodon, will show this most fully, 
not mily in the peculiarities of their teeth, but even in the proportion of their 



comparison of a 



youno* 






limbs, their toes, etc. 



I 



It may, therefore, be considered as a 



general fact, v ery likely to be more fully 



illustrated as investigations cover a 



wider ground, that the phases of development 



V 



of all 



living animals correspond to the order of succession of their extinct repre- 



sentatives in past geological times. 




As far as this goes, the oldest representatives 



1 Agassiz, (L.,) Twelve Lectures, etc., p. 66 

2 Classif. of Insects, q. a., p. 85. 
8 Poiss. fossiles, q. a., p. 54. 

4 Agassiz, (L.,) Lake Superior, etc., p. 254. 



6 See the works, q. a., p. 82, note 3. 

6 Cuv., Oss. foss., q. a.: also, Agassiz, (L.,) 
Zoological Character of Young Mammalia, Proc. Am. 
Ass. Adv. Sc, Cambridge, 1849, p. 85. 













: 





































• i 


































- i 

w 1 




















































































•^ 



116 



ESSAY ON CLASSIFICATION. 



Part I. 



of 



y class may then be considered as embry 



*yp 



of their respective orders 



or families 



among the living. 



Pedunculated Crinoids are embry 



typ 



of the 



Comatuloids, the oldest Echinoids 



mbry 



presentatives of the higher living 



families, Trilobites embry 



typ 



of Entomostraca, the Oolitic Decapods embry 



types of our Crabs, the Heterocercal Ganoids embryonic types of the Lepidosteus, 
the Andrias Scheuchzeri an embryonic prototype of our Batrachians, the Zeuglodonts 
embryonic Sirenidae, the Mastodonts embryonic Elephants, etc. 

* 

To appreciate, however, fully and correctly all these relations, it is further neces- 
sary to make a distinction between embryonic types in general, which represent 
in their whole organization early stages of growth of higher representatives of the 
same type, and embryonic features prevailing more or less extensively in the charac- 

* 

ters of allied genera, as in the case of the Mastodon and Elephant, and what I 
would call hypembryonic types, in which embryonic features are developed to extremes 
in the further periods of growth, as, for instance, the wings of the Bats, which 
exhibit the embryonic character of a webbed hand, as all Mammalia have it at 
first, but here grown 
other families the shap 



out and developed into an organ of 



of 



a 



fin 



as in the Whale, or the Sea-turtle 



flight, or assuming in 

in which the 



close connection of the fingers is carried out to another extreme 



Without entering into further details upon this 



ubject, which will be fully 



illustrated in this work, enough has already been said to show, that the leading 



thought which runs throug 



the succession of 



all organized b 



gs in past ag 



is 



manifested 



«■ 



in new combinations, in the phases of the development of the 






living 



presentatives of these different typ 



It exhibits 



ywhere the working 



of the same creative Mind, through all times, and upon the whole surface of the 

■ 

globe. 









* 



1 



SECTION XXVI. 















PROPHETIC TYPES AMONG ANIMALS. 



i 

We have seen in the preceding paragraph, how the embryonic conditions of 

higher representatives of certain types, called into existence at a later time, are 
typified, as it were, in representatives of the same types, which have existed at 



an 



■ 

arlier period. These relations, now they 



satisfactorily known, may also be 



considered as 



plify 



■& 



as 



it were, in the diversity of animals of an earlier 



period, the pattern upon which the ph 



of the development of other animals 



i 
































Chap. I. 



PROPHETIC TYPES AMONG ANIMALS. 



117 



■ 

of a later period were to be established. They appear now, like a prophecy in 

those earlier times, of 
tions then prevailing in 



an order of things not possible with 



the earlier combina 



the animal kingdom, but exhibiting in a later period 



striking manner. 

animals. 



the antecedent considerations of every step in the gradation of 



This is, however, by no 



means the only, nor even the most remarkable case 



Recent investigations in Paleontology 



between animals of past ages 



m 



m 




of such prophetic connections between facts of different dates. 

have led to the discovery of relations 

and those now living, which were not even suspected 

by the founders of that science. It has, for instance, been noticed, that certain types 

which are frequently prominent among the representatives of past ages, combine 

their structure, peculiarities which at later periods are only observed separately 

different, distinct types. Sauriod Fishes before Reptiles, Pterodactyles before Birds, 

* 
* 

osauri before Dolphins, etc. 
ThereTare entire families, among the representatives of older periods, of nearly 
every class of animals, which, in the state of their perfect development exemplify 
such prophetic relations, and afford, within the limits of the animal kingdom, at 
least, the most unexpected evidence, that the plan of the whole creation had been 
maturely considered long before it was 
time past, been in 

past geological ages y 

ceded the appearance 







executed. Such types, I have for some 
the habit of calling prophetic types. The Sauroid 1 Fishes of the 



are an 



example of this kind. These Fishes, which have pre- 
of Reptiles, present a combination of ichthyic and reptilian 



characters, not to be found in 
at present. 



the true members of this class, which form its bulk 



The Pterodactyles 2 which have preceded the cjass of Birds, and the 
Ichthyosauri 3 which have preceded the appearance of the Crsitacea, are other exam- 




■ 

pies of such prophetic types. 



These cases suffice for the present, to show that 



there is a 



real difference between embryonic types and prophetic types. Embryonic 



types are in a measure 
liarities of development 



also prophetic types, but they exemplify only the pecu- 
of the higher representatives of their own types; while 



prophetic types exemplify structural combinations observed at a later period, in two 
or several distinct types, and are, moreover, not necessarily embryonic in their 
character, as for example, the Monkeys in comparison to Man; while they may be 

of the Pinnate, Plantigrade, and Digitigrade Carnivora, or still 



so, as in 



the 



case 



more so in the case of the pedunculated Cnnoids. 

Another combination is also frequently observed among animals, when a series 

- 

exemplifies a natural gradation, without immediate 



exhibits such a succession as 



1 Agassiz, (L.,) Poiss. foss., vol. 2, part 2 

2 Cttvier, (G.,) Oss. foss., vol. 5,. p. 2. 



8 Cuvier, (G.,) Oss. foss., as q. a. 

4 See above, Sect. 25. 


































' 















■ 























































Ilj 














































118 



ESSAY ON CLASSIFICATION. 



Part I. 



or necessary reference to either embryonic development or succession in time, as the 
Chambered Cephalopods. Such types I call progressive types} 

Again, a distinction ought to be made between prophetic types proper and 
what I would call synthetic types, though both are more or less blended in nature. 
Prophetic types proper, are those which in their structural complications lean towards 

- 

other combinations fully realized in a later period, while synthetic types, are those 



which combine, in a 



well balanced measure, features of 



several types occurring as 



distinct, only 



later time. Sauroid Fishes and Ichthy 



are more distinctly 



ynthetic than prophet 



*JP 



while Pterodactyles have more the character of 



prophet 



*yp 



so are also Echinocrinus with refer 



to Echini, Pentremites wi 



reference to Asterioids, and Pentacrinus with reference to Comatula. Full illustra- 
tions of these different cases will yet be needed to render obvious the importance 

■ 

of such comparisons, and I shall not fail, in the course of this work, to present 
ample details upon this subject. Enough, however, has already been said to show, 
that the character of these relations among animals of past ages, compared with those 
of later periods or of the present day, exhibits more strikingly than any other 
feature of the animal kingdom, the thoughtful connection which unites all living 
b eings, through all 



ages, into one great system, intimately linked together from 



beginning to end. 



SECTION XXVII 



PAEALLELISM BETWEEN THE STRUCTTJKAL GRADATION OF ANIMALS AND THEIR 

EMBRYONIC GROWTH. 






So striking is the resemblance of the young of higher animals to the full-grown 



* 

individuals of lower types, that it has been assumed by many writers that all the 



higher animals pass 



during the earlier stages of their 



growth, through phases cor- 



responding to the permanent constitution of the lower classes. These suppositions, 

■ 

the results of incomplete investigations, have even become the foundation of a 
system of philosophy of Nature, which represents all animals as the different degrees 
of development of a few primitive types. 2 These views have been too generally 

* 

circulated of late, in an anonymous work, entitled "Vestiges of Creation/' to require 



1 Agassiz, (L.,) On the Difference between don. Telliamed,) Entretiens <Tun Philosophe indien 
Progressive, Embryonic, and Prophetic Types, etc., avec un missionaire frangais, Amsterdam, 1748, 2 



Proc. Am. Ass. Adv. Sc, Cambridge, 1849, p. 432. 



vols. 8vo. — Oken, (Lor.,) Lehrbuch der Natur-Phi- 



2 Lamarck, q. a., p. 26. — DuMaillet, (Pseu- losophie, q. a., p. 18. — The Vestiges of Creation, etc. 













mmsm 



mamammm 



■ 




H 












Chap. I. 



RANK AND DEVELOPMENT OF ANIMALS. 



119 



further mention here. 



It has also been shown above (Sect. VIII.) that animals do 



not form snch a simple series 



as 



would result from a successive development. 



There remains, therefore, only for us 



to show now within what limits the natural 



gradation which may be traced in 



the different types of the animal kingdom, 1 cor- 



responds to the changes they undergo during their growth, having already considered 
the relations which exist between these metamorphoses and the successive appear- 

ance of animals upon 

relative standing of their living representatives 

of structure of all animals is s 
random, our 



earth and between the latter and the structural gradation or 

Our knowledge of the complication 

ufficiently advanced to enable us to select, almost at 



examples of the correspondence between the structural gradation of 
animals' and their embryonic growth, in all those classes the embryologic develop- 
ment of which has been sufficiently investigated. 



Yet, in order to show more 



distinctly how closely all the leading features of the animal kingdom are combined, 
whether we consider the complication of their structure, or their succession m time, 
or their embryonic development, I shall refer by preference to the same types 



which I 



have chosen before for the illustration of the other relations. 



Among Echinoderms, we find in 



the order of Crinoids the pedunculated types 



standing lowest, 2 Comatulse highest, and it is 



well known that the 



young 



Comatula 



is a 



pedunculated Crinoid, which only becomes free in later life. 



3 



J. Miiller has\ 



shown that 



among the Echinoids, 



even 



goids, differ but slightly in early youth 



the highest representatives, the Spatan- 
from the Echinoids, and no zoblog 



ist x 

t 



\ 



can doubt that these are 
insisted particularly upon 



inferior to the former. 



Among Crustacea, Dana 4 has 



the serial gradation which may be traced between the 
different Vpes of Decapods, their order being naturally from the highest Bruchyoura, 
through the Anomonra, the Macroura, the Tetradecapods, etc., to the Entomostraca ; 
the Macrouran character of the embryo of our Crabs has been fully illustrated 



- 



his beautiful investigations upon the embryology of Crustacea. 



by Kathke, 5 in 

have further shown that the young 

forms, some of these young 

order. 6 



I 



of Macroura represents even 



Entomostraca 



having been described as representatives of that 
The correspondence between the gradation of Insects and their embryonic 



growth, I have illustrated fully in a special paper 



made in the class of Fishes; 8 among 



Reptiles, we 



Similar comparisons have been 
find the most striking examples 



1 See the works quoted from p. 67-87, also Milne- 
Edwards, q. a., p. 112. — Thompson, Crinoids, q. a. 

2 Muller, (J.,) Ueber Pentacrinus Caput-Me- 
dusse, Berlin, 1833, 4to., Ak. d. Wiss. 

3 Forbes, (Ed.,) History of British Starfishes, 

London, 1851, 1 vol. 8vo., p. 10. 



4 Dana, q- a, 



p. 32. 



Rurmeister, Cirripeds, 



q. a., p. 79. — Thompson, q. a., p. 79 
6 Eathke, q. a., p. 79. 

6 Twelve Lectures, etc., p. 67. 

7 Classification of Insects, q. a. 

8 Poissons fossiles, q. a. 












I 














































, 









120 



ESSAY ON CLASSIFICATION. 



Part I. 






































young, exhibits another correspondence between the young 






of this kind among Batrachians 1 (see, above, Sect. XII); among Birds, 2 the uniformly 
webbed foot, in all 

of higher orders and the permanent character of the lower ones. In the order 
of Carnivora, the Seals, the Plantigrades, and the Digitigrades exemplify the same 
coincidence between higher and higher representatives of the same types, and the 
embryonic changes through which the highest pass successively. 

No more complete evidence can be needed to show that there exists throughout 
the animal kingdom the closest correspondence between the gradation of their types 
and the embryonic changes their respective representatives exhibit throughout. And 
yet what genetic relation can there exist between the Pentacrinus of the "West 
Indies and the Comatulee, found in every sea; what between the embryos of Spatan- 
goids and those of Echinoids, and between the former and the adult Echinus; 
what between the larva of a Crab and our Lobsters; what between the Caterpillar 
of a Papilio and an adult Tinea, or an adult Sphinx; what between the Tadpole 
of a Toad and our Menobranchus ; what between a young Dog and our Seals, 
unless it be the plan designed by an intelligent Creator? 












SECTION XXVIII 



THE STRUCTURE, EMBRYONIC GROWTH, GEOLOGI 
THE GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 



SUCCESSION, AND 






It requires unusual comprehensiveness of view to perceive the order prevailing 

- 

in the geographical distribution of animals. We should, therefore, not wonder that 

r 

this branch of Zoology is so far behind the other divisions of that science. Nor 
should we wonder at the fact that the geographical distribution of plants is so much 

■ 

better known than that of animals, when we consider how marked a feature the 

a 

vegetable carpet which covers the surface of our globe is, when compared with the 
little show animals make, almost everywhere. And yet it will, perhaps, some day, 
be easier to understand the relations existing between the geographical distribution 

- 

L * 

of animals and the other general relations prevailing among animals, because the 



ge of structural differences is much g 



among animals than among 




Even now, some curious coincidences may be pointed out which go far to show 
that the geographical distribution of animals stands in direct relation to their rela- 



1 Twelve Lectures, etc., p. 8. 



2 Agassiz, (L.,) Lake Superior, etc., p. 194. 






* 
















Chap. I. GRADATION, GROWTH, SUCCESSION, DISTRIBUTION. 



121 



tive standing in their respective 
past geological ages, 






classes, and to the order of their succession in 

and more indirectly, also, to their embryonic growth. 

Almost every class has its tropical families, and these stand generally highest 

in their respective classes; or, when the contrary is the case, when they stand 

evidently upon a lower level, there is some prominent relation between them and 



the prevailing types of past ages. 
of these two kinds of connection. 



The class of Mammalia affords striking examples 
In the first place, the Quadrumana, which, next 



to Man, stand highest in 



their class, are all tropical animals; and it is worthy of 



f/ 



L 



remark, that the two highest types of Anthropoid Monkeys, the Orangs of Asia and 
the Chimpanzees of Western Africa bear, in the coloration of their skin, an addi- 
tional similarity to the races of Man inhabiting the same regions, the Orangs being 
yellowish red, as the Malays, and the Chimpanzee blackish, as the Negroes. The 
Pachyderms, on the contrary, stand low in their class, though chiefly tropical ; but 
they constitute a group of animals prominent among the earliest representatives of 
that class in past ages. Among Chiroptera, the larger frugivorous representatives are 
essentially tropical ; the more omnivorous, on the contrary, occur everywhere. Among 
Carnivora, the largest, most powerful, and also highest types, the Digitigrade, prevail 
in the tropics, while among the Plantigrades, 



to the temperate and to the arctic zone, 
species of the temperate and arctic seas. 



and the Camels in the warmer zones, the others everywhere. 



the most powerful, the Bears, belong 

and the lowest, the Pinnate, are marine 

Among Ruminants, we find the Giraffe 

In the class of Birds 



the gradation is not so obvious as in 



other classes, and yet the aquatic types form 



are 
the 



by far the largest representation of this class in temperate and cold regions, and 

almost the only ones found in the arctic, while the higher land birds prevail in 

Among Reptiles, the Crocodilians are entirely tropical ; the largest 
land Turtles are also only found in the tropics, and the aquatic representatives of 
this order, which are evidently inferior to their land kindred, extend much further 
north. The Rattlesnakes and Vipers extend further north and higher up the moun- 



. warm regions 



tains than the Boas and the common 



harmless snakes. 



The same is true of Sala- 



manders and Tritons. The Sharks and Skates are most diversified in the tropics. It 
is also within the tropics that the most brilliant diurnal Lepidoptera are found, and 



Among Crustacea the highest order, the Bra- 



this is the highest order of Insects. 

chyoura, are most numerous in the torrid zone; but Dana has shown, what was not 

at all expected, that they nevertheless 

1 The Anomoura and Macroura, on the contrary, are nearly 



reach their highest perfection in the middle 



temperate regions. 1 

equally divided between the torrid and temperate zones; while the lower Tetrade- 

capods are far more numerous in extra tropical latitudes than in the tropical. The 



1 Dana, Crustacea, p. 1501 

16 







■ 



i 


















W~ 












































i ■ 
















































■ : 














I 















122 



ESSAY ON CLASSIFICATION 



Part I. 




























































Cephalopods are most diversified within the tropics; yet the Nautilus is a reminis- 
cence of past ages. Among Gasteropods, the Stromboids belong to the tropics; but 
among the lamellibranchiate Acephala, the Naiades, which seem to me to stand very 
high in their class, have their greatest development in the fresh waters of North 
America. The highest Echinoderms, the Holothurians and Spatangoids are most diver- 
sified within the tropics, while Echini, Starfishes, and Ophiurse extend to the arctics. 
The 



presence of Pentacrinus 



r 

the West Indies has undoubtedly reference to the 



prevalence of Crinoids 

^ 

noid Polypi, 



past 



g 



The Madrep 



■ 

the highest among the Acti 



are 



ely tropical, while the highest Halcyonoids, the Renilla, Vere 



tillum, and Pennatula, extend to the tropics and the temperate zone. 



Another interesting relation b 



the geographical distribution of animals and 



their 



regions. 



presentat 



. 



in 



past 



ges, is 



the absence of embry 



tyP 



the 



warm 



* 

We find in the torrid zone no true representatives of the oldest g 



logical periods ; Pentacrinus is not found before the Lias ; among Cephalopods we 
find the Nautilus, but nothing like Orthoceras; Limulus, but nothing like Trilobites. 

i 

This study of the relations between the geographical distribution of animals, and 



their relative standing 



dered more difficult, and in many respects obscure, by 



the circumstance that entire types, characterized by peculiar structures, are so 
strangely limited in their range ; and yet, even this shows how closely the geographi- 
cal distribution of animals is connected with their structure. Why New Holland 



Pachyderms, no Edentata, 

st knows, and is 



g 



should have no Monkeys, no Carnivora, no Kuminants, no 

is not to be explained; but that this is the case, every 

further aware, that the Marsupials 1 of that continental island represent, as it were, 

- 

the other orders of Mammalia, under their special structural modifications. New 
Holland appears thus as a continent with the characters of an older geological age. 
No one can fail, therefore, to perceive of how great an interest for Classification 
will be a more extensive knowledge of the geographical distribution of animals in 
general, and of the structural peculiarities exhibited by localized types. 






SECTION XXIX. 



MUTUAL DEPENDENCE OE THE ANIMAL AND VEGETABLE KINGDOMS 



Though it had long been know 
breathing process of animals and 



by the 




are 



xperiments of De Saussure, that the 
ery different, and that while the for- 






1 See Sect. 11. 











Hi. ~ 










{ 



Chap. I. 



PARASITIC ANIMALS. 



123 



mer inhale atmospheric air, and exhale carbonic acid gas, the latter appropriate 
carbon and exhale oxygen, it was not until Dumas and Bousingault 1 called partic- 

* 

ularly the attention of naturalists to the subject, that it was fully understood how 
direct the dependence is of the animal and vegetable kingdoms one upon the other, 
in that respect, or rather how the one consumes what the other produces, and vice 



versa 



thus tending to keep the balance which either of them would singly disturb 



to a certain degree. 



The common agricultural 



practice of manuring exhibits from 



another side the dependence of one kingdom upon the other: the undigested 
particles of the food of animals return to the ground, to fertilize it for fresh pro- 
duction. 2 Again, the whole animal kingdom is either directly or indirectly dependent 
upon the vegetable kingdom for its sustenance, as the herbivorous animals afford 



that Worms originated in 



We are too far from the time when 

* 

the decay of fruits and other vege- 



the needful food for the carnivorous tribes. 

itBcouldlbe supposed 

table substances, to need here repetition of what is known respecting the repro- 
duction of these animals. Nor can it be necessary to show how preposterous the 
assumption would be that physical agents produced plants first, in order that from 
these, animals might spring forth. Who could have taught the physical agents to 
make the whole animal world dependent upon 



the vegetable kingdom? 



On the contrary, such general facts as those above alluded to, show, more directly 
than any amount of special disconnected facts could do, the establishment of a well- 
regulated order of things, considered in advance ; for they exhibit well-balanced 
conditions of existence, prepared long beforehand, such as only an intelligent being 

- 

could ordain. 



S 


























SECTION XXX. 



PARASITIC ANIMALS AND PLANTS. 



However independent of each other some animals may appear, there are yet 



many which live 
which are known 



mly 
nly 



m 



as 



the closest connection with their fellow 
parasites upon or within them 



and 



Worms, and all the vermin of the skin 



3 



Such are the intestinal 
Among plants, the Mistletoe, Orobanche, 



Dumas, Lecjon sur la statique chimique des 



1 and 2 ; see also Rudolphi, (K. A.,) Entozoorum 



etres organist, Ann. Sc. Nat. 2de ser. vol. 6, p. 33; sive Vermium, etc., q. a., p. 31.-B R emser, (J. G.,) 
rft i i7 „ ioo Ueber lebende Wurmer im lebenden Menschen. 



vol. 17, p. 122. 



istry, 



Liebig, Agricultural Chemistry ; Animal Chem- 



W 



8 See above, p. 76, notes 1 and 2, and p. 77, notes 



Helminthes, etc., q. a., p. 32. 
Historia Vermium, etc., q. a., p. 32. 



Dujardin, (F.,) Hist. Nat. des 



M.,) 



I 









































































































>l 












124 



ESSAY ON CLASSIFICATION. 



Part I. 



Rafflesia, and many Orchideae may be quoted as equally remarkable examples of 
parasitism. 



There exists the greatest variety of parasites among animals 



It would take 



volumes to describe them and to write their history, for their relations to the 
animals and plants upon which they are dependent for their existence are quite 
as diversified as their form and their structure. 

It is important, however, to remark, at the outset, that these parasites do not 



constitute for themselves one g 



division of the animal kingdom. They belong, 



t 

on the contrary, to all its branches; almost every class has its parasites, and in 



none do they represent 



natural order. This fact is very significant 



shows 



beings equally close. 



at once that parasitism is not based upon peculiar combinations of the leading 

■ 

structural features of the animal kingdom, but upon correlations of a more specific 
character. Nor is the degree of dependence of parasites upon other organized 

There are those which only dwell upon other animals, while 

* 

others are so closely connected with them that they cannot subsist for any length 
of time out of the most intimate relation to the species in which they grow and 
multiply. Nor do these parasites live upon one class of animals; on the contrary, 

■ 

they are found in all of them. 

— » _ _ — — — _ 

me among 
Mammalia. Among Birds, a few species depend upon others to sit upon their 

Cuckoo, and the North American Cowbird. 

vity of the 



Among Vertebrata there are few parasites, properly speaking. N 



eggs and hatch them, as the European 

Among Fishes, some small Ophidiums (Fierasfers) penetrate 



the 



body of large Holothuriae in which they dwell 



1 



Echeneis attach themselves 



other fishes, but only temporarily. Among Articulata, the number of parasites 



largest 



It seems to lie in the very character of this type, so remarkable for the 



outward display of their whole organization, to include the g 



parasites 



And it is 



lly among them, that 



we observe the most 



variety of 
traordinary 



combinations of this 



g 



mode of existence. 



Insects 



general, are more particularly dependent upon 




for their sus- 



tenance than herbivorous animals 



lly are, inasmuch as most of them are 



limited to particular plants for their whole life, such as the Plant 



the Coccus 



the Gall Insects. In others, the larvae only 



limited to particular plants, while 



the larvae of others still, such as the Bots, grow and undergo their development 
under the skin or in the intestines, or in the nasal cavities of other animals. 



The 



Ichneumons lay their eggs in the larvae of other insects, upon which the young 
larvae prey until hatched. Among perfect Insects, there are those which live only 
in community with others, such as the Ant-Hill Insects, the Clavigers, the Clerus, 



• 



1 See above, p. 74, note. 



- 











\ 



Chap. I. 



PARASITIC ANIMALS. 



125 



Different kinds of Ants live together, if not as parasites one npon another 



and Bees. 

at least in a land of servitude 



Other Insects live npon the bodies of warm 



blooded animals, such as 



the Fleas and Lice, and of these the number is leg 



Some Hydrachnas are parasiti 



upon 



quatic Mollusks 



i 



Among Crustacea, there are Crabs constantly living in the shell of Mollusks, 

the Pinnotheres of the Ovster and Mussel. I have found other species upon 



such as 

■ 

Sea-Urchins, (Pinnotheres Melittse 

Paguri take the shells of Mollusks to protect 



a 



new species, upon Melitta quinquefora). 

themselves: while a vast numb 



The 
r of 



upon Fishes 



2 



Amphipods live 

skin, or upon Starfishes 

are parasites upon the Whales, others upon 

the females are mostly parasites upon the 



ttached to their gills, upon their tongue, or upon their 



The Cyamus Ceti lives upon the Whale 




ills 



Some Cirripeds 
Corals. In the family of Lernaeans, 

- 

fins or upon the body of Fishes, 



while the males are 



free 



Among Worms this mode of existence is still more frequent, and while some 



but her 



«■ 



we 



only of genuine parasites 
find the most diversified relations; for, while some are con- 



dwell only among Corals, entire families of others 



tantly parasitic, others depend 




for a 



certain period of their life upon other 



animals for their existence. 

into the body of Insects, and leaves them 

lives free in the water as 

animals; the Taenia, on the contrary, is a 



The young Gordius is a free animal 



'& 



; it then creeps 

propagate; the young Distoma 

its life in other 



Cercaria, and spends the remainder of its 

parasite through life, and only 



pass 



from one 



animal into the other. But what is 



most 



aordinary 



egg* 
this 



as 



in many other 



testinal Worms 



transformations in some 



the fact, that while they undergo their first 
kind of animals, they do not reach their complete develop- 

iing swallowed up by 
the case with many Filariae, 



ment until they pass into the body of another^ higher type, b 
this while in the body of their first host 



Such 



the Taeniae and Bothrocephali. 
being swallowed by Sharks or 



These 



first 



Water Birds, or 



nhabit lower Fishes, and these Fishes 
Mice with their Worms being eaten 



up by C 



the parasites 



living m 



them undergo their final transformation 



the 



latter. Many Worms undertake extensive 
animals, before they reach the proper pla 



migrations 



through the bodies of other 



for their final development 



3 



1 Nitzsch, (Chr. L.,) Darstellung der Familien 
und Gattungen der Thierinsekten, Halle, 1818, 8vo. 

Hayden, (C. v.,) Versuch einer systematischen 
Eintheilung der Acariden, Isis, 1826, p. 608.— 
Ratzenburg, (J. S. C.,) Die Ichneumonen der 
Forstinsekten, Berlin, 1844-52, 3 vols. 4to. fig- 
Clark, (Br.,) Observations on the Genus Oestrus, 



Die Pflanzen-Lause, Aphiden, Niirnberg, 1846, 8vo. 

Recherches sur l'ordre des 



fig. — Duges, (Ant.,) 



Trans. Lin. Soc, III., p. 289, fig. 



Koch, (C. L.,) 



Acariens, Ann. Sc. Nat., 2de ser., 1834, 1., p. 5, II., 

p. 18, fig. 

2 I have found a new genus of this family upon 
Asterias Helianthoides. 

8 See above, p. 76, note 1 ; Siebold, Wanderung, 
etc., p. 77, note 1 ; Steenstrup, etc. 







































\ 













TT ^K *r 









• 
































































1 

1 












» 






1 
























• 














* 






\ 














1 

1 






































ft 





126 



ESSAY ON CLASSIFICATION. 



Part I 



Among Mollusks, parasites are very few, if any can properly be called true 






parasites, as the males of some Cephalopods living upon their own females 



the 



Gasteropods 



found 



gr < 
in Corals 



buried in Corals, 2 and the Lithodomus and 



ety of Areas 



Among Kadiata there are no parasites, properly speak 



some 



of them only attaching themselves by preference to certain plants, while the young 
of others remain connected with their parent, as in all Corals, and even among 






Crinoids, as in the Comatula of Charleston 



In all these different cases, the chances that physical 



<g 



may have a share 



in 



produ 



such animals are still less than in the cases of independent animals 



for here we have 



peradded to the very 



existence of these beings all the 



com 



plicated circumstances of their peculiar mode of existence and their various con- 



nections with other animals 



Now, if it can already be shown from the mere 



connections of independent animals 



external circumstances cannot be the cause 



of their existence, how much less could such 
It is true. 



an 



g 



b 



f 



ascribed! to parasites 

they have been supposed to originate in the body of the animals upon 

which they live. What then of those who enter the body of other animals at 

,ge of growth, as the Gordius ? Is it a freak of his ? 

; are they the 



a somewhat advanced st; 

Or, what of those which only live upon other animals, such as lice 



product of the skin? Or, what of those which have to pass from the body of 
a lower into that of a higher animal, to undergo their final metamorphosis and 

■ 

in which this succession is normal? Was such an arrangement devised by the first 
animal, or imposed upon the first by the second, or devised by physical i 



g 



for the two? Or, what of those in which the females 




are parasites 



Had 



the two sexes a different origin 



? 



Did perhaps the males and females 



g 



in different ways? 



I am at a loss to conceive how the origin of parasites can be ascribed to 



causes 



g 



physical causes, unless, indeed, animals themselves be considered as physical 
with reference to the parasites they nourish ; and if so, why can they not 
rid of them, as well as produce them, for it cannot be supposed, that all this 

consciously, when parasites bear such close structural relations to the 

various types to which they belong? 

The existence of parasitic animals belonging to so many different types of the 



is not done 



animal as well as the vegetable 

o 



kingdom 



is a fact of deep meaning, which Man 
stly consider, and, while he may marvel at the fact, take 
it as a warning for himself, with reference to his boasted and yet legitimate inde- 



himself cannot too 






1 See above, p. 74, note 1, Kolliker, Muller, 



*■ 



Verany and Vogt, etc. 



2 Ruppell, (Ed.,) Memoire sur le 
antiquus, Trans. Soc. Strasb., 1832, L, fig. 



Magilus 



• 



. 

















I 

Chap. I. 



COMBINATION OF RELATIONS. 



127 



pendence. 



All relations in nature are regulated by a superior wisdom. 



May 



we 



only learn in 



the end to conform, within the limits of our own 



phe 



to the 



laws assigned to each race 



t 






SECTION XXXI. 



COMBINATION IN 



TIME AND SPACE OF VARIOUS KINDS OE RELATIONS 



ANIMALS 



It must occur to every 



reflecting mind, that the mutual relation and respect 



parallelism of so many structural, embry 



geological, and geographical charac 



teristics of the animal kingdom are 



the most conclusive proof, that they were 



ordained by a 



nature most accessible to our 



reflective mind, while they present at the same time the side of 

seeking to penetrate the relations 



g 



when 



between finite beings and the cause of their existence. 



The phenomena of the inorganic 



world are all simple, when compared to those 



of the 



g 



world 



There is 



not one of the g 



physical ag 



electricity 



magnetism, heat, light, or 



chemical aflinity, which exhibits, in its sphere, as com 



plicated phenomena as the simplest 



g 



nized being 



and we need not look for 



the highest among 



the latter to find them presenting the same physical phenomena 



as are manifested in the material world, besides those which are exclusively pecu- 

i include every thing the material world 



liar to them 



When, then, organized being 



contains, and a g 



deal more that is peculiarly their own, how could they be 



produced by physical causes 



and how can the physicists, acquainted with the laws 



of the material world, and who acknowledg 



that these laws must have been 



established at the beg 
which regulate the org 



overlook that ci fortiori the more complicated laws 
world of the existence of which there is no trace for 



a long period upon 



the surface of the earth, must have been established, later 



and 



ssively 



at the time of the creation of the successive typ 



of animals 



and plants ? 
Thus far, w 



have been considering chiefly the contrasts existing between the 



organic and 



'g 



worlds. 1 At this 



<g 



of our 



g 



# 

it may not be 



out of 




to take a 




lance at some of the coincidences which may be traced 



between them, especially as they 



a 



fiord direct evidence that the physical world 



has been ordained in conformity with 
and disclose, in both spheres 



which obtain 



among living being 



equally plainly, the workings of a reflective mind 







i 















Compare Sects. 24, 25, 26, 27, 28, 29, and 30. 












































128 



ESSAY ON CLASSIFICATION 



Part I 









11 











































It is well known, that the 



gement of the leaves in 




1 



may be expressed 



by very simple series of fractions, all of which are gradual approximations to, or 



means between A or 



the natural 



mum and the minimum diverg 



|, which two fractions are themselves th 



9 maxi 



between two 



gle successive leaves 



The 



normal series of fractions which expresses the various combinations most frequently 



observed 



among the leaves of plants, is as follows: 



1 1 2. 3. _5_ _8_ 13. 11 
2? 3? 5? 8> 13? 21? 34? 55 



, etc 



Now, upon comparing this arrangement of the leaves in plants with the revolu- 
tions of the members of our solar system, Peirce has discovered the most perfect 
identity between the fundamental laws which regulate both, as may be at once 
seen by the following diagram, in which the first column gives the names of the 
planets, the second column indicates the actual time of revolution of the successive 



pressed 



m 



day 



planets, e: 
the planet 
should have a ratio to those upon each side of 



the third column the successive times of revolution of 



which are derived from the hypothesis that each time of revolution 

which shall be one of the 




ratios of the law of phyll 



and the fourth column, finally, g 



the normal 



series of fractions expressing the law of the phyllotaxis. 










Neptune, 

Uranus, 

Saturn, 

Jupiter, 

Asteroids, 

Mars, 

Earth, 

Venus, 
Mercury, 



60,129 
30,687 . 
10,759 
4,333 . 
1,200 to 2,000 
687 . 
365 . 

88 



62,000 

31,000 

10,333 

4,133 

1,550 

596 

366 

227 

, 87 



8 



13 
21 








£ 



s 



*> 



8 




13 












In this series the Earth forms a break; but this apparent 



gularity admits 



The fractions 



■ 

of an easy explanation. 

position of successive leaves upon an ax 

spiral, are identical, as far as their meanin 



b b b b iz> A? ib etc -> as expressing the 



by the short way of ascent along the 
3 concerned, with the fractions express- 



g 



these same positions, by the long way, namely 



12 3 5 __8_ 13. 12 pf n 
2? 3? 5? 8? 13? 2 1? 34> ctu# 



Let us, therefore, repeat our diagram in 



the theoretical time of revolution 



another form, the third column giving 




Neptune, 



u 



Uranus, 



« 






i 
i 



i 

2 

X 
2 






62,000 

62,000 

31,000 

• 15.500 



60,129 



30,687 






1 See the works quoted above, p. 18, note 3. 






■I I II II tf 






^ 






Chap. I. 



COMBINATION 



Saturn, 



u 



Jupiter, 



u 



Asteroids, 






a 



Mars, 

Earth, 
Venus, 



u 



[NATION 


OF 


RELATIONS. 




• > 


10,333 


• t • ' 


• • 


6,889 . 

■ 


t • 


• 


4,133 


• t ' ' 


• 

* 


2,480 . 


*-. • 


• 


1,550 . . 


• f ' ' 


• 


968 . 


J% • 


•> 
• 


596 . . 


• ■• . • A ■ • 


• 


366 . 

* 


H • 


• ■ 


227 ... . 


. W • • 


• 


140 . 



129 



Mercury, 



21 



87 



10,759 



4,333 



1,200 



687 
365 
225 



88 




It 



appears 



from this table, that two intervals usually elapse between two suc- 



cessive planets, so 



that the normal order of actual fractions is 



1 1 1 3. _5_ 

2; 3? 5? 8? 13? 



or the fractions by the short way in 



etc., 

» 

phyllotaxis, from which, however, the Earth 



end of a single 



is excluded, while it forms a member of the series by the long way. The explana- 
tion of this, suggested by Peirce, is that although the tendency to set off a planet 

is not sufficient at the 

end of the second interval, that the planet is 

second interval. Thus, Uranus is rather too far from the Sun relatively to Neptune, 

Saturn relatively to Uranus, and Jupiter relatively to Saturn, and the planets thus 

formed engross too large a proportionate share of material and this is especially 



interval, it becomes so strong near the 

i 

a 

found exterior to the limit of this 



the case with Jupiter. Hence, when we 



come to the Asteroids, the disposition is 
that the outer Asteroid is but just within 

this interval, and the whole material of the Asteroids is dispersed in separate masses 
over a wide space, instead of being cone 



so strong 



at the end of a single interval, 



entrated into a single planet. 



A 



conse- 



of this dispersion of the forming agents is, that a small proportionate 



quence 

material is absorbed into the Asteroids. 



Hence, Mars is ready for formation so 



far exterior to its true place, that when the next interval elapses the residual 



force 



> - 



becomes strong enough to 



form the Earth, after which the normal law is resumed 



without any further disturbance. 



Under this law, there can be no planet exterior 



to Neptune, but there may be one 



interior to Mercury. 



Let us now look back upon some 



of the leading features alluded to before, 



omitting the simpler relations of organized beings to the world around, or those of 
individuals to individuals, to consider only the different parallel series we have been 



- 

comparing when showing that, in 



their respective great types, the phenomena of 



animal life correspond to one 



another, whether we compare their rank as deter- 



mined by structural complication with the phases of their growth, or with their 

past geological ages; whether we compare this succession with their 



succession m 



embryonic growth, or all these different relations with each other and with the geo- 



17 
























■V (I 






■■ 
































■ 



• 
































































il ' 








: 












130 



ESSAY ON CLASSIFICATION. 



Part I. 



graphical distribution of animals upon earth. The same series everywhere ! * These 

of the animal kingdom, so far as we have 



facts 



are true of all the 



g 




pursued the 



g 



and though, for want of materials, the train of evidence 



is incomplete in some instances, yet we have proof 



gh for the establishment 



of this law of a 



ersal 



ipondence 



m 




the leading features which binds 



all organized beings, of all times 



into one great system, intellectually and intelligibly 

* 

linked together, even where some links of the chain are missing. It requires con- 
siderable familiarity with the subject even to keep in mind the evidence, for, 
though yet imperfectly understood, it is the most brilliant result of the combined 



intellectual efforts of hundreds of investigators during half a century 



The 



connec- 



tion, however, between the facts, it is easily seen, is only intellectual; and implies, 
therefore, the agency of Intellect us its first cause. 2 

And if the power of thinking connectedly is the privilege of cultivated minds 



nly 



if the power of combining different thoughts, and of drawing from them new 



thoughts, is a still rarer privilege of a few superior minds; if the ability to trace 

- 

simultaneously several trains of thought is such an extraordinary gift, that the few 
cases in which evidence of this kind has been presented have become a matter 

* 

* 

of historical record (Caesar dictating several letters at the same time), though they 
exhibit only the capacity of passing rapidly, in quick succession, from one topic to 
another, while keeping the connecting thread of several parallel thoughts: if all 



this is only possible for the 



highest intellectual 



powers, shall we by any false 



argumentation allow ourselves to deny the intervention of a Supreme Intellect in 

existence combinations in nature, by the side of which, all human 



calling 







conceptions are child's play? 

If I have succeeded, even very imperfectly, in showing that the various rela- 
tions observed between animals and the physical world, as well as between them- 
selves, exhibit thought, it follows, that the whole has an Intelligent Author, and it 
may not be out of place to attempt to point out, as far as possible, the difference 
there may be between Divine thinking and human thought. 

