Ernst Mayr Library
‘Museum of Comparative Zoology
Harvard University

OBSERVATIONS
ON THE
NATURAL HISTORY AND STRUCTURE

OF THE

PROTEUS ANGUINUS.

By Sic. CONFIGLIACHI ann Dr RUSCONI.

Tue Proteus Anguinus is an animal that has much excited
the curiosity of zoologists, and many poimts in its natural histo-
ry and anatomy still remain undecided. Of late this animal
has been examined with far greater minuteness, and under much
more favourable circumstances than heretofore, by two Italian
naturalists of distinguished ability; and the results of their la-
bours have been given to the world in a work, entitled, ‘* Del
Proteo Anguino di Laurenti Monografia, publicata da Pietro
Confighachi, Professore Ordinario di Fisica nella Imperiale
Regia Universita di Pavia, e da Mawro Rusconi, Dottore in
Medicina e Publico Ripetitore di Fisiologia.”—Pavia, 1819.
This work is illustrated by excellent engravings, from most ac-
curate drawings by Dr Rusconi himself; and as only a few co-
pies of it have yet reached this country, perhaps an abridged
account of the labours of these ingenious naturalists, which have
so much contributed to clear up the doubts respecting this sin-
gular animal, may not be unacceptable to such as take an inte-
rest in such subjects, and have not the opportunity of consult-
. ing the original work.

It appears that the first knowledge of this rhcinial was com-
municated to the public by Dr Laurenti, in his Synopsis Rep-
tilium, about the year 1768. A fuller description of it was pu-
blished by Dr Scopoli in 1772; and im the new edition of the
Systema Nature of Linneus, edited by Ginelin, notice is taken

hae

»

a Observations on the Natural Histore
Y

of it. After this Hermann and Schretbers wrote on the Pre-
teus, but described only its external parts, and contributed no-
thing to clear up the many doubts and conjectures vespe il
it. a this state of uncertainty, ‘Pr Schreibers first had recourse
to anatomy, as the only satisfactory mode of gaining correct in-
formation: but unfortunately he possessed only three Protei,
which had been sent to him from Carniola, preserved in spirits ;
which circumstance precluded him from giving that complete
mformation which.might otherwise have been expected from so
eminent a naturalist. His description was published in 1801;
and among many excelient observations, he points out the stri- -
king differences of form in the lungs of the Sirena lacertina,
compared with those of the Proteus.*. Next to Schrerbers, we
_have to notice two zoologists of the highest celebrity, MM.
Cuvier and Rudolphi, both of whom examined the mternal
structure of this animal. ‘The former first discovered, and ac-
-curately described the organs of generation m the female, and
established, on a solid foundation, that the Proteus was not a
larva, as many had supposed, but a perfect animal’; an opinion
now generaily followed, and confirmed by the recent observa-
‘aons of Rudolphi, who has described the generative system in
the maie, and communicated observations on the globules of the
blood, which, ia'this animal, seem to be of an unusually large
size.

* The authors here observe in a note, that Dr Schreibers, aware of the im-
perfection of his former description, had lately resumed the subject, and applied
himself not less to study the habits than the internal structure of the Proteus.
Uninformed of his intentions, the authors had transmitted to him. at Vienna a
copy of their plates, with the accompanying explanations, and a request that he
would. favour them with his opinion of their labours, and his advice, where it
might. appear to him that they had: been mistaken. With a liberality that does
him. great honour, he replied, ‘‘ Since you have anticipated me,. continue the
work you have so well begun: when the work shall be published, I will cause a
translation of it to be made into our language, under my own eyes,.and as I have
procured very many of these animals, with the view of instrueting myself on
various points, I shall:be able to add:to the translation not a few observations, and
perhaps some plates.” The authors observe, that they: announce, with great
satisfaction to zoologists, this intended translation of their work, and the addi- _
tions it is destined to receive. The fame of Sig. Schreibers renders it unneees-
sary for them to say more; they add only, that he has devoted many years to
this subject, and sacrificed more than 100 protei to his learned’ researches.

Lp ; a ~ 4 U
of the Proteus Anguinus. 3

The Proteus Anguinus lives and multiplies'in the water of
ertain subterranean caverns of Garniola. The province in
which these caverns ‘occur-is divided by a chain of mountains of
secondary or transition limestone, on which rest many’ hills of
posterior formation. Both im the mountains and hills are many
caverns and subterraneous passages ‘stretchimg in various direc-
tions, and lying indifferent planes. These caverns communi-
cate with one another, so that the water ‘first coilected im those
at a higher level, falls: down and circulates through subterrane-
ous ckannels, ‘till it settles in the lower caverns, some of which
are of vast size and depth. Two of the most remarkable of
these caverns are situate near Adelsberg, a village lying mid-
way between Trieste and Lubiana. One of them, called the
Cavern of Adelsberg, is close to the village, and ‘the other,
named the Cavern of Maddalena, is only a few mies distant.
It is in this last that the peasants at present ‘go‘tofish for *Pro-
tei. On the 2d of August 1816, the ‘authors, attended by three
peasants, furnished with torches, ‘and with a small net im the
shape of a bag, fixed te the end of a staff, prepared to enter
this cavern. At 5 o'clock a. m., the temperature of the exter-
nal air at the mouth-of the cavern was 48° Fahr*. ‘As they de-
scended, they passed through spacious apartments, some of
them clothed with stalactites. and:cale-spar, which reflected with
great brilliancy the light of the torches, and exhibited a mag-
nificent appearance. Others appeared like pits of mud, which
rendered the walking very inconvenient. At length they reach-
edia stagnant pond, about 30 feet broad, and at a depth below
the surface ef about 1.70 toises. In this pond they saw one
proteus, but did not sueceed in taking hum; and from ‘the
water beng turbid, and in too great -quantity, in consequence
of heavy rains the day before, they were ebliged to reascend,
_after having been two hours in the cavern, without taking a
single proteus. The temperature of the water in this pond
was 55°, and that of the air of the cavern was stationary at

* In the original, the temperatures are given according to the scale of Reav-
mur, which are here converted into the corresponding degreesof Fahrenheit. As
great precision is not necessary, the nearest whole numbers of Fahrenheit are taken,
an order to avoid fractions.

4 Observations on the Natural History

- 54°.5, while the thermometer, left in free air at the mouth of
the cavern, had risen from 48° to 59°. The specific gravity of
the water in the pond was to that of distilled water, at the
same temperature, as 101°.5 to 100°. These animals are found
in other pits of stagnant water in Carniola and elsewhere. The
first protei described by Laureniti and Scopoli were not’procured
from the Lake of Zirknitz, as has been commonly represented,
nor from any of the caverns of Carniola, but were found acci-

dentally by the peasants in small puddles of water near the
mouths of certain caverns, a little distant from Sittich, on the
road to Newstadt, in Lower Carniola, cast out of the caverns
probably by the overflowing of their water after heavy rains.

_ It was not till the year 1797, that these animals were discover-
ed in the caverns of Maddalena. At present, the peasants of
Adelsberg, when the season suits, go to fish for them, and pre-
serve them alive, till they sell them to the curious who visit
Carniola, or convey them to Trieste, where they are sold for
the small sum of two or three lire each.

Regarding the form and habits of the proteus, the authors ob-
serve they shall be brief. As to external form, the accompanymg
figure, (see Plate,) drawn with al) possible care and attention,
will much more clearly make it known than any words can do ;
and on this point, therefore, they profess to note down only such
things as could not be exhibited by a figure, or which the
draughtsman could but imperfectly represent. With regard to
habits,—to describe these with minuteness and perfect accuracy,
it would be necessary to observe the animal in its native caverns,
and not in the state of captivity in which it has been seen by —
them. They will faithfully state, however, all they have ob-
served of these animals, while kept in vessels within doors for
‘more than two years: and from the observations thus made,
and from comparisons between the proteus and aquatic salaman-
der, will deliver the best judgment they have formed of their
habits and way of life.

The authors are not able to speak positively either of the age
or of the size at which these animals arrive. None of the pro-
tei seen by them exceeded 12 inches in length, and the smallest
they have heard of was only four *: It was seen by Dr Pockels,

of the Proteus Angwinus. 5
a skilful anatomist, and not less estimable for his learning than,
for the suavity of his manners. There is reason to believe,
that, when at their full growth, they reach to 14 inches or
even more. That described by Schreibers in 1801 was 13
inches in length. With regard to age, there is reason to think
they are pretty long lived ; for the Archduke John of Austria,
a zealous cultivator and liberal patren of natural science, kept,
in a subterranean grotto, constructed for the purpose, several of
these animals, one of which lived eight years, and acquired a
size greater than ordinary.

When viewed alive, and in water, the body of the proteus
appears at first of a cylindrical form, but when more attentively
surveyed, it is seen to be somewhat flattened on the sides, espe-
cially towards the tail, which, beyond the lower limbs, is redu-
ced at length to the shape of a spatula. The back and head
of the animal are of a whitish-red colour, which, on the sides
and tail, inclines to violet. The belly, on the contrary, is
white, though even there, in the region of the liver, it has a
bluish cast, like that of the human veins, seen through a very
fine and delicate skin. An illustrious writer, who had observ-
ed a proteus only after having been kept in spirits, has describ-
ed the skin as very opaque; but we, say the authors, who have
seen many protei alive, can with confidence affirm, that so far
from being opaque, the skin of these animals is, almost beyond
belief, transparent,—to such a degree, indeed, that the colours
or tints, as painters express it, are so very diaphanous, that, to
represent it by words, is quite impossible, and by the pencil
sufficiently difficult. Those unacquainted with pamtmg may
doubt our assertion, but those the least instructed in that art,
and who know by experience how difficult it is to imitate a
diaphanous tint, will remain -painfully convinced of this, when
told that the diaphanity of the tints of the Proteus Anguinus
(be the human skin as white, morbid, and subtile as you please)
exceeds by far that of the colours of the human body. But
the flesh-colour of this animal in course of time changes; and
this happens more or less quickly, according as he is more or
less exposed to the light. From whitish-red the skin’ passes by

* The authors employ the old French measures.

