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Poa: ACC TOONS

OF THE

—

AMERICAN PHILOSOPHICAL SOCIETY,

HELD AT PHILADELPHIA,

FOR PROMOTING USEFUL KNOWLEDGE.

VOL. XVII.—NEW SERIES.

UE LS Dy BY THE SOCPETY.

\ /
Luar’ A

Philadelphia:
MACCALLA & COMPANY, PRINTERS,
1893.

ee Nee aN ea Oo Be ViOm SV EL.

dy ae dS oR) Ae
ARTICLE I.
Description of a Skull of Megalonyx leidyi, n. sp. By Josua Lindahl, Ph.D. (With 5 plates)
. ARTICLE II.
On the Homologies of the Posterior Cranial Arches in the Reptilia. By E. D. Cope. (With 5 plates) .
ARTICLE III.
A Synopsis of the Species of the Teid Genus Cnemidophorus. By E. D. Cope. (With 8 plates)

Be PASsEe sy seas.
ARTICLE IV.

The Tribute Roll of Montezuma. Edited by Dr. Daniel G. Brinton, Henry Phillips, Jr., and Dr. J. Cheston
Morris. (With 6 plates) . ; 4 j F ‘ :

Part I.—The Written Language of the Ancient Mexicans. By Daniel G. Brinton, M.D., LL.D.
Part Il.—The Tribute Roll. By Henry Phillips, Jr.
Part I1[.—Physical and Ethnographical Characteristics. By Dr. J. Cheston Morris.

A= J dey Sh SESE Ace
ARTICLE VY.

The Saprolegniaceze of the United States, with Notes on Other Species. By James Ellis Humphrey, Sc.D.
(With 7 plates) . : j ‘ : : 5 ; :

ARTICLE VI.

Researches upon the Chemical Properties of Gases. By Francis C. Phillips, Ph.D. (With 3 cuts and
2plates) . : ; ; ‘ lhe ‘ , ‘ 5 i

149

ARTICLE I.

DESCRIPTION OF A SKULL Of MEGALONYX LEIDYI, nsp:

BY JOSUA LINDAHL, Pu.D.,

SPRINGFIELD, ILL.

Read before the American Philosophical Society, January 2, 1891.

The specimen to be described on the following pages belongs to Bethany Col-
lege, Lindsborg, Kansas. It was placed in my hands for description, three years
ago, by Prof. J. A. Udden, at that time holding the chair of Natural History in
Bethany College, and I wish herewith to express my obligation to the President of
the said institution, the Rey. C. A. Svensson, for having allowed me to retain it so
long, no less than to Prof. Udden, who first offered me this opportunity, and who,

at my request, has communicated a geological sketch of the locality where it was
discovered.

This is his letter:

Dr. J. Linpaut, Springfield, I. :

Dear Sir :—The fossil skull of Megalonyx, which I sent you three years ago, was found by a man in excavating a
sand pit near the southwest corner of Harper township, in McPherson county, Kansas.

The watershed between the Kansas and the Arkansas systems runs through McPherson county from east to west.
Near the centre of the county it crosses at right angles a shallow trough about ten miles wide, which contains a series
of small, undrained basins, and is known by well diggers in the county as the ‘‘old river bed.”’ This trough has for-
merly been one hundred and twenty five feet deeper than it now is, being filled to that extent by sediments burying
the red shales into which itis cut. Taken in ascending order, these sediments consist of (1) gravel and sand, contain-
ing rolled boulders of clay and angular fragments of cretaceous shales of various sizes up to a weight of a ton and
more (from near the bottom of this gravel the skull was taken) ; (2) a stratum of clay, observed only in two places, and
not known to be continuous over any considerable area; (3) a stratum of volcanic dust several feet in thickness, seen
at six different localities, extending twelve miles in a line across the trough ; (4) a fine dull orange-colored loam, up-
wards of seventy-five feet in thickness, and occasionally resembling loess.

Awe. Si VOll. -Xeville At

2 DESCRIPTION OF A SKULL OF

From the gravel and the sand have been taken the following fossils, determined by Profs. E. D. Cope and R.

Ellsworth-Call :
Equus major DeKay.

Spherium striatum Lam.

Spherium suleatum Lam.

Pisidium abditum Haldeman.

Anodonta, sp.

Valvata tricarinata Say.

Gammarus, sp. 5

Beds like these are found at various places on the Western plains, but they have suffered greatly by erosion.
Their occurrence in McPherson county is at a point marking the crossing of a line of minimum erosion (the water-
shed) over another line of maximum development (the trough).

A study of the region and the deposits, in my opinion, shows that (1) previous to the deposition of the Pleisto-
cene, the country was traversed by drainage channels considerably deeper than at present; (2) the time of the making
of the gravel and the sand was probably coincident with a period of increasing humidity ; (3) the gravel and the
volcanic dust were deposited in waters that did not cover the cretaceous ledges in the vicinity ; (4) floating ice was
present as an effective transporting agent, when the sand and gravel were being laid down.

In the gravel, a small boulder was found containing fossils, which have been identified by Mr. E. O. Ulrich as
belonging to the Lower Carboniferous. Large boulders are common, consisting of a pure white aggregate of micro-
scopic crystals of carbonate of lime. . Specimens of this material have been examined by Mr. George P. Merrill,
who says he has seen similar material from the Cretaceous of Texas. Both of these occurrences point to a southern
extension of the water in which the deposits were made.

Yours, most sincerely, J. A. UDDEN.

AUGUSTANA COLLEGE, Rock IsLAND, Inu., Dec. 10, 1890.

The specimen has not the appearance of haying been exposed to violence or to
the vicissitudes of long transportation previous to its discovery, its present defects
evidently being caused by careless handling afterwards. Prof. Udden had, therefore,
good reasons for his hopes that the balance of the skeleton might be found in the same
gravel pit. These hopes proved futile, notwithstanding his energetic labors, but he
was rewarded by recovering the only missing portion of the right zygoma, and also a
dorsal vertebra which may or may not have belonged to the same individual.

The original discoverers of the skull, ignorant of its value, removed both the
canine molars, to keep them as curiosities, and, for the same purpose, broke off the
protruding ends of five of the other molars, leaving only the 2d in the left maxilla
and the 2d and 4th in the right. In this operation they also removed portions of the
alveolar walls of the Ist and 5th molars and of the palatine and pterygoid bones
(Pl. IIT). The left canine molar was afterwards returned, though short of its pulp
end ; also, the inner half of the piece removed from the 3d right molar. The descend-
ing ramus of the left zygoma as well as the intermaxillary bones were not found.

Prof. Joseph Leidy (in his Memoir of the Extinct Sloth Tribe of North Amer-
ica, Smithsonian Contributions to Knowledge, Dec., 1853) described two skulls of
Megalonyx jefersont Harlan. One of them, originally belonging to Dr. D. D. Owen’s

MEGALONYX LEIDYI, N. SP. 3

collection, is now the property of the Indiana State University at Bloomington, Ind.
I will here refer to that specimen as the Owen specimen. The other, discovered by
Dr. M. W. Dickeson, belongs to the Philadelphia Academy of Sciences. I will call
-it the Dickeson specimen. These two skulls and the Kansas specimen now before me
are, as far as known, the only Megalonyx skulls hitherto preserved in any collection.
The Kansas specimen is specifically distinct from the other two, and has also in
other respects a particular value, in so far as it shows the structure of the entire zygo-
matic arch and of the turbinals, which bones were nearly destroyed in the specimens
described by Dr. Leidy. This paper will, therefore, supplement his as a memoir on
the genus Megalonyx. For easier comparison with Dr. Leidy’s figures, the figures
illustrating this paper have been drawn, with few exceptions, to the same scale as his.
They were executed by my old friend, Mr. A. M. Westergren, for twenty-five years
the able artist in the Royal Swedish Academy of Science, in Stockholm, now with
Prof. Alexander Agassiz, of Harvard.

Judging from the more perfect obliteration of the sutural connections in the
‘Dickeson specimen, Dr. Leidy has demonstrated that it belonged to an older indi-
vidual than the Owen specimen. The same argument places the age of the Kansas
specimen between the other two. The sagittal and occipito-parietal sutures are less
open than in the Owen specimen, but more so than in the Dickeson specimen. The
temporo-parietal sutures are entirely obliterated, and so is the suture between the
basi-occipital and the basi-sphenoidal bones, both of which sutures are distinct in
the Owen specimen.

Lateral view.—The obvious difference in the sagittal contour in the three skulls
(compare Pl. I with Leidy’s Pl. I and Pl. 1V) may be explained as owing to differ-
ence in age, and would then confirm the conclusion derived from comparing the
sutural connections. The still more striking difference in the facial contour in the
two specimens of M. jefferson is most likely a secondary sexual character. May it
not be that the males of these animals, like those of the recent cystophorine seals, had
some special adaptation of their nose for vocal purposes? The Kansas specimen
agrees in this contour more closely with the Dickeson specimen than with the Owen
specimen ; the latter having the nasal vault raised higher than the cranial portion,
which is not the case in the other two. It may thus be inferred that these two are
females, the Owen specimen a male.

As stated above, but little remains of a zygomatic arch in the two specimens of
M. jeffersoni. A special interest attaches to this arch on account of its extreme
diversity of form in the different genera of Edentates. Reinhardt* inferred from the

* Prof. J. Reinhardt : “ Kempedovendyr-Slegten Calodon ;’’ Copenhagen, 1878, pp. 329, 326.

4 DESCRIPTION OF A SKULL OF

strongly developed sagittal crest and temporal fossa that the zygomatic arch in Mega-
lonyx may, not unlikely, prove to be completely closed. Our specimen shows that
he was correct in his conclusion. I will here give a detailed description of this
structure.

The zygomatic arch.—The zygomatic process of the squamosal bone projects
outward and forward, asin MZ jeffersont. Its upper border descends first in a concave
curve for about 8 cm. from the inion (thereby differing from M. jeffersonz, in which the
corresponding line is strongly convex, Leidy, l.c., P). 1); along the following 4 cm. it
deviates less from a horizontal direction; and, finally, in its last 4 em., it rises gently
upward to meet the border of the malar bone, about 15 cm. from its origo on the
border of the inion. ;

The glenoid fossa is curved outward and forward, measuring 5 em. in length and
2.5 cm. in greatest width. There is but a rudimentary postglenoidal process, but the
antero-exterior margin of the fossa is expanded into a horizontally flattened exglen-
oidal process. The inferior border of the bone extends 4 em. in advance of this pro-
cess, and there meets the postero-inferior process of the malar bone. The space
between these two processes is more or less roughened.

The external surface of the zygomatic process, viewed from above, is sigmoid ;
but between its upper and lower margins it is more or less concave throughout. Its
least vertical diameter is 82 mm.