* 

Taking nature as exhibiting thought for my guide, it appears to me, that while 

> 
, ... 

human thought is consecutive, Divine thought is simultaneous, embracing at the same 
time and for ever, in the past, the present, and the future, the most diversified 
relations among hundreds of thousands of organized beings, each of which may 
present complications again, which, to study and understand even imperfectly, as 

* 

for instance, Man himself, Mankind has already spent thousands of years. And 
yet, all this has been done by one Mind, must be the work of one Mind only, of 



. 



Compare all the preceding sections, where every 



topic is considered separately 



2 Agassiz, (L.,) Contemplations of God in the 
Kosmos, Christian Examiner, January, 1851, Boston, 



I 

















Chap. I. 



COMBINATION OF RELATIONS. 



131 









Him before whom Man can 




g 



he 



is 



allowed to enjoy in this world 



bow in grateful acknowledgment of the pre- 

not to speak of the promises of a 



future life. 



■ ■ 






in 



I have intentionally dismissed many points in my argument with mere questions, 
order not to extend unduly a discussion which is after all only accessory to 



the plan of my work. 



I have felt justified in doing so because,, from the point 



of view under which my subject 



is 



treated, those questions find a natural solution 



which must present itself to every reader. 



We know what the intellect of Man 



know its creative power, its power of combination, of foresight, 



therefore, prepared to recognize 



a similar 



may originate, we 

of analysis, of concentration ; we are 

action emanating from a Supreme Intelligence to a boundless extent. We need, 

therefore, not even attempt to show that such an Intellect may have originated all 

the Universe contains; it is enough to demonstrate, that the constitution of the 

physical world, and more particularly the organization of living beings in their connec- 



tion with the physical world prove, in 




the existence of a Supreme Being, 



as the Author of all things. 



The task of science is rather to investigate what has 



been done, to inquire, if possible, how it has been done, than to ask what is possible 



for the Deity, as we can 



know that only by what actually exists. 



To attack such 



a 



position, those who would deny the intervention in nature of a creative mind, 

to which they refer the origin of finite beings is by 



must show, that the* cause 
its nature a possible- 



cause, which 



cannot be 



denied of a being endowed with the 



attributes we recognize in 
have proved his existence. 



God. 



Our task is 



therefore completed, as soon as we 



It would, nevertheless, be 




desirable that every 



naturalist, who has arrived at similar conclusions, should go over the subject anew, 
from his point of view and with particular reference to the special field of his 



investigations; for so 



only 



can 



I foresee already that some 



the whole evidence be brought out. 
of the most striking illustrations may be drawn 



from the morphology of the vegetable kingdom, especially from the characteristic 

and systematical combination of different kinds of leaves in the forma- 



■ 



succession 



tion of the 



foliage 



and the flowers of so 



many plants, all of which end their 



development by the production of an endless variety of fruits. The inorganic world, 
considered in the same light, would not fail to exhibit also unexpected evidence 
of thought, in the character of the laws regulating the chemical combinations, the 



action of physical forces, the universal attraction etc., etc. 



Even the history of 



human culture ought to be investigated from this point of view, 
leave it to abler hands to discuss such topics. 



But I must 

























I 



; 





































\ 



i 






1 



■ 



■ 



j: 



: 
































































































































i 




132 



ESSAY ON CLASSIFICATION. 



Part I. 



. ■ 



xr 



• 
■ 



- 



& . 



SECTION XXXII. 



•■ 






I 



F. ;. 



BE CAPITULATION. 



. 



i 



In recapitulating the preceding statements, we may 



present the following con 



i • 



• 



elusions : 

1st. 1 The connection of all these known features of nature into one system ex- 
hibits thought, the most comprehensive thought, in limits transcending the highest 

i 

Wonted powers of man. 

* 

2d. The simultaneous existence of the most diversified types under identical 

■ 

circumstances exhibits thought, the ability to adapt a great variety of structures to 

* 

the most uniform conditions. 

■ 

3d. The repetition of similar types, under the most diversified circumstances, 

; it exhibits thought, proving directly 



shows an immaterial connection between them; it 

how completely the Creative Mind is independent of the influence of a material 

world. 



•• 



of structure in animals otherwise 




4th. The unity of plan in otherwise highly diversified types of animals, exhibits 
thought; it exhibits more immediately premeditation, for no plan could embrace such 
a diversity of beings, called into existence at such long intervals of time, unless it 
had been framed in the beginning with immediate reference to the end. 

5th. The correspondence, now generally known as special homologies, in the details 

disconnected, down to the most minute 

peculiarities, exhibits thought, and more immediately the power of expressing a 
general proposition in an indefinite number of ways, equally complete in themselves, 
though differing in all their details. 

6th. The various degrees and different kinds of relationship among animals which 
can have no genealogical connection, exhibit thought, the power of combining dif- 
ferent categories into a permanent, harmonious whole, even though the material 
basis of this harmony be ever changing. 

i 

7th. The simultaneous existence, in the earliest geological periods in which ani- 
mals existed at all, of representatives of all the great types of the animal kingdom, 
exhibits most especially thought, considerate thought, combining power, premeditation, 

prescience, omniscience. 

8th. The gradation based upon complications of structure which may be traced 



1 









1 The numbers inscribed here correspond to the reader may at once refer back to the evidence, when 
preceding sections, in the same order, so that the needed. 










( 






■ - 



Chap. I. 



RECAPITULATION. 

- 



133 



among 



animals built upon the same plan, exhibits thought, and especially the power 



of distributing harmoniously 



qual 




ifts 



9th. The distribution of some typ 



over the most extensive 



g 



of the sur- 



face of the globe, while others are 

various combinations of these type 

exhibit thought, a close control in 
its inhabitants. 



limited to particular 



phical areas, and the 



into zoological provinces of 
the distribution of the earth 



qual extent, 



surface 



among 



10th. The identity of structure of these types, notwithstanding their wide geo- 



graphical distribution, exhibits thought, 



that deep thought which, 



the more it is 



the less capable of being exhausted, though its meaning at the 



scrutinized, seems 

surface appears at once plain and intelligible to every 



one. 



\ 



llth. The community of structure m 



certain respects of animals otherwise en- 



tirely different, but living within the same geographical area, exhibits thought, and 

of adapting most diversified types with peculiar struc- 



more particularly the power 

r 

tures to either identical or 



to different conditions of existence. 



of special structures observed in animals widely 
the surface "of the globe, exhibits thought, unlimited comprehension, 



12th. The connection, by series, 



scattered over 

and more directly omnipresence 



of mind, and also prescience 



as 



far as such series 



extend through a 



succession of geological ages 



13th. The relation there is between the size 



of animals and their structure and 





form, exhibits thought; it shows that m 

k 

i 

fixedly determined as the qualitative 



nature the quantitative differences are as 



ones. 



14th. The independen 



the size 



of 



exhibits thought 



establishing such close 



ential in themselves and organized beings so 
elements. 



■ 

Imals, of the mediums in which they 

connection between elements so influ- 

little affected by the nature of these 



of specific peculiarities under every 
influences, during each geological period, and under the present 



15th. The permanence 



earth, exhibits thought: it shows, al 
of all finite beings, while eternity 

16th. The definite relations in 
exhibit thought ; ... for all animals 
their very differences 
manner which implies 
uniform conditions 



that limitation in time 



variety of external 
state of things upon 
an essential element 



- 



an 



attribute of the Deity 




which animals stand to the surrounding world, 

respectively, on account of 



g 



togethe 



stand 



a 



different relations to identical conditions of existence, in a 
considerate adaptation of their varied organization to 



these 



17th. The 



relations in which individuals of the same species stand to one an- 



other, exhibit thought, and go far to prove the existence in 
immaterial, imperishable principle, similar to that which 



all living being 



of an 



generally conceded to man 



only 










i 









I 









, 









f 






!: 










































































f 










■/ 






t 






























































1 






! 












134 



ESSAY ON CLASSIFICATION 



Part I. 



18 th. The limitation of the range of changes which animals undergo during their 
growth, exhibits thought ; it shows most strikingly the independence of these changes 
of external influences, and the necessity that they should be determined by a 
power superior to these influences. 

* 

19th. The unequal limitation in the average duration of the life of individuals 
m different species of animals, exhibits thought; for, however uniform or however 
diversified the conditions of existence may be under which animals live together, 

• ■ 

the average duration of life, in different species, is unequally limited. It points, there- 
fore, at a knowledge of time and space, and of the value of time, since the phases 
of life of different animals are apportioned according to the part they have to per- 
form upon the stage of the world. 

20th. The return to a definite norm of animals which multiply in various ways, 

exhibits thought. It shows how wide a cycle of modulations may be included in 

■ 

the same conception, without yet departing from a norm expressed more directly in 
other combinations. 

21st. The order of succession of the different types of animals and plants charac- 
teristic of the different geological epochs, exhibits thought, 
the material world is identical in itself in all ages, ever different types of organized 
beings are called into existence in successive periods. 

22d. The localization of some types of animals upon the same points of the sur- 
face of the 



• • 



It shows,, that while 





consecutive thoug 



e, during several successive geological periods, exhibits thought, 

acting in conformity with a plan 



the 



operations of a 



mind 



laid out beforehand and sustained for a long period 



23d. The limitation of closely allied species to different geological periods, exhib 



■ 

thought; it exhibits the power 



of sustaining nice distinctions 



notwithstanding the 



interposition of g 



disturbances by physical revolutions 




24th. The parallelism between the order of succession of animals and 
in geological times, and the gradation among their living representatives, exhibit 

nature from 
beginning to end, and disclosing throughout a gradual progress, ending with the 



' * 

thought ; consecutive thought, superintending the whole development of 



introduction of man at the 




of the animal creation. 



25th. The parallelism between the order of succession of animals in geological 
times and the changes their living representatives undergo during their embryological 



growth, exhibits thought; the repetition of the 



same 



of thoughts in the ph 



of growth of living animals and the successive appearance of their representatives 



in past 



«■ 



26th. The combination, in many extinct types, of characters which, in later ages 
appear disconnected in different types, exhibits thought, prophetic thought, foresight 
combinations of thought preceding their manifestation in living forms. 












F i _ T #J 





/ 



Chap. I. 



RECAPITULATION. 



135 



27th. The parallelism between the gradation among animals and the changes 

exhibits thought, as it discloses everywhere the 



thej undergo during their growth, 



most intimate connection between essential features of animals which have no 

■ 

necessary physical relation, and can, therefore, not be understood otherwise than 



as established by a thinking being. 



28tk The relations existing between these different series and the geographical 
distribution of animals, exhibit thought ; they show the omnipresence of the Creator. 

29th. The mutual dependence of the 
maintenance, exhibits thought; it displays 
existence, necessary 



animal and vegetable kingdoms for their 
the care with which all conditions of 



to the maintenance of organized beings, have been balanced. 



30th. The dependence of some 



animals upon others or upon plants for their 



existence, exhibits thought; it shows to what degree the most complicated com- 



binations of structure and adaptation can 
conditions which surround them. 



be rendered independent of the physical 



We may sum up 



the results of this discussion, up to this point 



still fewer 



words 



.' 



All organized beings exhibit in 



themselve 



all those categories of structure 



and 



of existence upon which a 



natural 



ystem may be founded, in such 



a manner 



that, in tracing it, the human mind is 
Divine thoughts expressed in nature in 




ilating into human languag 



the 



g 



All these beings do 



sequence 



realities. 

* 

of the continued agency of physical 



causes, but have made their successive 



ppearance upon earth by the immediate 



intervention of the Creator. As proof, I may sum up my 



gument m the fol 



lowing manner 



*- 



The products of what are 



commonly called physical agents are 



ywhere the 



same, (that is, upon 



the whole surface of the globe 



and have always been the 



same (that is, during all geological periods) 



while organized being 



ywher 



different and have differed in all ages. 



Between two such series of phenomena 



there can be no causal or g 
31st. The combination in 



enetic connection. 

time and space of all these thoughtful 



pt 



exhibits not only thought, it shows also premedit 
ness, prescience, omniscience, providence. 

natural connection proclaim aloud the One God, whom man may know, adore 



ition, power, wisdom, greats 
In one word, all these facts in their 



and love 



d Natural History must, in 




ood time, become the analysis of the 



thoughts of the Creator of the Universe, as manifested 



the 




and vegetable 



kingdoms. 



It 



may appear 



strange that I should have included the preceding disquisition 



in that part of my work which is 



headed Classification. Yet, it has been done 









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I ■ 






I . 





























































136 



ESSAY ON CLASSIFICATION. 



Part 1. 



deliberately. In the beginning of this chapter, I have already stated that Classi 



fication seems to me to rest 
npon structure. Animals ar 



upon 



foundation when 



chiefly based 



are linked together as closely by their mode of develop- 
ment, by their relative standing in their respective classes, by the order in which 
they have made their appearance upon earth, by their geographical distribution, and 
generally by their connection with the world in which they live, as by their 



in a 



natural 



anatomy. All these relations should, therefore, be fully expressed 

classification ; and though structure furnishes the most direct indication of some of 

* * 

these relations, always appreciable under every circumstance, other considerations 



our 



ght into the general 




should not be neglected, which may complete 

of creation. 

In characterizing the great branches of the animal kingdom, it is not enough 

to indicate the plan of their structure, in all its peculiarities; there are possibilities 

of execution which are at once suggested to the exclusion of others, and which 

■ 

I 

should also be considered, and so fully analyzed, that the various modes in which 



The 



g 



and 



such a plan may be carried out shall at once be made apparent. 

.... 

character of the general homologies of each type should also be illustrated, as 
well as the general conditions of existence of its representatives. In characterizing 
classes, it ought to be shown why such groups constitute a class and not merely 
an order, or a family ; and to do this satisfactorily, it is indisp ensable to trace the 



them 



It 



special homologies of all the systems of organs which are developed in 
is not less important to ascertain the foundation of all the subordinate divisions 
of each class; to know how they differ, what constitutes orders, what families, what 
genera, and upon what characteristics species are based in every natural division. 

* 

This we shall examine in the next chapter. . 





















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PART I. OF THE FIRST VOLUME OF THE 








ONTRIBUTIONS 



TO THE 














NATURAL HISTORY OF THE UNITED STATES 











OF 



I 









A. 



/ 



BY 



L. 



A G A S S I Z 






*V. K: 








V_V„ 























Chap. TI 



BRANCHES OF THE ANIMAL KINGDOM, 



137 



"i 












I 












CHAPTER SECOND. 



LEADING GROUPS OF THE EXISTING SYSTEMS OF ANIMALS. 

* 



SECTION I. 









! I 


















1 ■ 





GREAT TYPES OR BRANCHES OF THE ANIMAL KINGDOM. 






The use of the terms types 
ly stems of Zoology and Botany 



classes, orders, families, g 



and 



species in the 



so universal, that it would be natural 



that their meaning 
this 



and extent are well determined and generally understood 



suppose 
; but 



IS so 



far 



from being the case 



that it may, on the contrary, be said, there is 



no 



ubject in Natural History respecti 



which there exists more 



certainty and 



a 



g 



want of precision 



Indeed, I have failed to find anywhere a definition 



of the character of most of the more comprehe 



of these divisions, while the 



current views respecting g 



and species are very conflicting. Under these cir- 



cumstances, it has appeared to me particularly desirable, to inquire into the founda- 
tion of these distinctions, and to ascertain, if possible, how far they have a real 



existence. And while I hop 



the results of this inquiry may be welcome and 



■ 

satisfactory, I am 

conceptic 



a clear 



free to confess that it has cost me years of labor to arrive at 
of their true character. 



It is such a 



universal fact in every sphere of intellectual activity, that 



pr 



should be surprised to find zoologists 

vegetable kingdoms, 



tice anticipates theory, that no philosopher 
have adopted instinctively natural groups, in the animal and 
even before the question of the character and of the very existence of such 
groups in nature was raised. Did not nations speak, understand, and write Greek, 
Latin, German, and Sanscrit before it was even suspected that these languages 
and so many others were kindred? Did not painters produce wonders with 
colors before the nature of light was understood ? Had not men been thinking 
about themselves and the world before logic and metaphysics were taught in schools ? 

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138 



4 



ESSAY ON CLASSIFICATION. 



. - 



Part I. 



Why 
betw< 



should not observers of nature have appreciated rightly the relationship 



animals or plants before getting a 



scientific clue to the classifications they 



were led to adopt as practical 



Such considerat 



above all others, have guided and 



was 



for the meaning of all these system 



so different 



aged me while I 

from the other in 



their details, and yet so 

of our science shows how 




some 



similar in some of their general features. The history 

of the principles, which obtain to this day, 

Aristotle, for instance, knew 

already the principal differences which distinguish Vertebrata from all other animals, 



have been acknowledged by all reflecting naturalists 



and his distinction of M 



and Aneima 



1 



ponds 



tly to that of Verteh 



and Invertehrata of Lamarck, 2 or to that of Flesh- and Gut-Ammals of Oken, 3 or, to that 



of Myeloneura 
with the pro 



and Gangk 



of Ehrenberg; 4 and one who is at all familiar 



pects 



of science at different periods, can but smile at the claims to 
!ty or originality so frequently brought forward for views long before current 

Here for instance, is one and the same fact presented in different 

native fluid. 



among men 



first, by Aristotle with reference to the character of the for 



next by Lamarck with reference to the general frame, for I will do Lamarck 



the iusti 



to believe, that he did not unite the Invertebrata simply b 



they 



have no skeleton, but because of that something, which even Professor Owen fails 

fen Invertebratalcon- 



to express, 5 and which yet exists, the one 



ty of the body 



tainino- all organs, whilst Vertebrata have one distinct cavity for the centres of the 



ystem and another for the organs of the vegetative life 



This acknowledg 



ment is due to Lamarck as truly as 
him of having denied the Invertebrata 



it would be due to Aristotle not to accuse 



any 



fluid 



g 



the office of the blood 



tho ugh he 

that there moves a 



calls them Aneima ; for he knew nearly as well as we now know 



nutritive fluid in their body 



generally denied him, because he had no correct knowledg 



gh that information is 
> of the circulation of 



the blood 



A 



o 



when Oken speaks of Flesh-Animals he does not mean that Vertebrates 



consist of 



g 



but flesh, or 



that the Invertebrates have no muscul 



fibres 



* 

but he brings prominently before us the 



presence, m 



the former, of those masses 



forming mainly the bulk of the body, which consist of flesh and bones, as well 

and constitute another of the leading features distinguishing 



as blood and nerves 



Vertebrata and Invertebrata. Ehrenberg presents the same relations b 



the 



same beings as expressed by their nervous system 



If we 



take the expressions 



1 Histor. Anim., Lib. I., Ch. 5 and 6. 

2 Anim. Vert., 2d edit., vol. 1, p. 313. 

3 Naturphilosophie, 3d edit., p. 400. 



Menschen 



a large sheet, folio. 



Comparat. Anat. of In v., 2d edit., p. 1 1 










I 



[ 



' . 



»». • . 




Sv 







■ 



I - 















Chap. II. 



BRANCHES OF THE ANIMAL KINGDOM. 



139 



of Aristotle, Lamarck, Oken, and Ehrenberg together, have we not, as characterist 



of their systems 



very words by which every 



distinguishes the most promi 



nent features of the body of the higher animals, when speaking of blood 



of blood and bones, or of havin 



n 



flesh and nerve ? 



* 

Neither of these observers has probably been conscious of the identity of his 



classification with that of his predecessors 



indeed, should we consider either 



of them 



perfluous, inasmuch as it makes prominent, features more or less differ 



ent from those insisted upon by the others 



nor 



ght any one to suppose that 



with all of them the field is exhausted, and that there is no more room for new 

4 

systems upon that very 

they will have opportunities to know more upon these top 



first distinction among animals 



As 



g as men inquire 



than those 



have 



gone before them 



inexhaustibly rich is nature in the innermost diversity of her 



treasures of beauty, order, and 



So 



stead of discarding all 



intelligence. 

the systems which have thus far had little or no 



influence upon the prog 



of science, either because they are based up 



prm 



pies not generally acknowledged or considered worthy of confidence, I haye care- 



fully studied them with the view 



of 



g whatever there may be true in 



them from the stand-point from which their authors have considered the animal 
kingdom* and I own that I have often derived more information from such a careful 



considerati 
It was 



n than J had at first expected. 

not indeed by a lucky hit, nor by one of those 



unexpected apparitions 
which like a revelation, suddenly break upon us and render at once clear and 

* 

comprehensible what had been dark and almost inaccessible before, that I came to 
understand the meaning of those divisions called types, classes, orders, families, gen- 



and species so long admitted in Natural History 



the b 



of 



every system 



and yet so 



o-enerally considered as mere artificial devices to facilitate our studies 



For years I had been laboring under the impression that they are founded in 
nature before I succeeded in finding out upon what principle they were really based. 



I soon perceived, however, that the g 



obstacle in the 



way 



of 



their true significance lay 
and application of these terms 



the discrep 



among different author 



their 



mg 
use 



Different naturalists do not call by the same name 



groups 
sub 



6 



of the same kind and the same extent: some call genera 

others call tribes, or even families, what are called g 



what others call 
mera by others; 



1 By way of an example, I would mention the different from what is observed in any of the Inver- 

mode of reproduction. The formation of the egg in tebrata, that the animal kingdom, classified according 

Vertebrata ; its origin, in all of them, in a more or to these facts, would again be divided into two great 

less complicated Graafian vesicle, in which it is groups, corresponding to the Vertebrata and Inverte- 

nursed ; the formation and development of the embryo brata of Lamarck, or the Flesh- and Gut-Animals of 

up to a certain period, etc., etc., are so completely Oken, or the Eneima and Aneima of Aristotle, etc. 








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•v 



140 



ESSAY ON CLASSIFICATION. 



Part I. 



even the names of tribe and family have been applied by some to what other 



■ 

call sub-g 



some have called families what others have called orders; some 



consider as orders what others have considered as classes; and there 
of some authors which are considered as classes by others. Finally 



and limitation of these 



well 



the manner in which they 






ether, under general heads, there is found the same diversity of opinion 



even genera 
the number 

are grouped 

It is. 



if their true relation 



one another 



■ 

nevertheless, possible, that under these manifold names, so differently applied, groups 
may be designated which may be natural, even 
have thus far escaped our attention. 

It is already certain that most, if not all 



g 



g 



in the limitation 



of some groups at least, under whatever name they may call them, and however 
much they would blame one another for calling them so, 



or otherwise. I can there 



ques 



fore no longer doubt that the controversy would be limited to definite 
tions, if naturalists could only be led to an agreement respecting the real nature 
of each kind of groups, I am satisfied, indeed, that the most insuperable obstacle 

to any exact appreciation of this subject lies in the fact, that all naturalists, with- 



out i 

them 



pti 



consider these divisions, under whatever name they may desig 



as 



ctly 



subordinate one to the other, in such a manner, that their differ 



ence is only dependent upon 



their extent; the class being considered as the more 



comprehensi 



the 



g 



as 



division, the order as the next ext( 
still more limited, and the species 



as 



3, the family as more limited, 
the ultimate limitation in a 



natural 



g 



of living b 



© 



so that all these groups would differ only by 



the quantity of their characters, and not by the quality, as 



if the elements of 



structure in 



animals were all of the same kind 



as 



if the form, for instance, was 



an 



organic element of the same kind as the complication of structure, and 



as 



if 



the degree of complication 



implied necessarily one plan of structure to the exclu- 
sion of another. I trust I shall presently be able to show that it is to a neglect 
of these considerations that we must ascribe the slow progress which has been 
made in the philosophy of classification. 

Were it possible to show that all these groups do not differ in quantity, and 

but are based upon 
would be called genera by all, whether 



are not merely divisions of a wider or more limited range, 

different categories of characters, genera 

they differ much or little one from the other, and so would families be called fam- 

* 

ilies, orders be called orders, etc. Could, for instance, species be based upon absolute 
size, genera upon the structure of some external parts of the body, families upon 
the form of the body, orders upon the similarity of the internal structure, or the 

m 

like, it is plain that there could not be two opinions respecting these groups in 

in nature, 



any class of the animal kingdom. But as the problem is not so 



simple 



it was not until after the most extensive investigations, that I seized the clue to 




( 



























I I <w 





















Chap. II. 



BRANCHES OF THE ANIMAL KINGDOM. 



141 



- 



■ 



guide me through this labyrinth, 
been disputing; and are 



I knew, for instance, that though naturalists have 



still 



disputing, about 



species and genera, they all distin- 
guished the things themselves in pretty much the same manner. What A would 



B might call a sub- 



call a species, B called only a variety or a race; but then 
genus the very same aggregate of individuals which A called a species; or what 
A called a genus was considered by B as a family or an order. Now it was this 
something called no matter how, for which I tried to find out characters which would 
lead all to call it by the same name ; thus limiting the practical difficulty in the 

application I 

allowing it to be an eternal contest about mere nomenclature. 



of the name to a question of accuracy in the observations, and no longer 



At this stage of my investigation 



it struck me, that the character of the writ- 



ings of eminent 
are authors, and 
knowledge in 



naturalists might throw some light upon the subject itself. There 

of the most celebrated contributors to our 



among them some 



Natural History, who never busied themselves with classification, or 
paid only a passing notice to this subject, whilst they are, by universal consent, 
considered as the most successful biographers of species; such are Buffon, Beau- 

Roesel, Trembley, Smeathman, the two Hubers, Bewick, Wilson, Audubon, 



mur 



Naumann, etc. 



Others have applied themselves almost exclusively to the study of 






genera 
and 



Latreille is the most prominent zoologist of this stamp; whilst Linnseus 

botanists for their characteristics of genera, or at 



Jussieu stand highest among 



least for their early successful attempts at tracing the natural limits of genera. Bota- 
nists have thus far been more successful than zoologists in characterizing natural 
families though Cuvier and Latreille have done a great deal in that same direction 

whilst Linnaeus was the first to introduce orders in the classification of 
As to the higher groups, such as classes and types, and even the orders, 

which have followed all the natu- 



in Zoology, 



animals. 



we find again 

ralists of this century. 



Cuvier leading the 



procession, in 



Now let us inquire what these men have done in particular to distinguish them- 
selves especially, either as biographers of species, or as characterizers of genera, of 
families, of orders, of classes, and of types. And should it appear that in each case 
they have been considering their subject from some particular point of view, it strikes 



me 



that what has been acknowledged unconsciously as constituting the particular 



emi- 



nence or 



distinction of these men, might very properly be proclaimed, with grate- 
ful consciousness of their services, as the characteristic of that kind of groups which 
each of them has most successfully illustrated; and I hope every unprejudiced natu- 



ralist will agree with me in 
As to the highest divisions 



this respect. 



of 



the animal kingdom, first introduced 



by Cuvier 
under the name of embranchements, (and which we may well render by the good old 

English word branch,) he tells us himself that they are founded upon distinct plans 



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142 



ESSAY ON CLASSIFICATION 



Part I 



of structure 



were 



distinct moulds or forms. 1 Now there 



b 



no reason why we should not all ag 



to designate 



as typ 



all such 



g 



divisions of the animal kingdom as are constituted 



:an certainly 
or branches 
a special 




, 2 if we should find practically that such groups may be 



upon 
aced in nature. 



Those who may not see them may deny their existence; those who recog 
them may vary in their estimation of their natural limits; 



science, agree to call 



greatest benefit of 

founded upon a special plan of 

and if there are still differences of opinion among naturalists respectm 

let the discussion upon this point be carried on with 



but all can, for the 
any group which seems to them to be 
type or branch of the animal kingdom'; 

t their limits. 



the understanding that typ 



be characterized by different plans of 



and 



by special anatomical 



peculiarities 



Let us avoid confounding the idea of plan with that of 



plication 



of structure, even though Cuvier himself has made this mistake here and there in 

his classification. 

The best evidence I can produce that the idea of distinct 




of structure 



is the true pivot upon which the ' natural limitation of the branches of the animal 
kingdom is ultimately to turn, lies in the fact that every great improvement, 



acknowledged by all as such, which these 

consisted in the removal from among each, of such 



primary divisions have undergon 



has 



groups as had been placed 



with them from other considerat 



than those of a peculia 




or in conse- 



quence of a 



want of information respecting their true plan of structure. 



Let 



examine 



this point within limits no longer controvertible 



Neither Infusoria nor 



Intestinal Worms are any longer arranged by competent naturalists among 



Why they have been removed, may be considered elsewhere 



but it was 



Kadiata. 
certainly 



not because they were supposed to agree in 



the plan of their structure with the 



1 It would lead me too far were I to consider old expressions, in a somewhat modified sense, is found 

here the characteristics of the different kingdoms of preferable to framing new ones. I trust the value of 

Nature. I may, however, refer to the work of I. the following discussion will be appreciated by its 

Geoffkoy St. Hilaire, Histoire naturelle generate intrinsic merit, tested with a willingness to understand 

des regnes organiques, Paris, 1856, 8vo., who has dis- what has been my aim, and not altogether by the rela- 

cussed this subject recently, though I must object to tive degree of precision and clearness with which I 

alone. may have expressed myself, as it is almost impossible, 

It is almost superfluous for me to mention here in a first attempt of this kind, to seize at once upon 



to-dom for Man 



that the terms plan, ways and means, or manner m 



the form best adapted to carry conviction. I wish 



which a plan is carried out, complication of structure, also to be understood as expressing my views more 

form, details of structure, ultimate structure, relations immediately with reference to the animal kingdom, 

■ 

of individuals, frequently used in the following pages, as I do not feel quite competent to extend the inquiry 

are taken in a somewhat different sense from their and the discussion to the vegetable kingdom, though 

is always necessary when new I have occasionally alluded to it, as far as my in- 



meaning, as 



usual 

views are introduced in a science, and the adoption of formation would permit. 



• 










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p^^^^^^^^^ 






Chap. II. 



BRANCHES OF THE ANIMAL KINGDOM. 



143 



true Kadiata, that C 



allowed himself 



dep 



placed them in that division, but simply becaus 
from his own principle, and to add another consider 



he 



besides the plan of structure, 



as 



char 



of Kadiata, the 



pposed absence of 



a 



nervous system, and the g 



simplicity of structure of these animals; as if 

an of structure. 




simplicity of execution had any necessary connection with the 

Another remarkable instance of the generally approved removal of a class from 

one of the types of Cuvier to another, was the transfer of the Cirripeds from 

Articulata. Imperfect knowledge of the plan 

of structure of these animals was here the cause of the mistake, which was cor- 
rected without any opposition, 



among the Mollusks to the branch of 



>n, as soon as they became better known. 

* 

From a comparison of what is stated here respecting the different 




of 



structure, characteristic of the primary divisions of the animal kingdom, with what 

below about classes and orders, it will appear more fully, that it 



I have to say 



is 



portant to make a distinctions b 




is 



or simplicity 



ner in which that 

relative perfection 

structure should be the leading characteristic of these 

yet follow, without further examination, that the four g 



the plan of a structure and the man- 

its 



carried out, or the degrees of its complication and 



But even after it is understood that the plan of 

primary groups, it does not 
eat branches of the animal 



kingdom, first distinguished by C 



to be considered as the primary divisions 
It will still be necessary, by a careful 



which Nature points out as fundamental 

and thorough investigation of the subject, to ascertain what these primary groups 

are; but we shall have gained one 



s 



point with reference to our systems, that what- 



ever these primary groups, founded upon different plans, which 



may 



be, when they are once 



defined, or whilst they are admitted as the temporary ex- 



pression of our present knowledge, they should be called the branches of 



animal 






dom, whether they be the Vertebrata, Articulata, Mollusca, and Kadiata of Cuvier 



or 



Artio 



Actino 



and Amorphoz 



of Blainville, or the Verteb 



and Invertebrata of Lamarck. The special inquiry into this point must be left for 



a special paper 



I will 




add, that I am daily more satisfied, that, in their 



general outlines, the primary divisions of Cuvier are true to nature, and that never 
did a naturalist exhibit a clearer and deeper insight into the most general relations 



of animals than Cuvier, when he perceived, not 




that these primary groups are 



founded upon differences in the plan of their structure, but also how they are 



tially 



elated to one another. 



Though the term tyt 



is generally employed to desig 



the great fundamental 



divisions of the animal kingdom, I shall not use it in future, but prefer for it the 



term branch of the animal kingdom, b 



the term type is employed in too 



many different acceptations, and quite as commonly to designate any group of any 
kind, or any peculiar modification of structure stamped with a distinct and marked 




!! 









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I 
























:: 



* 





m v 




144 



ESSAY ON CLASSIFICATION 



Part I 



the primary divisions of the animal kingdom 



We 



tyP 



family types, ordinal typ 



character, as to designate 

speak, for instance, of specific types, g 

classic types, and also of a typical structure. The use of the word typ 

sense is so frequent on almost every page of our systematic works, in Zoology 

re anatomy, that it seems to me desirable, in order 



m 



this 



and in treatises of 



parati 



to avoid every possible equivocation in the desig 



of the most important g 



divisions among 



animals, to call them branches of the animal 



dom 



p rimaryi 

rather than types. ■'..-.» 

That, however, our systems are more true to nature than they are often sup- 
posed to be, seems to me to be proved by the gradual approximation of scientific 



men to each other, in their 



and in the forms by which they express those 



results. The idea which lies at the foundat 



of the 



g 



primary divisions 



of the animal kingdom is, the most general conception possible in connection with 



the plan of a definite creation ; these divisio 



therefore the most comprehensiv 



.- 

of all, and properly take the lead in a natural classificatio 



as 



presenting the 



first and broadest relations of the different natural groups of the animal kingdom 



the 



g 



formula which they each obey. What we call branches expresses, in 



fact, a purely ideal connection between animals, the intellectual 
unites them in the creative thought. 



pt 



which 



It seems to me that the more we examine 



the true significance of this kind of groups, the more we shall be convinced that 
they are not founded upon material relations. 



The lesser divisions which succeed 



next are founded upon special qualifications of the plan, and differ one from the 
other by the character of these qualifications. 



Should it be found that the features 



in the animal kingdom which 



the 




a 

of structure, extend 



the larg 



divisions, are those which determine their rank or 



ipect 



standing, it would 



appear natural to consider the orders as the second most important category 



the 



g 



of animals. Exp 



however, shows that this is not the case 



that the manner in which the plan of structure is executed leads to the distinction 
of more extensive divisions (the classes) than those which are based upon the com- 
plication of structure (the orders). As a classification can be natural only as far 
it expresses real relations observed in nature, it follows, therefore, that classes take 
the second position in a system, immediately under the branches. We shall see 
below that orders follow next, as they constitute naturally groups that are more 



comprehensive than families, and that we are not at liberty to invert their respec- 
tive position, nor to transfer the name of one of these divisions to the other, at 



our own pleas 



as so many naturalists 



are constantly doing 



* 



V 






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m 








^^■^^W ^^^^^^ ■ 



/ 



Chap. II 



CLASSES OF ANIMALS. 



145 



SECTION 



II. 










i 



it 









I 



T 






■ 












CLASSES OF ANIMALS. 



Before Cuvier had shown that the whole 



animal kingdom is constructed 



upon 



four different plans of structure, classes were the highest groups acknowledged in 
the systems of Zoology, and naturalists very early understood upon what this kind 
of division should be founded, in order to be natural, even though in practice 
they did not always perceive the true value of the characters upon which they 
established their standard of relationship. Linnaeus, the first expounder of the 
system of animals, already distinguishes, by anatomical characters, the classes he 
has adopted, though very imperfectly; and ever since, systematic writers have aimed 
at drawing a more and more complete picture of the classes of animals, based 



upon 



a more or 



less extensive investigation of their structure. 

of 



Structure, then, is the watchword for the recognition of classes, and an accurate 
knowledge of their anatomy the surest way to discover their natural limits. And 
yet, with this standard before them, naturalists have differed, and differ still greatly, 
in the limits they assign to classes, and in the number of them they adopt. It 
is really strange, that, applying apparently the same standard to the same objects, 
the results of their estimation should so greatly vary ; and it was this fact which 
led me to look more closelv into the matter, and to inquire whether, after all, 
the seeming unity of standard was not more a fancied than a real one. Structure 

* 

may be considered from many points of view: first, with reference to the plan 
adopted in framing it; secondly, with reference to the work to be done by 
to the ways and means employed in 




building it up ; 



degrees 



and 
thirdly, with reference to the 

of perfection or complication it exhibits, which may differ greatly, even 

though the plan be the same, and the ways and means employed in carrying out 

such a plan should not differ in the least; fourthly, with reference to the form 

of the whole structure and its parts, which bears no necessary relation, at all events 

no very close relation, to the degree of perfection of the structure, nor to the 



manner in which its 




is executed, nor to the 




itself. 



between Bat! 
Worms, may 



and Birds, between Whales and Fishes 



as a comparison 



between Holothuria 



and 




show 



fifthly and lastly, with reference to its last finish to 



the execution of the details in the individual parts. 

+ 

It would not be difficult to show, that the differences which exist ai 
naturalists in their limitation of classes have arisen from an indiscriminate 
sideration of the structure of animals, in all these different points of view, and an 

19 



long 
con- 














































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1 


















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\ 







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146 



ESSAY ON CLASSIFICATION. 



Part I. 



, 



equally indiscriminate application of the results obtained, to characterizing classes. 
Those who have not made a proper distinction between the plan of a structure 
and the manner in which that plan is actually executed, have either overlooked 



the importance of the g 



fundamental divisions of the animal kingdom, or they 



have unduly multiplied the number of these primary 
tinctions upon purely anatomical considerations, that is 

- 

in the character of the general 
ment of that plan. 




Those 



g 



divisions, basing their dis- 

to say, not upon differences 
ti of structure, but upon the material develop- 
who have confounded the complication of the 



with the ways and means by which life is maintained 



through 



any g 



combination of systems of org 



have failed in establishing a proper difference 



betw 



class and ordinal characters, and have ag 



and again raised 



ders to 



the rank of classes. For we shall see presently, that natural orders must be based 
upon the different degrees of complication of structure, exhibited within the limits 
of the classes, while the classes themselves are characterized by the manner in 

of the type is carried out, that is to say, by the various com- 

vesiof 




which the 

binations of the systems of org 



g the body of the representat 



any of the great types of the animal kingdom ; or perhaps, still more distinctly, 
the classes are characterized by the different ways in which life is maintained, and 
the different means employed in 



establishing these 



ways 



An 



to show tl 
characters. 



distinction impli 



a 



example will suffice 
marked difference between class and ordinal 



Let us compare the Polyp 



and 



Acalephs as two classes, without allowing our 



selves to be troubled by the different limits assigned to them by different authors. 
Both are constructed upon the same plan, and belong, on that account, to the type 
of Radiata. In establishing this fact, we do not consider the actual structure of 

- 

these animals, whether they have a nervous system or not, whether they have 

ms of senses or not, whether their muscles are striated or smooth, whether 



g 



they have a solid frame or an 

one opening or two < 



:ly soft body, whether their alimentary 



■ty 



has 




pposite openings, whether it has glandul 



annexes 



or 



not, whether the digested food is distributed in the body one way or another 



whether the undigested materials are rejected through the mouth or not, whether 
the sexes are distinct or not, whether they reproduce themselves only by eggs, or 
by budding also, whether they are simple or not : all we need know, in order to 



refer them to the branch of Radiata, is whether the 




of their 



exhibits 



a general radiated 



gement 



or 



not. 



But, when we would distinguish Polyp 



Acalephs, and Echinoderms as 



classes, or rather, when we would ascertain what 



are 



the classes among Radiata, and how 



many there are, we 



must inquire 



the 



manner in 



which this idea of radiation, which lies at the foundation of their pla 



of structure, is 



tually expressed in all the animals exhibiting such a plan, and 






■ 









■ 










V 




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i r. 



1 









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Chap. II. 