6 Obscroations on the Natural History

degrees to violet; so that to preserve the natural colour, it is
necessary to keep the animal always in obscurity.

The skin of this reptile, like that of eels, is every where be-
smeared with a viscid mucus; and when viewed with a lens, it
is observed to be studded with minute reddish spots, and with
innumerable pores. By reason of this mucosity, the proteus
easily slides out of the hand, and while alive, is with difficulty
fixed down to any substance for the purpose of dissection. In
attempts to do this, say the authors, we have destroyed many
protei, and have observed, that, when about to die, the body
has become covered with so much mucus, that it appeared diffi-
cult to believe how they were able to afford it.

In enumerating the external organs, the authors pass over for
the present the eyes and gills, till they come to describe anato-
mically the organs of sense and of circulation. As to the mouth,
it differs from that of other reptiles. The superior lip, after co-
vering the teeth, is continued a little downward over the inferior
one in front; and, on the other hand, the inferior lip is conti-
nued upward over the superior one on the sides of the mouth.
The size of the head and tail is, m some protei, larger in prepor-
tion to the body than in others, depending probably on the rela-
tive age of the animal, and not on particular seasons, as is the
case in the aquatic salamander.

When a proteus that has been kept some time in darkness is
observed with caution, he is always found to be resting quietly
at the bottom of the vessel, and in the position nearly repre-
sented in the figure. But if the vessel be quickly uncovered,
he suddenly begins to move, is much agitated, and seeks always
that part of the vessel which is darkest. If now that part of the
vessel be exposed to the light, the animal again begins to move,
and soon his gills assume a redder tint, and the rest of the body
also becomes of a redder hue. In fact, the light gives pain,
and the animal exerts himself to avoid it. This disposition to
escape from light is the more remarkable, as the eyes of this
animal are incredibly small, and so buried beneath the skin, that
a person even apprized of their situation, must use great dili-
gence to discern them; whence those are not without excuse
who have demied altogether the existence of these organs.

of the Proteus Auguiniis. 4

. This reptile feeds on worms, ‘small bivalves, and snails. In
this he resembles the salamander, but he bears fasting much
better, being able to live two years and even more without ali-
ment. When taken from his natural habitation, and exposed
to the vicissitudes of the season, like other perfect reptiles, he
hides himself during the winter, is inert, and refuses food.

The proteus does not live long if he is taken out of the water.
When he becomes dry, he dies more or less quickly, according
as the season is more or less ‘warm, being less able to sustain life
under such circumstances than fishes. But if the proteus die
more speedily when out of water; in water, on the contrary, he
lives better than fishes, ‘since, caeteris paribus, he has not such
frequent need‘ of a renewal of the water as fishes have. When
placed in a small vessel, in water at the temperature of 68°.5,
the proteus, like fishes, rises at times to the surface to take in
air by the mouth. -In doing this, he opens his mouth ‘as wide
as he ‘is able, and again rejects the air very quickly through the
branchial apertures. In the act of taking in air, and passing it
through these apertures, he makes a certain noise not unlike
that made by a syringe, when a little air insinuates itself with
the liquid into the tube ; but when the animal is removed from
the water, and then inspires air by the mouth, this noise is‘not
heard. In the escape of the air by the branchial apertures, when
the animal breaths in air, some minute bubbles remain attach-
ed to the margins of the apertures, or to the roots of the gillss
and the gills themselves collapse and fall down against the sides
of the head. On the contrary, when the air is received into the
mouth while the animal is in water, it escapes freely through the
branchial apertures, and rises in bubbles to the surface.

The necessity of inspiring air from time to time, is more or
less great, according as the water-is more or less impure ; and it
has a more direct relation to the temperature than to the quan-
tity of water. It is greatest when tlie animal is removed from
the water ; he is then seén to take in air, and reiterate this ope-
ration ; his breathing becomes weaker, and at the end of two or
three hours he ceases to breathe. But if the water of the vessel
have the temperature of 68°.5, and be also frequently renewed,
he then has no need of rising to the surface to inspire air, and
this 1s still less necessary if the water be in large quantity, or

|

8 Observations on the Natural History

gently flowing. The authors enclosed a proteus in a box, per-
forated with holes, which was then sunk in a large lake, and
kept for three months and a half beneath the surface. At the
end of this time, on examining the box, the animal was found
extremely lively, which clearly shewed, that submersion in wa-
ter for so long a period had in no way injured its vital economy.
‘The temperature of the water, through the whole period, va-
ried little from 66°. But if the temperature be under 54°, say
from 45° to 48°, it is of little consequence to the proteus whether
the water be much or little, fresh or stagnant, since at so low a
temperature, he remains always as if immoveable at the bottom
of the vessel, and never comes to the surface to inspire air. For
four months together, two protei have been kept in a small ves-
sel of water of the temperature from 43° to 45°,5, and have lived
very well, although the water has not been once changed,

In the ordinary act of changing the water in-which the ani-
mals are kept, if the fresh water be of a lower temperature than
that which it replaces, the proteus becomes somewhat pale, and
the gills, previously of a vermilion hue, turn pale, and collapse
in an instant. ‘This observation can, however, be made only in
summer; for in winter, when the temperature is from 45° to
48°, if the proteus be placed in obscurity, and left perfectly
quiet, the gills are always pallid, collapsed, and very small ;
and, should he be even molested, they do not appear so branch-
ed or red, as we sce them when in a temperature varying from
68° to 72°; in which case, if the animal be at the same time
well nourished, the gills are always in the erected state repre-
sented in the drawing. Should the water be raised successively
to 77°, 88°, or 104°, it is observed, that at 88° the animal is
much disturbed, expels bubbles of air through the branchial

"apertures, moves rapidly in the vessel, and attempts to escape :
the gills become very red, and are so turgid with blood, that
their points are turned upwards. And when the temperature is
carried to 104°, the distress of the proteus is very great : he
makes such movements and contortions of the body as if about
to die, but which soon cease, if the temperature be reduced to
its proper point. Hence it seems that the proteus is not able te
live long in a temperature much above 77°.

of the Proteus Anguinus. 9

With regard to the faculties of sense, those of hearing and
seeing appear to be very weak ; but those of touch and of smell,
particularly the latter, exquisitely acute. When some small
fishes were put into the vessel containing a proteus, it was amu-
sing to see the animal direct his snout towards his prey, though
he could not possibly see it, and afterwards seize it with the
greatest celerity when a fish passed near him. But it may be
asked, if the sense of sight be so weak, why is it that this ani-
mal so anxiously avoids, the light? It is probable that the con-
stant desire of obscurity arises from the painful action of light,
not on the eye, but on the skin. From the experiments, how-
ever, of Sig. Rudolphi, it appears that this animal may in time
be brought to bear the presence of light:

In a future communication, I propose to exhibit a general
sketch of the anatomy of this animal, more particularly of its cir-
culating and respiratory organs, illustrated by a few figures from
the beautiful engravings with which the authors have adorned
their work.

EDINBURGH,
January 20. 1821.

Observations on the Natural History and Structure of the Pro-
teus Anguinus. By Prof. Conrieniacnt and Dr Rus-
CONI. (Continued.)

H AVING, in the former communication, detailed the lead-
ing circumstances in the natural history of the Proteus, I pro-
ceed now to exhibit a sketch of the anatomy of this animal,
more particularly of its circulating and respiratory organs.

1. Of the Skeleton.

The authors commence their anatomical description of the
Proteus, by treating first of the skeleton. The pieces which
compose it, they observe, differ not only as to form, but also in
regard to flexibility and herdness. Some parts are membranous,
others cartilaginous, others between cartilage and bone, and
others are entirely osseous. With respect to natural hardness,
the inferior maxilla, and the arches which support the gills and
form the branchial apertures, come first; next, the vertebrze ;
then the cranium; afterwards, the four extremities; and final-
ly, the pelvis and scapula, and the two pieces which concur
with the latter to form the articulation of the shoulder. The
rigidity of the bones will doubtless encrease with age; but the
authors cannot pronounce on the actual age of any of the ani-
mals they dissected, nor assert with confidence if they had ar-
rived at their greatest size. In several, however, the organs of
generation were perfectly developed; and one that was dissect-.
ed, and which had been previously kept alive, in their posses-
sion, for ten months, did not appear to have increased an atom
in size; nor were the bones different, in any respect, from those
of other proter. In general, however, they regard the bones
of the proteus as more tender than those of the aquatic sala-
mander.