The anterior end of the zygomatic process slants upward and forward with a
gentle curve and finally makes a sudden turn upward and backward. ‘The corre-
sponding emargination in the malar bone does not describe a similar curve, but
passes, in its upper portion, with a beveled edge, behind (inside of) the edge of the
zygomatic process. The sutures are entirely obliterated in the arch of the right side,
but the left arch has been fractured accidentally, and the suture cracked open.
However, even on the right side (PJ. I) the location of this suture may be seen as a
line, from both sides of which the faces of the two bones slope in different directions.

There is a rough semicircular ridge on the inside of the zygomatic process, pass-
ing from its infero-anterior point to a point perpendicularly above the same. In front
of this ridge is a broad shallow fossa extending over a considerable portion of the
malar bone.

Leidy’s description of the malar process of the maxilla in M. jeffersoni (1.c., p. 9)
applies also to M. letdyz, except in the latter having the infra-orbital canals double,
a horizontal septum dividing each into two canals, one immediately above the other.
This individual presents, also, an asymmetry in these canals, for, whilst that of the
right side has but a rudimentary septum forming a complete partition only fora short

MEGALONYX LEIDYI, N. SP. 5

distance, a little behind the middle of the canal, the septum in the canal of the left
side is complete through its entire length, and is 6 mm. thick in the centre of its
anterior border. The anterior orifices are vertically oval, that of the right side meas-
uring 13.5 x 9 mm.; the upper orifice on the left side measuring 8 x 5 mm., and the
lower, 11 x 9 mm.

Resting on the zygomatic process of the maxilla, the root of the malar bone pro-
jects outward, backward, and downward, its antero-posterior. diameter being 12 mm.,
the intero-exterior 21.5 mm. in its narrowest place, about 12 mm. below the summit —
of the curve of the said process. About 9 mm. further down, on the interior side, is a
tuberosity forming the superior termination of an area for muscular attachment.
This area, 10 mm. wide and 41 mm. long, twists itself around the border of the bone,
so that its lower end faces directly forward. It is divided by a low, median longi-
tudinal ridge into two facets.

From the border, bearing this area, the external surface of the bone turns out-
ward and backward, and at the same time expands both upward and downward ;
the anterior border of the upper expansion forms the exterior border of the orbit, and
terminates about 5 cm. above the inferior orbital border in a postorbital protuberance;
whilst the downward expansion is prolonged into a free descending ramus, terminat- _
ing abruptly, 96 mm. below the inferior border of the orbit. A low ridge passes
from the infero-posterior corner of this ramus, on its exterior face, diagonally upward
and forward, dividing that face into two concave facets, of which the antero-inferior
is triangular in form, the other somewhat rhomboidal. The inferior as well as the
posterior borders of the ramus are attenuated to sharp edges; its anterior face is
triangular, and by a sharp ridge set off from the exterior face; its interior face is
smooth and convex.

Posterior to a line, which may be drawn from the postorbital protuberance of the
malar bone to the posterior margin of the descending ramus, the exterior face of the
bone bends more strongly backward, and the corresponding line on the interior face
is the anterior margin of the broad shallow fossa which extends to the semicircular
ridge near the distal end of the zygomatic process of the squamosal. The free pos-
tero-inferior margin of this laminar body forms a sharp edge, and, on the external
face, bordering on this edge, is seen a semicordate muscular impression, pointed
behind, oval in front, and reaching nearly half way towards the inferior margin of
the orbit.

A line drawn from the postorbital protuberance of the malar to the nearest point
of the zygomatic process of the squamosal, may be regarded as the base of the ascend-
ing ramus of the latter. Below this line the external face of the bone slopes down-

6 DESCRIPTION OF A SKULL OF

ward and forward; above the same line the ascending process slopes upward and
inward. It also points strongly backward. Its free borders are nearly straight,
except near the apex, where they suddenly converge, and near their bases, where the
anterior border gently curves convexly upon the postorbital protuberance, whilst the
posterior border makes a concave curve towards the superior margin of the zygomatic
process. The internal face of the ramus is strongly convex.

The entire span of the zygomatic arch is 25 cm., from inion to the farthest point
on the anteorbital margin, and 11.8 cm. from the inner curve of the zygomatic process
of the squamosal to the inner curve of the corresponding process of the maxilla. The
distance between the apices of the two rami of the malar is 18.4 em.

Superior view.—One of the most obvious differences in the three skulls is. pre-
sented by the divergence of the temporal ridges. A comparison of Plate II with
Leidy’s Plate II will tell this at a glance. The angle between these ridges is acute
in the Owen specimen, but broadly obtuse in the other. But the Dickeson specimen
has the same angle still more obtuse, and no specific value can therefore be attached
to these differences.

Posterior view (Pl. [V, Fig. 2).—Here the differences are more important. In
M. jeffersoni (L.c., Pl. VI, Fig. 3) the outline of the inion is semicircular; in ML lerdyz
it is decidedly polygonal, though with rounded corners. The upper portion of the
inion is in M. jeffersont flattened, and bordered below by a transverse crest. In M.
leodyi the corresponding portion bulges out to form a broad tuberosity, bordered
below by two transverse fossz, one on each side of the vertical crest.

foramen magnum is transversely oval, its horizontal and vertical diameters
respectively 48 mm. and 84mm. In M. jefersoni this foramen is circular, its diam-
eter 34 mm. (“16 lines,” Leidy).

Anterior view.—In comparmg Leidy’s Pl. VI, Fig. 2, with our Pl. IV, Fig. 1,
it should be remembered that the specimen figured by Leidy has the intermaxilla-
ries preserved, which ours has not. Other differences are such that it is hard to
tell what is of really specific importance or may be due to age or sex.

The nasal cavity.—The internal structure of the nose is much better preserved
in our specimen than in either of the skulls described by Leidy. A brief description
will therefore be in place here.

Behind the incisive foramen the anterior end of the hard palate is turned upward
and slightly inclined backward between the alveolar walls of the canine molars, to a
height of about 25 mm. Its upper edge is centrally produced in a triangular process
with acuminate apex. A nasal crest of the maxillaries commencing about 65 mm.
behind its anterior border, and resting on the median line of the floor of the cavity,

MEGALONYX LEIDYI, N. SP. 7

abuts on the front wall just described and participates in forming the apex of its
triangular process.

The upper bony septum of the cavity is formed by a perpendicular lamina, 48
mm. high and 2 to 4 mm. thick in its anterior margin. This lamina, which extends
115 mm. backward, has its free edge grooved for the attachment of the cartilaginous
septum. The distance between the antero-inferior corner of this lamina and the apex
of the triangular process below is 26 mm. The anterior margins of the nasal bones
project about 25 mm. beyond the perpendicular lamina. Attached to the intero-
inferior margins of the nasals, and about 30 mm. behind their anterior margins, ap-
pear the anterior margins of the ethmo-turbinals as vertical lamine, until in the
postero-superior recesses of the cavity, they expand their convoluted portions.

_ The mazillo-turbinals are very large. ‘Their anterior extremities show them to
be borne on the lateral walls of the cavity, near the proximal extremity of the canine -
molars, and thence to extend both upward and downward. The upper portion bends
around the alveole and bulges out externally, following, with a small interspace, the
form of the wall of the cavity. The lower portion extends into the cavity between
the maxillary wall and the nasal crest. The inner side facing the narial septum is
flattened. The vertical height of the whole maxillo-turbinal is at least 8 cm., the
upper portion being the higher; the antero-posterior diameter is about 9 em. At
the anterior margin of its root on the maxillary wall is seen a circular foramen with
raised borders, appearing as the projecting end of a tube.

Capacious air sinuses extend backward in the root of the pterygoid (PI. IiI), and
branch off from there forward into the alveolar wall of the maxilla.

Inferior view, and sections of the skull—The distinctive characters of MZ. lecdyi
are best expressed in its proportions. Leaving out measurements and plates from
Leidy’s “Memoir,” his description would exactly fit to our specimen, as well. Per-
haps the most striking peculiarity of the latter is the far lesser prominence (depth)
of its maxillary portion. This will be most readily appreciated by comparing the
sections, Pl. V, Figs. 1-6, which were constructed with great care, Figs. 1, 3 and 5
from the Kansas specimen, and Figs. 2,4 and 6 from a plaster cast of the Owen
specimen.

Sections 1 and 2 were taken vertically and longitudinally through the sagittal
erest. The vertical distance between the base of the cranium and the most projecting
point of the hard palate in the specimens measured, is respectively 34mm. and 60 mm.

Sections 3 and 4 are transverse, nearly vertical, sections of the same specimens,
immediately in front of their 2d molars and anteorbital margins.

Sections 5 and 6 are also transverse and vertical, passing through the anterior

8 DESCRIPTION OF A SKULL OF

borders of the foramina rotunda |the locations of these foramina are indicated by
asterisks (**)], and thus at or near the narrowest portion of the cranium.

The pterygoid processes converge more rapidly forward in MW. jeffersoni (Lc,
Pl. II) than in M. lecdyz (Pl. 11), their most approximated points in the former
being just below the said foramina, but in the latter, at least 5 cm. more forward.
Their roots bend more outwardly, their horizontal interior portions are narrower, and
the anterior end of the basi-sphenoid, exposed to view between their inner margins,
is broader in the line of the section in M. jefferson¢ than in M. leidyz. The area be-
tween the root of the pterygoid process and the inferior border of the temporal fossa,
in M. jefferson, overhangs the said process, sloping upward and outward about 30°,
and extending as a plane in that direction about 3 em., when it suddenly bends ver-
tically upward, and finally makes a sudden turn inward and upward to its margin on
the sagittal crest. The same surface in MW. leidyi rises at once from foramen rotun-
dum more than 60°, and curves gently up to the crest without any sudden bend.
Sections 5 and 6 will show these differences plainly.

Dentition—The left canine molar, as much as is left of it, as well as the alveoles
of these molars, are but very slightly curved and are of uniform diameter. This
species thus belongs to Group “B,” in Cope’s Synoptic Table (E. D. Cope: Pre-
liminary Report on the Vertebrata discovered in the Port Kennedy Bone Cave, Am.
Phil. Soc., Vol. xii, 1871, p. 85). The group comprises but two other known species,
viz., M. wheatleyi Cope, and M. dissimilis Leidy. Cope makes the following dis-
tinction between the two:

“ Molars triangular ; canine molars less compressed—M. wheatley?.”

“ Last molar oval; canine molars more compressed—M. dissimilis.”

The third species of the group should be characterized thus :

Last molar ovato-triangular ; the others quadrangular; canine molars less com-
pressed—M. levdy.

It might be added that the exterior dentine layer, in both of the former species,
is thinnest at the bulge, whereas in JZ leidyi it has its maximum thickness at the
bulge.