CLASSES OF ANIMALS 



147 



we 



find 




that while in some 



(th 



Polyp 



the 



body exhibits a large cavity 



divided by radiating partit 



into 



number of chamb 



which han 



a sac 



( the dige 
the main 



agency 



cavity,) open below, so as to pour freely the digested food into 
ty, whence it is circulated to and fro in all the chambers, by the 

ain and full 



of vibrating cilia ; 



in others, (the Acalephs,) the body is 




not to be compared to a hollow sac, traversed only in its thickness by radiating 
tubes, which arise from a central cav 



ty, (the digestive cavity,) without a free com 



munication with one another for their 



whole length 



(the Echinoderms 

cavity in which a 

Without givin 



there 



gh 



etc., etc., while in others still, 
gid envelope to the body, inclosing a large 



contained a variety of distinct systems of organs, etc. 

here a full description of these classes, I only wish to show 



that what truly characterizes them, is not the compl 



of their structure, 




Hydroid Medusse are hardly more complicated in their structure than Polyp 
the manner in which the 



but 




in of Eadiata is carried out, the ways in which life 
maintained in these animals, the means applied to this end ; in one word, the 
combinations of their structural elements. But the moment we would discern 



is 



. 



what are the orders of these classes, these considerations 
structure has to be viewed in a different light; it 



no longer suffice; their 



is now 



the compl 



of 



these 



pparatus which may guide 



as orders, differ, the first by having 



Actinarians and Halcyonarians among Polypi, 

■ 

usually indefinite number of 



a 



larger 



and 



simple tentacles, an equally large 



number of 



nal par 



etc., while in 



Haley 



the 



g 



tentacles are lobed and complicated, and all the parts are 



combined in pairs, in definite numbers, etc., differences which establish a dis- 

ling the latter a higher rank than 



tinct standing between them in their class 
the former. 



g 



It follows, then, from the preceding remarks, that 



to be distinguished 



by the manner in which the plan of their type is executed, by the ways and 



means by which this is 



done, or, in other words, by the combinations of their 



structural elements, that is to say, by the combinations of the different systems of 

We need not consider here 
nor the ultimate details. 



build in 



the 



organs Duuaing up tne body of tneir repr 



their 



the various forms under wh 



the structure is embodied 



nor the last finish which this structure may exhibit, as a moment's reflection will 



structural details can ever be characte 



convince any one that neither form nor 

of classes. 

There is another point to which I would call attention, respecting the charac- 
teristics of classes. These great divisions, so important in the study of the animal 
kingdom, that a knowledge of their essential features is rightly considered as the 



primary object of all investigations in comparative anatomy, are generally repre- 
sented as exhibiting each some essential modification of the type to which they 



111 






I 






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> *4 *Sk- **": 








II 









II 



1 








I 





















J 

] 











■MMB 















148 



ESSAY ON CLASSIFICATION. 



Part 1. 



belong 



This 



view 



g 



I consider to be a mistaken appreciation of the facts 



to which Cuvier has already called attention, 
unnoticed. 1 



though his 



warning has remained 



1 There is in reality no difference in the plan of animals belonging to 
different classes of the same branch. The plan of structure of Polypi is no more 
a modification of that of Acalephse, than that of Acalephse or Echinoderms is a 

modification of the 



' Ft 




of Polyps ; the plan is 



ctly the same in all three 



it may be represented by one simple diagram, and may be expressed in one 
word, radiation: it is the manifestation of one distinct, characteristic idea 



agle 
But 



this idea is exhibited 



nature under the most different forms, and expressed in 



different ways, by the most diversified combinations of structural modifications and 
in the most varied relations. In the innumerable representatives of each branch 

» 

of the animal kingdom, it is not the 

* 

this plan is executed. In the same manner as the variations played by a skilful 




that differs, b 



the manner in which 



artist upon the simplest tune are not modificat 



of the tune itself, but 



uly 



different expressions of the same fundamental harmony, just so are neither the classes, 
nor the orders, nor the families, nor the genera, nor the species of any great type, 



modifications of its pla 



but 




its different expressions, the different ways in 



which the fundamental thought embodied in it is manifested in a variety of living 

i 

beings. 

■ 

In studying the characteristics of classes we have to deal with structural features, 

their relations to the branches of the animal kingdom to 



while in investigating 



which they belong, 



we 



have 




to consider the general plan, the framework 



as it were, of that structure, not the structure itself. This distinction leads to 



an important practical result 



Since, in the b 



of this century, naturalists 



have b 



a 



under the lead of the German physiophilosophers, to comp 



more 



closely the structure of the different classes of the animal kingdom, points of 



resemblance have been noticed between them which had 



rely escaped the atten- 



tion of earlier 



g 



structural modifications have been identified, which, at 



first, seemed to exhibit no similarity, so much so, that step by step these com- 
parisons have been extended over the whole animal kingdom, and it has been 



ted, that, whatever mav be the apparent differences in the organization of ani- 



mal 



they should be considered as constructed of parts essentially identical 



This 



assumed identity of structure has been called homology. 2 But the progress of 

comparisons within narrower limits, and it 

>us only as far as they belon 



science is 



gradually restricting these 



now, that the 



of animals is homolog 



g 



appears 

to the same branch, so much so, that the study of homologies is likely to afford 

one of the most trustworthy means of testing the natural limits of any of the 






1 Cuvier, Regn. An., 2d edit., p. 48 



2 See Chap. I., Sect. 5 









" 



^^v 





!V' 













1 









v 



• I 



H 






Chap. II. 



CLASSES OF ANIMALS. 



149 















i 






\ 



great types of the animal kingdom. While, however, homologies show the close 
similarity of apparently different structures and the perfect identity of their plan, 

■ 

within the same branches of the animal kingdom, yet, they daily exhibit 



more 



and more striking differences, both in plan 

themselves, leading to the 



and structure, between the branches 



suspicion that systems 



of organs 



which are generally 



considered as identical in different types, will, in the end, prove essentially different, 
as, for instance, the so-called gills in Fishes, Crustacea, and Mollusks. 

already that the gills of Crustacea are 
and the so-called lungs of certain spiders, in 



It requires no great penetration to see 



homologous with the trachese of Insects 



the same manner as the gills of aquatic Mollusks are homologous with the so-called 

Now, until it can be shown that all 



lungs of our air-breathing snails and slugs. 



their muscular system, to their digestive 

It would not 



these different respiratory organs are truly homologous, I hold it to be more natural 
to consider the system of respiratory organs in Mollusks, in Articulates, and in Verte- 
brates, as essentially different among themselves, though homologous within the limits 
of each type ; and this remark I would extend to all their systems of organs, to their 

■ 

solid frame, to their nervous system, to 

apparatus, to their circulation, and to their reproductive organs, etc. 

be difficult to show now that the alimentary canal with its glandular appendages, 

in Vertebrata, is formed in an entirely different way from that of Articulates or 

Mollusks, and that it cannot be considered as homologous in all these types. And 

if this be true, we must expect soon an entire reform of our methods of illustrating 

comparative anatomy. 

Finally, it ought to be remembered, in connection 
well as that of other groups, that the amount of difference 



with the study of classes as 



g 



betw 



two di\ 



is nowhere the same 



c 



ome 



features in nature seem to be 



any 
sted 



-epeated more frequently and more 
number of representatives. This 
qual weight of different groups, so evident everywhere in the animal kingdom, 
ght to make us more cautious in estimating their natural limits, and prevent us 



upon with more tenacity than others, to be 
widely, and to be impressed upon a larger 

groups, so evident 



fro 



g 



an 



undue value to the differences observed between living bein 



g 



never ovt 
variations. 



g apparently g 



discrep 



nor underrating 



gly trifling 



The 



right path, however, can only 



be ascertained by extensive inves- 



gations, made with special reference to this point. 
Everybody must know that the males and females of some species differ much 

from the other than many species do, and yet the amount of difference 

constantly urged, even without a preliminary investi- 



more one 



observed between species is 
Ration, as an a 




gument for distinguishing them. These differences, moreover 



are 



not 



nly quantitative, they are to a still greater extent also qualitat 



In the 









'( 












^ 








































I 




























































I 






* 



150 



ESSAY ON CLASSIFICATION. 



Part I. 



same manner 



do- 



g 



differ more or less one from the other, even in the same 



family; and such inequality, and not an equable apportionment, is the norm through 



out nature. In classes, it is not only exhibited in the 
also, to an extra* 



ety of their forms, but 
rdinary extent, in their numbers, as, for instance, in the class of 

Insects compared to that of Worms or Crustacea. The primary divisions of the ani- 

HArticulata arefcylfar 

the most numerous branch of the whole animal kingdom; their number exceeding 
greatly that of all other animals put together. 



mal kingdom differ in the same manner one from the other 



Such facts are in themselves sufficient 



to show how artificial classifications must be which admit 
and the same kind of divisions for all the types 




the same number 



of the animal kingdom 



SECTION III. 



ORDERS AMONG ANIMALS 



Great as is the discrepancy between naturalists respecti 



the number and limits 



* * 

of classes in the animal kingdom, their disagreement in regard to orders and families 
is yet far greater. These conflicting views, however, do not in the least shake 

my confidence in 
thoughtful considerations 

one 




the existence of fixed relations between animals, determined 

I would as soon cease to believe in the existence of 

God, because men worship Him in so many different ways, or because they 
m worship gods of their own making, as distrust the evidence of my own senses 
pecting the existence of a preestablished and duly considered system in nature, 



the 



arrangement of which preceded the creation of all things that exist. 
From the manner in which orders are generally characterized and introduced 
into our systems, it would seem as if this kind of groups were interchangeable 



with families 



Most botanists make no difference even b 



orders and families 



and take almost univ< 
extensively admitted a 



have 



more 



as superior, others place families higher; 
time distinguishing families, and vice versd 
without admitting orders 
orders and families. 



-sally the terms as mere synonyms. Zoologists 
difference between them, but while some consider the orders 

; others admit orders without at the same 




introduce families into their classification 
others still admit tribes as intermediate groups between 

may 
The 



A glance at any general work on Zoology or Botany 



the student how utterly arbitrary the systems are in 



this 



pect 



is% 



animal of Cuvier exhibits even the unaccountable feature, that while orders 



• ■. 



• 









■ 











fc^*» ^^l_l"i* 




' ■. 



" 



. 






■ 




>•.** 





Chap. II 



ORDERS AMONG ANIMALS. 



151 



and families are 



oduced in some 



and even some exhibit 




a succession of g 



ly orders are noticed in others, 1 
ra under the head of their class 



further 



grouping among 



without any 

fications exhibit the most peda 



them into orders or families 



Other classi- 



uniformity of a reg 



succession in each class, 



of sub-classes, orders, sub-orders, families, sub-families, tribes, sub-tribes, g 



sub 



g 



divisions, sections, and sub-divisions, sub 



etc., but bear upon their 



face, that they are made to suit preconceived ideas of regularity and symmetry in 
the system, and that they are by no means studied from nature. 

To find out the natural characters of orders from that which really exists in 



nature, I have considered attentiv 
orders are admitted and apparently 



ly the different systems of Zoology in which 
considered with more care than elsewhere, and 



in particular the 




'Natures of Linnseus, who first introduced in Zoology that 



kind of groups, and the works of C 



which orders are frequently charac 



terized with unusual precision, and it has appeared to me that the leading idea 



prevailing 



ywher 



pecting order 



random, is that of a definite rank among them, 

tive standing of these divisions, to ascertain their 

as the name order, adopted to designate them, already imp! 



where these groups are not admitted at 

the desire to determine the rela- 
relative superiority or inferiority, 

es. The first order 



m 



the first class of the animal kingdom, according to the classification of .Linnaeus, 

no doubt, his conviction that these beings, 



called 




him Primates 




1S 

among which Man is included, rank uppermost in 



their class. Blainville uses here 



of " degrees of 



and there the expression 

true Lamarck uses the same expression 



ganization," to designate orders 



It 



is 



to designate classes 



We find, therefore 



here as 



ywher 



the same 



groups adopted in our system 
these terms, and assig 
natural, and in 



to them a 



vagueness in the definition of the different kinds of 

But if we would give up any arbitrary use of 
definite scientific meaning, it seems to me most 



accordance with the practic 



of the most successful 



g 



of the animal kingdom, to call orders such divisions 



are characterized by differ 



ent 



As such I 
of Polypi, 



within the limits of the classes, 
would consider, for instance, the Actinoids and Halcyonoids in the class 



deo-rees of complication of their structure, 



as circumscribed by D 



the Hydroids, the Discoph 



and the Cte 



Mammalia 



inoderms 



Fishes, Cuvier distinguishes mostly families as well 



as orders. 



Mammalia 



soria, are divided into orders, but without families. 

8 Such are his classes of Cephalopods, Pteropods, 
numher no families, whilst others are divided into Brachiopods, and Cirripeds (Cirrhopods.) Of the Ce- 
tribes instead of families. In the class of Gasteropods, phalopods, he says, however, they constitute but one 
Annelids, Intestinal Worms, and Polyps, some of the order (Regn. An. vol. 3, p. 11), and, p. 22, he calls 
orders only are divided into families, while the larger them a family, and yet he distinguishes them as a 



number are not. 



class, p. 8. 






!i 



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i; 



m 



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■v.. 



152 



ESSAY ON CLASSIFICATION. 



Part I. 



noids among Acalephs; the Crinoids, Asterioids, Echinoids, and Holothuriae among 



Echinoderms; the Bryozoa, Brachiopods, Tunicata, Lamellibranchiata among Acephala; 
the Branchifera and Pnlmonata among Gasteropods ; the Ophidians, the Saurians, 

i a 

and the Chelonians among Beptiles ; the Ichthyoids and the Anoura among Amphi- 

bians, etc. 

Having shown in the preceding paragraph that classes rank next to branches, 
it would be proper I should show here that orders are natural groups which stand 



above families in 



their 



jpective classes ; but for obvious reasons I have deferred 

this discussion to the following paragraph, which relates to families, as it will be 

easier for me to show what is the respective relation of these two kinds of groups 

after their special character has been duly considered. 

ig orders it might be inferred that I deny 

that I assume that orders constitute neces- 



all 



From the preceding re 
gradation among all other 



narks 



groups, or 



sarily one simple series in each class. Far from asserting any such thing, I hold 
on the contrary, that neither is necessarily the case. But to explain fully my 
views upon this point, I must introduce here some other considerations. It will 
be obvious, from what has already been said, (and the further illustration of this 
subject will only go to show to what extent this is true,) that there exists an 

* 

unquestionable hierarchy between the different kinds of groups admitted in our 

systems, based upon the different 

that branches are the most comprehensive divisions, including each several classes, 

that orders are subdivisions of the classes, families subdivisions of orders, genera 

subdivisions of families, and species subdivisions of the genera; but not in the 



kinds of relationship observed among animals, 



sense that each typ 



should 



ily include the same number of classes, nor 



even 



ly several classes, as this must depend upon the manner in which 



the type is carried out. A class, again, might contain no orders, 1 if 



present- 



presented no different 



degrees characterized by the 



g 



or less compl 






cation of their structure ; or it may contain many, or few, as these gradations are 
more or less numerous and well marked; but as the representatives of any and 
every class have of necessity a definite form, each class must contain at least one 



family, or many families, indeed, as many as 



there 



are systems of forms under 



which its representatives may be combined, if form can be shown to be charac- 

genera and species; and nothing 



teristic of families. The same is the case 



with 



is more remote from the truth than the idea that a genus is better defined in 
proportion as it contains a greater number of species, or that it may be necessary 

' ■ ■ • ' 

to know several species of a genus before its existence can be fully ascertained. 
A genus may be more satisfactorily characterized, its peculiarity more fully ascer- 






1 See Chap. I. Sect. 1. 



N 



















X 



o< 









■fc. 



IV^^PMMHV^HIB^B^^-^HB^^^B^^H 





Chap. II. 



ORDERS AMONG ANIMALS 



153 
















tained, its limits better defined, when we know all its 



presentat 



■ » 

sfied that any natural g 



may be at least pointed out. however 



its species may be, from the examination of 



any single one of them 



■ 

but I am 

i 

numerous 
Moreover. 



the number of g 



both in the animal and vegetable kingdom, which contain 



but a single species, is so g 



that it is a matter of 



sity in all these cases 



species 



Ag 



such 



species 



to ascertain their generic characteristics from that one 
require to be characterized with as much precision, and their specific characters to 
be described with as much minuteness, as if a host of them, but not yet known, 

ologists and botanists, 
mus, and perhaps to 



among 



existed besides. It is a very objectionable practi 

to remain satisfied in such cases with characterizing the g 

believe, what some writers have acti 



ally stated distinctly, that in such 



g 



and specific characters are identical 



T ' 



Such being the natural relations and the subordination of types, classes, orders, 

genera, and species, I believe, nevertheless, that neither types, nor classes, 

» * 

jnera, nor species have the same 



families, 

« 

(orders of course not at all,) nor families, nor g 



standing when compared among themselves. But this does not in the least inter- 



fere with the prominent features of orders, for the relative 



standing of 



tyP 



classes, or families, or g 



■ 

or species does not depend upon the deg 



or 
of 



complicat 



- 

of their structures as that of orders does, but upon other features 



as I will now show. The four g 



typ 



T * 

or branches of the animal kingdom 



characterized as they are by four different plans of structure, will each stand higher 

an itself bears a higher or lower character, and that this may 




or lower, as the 

be the case we need only compare Vertebrata and Kadiata. 1 The different classes 
of one type will stand higher or lower, as the ways in which and the means with 
which, the plan of the type to which they belong is carried out, are of a higher 

_ 

or lower nature. Orders in any or all classes are of course higher or lower 

ves, or according to the 



■ 

according to the degree of perfection of their representatives, 

complication or simplicity of their structure. Families may stand higher or lower 

as the peculiarities of their form are determined by modifications of more or less 



important systems of org 



Genera may stand higher or lower as the structural 



peculi 



of the parts constituting the g 



characteristics exhibit 



a higher 



or lower grade of development. Sp 



lastly, may stand one above the other 



in the same g 



according to the character of their relations to the 



rrounding 



world, or that of their representatives to one another. These remarks must 



make it plai 



that the 



pective rank of groups of the same kind among them 



selves must be determined by the superior or inferior grade of those features 



upon 



I 


















I 



h\ 
























i 















i ■ 
1 1 






i 












s- 















- 

1 I must leave out the details of such comparisons, moreover, any text-book of comparative anatomy 
as a mere mention of the point suffices to suggest them ; may furnish the complete evidence to that effect 

20 



































- 




















1 



































i I 












< 









154 



ESSAY ON CLASSIFICATION. 



Part I. 



which they are themselves founded 



while orders alone are 



:tly denned by the 



natural deg 
classes. 



of structural complications exhibited within the limits of the 



As to the question, whether order 



constitute 



ly one simple series in 



their 



pectiv 



classes, I would say, that this must depend upon the character 



of the class itself, or the manner in which the plan of the type is carried out 
within the limits of the class. 



If the class is homogeneous, that is, if it is not 



primarily subdivided into sub-classes, the orders will, of course, form a 



but if some of 



there may be one or 
This 



ganic systems are developed 



single series; 
different way from the others, 



can, of course, only 



several parallel series, each subdivided into gradated orders. 

be determined by a much more minute study of the 

icsses at such 



characteristics of classes than has been made thus far, and mere g 



an internal 



gement of the classes into series, as those proposed by Kaup or 



Fitzing 
the rel 



can 




be considered as the first attempt 



ards an estimation of 



value of the intermediate divisions which may 



between 



classes 



and their orders. 

Oken and the physiophilosophers generally have taken a different view of orders. 
Their idea is, that orders represent, in their respective classes, the characteristic 

or Gelatin- 



features of the other types of the animal kingdom 



As Oken's Intestinal 



ous 



animals are characterized by a single system of orga 

distinct orders, but each class has three tribes 



the 



contain no 



th 



classes of this typ 



which are Infusoria, Polypi, and Acalephs 



intestine, they 
iponding to the 
The tribes of 






the class of Infusoria, are Infusoria proper, Polypoid Infusoria, and Acalephoid Infu 



sona : 



the tribes of the class of Polypi, are Infusorial Polypi, Polypi prop 



and 



Acalephoid Polypi; the tribes of the class Acalephs, are Infusorial Acalephs, Polypoid 
Acalephs, and Acalephs proper. 



characterized by two system 
contain each two orders, one 



But the classes of Mollusks which are said to be 
of organs, the intestine and the vascular system, 
)rresponding to the Intestinal animals, the other to 



the typ 
Acephal 



of Mollusks and so Acephala are divided into the order of Gelatinous 
and that of Molluscoid Acephala, and the Gasteropods and Cephalopods 

into two orders each. The Articulata are considered as repre- 

the intestinal, the vascular, and the respiratory 



in the same manner 



senting three systems of organs, 



ystems 



hence their classes are divided each into three orders 



For instance, the 



Worms contain an 



order of Gelatinous Worms, one of Molluscoid Worms, one of 



Verte- 



Annulate Worms and the same orders are adopted for Crustacea and Insects. 

brata are said to represent five systems, the three lower ones being the intestine, the 

vessels, and the respiratory organs, the two higher the flesh (that is, bones, muscles, 



and 



) and the 



gans of senses; hence 



five orders in each class of this 



type, as, for example, Gelatinous Fishes, Molluscoid Fishes, Entomoid Fishes, Carnal 



l 




>.J> 






/ 






Ghap. II. 



FAMILIES. 






155 




!i 












I I 
















I 









I 

Fishes, and Sensual Fishes, and so also in the classes of Eeptiles, Birds, and 



Mammalia 



i 



I have entered into so many details upon 



these vag 



of the distinguished 



German philosopher, because these views, however crude, have undoubtedly been 
suggested by a feature of the animal kingdom, which has thus far been too little 
studied : I mean the analogies which exist 



and which cross and blend, under 



exist among animals, besides their true affinities, 



modifications of strictly homological structures, 



other characters which are only analogical. But it seems to me that the subject 
of analogies is too little known, the facts bearing upon this kind of relationship 
being still too obscure, to be taken as 



the basis of such important groups in the 



animal kingdom as i 
tion or gradation of 
if under order we ai 



orders are, and I would 



upon considering the compl 



ructure as the feature which should regulate their limitation, 
to understand natural groups expressing the rank, the relative 



standing, the superiority or inferiority of animals in 
course, groups thus characterized cannot be considered 

classes, being founded upon a 



their 



ipective classes. 



Of 



mere modifications of the 




gory 



of features 































■ 












See further developments upon this subject in Naturgeschiehte, vol. 4, p. 582. Compare also the 



Oken's Naturphilosophie, 



and in his Allgemeine 



following chapter. 









SECTION 



IV. 















FAMILIES. 



Nothing 



more indefinite than the idea of 



• . V 




as 



pplied by systemat 



writers, in characterizing animals. Here 



fig 



h 



• 

g a common character, as, 



for 



means a system of the most different 

it is said of Zoophytes 



when 



that they have a 



radiated form: there, it indicates any outline which circumscribes 



the body of animals, when, for 



animal forms are alluded to in general 



instead of desig 



them simply as animals 



here 



■g 



means the special 



fig 



of some individual species 



There is in fact no group of the animal kin 




dom, however extensive or however limited, from the branches down to the species 
in which the form is not occasionally alluded to as characteristic. Speaking of Articu 



lates. C. E. v. Baer characterizes them as the type with elongated forms 



are to him the type with massive 



forms; Radiates that with periph 



Vertebrates that with double symmetry, evidently taking their form 



; Mollusks 

symmetry ; 

its widest 



sense as 



expressing the most general relations of the different dimensions of the 
























• 






■'• 










































i 




































I A 















I 



















156 



ESSAY ON CLASSIFICATION. 



Part I. 



body to one another. Cuvier speaks of form in general with reference to these 



fonr 



g 



typ 



as a 



sort of mould, as it were, in which the different type 

orders 



would seem to have been cast. Again, form is alluded to in characterizing o 

for instance, in the distinction between the Brachyourans and the Macrourans among 

It is men- 



Crustacea 



between the Saurians, the Ophidians, and the Chelonians 



tioned as a distinguishing feature in many families, ex. gr. the Cetacea, the Bats 



etc. 



Some g 



are 



parated from others in the same family on the ground 



of differences of form; and in almost every description of species, especially when 



they 



are 



considered isolatedly, the form is described at full length. Is there not, 

of the term of form, a confusion of ideas, a want of 



in this indiscriminate use 



precision in the estimation of what ought to be called form and what might be 

It seems to me to be the case. In the first place, 



? 



designated by another name 

when form is considered as characteristic of Kadiata or Articulata, or any other 



of the g 



typ 



of the animal kingdom, it is evident that it is not a definite 



outline and well-determined fig 



which is meant, but that here the word form 



used as synonym for plan 



Who, for 



would describe the tubular body of 



Holothuria as characterized by a form similar to that of the Euryale, or that of 



an Echinus as identical with that of 



Asterias 



And who does not see that, as 



far as 



the form is concerned, Holothuria) resemble Worms much more than they 
resemble any other Echinoderm, though, as far as the plan of their structure is 
concerned, they are genuine 
lates ? 



Radiates, and have nothing to do with the Art 



Ag 



a 



perficial glance at any 



and all the classes of the animal kingdom 



is 



sufficient to show that each contains animals of the most diversified forms 



What can be more different than Bats and Whales, Herons and Parrots, Fro 
Sirens, Eels and Turbots, Butterflies and Bugs, 



S 



and 



Lobsters and Barnacles, Nautilus 



and Cuttlefishes, Slugs and Conchs, Clams and compound Asidians, Pentacrinus and 



Spatangus, Beroe and Physalia, Actinia and Gorg 



And yet they belong respec 



tively to the same class, as they are coupled here : Bats and Whales together, 
etc. It must be obvious, then, that form cannot be a characteristic element of 
classes, if we would understand any thing definite under that name. 

everywhere, when applied to well- 



But form has a definite meaning 



understood 



known animals. We speak, for instance, of the human form; 
form of a horse or that of a bull conveys at once a distinct idea 



acknowledg 



the 



milarity of form of the horse and ass, and knows how 



an allusion to the 
; everybody would 

to distin- 



guish them by their form from dogs or cats, or from seals 




porpoises 



In this 



definite meaning, form 
men and women, 



iponds also to what we call figure when speak 



of 



and it is when taken in this sense, that 



I would now consider 



i ■•' 



the value of forms as characteristic of different animals. We have seen that form 









i 



\ 















- 











*■— .^H 








9 



Chap. II. 



FAMILIES. 



157 






:! 




i i 



1 . ■ 






M ' 






cannot be considered as a character of branches, nor of classes ; let us now 



examine further, whether it is a character of species 



A 



pid review of some of 



mera with 

■ 

species do 



the best known types of the animal kingdom, embracing well-defined g 

many species, will at once show that this cannot be the case, for such 

not generally show the least difference in their forms. Neither the many species 

of Squirrels, nor the true Mice, nor the Weasels, nor the Bears, 



nor the Falcons, nor 
nor the true Lizards 



the Sp 



the Fro 



o 



>r the Warblers 
nor the Toads, 



;ars, nor the Eagles, 

genuine Woodpeckers, 
the Skates, nor the Sharks 



the 



proper, nor the Turbots, nor the Soles, nor the Eels, nor the Mackerels, nor the 



Sculp 



nor the g 



Shrimps, nor the Crawfishes, nor the Hawkmoths, nor 



the Geometers, nor the Dorbugs, nor the Spring-Beetles, nor the Tapeworms 

the Cuttlefishes, nor the Slugs, nor the true Asterias, nor the Sea-Anemones 



nor 



could be distinguished among themselves, one from the other, by their form only. 
There may be differences in the proportions of some of their parts, but the pattern 
of every species belonging to well-defined natural genera is so completely identi- 
cal that it will never afford specific characters. 



There are 



g 



in our system 



which as they now stand, might be alluded to as examples contrary to this 



■ 

ment; but such g 
likely to be found 



are still based upon very questionable features, and 

to consist of unnatural associations of heterogeu 



the end 



species 
genera 



at all events, all recent improvements in Zoology have gone to limit 



gradually more 



each have shown successr 

assumed, in that respect, the most homog 



and more in such a manner, that the species belonging to 

* 

sssively less and less difference in form, until they have 



appearance 



Are natural 



g 



any 



more to be distinguished by their form 



appreciable difference in the general form 
a more or less prominent nose, larger 



one from the other? Is there any 
I say purposely general form, because 

* 

claws. 



etc., do 



form between the g 



or smaller ears, longer or shorter 

■ 

s there any real difference in the general 
of the most natural families ? Do, for instance, the 



Ily modify the form 



g< 

D 



of Ursina, the Bears, the Badger, the Wolverines, the Raccoons, differ in form 



the Phocoidaa, the D elphinoidae, the Falconinaa, the Turdinae, the Fring 



the Picinae, the Scolop 



the Chelonioidae, the Geckonina, the Colubrin 



the 



differ 



any more among 



Sparoidse, the Elateridae, the Pyralidoidse, the Echinoidae, etc., 
themselves ? Certainly not ; though to some extent, there are differences in the 
form of the representatives of one genus when compared to those of another genus ; 
but when rightly considered, these differences appear only as modifications of the 

ellipses, so do we 



* 

same typ 



of forms 



Just as there are more or less 



elongated 



find the fig 



r 

of the Badgers somewhat more contracted than that of either the 



the Baccoons, or the Wolverines, that of the Wolverines somewhat 



Bears, or 

elongated than that of the Raccoons; but the form is here 



mor 



as completely typical 


















r I 



















































I 


















II 




















"»T 


























■ 












































* 






i 






158 



ESSAY ON CLASSIFICATION 



Part I. 



as it is among the Viverrina, or among the Canina, or among the Bradypodidse, 

We must, therefore, exclude form from the 



or among the D elphinoidse, etc., etc. 
characteristics of natural 



genera, or 



at least introduce it only as a modification of 

the typical form of natural families. 

Of all the natural groups in the animal kingdom there remain then only families 

- 

and orders, for the distinction of which form can apply as an essential criterion. 



are 



least 



But these two kinds of groups are just those upon which zoologists 

agreed, so that it may not be easy to find a division which all naturalists 



would 



<g 



to take as an example of a natural order 



Let 



however, do our 



best to settle the difficulty and suppose, for a moment, that what has been said 



above 



ipect 



the 



ders is well founded, that orders are natural groups charac 

expressing the respec 



terized by the degree of complication of their structure, and 

tive rank of these groups in their class, then we shall find less difficulty in 



pointing out 



>m 



few groups which could be generally considered as orders 



I 



suppose 



most 



would agree, for instance, that among Kep tiles the Chelo- 

nians constitute a natural order ; that among Fishes, Sharks and Skates constitute 

the necessity of associating also the 

Ganoids, even 



an order also; and if any one would urge 

Cyclostomes with them, it would only the better serve my purposes 



r 

Decapods, among Crustacea, I suppose 



circumscribed within narrower limits than those I had assigned to them, and 
perhaps reduced to the extreme limits proposed for them by J. Miiller, I am 
equally prepared to take as an example, though I have in reality still some objec- 
tions to this limitation, which, however, do not interfere with my present object. 

everybody would also admit as an order, 
and I do not care here what other families are claimed besides Decapods to com- 
plete the highest order of Crustacea. Among Acephala, I trust Bryozoa, Tunicata, 
Brachiopods, and Lamellibranchiata would be also very generally considered to be 
natural orders. Among Echinoderms, I suppose Crinoids, Asterioids, Echinoids, and 
Holothurioids would be conceded also as such natural orders; among Acalephs the 
Beroids, and perhaps also Discophorae and Hydroids; while among the Polypi, the 
Halcyonoids constitute a very natural order when compared with the Actinoids. 

Let us now consider these orders with reference to the characteristic forms they 

> 

include. The forms of the genuine Testudo, of Trionyx, and of Chelonia are very 
different, one from the other, and yet few orders are so well circumscribed as that 

- 

of Chelonians. The whole class of Fishes scarcely exhibits greater differences than 



those observed in the forms of the common Sharks, the Sawfishes, the common 
Skates, and the Torpedo, not to speak of the Cyclostomes and Myxinoids, if these 
families were also considered as members of the order of Placoids. Ganoids cannot 
be circumscribed within narrower limits than those assigned to them by J. Miiller, 
and yet this order, thus limited, contains forms as heterogeneous as the Sturgeons, 



\ 





































• 



i 



• I 









\ 






Chap. II. 



FAMILIES. 



159 



the Lepidosteus, the Polypt 



Amia, and a host of extinct genera and families 



not to speak of those families I had associated with them and which Prof. Miiller 
would have removed, which, if included among Ganoids, would add still more 
heteromorphous elements to this order. Among Decapods, we need only remember 

* 

the Lobsters and Crabs to be convinced that it is not similarity of form which 

- 

holds them so closely together as a natural order. How heterogeneous Bryozoa, 
Brachiopods, and Tunicata are among themselves, as far as their form is concerned, 
everybody knows who has paid the least attention to these animals. 



Unless, then, form be too vag 



an element to characterize any kind of natural 



groups in the animal kingdom, it must constitute a prominent feature of families. 
I have already remarked, that orders and families are the groups upon which 

characterizing of which they have 
Does this not arise simply from the fact, that, on the one 



zoologists are least agreed, and to the study and 



paid least attention, 
hand, the difference betw 



ordinal and class characters has not b 



understood 



and only 
importanc 



med to be a difference of deg 



* 

and, on the other hand, that the 



of the form as the prominent character of families, has been entirely 



overlooked? For, though so 
or characterized at all, we 



few natural families of animals are well characterized, 
cannot open a modern treatise upon any class of 



animals without finding the g 



more or less 



Hy grouped together, under 



the heading of 



a g 



name with a termination in idee or ince indicating family 



and sub-family distinctions 



and most of these groups, however 



qual in absol 



value, are really natural groups, though far from designating always natural families, 

Yet they indicate 
almost without study, to point out the intermediate natural 

This arises, in my opinion, from the 



being as often orders or sub-orders, as families or sub-families. 



the facility there is 



groups between the classes and the gei 

fact, that family resemblance in the animal kingdom is most strikingly expressed 



in the general form, and that form is 



an element which falls most easily under 



our perception, even when the observation is made superficially. But, at the same 
time, form is most difficult to describe accurately, and hence the imperfection of 
most of our family characteristics, and the constant substitution for such characters 
of features which are not essential to the family. To prove the correctness of 



this 



w, 




see new 



I would or 
animals, does not the first glance 



ppeal to the experience of every naturalist 



"When 



we 



that is, the first 



ship 
is a 



? 



impression made upon 
us at once a very correct idea of their nearest relation- 
We perceive, before examining any structural character, whether a Beetle 



us by their form, g 



Carabicine, a Long 



Elaterid, a Curculionid, a Chrysomeline ; whether 



a Moth is a 



Noctuelite, a Geometrid, a Pyralid, etc.; whether a bird 



is a Dove 



Swallow, a Humming-bird, a Woodpecker, a Snipe, a Heron, etc., etc. But before 



we can ascertain its g 



we have to study the structure of some charact 



t\ 
































x 















































































\. 




























■ 


































' 
















I 







I 





















160 



ESSAY ON CLASSIFICATION 



Part I. 



parts 



before 



we can combine families into natural 



groups, we 



have to make a 



thorough investigation of their whole structure, and compare it with that of other 

■ 

families. So form is characteristic of families ; and I can add, from a careful investi- 
gation of the subject for several years past, during which I have reviewed the whole 
animal kingdom with reference to this and other topics connected with classifica- 
tion, that form is the essential characteristic of families. 1 I do not mean the mere 
outline, but form as determined by structure ; that is to say, that families cannot 
be well defined, nor circumscribed within their natural limits, without a thorough 
investigation of all those features of the internal structure which combine to deter- 

w 

mine the form. 

The characteristic of the North American Chelonians which follows, may serve 
as an example how this subject is to be treated. I will only add here, that how- 
ever easy it is at first, from the general impression made upon us by the form 
of animals, to obtain a glimpse of what may fairly be called families, few inves- 
tigations require more patient comparisons than those by which we ascertain 
the natural range of modifications of any typical form, and the structural features 
upon which it is based. Comparative anatomy has so completely discarded every 
thing that relates to Morphology; the investigations of anatomists lean so uniformly 
towards a general appreciation of the connections and homologies of the organic 






systems which go to build up the body of animals, that for the purpose of under- 
standing the value of forms and their true foundation, they hardly ever afford any 
information, unless it be here and there a consideration respecting teleological rela- 
tions. 

* 

Taking for granted, that orders are natural groups characterized by the com- 

■ 

plication of their structure, and that the different orders of a class express the 



different deg 



of that complicat 



taking now further for granted, that families 



are 



ural groups characterized by their form as determined by structural pecu 



liarities, it follows that orders are the superior kind of division, as we have seen 
that the several natural divisions which are generally considered as orders, contain 

t * 

each several natural groups, characterized by different forms, that is to say, con- 
stituting as many distinct families. 

After this discussion it is hardly necessary to add, that families cannot by any 
means be considered as modifications of the orders to which they belong, if orders 
are to be characterized by the degrees of complication of their structure, and families 















These investigations, which have led to most 



Dr. A. A. Gould, and which I would not allow to 



interesting results, have delayed thus far the publi- appear before I could revise the whole animal king- 
cation of the systematic part of the Principles of dom in this new light, in order to introduce as much 
Zoology, undertaken in common with my friend, precision as possible in its classification. 












T_^ 








I 



•: 









U 



n 



- 



Chap. II. 



GENERA. 



161 



is one question relating 



by their forms. I would also further remark, that there 
to the form of animals, which I have not touched here, and which it is still more 
important to consider in the study of plants, namely, the mode of association of 

smaller communities, as we observe them, particularly 

aggregations have not, as far as their form 



individuals into larger or 
among Polyps and Acaleph 



These 



is concerned, the same importance as the form of the individual animals of which 



they 



composed, and therefore seldom afford 



thy family characters 



this point may be more appropriately considered in connection with the 



But 
ipecial 



illustration of 



Hydroids, to which my next volume is to be devoted 



I have stated above, that botanists have denned the natural families of 




with 



g 



precision than zoolog 



those of animals; I have further remarked 



also, that most of them make no distinction between orders and families 



This 



may be the result of the peculiar character of the vegetable kingdom, which is 
not built upon such entirely different plans of structure as are animals of different 



branches 



On the 



utrary 



possible to 



among pla 



gradation 



distinctly than among animals, even 



between their higher and lower types more 

though they do not, any more than animals, constitute a simple series. It 

to me, nevertheless, that if Cryptogams, Gymnosperms, Monocotyledons, and Dico 



seems 



tyled 



can be considered as branches of the 



getable kingdom, analogous to 



Radiata, Mollusks, Articulata, and Vertebrata among animals, such divisions as Fung 



Lichens, Mosses, Hepaticse, and Ferns in the widest sense, may be taken as 

: Mosses 



AlgaB, 

classes. Diatomacese, Confervse, and Fuci may then be considered as orders 

and Hepaticse as orders; Equisetacese, Ferns proper, Hydropterids, and Lycopod 



as 



ders also; as they exhibit different deg 



of complication of 



while 



their natural subdivisions, which are more closely allied in form or habitus, may 
be considered as families; natural families among plants having generally as distinct 
a port, as families among animals have a distinct form. "We need only remember 
the Palms, the Coniferse, the Umbelliferae, the Composite, the Leguminosae, the Lab- 
iatso, etc., as satisfactory examples of this kind. 


















i 



1 ' 


























i 



■ \ 
















! f i 



































































; 










GENERA. 










SECTION 



V 









Linnaeus already knew very well that g 



exist 



calls 



g 



constitute frequently groups 



which we 



g 



in nature, though what he 

ve at present other names. 



as we consider many of them as families; but it stands proved by his writing 



21 










fc 





































































i 







■ ! 