In the craniwm of these animals there is no temporal fossa,
nor zygomatic process, nor orbit to be seen; and the bones

°
Qn

g Observations on the Natural History

themselves are so thim that the entire mass of brain is some-
times visible through them. The temporal bones send pro-
cesses forward, cia articulate with the lower j jaw. The two
frontal boxes are long, and lie nearly in the same plane witl:
the infra maxillary; but the cranium is a little depressed, m
that part formed by: the parictal bones. Both jaws are fur-
uished with teeth, which are arranged in a beautifully sym-
metrical order along their respective borders. ‘These teeth
have a conical figure. In the upper jaw, their number is
about 60; m the lower jaw there are 70, disposed in two
rows parallel to one another. The lower jaw is horizontal,
and has no ascending process where it articulates with the
temporal bone. ;

The os hyoides m the proteus is ee : its anterior n basnebee
extend backwards and outwards, and then bending upwards,
proceed to be attached by a large tendon to the sides of the
cranium, behind the articulation of the lower jaw *. The small
arches which sustain the gills are three on each side; the
first, or exterior one, is the largest; it is connected anteriorly —
with the posterior ‘extremity of the os hyoides, by the inter-
medium of a little bone: the second, or middle arch, is also.
furnished with an intermediate bone, which 1s attached to the
intermediate bone of the first arch: the third, or imterior
arch, has no intermediate bone, but is connected directly with.
the second by means of a cartilage. The relative size and
position of all these parts may be seen in Plate VI. Fig. 1, where
the bones of the head, viewed from below, are cep ee
eight times greater than natural. | )

From: the occiput to the extreme point of the tail there
are 59 vertebre, all of which, except the last, have an osseous
structure. Of these, 29 belong to the neck and back, 3 to
the sacrum, and 27 to the tail. The first vertebra, or atlas,

* Tn the Plates, the animal is exhibited in a reversed positic, but in the ana-
vomical descriptions, is supposed to be placed on his four feet; hence the terms
anterior, or forward, look towards the head; posterior, or backward, towards the
tail; superior, or upward, to the back; and inferior, or downward, towards the —
belly of the animal. The terms interior: and exterior are used to denote relative:
nearness to, or distance, from the median line; and those of internal and external.
refer simply to the inside or outside of the animal.

and Structure of the Proteus ANQUINUS. o

has a peculiar form, possessing a dentiform process and articu-
lating surfaces, on which the condyles of the occiput rest. All
the others consist of a body, contracted in the middle like an
hour-glass, and, except towards the extremity of the tail, each
vertebra is furnished with four articulating apophyses, or pro-
cesses, two anterior, and two posterior. The two anterior pro-
cesses of each vertebra are covered by the posterior ones of the
vertebra above it; and its two posterior ones cover, in turn, the
anterior processes of the vertebra below: so that, viewed from
above, the vertebree seem to be placed in the manner of tiles.
Beside these processes, all the vertebrae, except the atlas
and some of the caudal, have two transverse processes, which
vary a little in form in different parts of the spme. In the third
vertebra, these processes, which in the bone above were entire,
separate into two portions of unequal length, and to the shorter
portion is attached the riidiment of a rib. The same structure
is continued downward to the ninth vertebra, where this parti-
tion of the process ceases. Below the ninth vertebra, these trans-
‘verse processes are formed of two thin laminz united together,
and stand out fromthe body ef the bone, like the unfledged
wings of a young bird. ~Gradually these laminz diminish and
disappear, so that about the third or fourth caudal vertebra
they exhibit only a simple spine; and this spine, continually be-
coming smaller, vanishes also about the tenth caudal vertebra.
In addition to these transverse processes, the vertebra of these
animals have also their spinous processes, which spring from the
extreme posterior and superior border.of each vertebra. Beside
having the dorsal spinous processes, the caudal vertebree are fur-
nished with two other spmous processes on the opposite surface of
the bone, and which, from their position, may be named ventral.
These spring from the roots. of the transverse processes on each
side, and proceeding im a parallel course, very soon unite, and
form a canal, through which the blocdvessels, that are distri-
_buted to the tail, are continued. | By the gradual diminution of
the processes, this canal is lost before reaching the extremity of
the tail.
So much for the bones of the cranium and spine. OF the ske-
Jeton there still remain the bones of the four extremities, the
spelvis, and the shoulder. But it would be tiresome and useless,

4, Observations on the Natural H story

say the authors, to give minute demonstrations of these; their
figure, size, and position, are delineated of their natural size in
Plate VI. Fig. 2, m which also the bones previously described
are exhibited.

The authors having previously remarked that the bones of
the proteus are less rigid than those of the aquatic salamander,
proceed next to point out a few differences of form in the skele-
tons of these two animals. At first they appear very similar,
but many points of dissimilarity occur on closer imspection.
Thus, the transverse processes of the vertebrae in the two ani-
mals differ in relative size and form, as do also the costulz or
riblets that spring from them. In the salamander, the cartilages
of the shoulder are large enough to extend over the breast, and
perform the office of a sternum: in the proteus, on the con-
trary, they do not touch. Again, the pelvis, m the proteus, is
attached by one extremity to the transverse processes of the
thirty-first vertebra, and with the other end contributes, with
the os pubis, to form the cotyloid cavity: in the salamander,
the ileum is not immediately attached to the spme, but only by
the intermedium of a little bone: and hence, in these reptiles,
the whole pelvis is moveable. In the salamander again, there
are only two vertebrae which form the sacrum; in the proteus
there are three. Other differences might be noted in the bones
of the tail and paws; but not to go nto farther details of this
sort, the authors prefer giving the results of their observations
on the respective locomotive powers of these animals.

2. Of the Movements of the Proteus in Water and on Land,
compared with those of other Animals. ;

Whoever shall attend to the particular structure of the ver-
tebrae in the proteus, and their reciprocal connection, will easily
perceive that the lateral movements of the head towards the
trunk, and the lateral bendings of the trunk itself, will be some-
what limited in its superior part, where the articular apophyses
form two planes inclined and converging in one and the same
line: but as these processes gradually diminish im size, the ca-
pacity ef moving laterally will be greater as we descend, and
greatest of all when it reaches towards the eighth caudal verte-
bra, since there the processes entirely disappear. In the sala-

and Structure of the Proteus Anguinus. 5

mander, the lateral movements of the trunk will be still more
limited than in the proteus, by reason that the ridge, formed
by the canal of the spinal cord, will impede the free motion of
the articular processes on one another. We have observed at-
tentively, continue the authors, and compared the movements
and mode of progression of the proteus, and of the salamander
and its larva, both in water and out of it; and have had the
- satisfaction of seeing that these movements, as well in swimming
as in walking, correspond with the consequences previously de-
duced from a simple examination of the skeleton. A few of
these observations they then proceed to relate.

The protei which, with this view, they submitted to observa-
tion, had already lived many months in earthen vessels, the
bottoms of which were flat and of the figure of a parallelogram.
To these vessels were adapted lids formed of many pieces; but
so fitted together that the light was unable to penetrate, and
the animals consequently lived always in complete darkness.
When it became necessary to change the water, a portion of
the lid was removed, and then the animal, by moving to the
opposite side of the vessel, was able to continue in obscurity.

It has been already observed, that the proteus, in ordinary
circumstances, remains as if immoveable at the bottom of the
vessel; but at once begins to move with more or less rapidity
as the light is let in upon him. Of this fact, the authors availed
themselves in their observations on the movements of these ani-
mals. Having first discovered in what part of the vessel the
animal reposed, the piece of lid above him was gently raised, so
as to expose him to light. As soon as he felt its influence, he
instantly began to move and withdraw himself to that part of
the vessel which was still dark. In making this movement,
however, he did not always employ the same kind of motion.
Sometimes he drew up the lower part of the trunk and the tail,
or rather gathered himself up in the manner of a serpent. In
doing this, he made use only ef the muscles of the spme, and
not of those of the hind limbs, which, durimg this action, re-
mained quite at ease, and followed the trunk as if they had been
paralytic. “When the body was thus gathered up, and formed
into a serpentine line, the animal thrust the hind limbs to the
bottom of the vessel; then stretching forward the whole trunk,

6 Observations on the Natural History

he began, at the same time, to move, one after another, the fore-
limbs; so that, making use of the hind limbs as serpents use the
ventral scales, and employing the fore-limbs to sustain the head
and chest, the animal proceeded slowly along, crawling in part,
and in part moving like a biped animal.

Sometimes, again, the proteus sought to avoid the light by
making use only of the limbs, keeping then the body and tail in
a right line, and moving the limbs alternately as quadrupeds do
when they move by steps. At other times, he moved ina way
both singular and amusing; for gliding along so as to graze the
bottom of the vessel, and supporting himself on the fore-limbs,
he kept the hind ones applied to the sides of the trunk ; so that
the body, from the shoulders backward, was entirely suspended
-and gliding; and from the shoulders forward, was sustained on
the fore-limbs, which moved alternately, and with much quick-
ness, along the bottom of the vessel. ‘This mode of progression
was a mixture of the gliding of fishes and the walking of biped
animals. A fourth mode im which the animal sought escape
from the light was by suddenly betaking himself to swimming.
This always occurred when the whole vessel was at once un-
covered. At the same time, he glided rapidly over the sides of
the vessel, and made attempts to escape out of the water, im or-
der to withdraw himself from the light, which so greatly dis-
tressed him. Whilst the proteus thus glides along the sides of
the vessel, his motions resemble those of the lamprey, and, like
that fish, he drops to the bottom as soon as he ceases to move.
‘The lamprey, however, aids his motions by the incurvations of
the trunk, while the proteus glides along chiefly by the use of
the tail, which moves to either side with great facility and
quickness, exactly as occurs to fishes. ‘This difference arises
from the spine of the lamprey being wholly cartilaginous, and
therefore equally flexible in every part; but in the proteus, the
spine is entirely osseous, and incapable of any considerable de-
gree of flexion, except towards the tail.