The figures of the teeth (Pl. V, Figs. 7-9) are drawn with particular care. It
should be remembered that the triturating surfaces are preserved only of the Ist and
2d molars in the left maxilla, and of the 2d, 8d (partly), and 4th in the right maxilla,
and that the two 5th molars are broken off so high up as to expose their pulp cavities
(compare Pl. III). Even regardless of this, the teeth are not perfectly symmetrical.

In naming this species for the venerable paleontologist, Prof. Joseru Lerpy,
M.D., LL.D., of the University of Pennsylvania, I make but a small acknowledg-

MEGALONYX LEIDYI, N. SP. 9

ment of his admirable work on the osteology of the fossil Edentates—one of the
numerous fields in which his master mind has illuminated the way on which humbler
servants of Science endeavor to follow his lead.

Comparative Measurements of the Skulls of Megalonyx jeffersoni: and WM. leidyi.

MW. jeffersont. MW. leidyt.
Owen Spec. Dickeson Spec. Kansas Spec.
Length of skull from occipital condyles to anterior margin of Ist mm. mm. mm.
molar alveoli............ jocgousesscoosoaneagesaserssodce os 306 396 348
Length from inion to anterior margins of nasals.................. 311 2ooc 309
Length of temporal fossa to postorbital protuberance ............. 197 197 199
Depth of temporal fossa in a straight line.....................0.. 102 114 108
Length of face from postorbital protuberance ..................-. 119 112 115
Heishitiot face toymiddilelof hardipalatezeccya- ee tele ee ere slols 153 146 136
ie OC Dib PUNO GRUNT. ne coododacosnoacs0nsnde oO ae 127 101 °
Breadth << MG WG | BSiposokosocoscoondNedson sauer 95 95 83
a SG DM OSS OH Us wnOler Mh aco 4oscoscqnogecsscKE 114 114 101
iG SaecuiePOStOLbIta laprotulberanGesem cp eee) ace ae 127 138 123
IDIMTGICr Cl CHING OF WN WOECs so5qq0sccoanssesonGccogseddaudcuc 89 89 OY
Breadth of intermaxillaries, across their centres...........ssecees 85 * rite 453
Breadth of hard palate between ist molars ...................... 60 + oe 40
Length of interval between 1st and 2d molars.................... 50 + one 40
Length of face from ist to last molar alveolus ................... 178 ital 150
Length of maxilla from 2d to 5th molar alveoli, inclusive......... 95 + SB) 5 80§
Breadth of cranium at narrowest part of the temporal region ..... 89 102 91
Length of sagittal crest............. Be a rarerulsrmreieye pice neta eis eee 127 127 144+
Height of inion from inferior margin of foramen magnum.......- 110 110 107
Breadth of inion at mastoid processes..........-..------+------- 159 165 165

Capacity of brain cavity, 448 cu.cm. This indicates the weight of the brain to have been 16 oz.
(according to Owen’s rule: Comp. Anat. and Physiol. of Vertebrates, Vol. iii, p. 144; the
footnote).

1 According to Leidy (J.c. p. 18), unless otherwise stated. His measurements, in inches and lines, have here
been reduced to millimetres. X

2 This measurement is taken in a vertical plane passing close in front of the anteorbital borders.

3 Although the intermaxillary bones are missing, the areas of their attachment to the maxilla are well marked.

4 The anterior terminus of this crest is determined somewhat arbitrarily, the parietal bones leaving a wide
fissure between their margins, which gradually diverge and pass over into the ridges curving outward and forward to
the postorbital protuberances.

* Measured on Leidy’s plates.

+ Measured on a plaster cast.

§ Estimated.

Jo 125 SH—\VOI, BQYVIOI, 1835

10 DESCRIPTION OF A SKULL OF MEGALONYX LEIDYI, N. SP.

EXPLANATION OF THE PLATES.

Plate J.

Lateral view—two-thirds natural size.

late =i
Superior view—two-thirds natural size.
Fate Ae:
Inferior view—two-thirds natural size.
Plate IV.

Fig. 1. Anterior view—two-thirds natural size.
Fig. 2. Posterior view—two-thirds natural size.

Plate V.

Figs. 1, 3 and 5. Sections of skull of W. lecdyi

Figs. 2, 4and 6. Sections of skull of IL jeffersoni
Fig. 7. Dentition—natural size, and arranged on the plate in natural position.

(see page 7).

Figs. 8 and 9. Views of exterior side and triturating surface of left canine molar; natural size.

P. 8.—Prof. E. D. Cope, in letters to Prof. Udden, determined the teeth of Hguwus major, found in the same bed as
this skull, and also determined the age of the formation as belonging to the Hguus beds. He afterwards referred to
the skull, in Am. Nat., Vol. xxiii, p. 660, as ‘only found in the Ticholeptus formation of Kansas.’’ This was a lapsus
calamt which had escaped his notice until after the above was in type, and, at his request, it is hereby corrected.
His figures, Pl. xxxi, were reproductions of three photographs made in Kansas. The photographer had placed the
broken left canine-molar upside down in the right (the wrong) alveole.—J. L.

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24,6

ARTICLE If.

ON THE HOMOLOGIES OF THE POSTERIOR CRANIAL ARCHES
UN M800) leidled NIA

BY E. D. COPE.

Read before the American Philosophical Society, February 5, 1892.

At the meeting of the American Association for the Advancement of Science,
held in Troy, N. Y., in 1870, I presented the result of my studies of the arches which
distinguish the posterior part of the cranium in the Vertebrata, and especially in the
Reptilia. Three arches were considered, which were named, commencing with the
inferior in position: the quadratojugal, the zygomatic and the parietoquadrate. Of
these the only arch recognized as occurring in the Mammalia was the zygomatic.*
In the determination of this arch I followed Cuvier,+ and for the following reason.
It was supposed that the quadrate bone represented one of the ossicula auditus. As
this element in the Mammalia is intracranial, and does not give support to an arch,
the zygomatic arch of that class could not be homologous with the arch which it (the
quadrate) supports in the Reptilia (the quadratojugal). The zygomatic arch of the
latter class would be, on the contrary, that one which originates at the proximal
extremity of the quadrate, which would remain on the supposed withdrawal of the
latter within the skull as one of ossicula auditus.

Prof. Peters has, however, shown that the quadrate bone is probably not one
of the ossicula auditus, and he is followed by Dollo, Albrecht and others. In a study
of the osteology of the Permian reptile, Diopeus leptocephalus Cope,{ I came to the
conclusion that the quadratojugal arch of that reptile is the zygomatic arch of the

* Proceedings Amer. Assoc. Adv. Sci., XIX, 1870, p. 197.

+ Ossemens Fossiles, X, Ed. 1836, 14.

+ Clepsydrops leptocephalus Cope. Proceeds. Amer. Philos. Soc., 1884, pp. 30-42. Diopeus, gen. nov., described
on a later page. ;

12 POSTERIOR CRANIAL ARCHES

Mammalia, thus coinciding with the opinion as to the homologies of that arch held
by Hallmann, Owen and Peters, and as described by Gunther in Sphenodon. On
further study of the Permian reptiles contained in my collection, and comparison of
them with recent orders, I am more than ever convinced of the correctness of this
view, and I propose in the present paper to show the evidence on which it rests.
It follows, moreover, that if this interpretation be correct, the bone ordinarily called
quadratojugal must be called the squamosal or zygomatic, while the bone to which
that name is ordinarily applied must receive another name. The element immedi-
ately above the true squamosal, which roofs the temporal fossa in the Stegocephali
and Cotylosauria, is the supratemporal of Owen,* first described by him among
reptiles in Ichthyosaurus. The element immediately above the supratemporal in the
Stegocephali, Cotylosauria and Ichthyopterygia is the mastoid of Cuvier and Owen.
As it is probably not homologous with the part of the Mammalian skull called by that
name, some other one must be found for it. The numerous names given to bones in
this region of the skull all apply to the squamosal or supratemporal, so I propose to
name this one the supramastord.

Posterior to the supramastoid in the Stegocephalian and in some of the Cotylo-
saurian skulls, is an element which frequently projects in an angle in the posterior
outline, and which corresponds with the element present in the fishes, which Cuvier
termed the intercalare. The relation of this piece to the paroccipital of -certain rep-
tiles remains to be ascertained.

It is evident that the correct classification and phylogeny of the Reptilia will
not be completed without the determination of the homologies of these segments,
and the homologies of the arches to which they contribute. In the endeavor to
accomplish this analysis I have been much aided by a suggestion made by Dr.
George Baur, which has been fertile of valuable results. In a recent papert he says:
“Tn the oldest Batrachia, the Stegocephalia, we find a continuous dermal covering of
the upper and lateral parts of the skull; * * * the number of these dermal ossi-
fications is nearly constant. * * * The complete covering of the skull is for the
first time interrupted in the Ichthyosauria and Aétosauria{ by the appearance of a
supratemporal fossa, which develops between the parietal, squamosal and the upper
posterior border of the orbit. The bony arch below the supratemporal fossa, which
connects the orbit with the quadrate, is now affected in two different ways: I. The

*Suprasquamosal of Owen is the same; see Paleontology, pp. 168, 174, 198. Seeley uses the term supratym-
panic for the same.

y+ American Journal of Morphology, 1889, p. 471.

} Or Pseudosuchia.

IN THE REPTILIA. 13

broad single arch remains single, but becomes more and more slender and can be
interrupted. Plesiosauria, Theromora, Mammalia, Squamata (Lacertilia, Pythono-
morpha, Ophidia). II. In the broad single arch appears another opening, the infra-
temporal fossa, forming an upper and lower arch which connects the orbit with the
quadrate ; Rhynchocephalia; the whole Archosaurian branch (Crocodilia, Dinosau-
ria, Pterosauria); birds.” Dr. Baur then proceeds to identify the postorbital arch of
the Lacertilia with the quadratojugal or zygomatic arch, expressing the belief that
the ancestors of that order never possessed any other quadratojugal arch, and that
the present elevated position of the arch in the Lacertilia is due to reduction at the
inferior border. ‘Thus the supratemporal of the lizards (squamosal Auct.) would be
the equivalent of the quadratojugal of Sphenodon.

In the endeavor to reach a definite conclusion regarding these questions, I have
examined my specimens of the Reptilia of the Permian formation, as being most
likely to furnish essential facts. I now give the results of this examination.

I. Tue ReptriviA oF THE PERMIAN.

I have well-preserved crania which display sutures of the following species:
Chilonyx rapidens Cope; Pantylus cordatus Cope; Pariotichus megaloys Cope;
Edaphesaurus pogonias Cope; Clepsydrops natalis Cope; Naosaurus claviger Cope;
Diopeus leptocephalus Cope.