■*v 
















162 



ESSAY ON CLASSIFICATION 



Part 1 



that he had fully satisfied himself of the real existence of such groups, for he 
says distinctly in his Phibsophia Botanica, sect. 169, * 



Scias characterem non con- 



stituere 



g 



sed 



g 



characterem 



e charactere 



Characterem 



Characterem fluere e 

i 

genus fiat, sed ut genui 



genere, non g 



» 



it 



is surprising 



that notwithstanding such clear 



statements, which might have 



kept naturalists awake respecting the natural foundation of genera, such loose ideas 



have become prevalent upon 



this 



lubject, that at present the numb 



tio-ators who exhibit much confidence in the real existence of their ow 



distinctions is very limited. And as to what g 



lly are, the 



of inves- 
i generic 

* 

want of pre- 



cision of ideas appears still g 



Those who have considered the subject at 



all seem to have come 



the conclusion that g 



are nothing but groups 



greeing in some more general features 

no difference between generic 






including a certain number of sp 

than those which distinguish species; thus recognizing 

and specific characters as such, as a single species may constitute a genus, when- 

ever its characters do not agree with the characters of other species, and many 

species may constitute a genus, 



because their specific characters agree to a certain 
extent among themselves. 1 Far from admitting such doctrines, I hope to be able 

■ 

to show that, however much or however little species may differ among themselves 
as species, yet they may constitute a natural genus, provided their respective generic 

characters are identical. 

I have stated before, that in order to ascertain upon what the different groups 
adopted in our systems are founded, I consulted the works of such writers as are 
celebrated in the annals of science for having characterized with particular felicity 

kind of these groups, and I have mentioned Latreille as prominent among 

snera of Crustacea 



any 



An 



zoologists for the precision with which he has defined the g 
and Insects, upon which he has written the most extensive work extant. 2 
anecdote which I have often heard repeated by entomologists who knew Latreille 
well, is very characteristic 



as to the meaning he 



connected with the idea of 



g 



At the time he was preparing the work just mentioned, he lost no opportunity 



of obtaining specimens 
of these animals. 



the b 



to ascertain from nature the 



g 



peculia 



and he used to apply to the entomologists for contributions to his 

• he 



collection. It was not show specimens he cared to obtain, any would do, for 
used to say he wanted them only "to examine their parts." Have we not here 
a hint, from a master, to teach us what genera are and how they should be 
characterized? Is it not the special structure of some part or other, which charac- 



1 Spring, Ueber die naturhistorischen Begriffe 
von Gattung, Art und Abart, Leipzig, 1838, 1 vol. 
8vo. 



2 Latreille, Genera Crustaceorum und Insect- 
orum, Paris et Argent. 1806-1809, 4 vols. 8vo. 







( 












V 









I ' ' ^ 













Chap. II. 



SPECIES. 



163 



terizes g 



? 



Is it not the finish of the organization 



of the body, as worked 



out in the ultimate details of structure, which distinguishes one genus from another? 
Latreille, in expressing the want he felt with reference to the study of genera, 

•note of their harmonious relations to one another. Genera 



* 

has g 



us the key 






are most closely allied groups of animals, differing neither in form, nor in com- 

plication of structure, but simply in the ultimate structural peculiarities of some 
of their parts; and this is, I believe, the best definition which can be given of 
genera. They are not characterized by modifications of the features of the fami- 

- 

lies, for we have seen that the prominent trait of family difference is to be found 
in a typical form ; and genera of the same family may not differ at all in form. Nor 

« 

are genera merely a more comprehensive mould than the species, embracing a wide 
range of characteristics ; for species in a natural genus should not present any 

- 

structural differences, but only such as express the most special relations of their 
representatives to the surrounding world and to each other. Genera, in one word, 
are natural groups of a peculiar kind, and their special distinction rests upon the 
ultimate details of their structure. 



( L 



SECTION VI. 



SPECIES 



It is generally believed that nothing is easier 



than to determine species, and 

that of all the degrees of relationship which animals exhibit, that which consti- 
tutes specific identity is the most clearly defined. An unfailing criterion of specific 
identity is even supposed to exist in the sexual connection which so naturally 
brings together the individuals of the same species in the function of reproduc- 

But I hold that this is a complete fallacy, or at least a petitio priwipii, not 
admissible in a philosophical discussion of what truly constitutes the characteristics 






tion. 



of species. I am even 



satisfied that some of the most perplexing problems involved 




in the consideration of the natural limits of species would have been solved Ion 

w 

ago, had it not been so generally urged that the ability and natural disposition 
of individuals to connect themselves in fertile sexual intercourse was of itself 
sufficient evidence of their specific identity. Without alluding to the fact that every 



new case of hybridity 



an 



g protest ag 



such an assertion, and 



■ 

Wiegman, Gekronte Preisschrift tiber die Bas- ton, (S. G.,) Essay on Hybridity, Amer. Jour., 



tarderzeugung im Pflanzenreich, Braunschweig, 1828, 



1847. 



Additional Observations 



on Hybridity in 



8vo. 



Braun, (A.,) Ueber die Erscheinung der Ver- Animals and on some collateral subjects, Charleston 



jungung in der Natur, Freiburg, 1849, 4to 



Mor- 



Med 




\i ' 
























! 






i 









. 



■ 


















j f U 












. 



i 1 ! 





















1 







































































■^** 











.- 




















































s 













164 



ESSAY ON CLASSIFICATION. 



Part I. 






without entering here into a discussion respecting the possibility or practicability 

difficulty by introducing the consideration of the limited fer- 



of setting aside this 



tility of the progeny of individuals of different species, I will only remark, 

* 

that as long as it is not proved that all the varieties of dogs, and of any others 



of our domesticated animals, and of 



cultivated plant 



are 



ipectively derived 



from one unmixed species, and as long as doubts can be entertained respectin 



the common 



g 



of all races of men from one common stock 



to admit that sexual connection resulting even in fertile offspring 
evidence of specific identity 



a 



not logical 
trustworthy 



To justify this 



I would only ask, where is the unprejudiced naturalist 



who in our days would dare to maintain: 1st, that it is proved that all the 
domesticated varieties of sheep, of goats, of bulls, of llamas, of horses, of dogs, 

: 2d, that the 



of fowls, etc., are respectively derived from one common stock 



varieties have originated from the 



complete amalgamation of 
: and 3d, that varieties 



supposition thatlthesel 

several primitively distinct species is out of the question 
imported from distant countries and not before brought together, such as the 
Shano-hae fowl, for instance, do not completely mingle? "Where is the physiologist 
who can conscientiously affirm that the limits of the fertility between distinct 
species are ascertained with sufficient accuracy to make it a test of specific identity? 
And who can say that the distinctive characters of fertile hybrids and of unmixed 
breeds are sufficiently obvious to enable anybody to point out the primitive feat- 

of all our domesticated animals, or of all our cultivated plants? As long 



ures 



■ 

as this cannot be 



done, as long as the common 



g 



of all races of men, and 



of the different animals and plants mentioned above, is not proved, while their 
fertility with one another is a fact which has been daily demonstrated for thou- 
sands of years, as long as large numbers of animals are hermaphrodites, never 



equirmg a 



connection with other individuals to multiply their species, as 



g 



as 



there are others which multiply in various ways without sexual intercourse, it is 

are unmixed species, and 
Moreover, this test can 




not justifiable to assume that those animals and 

that sexual fecundity is the criterion of specific identity 

hardly 



ever 



est. 



It 



have any practical value in most cases of the highest scientific inter- 

■ 

never resorted to, and, as far as I know, has never been applied with 
satisfactory results to settle any doubtful case. It has never assisted any anxious 
and conscientious naturalist in invest 

■ 



gating the deg 



of relationship b 



closely allied animals or 



plants 



living in distant regions or in disconnected 



g 



graphical areas. It will never contribute to the solution of any of those difficult 
cases of seeming difference or identity between extinct animals and plants found 
in different geological formations. 



In all critical 



cases, requiring 



the most minute 



accuracy and precision, it is discarded as unsafe, and of necessity questionable. 
Accurate science must do without it, and the sooner it is altogether discarded, the 






















1 



















■ 



I 



Chap. II. 



SPECIES. 



165 















better. But, like many relics of past time, it is dragged in as a sort of theo- 
retical bugbear, and exhibited only now and then to make a false show in discus- 
sions upon the question of the unity of origin 

There is another fallacy connected with the prevailing ideas about species to 
which I would also allude : the fancy that species do not exist in the same way 



of mankind 



in nature as g 



families, orders, classes, and typ 



It 



is 



tually maintained 



by some that species are founded in nature in a manner different from these groups 



that their existence is, as it were, mor 



real, whilst that of the other group 



considered as ideal, even when it is 
natural foundation. 



dmitted that these groups have themselves 




Let us consider this point more closely, as 



it involves the whole question of 



individuality 



I wish however not to be understood as undervaluing the impor 



tance of sexual relations as indicative of the close 



which unite, or may unite, 



the individuals of the same species 



I know as well as any one to what extent 



they manifest themselves in 

that these relations are not so exclusive as 



nature but I mean to insist upon the undeniable fact 

those naturalists would represent them, 



who urge them as an unfailing criterion of specific identity 



I would remind those 



who constantly forget it, that there are 



animals which, though specifically distinct 



do unite 



species, but fertile to a 



Ily, which do produce offsp 



o> 



mostly sterile 



true 



some 



limited extent in others, and 



extent which it has not yet been possible to determine 



others even fertile to an 
Sexual connection is the 



result, or rather one 



of the most striking expressions of the close relationship 



established in the beginning between individuals of the same species, and by no 



means the cause of their identity 



successive g 



When first created 



animals of the same species paired because they were made one for the other 



they did not take one another in 



order to build up their species, which had full 



existence before the first 



dividual produced by sexual connection was born 



This view of the subject acquires greater imp 



more 



pparent that species 



did not 



g 



m 



of Hybrids, as 



nee in proportion as it becomes 
ingle pairs, but were created in 
constitute the natural harmonies 
It alone explains the possibility of the procreation 
founded upon the natural relationship of individuals of closely 



large numbers, in those numeric proporti 
between organized being 



which 



differ less 



allied species, which may become fertile with one another, the more readily as they 

icturally. 

that sexual relations determine the species it should further be shown 

is the 

num- 
rarely 



To assume 
that absolute promiscuousness 



of sexes among individuals of the 



same species 



prevailing characteristic of the animal kingdom, while the fact is, that a larg 



ber even 



of animals, not to speak of Man, select their mate for life and 



any intercourse with others. It is a fact known to every farmer, that differ 





















■ 






: 












i 



I! ! 









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, 





























r~? 
























■ 















































» 









\ 












I 





1 
1 







166 



ESSAY ON CLASSIFICATION 



Part I 



ent breeds of the same species are less inclined to mingle than individuals of the 
same breed. For my own part, I cannot conceive how moral philosophers, who 



"g 



the 



ity of origin of Man as 



one of the fundamental principles of their 
religion, can at the same time justify the necessity which it involves of a sexual 
intercourse between the nearest blood relations of that assumed first and unique 



human family, when such 



revolting even to the 



,ge. Then ag 



there are innumerable species in which vast numbers of individuals are never 



developed 



lly, others in which sexual individuals app 



inly now and then 



at remote intervals, while many intermediate generations are produced without any 
sexual connection, and others still which multiply more extensively by budding 

i 

than by sexual generation. I need not again allude here to the phenomena of 
alternate generation, now so well known among Acalephs and Worms, nor to 



the polymorphism of many other typ 



Not to acknowledg 



the 



gnificance of 



such facts, would amount to the absurd pretension, that distinctions and definitions, 
introduced in our science during its infancy, are to be taken as standards for 



of framing and remodelling 



It is 



our appreciation of the phenomena in nature, instead 

our standards, according to the laws of nature, as our knowledge extends 

for instance, a specific character of the Horse and the Ass to be able to con- 

nect sexually with each other, and thus to produce an offspring different from that 

which they bring forth among themselves. 



It is characteristic of the Mare, 



as 



the representative of its species, to bring forth a Mule with the Jackass, and of 
the Stallion to procreate Hinnies with the She-ass. It is equally characteristic of 
them to produce still other kinds of half breeds with the Zebra, 
yet in face of all these facts, which render sexual reproduct 
miscuous intercourse among the representatives 



Daw. etc. 



And 



of the same 



species, so 



or at least pro- 
questionable 



a criterion of specific identity, there are still naturalists who would represent it as 
an unfailing test, only that they may sustain one single position, that all men are 



■le 



single pair 




derived from one 

These facts, with other facts which go to show more extensively every day the 
great probability of the independent origin of individuals of the same species in 
disconnected geographical areas, force us to remove from the philosophic definition 
of species the idea of a community of origin, and consequently, also, the idea of 
a necessary genealogical connection. The evidence that all animals have originated 
in large numbers is growing so strong, that the idea that every species existed in 



the beginning in single pairs, may be said to be given up almost entirely by 
naturalists. Now if this is the case, sexual derivation does not constitute a neces- 
sary specific character, even though sexual connection be the natural process of 

■ 

their reproduction and multiplication. If we are led to admit as the beginning of 



/ 



each species, the simultaneous orig 



of 



large number of individuals, if the same 
















' 









/ 







Chap. II. 



SPECIES. 



167 



species may 



originate 



at the same time in different localit 



these first repr 



sentatives of each species, at least, were not connected by sexual derivation; and as 

> * 

this applies equally to any first pair, this fancied test criterion of specific identity 
must at all events be given up, and with it goes also the pretended real exist- 

■ 

of the species, in contradistinction from the mode of existence of genera, 



ence 



families, orders, classes, and types; for what really exists 



individuals 



We may at the utmost consider individuals 



presentatives of species, but 



species. 
no one 



individual nor any number of individuals represent its species only, without repr 
sentino- also at the same time, as 



we 



have seen above 




I. to V 



g 



its 



family, its order, its class, its type. 

Before attempting to prove the whole of this proposition, I will first con- 
sider the characters of the individual animals. Their existence is scarcely limited 



as 



to time and space within definite and appreciable limits 



No 



them represent fully, 



any particular time, their species; they 



temporary 



presentatives of the species, inasmuch as each species 



one nor all of 
always only the 
exists longer in 



nature than any of its individuals. All the individuals of any or of all species 



now 



g 



are 




the successors of other individuals which have g 



before 



and the predece 
they represent 



j of the next g 
The species is ar 



aerations ; they do not constitute the species 
ideal entity, as much as the genus, the familv 






the order the class, or the type; it continues to exist, while its representatives 
die generation after generation. But these representatives do not simply repre- 
sent what is 
manner, g 



ipecific in the individual, they exhibit and reproduce in the same 









after g 



all that is g 



in them, all that charac 



terizes 



the family, the order, the class, the branch, with the same fulness, the 




same constancy, the same precision 



Sp 



manner as 
as genera, 
ent way; 



any other groups, they are quite 



families, etc., or 



quite 



as 



real 



B 



then exist in nature in the same 
as ideal in their mode of existence-/ 
it individuals truly exist in a diiFer- 



no one 



of them exhib 



time all 



characteristics of the species 



even 



though it be hermaphrodite, neither do any two represent it, even thougji 



the species be not polymorphous, for individuals have a growth, a youth, a mature 



age, an 



old 



g 



and are bound to some limited home during their lifetime 



It is true species are 



also 



mi ted in their existence ; but for our purpose, we can 



consider these limits as boundless, inasmuch as we have no means of fixin 



■ 




their 



duration, either for the past geological 



g 



or for the present period, whilst 



the short 



ycles 



of the life of individuals are easily measurable quantiti 



Now 



present their species for the time b 




do these same individuals 



present at the 



as truly' as individuals, while they e: 

and do not constitute them, so tru 

same time their genus, their family, their order, their class, and their typ 

characters of which they bear as indelibly as those of the species. 




the 



M 



^m 















' 















I 



1 ' 













































































































\ 



v 

















^ 











{ i 












































(\ 



















I 






168 



ESSAY ON CLASSIFICATION. 



Part I. 



As 



ep 




Sp 



individual animals b 



another ; they exhibit definite relations also to the 

■ 

existence is hmited within a definite period. 



the closest relations to one 
rounding elements, and their 



As rem 



9/ Genera, these same individuals have a definite and specif! 



ultimate structure, identical with that of the representat 



of other species 



As representatives of Families, these same individuals have a definite figure exhibit- 
genera, or for themselves, if the family contains 



ing, with similar forms of other 

but one genus, a distinct specific pattern. 



As representatives 




Orders, these same individuals stand in a definite rank when 



compared to the representatives of other families. 






As representatives of Classes, these same individuals exhibit the plan of structure 
of their respective type in a special manner, carried out with special means and 

in special ways. 

As representatives of Branches, these same individuals are all organized upon a dis- 



tinct plan, differing from the 




of other typ 



Individuals then are the bearers, for the time bein 




not 



nly of specific char 



acteristics, but of all the natural features in which animal life is displayed in all 

its diversity. 

Viewing individuals in this light, they resume all their dignity; they are no 
longer absorbed in the species to be for ever its representatives, without ever being 
any thing for themselves. On the contrary, it becomes plain, from this point of view, 
that the individual is the worthy bearer, for the time being, of all the riches of 
nature's wealth of life. This view further teaches us how we may investigate, not 



only the species in the individual, but the g 



also, the family, the order, the 



class, the type, as indeed naturalists have at all times proved in practice, whilst 
denying the possibility of it in theory. 

■ 

Having thus cleared the field of what does not belong therein, it now remains 
for me to show what in reality constitutes species, and how they may be dis- 



tinguished with 



precision within their natural limits. 



If we would not exclude from the characteristics of species any feature which is 
essential to it, nor force into it any one which is not so, we must first acknowledge 



that it is one of the characters of species 



to belong to a 



given period in the 



history of our globe, and to hold definite relations to the physical conditions then 
prevailing, and to animals and plants then existing. These relations are manifold, 
and are exhibited : 1st, in the geographical range natural to any species, as well 
as in its capability of being acclimated in countries where it is not primitively 
found; 2d, in the connection in which they stand to the elements around them, 
when they inhabit either the water, or the land, deep seas, brooks, rivers and 

* 

lakes, shoals, flat, sandy, muddy, or rocky coasts, limestone banks, coral reefs, swamps, 















v 
























m 
















I 






: : 


















Chap. II 



SPECIES 



169 



meadows, fields, dry lands, salt deserts, sandy deserts, moist land, forests, shady groves, 
sunny hills, low regions, plains, prairies, high table-lands, mountain peaks, or the 

• ■ * 

frozen barrens of the Arctics, etc.; 3d, in their dependence upon this or that kind 

in the mode 
of their association with one another, whether living in flocks, small companies, or 

isolated; 6th, in the period of their reproduction; 7th, in 

their metamorphosis; 



of food for their sustenance ; 4th, in the duration of their life ; 5th 



the changes they undergo 



during their growth, and the periodicity 



of these changes in 



8th, in their association with other beings, which is more or less close, as it 



may only lead to 



a 



constant association in some, whilst in others it amounts 



to parasitism; 9th, specific characteristics are further exhibited in the size animals 
attain, in the proportions of their parts to one another, in their ornamentation, 
etc., and all the variations to which they are liable. 



As 



soon as all the facts bearing upon 



" 



Assuming then, that 



these different points have been fully 
ascertained, there can remain no doubt respecting the natural limitation of species; 
and it is only the insatiable desire of describing new species from insufficient data 
which has led to the introduction in our systems of so many doubtful species, 
which add nothing to our real knowledge, and only go to swell the nomenclature 

of animals and plants already so intricate. 

species cannot always be identified at first sight, that it 
may require a long time and patient investigations to ascertain their natural limits ; 
assuming further, that the features alluded to above are among the most promi- 
nent characteristics of species, we may say, that species are based upon well 
determined relations of individuals to the world around them, to their kindred, and 

i 

upon the proportions and relations of their parts to one another, as well as upon their 
ornamentation. Well digested descript 
parative; they ought to assume the 
the 



origin 



and follow the develop 



ons of species ought, therefore, to be com- 
character of biographies, and attempt to trace 
mt of a species during its whole existence. 



Moreover, all the changes which species may undergo in course of time, especially 



under the fostering care of man, in 
to the history of the species; even 
subject, belong to their cycle, as well 



the state of domesticity and 



belong 



the anomalies and diseases to which they are 

as their natural variations. Among some 



species, variation of color is frequent, others never change, some change periodi 



My, others accidentally 



some 



throw off certain ornamental appendag 



gular 



times, the D 



the 



horns, some Birds the ornamental plumage they wear 



in 



the breeding season 



etc. 



All this should be ascertained for each, and 



no 



species 



can be considered as well defined and satisfactorily characterized, the whole history 



of which is not completed to the 



alluded 



above 



The practice prevailing 



since L 



of limiting the characteristics of species to mere diag 



has led 



to the present confusion of our nomenclature, and made it often impossible to 



22 





















i 













. 















I 









1 i- 














4/^ 












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<:. ' 












. 










































**■ 
















I 





















































! 



























































I* 



i 









170 



ESSAY ON CLASSIFICATION. 



Part I 



ascertain what were the species the authors of such condensed descript 



had 



before them 



B 



for the tradition which has transmitted, g 



after g 



ation, the knowledge of these species among the cultivators of science in Europ 
this confusion would be still greater; 



but for the preservation of most original 



collections it would be inextricable. In countries, which, like America, do not enjoy 



these advantages, 
cases of this kind 



is often hopeless to attempt critical : 
One of our ablest and most critical 



g 



g 



upon doubtful 
the lamented 



Dr. Harris, has very forcibly set forth the difficulties under which American 
naturalists labor in this respect, in the Preface to his Eeport upon the Insects 

Injurious to Vegetation. 



SECTION VII. 



OTHER NATURAL DIVISIONS AMONG ANIMALS. 



■ 



Thus far I have considered 




those kinds of divisions which are introduced 



m 



almost all our modern classifications, and attempted to show that these groups 



are founded in nature and 



ght 



be considered 



artificial devices, invented 



by man to facilitate his studies 



Up 



the closest scrutiny of the subject, I find 



that these 



divisions cover all the categories of relationship which exist among 



animals, as far as their structure is concerned. 

Branches or types are characterized by the plan of their structure, 

Classes, by the manner in which that pi 
are concerned, 

Orders, by the degrees 



executed, as far 



ways 



and means 



ees of complication of that s 
Families, by their form, as far as determined by 



Genera, by the details of the 



pecial parts, and 



Sp 



by the relations of individuals to one another and to the world in 















which they live, as well as by the proportions of their parts, their omamenta- 

tion, etc. 

And yet there are other natural divisions which must be acknowledged in a 

natural zoological system; but these are not to be traced so uniformly in all 
classes as the former, — they are in reality only limitations of the other kinds of 

■ 

divisions. 

A class in which one system of organs may present a peculiar development, 
while all the other systems coincide, may be subdivided into sub-classes ; for instance, 
the Marsupialia when contrasted with the Placental Mammalia. The characters 















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Chap. II. 



OTHER NATURAL DIVISIONS 



171 



■ 



upon which such a subdivision is founded, are of the kind upon which the class 
itself is based, but do not extend to the whole class. An order may embrace 

natural groups, of a higher value than families, founded upon ordinal characters, 



which may yet 



determine absolute superiority or inferiority, and therefore 



constitute for themselves distinct orders; as the characters upon which they are 
founded, though of the kind which determines orders, may be so blended as to 
determine superiority in one respect, while with reference to some other features 



they may indicate inferiority 



Such 



groups are called sub-orders. The order of 



Testudinata, which I shall consider more in detail in the second part of this volume, 
may best illustrate this point, as it contains two natural sub-orders. A natural 
family may exhibit such modifications of its characteristic form, that upon these 



modifications subdivisions may be distinguished, which have been called sub-families 




by some authors, tribes or legions by others. In a natural genus, a numb 



of 



species 



may agree more 



closely than others in the particulars which constitute 



the 



g 



and lead to the distinction of sub-g 



The individuals of a 



n. 



■ iHMN -. | 



sp 



occupying distinct fields of its natural geographical 



may differ somewhat from 



one 



another, and constitute varieties, etc. 




These distinctions have long ago been introduced into our 



ems, and 



every 



practical 



aturalist, who has made a special study of 



any class of the animal king 




number 



dom, must have been impressed with the propriety of acknowled 

all the various 



of subdivisions, to express all the various degrees of affinity of the different members 
of any higher natural group. Now, while I maintain that the branches, the classes, 
the orders the families, the genera, and the species are groups established in nature 



respectively upon different 



g 



and while I feel prepared to trace the natural 



limits of these groups by the characteristic features upon which they are founded 



I must confess at the same 



time that I have not yet b 



able to di 



the 



principle which obtains in 



the limitation of their 



ipective subdivisions 



All 



can say is, that all the different 



g 



considered ab 



upon which branche 



classes, orders, families, genera, and species are founded, have their degrees, and upon 



these deg 



sub-classes, sub-orders, sub-families, and sub-genera have been established 



For the present, these subdivisions must be left to arbitrary estimations, and we 
shall have to deal with them as well as we can, as long as the principles which 
regulate these degrees in the different 



hop 



kinds of groups are not ascertained 
nevertheless, that such arbitrary estimations are for ever removed from 



our 



science, 



far as the categories themselves are concerned 




Thus far, inequality of weight seems to be the standard of the internal valua- 



even 



tion of each kind of group; and this inequality extends to all groups, for 
within the branches there are classes more closely related among themselves 
than others : Polypi and Acalephs, for instance, stand nearer to one another than 



' 








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172 



ESSAY ON CLASSIFICATION 



Part I 



to Echinoderms; Crustacea and Insects are more closely allied to one another than 



to Worms, etc. 



Dp 



such deg 



their 



ipective branches, the so-called 



of relationship between the classes, within 

es have been founded, and these differ- 



have 



of distinct branches 



lly been 
Upor 



ggerated 




to g 



rise to the establishment 



similar relations between the branches, sub-kingdoms 



have also been distinguished, but I hardly think that such far-fetched combinations 
can be considered as natural groups ; they seem to me rather the expression of 



a relation arising from the 



ght of their whole org 



as compared with 



that of other groups, than the expression of a definite relationship 



SECTION VIII. 



SUCCESSIVE DEVELOPMENT OF CHARACTERS. 



It has been repeated, ag 



and 



g 



that the characters distinguishing the 



different types of the animal kingdom were developed 



in the embryo i 

first the structural features of their 



the suc- 
ispective 



cessive order of their importance : 

branches, next the characters of the class, next those of the order, next those 

I This 



of the family, next those of the g 



and finally those of the species 



has met with 



direct opposition 



the contrary 



have been 



approved almost without discussion, and to be generally taken for granted now. 
The importance of the subject requires, however, a closer scrutiny; for if Embry- 
ology is to lead to great improvements in Zoology, it is necessary, at the outset, 
to determine well what kind of information we may expect it to furnish to its 
sister science. Now I would ask if, at this day, zoologists know with sufficient 



precision what are typical 



ordinal, family, g 



and specific characters, to 



be justified in maintaining that, in the progress of embryonic growth, the features 



which become 



order of their subordination 



ely prominent 



ipond to these characters and in the 



I doubt it. 



I 



ill 



say more 



I am sure there is 



no such understanding about it among them, for if there was, they would already 
have perceived that this assumed coincidence, between the subordination of natural 
groups among full-grown animals and the successive stages of growth during their 

embryonic 

features in the embry 



period of life, does not exist in nature. It is true, there are certain 



development which may 



gg 



the idea of a prog 



from a more general typical organization to its ultimate specialization, but it nowhere 



proceeds 



that 



typed order of succession, nor indeed even in a general way 



in the manner thus assumed. 






. * 






i 



















i 
I 






i 



.1 , 



■ 













Chap. II. 



SUCCESSION OF CHARACTERS. 



173 



Let us see whether it is not possible to introduce more precision in this matter. 

I have said about the characteristics of the natural 

correct, that we have, 1st, four great typical 

ans of structure ; 



Takino- for granted that what 



the animal kingdom is 



groups m 

branches of the animal kingdom, characterized by different 




2d, classes, characterized by the ways in which and the means with which these 
plans of structure are executed ; 3d, orders, characterized by the degrees of simplicity 
or complication of that structure ; 4 th, families, characterized by differences of form, 
or by the structural 
ultimate peculiarities 



peculiarities determining form 



5th 



g 



snera, characterized by 
of structure in the parts of the body ; 6th, species, charac- 
terized by relations and proportions of parts among themselves, and of the indi- 
viduals to one another and to the surrounding mediums; we reach, finally, the 

* 

individuals which, for the time being, represent not only the species with all 



their varieties, and variati 
of all the higher groups 



of age, sex, s 
"We have thus 



but also the characteristic features 
end of the series, the most com- 



prehensive categ 
individual beings 



3 of the structure of animals, while at the other end we meet 
Individuality on one side, the most extensive divisions of the 



animal kingdom on the other 



Now, to begin our critical examination 



of the 



prog 



of life in 



its successive manifestations with the extremes, is it not 




from all we 



know of Embryology, that individualization is the first requirement 



of all reproduction and multiplication, and that an individual germ 



a number 



of them,) an ovarian 



m 



or a bud, is first formed and becomes distinct as an 



individual from the body of the parent, before it assumes either the characters 



of 



great typ 



those of its class, order, etc.? This fact is of great significance 



as 



showing the importance of individuality 



Next, it is true, we perceive 



generally the outlines of the pla 
what manner that plan is 



of structure, before it becomes apparent in 



to be carried out; the character of the 




marked 




its most general features, before that of the class can be recognized with 



out, in 

any degree of precision 

generalizations in 

It has been 



Up 



this fact, we may base one of the most important 



gy 



pass 
classes. 

there 



Embryolo 
maintained, in the most general terms, that the higher animals 

during their development through all the phases characteristic of the inferior 



are 



Put in this form, no statement can be further from the truth, and yet 
decided relations within certain limits, between the embryonic stages of 



growth of higher animals and the permanent characters of others of an inferior 

Now the fact mentioned above, enables us to mark with precision the limits 



b 



traced 



grade. I 

within which these relations may 

tion, animals do not differ one from the other 

begun 



As 



g 



in their primitive condi 



but as soon as the 



mbry 



has 



to show any characteristic features, it presents such peculiarities as dis 



guish its typ 



It cannot, therefore, be said that any animal 



passes through 



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174 



ESSAY ON CLASSIFICATION. 



Part I. 



ph 



of development, which are not included within the limits of its own typ 



no Vertebrate is, or resembles, at any time an Articulate, no Articulate a Mollusk, 
no Mollusk a Radiate, and vice versa. Whatever correlations between the young of 
higher animals and the perfect condition of inferior ones may be traced, they are 
always limited to representatives of the same great types; for instance, Mammalia 
and Birds, in their earlier development, exhibit certain features of the lower classes 
of Vertebrates, such as the Reptiles or Fishes; Insects recall the Worms in some 
of their earlier stages of growth, etc., but even this requires qualifications to 

■ 

which we shall have to refer hereafter. However, thus much is already evident, 
that no higher animal passes through phases of development recalling all the lower 



types 
has b 



of the animal kingdom, but only such as belong to its own branch 



What 



said of the infusorial character of young embryos of Worms, Mollusks 



and Radiates, can no 



g 



stand before a serious criticism, because 



- 

the first 




the animals generally called Infusoria cannot themselves be considered as a 



natural class; and in the second 




those to which a reference is made in this 



connection, are themselves free-moving embryos. 1 



With the 



prog 



* 

of growth and in proportion as the type of an animal 



becomes more distinctly marked, 



mbry 



the plan of structure appears 



also more distinctly in the peculiarities of that structure, that is to say, in the 

■ 

ways in which and the means by which the plan, only faintly indicated at first, 
is to be carried out and become prominent, and by this the class character is 
pointed out. For instance, a wormlike insect larva will already show, by its tracheas, 
that it is to be an Insect and not to remain a Worm, as it at first appears to 
be; but the complications of that special structure, upon which the orders of 



the class of Insects are based, do not yet appear 



this 



is 



perfected 



nly at a late 



period in the embryonic life. At this stage, we frequently notice already a remark- 
able advance of the features characteristic of the families over those characteristic of 
the order; for instance, young Hemiptera, young Orthoptera may safely be referred 
to their respective families, from the characteristics they exhibit before they show 
those peculiarities which characterize them as Hemiptera or as Orthoptera ; young 
Fishes may be known as members of their respective families before the charac- 

■ 

ters of their orders are apparent, etc. 

It is. very obvious why this should be so. With the progress of the develop- 

ment of the structure, the general form is gradually sketched out, and it has 
already reached many of its most distinctive features, before all the complications 
of the structure which characterize the orders have become apparent; and as form 
characterizes essentially the families, we see here the reason why the family type 






» 












See above, Chap. I., Sect. 18, p. 75 












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r^^^^^^^^^^K^^M^W^M 







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Chap. II. 



SUCCESSION OF CHARACTERS. 



175 



may be fully stamped upon an animal before its ordinal characters are developed. 
Even specific characters, as far as they depend upon the proportions of parts and 
have on that ground an influence in modifying the form, may be recognized long 



before the ordinal characters are fully developed. The Snapping-Turtle, for 



exhibits its small crosslike sternum, its Ion 



tail, 



ferocious hab 



befo 



it 



leaves the egg, before it breathes through lungs, before its derm is ossified to form 



a 



bony shield, etc.; nay, it snaps with its gapin 



J 



at any thing brought 



near though it be still surrounded by its amnios and allantois, and its yolk still 

exceeds in bulk its whole body. 1 The calf assumes the form of the bull before 
it bears the characteristics of the hollow-horned Ruminants; the fawn exhibits all 






the peculia 



of its species before those of its family are unfolded 



With reference to gene: 
ever developed in any typ 



characters, it may be said that they are 



ely 



are 



> of the animal kingdom, before the specific features 

* 

for the most part fully sketched out, if not completely developed. Can there 
be any doubt that the human embryo belongs to the genus Homo, even before it 
has cut a tooth? Is not a kitten, or a puppy distinguishable as a cat or a dog, 



befor 



the claws and teeth tell their g 



? 






the Colt, the Rabbits, and the Mice, of most Birds, most Reptiles, most 



the Kid, 

Fishes, most Insects, Mollusks and Radiates 



And 



hy should this be 



because the proporti 



of parts, which constitute specific characters, are 



Simply 
recog- 



nizable before their ultimate 
completed. 



ctural development, which character 



g 



is 



It seems to me 



■ 

that these facts are likely to influence the future 



prog 



of Zoology, in enabling us gradually 



to unravel more and more distinctly, the 



features which characterize the different subordinate groups of 



the animal kino; 



dom 



The views I have expressed above of the respective value and the promi- 
nent characteristics of these different groups, have stood so completely the test in 



this 



aly 



of their successive appearance, that I consider this circumstance 



as 



adding to the probability of their correctness. 



m 



But this has another very important bearing, to which I have already alluded 
the beginning of these remarks. Before Embryology can furnish the means of 



g 



some of the most perplexing problem 



Zoology, it is indispensable to 



ascertain first what are typical, classic, ordinal, family, generic, and specific charac 



ters; 



and as long as it could 



be 



pposed that these characters appear 



,rily 






Is this not true also of the Lamb. J 




L 



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1 Pr. M. v. Neu-Wjed quotes as a remarkable it was still a pale, almost colorless embryo, wrapped 

fact, that the Chelonara serpentina bites as soon as it up in its foetal envelopes, with a yolk larger than 

is hatched. I have seen it snapping in the same itself hanging from its sternum, three months before 

fierce manner as it does when full-grown, at a time hatching. 



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176 



SSAY ON C 



Part I. 



during the embryonic 



growth, in the order of their subordination, there was no 
possibility of deriving from embryological monographs, that information upon this 
point, 

Again, 



so much needed in Zoology, and so seldom alluded to by embryologists. 
without knowing what constitutes truly the characters of the groups named 
above, there is no possibility of finding out the true characters of a genus of 

which only one species is known, of a family which contains only one genus, etc., 

L 

and for the same reason no possibility of arrivii 



g 



at congruent 



results with refer 



ence to the natural limitations of genera, families, orders, etc., without which we 
cannot even begin to build up a permanent classification of the animal kingdom; 
and still less, hope to establish a solid basis for a general comparison between 
the animals now living and those which have peopled the surface of our globe 
in past geological ages. 

It is not accidentally I have been led to these investigations, but by necessity. 
As often as I tried to compare higher or more limited groups of animals of the 
present period with those of former ages, or early stages of growth of higher living 



animals with full-grown ones of lower typ 



I 



was 



itantly 



- 

pped in my 



by doubts as to the equality of the standards I was applying, until I 



progress 

made the standards themselves the obj 



of direct and very extensive 



investiga- 

tions, covering indeed a much wider ground than would appear from these remarks 



for, upon these principles, I have already remodelled, for my own conven 
the whole animal kingdom, and introduced in almost every class very 



. ' 



nearly 
pected 



changes in the classification. 

I have already expressed above l my conviction that the only true system is 

■ 

that which exists in nature, and as, therefore, no one should have the ambition 
of erecting a system of his own, I will not even attempt now to present these 
results in the shape of a diagram, but remain satisfied to express my belief, that 
all we can really do is, at best, to offer imperfect translations in human language 
of the profound thoughts, the innumerable relations, the unfathomable meaning of 



themselve 



and I should con- 



the plan actually manifested in the natural objects 

sider it as my highest reward should I find, after a number of years, that I had 

helped others on in the right path. 



. 



1 See Chap. L, Sect. 1, p. 7-9. 






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Chap. II. 



CONCLUSIONS 



177 



SECTION IX. 



CONCLUSIONS. 






The importane 



of such an 



g 



as the preceding. 




be obvious to 



every philosophical investigator, 
groups introduced into a 



As 



as it is understood that all the different 



natural 



system may have a definite meaning 



as 



it can be shown that each exhibits a definite relation among 



as soon 
g beings, 



founded in nature, and no more subject to arbitrary modifications than any other 
law expressing natural phenomena ; 



as soon as it is made 




that the natural 



limits of all these groups may be ascertained by careful 



stigations, the 



m 



the 



dy of classification or the systematic relationship 



g among all 



ganized beings, which has almost ceased to engage the attention of the more 



careful original 



will be revived, and the manifold ties which link 



g 



pt 



together all animals and plants, as the living expression of a 

carried out in the course of time, like a soul-breathing epos, will be scrutinized 

anew, determined with greater precision, and expressed with increasing clearness 



and propriety 



Fanciful and artificial classifications will gradually lose their hold 



upon a 



b 



informed community 



scientific men themselves will be restrained 



from bringing forward immature and prematur 
new species will have a claim upon 



g 



no characterist 



of 



the 



of the learned, which has not been 



fully investigated and compared with those most closely allied to it; no genus 
will be admitted, the structural peculiarities of which are not clearly and distinctly 
illustrated; no family will be considered as well founded, which shall not exhibit 
distinct system of forms intimately combined and determined by structural rela- 



a 






tions ; 
degre< 



10 order will appear admissible, which shall not represent a well-marked 
of structural complication; no class will deserve that name, which shall 



\ 



not appear as a 



distinct and independent expression of some general 




of 



ture, carried out in a peculiar way and with peculiar means 



no 



tjP 



will be 



gnized as one of the fundamental groups of the animal kingdom, which shall 



not exhibit a 




of its own 



not convertible into another 



be justified in introducing any 



of these groups 



5 



1st, that it is a natural group 



2d. that 



No naturalist will 
nto our systems without show- 
a group of this or that kind. 



may 



be orders 



to avoid, henceforth, calling families groups that may be genera, families groups that 

classes or types groups that may be orders or classes; 3d, that the 

characters by which these groups may be recognized are in fact respectively specific, 

23 















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' I 









178 



ESSAY ON CLASSIFICATION 



Part I 



generic, family, ordinal, classic, or typical characters, so that our works shall no 



longer exhibit the 



annoying confusion, which is to be met almost 



ywhere, of 



generic characters in the diagnoses of 

in the characteristics of classes and types. 1 



species, or 



of family and ordinal characters 



more 



It may perhaps be said, that all this will not render the study of Zoology 

I do not expect that it will; but if an attentive consideration of what 



easy 



I have stated in the preceding pages respecting classification, should lead to a 
more accurate investigation of all the different relations existing among animals, 
and between them and the world in which they live, I shall consider myself 

■ 

having fully succeeded in the object I have had in view from the beginning, 



as 



m 



this 



inquiry 



Moreover, it is high time that certain zoologists, who would call 



themselves investigators, should remember, that natural objects, to be fully under- 



stood, require more than a passing g 



they should imitate the example of 



astronomers, who have not become tired of looking into the relations of the few 
members of our solar system to determine, with increased precision, their motions, 
their size, their physical constitution, and keep in mind that every organized 
being, however simple in its structure, presents to our appreciation far more com- 
plicated phenomena, within our reach, than all the celestial bodies put together; 
they should remember, that as the great literary productions of past ages attract 

■ 

ever anew the attention of scholars, who can never feel that they have exhausted 

of God, which it is 



so the living works 



the inquiry into their depth and beauty, 

the proper sphere of Zoology to study, would never c* 

to them, should they proceed to the investigation with the right spirit. 



present 



Their 



studies ought, indeed, inspire every one with due reverence and admiration for such 
wonderful productions. 