Beside the resemblance above noticed in the motions of the
Jamprey and proteus, it is observed that the latter animal, when
he swims, makes no use of the feet, either to start him in the
first movement, nor afterwards to sustain his equilibrium. His
Iimbs continue applied always to the sides of the trunk, and may

and Structure of the Proteus Anguinus. 7

be compared to the four oars of a boat, floating freely in the
water, but attaehed by leathern loops to the sides: if in this
state the boat be urged forward by the winds, the cars are soon
forced back by the water and laid alongside the vessel. From
not making use of their limbs in thus gliding through the water,
it sometimes happens, that these animals, in the act of changing
their direction, roll over, and afterwards right themselves, as
soon as they have got on their new course. The same thing
occurs to lampreys, which, in gliding along, sometimes roll over :
and when they descend to the bottom, if they wish to remain at
rest, and preserve a rectilinear position, they are constrained to
attach themselves to some solid substance, by making use of their
mouth, which adheres on the principle of suction, else, having
neither feet nor fins to maintain themselves straight, they are
obliged to le down on their sides. These facts seem to shew
that the principal use of the fins im fishes is to maintain the
body in equilibrio, as the learned M. Cuvier has observed.

With respect to the movements of the adult salamander in
water, as compared with those of the proteus, the authors ob-
serve that he is less agile. This may arise from various causes,
but principally from the form of the tail, which is not only of
less size, but is less adapted for swimming. The larve also of
the salamander are less agile than the proteus, but in that state
they swim with more facility than afterwards. This probably
arises from the tail in the larva state being proportionally larger,
and also from the larva possessing a lower specific gravity than
the adult animal, except when the latter has recently emerged
from his winter torpor. That the larve have a lower specific
gravity than the adult salamanders, is inferred. from the fact
that they are able to sustain themselves in water, at whatever
height they please, only by moving, from time to time, ina slight
degree, their claws and tail. It is beautiful to see them continue
thus suspended, and as if balanced, on their four limbs in the
water, like a bird librating in the air: and afterwards, by strik-
ing the water behind them, and by a slight movement of the
tail, transfer themselves from one place to another.

The authors subjoin a few remarks on the movements:of these-
several animals on land. Salamanders move from place to place
only by a simple motion of the limbs. ‘They have neither the

8 Observations on the Natural Histony

ventral scales, nor the long ribs of the serpent, which are consi-
dered to serve as organs of locomotion. Their trunk stands
supported on the four limbs, and does not touch the ground but
occasionally, and then only when they move by steps; so that
they move on land with the gait common to all quadrupeds. As
the larva approaches the period of transformation, his move-
_ ments resemble those of the adult salamander ; but when young,
the limbs are so slender and weak, as to be unable to sustain the
trunk. Ata later period, when taken out of the water, he is
able to move a little to the right and left with the anterior part
of the body ; but with the posterior part, he remains as if fixed
to the surface on which he stands.

Not dissimilar to the larvae above mentioned are the protei,
‘with regard to the capacity of progression out of water. They
possess not the incurvations of the trunk, by which they would
be enabled to crawl; nor do their four limbs serve them for
creeping, nor for moving like quadrupeds. If they bend to the
right or left, the entire body forms but a single curve; and on
resuming a straight line, the body is found always in the same
place. Itis true, that, sometimes by pushing with the hind-
limbs forcibly against the ground, and stretching forward the
trunk, they are able to move a little in advance ; but this is done
with the greatest difficulty, from the circumstance that their
body being smeared with a viscid mucus, adheres to the surface
on which éties attempt to move.

It thus appears, that, in water, the proteus has the suede
and surprising faculty of moving himself in the manner of qua-
drupeds, of serpents and of fishes ; and that he adopts now one
kind of movement and now another, according as his necessities
urge him to move with greater or less rapidity. His whole
structure seems to destine him to live continually in water, and
unfits him for the life of a land animal; but the aquatic sala-
mander has limbs sufficiently strong to move on land ; and the
authors have been assured by men who are employed in fishing
in the streams they inhabit, that at certain seasons they go on
land.

We find no particular account of the muscular system, but
the authors proceed next to treat,

and Structure of the Proteus Ang uinus. 9

3. Of the Organs of Digestion.

The tongue of the Proteus through its greater part, is fleshy,
and is free both at its apex and on its edges ; it is supported, as
usual, by the os hyoides. The passage from the fauces to the
stomach is very short; nor is it easy to fix the place where the
esophagus terminates. The stomach proceeds in a strait line,
is only a little larger than the intestines; and, on a first view,
appears like a portion of them. ‘The membrane that covers the
fauces, is continued into the stomach and intestines, forming
various rugé@ or longitudinal plaits, more than six or seven in
number. These plaits begin where the cesophagus commen-
ces; they gradually disappear towards the middle of the stomach,
and become again conspicuous as they approach the pylorus,
where they are more raised than in any other part of the canal.

The intestines are enveloped in a duplicature of peritoneum,
which is continued through their whole length. They are
formed of very fine and transparent tunics, and make several
convolutions im their course. Their size is nearly uniform
throughout. In protei recently taken in summer, they always
contained foeces; but in winter, neither the stomach nor intes-
tines contained any remnants of food. The internal organs of
generation in the male and female, as well as the kidneys, open
into the intestines, near the anus.

The liver begins and terminates in a point; it isso long, that
it extends through two thirds of the abdomen. In its left mar-

_gin there are some fissures ; and in one deeper than the rest the
gall-bladder is lodged. The colour of this viscus is reddish, ap-
proaching to that of rust of iron; and its surface is every where
speckled with small blackish spots. Its figure is convex below,
and concave above towards the spine.

The spleen is a finger’s breadth in length, and is placed by
the side of the stomach, to which it is attached by vasa brevia
and a doubling of the peritoneum.

The pancreas is only half the length of the spleen; and is
attached to that portion of the alimentary canal which is imme-
diately below the stomach, and called dwodenwm.

On the whole, the organs of digestion, as well primary as se-
condary, much resemble those of the aquatic salamander. In
these last, however, the stomach is somewhat curved, and placed

B

10 Observations on the Natural History

a little transversely ; and the intestines are evidently divisible
into large and small, and are, moreover, furnished with fatty
appendages. A general idea of the relative size and position
of these several viscera, is exhibited in Plate VII. Fig. 1.

4. Of certain Opinions of MM. Schreibers and Cuvier, re-
garding the length and figure of the Alimentary Canal.

Before quitting these organs, it is proper to notice a difference
of opinion between MM. Schreibers and Cuvier, with respect
_ to the length and figure of the alimentary canal. ‘The former
exhibits figures, from which we learn that the intestines, before
they open externally, make several convolutions ; the latter, on
the contrary, affirms, that the alimentary canal proceeds almost
in a straight line from the mouth to the anus. A simple state-
ment of the appearances exhibited by the several protei examin-
ed by the authors, and their observations thereon, will account
for this disparity of opinion, and explain its cause.

The three first protei they dissected, had been preserved
about seven months in ardent spirits, (brandy,) and in all the
three the intestines were convoluted. They then killed and
injected a living proteus, and immediately afterwards opened the
abdomen, and found the intestines, as in the former examples, to
possess a convoluted form. The following summer they re-
ceived eight other protei, five of which had died on the journey,
and were put into spirits, and the three others arrived in a very
lively condition. They proceeded at once to anatomise the five
dead ones ; and found in all of them the intestinal canal almost
strait, as described by Cuvier. Perplexed by these opposite
appearances, they formed several conjectures as to their cause ;
but these afforded little satisfaction to the mind, when, in the
midst of their doubts, accident at length enabled them to dis-
cover the truth. In the succeeding autumn, they obtained a
fresh supply of living protei, similar in all respects to those
which had arrived in May One of these was killed and inject-
ed; and afterwards, on opening the abdomen, the intestines ap-
peared convoluted, and similar in length to those of the protei
first examined. These facts being observed and recorded, the
animal was put into spirits for a second examination at a future

PLATE Xt.
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and Structure of the Proteus Anguinus. ii

period. In six or seven days, he was taken out of the spirits to
examine the injected vessels; when casting their eyes on the intes-
‘tines, the authors observed, not without surprise, that the alimen-
tary canal, which, afew days before, was convoluted, soft and
transparent, had now become not only opake, but so much short-
ened, that had they wished to describe it, they might have said
in the language of Cuvier, ‘‘ qw’al alloit presque en ligne droite
un bout a Cautre.” This fact, though at first it excited surprise,
brought with it much satisfaction, since it was easy to compre-
hend, that the shortening of the alimentary canal was owing to
the animal having been placed in ardent spirits, while the intes-
tines yet retained their irritability. Of this opmion they after-
wards obtained proofs in various ways; and, in particular, ha-
‘ving, on one occasion, opened the abdomen of a living proteus
for another purpose, they observed the intestines to be at first
convoluted and transparent; but under exposure to the air,
these organs gradually contracted to sucha degree, that, at last,
under the eye, they became knotty and opake, and continued to
wrinkle and shorten more and more; so that, after the death of
the animal, (which occurred in about half an hour,) they were
brought nearly to a strait lme. Instead of spirits, the animal,
in this its dissected state, was placed in water. On visiting it the
next day, the alimentary canal was found so much relaxed, as
to have recovered its former length ; and when the animal, now
destitute of irritability, was placed in spirits, its intestines main-
tained their convoluted form, and did not visibly shorten after-
wards but a very few lines. From these and other facts, the
‘authors infer with confidence, that the alimentary canal of the
proteus is always naturally convoluted; and that when it is
seen to proceed in a strait line, it has suffered contraction from
the action of ardent spirits, or some other agent upon it, while
still possessed of irritability.