The genera Chilonyx, Pantylus and Pariotichus have the temporal fossz entirely
roofed over, thus belonging to the Cotylosauria,* to which must be probably referred
the genus Pariosaurus Owen, of the South African Karoo formation, and the Phane-
rosaurus of the German Permian. The other genera, excepting Diopeus, belong
to the Pelycosauria, which is probably the same as the Theriodonta of Owen.

CuILoNyYxf agrees with the Stegocephalia, and with other Diadectidz in pos-
sessing a distinct os intercalare. The component clements of the cranial roof are
equal in number and similar in position to those of the Stegocephalian skull, except
that the supramastoid extends between the parietal and intercalare to the posterior
border of the cranial table (Fig. 2, Sm.); and the supraoccipital does not extend onto
the superior face of the skull, except as a narrow border. The quadrate bone is
directed forwards instead of posteriorly, which causes an anteroposterior abbreviation
of the supratemporal and squamosal elements. The elements of the temporal roof

* Cope. American Naturalist, 1880, p. 304; October, 1889. Pariosauria Seeley. Philos. Transac., London, 1889,

p. 292.
+ Cope, Proceed. Amer. Philos. Soc., 1883, p. 631.

14 POSTERIOR CRANIAL ARCHES

are not exclusively tegumentary, but are identical in character with the bones of the
brain case, and the sutures are visible on the under as well as the upper side.

PANTYLUS* agrees with Chilonyx in the composition of its cranial roof with
the exception that the suspensorium is vertical and is not directed forwards. The
position of the supraoccipital and intercalare cannot be ascertained, owing to the
condition of the specimens (Fig. 4, Plate I).

PaRioticuus Cope} agrees in the main with Chilonyx, but the supraoccipital is
divided medially and is reflected onto the superior face of the skull as in Stegocephali.
The intercalare is reduced to a small element, of which a small part appears on the
superior face of the skull immediately behind the exterior part of the supramastoid
(Fig. 3, Plate I).

It is then these three genera which, according to Baur’s theory, represent the
type from which the reptiles with posterior cranial bars have been derived by the
development of foramina in the temporal roof. Let us see how this has been accom-
plished in the different types. I commence with the Permian genera.

The Theriodont genus, from the Permian of which I possess the best preserved
cranium, is Naosaurus Cope (Fig. 7). It is, unfortunately for our purpose, the
most extremely modified. The orbit is in the posterior part of the skull, and the
muzzle is greatly elevated and compressed. The zygomatic (quadratojugal) is
greatly decurved posteriorly, and the supratemporal is accordingly decurved also.
The postfrontal (Fig. 7a) is a narrow bone, wider than long, and it has connection
with the frontal, parietal and postorbital only. The postorbital is an L-shaped strue-
ture, of which the shorter limb is inferior, extending to the jugal, while the longer
limb is posterior, extending to the supratemporal, in contact with the parietal. It
encloses no foramen with the latter; but it encloses a larger foramen with the jugal,
zygomatic and supratemporal at the other boundaries. This is the infratemporal
foramen of Baur. Posterior to the parietal is a small transverse element, which appears
to be merely adherent to the former. Its determination is not easy at present. The
supratemporal is elongate vertically, and narrow anteroposteriorly. Beneath and
towards the middle line of the skull is a part of another bone, which may be the
paroccipital, or even exoccipital. The pineal foramen is distinct. No parietoquad-
rate arch.

In Cxiepsyprops{ the structure is apparently the same, although the form is
much less modified. ‘The quadrate articulation is nearly in line with the maxillary
dental series (Fig. 6, Plate II), and the jugal is nearly horizontal; its inferior border

*Cope, Bullet. U. 8. Geol. Survey Terrs., 1881 (8vo).

| Proceeds. Amer. Philos. Soc., 1878, p. 508.
+ Cope, loc. cit., 1878, p. 509.

IN THE REPTILIA. 15

being concave upwards. No bar extends posteriorly from the postorbital, which
joins the supratemporal, enclosing with it the infratemporal foramen. No indication
of the supratemporal foramen can be found in the rather mutilated specimen. I think
it was not present.

In EpApHosaurus Cope (Fig. 5, Plate IT), the skull is of a more depressed type
than in the preceding genera. The postorbital is mainly preserved, and it is in con-
tact with the frontal (postfrontal) proximally, and sends out no bar posteriorly. There
was apparently no supratemporal foramen, but a very large infratemporal, which
extended well upwards. There is no parietoquadrate arch. An element, perhaps
supraoccipital, terminates in a free appressed apex on each side of the median pos-
terior region. This may be homologous with the small free bone described in
Naosaurus, in nearly the same position. The stapes is very large, and is at least
partially perforated near the expanded proximal extremity. It is probably fully per-
forated, as I have described it in the Diopeus leptocephalus Cope.

In DiorEus Cope, the supratemporal is elongate in the vertical direction, and as
elsewhere, it overlaps the quadrate at the distal extremity. Anteriorly, it sends
forwards a process probably for union with the postorbital bone, which is, however,
entirely free from the parietal, and encloses a foramen with it, precisely as in
Sphenodon. It further resembles the corresponding element in Sphenodon in send- ©
ing upwards a branch for union with the parietal. Thus there are in this genus two
posterior bars and two foramina, thus differing widely from the other Permian genera
of this or any.other country known to me. Whether it has a free parietoquadrate
arch I do not know, but it is probable that the genus should be referred to the
Rhynchocephalia, in the neighborhood of Paleohatteria Cred. It differs from
Sphenodon and resembles closely the Theriodonta in the absence of an obturator
foramen, and in the character of its dentition.* The zygomatic bone is not excavated
below, but has a straight outline to its junction with the jugal. The quadrate con-
dyle is double like that of Sphenodon and the Clepsydropide (Fig. 8, Plate II).

The THERIODONTA described by Owen appear to have the single cranial arch
constructed in the same way as I described above as characteristic of the American
forms. I gather this from Owen’s figures of the genera Kistecephalus Ow., Galesau-
rus Ow., Scaloposaurus Ow., Anthodon Ow., and apparently Lycosaurus Owen.

The ANOMODONTA appear to have a differently constructed posterior cranial
region. In my study of the skull of Lystrosaurus Copet (Proceeds. Amer. Ass.

Ady. Sci., 1870, XIX, p. 205), I showed that this genus possesses an extensive supra-

* Proceeds. Amer. Philos. Soc., 1884, p. 33.
+ Ptychognathus Owen (preoccupied) ; Ptychosiagon Lydekker, 1889. -

16 POSTERIOR CRANIAL ARCHES

temporal foramen, and that the bone which bounds it externally consists posteriorly
of the supratemporal bone, and not the zygomatic. Anteriorly this bone joins the
postorbital, postfrontal and malar. Jn the Transactions of the Royal Society for
1889, p. 244, Prof. H. G. Seeley analyzes the structure of the skull of Dicyno-
don, which he shows to resemble closely that of Lystrosaurus, and his analysis of the
posterior arch and foramen is the same as my own in the latter genus. It is evident
then that the Anomodonta differ from the Theriodonta in the absence of a zygo-
matic arch, and in the presence of a supratemporal arch, which is separated from the
parietal bone by a supratemporal foramen (Figs. 1-2).

Fie. 1. Fre. 2.

Fig. 1. Lystrosaurus frontosus Cope. An Anomodont from South Africa ; skull from above, Fig. 2, do., from
right side. The lower Sq is the supratemporal.

The South African genus ProcoLopHon Ow. has been analyzed by Seeley* in
an admirable manner. The orbit is greatly enlarged, so that the region of the bars is
contracted. However, there is a zygomatic arch, an infratemporal foramen, and no
supratemporal foramen, thus agreeing with the Theriodonta, and not with the
Anomodonta.

In conclusion it appears that there are four types of crania represented in the
Permian Reptilia, which are distinguished as follows:

Demporal root Wminterrup ted! cicjejererstcreteteteleieerssielelelele sreieieteiteetieieiat atest eerie Cotylosauria.

A zygomatic arch, but no distinct supratemporal or supramastoid arches........... Theriodonta.
4ygomatic and supratemporal archesic\. sass sss seid ¢ bestanieiiee ee eee ee eee . Diopeus.
No zyeomaticha/supratemporall archieacetece cerieieiesaeieee een eaneaen ieee Anomodonta.

* Philos. Trans. Roy, Soc., 1889, p. 269.

IN THE REPTILIA. 17

Il. Tae Mesozoic REPTILIA.

We may now examine how far the cranial types above described continued into
Mesozoic time, and ascertain whether any new forms appeared.

In the first place, AzTosAuRuS Fraas presents a single foramen perforating an
otherwise continuous roof of the temporal fossa. This foramen is bounded below by
the postorbital and supratemporal bones. The postfrontal bone is closely joined to
the parietal, and has no posterior extension except to the postorbital. The zygomatic
arch is present and is continuous with the supratemporal and postorbital bones, there
being no infratemporal foramen. These details are derived from Faas’ figures copied
by Zittel in his Handbuch der Paleontologie.* In this figure no distinct zygomatic
(quadratojugal), or supramastoid, is visible, but whether they are wanting or fused
with adjacent elements, examination of specimens will best show. This genus is made
the type of a suborder of Crocodilia by Baur (Pseudosuchia), but it appears to me
to be typical of a special order (Pl. IV, Fig. 2).

The genus IcHTHYOSAURUS presents especial features. Here we have a zygo-
matic arch, and no infratemporal foramen. ‘There is a superior foramen, however,
which is bounded below by the postfrontal bone in front, and the supramastoid be-
hind; which are themselves in contact below with the postorbital and the supratem-
poral. This foramen I call the supramastoid. A paroccipital bone is present in this
genus,’but no intercalare. See my memoir of 1870 above referred to (Pl. V, Fig. 1).

The DinosauRiA may be represented by Diclonius, of which I have a complete
skull before me (PI. III). Here there are superior and inferior foramina which isolate
two arches, of which the inferior is the zygomatic. ‘The superior arch consists of the
supramastoid bone posteriorly, and apparently the postfrontal anteriorly. The supra-
temporal, small in Ichthyosaurus, has now disappeared. There is a distinct paroc-
cipital lying seale-like on the exoccipital. In Diclonius the supramastoid is fused
with the parietal, but in Iguanodon, according to Dollo, it is distinct.{ The fact
that the postfrontal and postorbital are not distinct from each other in the Dinosauria
with which I am acquainted, makes the determination of the character of the supe-
rior arch somewhat difficult. This is probably the case in Diclonius, and is so repre-
sented by Dollo in Iguanodon. Ina fine cranium of the Laramie Lelaps incras-

* Page 644, Fig. 569.
+Cope. Proceeds. Acad. Phila., 1883, p. 110, Pl. V. In this description and plate the sutural lines supposed to

separate the postfrontal from the postorbital and ‘‘squamosal”’ are of doubtful existence in the specimen.
+ Bulletin de Musée Royale d'Histoire Naturelle de Belgique, I, 1888, p. 235, Pl. II.
A. P. S.—VOL. XVII. C.