The subject of classification in particular, which seems to embrace apparently 
so limited a field in the science of animals, cannot be rightly and fully under- 
stood without a comprehensive knowledge of all the topics alluded to in the 
preceding pages. 



1 As I do not wish to be personal, I will refrain any characterization of genera, of families, of orders, 



from quoting examples to justify this assertion, I 
would only request those who care to be accurate, to 



of classes, and of types, to satisfy themselves that 
characters of the same kind are introduced almost 



examine critically almost any description of species, indiscriminately to distinguish all these groups. 








































^m ^M^WVv 










iJ 






■ 



CHAPTER THIRD. 



NOTICE OF THE PRINCIPAL SYSTEMS OF ZOOLOGY 



SECTION I 



GENERAL REMARKS UPON MODERN SYSTEMS. 



Without attempting to give an historical account of the leading features of all 



a 



zoological systems, it is proper that I should here compare critically the practice 
of modern naturalists with the principles discussed above. With this view, it 
would hardly be necessary to go back beyond the publication of the « Animal 
Kingdom," by Cuvier, were it not that Cuvier is still represented, by many naturalists, 



d especially by Ehrenberg 



and some other German 



g 



division of the whole animal kingdom 



two 



great 



group 



one 



as favoring the 
containing the 



Vertebrates, and the other all the remaining classes, under the name of Inve 



brates, while in reality 



was he, who first, dismissing his own earlier views 



introduced into the classification of the animal kingdom that fourfold division which 

• ■ 

has been the basis of all improvements in modern Zoology. He first showed that 
animals differ, not only by modifications of one and the same organic structure, 
but are constructed upon four different plans of structure, forming natural, distinct 

* 

groups, which he called Kadiata, Articulata, Mollusca, and Vertebrata. 

It is true, that the further subdivisions of these leading groups have under- 
gone many changes since the publication of the "Regne Animal." Many smaller 
groups, even entire classes, have been removed from one of his "embranchments" 
to another; but it is equally true, that the characteristic idea which lies at the 
bottom of these great divisions was first recognized by him, the greatest zoologist 



of all times. 



Ehrenberg, (C. G.,) 



Meeres 



:, 4to., p. 30 












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180 



ESSAY ON CLASSIFICATION. 



Part I. 



The question which I would examine here in particular, is not whether the 



circumscript 



/ 



of these 



g 



roups was accurately defined by C 



whether 



the 



minor groups referred to them 




belong there or elsewhere, nor how far 



these divisions may be improved within their respective limits, but whether there 



are four great fundamental groups in the 



animal kingdom, 



based upon four differ- 



ent plans of structure, and neither more nor less than four. This question is 
very seasonable, since modern zoologists, and especially Siebold, Leuckart, and Vogt 

have proposed combinations of the classes of the animal kingdom into higher groups, 
differing essentially from those of Cuvier. It is but justice to Leuckart to say 
that he has exhibited, in the discussion of this subject, an acquaintance with the 
whole range of Invertebrata, 1 which demands a careful consideration of the changes 
he proposes, as they are based upon a critical discrimination of differences of great 
value, though I think he overrates their importance. The modifications intro- 
duced by Vogt, on the contrary, appear to me to be based upon entirely unphysio- 
logical principles, though seemingly borrowed from that all important guide, Em- 
bryology. 

The divisions adopted by Leuckart are: Protozoa, (though he does not enter 
upon an elaborate consideration of that group,) Coelenterata, Echinodermata, Vermes, 
Arthropoda, Mollusca, and Vertebrata. 



The classification adopted, many years before 










by Siebold, in his text-book of comparative anatomy, is nearly the same 



pt 



that Mollusks follow the Worms, that Coelenterata and Echinoderms are united 
into one group, and that the Bryozoa are left among the Polyps. 

Here we have a real improvement upon the classification of Cuvier, inasmuch 

among the Radiates, and brought nearer the 



as 



the Worms are removed 




Arthropods, an improvement however, which, so far as it is correct, has already 

anticipated by many naturalists, since Blainville and other zoologists long 



been 



ago felt the impropriety of 



allowing them to remain among Radiates, and have 



been induced to associate them more or less closely with Articulates. But I 
believe the union of Bryozoa and Rotifera with the Worms, proposed by Leuckart, 
to be a great mistake ; as to the separation of Coelenterata from Echinoderms, I 

sration of the difference which exists between Polyps and 



consider it as an 



&g 



Acalephs on the one hand, and Echinoderms on the other. 



/ 



The fundamental groups adopted by Vogt, 2 are : Protozoa, Radiata, Vermes, Mol- 
lusca, Cephalopoda, Articulata, and Vertebrata, an arrangement which is based solely 
upon the relations of the embryo to the yolk, or the absence of eggs. But, as 



Morpholep 



Vogt, (Carl,) Zoologische Briefe* Naturge 



Verwandt shafts verhaltnisse der wirbellosen Thiere, schichte der lebenden und untergegangenen Thiere 



Braunschweig, 1848, 1 vol., 8vo. 



Frankfurt a- M., 1851 ; vol- 1, p. 70. 

























I 






i 






Chap. III. 



MODERN SYSTEMS. 



181 



I 






I have already stated, this is an entirely unphysiological principle, inasmuch as it 
assumes a contrast between the yolk and the embryo, within limits which do not 

* 

exist in nature. The Mammalia, for instance, which are placed, like all other Verte- 
brata, in the category of the animals in which there is an opposition between the 
embryo and the yolk, are as much formed of the whole yolk as the Echinoderms 
or Mollusks. The yolk undergoes a complete segmentation in Mammalia, as well as 
in Radiates or Worms, and most Mollusks; and the embryo when it makes its 
appearance no more stands out from the yolk, than the little Starfish stands 

out from its yolk. These simple facts, known since Sars and Bischoff published 

* 

their first observations, twenty years ago, is in itself sufficient to show that the 



any 



eg 



■g 



whole principle of classification of Vogt is radically wrong. 

Respecting the assertion, that neither Infusoria nor Rhkopoda produ 

I shall have more to say presently 

Vertebrata, Articulata, Cephalopoda, Mollusca, Vermes, Radiata, and Protozoa 

Voo-t's system, it must be apparent to every zoologist conversant with the natural 



■ 



As to the arrangement of the leading groups, 

in 



affinities of animals, that a classification which interposes the whole 



of Mollusks 



between the typ 



of Articulata and Worms, cannot be correct. A classificat: 



based, like this, solely upon the chang 



which the yolk undergo 



is not likely 



to be the natural expression of the manifold relations existing between all animals. 
Indeed, no system can be true to nature, which is based upon the consideration 

of a sii 



single part, or a single orgam 
After these general remarks, I have 




that there are 
more nor less. 




four g 



to show more in detail, why I believe 
fundamental groups in the animal kingdom, neither 



With reference to Protozoa, first 



must be 



acknowledged 



that, notwithstanding 



the extensive 



g 



of modern writers upon Infusoria and Rhizopoda, the 



true nature of these beings is 
wandering from one end of the 



still very little known. The Rhizopoda have b 



of Invertebrata 



the 



without finding; 



a 

to 



pla 



generally acknowledged as expressing their true affinities 



The 



attempt 



parate them from all the 



with which they have been so long associated 




them with the Infusoria in one distinct branch, appears to 



and to 

mistaken as any of the former 



me as 



gements, for I do 



consider that their 



animal nature is yet proved beyond a doubt, though I have myself once 



g 



gested the possibility of a 



definite relation between them and the lowest Gaste 



pods 



Since it has been satisfactorily ascertained that the Corall 



Al 






which contain more or 



less lime in their structure, and 



genuine 



there is hardly 



any group among 



the lower animals and lower plants, which does not contain 

■ 

simple locomotive individuals, as well as compound communities, either free or adher- 
ing to the soil, I do not see that the facts known at present preclude the possibility 






H 


























. . 


















i I 



■ i 



\ 

























I 









• ' 


















F 













































































































I 



























I 



I 



1 
J 









182 



ESSAY ON CLASSIFICATION. 



Part I 



. * 



of an association of the Rhizopods with the Algae. 1 This would almost seem natural, 

we consider that the vesicles of many Fuci contain a viscid, filamentous 



when 

substance, so similar to that protruded from the body of the Rhizopods, that the 
most careful microscopic examination does not disclose the slightest difference in its 
structure from that which mainly forms the body of Rhizopods. The discovery 
by Schultze 2 of what he considers as the germinal granules of these beings, by no 

■ 

means settles this question, though we have similar ovoid masses in Algae, and 



though 



* 

g the latter, locomotive forms are also very numerous. 






With reference to the 



Infusoria, I have long since 



expressed my conviction that 

they are an unnatural combination of the most heterogeneous beings. A large 
number of them, the Desmidieae and Volvocinae, are locomotive AlgaB. Indeed, 
recent investigations seem to have established beyond all question, the fact, that 
all the Infusoria Anentera of Ehrenberg are Algas. The Enterodela, however, are 
true animals, but belong to two very distinct types, for the Vorticellidse differ 
entirely from all others. Indeed, they are, in my opinion, the only independent 
animals of that group, and so far from having any natural affinity with the other 
Enterodela, I do not doubt that their true place is by the side of Bryozoa, 
among Mollusks, as I shall attempt to show presently. Isolated observations which 

■ 

I have been able to make upon Paramecium, Opalina, and the like, seem to me 

■ 

■ 

sufficient to justify the assumption that they disclose the true nature of the 
bulk of this group. I 
Paramecium were born, which underwent all the changes these animals are known to 
undergo up to the time of their contraction into a chrysalis state ; while the Opalina 



have seen, for instance, a Planaria lay eggs out of which 



is hatched from Distoma 



m 



i 



hall publish the details of these observations 



on another occasion. 



B 



;■ 



if it can be shown that two such types as Paramecium 



and Opalina are the progeny of Worms, it seems to me to follow, that all the 



Enterodela, with the 



pt 



of the Vorticellidse, must be considered as the 



r 

embryonic condition of that host of Worms, both parasitic and free, the meta- 



4 

morphosis of which is still unstudied 



In this 



I might further remark 



that the time is not long past when Cercaria was also considered as belonging 
to the class of Infusoria, though at present no one doubts that it belongs to 
the cycle of Distoma; and the only link in the metamorphosis of that genus which 

■ 

was not known is now supplied, since, as I have stated above, the embryo which 
is hatched from the egg laid by the perfect Distoma is found to be Opalina. 

All this leads to the conclusion, that a division of the animal kingdom to be 
called Protozoa, differing from all other animals in producing no eggs, does not 
exist in nature, and that the beings which have been referred to it have now 






• ~ 






1 



Comp. Chap. L, Sect. 18, p. 75 



2 Schultze, (M. S.,) Polythalamien, q. a. ; p. 24 
















■■■■i 





Kaa- . i- 1 . 
















1 






Chap. III. 



MODERN SYSTEMS. 



183 






to be divided, and 



ed 



partly among plants, in the class of Algse, and partly 
among animals, in the classes of Acephala, (Vorticellae,) of Worms, (Paramecium and 



Opalina,) and of Crustacea (Rotifera) ; Vorticellse b 
fore Acephalous 



g 



Mollusks, while the beautiful 



g 



of D 



h 



proved the Rotifera to be g 



Crustacea, and not Wo 



Bryozoa and there- 
ana and Leyd 






rms 



The g 



type of Radiata 



g its leading features only, was first recognized 



by C 



belong to it. 



at the time, but partly 



though he associated with it many animals which do not properly 

This arose partly from the imperfect knowledge of those animals 

in this instance, 



from the fact that he allowed himself. 



to deviate from his own principle of classification, according to which types are 



founded upon special 




of structure. With reference to Radiata, he departed 




indeed, from this view, so far as to admit, besides the consideration of their peculiar 
an, the element of simplicity of their structure as an essential feature in the 
typical character of these animals, in consequence of which he introduced five classes 
among: Radiata: the Echinoderms, Intestinal Worms, Acalephs, Polypi, and Infusoria. 
In opposition to this unnatural association, I need not repeat here, what I have 
already stated of the Infusoria, when considering the case of Protozoa ; neither is it 



necessary 
and conn 



g 



•ge again the propriety of removing the Worms from among Radiata, 
them with Articulata. There would thus remain only three classes 



among Radiates, — Polypi, Acalephs, and Echinoderms, — which, in my opinion, con- 
stitute really three natural classes in this great division, inasmuch as they exhibit 



the three different ways in 



which the characteristic plan of the type, radiation 






is carried out, in distinct structures. 



S 



it can be shown that Echinoderms are, in a general way, homolog 



in their structure with Acalephs and Polyp 
belong to one and the same great type, 



must be admitted that these classes 



and that they are the 



nly 



presenta 



of the branch of Radiata, assuming of course that Bry 



Corallinae, Sponges 



and all other foreig 



admixtures have been removed from among Polyp 



it is this Cuvierian type 
which Leuckart undertakes 



of Radiata, thus freed of all its heterog 



3. Now 

elements 



divide 



two branches, each of which he considers 



qual with Worms, Articulates, Mollusks, and Vertebrates 



He 



was 



undoubtedly 



led to this 



gg 



of the difference 



g between Echinoderms 



side and Acalephs and Polypi on the other, by the apparently greater rei 
of Medusae and Polypi, 1 and perhaps still more by the fact, that so many 
Acalephs, such as the Hydroids, including Tubularia, Sertularia, Campanularia, etc., 



on one 

emblance 

genuine 



are still comprised by most 



g 



in the class of Polyp 



. 














i 


















4 



^m 
































































i 









We 



mi 



of 



overridden the primary feature of branches, their 
plan, to exalt a class to the rank of a branch. 


































ill 






■■■■■■■■■■ 














c 






















' 



, 









































ii 






■'.. 






184 



ESSAY ON CLASSIFICATION. 



Part I. 



But 



since the admirable investigations of J. Miiller have made ns familiar with 
the extraordinary metamorphosis of Echinoderms. and since the Ctenophorae and 
the Siphonophorae have also been more carefully studied by Grube, Leuckart, 
Kolliker, Vogt, Gegenbaur, and myself, the distance which seemed to separate Echino- 
derms from Acalephs disappears entirely, for it is no exaggeration to say, that 









• 

were the Pluteus-like forms of Echinoderms not known to be an 



arly 



£ 



in 



the transformation of Echinoderms, they would find as natural a place among 
Ctenophorae, as the larvae of Insects among Worms. I therefore maintain, that 
Polypi, Acalephs, and Echinoderms constitute one indivisible primary group of the 
animal kingdom. The Polypoid character of young Medusae proves this as plainly 
as the Medusoid character of young 



Further, nothing can 



be 



sung Echinoderms. 
more unnatural than the transfer of Ctenopho 



to 



exhibit the closest 



the type of Mollusks which Vogt has proposed, for Ctenoph 

homology with the other Medusae, as I have shown in my paper on the Beroid 

Medusae of Massachusetts. The Ctenophoroid character of 

« L 

■ 

establishes a second connection between Ctenophorae 



young 



Echinoderms 



and the other Badiata, of as 



great importance as the first. We have thus an anatomical link to connect the 



Ctenoph 



with the 



g 



Medusae, and an embryological link to connect them 



with the Echinoderms 



The classification of Badiata may, therefore, stand thus: 



L 

1st Class: Polypi; including two orders, the 



Aetinoids 




I the I Haley c- 

noids, as limited by Dana. 

2d Class: Acalephae; with the following orders: Hydroids, (including Sipho- 

* t 

nophorse,) Discophorse, and Ctenophorae. 

3d Class: Echinoderms; with Crinoids, Asteroids, Echinoids^ and Holothu- 
rioids, as orders. 

The natural limits of the branch of Mollusks are easily determined. Since the 
Cirripeds have been removed to the branch of Articulata, naturalists have generally 
agreed to consider, with Cuvier, the Cephalopods, Pteropods, Gasteropods, and 
Acephala as forming the bulk of this type, and the discrepancies between modern 
investigators have mainly resulted from the views they have taken respecting the 
Bryozoa, which some consider still as Polyps, while others would unite them with 

* 

the Worms, though their affinity with the Mollusks seems to me to have been 



F 

clearly demonstrated by the 



tigat 



of Milne-Edwards 



Vogt is the 



nly 



built 



upon a 




naturalist who considers the Cephalopoda "as 

though he does not show in what this peculiarity of plan 

the well-known anatomical differences which distinguish them from the other classes 



entirely peculiar; 1 
but only mentions 



1 Vogt, (C.,) Zoologische Briefe, q. a. ; vol. 1, p. 361 






■ 




x^^- 1 



*w 



:.. 






^■^^^■■^^■■^■■^B 











/ 



Chap. III. 



MODERN SYSTEMS. 



185 



of the branch of Mollusks. These differences, however, constitute only class char 
ters and exhibit in no way a different 




to homologize all the systems of 



g 



an. It is, indeed, by no means difficult 
of the Cephalopods with those of the 
other Mollusks, and with this evidence, the proof is also furnished that the Cepha- 
lopods constitute only a class among the Mollusks. 

As to the differences in the development of the Cephalopods and the other 
Mollusks, the type of Vertebrata teaches us that partial and total segmentation 



of the yolk are not inconsistent with 




of type, as the eggs of Mammalia and 



Cyclostomata underg 



a 



total 



gmentation, while the process of segmentation is 



more or less limited in the other classes. In Birds, Kept 



and Selach 



the 



i 



gmentation is only superficial 



Batrachians, and most Fishes, it is much deep 



and yet no one would venture to separate the Vertebrata into several distinct 
branches on that account. With reference to Bryozoa, 



the 



can be no doubt 



that their association with Polypi or with Worms is contrary to their natural 
affinities. The plan of their structure is in no way radiate ; it is, on the con- 



trary, distinctly and 



illy bilateral 



and as soon as their close affinities with 



the Brachiopods, alluded to above, 1 are fully understood, no doubt will remain of 
their true relation to Mollusks. As it is not within the limits of my 




to 



illustrate here the characters of all the classes of the animal kingdom, I will only 
state further, that the branch of Mollusks appears to me to contain only three 



classes, as follows: 

1st Class: Acephal 
chiopods, Tunicata, and Lamellibranchiata 



- 

with four orders, Bryozoa, including the Vorticellae, Bra- 

■ 



2d Class : Gasteropoda; 

>poda proper. 

3d Class : Cephalopoda; 

The most objectionable modification 



with three orders, Pteropoda, Heteropoda, and Gas- 



with two orders, Tetrabranchiata and Dibranchiat 



duced in the general classificatio 



of 



the animal kingdom, since the appearance of Cuvier 



Reg 



Animal, seems to 



me 



to be the establishment of a distinct branch, now very generally admitted 
under the name of Vermes, including the Annulate, the Helminths, the Rotifera, 



and as Leuckardt would have it, the Bryozoa also. 



It 



was certainly an improve- 



ment upon Cuvier's system, to remove the Helminths from the type of Radiates, 



but it was at the same time 



as truly a retrograde step to separate the Annelides 



from the branch of Articulata. The most minute comparison does not lead to the 
discovery of a distinct plan of structure, uniting all these animals into one natural 



primary group 



What holds them together 



and keeps them at a distance 2 from 

+ 

other groups is not a common plan of structure, but a greater simplicity in their 



I 



1 


















M 



Q ' 












■ 
























I i 



rli 









i i 














































i! 







' i 






























1 Chap. I., Sect. 18, p. 72. 



Chap. II., Sect. 7, p. 171, 172 



24 



/ 












. 



















































. 

























ill 





















1 



. 































. . 



186 



ESSAY ON CLASSIFICATION 



Part I. 



organization. 1 In bringing these animals together, naturalists make again the same 
mistake which Cuvier committed, when he associated the Helminths with the 



Radiates 



nly in another way and upon a g 



scale. 2 The Bryozoa are as it 



were depauperated Mollusks, as Aph 



and Alchemilla are depauperated Ro 



Rotifera are in the same sense the lowest Crustacea; while Helminths and Annelides 
constitute together the lowest class of Articulata. This class is connected by the 
closest homology with the larval states of Insects 
identical, and there exists between 



the 



them 




such 



of their structure is 



uctural differences as con- 




stitute classes 



manner as 



pillars 
the e 



1 Moreover, the Helminths are linked to the Annelides in the same 
the apodal larvae of Insects are to the most highly organized eater- 
It may truly be said that the class of Worms represents, in perfect animals, 



mbry 



states of the higher Articulata 



The two other classes of this 



branch are the Crustacea and the Insects, respecting the limits of which, as much 

* 

has already been said above, 4 as is necessary to state here. 

The classification of the branch of Articulata may, therefore, stand thus: 

1st Class : "Worms; with three orders, Trematods, (including Cestods, Planarise, 

and Leeches,) Nematoids, (including Acanthocephala and Gordiacei,) and Annelides. 
2d Class : Crustacea; with four orders, Rotifera, Entomostraca, (including 



Cirripeds,) Tetradecapods, and Decapods. 



3d Class : 



Insects; with three orders, Myriapods, Arachnids, and Insects 



proper 



There is not a 



dissenting voice 



among anatomists respecting the natural limits 

F 

of the Vertebrata, as a branch of the animal kingdom. Their character, however, 
does not so much consist in the structure of their backbone or the presence of 



a dorsal cord, as in the general 




of that structure, which exhibits a cavity 



above and a cavity below a solid axis. These two cavities are circumscribed by 
complicated arches, arising from the axis, which are made up of different systems 
of organs, the skeleton, the muscles, vessels, and nerves, and include, the upper 
one the centres of the nervous system, the lower one the different systems of 
organs by which assimilation and reproduction are carried on. 

The number and limits of the classes of this branch are not yet satisfactorily 
ascertained. At least, naturalists do not all agree about them. For my part, I 
believe that the Marsupialia cannot be separated from the Placental Mammalia, 
as a distinct class, since we observe, within the limits of another type of Verte- 
brata, the Selachians, which cannot be subdivided into classes, similar differences in 
the mode of development to those which exist between the Marsupials and the other 



1 See above, Chap. I., Sect. 18, p. 74-78 

2 Compare Chap. II., Sect. 1, p. 142. 



8 Compare Chap. II., Sect. 2, p. 145. 
4 Compare Chap. I., Sect. 18, p. 78-80 









. 



• 



' 













u b J 









NT 




4_ 








.■ 




Chap. III. 



EARLY ATTEMPTS. 



187 



Mammalia. But I hold, at the same time, with other naturalists, that the Batrachia 
must be separated, as a class, from the true Reptiles, as the characters which distin- 
guish them are of the kind upon which classes are founded. I am also satisfied 
that the differences which exist between the Selachians, (the Skates, Sharks, and 
Chimaarge,) are of the same kind as those which distinguish the Amphibians from- 

» 

the Reptiles proper, and justify, therefore, their separation, as a class, from the 
Fishes proper. I consider also the Cyclostomes as a distinct class, for similar 
reasons ; but I am still doubtful whether the Ganoids should be separated also from 
the ordinary Fishes. This, however, cannot be decided until their embryological 

* 

development has been thoroughly investigated, though I have already collected data 
which favor this view of the case. Should this expectation be realized, the branch 
of Vertebrata would contain the following classes: 



1st Class: Myz 
2d Class: Fish 



proper 



with two orders, Myxinoids and Cyclostome 
: with two orders, Ctenoids and Cycloids. 



3d Class : Ganoids; with three orders, Coelacanths, Acipenseroids, and Sauroids 
and doubtful, the Siluroids, Plectognaths, and Lophobranches. 



4th Class 
5th Class 
6th Class 
Testudinata. 



Selachi 
Amphib 

Reptile 



5: with three orders, Chimaaraa, Galeodes, and Batides. 
is; with three orders, Caeciliae, Ichthyodi, and Anura, 
with four orders, Serpentes, Saurii, Rhizodontes, and 



4 ^ 



7th Class: Birds; with four orders, Natatores, Grallaa, Rasores, and Insessores, 

(including Scansores and Accipitres.) 

8th Class: Mammalia; with three orders, Marsupialia, Herbivora, and Car- 



nivora. 



I shall avail myself of an early opportunity to investigate more fully how 
far these groups of Vertebrata exhibit such characters as distinguish classes, and I 
submit my present impressions upon this subject, rather as suggestions for further 
researches, than as matured results. 






SECTION 



II 



EAKLY ATTEMPTS TO CLASSIFY ANIMALS. 



■ 

So few American naturalists have paid special attention to the classification 



of the animal kingdom in g 



that I deem it necessary to allude to the 



different principles which, at different times, have guided zoologists in their attempts 
to group animals according to their natural affinities. This will appear the 



more 






























.' i 



8 



. : 










































4 i 
I ' 









\ I 


















































i 














* 





























I 



























/ 












■ 







































































I 









I? 

■ 






































188 



ESSAY ON CLASSIFICATION. 



Part I 



acceptable, I hope, since few of our libraries contain even the leading works of 
our science, and many zealous students are thus prevented from attempting to study 
what has thus far been done. 

Science has begun, in the introduction of names, to designate natural groups 
of different value with the same vagueness which still prevails in ordinary lan- 
guage in the use of class, order, genus, family, species; taking them either as 
synonyms or substituting one for the other at random. Linnaeus was the first 



to 



'g 



upon naturalists precision in the use of four kinds of groups in natural 



history, which he calls classes, orders, genera, and species 



Aristotle, and the ancient philosophers generally, distinguished only two kinds 



of 



groups among animals 



and 



(s 



and species 



But the term g 



had a most 



qual meaning, applying 



at times indiscriminately to any extensive 
group of species, and designating even what we now call classes as well as any 
other minor group. In the sense of class, it is taken in the following case : 



■ 

ley (o 8s ytvog, olov oqvi&u, xal lidvv, (Arist. Hist. Anim., Lib. 




Chap. I.,) while *l8og is 



generally used for species, as the following sentence shows : xal imw «% nleico ix&vmv 
ml oqvi&cov, though it has occasionally also a wider meaning. The sixth chapter of 
the same book, is the most important in the whole work of Aristotle upon this 
subject, as it shows to how many different kinds of groups the term ytvog is applied. 
Here, he distinguishes between ymj ptyima and y&vi\ ^ydla and ytvog shortly, rtvrj 8s 



fityiora rcov £c6cov, elg a 8iaiQefrai rdlla £c3>a, rd8* I artv •. h ph oqvi&cov, tv 8' Ix&vcov, alio 8s xrpovg 



Jlllo 8s ytvog tarl to rav oarQaxoStQficov Tcov 8s loutwv 






L.cocov om sari ra ytvrj [isydla • ov 



ya Q 



TtsQisisi nolla ei'8r] & sl8og, . ... rd 8' i%u ph, all' dvcovvpa. This is further insisted upon anew : 

rod 8s ytvovg raiv rerQUTtoScov £boow y.ai ^cocoroxcov ei'8r] ph slat nolla, dvc6vv[A,a 8s. Here sl8og has 

evidently a wider meaning than our term species, and the accurate Scaliger translates 
it by genus medium, in contradistinction to ytvog, which he renders by genus summum. 
Eldog, however, is generally used in the same sense as now, and Aristotle already 
considers fecundity as a specific character, when he says, of the Hemionos, that 
it is called so from its likeness to the Ass, and not because it is of the same 
species, for he adds, they copulate and propagate among themselves: ai xalovvrai 



TjfXlOVOl 



8i oiioiorrjra, ovx ovaai 



artlwg 



ro 



avrb el-dog • xai yaQ 6%evovrai uai ysvvcovrai t% dlltjlcov. 



In 



another passage it applies, however, to a group exactly identical with our modern 
genus Equus : 



sttsl tanv tv n ytvog uai titt rolg s%ovcl xairijv, loyovQOig ^alov/xtvoig, olov 



ytvog 



ITtTlCp y.ai 

it 



ovuj ua\ ami xal yivvco not ivvco xal roig tv Jlvqici xalov[xtvatg tjfitovoig. 



v.ai oqsX y.ai 



i 



Aristotle cannot be said to have proposed any regular classification. He speaks 
constantly of more or less extensive groups, under a common appellation, evidently 
considering them as natural divisions ; but he nowhere expresses a conviction that 



these groups may be 



ged methodically so as to exhibit the natural affinities 



of animals. Yet he frequently introduces his remarks respecting different animals 



\ 





























r. 










1 






/ 






Chap. III. 



PERIOD OF LINN^US. 



189 



in such an order and in such connections as clearly to indicate that he knew their 

■ 

relations. When speaking of Fishes, for instance, he never includes the Selachians. 



Afte 



Aristotle, the systematic classification of animals make 



no 



■ 

two thousand y 
precise meaning 

( genus proximmn, ) 



5, until L 
the terms 



introduces new distinct 



and 



(ff 



pro 
ignis 



for 



a more 



order, {genus intermedium,) genus 



and species, the two first of which are introduced by him for the 



■ 

first time as distinct groups, under these names, in the system of Zoology 






SECTION III. 



PERIOD OF LINNAEUS. 



■ 

When looking over the "Systema Nature" of Linnaeus, taking as the standard 

the twelfth edition, which is the last he edited himself, 

■eat was the influence of that 



of our appreciation even 
it is 



hardly possible, in our day, to realize how g 



work upon the prog 



of Zoology. 1 And yet it acted like magic upon the 



and stimulated to exertions far 



passing 



age 
any thing that had been done in pre 



ceding centuries. 



Such a 



result must be ascribed partly to the circumstance that 



he was the first man who ever 
definite form, what he cons 



* L 

onceived distinctly the idea of expressing in a 



the 



g 



comprehen 



dered to be a system of nature, and partly also to 
simplicity, and clearness of his method. Discarding 



his system every thing that could not 



ly be ascertained, he for the first time 



divided the animal kingdom into distinct classes, characterized by definite features 
he also for the first time introduced orders into the system of Zoology beside 



g 



and species, which had been 



guely distinguished before. 2 And though 



he did not even attempt to define the characteristics of these different kinds of 




groups, it is 
subdivisions of a 



from his numerous writings, that he considered them all 



as 



sly more 
number of animals, agreeing in more 



mited value, embracing a larger or smaller 
less comprehensive attributes. 



He 



expresses 



1 To appreciate correctly the successive improve- reprints of the second ; the seventh, eighth, and ninth 
ments of the classification of Linnams, we need only are reprints of the sixth ; the eleventh is a reprint of 

» 



compare the first edition of the " Systema Naturas 



» 



the tenth; and the thirteenth, published after his 



published in 1735, with the second, published in 1740, death, by Gmelin, is a mere compilation, deserving 
the sixth published in 1748, the tenth published in 
1758, and the twelfth published in 1766, as they are 



little confidence. 



See above, Sect. 2, p. 188. The 



ytvt] fisyicxa 



the only editions he revised himself. The third is of Aristotle correspond, however, to the classes of 



only a reprint of the first, the fourth and fifth are 



Linnaeus ; the yethj [teydla to his orders. 







1 










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h 



,. i 


















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■ 









































































































'"■ ■ 









190 



SAY ON 



ss 



Part I. 






























It 




























his views of these relations b 



classes, orders, genera, species, and varieties, 



by comparisons, in the following manner 



i 



Classis. 



Genu 



s summura 



Provincial. 

Legiones. 



Ordo. 
Genus intermedium 
Territoria. 
Cohortes. 



Genus. 
Genus proximum 
Paroeciae. 
Manipuli. 



• Species. 
Species. 
Pagi. 
Contubernia 



Varietas. 
Individuum. 
Domicilium 
Miles. 



His arrangement of the animal kingdom is presented in the following diagram 



compiled from the twelfth edition, published in 1766 



CLASSIFICATION OF LINN-EUS. 



Cl. 1. Mammalia. 



Ord. Primates, Bruta, Ferae, Glires, Pecora, Bellu^e, Cete 



Cl. 2. A v e s . Ord. Accipitres, Picse, Anseres, Grallae, Gallinse, Passeres. 

Cl. 3. Amphibia. Ord. Keptiles, Serpentes, Nantes. 

Cl. 4. Pisces. Ord. Apodes, Jugulares, Thoracici, Abdominales. 

Cl. 5. Insecta. 



Ord. Coleoptera, Hemiptera, Lepidoptera, Neuroptera, Hymenoptera, Diptera, 



Aptera. 
Cl. 6. Vermes. 



Ord. Intestina, Mollusca, Testacea, Lithophyta, Zoophyta. 



In the earlier editions, np to the tenth, the class of Mammalia was called 
Quadrnpedia, and did not contain the Cetaceans, which were still included among 



the Fishes 
respecting 

by Linnaeus 



There seems never to have existed any discrepancy among naturalists 
the natural limits of the class of Birds, since it was first characterized 
in a manner which excluded the Bats and referred them to the class 
of Mammalia. In the early editions of the "Systema Naturae," the class of Reptiles 
embraces the same animals as in the systems of the most recent investigators ; 
but since the tenth edition, it has been encumbered with the addition of the 



£ 



and semicartilag 



Fishes, a retrograde movement suggested by some 



inaccurate observations of Dr. Garden. The class of Fishes is very well limited 



in the early editions of the Systema, with the 



pt 



of the admission of the 



Cetaceans, (Plag 



which were correctly referred to the class of Mammalia 



in 



the tenth edition. In the later editions, however, the Cyclostoms, Plagiostoms 



ChimaeraB, Sturg 



Lophioids, Discoboli, Gymnodonts, Scleroderma, and Loph 



branches are excluded from it and referred to the class of Keptiles. The class 
of Insects, 2 as limited by Linnaeus, embraces not only what are now considered as 



1 See Systema Naturae, 12th edit., p. 13. 

2 Aristotle divides this group more correctly than 
Linnaeus, as he admits already two classes, (ysvtj 
uiyiaza) among them, the Malacostraca, (Crustacea,) 



He seems also to have understood correctly the 
natural limits of the classes of Mammalia and Kep- 
tiles, for he distinguishes the Viviparous and Ovipa- 
rous Quadrupeds, and nowhere confounds Fishes with 



.) Hist. Anim., Chap. VI. Keptiles. Ibid. 


















■ 






it Si 
























Chap. III. 



PERIOD OF LINN^US. 



191 



it 



i 



< 



Insects proper, but also the Myriapods, the Arachnids, and the Crustacea; 
corresponds more accurately to the division of Arthropoda of modern systematists. 
The class of Worms, the most heterogeneous of all, includes besides all Radiata 



or Zoophyt 



and the Mollusks of modern writers, also the Worms, intestinal and 



free, the Cirripeds, and one Fish, (My 
order in this chaos. 



It was left for C 



1 



to introduce 



Such 

■ 

the most 



with 



excellences and short-comings, the classification which has 



g 



pected and unprecedented impulse to the study of 



gy 



It 



is 



useful to remember how lately even so imperfect a performance could have so 



an influence upon the prog 



great I 

still possible that so 



of science, in order to understand why 



much remains to be done in systemat 



;y. Nothing 



indeed, can be more instructive to the student of Natural History, than a careful 



and minute comparison of the different edit 



of the "Systema Naturae 



of 



Linnaeus, and of the works of Cuvier and other prominent zoologists, in order to 

- 

detect the methods by which real progress 



is made in our science. 



Since the publicat 



of the "Systema Naturae" up to the time when C 



published the results of his anatomical hrv 
fications were, after all, only modifications 



in the systematic 



gement of animals 



influence of his master spirit, and a 



3stigations, all the attempts at new classi- 
of the principles introduced by Linnaeus 
Even his opponents labored under the 
critical comparison of the various systems 



which were proposed for the ar] 

kingdom shows that they were 

under the impression that animals were to be 



angement of single classes or of the whole animal 
framed according to the same principles, namely, 



g 



arranged together into classes, orders 
and species, according to their more or less close external resemblance 



No sooner, however, had Cuvier presented to the scientific world his extensive 



researches 



the internal 



of the whole animal kingdom, than naturalists 



vied with one another in their attempts to remodel the whole classification of 



animals, establishing new 



and introducing all manner of intermediate 



classes, new orders, new genera, describing new species, 

divisions and subdivisions under the 



name of families, tribes, sections, etc. 



Foremost in these attempts was C 



/ 



himself, and next to him Lamarck. It has, however, often happened that the 
divisions introduced by the latter under new names, were only translations 



into 



a more 



systematic form of the results Cuvier had himself obtained from his dis- 
and pointed out in his « Lecons sur l'anatomie compared," as natural divisions, 

Cuvier himself beautifully expresses the 



but without giving them distinct names 



It would be injustice to Aristotle not to mention Speaking, for instance, of the great genera or classes, 



that he understood already the relations of the animals he separates correctly the Cephalopods fro 
united in one class by Linnaeus, under the name of other Mollusks, under the name of Malak 
Worms, better than the great Swedish naturalist. Anim., Lib. I., Chap. VI. 



the 



Hist. 



w 















.■ 









T 



















i 






B I 






I , 












i \ 




































1 






















































































II 



J 





^^E 













I 



X 






















192 



ESSAY ON CLASSIFICATION 



Part I 






, 



I 













































influence which his anatomical 



g 



had 



np 



Zoology, and how the 



improvements m classification have contributed to advance comparative anatomy, 
when he says, in the preface to the "Eegne Animal," page vi. : "Je dus done, et 

prit un temps considerable, je dus faire marcher de front 



cette 



obligation me 



l'anatomie et la zoologie, les dissections et le classement; chercher dans mes pre- 
mieres remarques sur l'organisation, des distributions meilleures; m'en servir pour 

* 

arriver a des remarques nouvelles; employer encore ces remarques a perfectionner 
les distributions; faire sortir enfin de cette fe'eondation mutuelle des deux sciences 

■ 

Fune par l'autre, un systeme zoologique propre a servir d ' introducteur et de guide 
dans le champ de l'anatomie, et un corps de doctrine anatomique propre a servir 



de developpement et d'expl 
Without enterh 



au system 



gique 



entering into a detailed account of all that was done in this period 
towards improving the system of Zoology, it may suffice to say, that before the 



first decade of this century had passed, more than 



many classes as Linnaeus 



r 

adopted had been characterized in this manner. These classes are: the Mollusks 
Cirripeds, Crustacea, Arachnids, Annelids, Entozoa, (Intestinal Worms,) Zoophytes 



Radiata, Polyps, and Infusoria. Cuvier 1 admitted at first only eight classes, Dume*ril 2 
nine, Lamarck 3 eleven and afterwards fourteen. The Cephalopoda, Gasteropoda, and 
Acephala, first so named by Cuvier, are in the beginning considered by him as 
orders only in the class of Mollusks ; the Echinoderms also, though for the first 
time circumscribed by him within their natural limits, constitute only an order of 
the class of Zoophytes, not to speak of the lowest animals, which, from want of 
knowledge of their internal structure, still remain in great confusion. In this rapid 
sketch of the farther subdivisions which the classes Insecta and Worms of Linnaeus 
have undergone under the influence of Cuvier, I have not, of course, alluded to 
the important contributions made to our knowledge of isolated classes, by special 

* 

writers, but limited my remarks to the works of those naturalists who have con- 
sidered the subject upon the most extensive scale. 