Experiments similar to the feregomg were ded on the intes-
tines of the salamander and frog. These animals resist death
longer than the proteus, and may be considered to possess great-
er irritability ; but in them the contraction of the intestines was
not observed to equal, in any degree, that of the proteus, ari-

sing, probably, from some difference of structure. These obser-
BA

12 Observations on the Natural History

vations, say the authors, not only illustrate certain facts reward-
ing the proteus, but may apologise for those learned writers,
who, from not having had the opportuntity of dissecting this
animal when recently dead, have deviated, in their anatomical
descriptions, some little from the truth.

5. Of the Organs of Circulation.

The heart of the proteus is lodged in that triangular space
which is formed by the branchial arches. Its situation and size may
be seen in Plate VII. Fig. 1. Its structure is simple, consisting,
like that of the frog, of one auricle and one ventricle. In figure,
also, it resembles the heart of the frog, but is somewhat smaller
in proportion. Its auricle is placed forward, and over the ven-
tricle ; is shghtly toothed on its margins ; and to the eye seems
as large as the ventricle itself.

From the base of the heart on the right side, springs a very
short canal, which proceeds straight forward ; but before it gets
beyond the auricle, by which it is covered, it expands into a
bulbous form. This short canal, the only one that goes out from
the heart, is of a soft fibrous texture, similar to that of the heart
itself. The bulbous part, on the contrary, possesses great
strength, and is opake and tendinous. Hence it is, that whe-
ther it be empty or full cf blood, it exhibits always a whitish
pearly colour, different entirely from the other parts of the ves-
sels, which, when full of blood, appear of a reddish or russet
hue.

From this bulb proceed two large arteries, which, almost imme-
diately on quitting it, separate from each other, and are direct-
ed, on either side, towards the branchial arches. These two ar-
teries, for greater clearness and convenience of description, are
called the two primary trunks; but the authors will speak
only of one, since what is said of one will apply equally to the
other.

The primary trunk, then, of the right side, very soon after quit-
ting its fellow, gives off a branch which runs under the first arch
through its whole length, where it sends off two arteries, one to
the first gill, and the other to the muscles of the os hyoides ; af-
terwards, abandoning the arch, and turning upward and inward,
it goes to the roof of the occiput. This first branch from the

and Structure of the Proteus Anguinus. 13

primary trunk, beside its office of conveying blood to the gills,
corresponds, in other respects, to the common carotid.

The other or second branch of the primary trunk, is conduct-
ed beneath the second or middle arch ; and having reached the
place where the third arch joins with the second, it sends off an
artery which runs along the margin of the third arch, and goes
to form the third gill. The main portion of this second branch
then proceeds along the middle arch ; and a little before reach-
ing its posterior extremity, sends another artery for the forma-
tion of the middie gill. After this, turning upward and inward,
it goes for a short way towards the occiput; and getting near
the second vertebra, it bends backward and downward by the
side of the spe; towards the fourth vertebr a, it meets, under
the spine, with its fellow from the opposite side, and both then
uniting, form together the aorta descendens, which is continued
towards the tail. It is not necessary to follow the aorta through
all the branches it gives off in its descent. We must not, how-
ever, omit to mention, that this second or chief branch of the
primary trunk, before it bends backward and downward,
sends off three branches, and makes also an anastomosis with
the common carotid. Of the three branches, the first is sent
to the air-bladder, and to the ovaries in the female, and testicle
in the male. The second is distributed to the parts about the
temple ; and the third is the vertebral artery, which, after giving
off some twigs to the occiput, enters the canal of the vertebre,
and descends towards the tail. This description of the circulat-
ing system, is accurately represented in Plate VII. Fig. 3

Let us next follow the course of the branchial arteries, destin-
ed, as we have seen, to form the gills. Immediately on quitting
the branchial arches, they are continued out of the head; and
scarcely have they gone out, than they divide mto many
branches, which, m their turn, subdivide into others, and these,
again, mto minute ramifications, in such a manner, that the three
gills resemble three little plantules, rooted to the sides of the oc-
ciput, and furnished with many minute leaflets. The reason
why the structure of the gills is so similar to that of a leaf, is,
that the fine skin which lines the fauces, invests the arteries as
they traverse the arches ; and, following them externally, clothes
them as they divide: but as they approach their last divisions,

14 Observations on the Natural History

there this skin, instead of surrounding them individually, as it
had done in the larger branches, expands into a membrane,
which comprises between its two surfaces all the ultimate ramifi-
cations into which each lesser branch has spread. A good idea
of this foliated structure may be obtained, by inspecting Fig. 4.
Plate VII., in which a portion of one of the leaflets is represented,
and where the blood of the branchial artery, of a dark colour, is
seen moving round the margin of the leaflet. In its course, it con-
tinually passes off transversely through the net-work of vessels

-that forms the expanded portion of the leaflet; and, losing in
its progress its dark colour, and acquiring a florid hue, it is
finally collected from the several leaflets into the branchial yem
at the root of the gill®. .

Scarcely have these branchial veins reached the roots of the
gills, than they separate from their accompanying arteries, and
entering between the extreme points of the arches, proceed su-
perficially towards the top of the spine. The vein of the first
gill enters between the first and middle arches, and soon after
pours its blood into the first branch of the primary trunk, or
that named Common Carotid. The two other veins, on the
contrary, in re-entering the head, pass between the middle and
third arches: Afterwards, they unite into a single canal; and
thus reunited, they deliver their blocd into the second branch
of the primary trunk, a little before that vessel sends off its
branch to the air-bladder and sexual organs. This distribu-
tion of vessels conveying dark blood to the gills, and of those
which carry back florid blood from those organs, is repre-
sented in Fig. 3., as above. Of the subsequent distribution of

* The authors remark, that the structure of these leaflets of the gills is visi-
ble only in dead protez, especially in those which, from having been placed in
spirits, have lost their transparency. In the living animal, while remaining in
water, they can be seen but with the greatest difficulty ; and then only when very
turgid with blood. The reason is, that the membranous expansions, between
which the ultimate ramifications of the arteries and veins are comprised, are so
exceedingly fine and transparent that an inexperienced eye is unable to perceive
them ; and an observer, in such circumstances, being unable to use a high magni-
fying power, and seeing only the vessels which bound the margins of the leaflets,
have supposed the gills to be formed rather like a dissected than entire leaf, or re-
sembling somewhat the horn of a stag.

and Structure of the Protews Anguinus. 15

the blood by the vessels given off from the aorta, it is unneces-
sary to say more; but of the return of this blood to the heart
by the veins, it is proper to take some notice.

There are three principal veins which reconvey the blood from
the different parts of the body to the heart; two corresponding
to the jugulars, and the third to the ascending vena cava. The
two former, after receiving the blood which returns from the
head, pour it into the cava, where that vein is so dilated as
to form a sort of sinus. Into the cava, also, at different parts,
is poured all the blood returned from the trunk. Thus two
Jarge veins which ascend the spine on each side of the aorta,
‘and receive the blood of the dersal veins in their progress,
enter the cava much below the middle of the trunk. The blood
of the air-bladder and organs of generation is poured, by a
single vein, into the cava about the middle of the kidney. ‘The
vein which collects the blood from the intestines, arises near’ the
termination of the alimentary canal ; and proceeding between the
expanded portions of the peritonzeum that form the mesentery,
gains the neighbourhood of the stomach : there its trunk, which
may be called the vena porta, is spread entirely through the
concave surface of the liver. After circulating through that
viscus, the blood is again collected into one vein, which, travers-
ing the edge of the liver, pours its blood into the cava at the
point where that vessel itself quits the liver to continue its course
to the auricle.

6. Of the Organs of Respiration.

In the preceding chapter on the organs of circulation, the
authors have described, with all the accuracy they were able, the
course of the branchial arteries and veins to and from the gills,
which might be considered as including a description of the res-
piratory organs; but as the proteus anguinus, besides being fur-
nished with gills, is provided also with two air-bladders, which,
from a resemblance to the lungs of the aquatic salamander, have
been regarded as two real lungs, it is necessary to give a more
particular description of those two organs.
In the bottom of the fauces, and exactly in the middle of
that space which lies between the branchial apertures which
communicate with the gills of each side respectively, there is a

16 Observations on the Natural History

small cleft or chink, the margins of which do not rise above the
surface, nor possess a cartilaginous structure. This very small
chink or glottis, as it may be called, communicates with a very
short canal, which proceeds backwards above the heart, between
the pericardium and pharynx. This canal exteriorly, and on
the side next the heart, is furnished with two very fine muscu-
lar expansions, the fibres of which springing from the median
line of the canal itself, are disposed like the beard of a pen, and
direeted back towards the branchial arches. The office of this
very subtile muscular substance is, doubtless, that of dilating the
canal, and opening the glottis. The canal itself, before getting
beyond the heart, opens, by a semilunar aperture, which has car-
tilaginous margins, into a large conical cavity, Plate VII. Fig. 2.
From this funnel-shaped cavity, are continued two membranous
canals, which, keeping the stomach between them, descend towards
the tail: but before reaching the lower-third of the trunk, they
begin to dilate, and by degrees expand, so as to acquire the form
_of two small flasks; the left descending a little lower than the
right. These two canals are attached to the spine, by duplica-
_tures of the peritoneum, in which, through their whole length,
they are involved. The two little flasks or bladders have no
cells nor partitions internally, but are perfectly smooth mem-
branes. Were it possible to dilate the two canals to the size of
the bladders in which they terminate, these organs would then
acquire very exactly the form of the lungs of the salamander.
The two bladders are situated one on each side of the abdomen ;
that of the left side is represented in Plate VII. Fig. I., and also
the narrow canal leading to it. In protei that have been some
time in spirits, the canals become entirely closed and quite imper-
vious to air; but in those recently dead, the bladders are easily
dilated by air blown through the canals.