18 POSTERIOR CRANIAL ARCHES

satus Cope,* I find the bone in front of the arch to form two limbs of a nearly right-
angled triangle, one of which is supraorbital, and the other postorbital. No suture
divides it. It may represent the fused postfrontal and postorbital elements which we
have in some Lacertilia. There is, however, a small free bone horizontally placed at
the internal side at the posterior extremity of the supraorbital limb, which may be a
postfrontal bone. In this case the anterior connection of the supramastoid bone will
then be with the postorbital. This must however be clearly proven before it can be
accepted, since it is the postfrontal bone ¢ which articulates with the supramastoid
posteriorly. If we suppose the long perpendicular postorbital process of the bone in
question to represent the postorbital bone of Ichthysaurus, the question is simplified,
but it is not certain that such is the case.

The figures given by Marsh of the “Ceratosaurus” nasicornis represent a struc-
ture similar to that of Laelaps, and similarly indecisive. The figures of Hypsirhophus
stenops{ (Stegosaurus Marsh) exhibit distinct postfrontal and postorbital bones.
They show the postorbital produced upwards and backwards to form the horizontal
bar with a posterior element. Between this element and the parietal is represented
on one side of the figure another element, but this entire region is left undescribed in
the text. The appearance given by one side of the figure (3) is that the supramas-
toid and supratemporal are both present, and that the latter is the posterior element
in the bar. In that case the structure is that of the Theriodonta and Lacertilia, and
not that of the Ichthyosauria.

The situation in the CRocoDILIA appears to be the same as in the Dinosauria.
Nothing satisfactory can be learned from the recent members of the order; and even
in the skull of an Alligator mississipprensis one inch long, the postfrontal and post-
orbital bones are not distinct from each other: The Jurassic forms of the Teleosau-
ridz show the same character, and give the appearance of a postorbito-supratemporal
arch.§ In the Triassic Belodon the structure seems to be essentially similar. The
appearance in the PrrrosAurRIA, as figured by authors, is the same as in the
Dinosauria, but I cannot pronounce decisively in the lack of specimens. It is not
unlikely that all the members of the Archosaurian series resemble each other in this
respect, and I suspect that it is to be explained by reference to the Theriodonta.
Here the postfrontal and postorbital are distinct, as already pointed out, but the for-
mer is small and is crowded by the adjacent elements. Its fusion with the post-

* Which I owe to the Geological Survey of Canada.

+ Including the supposed squamosal of my description of Diclonius (J.c.).
+ Amer. Jour. Sci. Arts., 1887, Pl. VI.

$See Eudes Deslongchamps Notes Paleontologiques, 1863-9,

IN THE REPTILIA. 19

orbital would be probable. The arch is then supratemporal, and this element may
be fused with the supramastoid in the Dinosauria.

If the RayNcHocEPHALIA of the Mesozoic had the same structure as Spheno-
don, we may ascribe to them an infratemporal foramen and a zygomatic arch. The
former is bounded above by a bar which consists anteriorly of the postorbital, and
posteriorly, in all probability, of the supratemporal. Hence the postfrontal and
supramastoid do not communicate as they do in the Ichthyopterygia; and the large
foramen above the superior bar has different boundaries below from that observed in
Ichthyosaurus, but is like that of the Anomodonta. Hence I call this foramen the

FIG. 3,

Fic. 3.—Mosasaurus sp., suspensorium of 0s quadratum of right side, one-third nat. size; from Greensand of
New Jersey. A, from front; B, from behind; 0, fractured end of proximal half seen at fracture, a-b ; Hxo, exoccipi-
tal ; Pe, petrosal; Pao, paroccipital ; Sts, suture for supratemporal; QA, articular surface for quadrate ; #0, fenestra
ovale; VIZ, foramen for eighth nerve; a 3, line of fracture.

supratemporal foramen, and the bar the supratemporal bar. In Sphenodon the par-
occipital and supratemporal are fused together. The supramastoid is fused either
with the supratemporal or the parietal (Fig. 9, Pl. II, and Fig. 3, Pl. IV).

In the PytHonomorPHA and LacertiLiA the zygomatic arch of the Rhyncho-
cephalia has disappeared, leaving the superior or supratemporal arch only. That this
is truly the supratemporai arch and not the supramastoid is shown by the fact that
its anterior connection is with the postorbital as in Sphenodon, and not with the post-

20 POSTERIOR CRANIAL ARCHES

frontal. I cannot agree with Baur that this arch in the lizards is the zygomatic arch
of the other Reptilian orders. The supramastoid bone is, in the Lacertilia, wanting,
but whether by atrophy or by fusion with the parietal, forming the supramastoid pro-
cess of the latter, I do not know. An element intervenes between the supratemporal
bone and the parietal above and the exoccipital within, which Dr. Baur regards as
the supratemporal. With this I do not agree, and for the following considerations :
In neither adult nor young Lacertilia is there present any other element which
can be regarded as the homologue of the paroccipital of Ichthyosaurus, the Testu-
dinata and Dinosauria. In the Pythonomorpha this element is deeply embraced be-
tween the petrosal (prootic) and exoccipital, precisely as is the paroccipital (Fig. 3).
In the Lacertilia it is carried on the extremity of these elements. Moreover the
supramastoid is a purely roof-bone, and has no connection primitively with the
petrosal, and very little with the exoccipital. It cannot be identified with the supra-
temporal because it exists contemporaneously with that element in Ichthyosaurus,* as
well as in the Cotylosaurian genera Chilonyx and Pariotichus above described. I
therefore maintain the homology of this bone with the paroccipital as I presented it
in my paper of 1870, where I used for it Huxley’s term “opisthotic.” (PI. IV, Fig. 5).
Parker, in his paper on the Development of the Skull in the Lacertilia,; did not dis-
cover a distinct ossification in the position of paroccipital, although he finds a portion
of the exoccipital marked off by a shallow groove, which he calls opisthotic. The

true paroccipital he calls the “

second supratemporal.”

In the Opuipia there is no zygomatic or supratemporal arch, and the supratem-
poral as well as the supramastoid bones have disappeared. The paroccipital is the
only one of the suspensors of the quadrate remaining. ‘This element had been gen-
erally homologized with the “squamosal” (supratemporal) by authors, but in my
paper of 1870 I identified it with the paroccipital of the Lacertilia (“‘ opisthotie ;”
supratemporal of Baur), with which Baur agrees. In the more specialized snakes its
squamosal attachment to the cranial wall resembles that of the squamosal bones of
higher Vertebrata, and its general position is that of that element. When, however,
the lower snakes, e.g., Ilysia, are examined, it is found to have the same position in
the embrace of the exoccipital and petrosal bones, as in the Pythonomorpha, and to
be clearly homologous with that element which I have thought to be the paroccipital
GSE Bicc6):

In the TrsTUDINATA, as pointed out by Baur, no foramina have been devel-

*The process of the parietal which joins the supramastoid arch in Diclonius (Plate IIJ) may represent the supra-

temporal.
+ Philosophical Transactions Royal Soc., 1879, p. 631.

IN THE REPTILIA. 21

oped, but the primitive roof has suffered diminution by absorption from the inferior
edge, or from both the inferior and the posterior edges. In Chrysemys, where a bar
has been produced (PI. V, Fig. 5), it consists of the unseparated zygomatic and supra-
temporal, the anterior elements of which are the jugal and postorbital ; and the poste-
rior, the zygomatic and supratemporal. The supramastoid is wanting even in the
genera (Hydraspis e. g.) with a parietoquadrate arch. The postfrontal and post-
orbital are not distinguished. In genera, where the posterior excavation is very deep
(e. g., Trionyx), the connection between the postorbital and the supratemporal is
interrupted, and a zygomatic arch remains (Pl. V, Fig. 6). It was comparison
of this type with the Lacertilia that led Baur* to conclude that the bar of the
latter order is the zygomatic.

The SAUROPTERYGIA possess but a single arch, and this is the zygomatic accord-
ing to the description of Nothosaurus given by Yon Meyer. The supratemporal
has no anterior connections according to this author, and the supramastoid is not
described. From all that I can gather from Owen’s descriptions and figures of
Plesiosaurus the structure is the same; which is confirmed by observation on such
imperfect specimens as are accessible to me. ‘The postfrontal is not continued above
the large temporal foramen; nor is the postorbital continued posteriorly. In the
latter point the structure differs from that of the Theriodonta. The type of the
Sauropterygia may be derived from that of the Theriodonta by the extension of
the infratemporal foramen upwards to the parietal bone, thus cutting off the posterior
connections of the postorbital and postfrontal bones. In this respect this type
resembles the Testudinata (PI. V, Fig. 4).

The Mesozoic reptiles (including the existing orders) present us then with the
following types of postorbital structure :

I. One foramen; generally a zygomatic arch.

No supramastoid bone ; postfrontal and postorbital fused ; a paroccipital............ Testudinata.
iPostirontialandepostorpitalidistinChas= screenees ssc ines ee tce acc Wescc esac ss: Sauropterygia.

Tee AC supramastoid foramen only.
Supramastoid and zygomatic arches not distinguished from each other ; a paroccipital,
Ichthyopterygia.
III. A supratemporal and infratemporal foramina.
SU pLaMmaspoOmsand ayecomatie ALC MES. apa seers inaiet fee valesi vem <elecciey aitherasiaja Weenie cies eisai, Crocodilia.
Dinosauria.
Plerosauria.
Rhynchocephalia.

* Amer. Journal of Morphology, 1889, p. 473.

22 POSTERIOR CRANIAL ARCHES

Iy. A supratemporal foramen only.

Zygomatic and supratemporal arches present and not separated by an infratemporal foramen,

Pseudosuchia.
A supratemporal and no zygomatic arches ; a paroccipital.......................---- Lacertilia.
Pythonomorpha.

V. No arches or foramina.
Quadratesuspended ol joaroce poi taller yee eee eee leek tenet Ophidia.

These structures must be considered in determining the systematic position of
the groups above enumerated, but their characters are not all of equal systematic

value.

III. Tur PARIETOQUADRATE ARCH.

This arch is not present in the Batrachia, and is very variously developed in the
Reptilia. It is produced by the separation of the posterior elements of the tem-
poral roof of the Stegocephali and Cotylosauria, from the elements of the brain case
below them. ‘That is, by the development of a foramen between the supramastoid
and supratemporal above, and the exoccipital and paroccipital below.