Thus far, no attempt had been made to combine the 
into more comprehensive divisions, under a higher point of view, beyond that of 
dividing the whole animal kingdom into Vertebrata and Invertebrata, a division 
which corresponds to that of Aristotle, into £«<* facufia and £«« avcupa. All efforts 
were rather directed towards establishing a natural series, from the lowest Infusoria 
up to Man ; which, with many, soon became a favorite tendency, and ended by 
being presented as a scientific doctrine by Blainville. 



classes among themselves 


















t 



1 Cuvier, (G.,) Tableau elementaire de l'Histoire 
naturelle des Animaux, Paris, 1798, 1 vol. 8vo. 



3 Lamarck, (J. B. de,) Systeme des Animaux 
sans Vertebres ou Tableau general, etc., Paris, 1801, 



Dumeril, (A. M. C.,) Zoologie analytique, etc., 1 vol. 8vo. — Histoire naturelle des Animaux sans 



Paris, 1806, 1 vol. 8vo. 



Vertebres, etc., Paris, 1815-1822, 7 vols. 8vo. 






K ■ 



•mi 



*« 













«^. 










Chap. III. 



PERIOD OF CUYIEE. 



193 




i 



u 



■I 



5 









^M 



1 

I 


















■ 






SECTION IV 



PERIOD OF CUVIER, AND ANATOMICAL SYSTEMS. 



The most important period in the history of Zoology begins, however, with the 



year 1812, when Cuvier laid before the Academy of Sciences in Paris the results 

upon the more intimate relations of certain classes of the 
another, 1 which had satisfied him that all animals are con- 
it were, cast in four different moulds. 



of his investigations 

■ 

animal kingdom to one 



structed 



upon 



four different plans, or, as 



A 



more 



gg 



view 



ciation of 



g 



- 

results which 



nly 



of the subject never was presented before to the appre- 
and, though it has by no means as yet produced all the 
re to flow from its further consideration, it has already led 



the most unquestionable improvements which classification in general has made 



since 



the days of Aristotle, and, if I am not greatly mistaken, it is 



nly 



m as 



far as that fundamental principle has been adhered to that the changes proposed 
in our systems, by later writers, have proved a real progress, and not as many retro- 
grade steps. 

This great principle, introduced into our science by Cuvier, is expressed by him 



in these memorable words: "Si 



l'on considere le regne 



cipes que nous venons 



de 



poser 



? 



en se 



animal d'apres les prin- 
de*barrassant des prejuges e*tablis sur les 

divisions anciennement admises, en n'ayant egard qu'a l'organisation et a la nature 

leur grandeur, a leur utility, au plus ou moins de 

a toutes les autres circonstances accessoires, on 



des animaux, et non 



pas a 



connaissance que nous en avons, ni 



trouvera qu'il existe quatre formes principales, quatre plans gene'raux, si l'on peut 
s'exprimer ainsi, d'apres lesquels tous les animaux 



semblent 



avoir ete modeles et 



dont les divisions ulteneures, de quelque titre que les naturalistes les aient deco- 
des modifications assez le*geres fondees sur le developpement ou 



rees, ne 



sont que 



1' addition de quelques parties, qui ne changent rien a 1' essence du plan." 



It 



is 



therefore incredible to me how, in presence of such explicit expressions, 

he is still occasionally, as favoring a division of 

Invertebrata. 2 Cuvier, moreover, was the 
of all the divisions he adopts in his 
system; and this constitutes further a great and important step, even though he 



- 

Cuvier can be represented, as 

the animal kingdom into Vertebrata and 

first to recognize practically the inequality 



may 



not have found the correct measure for all his groups 



For 



we must remem- 



ber that at the time he wrote, naturalists were bent upon establishing one con- 












! I 


















! 









ii 
















II ii 




























































Mu 



2 Ehrenberg, (C. G.,) Die Corallenthiere des 



Paris, 1812. 



Me ere s 



25 















I 























r 








































































1} 



















fc 















\ 



194 



ESSAY ON CLASSIFICATION. 



Part I. 



tinual uniform series to embrace all animals, between the links of which it 



was 




pposed there were no 



qual intervals. The watchword of their school was : 



JVatut 



facit sattum. They called their system la chaine des etres. 



The views of Cuvier led him to the followin 



kingdom 



6 



gement of the animal 



CLASSIFICATION OF CUVIER. 



First Branch. Animalia Vertebrata. 

Cl. 1. Mammalia. 



Orders : Bimana, Quadrumana, Carnivora, Marsupialia, Rodentia, Eden- 
tata, Pachydermata, Ruminantia, Cetacea. 
Cl. 2. Birds. Ord. Accipitres, Passeres, Scansores, Gallinae, Grallae, Palmipedes. 
Cl. 3. Reptilia. Ord. Chelonia, Sauria, Ophidia, Batrachia. 

■ 

Cl. 4. Fishes. 1st Series : Fishes proper. Ord. Acanthopterygii ; — Abdominales, Sub- 

brachii, Apodes ; — Lophobranchii, Plectognathi ; 2d Series : Chondropterygii. 
Ord. Sturiones, Selachii, Cyelostomi. 2 



Second Branch. Animalia Mollusca. 

- 

Cl. 1. Cephalopoda. No subdivisions into orders or families. 

Cl. 2. Pteropoda. No subdivisions into orders or families. 

Cl. 3. Gasteropoda. Ord. Pulmonata, Nudibranchia, Inferobranchia, Tectibranehia, Hetero- 

poda, Pectinibranchia, Tubulibranchia, Seutibranchia, Cyclobranchia. 
Cl. 4. Acephala. Ord. Testacea, Tunicata. 
Cl. 5. Brachiopoda. No subdivisions into orders or families. 

L 

Cl. 6. Cirrhopoda. No subdivisions into orders or families. 



Third Branch. Animalia Articulata. 

■ ■ 

Cl. 1. Annelides. Ord. Tubicolae, Dorsibranchiae, Abranchiae. 

Cl. 2. Crustacea. 1st Section: Malacostraca. Ord. Decapoda, Stomapoda, Amphipoda, 

Laemodipoda, Isopoda. 2d Section: Entomostraca. Ord. Branchiopoda, Poecilopoda, 

Trilobitae. 
Cl. 3. Arachnides. Ord. Pulmonariae, Tracheariae. 

Cl. 4. Insects. Ord. Myriapoda, Thysanura, Parasita, Suctoria, Coleoptera, Orthoptera, 

Hemiptera, Neuroptera, Hymenoptera, Lepidoptera, Rhipiptera, Diptera. 



Fourth Branch. Animalia Radiata. 

Cl. 1. Echinoderms. Ord. Pedicellata, Apoda. 

■ 

Cl. 2. Intestinal Worms. Ord. Nematoidea, (incl. Epizoa and Entozoa,) Parenchymatosa 
Cl. 3. Acalephae. Ord. Simplices, Hydrostaticae. 



Cl. 4. Polypi. (Including Anthozoa, Hydroids, Bryozoa, Corallinae, and Spongia3.) 

Carnosi, Gelatinosi, Polypiarii. 
Cl. 5. Infusoria. 



Ord. 



Ord. Rotifera and Homogenea, (including Polygastrica and some Alg^e.) 






















1 Le Kegne animal distribue d'apres son organisation, Paris, 
1829, 2de edit. 5 vols. 8vo. The classes of Crustacea, Arach- 
nids, and Insects have been elaborated by Latreille. For the 
successive modifications the classification of Cuvier has under- 



gone, compare his Tableau elementaire, q. a., p. 192, his paper, 
q. a., p. 193, and the first edition of the Kegne animal, published 
in 1817, in 4 vols. 8vo. 

2 Comp. Eegn. Anim., 2de edit., 2d vol., p. 128 and 383. 










MM 















' 













Chap. 



PERIOD OF CUVIER. 



195 



we consider the 



example 



to our knowledg 



gical systems of the past century, that of Lin- 
instance, and compare them with more recent ones, that of Cuvier for 

have added little 
; not merely in 



cannot overlook the fact, that 



when discove 



the 



ubj 



is treated in a different manner 



consequence of the more extensive information respecting the internal structure of 
animals, but also respecting the gradation of the higher groups. 

Linnaeus had no divisions of a higher « order than classes. Cuvier introduced, 

eat divisions, which he called " embranchemens" or branches. 



for the first time, four 



g 



many as 



under which he arranged his classes, of which he admitted three times as 
Linnaeus had done. 

■ 

Again, Linnaeus divides his classes into orders; next, he introduces genera, and 
finally, species; and this he does systematically in the same gradation through all 



classes, so that each of his six classes is 



subdivided into orders, and these into 



genera with their species. Of families, as now understood, Linnaeus knows nothing. 



The classification of Cuvier presents no such regularity in its framework. 



In 



some classes he proceeds, immediately after presenting their characteristics, to the 
enumeration of the genera they contain, without grouping them either into orders 
or families. In other classes, he admits orders under the head of the class, and 
then proceeds to the characteristics of the genera, while in others still, he admits 
under the class not only orders and families, placing always the family in a sub- 



ordinate position to the order, but also a 



number of secondary divisions which 



he calls sections, divisions, tribes, etc., before he reaches the genera and species. 



With reference to the genera again, we 



find marked discrepancies in different 



classes. Sometimes a genus is to him an extensive group of species, widely differ- 
ing one from the other, and of such genera he speaks as " grands genres ; " others 

without farther sub- 
divisions, while still others are subdivided into what he calls sub-genera, and this 



are limited in their extent, and contain homogeneous species 



is usually the case with his "great genera." 

The gradation of divisions with Cuvier varies then with his classes, some classes 
containing only genera and species, and neither orders nor families nor any other 
subdivision. Others contain orders, families, and genera, and besides these, a variety 
of subdivisions of the most diversified extent and significance. This remarkable 
inequality between all the divisions of Cuvi 

■ 

state of Zoology and of zoological museums 
determination to admit into his work or 



is 



no doubt, partly owing to the 




at the time he wrote, and to his 

representatives of the animal 



such 



kingdom 



he could to a 



self 



but it is also 



pa 



grea 
to b 



or less extent examine anatomically for him 



ascribed to his conviction, often 



pressed, that 



there is no such uniformity or regular serial gradation among animals 

* 

naturalists attempted to introduce into their classifications. 



as many 




< 







































i 

































i 






i 


























































J ] ; 
























































































I 




— "" ■ w 














196 



ESSAY ON CLASSIFICATION. 



Part I 



CLASSIFICATION OF LAMAECK. 



Histoire naturelle des Animaux sans vertebres, etc., Paris, 1815-1822, 7 vols. 8vo. — A second edition with notes has been pub- 
lished by Messrs. DesHayes and Milne-Edwards, Paris, 1835-1843, 10 vols. 8vo. — For the successive modifications this classi- 
fication has undergone, see also: Systeme des animaux sans vertebres, etc., Paris, 1801, 8vo. — Philosophie zoologique, etc., Paris, 
1809, 2 vols. 8vo. — Extrait du Cours de Zoologie du Museum d'Histoire naturelle, etc., Paris, 1812, 8vo. 






























I 











































INVERTEBRATA. 



I. Apathetic Animals. 

i 

Cl. 1. Infusoria. Ord. Nuda, Appendiculata. 

Cl. 2. Polypi. Ord. Ciliati (Rotifera), Denudati (Hydroids), 

Vaginati (Anthozoa and Bryozoa), and Natantes (Crinoids, 

and some Halcyonoids.) 

Cl. 3. Radiaria. Ord. Mollia ( Acalephae) , Echinoderms, (includ- 
ing Holothuriae and Actiniae.) 

Cl. 4. Tunicata. Ord. Bothryllaria (Compound Ascidians), 

Ascidia, (Simple Ascidians.) 



Cl. 5. Vermes. 



Molles and Rigiduli (Intestinal Worms 



Gordius), Hispiduli (Nais), Epizoaria^ (Epizoa, Lernseans.) 

II. Sensitive Animals. 

Cl. 6. Insects. (Hexapods.) Ord. Aptera, Diptera, Hemiptera, 

Lepidoptera, Hymenoptera, Nevroptera, Orthoptera, Cole- 
optera. 
Cl. 7. Arachnids. Ord. Antennato-tracheales (Thysanura and 

■ 

Myriapoda), Exantennato-tracheales and Exantennato-bran- 

chiales (Arachnids proper.) 
Cl. 8. Crustacea. Ord. Heterobranchia (Branchipoda, Isopoda, 

Amphipoda, Stomapoda) and Homobranchia (Decapoda.) 
Cl. 9. Annelids. Ord. Apoda, Antennata, Sedentaria. 
Cl. 10. Cirripeds. Ord. Sessilia and Pedunculata. 
Cl. 11. Conchifera. Ord. Dimyaria, Monomyaria. 
Cl. 12. Mollusks. Ord. Pteropoda, Gasteropoda, Trachelipoda, 



Cephalopoda, Heteropoda. 



VERTEBRATA. 



> 



Do not feel, and move 
only by their excited irri- 
tability. No brain, nor 
elongated medullary mass ; 
no senses ; forms varied ; 

■ 

rarely articulations. 



■ 

Feel, but obtain from 
their sensations only per- 
ceptions of objects, a sort 
of simple ideas, which they 
are unable to combine to 
obtain complex ones. No 
} vertebral column ; a brain 
and mostly an elongated 
medullary mass ; some dis- 
tinct senses ; muscles at- 
tached under the skin ; 
form symmetrical, the parts 
being in pairs. 



III. Intelligent Animals. 

Cl. 13. Fishes. 
Cl. 14. Reptiles. 
Cl. 15. Birds. 
Cl. 16. Mammalia 



1 



V 



Feel ; acquire preservable ideas ; perform with them oper- 
ations by which they obtain others ; are intelligent in different 
degrees. A vertebral column ; a brain and a spinal marrow ; 
distinct senses; the muscles attached to the internal skeleton; 
form symmetrical, the parts being in pairs. 



It 



is not easy to appreciate 



ctly the system of Lamarck, as it combines 



abstract 



ptions with structural considerations, and an artificial endeavor to 



arrange all animals in continuous series. The primary subdivision of the animal 



kingdom 



into Invertebrata and Yertebrata 



i 



ponds, as I have stated above 






1 









r*~ 












See, above, Chap. 2, Sect. 1, p. 138. 



















! i 



in 












Chap. III. 



PERIOD OF CUVIER. 



197 



that of A 



and M 



of Aristotle. The three leading groups designated 



under the name of Apathetic, Sensitive, and Intellig 



animals, are an imitation 



of the four branches of Cuvier; but, far from resting upon such a definite idea 



as the divisions of Cuvier, which involve a 



pecial 




of structure, they are 



founded upon the assumption that the psychical faculties of animals 



gradation, which, when applied as a principle of classification 



rial 



'tainly not admis 



sible. 
Worms feel 



To say that neither Infusoria, nor Polypi, nor Eadiata, nor Tunic 



nor 



nly a very 



assertion. They manifest sensations quite 



as distinctly as many of the animals included in the second type which are called 
Sensitive. And as to the other assertion, that they move only by their excited 

* 

irritability, we need only watch the Starfishes to be satisfied that their motions 



are determined by internal impulses and 



by external excitation. 



Modern 



inves- 



tigations have shown that most of them have a nervous system, and many even 



, g; 



of senses. 



The Sensitive animals are distinguished from the third type, the Intellig 



It 



animals, by the character of their sensations. 

tive animals, that they obtain from their sensations 



stated 



ipect 




percept 



to the Sensi- 
of objects, a 



sort of simple ideas which they are 



them complex 



■ 

while the Intellig 



unable to combine so as to derive from 
it animals are said to obtain ideas which 



they may preserve, and to perform with them operati 

* 

at new ideas. They are said to be Intelligent. 



Even 



Lamarck made those 



I doubt whether 



that 



way 



■ 

between the sensations of the Fishes, for 



by which they arrive 
now, fifty years after 
possible to distinguish in 
stance, and those of the 



Cephalopods 



It 



the structure of the animals called Sensitive and Intel! 



gent by Lamarck differs greatly, but a larg 



number of his Sens 



animals 



are 



constructed upon the same plan as many of those he includes among the Apathetic 



they embrace, moreover, two different plans of 



and animal psychology 



is 



tainly not so far advanced as 



to afford the least foundation for the distinc 



tions here introduced. 



Even from his own point of view, his arrangement of the classes is less perfect 



than he might have made 




as 



the Annelids stand nearer to the Worms than 



the Insects, and are very inferior to them. 



Having failed to perceive the value 



of the idea of plan, and having substituted for it that of a more or less com- 
plicated structure, Lamarck unites among his Apathetic animals, Radiates (the Polypi 
and Radiaria) with Mollusks, (the Tunicata,) and with Articulates (the Worms.) 

Articulates (the Insects, Arachnids, Crus- 
tacea, Annelids, and Cirripeds) with Mollusks (the Conchifera, and the Mollusks 



Among the Sensitive animals, he unites 



proper.) Among the Intelligent 



animals, he includes the ancient four classe 



s 



of 



Vertebrates, the Fishes, Reptiles, Birds, and Mammalia. 



i - 



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II 




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198 



ESSAY ON CLASSIFICATION 



Part I. 










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CLASSIFICATION OF DE BLAINVILLE. 1 



1. Sub-Kingdom. Artiomorpha or Artiozoaria. Form bilateral. 

First Type: Osteozoaria. (Vertebrata.) 

Sub-Type : Vivipara. 

Cl. 1. Pi lifer a, or Mammifera. 1st. Monadelphya. 2d. Didelphya. 
Sub-Type : Ovipara. 

Cl. 2. Pennifera, or Aves. 

Cl. 3. Squamifera, or Reptilia. 

Cl. 4. Nudip ell if era, or Amphibia. 
Cl. 5. Pinnifera, or Pisces. 
Anosteozoaria. 
Second Type: Entomozoaria. (Articulata.) 

■ 

Cl. 6. Hexapoda. (Insecta proprie sic dicta.) 
Cl. 7. Octopoda. (Arachnida.) 

Cl. 8. Decapoda. (Crustacea, Decapoda, and Limulus.) 
Cl. 9. Heteropoda. (Squilla, Entomostraca, and Epizoa.) 
Cl. 10. Tetradecapoda. (Amphipoda and Isopoda.) 
Cl. 11. Myriapoda. 
Cl. 12. Chsetopoda. (Annelides.) 
Cl. 13. Apoda. (Hirudo, Cestoidea, Ascaris.) 
Third Type : Malentozoaria. 

Cl. 14. Nematopoda. (Cirripedia.) 

■ 

Cl. 15. Polyplaxiphora. (Chiton.) 

Fourth Type: Malacozoaria. (Mollusca.) * 

Cl. 16. Cephalophora. Dioica, (Cephalopoda and Gasteropoda, p. p.) Herma- 

phrodita and Monoica (Gasteropoda reliqua.) 

Cl. 17. Acephalophora. Palliobranchia (Brachiopoda), Lamellibranchia (Acephala), 

Heterobranchia (Ascidiae.) 

2. Sub-Kingdom. Actinomorpha or Actinozoaria. Form radiate. 

Cl. 18. Annelidaria, or Gastrophysaria (Sipunculus, etc.) 

Cl. 19. Ceratodermaria. (Echinodermata.) 

Cl. 20. Arachnodermaria. (Acalephse.) 

Cl. 21. Zoantharia. (Actinias.) 

Cl. 22. Polypiaria. (Polypi tentaculis simplicibus), (Anthozoa and Bryozoa.) 

Cl. 23. Z o o p h y t a r i a . (Polypi tentaculis compositis), (Halcyonoidea.) 









) 












3. Sub-Kingdom. Heteromorpha or He 



Form irregular. 



Cl. 24. Spongiaria. (Spongiae.) 
Cl. 25. Monadaria. (Infusoria.) 
Cl. 26. Dendrolitharia. (Corallinse.) 

The classification of de Blainville resembles those of Lamarck and Cuvier much 
more than a diagram of the three would lead us to suppose. The first of these 
systems is founded upon the idea that the animal kingdom forms one gradated 

1 De reorganisation des Animaux, Paris, 1822, 1 vol. 8vo. 

■ 





















it 






I 



r 



















. 









Chap. Ill 



PERIOD OF CUVIER 



199 



series; only that de Blainville inverts the order of Lamarck, beginning with the 
highest animals and ending with the lowest. With that idea is blended, to 



some 



the view of Cuvier, that animals are framed upon different plans of 



but so imperfectly has this view taken hold of de Blainville, that instead of 



recognizing 



at the outset these g 




he allows the external form to be 



the leading idea upon which his primary divisions are founded, and thus he divides 



the animal kingdom 



three sub-kingdoms: the first, including his Artiozoa 



with a bilateral form: the second, his Actino 



third, his Heterozoaria, with an irregular form 

The plan of structure is only introduced as a 



ia, with a radiated form, and the 

(the Sponges, Infusoria, and Corallines.) 
secondary consideration, upon which he 

establishes four types among the Artiozoaria: 1st. The Osteozoaria, corresponding to 

sponding I tol Cuvier's Articulata ; 

gested only by the 

: 4th. 



Cuvier's Vertebrata: 2d. The Entomozoaria 



3d. The Malento 



which are a very artificial group 



ty of establishing a transition b 



the Articulata and Mollusca 



The Malacozoaria 
Actinozoaria, corr 



correspondin 
iponds to C 



to Cuvier's Mollusca. The second sub-kingdom 
er's Radiata, while the third sub-kingdom, Hetero- 



zoaria, contains organized beings which for the most part do not belong to the 



animal kingdom. Such at least are his Spongiaria 
Monodaria answer to the old class of Infusoria, about which 



and Dendrolitharia, whilst his 

enough has already 






been said above 



It is 



evident, that what is correct in this general 



borrowed from Cuvier: but it is only 



to de Blainville to say, that 



gement 
in the 



limitation and 



gement of the 



he has 



ments 



Among Vertebrata, for instance, he has 



the class of Amphibia from the true Reptiles, 
the Intestinal Worms from among the Radiata to 



introduced some valuable improve- 

* 

for the first time, distinguished 

He was also the first to remove 

the Articulata: but the establish- 






ment of a distinct type for the Cirripedia and Chitons was a very mistaken con- 
ception. Notwithstanding some structural peculiarities, the Chitons are built essen- 
tially upon the same plan as the Mollusks of the class Gasteropoda, and the 
investigations, made not long after the publication of de Blainville's system, have left 



no doubt that Cirripedia are g 



Crustacea 



The 



pposed transition between 



Articulata and Mollusks, which de Blainville attempted to establish with his typ 



of 



Malento 
If w 



- 
i 

tainly does not exist in nature. 



,pply to the classes of de Blainville the test introduced in the preceding 
chapter, it will be obvious that his Decapoda, Heteropoda, and Tetradecapoda par- 
take more of the character of orders than of that of classes, whilst among Mol- 

•a certainly includes two classes, as he has himself acknowl- 






lusks, his class Cephalophora 

> 

edged in his later works, 

Zoophytaria partake again of the character 



One 



g 



Among Radiata his classes Zoantharia, Polypiaria, and 

of orders and not of those of classes, 
objection to the system of de Blainville is, the useless introduction of so 












I ; 

1 1 
























I 





















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. 


































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, I 





















I 







200 



ESSAY ON CLASSIFICATION 



Part I 



many new names for groups which had already b 



correctly limited and well 



named by his predecessors. He had, no doubt, a desirable object in view in doing 



this, 



he wished to remove some incorrect names : but he extended his reform 



too far when he undertook to change those also which did not suit his system. 














































Ill 










% 


















CLASSIFICATION OF EHRENBERG. 



Man 



- 
* 

are given more fully in the Transactions of the Academy of Berlin for 1836, in the paper q. a., p. 138. 






1st Cycle : Nations. Mankind, constituting one distinct class, is characterized by the equable development of 

all systems of organs, in contradistinction of the 

■ 

2d Cycle : Animals, which are considered as characterized by the prominence of single systems. These are 



divided into ; 



A. Myeloneura 



I. Nutrientia. Warm-blooded Vertebrata, taking 

care of their young. 
Cl. 1. Mammalia. 

■ 

Cl. 2. Birds. 



II. Orphanozoa. Cold-blooded Vertebrata, taking 

no care of their young. 
Cl. 3. Amphibia. 
Cl. 4. Pisces. 



B. Ganglioneura. 



A. Sphygmozoa, Cordata. 



Circulation marked by a heart or pulsating vessels. 

III. Articulata. Real articulation, marked by 

rows of ganglia and their ramifications. 
Cl. 5. I n s e c t a . 
Cl. 6. Arachnoidea. 
Cl. 7. Crustacea (including Entomostraca, 

Cirripedia, and Lernsea.) 
Cl. 8. Annulata. (The genuine Annelids 

exclusive of Nais.) 
Cl. 9. Somatotoma. (Naidina.) 

IV. Mollusc a. No articulation. Ganglia dis- 

persed. 

> 

Cl. 10. Cephalopoda. 

Cl. 11. Pteropoda. 

Cl. 12. Gasteropoda. 

Cl. 13. Acephala. 

Cl. 14. Brachiopoda. 

Cl. 15. Tunicata. (Ascidia^ simplices.) 

Cl. 16. Aggregata. (Ascidiae composite.) 



B. Asphycta, Vasculosa. 
Vessels without pulsation. 



V. Tubulata. No real articulation. Intestine, a 

simple sac or tube. 
Cl. 17. Bry ozoa. 
Cl. 18. Di morphea. (Hydroids.) 

(Rhabdocoela : De- 



Cl. 19. Turbellaria. 



rostoma, Turbella, Vortex.) 

Cl. 20. Nematoidea. (Entozoa, with sim- 
ple intestine ; also Gordius and Anguillula.) 

Cl. 21. Rotatoria. 

Cl. 22. Echinoidea. (Echinus, Holothuria, 
Sipunculus.) 
VI. Racemifera. Intestine divided, or forked, ra- 
diating, dendritic, or racemose. 

Cl. 23. Asteroidea. 

Cl. 24. Acalephae. 

Cl. 25. Anthozoa. 

Cl. 26. Trematodea. (Entozoa with rami- 
fied intestine, also Cercaria.) 

■ 

Cl. 27. Complanata. (Dendrocoela : Pla- 
naria, etc.) 

Cl. 28. Polygastrica. 



















'J^t 








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I I 



: 4 





















Chap. III. 



ANATOMICAL SYSTEMS. 



201 



The system of Zoology, published by Ehrenberg in 1836, presents many new 



views in almost all its peculiarit 



The most striking of its features is the 



ciple laid down, that the type of development of animals is one and the 
from Man to the Monad, implying a complete negation 



prm- 

same 
of the principle advocated 



by Cuvier, that the four primary divisions of the animal kingdom are characterized 

by different plans of structure. It is very natural that Ehrenberg, after havino- 

illustrated so fully and so beautifully as he did, the natural history of so many 
organized beings, which up to the publication 



of his 



g 



were generally 



considered as entirely homog 



after having shown how highly organized and 



complicated the internal structure of many of them is, after having proved the 

n, should! havelbeen lied! to 



these 



mals 



fallacy of the prevailing opinions respecting their origin, 
the conviction that there is, after all, no essential difference b 
which were then regarded as the lowest, and those which were placed at the 

itor, who had just revealed to the 



head of the animal creation. 



The 



g 



astonished scientific world the complicated systems of organs which can be traced 



the 



con- 



in the body of microscopically small Kotifera, must have been led irresistibly tc 
conclusion that all animals are equally perfect, and have assumed, as a natural 
sequence of the evidence he had obtained, that they stand on the same level with one 
another, as far as the complication of their structure is concerned. Yet the diagram 
of his own system shows, that he himself could not resist the internal evidence of 
their unequal structural endowment. Like all other naturalists, he places Mankind 
at one end of the animal kingdom, and such types as have always been considered 
as low, at the other end. 

constitutes, in his opinion, an independent cycle, that of nations, in contra- 



Man 



distinction to the cycle of animals, which he divides 



Myeloneura, those with 



vous marrow (the Vertebrata,) and Ganglioneura, those with ganglia (the Invertebrate 
The Vertebrata he subdivides into Nutrientia, those which take care of their youn 



o 



and Orphan 
true, as th 



those which take no care of their young, though this 



strictly 



o 



are many Fishes and Reptiles which provide as carefully for their 

in another way. 



young; as some of the Birds and 



Mammalia, though they 



do it 



The In vertebrata are subdivided into Sphyg, 



those which have 



a heart 



or 



pulsating vessels, and Asphyda, those in which the vessels do not pulsate. These 

into Articulata with real articulations 



two sections are further subdivided: the first 



and 
the 



rows 



of 



g 



and Mollusks without articulation and with dispersed 



cond 



Tubulata with a simple 



and Racemifera with 



g 



intestine. 



These characters, which Ehrenberg assigns 



a branching 



to his leading divisions, imply 



iarily the admission of a gradation among animals. He thus 



the 



the form in which he expresses the results of his investigations, 

he intends to illustrate by his diagram. The peculiar view of Ehrenb 

26 



gatives, i] 
very principl 



erg, that 






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N 



202 



ESSAY ON CLASSIFICATION. 



Part I. 



all animals are 



qual in the perfection of their organization, might be justified, if 



it was qualified so as to imply a relative perft 



adapted in all to the end 



of their 



ipecial mode of existence. 



As 



no one observer has contributed more 
i the complicated structure of a host 



extensively than Ehrenberg to make known 

of living beings, which before him were almost universally believed to consist of 



a 



simple 



mass of homogeneous jelly, such a view would naturally be expected 



of him. But this qualified perfect 



not what he means. He does not wish 



to convey the idea that all animals are equally perfect in their way, for he states 
distinctly that "Infusoria have the same sum of systems of organs as Man," and 
the whole of his system is intended to impress emphatically this view. The separa- 
tion of Man from the animals, not merely as a class but as a still higher division, 
is especially maintained upon 



that ground. 



The principle of classification adopted by Ehrenberg is purely anatomical ; the idea 



of type is 



rely set aside, as is shown by the respective position of his classes 



The Myeloneura, it is true, correspond to the branch of Vertebrata, and the 
Sphygmozoa to the Articulata and Mollusca; but they are not brought together 
on the ground of the typical plan of their structure, but because the first have 
a spinal marrow and the other a heart or pulsating vessels with or without articula- 
tions of the body. In the division of Tubulata, it is still more evident how the 
plan of their structure is disregarded, as that section embraces Radiata, (the 
Echinoidea and the Dimorphaea,) Mollusca, (the Bryozoa,) and Articulata, (the 
Turbellaria, the Nematoidea, and the Rotatoria,) which are thus combined simply 

L 

on the ground that they have vessels which do not pulsate, and that their intestine 



is a 



simple 



sac or 



tube. 



The Racemifera contain also animals constructed upon 






different plans, united on account of the peculiar structure of the intestine, which 
is either forked or radiating, dendritic or racemose. 

The limitation of many of the classes proposed by Ehrenberg is quite objec- 

■ 

tionable, when tested by the principles discussed above. A large proportion of them 
are, indeed, founded upon ordinal characters only, and not upon class characters. 
This is particularly evident with the Rotatoria, the Somatotoma, the Turbellaria, the 



Nematoidea 



Trematodea, and the Compl 



all of which belong to the branch 



of Articulata. The Tunicata, the Aggregata, the Brachiopoda, and the Bry 



are 



also 



only orders of the class Acephala. Before Echinoderms had been so exten- 
sively studied as of late, the separation of the Echinoidea from Asteroidea might 
have seemed justifiable; at the present day, it is totally inadmissible. Even 
Leuckart, who considers the Echinoderms as a distinct branch of the animal king- 
dom, insists upon the necessity of 



uniting them as a natural 



group 



As to the 



Dimorphaea, they constitute a natural order of the class Acalephge, which is generally 
known by the name of Hydroids. 









■ 













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1 



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Chap. III. 



ANATOMICAL SYSTEMS. 



203 



CLASSIFICATION OF BURMEISTER. 



The following diagram is compiled from the author's Geschichte der Schopfung, Leipzig, 1843, 1 vol. 8vo 

Type I. Irregular Animals. 

1st Subtype. Cl. 1. Infusoria. 
Type II. Regular Animals. 

- 

2d Subtype. Cl. 2. Polypina. Ord. Bryozoa, Anthozoa. 

- 

3d Subtype. Cl. 3. R a d i a t a . Ord. Acalephse, Echinodermata, Scytodermata. 

Type III. Symmetrical Animals. 
4th Subtype. Cl. 4. Mollusc a. 



Ord. Perigymna (Tunicata) ; Cormopoda (Acephala) ; Brachio- 



poda, Cephalophora (Pteropoda and Gasteropoda) ; Cephalopoda. 



5th Subtype. Arthrozoa. 



Cl. 5. Vermes. Ord. Helminthes, Trematodes, and Annulati. 

Cl. 6. Crustacea. 1°. Ostracoderma. Ord. Prothesmia (Cirripedia, Siphono- 
stoma, and Rotatoria) ; Aspidostraca (Entomostraca : Lophyropoda, Phyllopoda, 
Pa;cilopoda, Trilobitse.) 2°. Malacostraca. Ord. Thoracostraca (Podoph- 
thalma) ; and Arthrostraca, (Edriophthalma.) 

Cl. 7. A r a c h n o d a . Ord. Myriapoda, Arachnidae. 

Cl. 8. I n s e c t a . Ord. Rhynchota, Synistata, Antliata, Piezata, Glossata, Eleutherata. 



6th Subtype. Osteozoa. (Vertebrata.) 

Cl. 9. Pisces. 

Cl. 10. Amphibia. 

Cl. 11. A ves. 

Cl. 12. Mammalia. 



The general arrangement of the classification of Burmeister recalls that of 
de Blainville; only that the order is inverted. His three types correspond to the 
three subkingdoms of de Blainville: the Irregular Animals to the Heterozoaria, the 
Regular Animals to the Actinozoaria, and the Symmetrical Animals to the Artiozo- 

while his subtypes of the Symmetrical Animals correspond to the types de 

his Artiozoaria, with this important improvement, however, 



ana: 



Blainville admits among 



I 



that the Malentozoaria are suppressed. 



Burmeister reduces, unhappily, the whole 



branch of Mollusks to one single class. The Arthrozoa, on the contrary, in the 
investigation of which Burmeister has rendered eminent service to science, are pre- 
sented in their true light. In his special works, 1 his classification of the Articulata 
is presented with more details. I have no doubt that the correct views he entertains 
respecting the standing of the Worms in the branch of Articulata are owing to his 
extensive acquaintance with the Crustacea and Insects, and their metamorphoses. 



These works are : Beitrage zur Naturgeschichte 



1836. 



Die Organisation der Trilobiten, 



aus ihren 



der Rankenfusser, (Cirripedia,) Berlin, 1834, 1 vol. lebenden Verwandten entwickelt, Berlin, 1843, 1 vol. 

Ray Society, London, 1847, 



4to. 



Handbuch der Entomologie, Berlin, 1832-47, 
5 vols. 8vo. ; Engl, by W. E. Shuckard, London, 



4to. ; Engl, by the 
1 vol. fol. 






























i 







































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204 



ESSAY ON CLASSIFICATION. 



Part I. 



CLASSIFICATION OF OWEN. 



The following diagram is compiled from E. Owen's Lectures on the Comparative Anatomy and 



Physiology of the Invertebrate Animals, 2d edit., London, 1855, 1 vol. 8vo. 
Province. Vertebrata. Myelencephala. (Owen.) 






Cl. Mammalia. 
Cl. A v e s . 

- 

Cl. Rep t ilia. 
Cl. Pisces. On 



The classes Mammalia, Aves, and Eeptilia are not yet included in the second volume 
of the "Lectures," the only one relating to Vertebrata thus far published. 



Malacopt 



Lophobranchii, Ganoidei, Protopteri, Holocephali, Plagiostomi. 
Province. Articulata. Homogangliata. (Owen.) 

Cl. Arachnida. Ord. Dermophysa, Trachearia, Pulmotrachearia, and Pulmonaria. 






Cl. Insecta. 



M 



Ord. Chilognatha and Chilopoda. Subclass : II e x a p o d a . 
Ord. Aptera, Diptera, Lepidoptera, Hymenoptera, Homoptera, Strepsiptera, Nevroptera, Orthop- 
tera, and Coleoptera. 

Cl. Crustacea. Subclass: Entomostraca. Ord. Trilobites, Xiphosura, Phyllopoda, Cladocera, 

ilacostraca. 1°. Edriophthalma. Ord. Lsemodipoda, 




Ostracopoda, Copepoda. 



M 



Isopoda, Amphipoda. 2°. Podophthalma. Ord. Stomapoda, Decapoda. 
Cl. Epizoa. Ord. Cephaluna, Brachiuna, and Onchuna. 

, . * 

Cl. Anne Hat a. Ord. Suctoria, Terricola, Errantia, Tubicola. 
Cl. Cirripedia. Ord. Thoracica, Abdominalia, and Apoda. 
Province. Mollusca. Heterogangliata. (Owen.) 

Cl. Cephalopoda. Ord. Tetrabranchiata and Dibranchiata. 



Cl. Gasteropoda. A. M 



Ord. Apneusta (Koll.), Nudibranchiata, Inferobranchiata, 

Nucleobranchiata, Tubulibranchiata, Cyclo- 



Tectibranchiata, Pulmonata. B. Dioecia. Ord. 

branchiata, Scutibranchiata, and Pectinibranchiata. I 

Cl. Pteropoda. Ord. Thecosomata and Gymnosomata. 

Cl. Lamellibranchiata. Ord. Monomyaria and Dimyaria. 

Cl. Brachiopoda. Only subdivided into families. 

Cl. Tunicata. Ord. Saccobranchiata and Taeniobranchiata. 

* 

Subprovince. Radiaria. 1 

Cl. Echinodermata. Ord. Crinoidea, Asteroidea, Echinoidea, Holothurioidea, and Sipunculoidea 

Cl. Bryozoa. Only subdivided into families. 

Cl. Anthozoa. Only subdivided into families. 

Cl. Acalephae. Ord. Pulmograda, Ciliograda, and Physograda. 

Cl. Hydrozoa. Only subdivided into families. 

"'■■;... 

Subprovince. Entozoa. 

Cl. Coelelmintha. Ord. Gordiacea, Nematoidea, and Onchophora. 

Cl. Sterelmintha. Ord. Taenioidea, Trematoda, Acanthocephala. — Turbellaria. 
Subprovince. Infusoria. 

Cl. Rotifera. Only subdivided into families. 

Cl. Polygastria. Ord. Astoma, Stomatoda. 






* 



Rhizopoda. 



1 In the first edition of the work quoted above, published 
in 1843, the three subprovinces, Eadiaria, Entozoa, and Infu- 
soria are considered as one subkingdom called Kadiata, in 



contradistinction of the subkingdoms, Mollusca, Articulata, 
and Vertebrata, and that subkingdom is subdivided into two 
groups, Nematoneura and Acrita. 












* 










l 












Chap. Ill 



ANATOMICAL SYSTEMS 



205 



The classificat 



with which Owen * introduces his 



Lectures on Comp 



Anatomy" is very instructive, as showing, more distinctly than other modern systems 



the unfortunate 



dency which the consideration of the compl 



of 



has 




ained of 



over the idea of plan 



His 



provinces, it is true, 



jpond 



in the main to the branches of Cuvier, with this marked difference, however that 



distinct province of Radiata coequal with those of Mollusca 

•ovince on a level 



he does not recognize a 

Articulata, and Vertebrata, but only admits Radiaria as a subp 

with Entozoa and Infusoria. Here, the idea of simplicity of structure evidently 



prevails over that of 




as 



the 



bp 



Radiaria, Entozoa, and Infusoria 



embrace, besides true Radiata, the lowest types of two other branches, Mollusks 



and Articulates. On the other hand, his three subp 



pond to the 



first three types of von Siebold ; the Infusoria 2 of Owen embracing the same 
animals as the Protozoa of Siebold, his Entozoa 3 the same as the Vermes, and his 
Radiaria the same as the Zoophyta, with the single exception that 
the Annellata to the province of Articulata, whilst Siebold includes 



Owen refers 



them 



among 



his Vermes. Beyond this the types of Mollusca and Articulata (Arthropoda) of 



the two distinguished anatomists 



Jy 



g 



The position 



gned by Owen 



to the provinces Articulata and Mollusca, not one above the other, but side by 
side with one another, 4 is no doubt meant to express his conviction, that the com- 
plication of structure of these two types does not justify the idea that either 



of them stands higher or 



lower than the other; and this is perfectly correct. 