The authors having observed, that, when a living frog or sala-
mander is laid on his back, the abdomen then opened, and its
walls fastened back, the lungs, durmg the struggles the animal
makes, sometimes dilate and contract for a certain time, were
desirous of ascertaining, by a similar experiment, if the small
portion of air which the proteus takes into the mouth found its
way into the two little bladders above described. A proteus

and Structure of the Proteus Anguinus. 1%

was, therefore, fastened on a board, the abdomen was opened,
and its walls kept asunder by means of pins, in order to observe:
what would happen to the air-bladders. In a few mimutes the
animal began to take air into the mouth, and afterwards panted
with a quickness always increasing for a quarter of an hour;
after which his pantings became weaker, and at the end of half
an hour he died. While the proteus was thus agitated and
panting, they watched attentively the two air-bladders, but did
not see in them the smallest movement, which could indicate
the entrance of air. They saw, however, that these bladders
gradually contracted from the action of the external air; and at
length became corrugated to such a degree, as to resemble in
figure two fleshy bodies, of the form and size of two grains
of wheat. The air which entered the mouth escaped entirely
by the branchial apertures, forming mostly minute bubbles,
which, for some time, remained attached to the edges of those
apertures.

7. Of the Organs of Generation.

The authors regret, that, under this head, their observations
are not so complete as they could have wished; and that some
points relating to it are still enveloped in obscurity.

Of the five protei dissected in the month of May, as before
stated, there were two in whom the sexual organs were so fully
developed, that no doubt could remain of the one being a male,
and the other a female. In themale, the testes were attached to the
air-bladder. To the eye they appeared to be a congeries of most
minute globules; but when examined under the microscope,
their substance was nothing else than a mass of most minute
vessels, disposed longitudinally, and extending in a serpentine
line from one end of the testicle to the other. Towards the
posterior part of the organ, where it had somewhat of a pyri-
- form figure, these minute vessels enlarged and separated a little
from ecah other. Continuing the examination, they observed,
towards the extremity of the alimentary canal, a circular ring,
evidently formed by the internal tunic of the intestine, from
which proceeded many longitudinal threads, which extended to
the margin of the anus: but nothing was seen like a receptacle
for semen, nor penis, nor vasa defvrentia. A vessel seemed to
extend from the posterior part of the testicle, and open into the

18 Observations on the Natural H astory

mtestine; but whether this be the excretory duct of the testicle
could not be determined. From an observation of M. Schrei-
ber, the authors conjecture, that the testes of the proteus are
subject to some remarkable changes with the increase of years,
like those of the aquatic salamander, in which the testicle at first
is formed of one spherical body ; afterwards of two, and subse-
quently of three ; and not of two only, as M. Cuvier has stated.
The position and form of this organ may be seen in Piget,
Plate VII. (g).

The ovaria of the female are situated under the kidneys, and by
the side of the rectum. They are enveloped in peritoneum, and
have connection both with the spine and air-bladder. In protei
recently dead, and not yet put in spirits, the ovaries appear an
oblong mass of albumen, in which are suspended a vast number
of minute ova. The oviducts do not commence near the heart,
as in frogs and salamanders, but towards the anterior third of
the trunk. They descend by the side of the spine, along the
exterior margins of the kidneys ; and having reached the poste-
rior extremity of the kidneys, they approximate and terminate
into the intestine by a common aperture, a small distance from
the anus. In the proteus dissected by M. Cuvier, he describes
*« les oviductus tres-longs, et faisant beaucoup de festons, com-
me ceux de la salamandre ;” but the authors have not met with
such appearances. In protei preserved in spirits, the oviducts
were always found straight; and in those recently dead they
were much longer, but did net form those twistings and wind-
ings which the ducts of the salamander make before they enter
the intestine. See Plate VI. Fig. 3.

8. Of the Organs of Secretion.

The kidneys of the proteus are so long as to occupy the —
lower half of the trunk. In structure, they much resemble those
of the salamander ; but in their anterior part are two curvatures
or sinuses, i which the two air-bladders are respectively lodged.
The ureters are much convoluted anteriorly, but extend ma
straight line towards the posterior half of the organs, where they
gradually approach each other, and finally unite together at their
termination by one common aperture in the intestine. Tt must
also be remarked, that, in the male proteus, as in the salaman-
der, the ureters commence high up on the spine, and descend

and Structure of the Proteus Anguinus. 19

afterwards in a night dine, till they reach the anterior point of
the kidneys, where they make many twistings, and pursue a ser-
pentine course, till they arrive at the lower half of those organs.
In the females of these reptiles, on the contrary, the ureters are
less convoluted, and do not commence at any distance from the
kidneys; whence, it is probable, that from this difference of
form, the ureters of the male may exercise some other office be-
sides that of conveying the urme. In Fig. 3. Plate VI., the
kidney of a female may be seen.

But though the kidneys and ureters in the proteus and
salamander bear so near a resemblance, the form of the uri-
nary bladder in the two animals is quite different. In the
salamander, this organ is shert, and its fundus bifid. In
the proteus it 1s long, and has a simple fundus; so that it
resembles more an appendix cceci of the intestine, than an
urinary bladder. It is annexed to the intestine in a point
diametrically opposite to that into which the two ureters are in-
serted-; in other words, it is inserted into the wall of the intes-
tine that looks downward, while the ureters terminate in the wall
that regards the spine. In the proteus, therefore, as m other
reptiles of the same family (Batraciens,) the ureters do not ter-
minate in the bladder, but discharge themselves directly into the
intestine, at a point opposed to the bladder. .This fact has led
many, and among others Townson and Schreibers, to doubt if
the organ named the urinary-bladder, be, in frogs and salaman-
ders, a real receptacle for the secretion of the kidneys, or destin.
ed to some other office. ‘Townson, supposing the urine poured
into the intestine by the ureters to be at once discharged with
the feces, suggests the idea, that the bladder above menticned
may be regarded rather as a reservoir of water absorbed from
without, and destined to some particular use in the animal eco-
nomy. His words are, “ Cum nunquam bibant hee animalia,
opus tamen sit ils tantopere aqua, probabile mihi videtur, aquam
cute absorptam, aut ejus partem induci in vesicam, tanquam
im vas quod eam servet; atque inde distribui, prout econom a
animalis requirat, eodem fere modo, quo fluidum receptum
in ventriculum aliorum animalium inde distribuitur *.” That
the skin of frogs absorbs water, seems demonstrated by the re-

“ See Townson, Observationes Physiologice de Amphibiis, &c.

20 Observations on the Natural H istory

cent experiments of Dr Edwards ; but that the water so absorb-
ed is conveyed into the aforesaid biadder is merely a conjecture ;
and, as appears to the authors, wholly without foundation. But
if we reject Townson’s conjecture, what must we think of the
fluid with which the bladder, both im frogs and salamanders,
is so frequently filled? If it come not from the kidney, from
what other gland or organ can it proceed? Is it secreted by the
bladder itself? This supposition is not probable ; for the walls
of the bladder are not sufficiently furnished with vessels to se-
crete so great a quantity of fluid. From some experiments not
yet published, the authors are disposed to regard this organ as
a true receptacle of urine.

9. Of the Organs of Sense.

The brain of the proteus very much resembles that of the sa-
Jamander, especially when in the larva state. The two hemis-
pheres are nearly cylindrical ; the lateral ventricles are large, and
in their posterior extremity he the corpora striata. 'There is al-
so a third ventricle, and two optic thalami, very small, and of an
oblong form. The carotid artery, on entering the cranium,
makes a twist around the aperture, and sends off the opthalmic
artery, which is continued, between the cranium and hemisphere,
to the eye: the principal trunk of this vessel then proceeds be-!
neath the brain, and, spreading into beautiful ramifications, is
distributed to the two hemispheres, &c. See Fig. 4. Plate VI.

The eyes of this animal are situated, and we might say buried,
between the anterior extremity of the masseter muscles, which
go to be inserted in the lower jaw, and the posterior extremity
of the canal of the nostrils. ‘They are inconceivably small, and
are placed, not in an orbit formed by bone, but in a web or
tissue, formed of venous and nervous ramifications. No muscle
nor optic nerve has yet been discovered ; but on raising the he-
mispheres very gently, a very subtile nerve, similar to the fine
thread of a spider, seemed to go to the foramen, through
which passed the ophthalmic artery, as seen in Fig. 4. The
crystalline humour is large in proportion to the other parts,
and has a spherical figure: the sclerotica is not white, but
blackish ; of the other parts we dare not say more; for, from
their extréme minuteness, it is difficult to speak of them with
precision.

and Structure of the Proteus A nguimus. Q1

The organ of hearing in the proteus is very simple. It has
neither membrane nor cavity of the tympanum; but consists
only of a large cavity formed in the bones of the cranium, in
which is seen the little sac containing the ossicula or small bones :
this cavity is aiso furnished with a fenestra ovalis, closed by a
bony plate. On raising the little sac the semicircular membran
ous canals appeared to come into view, but of this the authors
do not speak with confidence. This organ, as seen by them, is
represented in Fig. 4., as above.