The parietoquadrate arch is a later appearance in geologic time. It is not
present in any of the Permian orders. The earliest indication of it is seen in the
Ichthyopterygia, where a space appears between the very large supramastoid above,
and the exoccipital and paroccipital below. It is wanting in the three Archosaurian
orders, but is represented by a fissure in the Triassic Belodon, and in Crocodilia in
general.* In Testudinata it is potentially present in the posterior part of the tem-

poral roof, but is only distinguished in certain Pleurodira (Hydraspis), where the .

supramastoid element is lost, or fused with the parietal processes which form its
proximal part. In the Rhynchocephalia it is well developed in Sphenodon, but here
also the supramastoid element is not distinct, being fused with either the supratem-
poral or parietal. The arch has the same character in Lacertilia, except that the
paroccipital sends upwards a brace along its inferior border. That this element is
the paroccipital has been already shown by reference to the structure in the Ichthyo-
saurus and in the Pythonomorpha (Fig. 8).

The space enclosed below the parietoquadrate arch I propose to call the parieto-
quadrate foramen. Its presence is an indication of systematic value, but not in gen-
eral of a high grade. Thus among the Squamata it is absolutely wanting in Ophidia,
and is scarcely elevated above the exoccipital in some Pythonomorpha. In Lacer-
tilia the foramen is much reduced in Feylinia, and is wanting in Anniella and the
Amphisbeenia, while it is large in most other types.

*See Deslongchamps, E., Notes Paleontologiques, I, 1868-9, Caen et Paris.

IN THE REPTILIA. 23

IV. Sysrematic ConsIpERATIONS.

From the preceding facts certain results follow. The knowledge of the Permian
types enables us to trace the affinities of the orders of later ages with much more
precision than has been possible hitherto. In the first place, we derive the Testu-
dinata directly from the Cotylosauria, which realizes the theoretical type which Baur
correctly supposed to have given origin to all the later orders. Thus we need not
look for the ancestry of the Testudinata in any other group. This order then con-
stitutes Series I.

As Series IT we can take up the line in which the supramastoid foramen appears
_ ([chthyopterygia). This type is not clearly marked out in the Permian, but according
to Baur the Triassic Mixosaurus presents an approximately terrestrial form of Ich-
thyosauria, which can be probably traced to Permian ancestors. This series does
not seem to have been continued, but this is not to be assumed, as yet, without fur-
ther evidence.

As Series III we commence with the Permian Theriodonta, where an infratem-
poral foramen is first developed. In Diopeus a supratemporal foramen appears. The
latter represents the type of the Rhynchocephalia, and probably the Dinosauria, Croc-
odilia and Pterosauria. The loss of the supratemporal bar and preservation of the
zygomatic gives us the Sauropterygia. The loss of the zygomatic arch only, gives
us the Anomodonta; and the non-sutural articulation of the quadrate gives us the
Squamata. The loss of both the supratemporal and zygomatic bars gives us such
Lacertilia as Heloderma and Anniella, and the Ophidia.

The importance of the connections of the posterior bars of the skull is for the
first time appreciated in the present paper. It is difficult to learn these connections
from the writings of authors, so completely have they been neglected. For instance,
the terms postfrontal and postorbital are sometimes used indifferently by Marsh in
describing the crania of Dinosauria. It is true that in a few Lacertilia, as the
Varani, these elements are fused together. The supramastoid and supratemporal ele-
ments have been generally confused except in the Ichthyosauria, where both exist
together. It may be alleged that the difference between the supramastoid and supra-
temporal bars is not great, and that the one might have been readily transformed into
the other. But this supposition will not bear examination. When the one bar has
been established the other has been lost, and a recovery after such loss is not proba-
ble. This follows from the fact that the position of a bar is the result of the loss of
the Cotylosaurian roof from all other regions. The only case where the reduction
has not at first restricted the roof to the position of one bar or the other, is that of

24. POSTERIOR CRANIAL ARCHES

the Testudinata, where both sets of elements are included in a single bar. This com-
pound bar is, however, reduced to the zygomatic elements in the more specialized
forms, and is not unfrequently entirely lost.

Aided by these considerations we get the following phylogenetic series. Hach
one of them originated in the Permian epoch. This table resembles essentially the
one I gave in the article on the Evolution of the Vertebrata in the American Natu-
ralist for 1885, p. 247, in which all the later orders were traced to the Theromora,
the Lacertilian series through the Rhynchocephalia. The varied character of that
assemblage was not at that time suspected, but it is true that there is a great
resemblance between the orders now included in it, except in the matter of the
cranial roof and bars, and in the nature of the rib-articulations. The discovery that
Diopeus is allied to the Rhynchocephalia places that order in immediate relation with
the Theromorous series on the one hand; while a correct estimate of its cranial
structure places it in immediate relation with the Lacertilia on the other.

The five reptilian series might be then further defined as follows:

Quadrate fixed ; no supramastoid or supratemporal foramen or separate arch........ Theromora.
Quadrate fixed ; a supramastoid foramen and arch.............eeeeeeeeee ee eee Ichthyopterygia.
Quadrate fixed ; a supratemporal and zygomatic arch..................----++---e Archosauria.
Quadratetixed!; aizyeomatic arch only asec aee eee ieee ieee ee ee Synaptosauria.

Quadrate free ; no supramastoid foramen or arch ; a supratemporal but no zygomatic arch,
Streptostylica.

IN THE REPTILIA. 25

The Theromora are the earliest in time, and their order of Theriodonta presents
the nearest affinities to the Mammalia. The Cotylosauria, on the other hand, dis-
play the nearest relations to the Stegocephalous Batrachia.

Tn the following illustrations the phylogenetic successions are indicated by dia-
grams based on the skull of Pantylus cordatus. This is adopted as the most conye-
nient of the Cotylosaurian types to be taken as a standard, because it displays none
of the especial peculiarities that characterize Chilonyx, and is better known in the
lateral posterior region than Pariotichus. In the series which terminates in the
Streptostylica we commence with the Theriodont type in Fig. 1, with an infratem-
poral foramen only, and reach Diopeus or Sphenodon with both infratemporal and
supratemporal. This is naturally followed by Dicynodon with supratemporal
foramen and no zygomatic arch, from which we pass to the Lacertilia, which has the
free os quadratum. ‘The descent of the Lacertilia is from the Theriodonta through
the Rhynchocephalia, the Anomodontia being a lateral branch. The Archosaurian
line may commence with a form with a supramastoid foramen only, or one with an
inframastoid only. We know no type of the latter kind; and of the former we have
the aquatic Ichtbyopterygia. A terrestrial type of this order probably existed, which
represents the stock from which the Archosaurian line is derived. In this series the
order of development probably has been Crocodilia, Dinosauria, Pterosauria, as
represented in Figs. 9 and 10, Pl. V.

EXPLANATION OF PLATHS.
Plate J.

STEGOCEPHALI AND COTYLOSAURIA.
Fig. 1. Mastodonsaurus giganteus Jaeger, } nat. size ; from Fraas.

2. Chilonyx rapidens Cope, 2 nat. size; from above; premaxillary, maxillary, jugal and zygomatic regions
restored ; a, left side. Coll. E. D. Cope.

3. Pariotichus megalops Cope, $ nat. size; zygomatic region imperfect ; from above; a, left side. Coll.
E. D. Cope.

4, Pantylus cordatus Cope, $ nat. size ; occipital region imperfect ; from above; @, right side. The line pass-
ing through the postorbital, postfrontal and supratemporal is a fracture of the osseous roof. Coll.
E. D. Cope.

Plate IT.

THERIODONTA AND RHYNCHOCEPHALIA.
Fig. 5. Hdaphosaurus pogonias Cope, 3 nat. size ; with imperfect zygomatic region, seen obliquely from above ;
a, posterior view. Coll. E. D. Cope.
6. Clepsydrops natalis Cope, 3 nat. size; with superior posterior part of skull imperfect ; left side. Coll.
E. D. Cope.

Iso TEp SO OWING 1D)

26 POSTERIOR CRANIAL ARCHES IN THE REPTILIA.

Fig. %. Naosaurus claviger Cope, } nat. size; muzzle and lower jaw wanting, but restored from allied species ;
zygomatic arch partly wanting ; left side; a, from above. Coll. E. D. Cope.
8. Diopeus leptocephalus Cope, } nat. size ; supratemporal, zygomatic and quadrate bones; left side. Coll.
E. D. Cope.
9. Sphenodon punctatum Gray, skull 3 nat. size; right side. Coll. E. D. Cope, from Sir James Hector, New
Zealand.

Plate EL.

DICLONIUS MIRABILIS Leidy ; skull about one-fourth natural size, from side and above.

Plate IV.

DIAGRAMS OF SKULLS OF THE THEROMORO-STREPTOSTYLICATE SERIES; vertical and side views, based on Pantylus
cordatus.
Fig. 1. Theriodonta. Fig. 2. Pseudosuchia (from Zittel). Fig. 8. Rhynchocephalia. Fig. 4. Anomodontia.
Fig. 5. Lacertilia. #ig. 6. Ophidia.
The supramastoid-parietal suture is omitted in the Pseudosuchia to resemble Aétosaurus. The supratemporo-
supramastoid suture is omitted in the Rhynchocephalia in imitation of Sphenodon. All the teeth but
one are omitted from the Anomodonta, in imitation of Dicynodon.

Plate V.

THE ARCHOSAURIAN AND SYNAPTOSAURIAN SERIES; DIAGRAMS OF SKULLS, based on Pantylus cordatus.
Fig. 1. Ichthyosauria. Fig. 2. Crocodilia (Teleosaurus). Fig. 3. Dinosauria (Diclonius). Fig. 5. Sauropterygia
(Nothosaurus). /%g. 5. Testudinata (Chrysemys). Jig. 6. Testudinata (Trionyx).
In the Crocodilia and Dinosauria the supratemporal is omitted, and in Sauroptery gia itis fused with the supra-
mastoid. In Testudinata the supramastoid is omitted. In Dinosauria the postorbital and postfrontal
are represented as fused, although this may be an appearance only.

EXPLANATION OF LETTERING.

Pmza., premaxillary bone; Mz., maxillary ; J., jugal (malar); Z., zygomatic (quadratojugal) ; Z., lachrymal ;
NV., nasal; F., frontal; Pef., prefrontal; Pof., postfrontal; Pobd., postorbital; P., parietal; Sm.. supramastoid ; Sé.,
supratemporal ; Jnt., intercalare; So., supraoccipital; Bo., basioccipital ; Q., quadrate; Pg., pterygoid ; Stap., Stapes.

Transactions Amer. Philos. Soc. Vol. XVII. Par

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Transactions Amer. Philos. Soc. Vol. XVII. Part I. Plate II (Cope).

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Part I.

Plate III (Cope).

Transactions Amer. Philos. Soc. Vol. XVII. Part I. Plate IV (Cope).

Types of Reptilia,

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Types of Reptilia.

Transactions Amer. Philos. Soc. Vol. XVII. Part I. Plate V (Cope).

ARTICLE III.

A SYNOPSIS OF THE SPECIES OF THE TEID GENUS CNEMIDOPHORUS.
BY E. D. COPE.