Several 



group 



established by previous writers as families or orders, are here 



admitted as classes. His class Epizoa, which 



not to be confounded 



th that 



established by Nitzsch under the same name, corresponds exactly to the family 

His class Hydrozoa answers to the order Hydroida of 



calledlLERNEEslby Cuvier. I 

Johnston, and is identical with the class called Dimorph^a by Ehrenberg. 

class Ccelelmintha corresponds to the order of Intestinaux Cavitaires established 



Hi 









1 I have given precedence to the classification 



The Rhizopoda are considered as 



a group 



of Owen over those of von Siebold and Stannius, coequal to Rotifera and Polygastria, on p. 16 of 
Milne-Edwards, Leuckart, etc., because the first edi- * the " Lectures/' but on p. 59, they stand 



as a sub- 



order of Polygastria 

8 The Turbellaria are represented as an inde- 
pendent group, on p. 1 6, and referred as a suborder 
to the Trematoda, on p. 118. 

From want of room, I have been compelled, 
were only added to the second edition in 1855. I in reproducing the classification of Owen in the 
mention this simply to prevent the possibility of preceding diagram, to place his provinces Articulata 
being understood as ascribing to Owen all those sub- and Mollusca one below the other upon my page ; 
divisions of the classes, which he admits, and which according to his views, they should stand on a level 



tion of the " Lectures on Comparative Anatomy " 
was published in 1843 ; but in estimating its features, 
as expressed in the preceding diagram, it should be 
borne in mind that, in the first edition, the classes 
alone are considered, and that the orders and families 



do not appear in the systems considered before his. 



• •• i 

side by side with one another. 






| 



; •! 












■ 









■ 

































! 

I 

I 

























M 





















t ; 












































; ■ 














































! 


















' 










; 









. 

















































II 


















■w*^^^^ 









206 



ESSAY ON CLASSIFICATION. 



Part I. 



by Cuvier, with the addition of Gordius 



while his class Sterelmintha has the 



same circumscript 



the order Intestinaux Parenchymateux of C 



peaking, it should not be understood that the 



Generally 



secondary divisions mentioned by the 
different authors, whose systems I have analyzed here, were established by them. 
They are frequently borrowed from the results obtained by special investigators of 
isolated classes. But it would lead me too far, to enter here into a discussion 
of all these details. 



g 



This 

L Of 



g 



resemblance of the modern systems of Zoology 



very favorable 



times. It would, indeed, be a great mistake to assume, that 



solely 



g to the influence of different authors upon 



one another; it is, on the con- 



trary, to a very g 



extent, the result of our better acquaintance with Nature 



When investigators, at all conversant with the present state of our science, must 



possess 
can no 



ly the same amount of knowledg 



self-evident that their views 



long 



differ so widely as they did when each was familiar 



a part of the subject. A deep 



nly with 



ght 



the animal kingdom must, in the 



end, lead to the conviction that it is not the task of zoologists to introduce order 
among animals, but that their highest aim should be simply to read the natural 



affinities which exist among them 



that the more 



arly 



knowledge embraces 



the whole field of 



£ 



the more closely will our opinions coincide 



As to the value of the classes adopted by Owen, I may further remark that 
recent investigations, of which he might have availed himself, have shown that the 



can no 



Cirripedia and his Epizoa are genuine Crustacea, and that the Entozoa 
longer be so widely separated from the Annellata as in his system. With reference 
to the other classes, I refer the reader to my criticism of older systems, and to 
the first section of this Chapter. 



It 



is a 



gr 



satisfaction for me to find that the views I have advocated in 



the preceding sections, respecting the natural relations of the leading groups of 




the animal kingdom, coincide so clog 
zoologist, Milne-Edwards, lately presei 
views of the natural affinities of animals 



who has 



with the classification of that distinguished 
ted by him as the expression of his present 

He is the only original investigator 



ntly given his unqualified approb 



to th 



primary divisions first 



proposed by Cuvier, admitting, of course, the rectifications among the group of 
secondary rank, rendered necessary by the progress of science, to which he has 
himself so largely contributed. 

As to the classes adopted by Milne-Edwards, I have little to add to what I 



have already stated before, with reference to other classifications 



long 



g the idea of 




that of compl 



Though no 



of structure has still too 



much influence with Milne-Edwards, inasmuch as it leads him to consider as classes, 
groups of animals which differ only in degree, and are therefore only orders. 





























e 













/ 












s 



t 












Chap. Ill 



ANATOMICAL SYSTEMS 



207 



Such are, no doubt, 



his classes of Molluscoids and those of Worms, besides the 
Myriapods and Arachnids. Respecting the Fishes, I refer to my remarks in the 

« 

first section (p. 187) of this Chapter. 



CLASSIFICATION OF MILNE-EDWARDS. 



L * 

The following diagram is drawn from the author's Cours elementaire d'Histoire naturelle, Paris, 1855, 
1 vol. 12mo., 7th edit., in which he has presented the results of his latest investigations upon the classifica- 
tion of the Vertebrata and Articulata; the minor subdivisions of the 
however, are not considered in this work. 1 



Worms, Mollusks 



I. Osteozoaria, or Vertebkata. 



Subbranch. All ant oi dians . 

Cl. Mammalia. 1°. Monodelphya. a. Propria. Ord. Bimana, 
Quadrumana, Cheiroptera, Insectivora, Rodentia, Edentata, Carni- 
vora, Amphibia, Pachydermata, Ruminantia. b. Pisciformia. Ord. 
Cetacea. 2°. Didelphya. Ord. Marsupialia, Monotremata. 

Cl. Birds. Ord. Rapaces, Passeres, Scansores, Galling, 

Grallae, and Palmipedes. 

Cl. Reptiles. Ord. Chelonia, Sauria, Ophidia. 



Subbranch. An all ant oi dians . 

Cl. Batrachians. Ord. Anura, 
Urodela, Perennibranchia, Cascilise. 

Cl. Fishes. 1°. Ossei. Ord. Acan- 
thopterygii, Abdominales, Subbrachii, 

i 

Apodes, Lophobranchii, and Plectog- 
nathi. 2°. Chondropterygii. Ord. Stu- 
riones, Selachii, and Cyclostomi. 



II. Entomozoa, or Annellata. 



Subbranch. Arthr op o da. 

Cl. I n s e c t a . Ord. Coleoptera, Orthoptera, Nevroptera, Hymenoptera, 
Lepidoptera, Hemiptera, Diptera, Rhipiptera, Anoplura, and Thysanura. 



Cl. Myriapoda. Ord. Chilognatha and Chilopoda. 
Cl. Arachnids. Ord. Pulmonaria and Trachearia. 
Cl. Crustacea. 1 



Podophthalmia. 



Ord. Decapoda and Stomapoda. 



2 



Edriophthalma. Ord. Amphipoda, L^modipoda, and Isopoda. 3 



Bran- 



chiopoda. Ord. Ostrapoda, Phyllopoda, and Trilobite. 4°. Entomostraca. Ord. 

Copepoda, Cladocera, Siphonostoma, Lernaeida, Cirripedia. 5°. Xiphosura. 



Subbranch. Ve fmes 
Cl. Annelids. 
Cl. Helminths. 
Cl. Turbellaria 
Cl. Cestoidea. 
Cl. Rotatoria. 



III. Malacozoaria, or Mollusca. 



Subbranch. Mollusks proper 

Cl. Cephalopods. 
Cl. Pteropods. 

x. 

Cl. 'Gasteropoda, 
Cl. Acephala. 



• 



Subbranch. Mo lluscoids. 
Cl. Tunicata. 
Cl. Bryozoa. 



IV. Zoophytes. 



. - 

Subbranch. R adiaria, or Radiata 

- 

Cl. Echinoderms. 

Cl. Acalephs. 

Cl. Corallaria, or Polypi. 



Subbranch. Sarcodaria 
Cl. Infusoria. 
Cl. Spongiaria. 



• 



Ann 






i $ 



■ 









t 












i 















: I 

















: ' 












* 




j • \ 









: 












i ; 









Mi 





























\ 





















I 

: 
































IN 

It 



111 




























































208 



ESSAY ON CLASSIFICATION. 



Part I 






CLASSIFICATION OF VON SIEBOLD AND STANNIUS 






This classification is adopted in the following work : Siebold, (C. Th. v.,) and Stannius, (H.,) Lehrbuch 
der vergleichenden Anatomie, Berlin, 1845, 2 vols. 8vo. A second edition is now in press. 



L Protozoa. 



EVERTEBRATA. 



Cl. 1. Infusoria. Ord. Astoma and Stomatoda. 

Cl. 2. Rhizopoda. Ord. Monosomatia and Polysomatia 



II. Zoophyta. 



Cl. 3. Polypi. Ord. Anthozoa and Bryozoa. 

Cl. 4. Acalephae. Ord. Siphonophora, Discophora, Ctenophora. 

Cl. 5. Echinodermata. 



Ord. Crinoidea, Asteroidea, Echinoidea, Holothurioidea, and 



Sipunculoidea. 



III. Vermes. 



Cl. 6 



\ 



Helminthes. Ord. Cystici, Ces- f Since the Publication of the work quoted above, Sie- 

todes, Trematodes, Acanthocephali, J b ° ld has introduced most im P ortan t improvements in the 

classification of the Worms, and ereatlv increased our 



Gordiacei, Nematodes. 



I knowledge of these animals. 



Cl. 7. Turbellarii. Ord. Rhabdocoeli, Dendrocoeli. 
Cl. 8. Rotatorii. Not subdivided into orders. 
Cl. 9. Annulati. Ord. Apodes and Chastopodes. 



IV. Mollusca. 



Cl. 10. Acephala. Ord. Tunicata, Brachiopoda, Lamellibranchia. 

Cl. 11. Cephalophora, Meek., (Gasteropoda.) Ord. Pteropoda, Heteropoda, Gasteropoda, 

Cl. 12. Cephalopoda. Not subdivided into orders. 



V. Arthropoda. 



- 



Cl. 13. Crustacea. Ord. Cirripedia, Siphonostoma, Lophyropoda, Phyllopoda, Poecilopoda, 

Lsemodipoda, Isopoda, Amphipoda, Stomapoda, Decapoda, Myriapoda. 

Cl. 14. A r a c h n i d a . Orders without names. 

Cl. 15. Insecta. a. Ametabola. Ord. Aptera. b. Hemimetabola; Ord. He- 

miptera, Orthoptera. c. Holometabola. Ord. Diptera, Lepidoptera, Hymenop- 
tera, Strepsiptera, Nevroptera, and Coleoptera. 



VERTEBRATA 



VI. Vertebrata. 



Cl. 16. Pisces. Subclasses: 1st. Leptocardii. 2d. Marsipobranchii. 3d. 

Elasmobranchii; Ord. Holocephali, Plagiostomi. 4th. Ganoidei; Ord. 

■ 

Chrondrostei, Holostei. 5th. T e 1 e o s t e i ; Ord. Acanthopteri, Anacanthini, Pharyn- 



Plectosrnathi 



6th. Dipnoi. 



Cl. 17. Reptilia. Subclasses: 1st. Dipnoa; Ord. Urodela, Batrachia, Gymnophiona. 



2d. Monopnoa: 
Chelonia, Crocodila. 



Cl. 18. Aves. 



Cl. 19. M 



a. Streptostylica ; Ord. Ophidia, Sauria. b. Monimostylica ; Ord. 

The subdivisions of the classes Pisces and Reptilia are taken from the sec- 
ond edition, published in 1854-1856, in which J. Muller's arrangement of the 
Fishes is adopted; that of the Reptiles is partly Stannius's own. The 
classes Aves and Mammalia, and the first volume of the second edition, are 
not yet out. 















































i 






Chap. III. 



ANATOMICAL SYSTEMS. 



209 



The most original feature of the classification of von Siebold is the adoptior 
of the types Protozoa and Vermes, in the sense in which they are limited here 



The type of "Worms has g 



out of the investigations of the helmintholog 



who, too exclusively engaged with the parasitic Worms, have overlooked their rela- 



tions to the other Articulata. On the other hand, the 



which most ento- 



mologists have remained from the zoologists in general, has no doubt had its share in 
preventing an earlier thorough comparison of the Worms and the larval conditions of 

Insects, without which the identity of type of the Worms, Crustacea, and Insects 

can hardly be correctly appreciated. Concerning the classes 1 adopted by von Sie- 
bold and Stannius, I have nothing to remark that has not been said already. 



CLASSIFICATION OF R. LEUCKART. 



Mor 



The classification of Leuckart is compiled from the following work : Leuckart, (R.,) Ueber die 
phologie und die Verwandtschaftsverhaltnisse der wirbellosen Thiere, Braunschweig, 1848, 1 vol. 8vo. 

■ 

I. COELENTERATA, Lkt. 

Cl. 1. Polypi. Ord. Anthozoa and Cylicozoa (Lucernaria.) 
Cl. 2. A c a 1 e p h a e . Ord. Discophorae and Ctenophorae. 

II. ECHINODERMATA, Lkt. 

Cl. 3. P e 1 m a t o z o a , Lkt, Ord. Cystidea and Crinoidea. 

Cl. 4. Actinozoa, Latr. Ord. Echinida and Asterida. 

Cl. 5. Scytodermata, Brmst. Ord. Holothuriae and Sipunculida. 

- 

III. Vermes. 

Cl. 6. A n e n t e r a t i , Lkt. Ord. Cestodes and Acanthocephali. (Helminthes, Burnt.) 

Cl. 7. Apodes, Lkt. Ord. Nemertini, Turbellarii, Trematodes, and Hirudinei. (Trematodes, Burm.) 

Cl. 8. Ciliati, Lkt. Ord. Bryozoa and Rotiferi. 

Cl. 9. A n n e 1 i d e s . Ord. Nematodes, Lumbricini, and Branchiati. (Annulati, Burm., excl. Ne- 

mertinis et Hirudineis.) 

i 

IV. Arthropod a. 

Cl. 10. Crustacea. Ord. Entomostraca (Neusticopoda Car.) and Malacostraca. 



Cl. 11. Insecta. Ord. Myriapoda, Arachnida, (Acera, Latr.,) and Hexapoda. 



V. Mo 



Cl. 1 2. T u n i c a t a . 



jN^itzsch.) 

1 Leuckart is somewhat inclined to consider the Tunicata 

Ord. Ascidise (Tethyes I 



Sav.) and Salpse (Thalides Sav.) 



not simply as a class, but even as another great type or branch 
J intermediate between Echinoderms and Worms. 



Cl. 13. Acephala. Ord. Lamellibranchiata (Cormopoda Nitzsch, Pelecypoda Car.) and Bra- 

chiopoda. 
Cl. 14. Gasteropoda. Ord. Heterobranchia, (Pteropoda, Inferobranchia, and Tectibranchia,) 

Dermatobranchia, ( Gy mnobranchia and Phlebenterata,) Heteropoda, Ctenobranchia, Pulmo- 
nata, and Cyclobranchia. 

Cl. 15. Cephalopoda. 
VI. Vertebrata. (Not considered.) 












1 1 















■ I 






■ 








































































1 The names of the types, Protozoa and Vermes, are older 
than their limitation in the classification of Siebold. That of 
Protozoa, first introduced by Goldfuss, has been used in vari- dom, but in a totally different sense. 

27 



Worms 



adopted by Linnaeus, as a great division of the animal king- 

•m 1 « . 11 -I • /M 



















I 
































X. 















I, 


















III 



III 





















































-v 



210 



ESSAY ON CLASSIFICATION. 



Part I. 



I need not repeat here what I have already stated, in the first section, respecting 
the primary divisions adopted by Siebold and Leuckart. As to the classes, I may 



add that his three classes of Echinoderms exhib 



only ordinal characters. Besides 



Birds and Cephalopods, there is not another class so well defined, and 



so 



little 



ptible of being subdivided into minor divis 



characters, as that of Echinoderms 



ons p 
Their systems of 



'g 



' any thing like class 
are so closely homo- 



g 



compare p. 183,) that the attempt here made by Leuckart, of subdividing 



of 



them into three classes, can readily be shown to rest only upon the admission 
classes, of groups which exhibit only ordinal characters, namely, different degrees 
complication of structure. With reference to the classes of Worms, the same is 
equally true, as shown above. The arrangement of these animals proposed by Bur- 
meister is certainly more correct than those of von Siebold and of Leuckart, inas- 
much as he refers already correctly the Rotifera to the class of Crustacea, and does 
not, like Leuckart, associate the Bryozoa with the Worms. 
Leuckart respecting the propriety of 



I agree, however, 



among the true Annelides. 



with 
the Nemertini and Hirudinei from 

- 

Again, Burmeister appreciates also more correctly the 



removing 



position of the whole type of Worms, in 
branch of Articulata. 



referring them, with 



de Blainville, to the 



The 
since C 



common fault of all the anatomical classifications which have been proposed 



mental idea of the 




first, in having g 
an of structure. 



ti up, to a greater or less extent, 

beautifully brought forward by C 



the funda 



and 



upon which he has insisted with increased confidence and more and more distinct 



sciousness, ever since 1812; and, second, in having allowed that of complication of 



structure frequently to take the preced 



which, to be 



ctly appreciated, require 



over the more general features of plan, 
, is true, a deeper insight into the struc- 



ture of the whole animal kingdom than is needed merely for the investigation of 
anatomical characters in single types. 

Yet, if we take a retrospective glance at these systems, and especially con- 
sider the most recent ones, it must be apparent to those who are conversant with 



the views now obtaining in our 



that, after a test of half 



idea of the existence of branches, characterized by different 




a century, the 
of structure, as 



expressing the true relations 



g animals, has prevailed over the idea of a 



gradated scale including all animals in one progressive series. When it is con- 
sidered that this has taken place amidst the most conflicting views respecting classi- 
fication, and even in the absence of any ruling principle, it must be acknowl- 



edged that this can 
pounded by Cuvier. 



be only owing to the 
We recognize in the 



internal truth of the views first pro- 

classifications of Siebold, Leuckart, and 

conception of the French naturalist, even though 



others the triumph of the great 

their systems differ greatly from his, for the question whether there are four or 
































I 







J 









Chap. III. 



PHYSIOPHILOSOPHICAL SYSTEMS 



211 



more g 



pla 



limited in this or any other way, is not a questi 



ciple, but one involving only accuracy and penetration in the 
I maintain that the first sketch of Cuvier, with all its imperfect 



>n of prin- 
sstigation ; and 
of details, pre- 



sents a picture of the essential relations existing 

than the seemingly more correct classifications of recent writers 



& among animals truer to nature 



SECTION V. 



PHYSIOPHILOSOPHICAL SYSTEMS. 



About the time that Cuvier and the French naturalists were tracing the structure 
of the animal kingdom, and attempting to erect a natural system of Zoology upon 
this foundation, there arose in Germany a school of philosophy, under the lead 
of Schelling, which extended its powerful influence to all the departments of physical 



science. 



Oken, Kieser, Bojanus, Spix, Huschke, and Cams are the most eminent 



naturalists who applied the new philosophy to the study of Zoology. 



But 



no 



one 



to speak 



is moreover 



easier, while borrowing his ideas, to sneer at his style and his 



■© 



nomenclature, than to discover the true meaning 






identified his philosophical views so completely with his studies in natural 

history as Oken. 

Now that the current is setting so strongly against every thing which recalls 
the German physiophilosophers and their doings, and it has become fashionable 

■ 

ill of them, it is an imperative duty for the impartial reviewer of the 
history of science to show how great and how beneficial the influence of Oken 
has been upon the progress of science in general and of Zoology in particular. 

It 

of what is left unexplained in 

his mostly paradoxical, sententious, or aphoristical expressions; but the man who 
has changed the whole method of illustrating comparative Osteology, — who has 
carefully investigated the embryology of the higher animals, at a time when few 
physiologists were paying any attention to the subject, who has classified the three 
kingdoms of nature upon principles wholly his own, who has perceived thousands 
of homologies and analogies among organized beings entirely overlooked before, who 
has published an extensive treatise of natural history containing a condensed account 
of all that was known at the time of its publication, who has conducted for twenty- 
five years the most extensive and most complete periodical review of the natural 
sciences ever published, in which every discovery made during a quarter of a 
century is faithfully recorded, the man who inspired every student with an ardent 
love for science, and with admiration for his teacher, 



that 



man will never be 



forgotten, nor can the services he has rendered to science be overlooked, 
as thinking is connected with investigation. 



so long 






i 












I 



































































*£m*W 







iri 



i 



















212 



ESSAY ON CLASSIFICATION. 



Part I 


































CLASSIFICATION OF OKEN. 



The following diagram of Oken's classification is compiled from his Allgemeine Naturgeschichte fur alle 
Stiinde, Stuttgardt, 1833-1842, 14 vols. 8vo. ; vol. 1, p. 5. The changes this system has undergone may 
be ascertained by comparing his Lehrbuch der Naturphilosophie, Iena, 1809-1811, 3 vols. 8vo. ; 2d edit., 
Iena, 1831; 3d edit., Zurich, 1843; Engl. Ray Society, London, 1847, 1 vol. 8vo. — Lehrbuch der Natur- 
geschichte, Leipzig, 1813; Weimar, 1815 and 1825, 8vo. — Handbuch der Naturgeschichte zum Gebrauch 
bei Vorlesungen, Niirnberg, 1816-1820, 8vo. — Naturgeschichte fur Schulen, Leipzig, 1820, 1 vol. 8vo., 
and various papers in the Isis. 



■ 

1st Grade. Intestinal Animals ; also called iWy-animals and TWcA-animals. Only one cavity ; no head 

with a brain, only the lowest sense perfect, intestines and skin organs, but no flesh, that is 
no bones, muscles, or nervous marrow -==• Invertebrata. 
Characterized by the development of the vegetative systems of organs, which are those of digestion, circula- 

tion, and respiration. Hence 









Cycle I. Digestive Animals. = Radiata. Essential character : no development beyond an intestine. 

Cl. 1. Infusoria, (Stomach animals.) Mouth with cilia only, to vibrate. 
Cl. 2. Polypi, (Intestine animals.) Mouth with lips and tentacles, to seize. 
Cl. 3. Acalephae, (Lacteal animals.) Body traversed by tubes similar to the lymphatic vessels 



Cycle II. Girculative Animals. = Mollusks. Essential character : intestine and vessels. 

Cl. 4. Acephala, (Biauriculate animals.) Membranous heart with two auricles. 
Cl. 5. Gasteropoda, (Uniauriculate animals.) Membranous heart with one am 

■ 

Cl. 6. Cephalopoda, (Bicardial animals.) Two hearts. 



■ 

Cycle III. JRespirative Animals. = Articulata. Essential character : intestine, vessels, and spiracles, 

* 

Cl. 7. Worms, (Skin animals.) Respire with the skin itself, or part of it, no articulated feet 
Cl. 8. Crustacea, (Branchial animals.) Gills or air tubes arising from the horny skin. 
Cl. 9. Insects, (Tracheal animals.) Tracheae internally, gills externally as wings. 












- i 

2d Grade. Flesh Animals; also called i&ae?-animals. = Vertebrata. Two cavities of the body, surrounded 

by fleshy walls, (bones and muscles,) inclosing nervous marrow and intestines. Head with 
brain ; higher senses developed. Characterized by the development of the animal systems, 
namely, the skeleton, the muscles, the nerves, and the senses. 

» r 

Cycle IV. Carnal Animals proper. Senses not perfected. 

L 

- 1 

Cl. 10. Fishes, (i?<me-animals.) Skeleton predominating, very much broken up ; muscles white, 

brain without gyri, tongue without bone, nose not perforated, ear concealed, eyes without 



lids. 



Cl. 11 



(Muscle 



Muscles 



nose perforated, 



ear without external orifice, eyes immovable with imperfect lids. 






Cl. 12. Birds, (iVerre-animals.) Brain with convolutions, ears open, eyes immovable, lids 

imperfect. \ ' 

■ 

* 

Cycle V. Sensual Animals. All anatomical systems, and the senses perfected. 

i 

Tongue and nose fleshy, ears open, mostly with a conch, 



Cl. 13. M 



eyes movable, with two distinct lids. 









. 




























s 






Chap. III. 



PHYSIOPHILOSOPHICAL SYSTEMS. 



213 



w 



The principles laid down by Oken, of which this classification is the practical 
result for Zoology, may be summed up in the following manner: The grades or 




reat typ 



of Animals are determined by their anatomical 



ems, such as the 



body and head 



m 



the animal kingdom 



or the intestines, and the flesh and senses. Hence two grades 

Animals are, as it were, the dismembered body of man 



made alive 



The classes of animals are the special representation in 



g 



forms 



of the anatomical systems of the highest being in creation. 



Man is considered, in 



th 



ystem, not 




as 



the key of the whole 



kingdom, but also as the standard measure of the organization of animals 



mimal 
There 



exists nothing in the animal kingdom 



hich 



not 



presented in higher combina 



Man. The existence of several distinct pla 



of 



among: animals 



& 



lly denied. They are all built after the patte 



of Man; the differences 



among them consist only 



their exhibiting either one system only, or a larg 



or smaller number of systems of org 



of higher or lower physiological impor 



developed either singly 



connection with one another 



their body 



The principles of classification of both Cuvier 

negatived. The principle of Cuvier, who admits four different 

the animal kingdom, is, indeed, incompatible with the idea that all animals 



and Ehrenberg are here entirely 

ans of structure 




m 



•& 



present 




the 



g 



of Man. The principle of Ehrenberg, who considers 



all animals as equally perfect 
that all animals represent an 



as completely irreconcilable with the assumpt 



qual 



sum 



of 



gans; for, according to Oken, the 



body of animals 



as 



it were, the analyzed body of Man, the organs of which 




or in various 



live sino 

bination constitutes a distinct class 



combinations as independe 



animals. Each such com 



The principle upon which the orders are 



founded has already been explained above, (Chap. II, Sect. III., p 



154 



There is something very taking in 



the idea that Man is the standard of appre 



ciation of all animal structures, 
made to apply 



But all the attempts which have thus far been 

be considered as com- 



to the animal kingdom as it exists, must 



plet 



fail 



In his different works, Oken has 



ely identified the systems 



of organs of Man with different groups 
have adopted the same 



of animals, and different authors, who 



ent ways 



The 



principle of classification, have identified them in still differ- 
practicability of such a scheme must be obvious to any one 

ins of structure 



who has satisfied himself practically of the existence of different 




in 



the 



g 



of 



mals. Yet, the unsoundness of the general principl 



the classifications of the physiophilosoph 



i of 
should not render us blind to all that 



is valuable in their special writing 



The works of Oken in particular teem with 



iginal suggestioi 
quaintance with 



pecting the n 



atural affinities of animals 



and his thorough 



7 



g 



■ 

of his predecessors and contemp 



shows 



him to have been one 



of the most learned 



g 



of this 



ntury 



\ 



. I 



( 



1 



< ■ 



• 



• ! 















i 



















































\ 

















^^^M^ 





































































I 



214 



ESSAY ON CLASSIFICATION 



Part I. 



CLASSIFICATION OF FITZINGER 





































This diagram is extracted from Fitzinger's Systema Reptilium, Vindobonae, 1843, 1 vol. 8vo 



I. Provincia. Evertebrata. 

i 

Animalia systematum anatomicorum vegetativorum gradum evolutionis exhibentia. 






A. Gradus evolutionis systematum physiologicorum vegetativorum. 



B 



I. Circulus. Gastrozoa. 

Evolutio systematis nutritionis 



a. Evolutio praevalens 

systematis digestionis 
Cl. 1. Inf u soria. 



b. Evolutio prgevalens 

systematis circulationis 



. 






Cl. 2. Zoophyta. 



II. Circulus. Physiozoa. 

Evolutio systematis generationis. 
Cl. 4. Vermes. 



Cl. 5. Radiata. 



* 

Gradus evolutionis systematum physiologicorum animalium 



c. Evolutio praavalens 

systematis respirationis 

Cl. 3. Acalephae. 



Cl. 6. Ann u lata 






III. Circulus. Dermatozoa. 

Evolutio systematis sensibilitatis 
Cl. 7. Acephala. 



Cl. 8. Cephalopoda 



Cl. 9. M o 1 1 u s c a 






IV. Circulus. Arthrozoa. 

Evolutio systematis motus 
Cl. 10. Crustacea. 



Cl. 11. Arachnoidea 



Cl. 12. Insecta 










II. Provincia. Vertebrata. 



Animalia systematum anatomicorum animalium gradum evolutionis exhibentia 



A 



Gradus evolutionis systematum physiologicorum vegetativorum. 



Cl. 13. Pisces. 



B 



■ 

a. Evolutio systematis nutritionis, simulque ossium : . .' 

h. Evolutio systematis generationis, simulque musculorum: Cl. 14. Rep til ia 

* 

Gradus evolutionis systematum physiologicorum animalium. 

e. Evolutio systematis sensibilitatis, simulque nervorum: Cl. 15. Aves. 
d. Evolutio systematis motus, simulque sensuum: . . . 



Cl. 16. Mammalia 



The fundamental idea of the classification of Fitzinger is the same 



as 



that 



upon which Oken has based his system. The higher divisions, called by him 
provinces, grades, and cycles, as well as the classes and orders, are considered as 

% 

representing either some combination of different systems of 
ticular system of organs, or some special organ. His two 
are the Evertebrata and Vertebrata. The Evertebrata 



gans, or some par 



highest groups (provinces) 
represent the systems of 












the 



g 



'g 



and the Vertebrata those of the animal 



'g 



as the Gut 






■ i 















■ ■ 












t 



Chap. III. 



PHYSIOPHILOSOPHICAL SYSTEMS. 



215 



* 

animals and the Flesh-animals of Oken. Instead, however, of adopting, like Oken 



mical names for his divisions, Fitzinger employs those most generally 



use. 



or grades of these two primary groups are based upon a repetition 



His subdivisions 

of the same differences, within their respective limits 



the 



g 



g 



prevail 



contrasted with those 



The Invertebrata, in 
in which the animal 



which 



g 



drawn among the 



Vertebrata 



Each of 



prevail, and the same distinction is ag 

these embraces two circles founded upon the development of one particular system 

of organs, etc. 

should present a closer agreement with one 

upon anatomical differences 

if its advocates cannot even ag 



It cannot be expected that the systems founded upon such principles 

another than those which are based 

■ 

yet I would ask, what becomes of the principle itself, 

their 



upon what anatomical systems 



of organs 



classes are founded 



According to Oken, the Mollusks (Acephala, Gasteropoda, and 



Cephalopoda) represent the system of circulat 



at least in the last edition of 



that 



his system he views them in 

senting the system of sensibility 

and Insects) with the system of respiration, Fitzing 



the 



pti 



of the Worms, including Radiata 



ght, whilst Fitzinger considers them as repre- 
Oken identifies the Articulata (Worms, Crustacea, 

with that of motion, with 

zes with the 



/ 



vstem of reproduct 



etc. 



Such discrep 



which he parallelizes 
must shake all confidence in 



these systems, though they should not prevent us from 



g the happy com 



parisons and sugg 



to which the various attempts to classify the animal king 



dom in this way have led their authors 



It is almost superfluous to add, that 



g 



as the disagreement 



between the system; 



of diffe 



physiophilosopher 



we find quite as striking discrep 
of the same author. 



between the different editions of the system 



- 

The principle of the subdivision of the classes among Invertebrata is here exemplified from the Radiata, 



(Echinodermata.) 



1st Series. 
Evolutio praevalens 



Each series contains three orders. 
2d Series. 



- 

systematis digestionis. 
Asteroidea. 
1. Encrinoidea. 2. Comatulina 

3. Asterina. 



Evolutio praevalens 
systematis circulationis 
Echinodea. 



1. Aprocta 



2. Echinina 



3. Spatangoidea. 



3d Series. 
Evolutio praevalens 

systematis respirationis. 
Scytodermata (Holothurioids.) 

* 

1. Synaptoidea. 2. Holothurioidea. 

3. Pentactoidea. 






In Vertebrata, each class has five series and each series three orders ; so in Mammalia, for example 



1st Series. 



2d Series. 



3d Series. 



4th Series. 



5th Series. 



Evolutio praevalens Evolutio praevalens Evolutio praevalens 



Evolutio praevalens Evolutio praevalens 



sensus tactus. 
C e t a c e a . 

1. Balarrodea. 

2. Delphinodea 

3. Sirenia. 



sensus gustus. 
Pachydermata 

1. Phocina. 

2. Obesa. 

3. Ruminantia. 



sensus olfactus. 
Edentata. 

1. Monotremata 

2. Lipodonta. 

3. Tardigrada. 



sensus auditus. 
Unguiculata 
L Glires. 

2. Bruta* 

3. Ferae. 



sensus visus. 

Primate s. 

1. Chiropteri. 

2. Hemipitheci. 

3. Anthropomorphi 









! 






























■ 


















1 
























I 






















i 
























































• 




















1 






























, 


































I 




















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! 

































































































216 



S 



ON 



SS 



Part I 



Instead of considering the orders as founded 



upon a repetition of the characters 

as founded upon 



it, Fitzinger adopts series 



of higher groups, as Oken would have 

that idea, and subdivides them further into orders, as above. These series, however, 



have still less reference to the systems of org 



which they 



than either the classes or the higher divisions of the animal kingdom 



said to represent, 

In these 



attempts to arrange minor group 



of animals into natural series, no one can 



fail 



to perceive an effort to adapt the frames of our systems to the impression we 
receive from a careful examination of the natural relations of organized beings. 



Everywhere we 



such 



sometimes extending only over groups of species 



at other times embracing many genera, entire families, nay, extending frequently to 
several families. Even the classes of the same branch may exhibit more or less 
distinctly such a serial | 



radat 



But I have failed, thus far, to discover the 



upon 



principle to which such relations may be referred, as far as they do not rest 
complication of structure, 1 or upon the degree of superiority or inferiority of the 
features upon which the different kinds of groups are themselves founded. Analogy 



of analo 



gy 



have b 



plays also into the series, but before the categories 

carefully scrutinized as those of affinity, it is impossible to say within what limits 

this takes place. 



CLASSIFICATION OF McLEAT. 


















* 











The great merit of the system of McLeay, 2 and in my opinion it has no other 
claim to our consideration, consists in having called prominently the attention of 
naturalists to the difference between two kinds of relationship, almost universally 

■ 

lity and analogy. Analogy is shown to consist in the repeti- 



founded before 




tion of similar features in groups otherwise remote, as far as their anatomical 

■ 

characters are concerned, whilst affinity is based upon similarity in the structural 
relations. On account of the similarity of their locomotion, Bats, for instance, may 



be considered as 



g 



to Birds; Whales are analog 



to Fishes on account 



of the similarity of their form and their aquatic mode of life; whilst both Bats 
and Whales are allied to one another and to other Mammalia on account of the 
identity of the most characteristic features of their structure. This important dis- 

interesting results. Thus far, however, it has only 



tinction cannot fail to lead to 



produced fanciful comparisons from those who first traced it out. It is assumed, 
for instance, by McLeay, that all animals of one group must be analogous to 



• • 



1 Compare Chap. II., Sect. 3, p. 153. 



those of the German physiophilosophers, but on 



2 I have introduced the classification of McLeay account of its general character, and because it is 
in this section, not because of any resemblance to based upon an ideal view of the affinities of animals. 































■ ■ 



- ■ ^n 



§■ 























' 









/ 









Chap. III. 



PHYSIOPHILOSOPHICAL SYSTEMS. 



217 



in 



order 



a manner 



those of every other group, besides forming a circle in themselves; and 

to carry out this idea, all animals are arranged in circular groups, in such 

as to bring out these analogies, whilst the most obvious affinities are set aside to 

■ 

favor a preconceived view. But that I may not appear to underrate the merits 



of this system, I will present it in the 



■y words of its most zealous admir 



and self-complacent expounder, the learned William Swainson. 



i 



The Horae Entomolog 



2 



unluckily for students 



can 




be thoroughly 



understood by the adept, since the results and observations are explained in different 
s; the style is somewhat desultory, and the groups, for the most part, are rather 



parts ; 

indicated than defined 



The whole, in short, is what it professes to be, more 



a 



rough sketch of the leading peculiarities of the great divisions of animals, and the 
manner in which they are probably connected, than an accurate determination of 
the groups themselves, or a demonstration of their real affinities. More than this, 

* 

perhaps, could not have been expected, considering the then state of science, and 



the herculean difficulties which the author had to surmount 



The work in ques 



tion has now become exceedingly scarce, and this will be an additional reason 



with 



for communicating 



from it to the reader 



theory will be best understood by 



Mr. McLeay 



g his diagram; for he has not, 



as we 



have 



Iready remarked, defined any of the vertebrated groups. Condensing, how 



ever, the result of his remarks, we shall 



them as resolvable into the followin 



propositio 



1. That the natural series of animals is 






were, a circle, so that, upon commencin 



at 



any one g 



g all the modifications of 



g 



itinuous, forming, as it 

ven point, and thence 

shall be imperceptibly led, after passing 

to the point from which we started; 2. That no 



we 



through numerous forms, j 
groups are natural which do not exhibit such a circular series; 3. That the 
primary divisions of every large group are ten, five of which are composed of 
comparatively large circles, and five of smaller: these latter being termed osculant, 
and being intermediate between the former, which they serve to connect; 4. That 
there is a tendency in such groups as are placed at the opposite points of a 



circle of affinity 



meet each other 



5 



That 



one 



of the five larger groups 



into which every natural circle is divided, < bears a resemblance to all the rest, 



or 



more 
other 



tly speaking, consists of types which 



repr 



those of each of the four 



groups 



gether with a 



typ 



peculiar to itself.' These are the chief and 



leading principles which Mr. McLeay considers as belonging to the natural system 
We shall now copy his diagram, or table of the animal kingdom, and then endeavor 

i 

with this help, to explain the system more in detail." 



i 



Swainson, (W.,) A Treatise of the Geography 



McLeay, (W 



HoraB Entomologies, 



or 



and Classification of Animals, London, 1835, 1 vol. Essays on the Annulose Animals, London 1819-21 



12mo., p. 201-205. 



2 vols. 8vo. 



28 











































































• 













1 












\ 




T^ 







218 



ESSAY ON CLASSIFICATION 



Part I 










2. 

5" 

c 



CD 

<! 

CD 
CD 



CD 
P 

(73 



§■ 



CD 

5 

as 

p.. 
o 



o 

2. 
n" 

CD 



P. Rudes. 

P. Vaginati. 

AC RITA, 



Agastria. 



MOLLUSCA. 



Acephala. 



Pteropoda 



Brachiopoda. 



Reptilia. 



Aves. 



VERTEBRATA. 



Mammalia 



P. Natantes 



Amphibia. 



Intestina. 



AOTMALTA 



Pisces. 



<&>* 



Fistulida. 



Acalephidae. 



RADIATA 



Ametabola. 

Mandibulata. 

ANNULOSA. 



***fc 



Echinidse. k Crustacea. 



Medusidag. 



Haustellata 



Stelleridse. 



Arachnids 



' 









/ 






u 



We must, in the first instance, look to the above tabular disposition of all 



animals, i 
or blends 



forming themselves collectively 



one 



g 



which 



touches 



of 



of this great circular * 
tion, to exhibit five g 



another, composed of plants, by means of the 'least organized beings 

Next we are to look to the larger component parts 

tnce with the third proposi- 



the vegetable kingdom 



mblag 



We find 



accord 



or polyps; Kadiata, or 
brated animals; each passing or blending 
groups of animals, much smaller, indeed, 
connecting or osculant 



circles, composed of the Mollusca, or shellfish; Acrita, 
r-fish; Annulosa, or insects; and Vertebrata, or verte- 



each 
their 



the 



by means of five other 



extent, but forming so many 



circles. 1 The number, therefore, as many 



sly suppose 



is not five, but ten. This is quite obvious 



and 



our opinion on this point is 



confirmed by the author himself, in the following passage, when alluding to his 



remarks upon the whole 



The foreg 



observations, I am well aware, are far 



from accurate, but they are sufficient to prove that there are five 

* 

groups in the animal kingdom, each of which possesses a peculiar stru( 



S 



circular 
and that 






1 In the original diagram, as in that above, these but merely indicated by the names arranged like 
five smaller circles are not represented graphically, rays between the five large circles. 