The organ of pet in the proteus differs pagrceipe in structure
from that “of the salamander, and the other animals of the same
family ; and if we are entitled to infer the perfection of the sense
from the structure of the organ, the proteus angwinus, im this
respect, will surpass all other known reptiles. The external
aperture of the nostrils is exceedingly small, and of a triangular
form; its position is represented in the profile view, Plate VI.
Fig. 5., and corresponds internally with a canal that is soft and
pulpy through its whole length. The olfactory nerves are rather
large; these nerves, after passing by the bulbs of the eyes, go
out of the cranium, and divide and ramify on the soft substance
that lines the nostrils. If with a needle the canal of the nostrils
be broken down, and its substance removed, preserving at the
same time the nervous filaments distributed upon it, the olfac-
tory nerve is then resolved into a pencil of filaments, as deline-
ated in Fig. 4.

Conclusion.

Having thus terminated the anatomical description of the
Proteus Anguinus, the authors proceed to examine the two
following questions; firstly, Whether it be true, as many
believe, that this reptile can respire, at the same time, by
gills and by lungs? Secondly, Uf the Strena lacertina is to be
regarded asa larva or a perfect animal? ‘To determine these
questions, it will be necessary to compare the branchial struc-
ture, the organs of circulation, and the supposed lungs of the
proteus, with the corresponding parts in the sirena and in the
lurve of the salamander and of frogs.

With respect to the branchial structure, there is a remark-
able difference, not only as to form, but to texture, between the
arches of the proteus, and those of the siren and larvae above
mentioned. In the siren and larve, the branchial arches are

92 Observations on the Natural History

four on each side, and their margins are furnished with small
poimts,—in the proteus, there are but three on each side, and |
these are smooth. The arches of the proteus have an osseous
structure,—those of the siren and larve are cartilaginous.
This difference did not escape M. Cuvier, who, speaking of the
proteus, says, “l'appareil osseux qui porte les branchies, est
beaucoup plus dur que ne l’avons trouvé dans la sirenc, et dans
Paxolotl:” and in his anatomical description of the latter ani-
mal, he farther says, “ Pappareil qui supporte les branchies a
de grands rapports avec celui de la sirene, et je crois que, lors
de la metamorphose, il en reste une partie pour former los
hyoide de la salamandre *.” Now, if the branchial arches of
the siren be, as M. Cuvier asserts, entirely cartilagmous, al-
though the cranium, the lower jaw, and the vertebra be per-
fectly ossified ; and if these arches, both in form and number,
be similar to those of the avolotl, which M. Cuvier himself
regards as a larva,—may it not be presumed that the former
animal is a larva also? If, farther, the branchial arches of the
proteus, which is a perfect animal, be osseous, and entirely dif-
ferent from those of the siren and all the larvee hitherto known,
have we not in these facts the strongest reasons for regarding
the siren as an imperfect animal, and, therefore, essentially dif-
ferent from the proteus ?

With regard, next, to the organs of circulation, there are, m
the larvee of the frog and salamander, as many arteries given

* The authors here observe, that they have not themselves had an opportu-
nity of anatomising the sirena lacertina; and, therefore, with regard to its inter-
nal structure, they trust entirely to the descriptions of M. Cuvier, who has writ-
ten largely upon it.

It may not be out of place to add, that, in the new arrangement of M. Cu-
vier, the Proteus anguinus stands in the class Reptiles,—order Batraciens,—
genus (containing as yet only one species,) Proteus. Besides internal lungs, it
bears externally, like the larva of the salamander, three gills on each side of the
neck, which it appears to retain through life.

The Strena lacertina occupies the same class and order, and is another genus
consisting only of one species. It is said, like the proteus, to retain through its
whole life, three gills on each side the neck, and to possess, at the same time,
lungs internally.

In the same class and order is placed the Axolotl of the Mexicans, or Sirena
pisciformis of Shaw. It belongs to the genus Salamandra, of which it is a spe-
cies. Some allege that it also always retains its gills.—Vide Le Regne Animal,

tom. ii. p. 101,—102.—Taans..

and Structure of the Proteus Anguinus. 23

off on each side by the trunk that springs from the heart, as
there are branchial arches, viz. four. In the siren and axolotl,
(which have also eight branchial arches,) M. Cuvier speaks
only of six arteries, three on each side, going to the gills; but
as, by the aid of injections, we have found, say the authors, that,
in the larvee above named, there are eight vessels, and that the
artery which runs along the interior arch of each side, and
which M. Cuvier has not seen, is that which in process of time
becomes the pulmonary artery, so, guided by analogy, we hold
it for certain, that, as the siren is furnished with eight bran-
chial arches entirely similar to those of the other larvae, there
are also eight arteries, four on each side, corresponding to
them. And, proceeding on this opmion, we may remark a
striking difference in the circulating system of the siren and
proteus, since the artery, properly called Pulmonary, which is
found in the siren and larvee above mentioned, does not exist m
the proteus. Doubtless in the proteus, the air-bladder, like
every other part of the body, is duly supplied with blood; but
the blood sent to it is furnished by an artery coming off, on each
side, from one of the aortic trunks, and which artery, descending
along the canal of ihe bladder, gives to it a branch, and is then
continued to the ovary or testicle in each sex respectively.

Besides these differences im the arterial, there are cthers in
the venous system ; for the vessel which returns the blood from
the air-bladder of the proteus, does not empty itself directly
into the cava or the auricle, as is observed in other reptiles 5,
but into the vein which carries back the blood from the organs
of generation, which itself enters the cava above the middle of
the kidney ; hence in the proteus, not only the true pulmonary .
artery, but the vein also, is wanting. This anatomical fact, ascer-
tained by repeated injections, might alone be sufiicient to de-
monstrate, that the two air-bladders with which the proteus is
furnished are not true lungs: but as some, perhaps, may not
yield to the force of these arguments, we shall continue the-
comparison, especially as applied to the organs of respiration.

In the larvee of the frog and salamander, the trachea opens.
directly into the lungs. These organs have the form of two.
sacs, and, from being longer than the trunk, cannot be extend-
ed in a straight line through it, but at the lower end are folded.

24 Observations on the Natural History

a little from one side of the abdomen to the other. So, in the
siren, we see the trachea to open directly into the lungs,
which, as in the above-mentioned larvae, says M. Cuvier, ‘ sont
deux longs sacs cylindriques, que s’étendent jusqu’ a l’extrémité
posterieure de l’abdomen, et se replient méme alors en avant.”
But, in the proteus, neither do the supposed lungs reach to the
pelvis, nor does the supposed glottis open into the air-bladders,
_ but issue in a cavity which communicates with the air-bladders
by two long conduits. Thus, then, the structure of the bran-
chial arches, the distribution of the bloodvessels, and the form
and size of the lungs in the proteus, differ entirely from the
corresponding organs in the siren and larvee of the salamander.
If, farther, we consider the mode in which frogs and sala-
_manders respire air, and compare it with that of the proteus,
‘we shall obtain still farther evidence of the differences sub-
sisting between them. All zoologists, including M. Cuvier,
now admit that frogs first receive air into the mouth through
the nostrils only, and from thence force it into the lungs by an
action resembling deglutition. But neither the proteus nor the
siren are able to respire in this manner ; for the nostrils in the
former do not open into the mouth, but beneath the upper lip ;
and in the siren, “ les narines, simplement creusées sur les
cétés du museau, ne pénetrent point dans la bouche,” says M.
Cuvier. Neither do these animals respire air in the manner of
serpents, for they are both destitute of ribs. When also the
_ proteus takes air into the mouth, it escapes rapidly through the
branchial apertures : nor is there any ground for believing that
any portion of it enters the very narrow chink of the glottis to
pass into its cavity, and from thence through the two mem-
branous canals into the air-bladders. No muscular structure
suited to produce such effects exists, and the fine membranous
canals, subject to compression every instant from the stomach,
altogether unfit them for performing the office of air-tubes or
bronchi. In all reptiles that respire air, the structure of the
organs is such as to permit free inspiration and expiration, how-
ever different the form may be; but in the proteus, the want
of ribs and diaphragm, the fact that the nostrils do not open
into the mouth, the extreme narrowness of the aperture termed.
glottis, and the narrowness, length, and compressibility of the

and. Structure of the Proteus Anguinus. 25

air-tubes, all shew, that in this animal none of those arrange-
ments exist, which nature has instituted with such great solici-
tude and skill in other reptiles, to carry on with ease and cer-
tainty the respiratory function, But it is needless to multiply
arguments, to prove that the air-bladders of these animals in no-
wise perform the office of lungs, since it has been already shewn
that, when taken out of the water, they die just as fishes do.