Read before the American Philosophical Society, January¥1, 1892.

CNEMIDOPHORUS Wagler.

Natur. Syst. Amphib., 1830, p. 154 partim; Wiegmann, Herp. Mexic., 1834, 9; Dum, Bibr., Erp. Gen., V, 1839, 128 ;
Gray, Catal. Liz. Brit. Mus., 1 Ed., 1845, 20; Boulenger, 2 Ed., II, 1885, 360.

Sealy portion of tongue cordate behind, and non-retractile. Tail rounded. Teeth

longitudinally compressed. Head large, regular; ventrals large; frontoparietals and |
parietals distinct. A collar-fold and femoral pores.

This genus embraces many species of the Neotropical realm, exclusive of the
West Indian region, where it is replaced by Amiva.* Five species enter the Nearctic
realm, and all but one of these are restricted to the Sonoran region. The C. sealin-
eatus Linn. ranges the entire Nearctic excepting the Hudsonian and Alleghenian

districts, and the northern parts of the Central and Californian. The following are
the characters of the species:

I. Nostril between the nasal plates. Males with a spine on each side the preanal region.

A, 10-12 longitudinal rows of ventral plates.

Brachial shields small, no post-antebrachials ; 5 parietals; 4 supraoculars ; femoral pores 29-35 ;

Ol @, WBE NOVI 4 263545 aod cus poo ded 7 OODOS DO DUC CO GH EAOS OD COCOO SR aOneeS C. murinus.

AA. Ventral plates in 8 longitudinal rows.

Large brachials; no post-antebrachials ; 5 parietals ; 4 supraoculars ; femoral pores 19; olive
ADOVe wit maviehter dank-edmed (dorsal PANG s cc... cli. cele as oes -oeice ss cee cine. C. espeutit
Large brachials ; no post-antebrachials ; 5 parietals ; 4 supraorbitals ; femoral pores 18-24 ; olive

RA UDVO— OM at ON PIP DIEStTLP ES etaratatafelatya)-bapetcle!sts|eialer=\<fe)<telelela~ </aieis we ct sleisle C. lemniscatus.

Brachials very small ; black or blackish-brown with lines on the nape and spots on the outer side

Ot ANS MNOS og d seater sa soe GOnOGoO Coda pea Ad SCO COO IEE DOR aa coca CorC aOer C. nigricolor.

* Dr. Steindachner describes (Annalen des K. K. Natur. Hofmus., Wien, 1891, p. 374) three species as Cnemi-
dophorus centropyz, tumbesanus and peruanus, with large keeled dorsal scales, The last two have but one frontopa-

rietal plate as in Dicrodon and Verticaria, and all three have the other external characters of those genera. The
characters of the teeth are not mentioned.

A SYNOPSIS OF THE SPECIES OF

II. Nostril anterior to nasal suture.
1. Ventral plates in 10-12 longitudinal rows.

Dorsal scales granular ; edge of collar granular ; brachials large ; no post-antebrachials ; femoral
pores 10-12; 3 parietals ; 3-4 supraorbitals ; olive with rows of black spots, and 1 or 2 white
lines :on each SiGe scx <5j<19.6 disse’ «si cle erwin «eee mee eiomiaercis aioe See erecta rere C. lacertoides.

Dorsal scales coarse, flat; scales of collar very small; parietals 3; supraoculars 4; brachials
large ; olive with nine longitudinal lines above............---2.0+-+eeeeeeee C. longicaudus.

2. Ventral plates in 8 longitudinal rows.
A. Scales of collar not larger at edge, which is more or Jess granular ; supraorbitals 3 (pari-
etals 3 ; no post-antebrachials).

Ilind leg shorter, reaching meatus auditorius ; anal scales continuous with abdominals ; femoral
scales in 6-7 rows; brachials larger; anals 10-12 ; usually five stripes on each side,

C. deppet.

Nind leg longer, reaching nasal suture ; minute scales between abdominals and anals ; femoral
scales in 10-12 rows ; brachials smaller ; anals 10-12; only four stripes on each side,

C. guttatus.
AA. Scales of collar not larger at edge, which is more or less granular ; supraorbitals 4 (pari-
etals 3).
a, Prenasal not reaching second superior labial.
f. Post-antebrachial plates wanting.

Large; anal plates 10 or more ; brachials in 4-5 rows; femoral pores 24-5; hind leg extended
reaches ear’; stripes’ broad and irrepular..- 2) -- «=~ -eeeeeiee eeiee efstonieire ale C. maximus.

Medium ; anal plates 5-6 ; brachials in 4-8 rows ; femorals in 6-9; femoral pores 19-21; scales
generally coarse ; the hind leg extended reaches ear; stripes complete or broken up,

C. tessellatus.
Smaller ; anal plates 8-10; brachials 6 rows; femorals 8; femoral pores 25; hind leg extended

reaches prenasal plate ; yellow spotted on olive ground...................... C. variolosus.
Small ; brachial plates 5 rows; femorals 6 ; femoral pores 17 ; scales smooth; striped ; hind leg
TO CAL re. 2 Se he clases se Sbicoe coms ele eee te else ane Ree ee ee ener C. octolineatus.
Small; brachial rows 6 ; femorals 4-5; femoral pores 17; scales rough ; unicolor; hind leg to
CAT oo oseione a :o)s!aie. viele wie soiwieieie(soleustexeios eink ereisieial clele o's Aree ERR Ieee Ae eee nee C. inornatus.

AAA, Collar with large scales, the largest at the edge.
a. Anterior nasal] plate not reaching second superior labial.
f. Femoral pores 15 or more.
vy. No post-antebrachial plates.
Small; stripes persistent, no intermediate spots ; femur with a stripe behind ; femoral pores
15-17 ; head short, loreal plate higher than long ; femoral scales 7-8 rows; 5 infralabials,
C. sealineatus.
Large ; stripes more or less connected with spots which cut up the dark ground into spots and
crossbars posteriorly ; femur without stripe behind ; femoral pores 20-21 ; loreal plate longer
than high’; femoral’scales' 7=8: rows: o..ac. os ow cos ee neice ee eee C. grahamii.
Vis Post-antebrachial scales present. 3 i
Median gular scales smaller than those of collar; femoral pores 16-18 ; femoral scales in 8 rows ;
infralabials 6 ; 7 undulate black stripes on an olivaceous ground .......... C. septemvitiatus.
Median gular scales smaller than those of collar; femoral pores 18-23; muzzle elongate, loreal
onger than high; dark bands interrupted by larger or smaller light spots or intervals,

C. gularis.

THE GENUS CNEMIDOPHORUS. 29

ff. Femoral pores fewer than 15.

Femoral pores 12 ; 3 parietals ; 3 supraorbitals ; gray brown with 10 longitudinal stripes,
C. multilineatus.
Femoral pores 9-11 ; 5 parietals; 4 supraoculars; anals forming a triangle ; olive brown with
Gistripes Or) SOME! TOWS Of SpPOtSe. . 26. ccc. ccc e wees cree ee ce ee rec eeeoeses C. ocellifer.
aa, Anterior nasal plate reaching second labial.

Femoral pores 13; one marginal anal plate ; 6 white stripes ; STM eae aps ecvepcvere orotate ae C. labialis.

In this genus as in others, some characters which are constant in one species are
inconstant in another. The presence or absence of the sixth infralabial, and of the
frenoorbital plates, are of this nature. The number of femoral pores varies within a
small range in all of the forms. Anomalies in the division of the head plates are
rare, but sometimes occur in this genus. Such are the fusion of the symphyseal
and postsymphyseal plates, the presence of an additional labial plate, ete.

The discrimination of the North American species of this genus is the most
difficult problem in our herpetology. Nowhere are subspecies more clearly defined
than in Cnemidophorus, 2. e., definable geographical forms, which are not always true
to their characters.

The color markings differ in the same individual at different ages, and the age at
which the adult coloration is assumed differs in different localities. Some of the
species, €. g., Cnemidophorus sexlineatus, never abandon the coloration of the young of .
other species and subspecies. The same condition is characteristic of the C. deppei of
Mexico, the C. lemniscatus of Brazil, and other species. The process of color modi-
fication is, as I have pointed out,* as follows: The young are longitudinally striped

light spots appear between the stripes in the dark interspaces. In a later stage these

with from two to 7 stripes on each side of the middle line. With increasing age,
spots increase in transverse diameter, breaking up the dark bands into spots. In
some of the forms these dark spots extend themselves transversely and unite with
each other forming black cross-stripes of greater or less length. Thus we have be-
fore us the process by which a longitudinally striped coloration is transformed into a
transversely striped one.

The large number of specimens of the C. tesseilatus and C. gularzs in the
National Museum collection show that the breaking up of the striped coloration
appears first at the posterior part of the dorsal region (7. é., the sacral and lumbar).
The.confluence of the spots appears there first ; and finally (C. gularis semifasciatus),
where the color markings disappear, leaving a uniform hue, this also appears first at
the posterior part of the body. In the C. tessellatus rubidus the dark spots disappear
first on the anterior regions.

* Proceeds. Amer. Philos, Soc., 1885, p. 283.

30 A SYNOPSIS OF THE SPECIES OF

The species of Cnemidophorus inhabit dry open ground where they can observe
their insect prey, and watch their enemies. From the latter they escape by the ex-
treme rapidity of their movements, which renders it difficult to follow them with the
eye, to which they appear as a streak flying over the ground. For this reason they
are popularly known as “swifts.” They are nevertheless frequently caught and
eaten by snakes.

CNEMIDOPHORUS MURINUS Laur. .« ‘

Gray, Catal. B. M., p. 21; Dum. Bibr., Erp. Gen., V, 126 ; Bocourt, Miss. Sci. Mex. Rept., Pl. XX, Fig. 1;
Boulenger, Catal. Liz. B. M., III, 361, Leps murinus Laurenti.
Guiana, Curagoa, Trinidad.

CNEMIDOPHORUS ESPEUTI Boulenger.
Catal. Liz. B. M., III, 362, Pl. XIX.
Old Providence Id. ; Swan Id. ; both off the east coast of Central America.
CNEMIDOPHORUS LEMNISCATUS Daudin.

Gray, Catal. Liz. B. M., 21; Dum. Bibr., Erp. Gen., V, 128; Bocourt, Miss. Sci. Mex. Rept., Pl. XXe, Fig. 2; Bou-
lenger, Catal. Liz. B. M., III, 363.
Tropical South America east of the Andes.