■V M 



' '• 



' 



. 






^s 



fr^^^^L 




: ; 










' 






/ 









Chap. III. 



PHYSIOPHILOSOPHICAL SYSTEMS. 



219 



these, when connected by means of five smaller osculant groups, compose the 



whole province of Zoolo 



Now these smaller osculant groups are to b 



ed 



as circles, for, as it is elsewhere stated, 'every natural group is a circle, more 
or less complete.' This, in fact, is the third general principle of Mr. McLeay's 



system, and he has exemplified 



his meaning 



of a natural group in the above 



diagram, where all animals are arranged under five large groups or circles, and 



• 

five smaller ones. 



Let us take one of these groups, the Vertebrata: does that 



form a circle of itself? Yes; because it is intimated that the Reptiles {Reptilia) 



pass into the Birds, (A 



these again into the Quadrupeds, (Mammalia,) Quadruped 



unite with the Fishes, {Pisces,) these latter with the amphibious Reptiles, and the 
Frogs bring us back again to the Reptiles, the point from whence we started. 

out and shown to be circular : 



Thus, the series of the 



tebrated group is marked 



therefore, it is a natural group. This is an instance where the circular series 
can be traced. We now turn to one where the series is imperfect, but where 
there is a decided tendency to a circle: this is the Mollusca. Upon this group 



our 



author 



says 



'I have by no means determined the circular disposition to hold 
good among the Mollusca ; still, as it is equally certain that this group of animals 
is as yet the least known, it may be improper, at present, to conclude that it 



forms 



any 



pt 



to the rule ; it would even seem 



questionable that the 



Gasteropoda of C 



r 

return into themselves, so as to form a circular group; b 



whether the Acephala form one or two such, is by 



means accurately ascertained 



though 



enough is known of the Mollusca to incline us to suspect that they are 



no less subjected, in general, to a circular disposition than the four other great 



groups 



This, therefore 



author considers as one 



of those groups which, without 



actually forming a circle, yet evinces a disposition to do so ; and it is therefore 
presumed to be a natural group. But, to illustrate this principle farther, let us 
return to the circle of Vertebrata. This, as we see by the diagram, contains five 
minor groups, or circles, each of which is again resolvable into five others, regu- 



lated precisely 



the 



same way. The class Aves, for example, is first divided 



into rapacious birds, (Eaptores,) perching birds 



gallinaceous birds, (R 



•es,) and swimming birds (Natatores) ; and the proof of this 
group is, in all these divisions blending into each other at 
their confines, and forming a circle. In this manner we proceed, beginning with 



wading birds, (GralMot 
class being a natural 



the higher groups, and descending 



to the lower, until at length we descend to 
genera, properly so called, and reach, at last, the species; every group, whether 



large or small, forming a circle of its 



own. 



Thus there are circles within circles, 
wheels within wheels,' — an infinite number of complicated relations; but all 



regulated by one simple and uniform principle, — that is 



the 



rcularity of 



ery 



group 



5> 

















































-I 



1 



I 



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J 

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I 



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220 



ESSAY ON CLASSIFICATION. 



Part I 




The writer who can see that the Quadrupeds unite with the Fishes, and the 
like, and yet says that Cuvier "was totally unacquainted with the very first princi- 
es of the natural system," hardly deserves to be studied in our days. 

The attempt at representing graphically the complicated relations which exist 
among animals has, however, had one good result; it has checked, more and more, 
the confidence in the uniserial arrangement of animals, and led to the construction 
of many valuable maps exhibiting the multifarious relations which natural groups, 
of any rank, bear to one another. 













SECTION VI 






EMBRYOLOGICAL SYSTEMS. 


















i ■ 



Embryology, in the form it has assumed within the last fifty years, is 



as 



completely a German science as the " Naturphilosophie." It awoke to this new 

■ 
> 

activity contemporaneously with the development of the Philosophy of Nature. It 
would hardly be possible to recognize the leading spirit in this new development, 
from his published works ; but the man whom Pander and K. E. von Baer 
acknowledge as their master must be considered as the soul of this movement, 
and this man is Ignatius Dollinger. It is with deep gratitude I remember, for 
my own part, the influence that learned and benevolent man had upon my studies 
and early scientific application, during the four years I spent in his house, in 
Munich, from 1827 to 1831 ; to him I am indebted for an acquaintance with what 
was then known of the development of animals, prior to the publication of the 



g 



work of B 



and from his lectures I first learned to 



ppreciate the im 






The investigations of Pander 



portance of Embryology to Physiology and Zoology. 

upon the development of the chicken in the egg, which have opened the series 



of those truly 



g 



inal researches in Embrj 



of which Germany may justly 



be proud, were made under the direction and with the cooperation of Dollin 
and were soon followed by the more extensive works of Bathke and Baer, 



6 



whom 



th 



civilized world acknowledges as the founders of modern Embryology 
The principles of classification propounded by K. E. von Baer i 



eem never to 



have been noticed by systematic writers, and yet they not only deserve the most 
careful consideration, but it may fairly be said that no naturalist besides Cuvier 
has exhibited so deep an insight into the true character of a natural system, 



> 









Pander, Beitrage zur Entwickelungsgeschichte des Hiihnchens im Eie, Wurzburg, 1817, 1 vol. fol 









^R 



^■W 



■ 







































Chap. III. 



EMBEYOLOGICAL SYSTEMS 



221 



pported by such an extensive acquaintance with the subj 



as this 



g 



embry 



ologist has in his 



Scholien und Corallarien zu der 



Entwickelungsgeschichte des 



Hiihnchens im 
portions, rather 
this may explai 



Eie 



» i 



These principles are presented in the form of general pro 



than in the shape of a diagram with definite 



ematic names, an 



d 



the 



gleet which it has experienced on the part of those who 



are 



better satisfied with words than with thoughts 



A few ab 



howev 



may show how richly the perusal of his work is likely to reward the reader. 

The results at which K. E. von Baer had arrived by his embryological inves- 
tigations, respecting the fundamental relations 



existing among animals, 



differed con- 



siderably from 



ideas then prevailin 



In order, therefore, to be correctly 



understood, he begins, with his accustomed accuracy and clearness, to present a 
condensed account of those opinions with which he disagreed, in these words: 

existing in the organic world have received so 



Few views of the relations 



much approbation as this: that the higher animal forms, in the several stages of 
the development of the individual, from the beginning of its existence to its 
complete formation, correspond to the permanent forms in the animal series, and 
that the development of the several animals follows the same laws as those of 
the entire animal series; that consequently the more highly organized animal, in 

igh the stages that 



its individual development, passes in all that is essential through 

are permanent below it, so that the periodical differences of the individual may 

be reduced to the differences of the permanent animal forms." 

Next, in order to have some standard of comparison with his embry olooical 
results, he discusses the relative position of the different permanent types of 



ani- 



mals, as follows 



a 



It is especially important that 



we should distinguish between the degree of 



perfect 



in the animal structure and the typ 



of 



"g 



g 



on. The degre 
or less heterog 



of perfection of the animal structure consists in the 

neousness of the elementary parts, and the separate divisions of a complicated 

apparatus, — in I one word,lin| 



tiation. 



The more uniform 



the greater histological and morphological differen 
the whole mass of the body is, the lower the 



degree of perfection ; it is a stage 



higher when nerve and muscle, blood and 



cellular tissue, are sharply distinguished 



In proportion to the differ 



between 



these parts, is the development of the animal life in its different tendencies; or, 
to express it more accurately, the more the animal life is developed in its several 
tendencies, the more heterogeneous are the elementary parts which this life brings 



into action. 



The same is true of the single parts of any apparatus 



That 



"g 



1 



Ueber Entwickelungsgeschichte der Thiere, Baer, Konigsberg, 1828, 4to. — See also Acta Nova 



Beobachtung und Reflexion von Dr. Karl Ernst von 



Acad. Leop. Cassar, vol. 13, and Meckel's Arch., 1826. 












* 



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222 



ESSAY ON CLASSIFICATION. 



Part I 





















ization is higher in which the 
themselves, and each part has 

is more uniform. I 



sep 



parts of an entire system differ more among 
individuality, than that in which the whole 



I call type, the relations of 



g 



elements 



d 



gans, as 



far 



as their position is concerned. This relation of position is the expression of cer- 
tain fundamental connections in the tendency of the individual relations of life ; 

as, for instance, of the receiving and discharging poles of the body. The type 



is altogether distinct fro 



the de 



© 



of perfect 



include many 



so that the same typ 



deg 



of perfection 



and 



vice versa, the same 



deg 



tion may be reached in several typ 



i may 

of perfec- 



The degree of perfection, combined with 



the typ 



fi 



determines those 



g 



animal groups which have b 



ailed classes. 



i 



The confounding of the degree of perfection with the type of organization seems 



the cause of much mistaken classification, and in the evident distinction between 
these two relations we have sufficient proof that the different animal forms do 
not present one uniserial development, from the Monad up to Man." 



The types he has re< 

I. The Peripheric Typ< 

centre and the periphery 



gnized 



are : 



The essential contrasts in this type are between the 



2 



The organic functions of life 



are carried on in 



onistic relations from the centre to the circumference 



g 



whole 



Corresponding to this, the 



g 



radiates around a common centre. There exists beside 



the contrast between above and below, but in a weaker de 



only 



\-r 



* 

that between 



ght and left, or before and behind, is not at all noticeable, and the motion 



is 



therefore undetermined in its direction. As the whole 



g 



radiates from 



one focus, so are the centres of all the organic systems arranged, ring-like, around 



& 



o 



& 



it, as, for instance, the stomach, the 



nerves and vessels, (if these parts are devel 



ped,) and the branches extending from them into the 



rays 



What 



we find in 



one 



ay 



is 



peated in every 



■ 

other, the radiation being; 



outwards, and every ray 



always from the centre 



bearing 



the same relation to it. 



II 



The Longitudinal Type, as observed in the Vib 



the Filaria, the Gordius 



the Nais, and throughout the whole series of articulated animals. The contrast 
between the receiving and the discharging organs, which are placed at the two 
ends of the body, controls the whole organization. The mouth and the anus are 



. 



From this statement it is plain that Baer of structure a 



s 



determining the relative rank of 



has a very definite idea of the plan of structure, and the orders, and the different ways in which, and the 

that he has reached it by a very different road from different means with which the plans are executed, 

that of Cuvier. It is clear, also, that he understands I 

the distinction between a plan and its execution. 

But his ideas respecting the different features of 

structure are not quite so precise. He does not 

distinguish, for instance, between the complication his own words. 



as characteristic of the classes. 

2 Without translating verbatim the descriptions 
Baer gives of his types, which are greatly abridged 
here, they are reproduced as nearly as possible in 




























Js 




^^■BBR 



^^^^ 











Chap. III. 



EMBRYOLOGICAL SYSTEMS. 



223 



rually also the sexual organs, 



though their 



opening 



always at opposite ends, and u 

is sometimes farther forward; this occurs, however, more frequently in the females, 

in which these organs have a double function, than in the males. When both 

sexual organs are removed from the posterior extremity, the opening in the female 
usually lies farther forward than in the male. So is it in the Myriapods and 
the Crabs. The Leeches and Earthworms present a rare 



pt 



The 



recep 



g 



of senses, as instrumental to the 

■ee of perfection. 



reach an important deg 



tive pole being thus definitely fixed, the 

receptivity of the nervous system, early 

The intestinal canal, as well as the vascular stems and the nervous system, extend 

through the whole length of the body, and all 



organic motion in these animals 



has the same prevail 



direction. Only subordinate branches of these org 



arise laterally, and chiefly wherever the general contrast, manifested in the whole 



length 



peated 



such a 



manner that, for each separate 



& 



ment. the same 



contrast arises anew, in connection with the essential elements of the whole 



ism. 



organ- 

Hence the tendency in these animals to divide into many segments in the 

In the true Insects, undergoing 



direction of the longitudinal axis of the body. 



metamorphosis 



these segments unite 



gain into three principal 



gions, m 



the first 



of which the life of the nerves prevails; in the second, motion; in the third, 
digestion ; though neither of the three regions is wholly deprived of any one 
of these functions. Besides the opposition between before and behind, a less 
marked contrast is observed in a higher stage of development between above and 



below. 



A difference between right and left forms a rare exception, and is 



gen- 



ally wanting 



Sensibility and irritability are particularly developed in this series. 
Motion is active, and directed more decidedly forward, in proportion as the Ion- 
gitudinal axis prevails. When the body is contracted as in spiders and crabs, 
its direction is less decided. The plastic organs are little developed ; glands, espe- 
cially, are rare, and mostly replaced by simple tubes. 

III. The Massive Type. We may thus call the type of Mollusks, for neither 
length nor surface prevails in them, but the whole body and its separate parts are 
formed rather in round masses which may be either hollow or solid. As the chief 
contrast of their structure is not between the opposite ends of the body, nor between 
the centre and periphery, there is almost throughout this type an absence of 



sym- 



metry. 



Generally the discharging pole is to the 



right 



of the receptive one. 



The discharging pole, however, is either near the receptive one, or removed from 
it, and approximated to the posterior extremity of the body. As the tract of 

■ 

the digestive apparatus is always determined by these two poles, it is more or 



less arched 



m 



its 



simplest form it is only a single arch, as in Plumatella 



When that canal is long, it is curled up in a spiral in the centre, and the spiral 
probably has its definite laws. For instance, the anterior part of the alimentary 



canal appears to be 



Iway 



placed under the posteri 



The principal currents 
















I 









i 






























-' 






224 



ESSAY ON CLASSIFICATION 



Part L 








of blood are also in arches, which do not coincide with the medial line of the 



body. 

larger 

of sense 

IV. 



The 



nervous system consists of diffused g 



b 



united by threads, the 



ones being around the oesophagus 



The 



nervous system and the organs 



appear late ; the motions are slow and powerless 



The Verteh 



Typ 



This 



is 



as it were 



posed of the precedin 



types, as we distinguish an animal and a vegetative system of the body, which, 
though influencing one another in their development, have singly a peculiar typical 



organ 

type, 

There is, howe\ 



In the animal system, the articulation reminds us of the second 



and the discharg 



and 



marked diffe 



for the animal system of the Verteb 



g organs are also placed at opposite ends 

Articulates and the Vertebrates 

along the two sides. 



between 



is not only doubled 



but at the same time upwards and downwards 



walls 



hich unite below circumscribe the 



g 



such a way that the two lateral 

b system, while the two tending 

pward surround a central organ of the animal life, the brain and spinal marrow, 

jsents this type most com- 



which is wanting in Invertebrates 



The solid frame 



repr 



pletely, as from its medial axis, the backbone, there arise upward arches which close 
in an upper crest, and downward arches which unite, more or less 
Corresponding to 



this 



we 



four rows of 



in a lower crest, 
threads along the spinal marrow, 
which itself contains four strings, and a quadripartite grey mass. The muscles 
of the trunk form also four principal masses, which are particularly distinct in the 



Fishes 



The animal system is therefore doubly symmetrical 



gement 



It 



might easily 



be shown how the vegetative systems of the 



body 



ipond to the 



typ 



e of Mollusks, though influenced by the animal system 

From the illustrations accompanying this 



discussion of the 



g 



types or branches 



of the animal kingdom, and still more from the paper published by K. E. von 
Baer in the Nova Acta, 1 it is evident, that he perceived more clearly and earlier 
than any other naturalist, the true relations of the lowest animals to their respective 
branches. He includes neither Bryozoa nor Intestinal Worms among Radiata, as 



Cuvier, and after him so many modern writers, did, but 
to the Mollusks and the latter to the Articulates. 



ctly refers the former 



Comparing these four types with the embry 



development, von Baer shows 



that there 



nly a general similarity between the lower 



and the embry 



stages of the higher ones, arising mainly from the absence of differentiation in the 



body, and not from a typical resemblance. The embryo does not 



P 



from one 



typ 



to the other; on the contrary, the type of each animal is defined from the 














1 Beitrage zur Kenntniss der niedern Thiere, animals. These " Beitrage," and the papers in which 

■ 

Nova Acta Academic Naturae Curiosorum, vol. 13, Cuvier characterized for the first time the four great 

Part 2, 1827, containing seven papers, upon Aspido- types of the animal kingdom, are among the most 

gaster, Distoma, and others, Cercaria, Nitzschia, Poly- important contributions to general Zoology ever 

stoma, Planaria, and the general affinities of all published. 






■ 




■ 



^^^^^^H 




V ' * T . 



^^■.■i 












































Chap. Ill 



EMBRYOLOGICAL SYSTEMS. 



225 



beg 



and controls the whole development. The embryo of the Verteb 



is a Vertebrate from the beginning, and does not exhibit at 



ipondence with the Invertebrates 



The 



any time a corre- 



mbryos of Vertebrates do not 



P 



m 



their development through other permanent types of animals. The fundamental 



typ 



is first developed, afterwards more and more subordinate characte 



app 



of 



From a more general type, the more special is manifested, and the more two forms 
animals differ, the earlier must their development be traced back to discern 
agreement between them. It is barely possible that in their first beginning 
all animals are alike and present only hollow spheres, but the individual develop- 
ment of the higher animals certainly does not pass through the permanent forms 



an 



of lower ones. What 



common in a higher group of animals 



developed in their embryos than what is special 



alway 



li 



sooner 



arises that which is less 



out of that which is most g 



g 



embryo of a g 



*yp 



until that which is most special appears 



Each 



becomes 



therefore 



of animals, instead of passing through other definite type: 

An embryo of a higher typ 



the contrary more and more unlike them 
never identical with another animal type, but only with 






Thus far do the statements of von Baer extend 



an embry 



i 



It 



he has clearly perceived the limitation of the different modes of embry 



ment within the 



evident from this, that 

>nic develop- 



npective branches of the 



animal kingdom 



but it is 



certain that his assertions are too general to furnish a key for the 



compar 



qually 
son of 



the 



successive changes which the different 



limits, and that he is still 



iponds in its individualization to the deg 



types undergo within their respective 
guely under the impression, that the development 

cation of structure. 



of compl 



1 The account which Huxley gives of Baer's 
views, (see Baden Powell's Essays, Appendix 7, 

* 

p. 495,) is incorrect. Baer did not "demonstrate 



main 



are 



that the classification of Cuvier was, in the 
simply the expression of the fact, that there 
certain common plans of development in the animal 
kingdom," etc., for Cuvier recognized these plans in 
the structure of the animals, before Baer traced 
their development, and Baer himself protests against 
an identification of his views with those of Cuvier. 
(Baer's Entwick., p. 7.) Nor has Baer demon- 
strated the " doctrine of the unity of organization 
of all animals," and placed it "upon a footing as 
secure as the law of gravitation," and arrived at " the 
grandest law," that, up to a certain point, the develop- 
ment "followed a plan common to all animals" On 
the contrary, Baer admits four distinct types of 



animals, and four modes of development He only of his great divisions. 

29 



adds : " It is barely possible that in their first begin- 
ning all animals are alike." Huxley must also 
have overlooked Cuvier's introduction to the " Reo-ne 
Animal," (2d edit., vol. 1, p. 48, quoted verbatim 
above, p. 193,) when he stated that Cuvier "did not 
attempt to discover upon what plans animals are con- 
structed, but to ascertain in what manner the facts of 
animal organizations could be thrown into the fewest 
possible propositions." On the contrary, Cuvier's 
special object, for many years, has been to point out 
these plans, and to show that they are characterized 
by peculiar structures, while Baer's merit consists 
in having discovered four modes of development, which 
coincide with the branches of the animal kingdom 
in which Cuvier recognized four different plans of 
structure. Huxley is equally mistaken when he says 
that Cuvier adopted the nervous system " as the base 



» 



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X. 





* 



226 



ESSAY ON CLASSIFICATION 



Part I 



This could hardly be otherwise, as long 

of animals had not been clearly distinguished 



as the different 



& 



of the structure 



CLASSIFICATION OF K. E. VON BAER. 



In conformity with his embryological investigations, K. E. von Baer proposes the following classification 



IV. 



I. Peripheric Type. (Radiata.) Evolutio radiata. The development proceeds from a centre, producing 

identical parts in a radiating order. 

II. Massive Type. (Mollusca.) Evolutio contorta. The development produces identical parts curved 

around a conical or other space. 

III. Longitudinal Type. (Articulata.) Evolutio gemina. The development produces identical parts 

arising on both sides of an axis and closing up along a line opposite the axis. 

Doubly Symmetrical Type. (Vertebrata.) Evolutio bigemina. The development produces identical 

parts arising on both sides of an axis, growing upwards and downwards, and shutting up along 

two lines, so that the inner layer of the germ is inclosed below and the upper layer above. The 

embryos of these animals have a dorsal cord, dorsal plates, and ventral plates, a nervous tube 
and branchial fissures. 

1°. They acquire branchial fringes; 

a. But no genuine lungs are developed. 

a. The skeleton is not ossified., Cartilagineous Fishes. 
B. The skeleton is ossified. Fishes proper. 



. 



b. Lungs are formed. Amphibia. 
a. The branchial fringes remain. 



Sirens 







^. The branchial fringes disappear. Urodela and Anura 
2°. They acquire an allantois, but 

a. Have no umbilical cord ; 

a. Nor wings and air sacs. Reptiles. 
|5. But wings and air sacs. Birds. 

b. Have an umbilical cord. Mammalia. 






Which 



Without 



Monotremata 



2°. After a short connection with the mother. Marsupialia 



p. W 



1°. The yolk sac continues to grow for a long time. 

The allantois grows little. Rodentia. 

The allantois grows moderately. Insectivora. 

The allantois grows much. Carnivora. 
2°. The yolk sac increases slightly. 

The allantois grows little. Umbilical cord very long. M 



for a long time. 



Placenta in simple masses 



* 

The allantois continues to grow 

Ruminants. 
The allantois continues to grow for a long time. Placenta spreading. Pachyderms 

and Cetacea. 



Compare Chap. II., Sect. 1 to 9. 












*S 



■ • 



■ ■ • 



■ 



70C 



* w 




. 




■ ... 

















Chap. III. 



EMBRYOLOGICAL SYSTEMS 



227 



CLASSIFICATION OF VAN BENEDEN. 



Van Beneden has also proposed a classification based upon Embryology, which was first sketched in 
his paper upon the Embryology of Bryozoa: Recherches sur l'anatomie, la physiologie et l'embryogenie des 
Bryozoaires, Bruxelles, 1845, 4to., and afterwards extended in his Comparative Anatomy: Anatomie comparee, 
Bruxelles, (without date, but probably from the year 1855,) 1 vol. 12mo. 



I. Hypocotyledones or Hypovitellians. (Vertebrata.) The vitellus enters the body from the ven- 



tral side. 



Cl. 1. Mammalia. (Primates, Cheiroptera, Insectivora, Rodentia, Carnivora, Edentata, Pro- 

boscidea, Ungulata, Sirenoidea, Cetacea.) 
Cl. 2. Birds. (Psittacese, Rapaces, Passeres, Columbae, Gallinae, Struthiones, Grallae, Palmipedes.) 

Cl. 3. Reptiles. 

Ichthyosauri.) 

Cl. 4. Batrachians. (Labyrinthodontes, Peromelia, Anura, Urodela, Lepidosirenia.) 
Cl. 5. F is he So (Plagiostomi, Ganoidei, Teleostei, Cyclostomi, Leptocardii.) 



(Crocodili, Chelonii, Ophidii, Saurii, Pterodactyli, Simosauri, Ple'siosauri, 



: 



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II. Epicotyledones or Epivitellians. (Articulata.) The vitellus enters the body from the dorsal 

side. 
Cl. 6. Insects. (Coleoptera, Nevroptera, Strepsiptera, Hymenoptera, Lepidoptera, Diptera, Orthop- 

* 

tera, Hemiptera, Thysanura, Parasita.) 
Cl. 7. Myriapodes. (Diplopoda, Chilopoda.) 
Cl. 8. Arachnides. (Scorpiones, Araneee, Acari, Tardigrada.) 
Cl. 9. Crustacea. (Decapoda, Stomapoda, Amphipoda, Isopoda, Laemodipoda, Phyllopoda, Lophy- 

ropoda, Xiphosura, Siphonostoma, Myzostoma, and Cirripedia.) 





















III. Allocotyledones or Allovitellians. (Mollusco-Radiaria.) The vitellus enters the body neither 

• from the ventral nor from the dorsal side. 
Cl. 10. Mollusca. Including Cephalopoda, Gasteropoda, Pa3cilopoda, and Brachiopoda. (Acephala, 

Tunicata, and Bryozoa.) 
Cl. 11. Worms. (Malacopoda, Annelides, Siponculides, Nemertini, Nematodes, Acanthocephali, 

Scoleides, Hirudinei.) 

* 

Cl. 12. Echinoderms. (Holothuriae, Echinides, Stellerides, Crinoides, Trematodes, Cestodes, 



Rotiferi, Planarise.) 



Including Tunicata, Bryozoa, Anthozoa, Alcyonaria 



Cl. 13JPolyps.H 

(Ctenophorae, Siphonophoras, Discophorse, Hydroids, Anthophoridas.) 
Cl. 14. Rhizopods. Only the genera mentioned. 
Cl. 15. Infusoria. Only genera and families mentioned. 



and Medusae, as orders. 



Van Beneden thinks the classification of Linnaeus truer to nature than either 
that of Cuvier or of de Blainville, as the class of "Worms of the Swedish naturalist 
corresponds to his Allocotyledones, that of Insects to his Hypocotyledones, and the 

* r 

four classes of Pisces, Amphibia, Aves, and Mammalia to his Hypocotyledones. 
He compares his primary divisions to the Dicotyledones, Monocotyledones, and 

Acotyledones of the vegetable kingdom. But he overlooks that the Cephalopods 






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- 



228 



ESSAY ON CLASSIFICATION. 



Part I 













Allocotyledones, and that any group of animals which unites Mollusks, Worms 



and Radiates in one 



g 



mass cannot be founded upon correct principle 



As 



there 



to his classes, I can only say that if there are natural classes among animals, 

X 

never was a combination of animals proposed since Linnseus, less likely to 
answer to a philosophical idea of what a class may be, than that which unites 
Tunicata with Polyps and Acalephs. In his latest work, Van Beneden has introduced 
in this classification many important improvements and additions. Among the 

introduced in brackets in the 
These changes relate chiefly 



additions, the indication of the orders, which 



are 



diagram above, deserve to be particularly noticed. 

to the Mollusks and Polyps; the Tunicata and Bryozoa being removed from the 



Polyp 



to the Mollusks 



The Acalephs and Polypi, however, are still considered 



as forming together one single class. 



The 



comp 



instituted by Van Beneden b 



his classification of the 



animal kingdom and that of the plants most generally adopted now, 
call again attention to the necessity 
kino-dom, with the view 



© 



concerning 



_ f leads me to 

of carefully scrutinizing anew the vegetable 
of ascertaining how far the results I have arrived at 
the value of the different kinds of natural groups existing among 



animals, 1 apply also to the plants. It would 



tainly be premature to assume 



that because the branches of the animal kingdom are founded upon different plans 
of structure, the vegetable kingdom must necessarily be built also upon different 

There are probably not so many different modes of development among 




as 



among animals; unless the reproduction by spores, by naked polyem 



seed 



by 

seed 



giospermous monocotyledonous seeds, and by angiospermous 
connected with the structural differences exhibited by the 

Monocotyledones, and Dicotyledones, be considered as 

ans of structure. But even then these 




plants 

bryonk 

dicotylodori 

Acotyledones, Gymnospermes., 

amounting to an indication of different 

differences would not be so marked as those which distinguish the four branches 
of the animal kingdom. The limitation of classes and orders, which presents com- 
paratively little difficulty 
whilst botanists have thus far been much more accurate than zoologists in charac- 

arities of the two 



in the animal kingdom, is least advanced among plants 



o 



terizing families 



This is, no doubt, chiefly owing to the pecul 



g 



kingdoms 



It must be further remarked, that in the classification of Van Beneden the 



animals united under the name of Allocotyledones are built upon such 



ely 



different 




of structure, that their combinat 



should of itself satisfy any 



unprejudiced observer that any principle which unites them in that way cannot 



be true to nature. 



' 



I 



' 







1 See Chap. IL, p. 137 to 178. 







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I 










< 

1 










Chap. III. 



EMBRYOLOGICAL SYSTEMS. 



229 



DIAGRAM OF THE DEVELOPMENT OF ANIMALS BY KOLLIKER. 

Kolliker (A.,) in his Entwickelungsgeschichte der Cephalopoden, Zurich, 1844, 1 vol. 4to., p. 175, 
has submitted the following diagram of the development of the animal kingdom. 

A. The embryo arises from a primitive part. (Evolutio ex una parte.) 

1°. It grows in two directions, with bilateral symmetry. (Evolutio bigemina.) 

a. The dorsal plates close up. Vertebrata. 

b. The dorsal plates remain open and are transformed into limbs. Articulata. 

2°. It grows uniformly in every direction. (Evolutio radiata.) And 

a. Incloses the embryonal vesicle entirely. 

a. This takes place very early. Gasteropoda and Acephala. 



£>. This takes place late. 



,) L i m a x . 



b. Contracts above the embryonal vesicle. (Genuine vitelline sac.) Cephalopoda. 
A. The whole body of the embryo arises simultaneously. (Evolutio ex omnibus partibus.) 



1°. It grows in the direction of its transverse axis, 



a. 



With 



Radiata. 



) 



b. With the fore body, and 



a. The hind body does not grow. Acalephs. 
/3. The hind body grows longitudinally. Polypi. 
2°. It grows in the direction of its longitudinal axis. Worms. 

I have already shown how unnatural a zoological system must be which is 



based upon a distinction between total or partial segmentation of the yolk 



No 



more can a 



diagram of the development of animals, which adopts this difference 



as fundamental, be true to 



nature, even though it is based 



upon 



real facts 



We 



ht 



never to single out isolated features, by which animals may be united or sep- 
arated, as most anatomists do; our aim should rather be to ascertain their general 
relations, as Cuvier and K. E. von Baer have so beautifully shown. 2 I think also, 

- 

that the homology of the limbs of Articulata and the dorsal plates of Vertebrata 



more than questionable 



The distinction, introduced between Polyps and Acaleph 



and these and the other Radiates, is not any better founded. It seems also quite 
inappropriate to call the development of Mollusks, evolutio radiata, especially after 
Baer had designated, under that same name, the mode of formation of the branch 
of Radiates, for which it is far better adapted. 



gegenseitige Verwandtschaft der Thiere zu erlangen, 
die verschiedenen Organisationstypen 



1 Chap. DEL, Sect. 1, p. 171. 

2 The principles of classification advocated by I 

Baer are so clearly expressed by him, that I cannot von den verschiedenen Stufen der A u s - 

resist the temptation of quoting some passages from bildung stets unterscheiden. Dass man diesen 

■ 

the paper already mentioned above, p. 224, especially Unterschied gewohnlich nicht im Auge behalten hat, 

now, when I feel called upon to oppose the views of scheint uns zu den sonderbarsten Zusammenstel- 

one of his most distinguished colleagues. u Vor alien lungen gefiihrt zu haben." Beitrage, etc., Acta 



Dingen muss man, urn eine richtige Einsicht in die 



Nova, vol. 13, p. 739. 









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230 



ESSAY ON CLASSIFICATION 



Part I. 



CLASSIFICATION OF YOGT. 






44 

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I. Vertebrata. Yolk ventral. 

Cl. 1. Mammalia. 1°. A 



\ 



Mar 



2°. Placen- 



taria. Ser. 1. Ord. Cetaeea, Pachydermata, Solidungula, Ruminantia, and Edentata; 
S. 2. Pinnipedia, Carnivora ; S. 3. Insectivora, Volitantia, Glires, Quadrumana, Bimana. 

Ser. 1. Insessores; Ord. Columbse, Oscines, Clamatores, Scansores, Rapta- 



Cl. 2. A v e s . 

tores ; Ser. 2. Autophagi ; Ord. Natatores, Grallatores, Gallinacea, Cursores, 
Cl. 3. Reptilia. Ord. Ophidia, Sauria, Pterodactylia, Hydrosauria, and Chelonia. 
Cl. 4. Amphibia. Ord. Lepidota, Apoda, Caudata, Anura. 

Cl. 5. Pisces. Ord. Leptocardia, Cyclostomata, Selachia, Ganoidea, Teleostia. 
II. Articulata. Yolk dorsal. 

■ 

Cl. 6. Ins e eta. Sulci. 1. Ametabola; Ord. Aptera. Sulci 2. Hemimetabola; 

Ord. Hemiptera and Orthoptera. Subcl. 3. Holometabola; Ord. Diptera, Lep- 

idoptera, Strepsiptera, Nevroptera, Coleoptera, Hymenoptera. 
Cl. 7. Myriapoda. Only divided into families. 



Cl. 8. Arachnida. 



Series 1 . Pycnogonida and Tardigrada ; Ord. Acarina, Araneida. 



Series 2. With three families. 



Cl. 9. Crustacea. 



Subcl. 1. Entomostraca; Ord. Cirripedia, Parasita, Copepoda, 



Phyllopoda, Trilobita, Ostracoda. Subcl. 2. Xiphosura. 



Subcl. 3. Podoph- 



t h a 1 m a ; Ord. Stomapoda, Decapoda. Subcl. 4. Edriophthalma; Ord. La3- 

■ 

mipoda, Amphipoda, Isopoda. 



III. Cephalopoda. 



Yolk cephalic. 



Cl. 10. Cephalopoda. Ord. Tetrabranchiata and Dibranchiata 



IV. Mollusc a. Irregular disposition of 



organs. 



Cl. 11. Cephalophora. Subcl. 1. Pteropoda. Subcl 2. Heteropoda. 



V 



Subcl 



3. Gasteropoda; Ord. Branchiata and Pulmonata. 



Chitonida. 



Cl. 12. Acephala. Subcl 1 . B r a c h i o p o d a ; Ord. Rudista, Brachiopoda. Subcl 2 

Lamellibranchia; Ord. Pleurochoncha, Orthoconcha, Inclusa. 
Cl. 13. Tunicata. Ord. Ascidiae, Biphora. 



ilies. V- 



Cl. 14. Ctenophora. Only subdivided into families, y Molluscoidea. 
Cl. 15. B r y o z o a . Ord. Stelmatopoda, Lophopoda. 



V. Vermes, 



Organs bilateral. 



Cl. 16. Annelida. Ord. Hirudinea, Gephyrea, Scoleina, Tubicola, Errantia. 

Cl. 17. Rotatoria. Ord. Sessilia, Natantia. 

Cl. 18. Platyelmia. 1°. Ord. Cestoidea, Trematoda. 2°. Ord. Planarida, Nemertina 

Cl. 19. Nematelmia. Ord. Gregarinea, Acanthocephala, Gordiacei, Nematoidei. 

■ 

VI. Radiata. Organs radiate. 






Cl. 20. Echinodermata. Ord. Crinoidea, Stellerida, Echinida, Holothurida. 

Cl. 21. Siphonophora. Only subdivided into families. 

- 

Cl. 22. Hydromedusae. Not clearly subdivided into orders. 

Cl. 23. Polypi . Ord. Hexactinia, Pentactinia, Octactinia. 



» 



VII. Protozoa. 



Cl. 24. Infusoria. Ord. Astoma and Stomatoda. 

» 

■ 

Cl. 25.' R h i z o p o d a . Ord. Monosomatia and Polythalamia 



I 









► 





















V 







I 



Chap. III. 



EMBRYOLOGICAL SYSTEMS 



231 



1 



> 



\ 



The classification of Vogt (Zoologische Briefe, q. a., p. 180) presents several 

* 

new features one of which is particularly objectionable. I mean the separation ol 
the Cephalopoda from the other Mollusks, as a distinct primary division of the 
animal kingdom. Having adopted the fundamental distinction introduced by Kol- 
liker between the animals in which the embryo is developed from the whole yolk, 
and those in which it arises from a distinct part of it, Yogt was no doubt led 



his interesting investig 



upon 



Actseon 



which 



to this step in consequence of 

he found a relation of the embryo to the yolk differing greatly from that observed 



by Kolliker in Cephalopods 



B 



as I have already shown above, this cannot 



any more justify their separation, as branches, than the total segmentation of the 



yolk of Mammalia could justify the separati 



of the latter from the other Verte 



brates. Had the distinction made by Vogt, between Cephalopod 



and the other 



Mollusks, the value he 



g 



to it, Limax should also be separated from the 



other Gasteropods 



The 



that Protozoa produ 



no 



gg 



deserves 



ipecial 






said in the preceding sections respecting 



consideration after what has already b 

the animals themselves. As to the transfer of the Ctenopl 

Mollusks, it can in no way be maintained. 

Before closing this sketch of the systems of Zoology, I 
opportunity of adding one general 



to the typ 



of 



cannot forego the 



remark. If we remember how completely hide 



pendent 



the investigations of 



K. E. von B 



were from those of Cuvier, how 



different the point of view was from which they treated their subject, the one 
considering chiefly the mode of development of animals, while the other looked 
mainly to their structure; if we further consider how closely the general results 

it is impossible not to be deeply 
they both advocate, that the animal king- 



ived agree throughout 



at which they have 

impressed with confidence in the opinion 

dom 



exhibits four primary divisions, the representat 



upon four different 
modes of developu 




up 



js of which are organized 
according: to four different 



ans of structure, and grow 

This confidence is further increased when we perceive 
that the new primary groups which have been proposed since are neither char- 



acterized by such different pi 



developed according to such different modes of 



development, but exhibit simply minor differences 



It 



is, indeed 



a very 



fortu- 



nate tendency, which prevails now almost 



rsally among naturalists, with refer- 



ence 



to all kinds of groups, of whatever value they may be, from the branches 



down to the species, to separate at 



from one another any types which exhibit 



marked differences, without even inquiring first whether these differences are of 
a kind that justifies such separations. In our systems, the quantitative element 



of differe 



prevails too exclusively over the qualitat 



If such distinc 



tions are introduced under well-sounding names, they are almost certain to be 



adopted; as if science gained any 



thing 



by concealing a difficulty under a Latin 



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232 



ESSAY ON CLASSIFICATION 



Part I. 



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** 






or Greek name, or 



was advanced by the additional burden of a new nomencla 



ture. 



Another objectionable practice, prevailing quite as extensively also, consists 



in the chan 



ge of names, or the modification of the extent and meaning of old ones 



without the addition of 



new information or of new views. If this practi 



is 



not abandoned, it will necessarily end in making Natural History a mere matter 



of nomenclature, instead of fostering its higher philosophical character 



Nowhere 



is this abuse of a useless multipl 



of names so keenly felt as in the nomen 



clatu 



of the fruits of plants, which exhibits neither insight into vegetable mor 



phology, nor even accurate observation of the material facts 



- 

May we not return to the methods of such men as Cuvier and B 



wer 



never ashamed of expressing their doubts in difficult 



and 



were 



r, who 
always 



ready to call the attention of other observers to questionable points, instead of 
covering up the deficiency of their information by high-sounding words! 

In this rapid review of the history of Zoology, I have omitted several classi- 
fications, such as those of Kaup and Van der Hoeven, which might have afforded 
an opportunity for other remarks, but I have already extended this digression 
far enoi 



gh to show how the standards I have proposed 



my second chapt 



may assist us in testing the value of the different kinds of groups generally 
adopted in our classifications, and this was from the beginning my principal object 
in this inquiry. The next step should now be to apply these standards also to 






the minor divisions of the animal kingdom, down to the 



g 



and species, and 



to do this for every class singly, with special reference to the works of mono 



phers. But this is such an herculean task, that it 



can only b 



plished 



by the combined efforts of all naturalists, during many years to come. 



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