M. Cuvier justly observes, that those animals can alone be
deemed truly amphibious, “ qui respirent, 4 la fois, lair élas-
tique en nature, et celui qui contient leau:” and he then goes
on to state, that the strena lacertinu respires through its whole
life by lungs and by gills, and is therefore a permanently am-
phibious animal; but that the larvee of other reptiles make use
of these two different organs only for a short period, and are
therefore only temporarily amphibious. With all due respect,
however, to so great a zoologist, we, say the authors, are of.
opinion, that before pronouncing the siren to be permanently am-
phibious, it would have been proper to have made upon it, or
upon animals which resemble it, experiments similar to those we
have made on the proteus. If, in his researches with regard
to ambiguous reptiles, he had not contented himself with exa-
mining only their skeletons, but had examined also the larve
of the salamander, while yet alive, we are certain that his in-
vestigations would have conducted him to opinions entirely op-
posite to those which he has been led to form.

In our investigations on this pout, we have directed our
attention to the above mentioned Jarvee, to observe particularly
the changes which occur in their intimate structure, when they
are transformed into perfect animals *. Between the siren and
these laryze there is the greatest resemblance, not only in regard
to the structure of the branchial arches, but also to the nostrils ;
for, in the siren, as well as in these larvee, the nostrils do not

* The investigation here referred to, is contained in a memoir, entitled,
‘« Descrizione Anatomica degli organi della circolazione delle Larve delle Sala-
mandre Aquatiche, fatta dal Dott. Mauro Rusconi,” Pavia, 1817. The substance
of this memoir, we may, on a future occasion, communicate, from a belief that
few questions, either in a zoological or physiological view, possess greater interest,
or are at present less clearly understood, than the structure and transformation
of these supposed amphibious reptiles.—Transt,

26. Observations on the Natural History

open into the mouth. This circumstance prompted us to exa—
mine the condition of the bones of the face in these larvae, and
we have: thereby satisfied ourselves that the larva of the sala.
mander is unable to breathe-by lungs, until the maxillary bones,
the zygomatic arches, and the’ palatine bones are sufficiently
developed to form the canal of the nostrils, in such a manner
thatats pesterior extremity may open into the mouth. Before
this canal is so-formed, these larvae are unable to respire atmo-
spheric air, and, if taken out of the water, they then soon die ;
and, therefore, guided by analogy, we ineline to the belief, that,,
to the siren, whose nostrils ‘‘ ne pénétrent point dans: la: bouche,”
the same things ought to happen. Moreover,.as-its lungs: are:
similar in all respects: to those of the salamander, and are fur-.
nished with a true: glottis, we are farther of opinion, that-the
siren-is the larva of some reptile, the genus of which is as yet
unknown, and which will differ: from its larva in not possessing:
gills, and in having a trunk somewhat longer.

To return to the proteus.—We consider that it 1s not an am-
phibious: animai; having a double circulation, as some have-
maintained, but a perfect reptile, different entirely from all
others. It is a-reptile, in respect to its having a single circula-
tion, and a-fish,.in regard to its mode of respiration,—in other
words, it is a reptile which respires air mixed with water, . while
others respive atmospheric air: so that, were it allowable to re-
vive the old idea of-a chain of beings, the proteus might be
regarded as the link which would connect reptiles with fishes.

From the facts and: cireumstances above stated, it appears,
that the proteus: isan animal, which, like fishes, is capable of
respiring only im water. Its branchial circulation, however,
‘is only a fraction of the greater circulation, whence it follows,
that, in respiration, it consumes less oxygen than fishes do ;
and, consequently, a smaller quantity of blood in a given time
is changed in the gills of the proteus, than, in like circumstances,
is changed in the gills of fishes. From this circumstance, as.
appears to us, continue the authors, arise the imertness,. the
slow growth, the capacity of enduring fasting, the indisposition
“in the blood to coagulate, and, lastly, the power of living in a
stagnant water, where a fish of equal size would die. With re-
gard to the faculty of generating heat, the authors are unable

and Structure of the Proteus Anguinus. 27

to speak with confidence: on this and some other points they
were unable to satisfy their curiosity, having sacrificed all the
protei which they possessed to other researches.

The reader perhaps may expect, that after having thus set
aside the common opinion, that the two ’air-bladders of the pro-
teus perform the furction.of lungs, we should declare the pur-
-pose they are designed to serve. This, however, say the au-
thors, it is difficult to do, as it is to say what is the true and
‘primary use which the .air-bladder serves in ‘fishes ; but this
point, at a future period, they-hope to be able to investigate,
both in the protei and inishes.

Such is a condensed account of the labours of Professors
Configliachi and Rusconi, regarding the history and structure of
‘this singular animal. Those who may desire more minute in-
formation, must consult the work itself, and more particularly —
the numerous .and beautiful figures, designed by Dr Ruscomi,
_and engraved ‘by Anderloni, with which the work is adorned.

D. E.

a el

Explanation of Plates.

‘Plate VL Fig. 1. View of the head from below, eight times
greater than natural. aa, the two branches of the lower jaw ;

_ 66, processes of the temporal bones to which they unite; c,
the roof of the palate ; d, the os hyoides ; eee, the three bran-
-chial arches of the right side; fg, the .mtermediate bones of
‘the first and second arches; Ahh, the three ‘first vertebre ;
mn, the branches of the os hyoides.

Plate VI. Fig. 2. The skeleton of the proteus of its natural
size ; a, the three cartilages, sites, the shoulder ; 6, the
pelvis.

Plate VI. Fig. 3. The lower half. of the-trunk-of a fennel} pro-
teus laid open. a, the alimentary -canal phoreued and
straitened from the action of ardent spirits :—at its termina-
tion, it is slit up to shew the common focus of the ureters
and oviducts, into which two bristles are inserted, the open-
ing from the urinary-bladder is indicated by a single

28 Observations on the Natural History

bristle; 8, the left ovariwm, containing minute ova, and
drawn to one side to display the kidney underneath ; ¢, a
portion of the oviduct straitened by the action of the spirits;
d, the left kidney; e, the ureter running along its margin,
and terminating with the oviduct in the rectum ; f, a por-
tion of ‘the left air-bladder, in this instance remarkably en-
larged ; the corr apenas one of the right ‘side was very
small.

Plate VI. Fig. 4. The cranium laid open, to'shew the cerebral
mass and certain nerves springing from it ; aa, the two hemi-
spheres of the cerebrum; b, the cerebellum ; c, the medulla
oblongata ; d, the right olfactory nerve ; ¢, the origin of the
fifth pair of nerves ; J; the vestibule of the organ of hearing
laid open, in which the little sac is seen, and ‘the origin of
the acoustic nerves ; g, the facial nerve; h, the entrance of
the carotid into the cranium, from which springs the opthal-
mic going to the eye (n) ; m, the origin of the par vagum.

Plate VI. Fig. 5. Profile of the head and part of the trunk ;
a, the external aperture of the nostrils surrounded by pores ;
b, the doubling of the inferior lip, which is in part covered
by the superior; c, the swelling or protuberance produced

by the heart.

’ Plate VII. Fig. 1. A male proteus laid open, to exhibit the re-

»lative size and position of the viscera; a, the heart, with

its pericardium, opened and titrned back ; 660, the liver

drawn aside, to shew the viscera beneath it ; c, the stomach ;

d, the alimentary canal; ¢, the spleen; 2/, the pancreas ;

& the testicle of the left side; h, a part of the left kidney ;

2, the urinary-bladder ; k, the left air-bladder, with its tube,

opening into the conical cavity above; J, the anus or cloaca ;
m, the sinus’of the vena cava.

Plate VII. Fig. 2°: a, the heart reversed and turned upward ;
}, the short conieal canal cut longitudinally, which commu-
nicates anteriorly with the glottis, and posteriorly with’ the
cavity from which the two tubes, (cc) terminating in the
air-bladder, proceed.

Piate VII. Fig. 3. Head of the proteus viewed from below, eight
times greater than natural, displaying the circulating and res-
piratory systems ; a, the heart ; }, the arterious trunk spring-

wnd Structure of the Proteus Anguinus. 99

ing from it; ¢, its bulb; dd, the two primary trunks arising
from the bulb, and again subdividing; e, the first branch
of the primary trunk, or artery corresponding to the com-
mon carotid, and which subdivides into two, one branch (f/)
being continued to the first or exterior gill, and the other
(g) proceeding to the muscles of the os hyoides; h, the
vein which carries back the florid blood from the gill.

The second branch of the primary trunk (d) soon also
subdivides, sending off the branch (2) to the third gill,
and another (Z) to the middle gill. To these two
branchial arteries, the two vems (mm) which carry
back florid blood, correspond. 'The principal trunk of
this second branch, after receiving this florid blood,
sends off the artery (m), which, descending along the
air-tube, supplies the air-bladder and generative organs
in each sex ; it then curves upward, and from its cur-
vature gives off the vertebral artery (0), which, after
sending some twigs to the occiput, enters the vertebral
canal, and descends along it: it also gives off another
branch (p) to the temporal bone, and then making
another curvature downwards, it becomes a branch (q)
of the aorta, which, by uniting with its fellow of the
opposite side, it contributes to form. ‘The aorta (7)
gives off the brayichial arteries (ss), the mammary (z)
and the vessel ¢ going to the stomach ; the letter x de-
notes a portion of the vena cava cut off.

Plate VII. Fig. 4. A leaflet of the gill highly magnified, ex-
hibiting the branchial. artery (a), conveying dark blood to
the gill, and the branchial vein (0), returning florid blood

to the aorta.