CNEMIDOPHORUS NIGRICOLOR Peters.
Sitzber. Gess. Nat. Fr. Berlin, 1873, 76 ; Bocourt, Miss. Sci. Mex., Pl. XX¢, Fig. 3; Boulenger, Catal. Liz. B. M., 364.
Los Roques Ids. off La Guayra, New Granada. (Known only to me by descriptions.)
CNEMIDOPHORUS LACERTOIDES Dum. Bibr.
Erp. Gen., V, 134 ; Bocourt, Miss. Sci. Mex. Rept., X Xe, Fig. 10; Boulenger, Catal. B. M., IIL, 373.
Southern Brazil, Uruguay, Argentine.
CNEMIDOPHORUS LONGICAUDUS Bell.

Gray, Catal. Liz. Brit. Mus., 21; Bocourt, Miss. Sci. Mex. Rept., Pl. XX¢, Fig. 18; Boulenger, Catal. Liz. Brit.
Mus., III, 374.

Amiva longicauda Bell, Zool. Beagle Rept., 28, Pl. XV, Fig. 1.
Northern Patagonia.

CNEMIDOPHORUS DEPPEI Wiegmann.

Herpet. Mexicana, 1834, p. 28; Bocourt, Miss. Sci. Mex. Rept., p. 281, Pl. XX, Fig. 3; Boulenger, Catal. Liz. B. M.,
1885, 371.

There are three well-marked subspecies of the C. deppez, which differ in their
coloration, and in the number of their femoral pores, and which haye distinct geo-
graphical ranges. They are defined as follows:

Four with or without a median, or five narrow stripes on each side; sides green, unspotted ;
belly yellowish to black ; hind legs with large spots ; femoral pores 17-19...... C. d. deppet.

THE GENUS CNEMIDOPHORUS. 31

Five lateral and a vertebral stripe ; the lowest lateral a row of yellow spots on a green ground ;
belly black ; legs scarcely yellow spotted ; femoral pores 21-23......... C. d. decemlineatus.
Five lateral and a vertebral stripe; the lowest wide, and on the black sides, which have yellow
spots below the stripe, often defining vertical black bars ; belly yellowish ; legs little spotted ;
repenoney | joes IEG. sacdospoSonuan0sod0 ecs00GsseensoouddooScUDDsGoNaDE C. d. Vineatissimus.

Cnemidophorus depper depper Wicgm.

LI. c. Bocourt, 1. c. C. lattivitis Cope, Proceeds. Amer. Philos. Soc., 1877, p. 94.
One specimen from Guatemala, Van Patten, and two from Tehuantepec, Sumichrast.

Crenndophorus depper decemlineatus Hallowell.

Cnemidophorus decemlineatus Hallowell, Proceeds. Academy Phila., 1860, 482.
Three specimens from Central America and twelve from Nicaragua, C. Wright.

The largest form, and distinguished by its color and numerous femoral pores.

Cnemidophorus depper lineatissimus Cope.

Cnemidophorus lineatissimus Cope, Proceeds. Amer. Philos. Soc., 1877, 94.
Sixteen specimens from Colima, Mex., Xantus, and four from Guadalaxara, Major.

This form is the most distinct in color characters, which are perfectly constant,
and it is further characterized by the small number of femoral pores. It would rank
as a species if compared with C. d. decemlineatus only; varying from the type in the
opposite direction from that form.

CNEMIDOPHORUS GUTTATUS Wiegm.

Herp. Mexicana, 1834, 29 ; Bocourt, Miss. Sci. Mex. Rept., 285, Pl. XXc, Fig. 4; Boulenger, Catal. Liz. Brit. Mus.,
1885, II, 370.

This species presents several forms which may be regarded as subspecies until
their constancy can be proven. They differ as follows:

I. Brachial and postbrachial plates continuous ; few or no granules on the edge of
the collar.
Hourslichiistripes|Omen ChusiG ey MwLAarge)ainerel-tlereteteyeleteta stelle ol-1-soley= o/-}e7e]« 0) e/c1= o1-iels-1e C. g. immutabilis.

II. Brachial and postbrachial plates separated by smaller scales ; numerous granules
on edge of collar.

Four light stripes on each side ; small; back not spotted.................. C. g. microlepidopus.
Two light stripes on each side ; the back light spotted ; large.................... C. g. guttatus.
Winicolorsemal levels eis eats ter wia stevafeereataje stusleclelete ce tviviss Nvcle se sisiae ieee eevee C. g. unicolor.

Cnemidophorus guttatus immutabilis Cope.

Cnemidophorus immutabilis Cope, Proceeds. Amer. Philos. Soc., 1877, 93.

This form might be regarded as a species but for the fact that its characters are
not entirely trustworthy. Thus one of the specimens has a few granules at the mid-

32 A SYNOPSIS OF TILE SPECIES OF

dle of the edge of the collar, and there are a few smaller scales between the large

brachial and postbrachial scales.
Two specimens from Tehuantepec, Sumichrast, the larger equal in size to the

Amiva surinamensis.

Cnemidophorus guttatus microlepidopus Cope.
Cnemidophorus microlepidopus Cope, Proceeds. Amer. Philos. Soc., 1877, p. 370.
This form differs from the typical guttatus in color only, and may be the young.
The median dorsal region is, however, unspotted.
One specimen, Tehuantepec, Sumichrast.

Cnemidophorus guitatus unicolor Cope.
Cnemidophorus unicolor Cope, Proceeds. Amer. Philos. Soc., 1877, p. 93.
The form is represented by one of the smallest specimens. According to the
rule which prevails in this genus, it should be striped if merely the young of the C.
g. guttatus. The absence of stripes then indicates probably a race different from the

typical form of the species.
One specimen from Tehuantepec, Sumechrast.

Cnemidophorus guttatus guttatus Wiegm.

Cnemidophorus guttatus Wiegm., l. c.; Bocourt, l. c.; Boulenger, J. c.
Amiva gutiata Cope, Proceeds. Acad. Phila., 1862, p. 63.

Three specimens from Jalapa, Pease, in the Museum of the Philadelphia
A¢éademy.
The above specimens are of relatively large size, equaling the C. g. ¢mmutabilis.

CNEMIDOPHORUS MAXIMUS Cope.
Proceeds. Academy Phila., 1863, p. 104.

The largest species of the genus, equaling many of the Amivas in dimensions.
It inhabits the peninsula of Lower California.

This species varies in the number of its anal plates, some specimens having
fewer than others. The brachial plates also vary in number from six to eight rows.
Two young specimens (No. 12,658) in which the umbilical fissure is still open, are
about as large as the adult C. sealineatus. They have a median dorsal light stripe,
and two on each side on a blackish ground. Each of the two dark bands thus pro-
duced is marked by two rows of pale spots. In this they differ from the spotted

TIE GENUS CNEMIDOPHORUS. 33

striped form of the C- tessellatus and C. sexlineatus, which have but one series of
such spots. The femur and tibia are crossbarred, and the former is not marked with
a longitudinal stripe behind.

CNEMIDOPHORUS TESSELLATUS Say.

Baird, U. S. Pac. R. R. Surveys, Vol. X, 1859, Gunnison’s Report, p. 18.
Cope, Check List Batr. Rept. N. Amer., 1875, 46.
Amiva tessellata Say, in Longs. Exped. Rocky Mts., 1823, IL, p. 50.

Seales of the back and sides generally coarse, .05 mm. in diameter. Scales of
the collar not larger than those of the throat, the edge of the collar with smaller often
granular scales. Four supraorbital scales, the posterior smaller than the others.
These are separated from both the superciliaries and the frontal and frontoparietal by
granular scales whose extension anteriorly differs in different individuals. Fronto-
parietals as large as the parietals, truncate in front. Interparietal longer than broad,
longer than each parietal. The latter undivided. A transverse series of small plates
bound the parietals and interparietals posteriorly. Frenal plate longer than post-
nasal. One row of scuta in front of orbit, and below orbit, separating the latter from
the superior labials. Superior labials five to below middle of orbit, the fifth acumi-
nate posteriorly. Infralabials five.

Brachial scales in four to eight longitudinal rows (rarely five) counted at the
middle, continuous with antebrachials, which are in three rows (rarely two). Post-
antebrachials small, uniform. Femoral plates in seven to nine rows (counted at
middle and to the line of pores) and tibial plates in three longitudinal rows. Femoral
pores varying from nineteen to twenty-one in number.

Color varying from olivaceous black to olivaceous brown, which is marked by

light yellow or orange longitudinal stripes or spots on the dark ground, or reversed

by black spots on a light ground. The head is unspotted and unstriped, except
occasional maculations of the gular region. Belly from yellowish to black or spotted.
Limbs crossbarred or spotted, and not distinctly striped posteriorly.

The size varies from a length of head and body of 86 m. to 102 mm. In the
former the total length is 260 mm. ; in the latter, 350 mm. For more detailed mea-
surements see under the respective subspecies.

This species ranges over the Sonoran and Lower Californian regions and the
Pacific, nearly to the northern boundary of California. Its distribution is somewhat
coincident with that of the Hutenza elegans (omitting the Rocky mountains proper),
and its eastern border is overlapped by the range of the eastern C. sexlineatus. The

A. P. 8.—VOL. XVII. E.

a4! A SYNOPSIS OF THE SPECIES OF

range of variations of color seen in the C. tessellatus is about the same as that seen
in the C. gularis, although, with a few exceptions, the subspecies of the two may be
distinguished from each other by color characteristics, without examining the scale
characters. The parallelism is, however, very close, and shows the same line of modi-
fications. I refer more especially to these under the head of C. gularis.

The subspecies of the C. tessellatus are five, as follows :

I. Brachial scales 4-5 rows ; femorals 6-7 rows.

Blackish olive above with a median dorsal paler stripe, and three similar stripes on each side ;
bellysandithroatunspotied sence cee ece eres see ier eee ee ee eee C. t. perplexus.
Two pale stripes on each side only, the interspaces pale spotted, and frequently broken up into
black or olive spots so as to destroy their integrity ; generally sparsely black spotted below,

C. t. tessellatus.

No stripes, but 12-14 longitudinal series of pale spots on an olivaceous ground, more or less con-
fluent; hind legs with numerous pale spots; thorax, collar, and more or less of throat,
Le eee ae Serene AMEN ASA OGUC os aGsaGcun sco UOO0 C. t. melanostethus.

II. Brachial scales in 5-6 rows ; femorals 8-9 rows.

No stripes ; ground color dove brown, with 3 rows of more or less obsolete black spots on the
back, and vertical black bars on the sides ; abdominal plates pale, black edged ; hands and
inferior facesjor hind Wessiand tailored eylane etc cesses eet C. t. rubidus.

III. Brachial scales 7-8 rows ; femorals in 8-9 rows.

Four light stripes above, interrupted and connected with light spots and lines in the black inter-
spaces, sides, throat and inferior surfaces variegated black and white ; medium,

C. t. multiscutatus.

Cnemidophorus tessellatus perplexus Bd. Gird.

Cnemidophorus perplexus Bd. Gird., Proceeds. Acad. Phila , 1852, p. 128.
Cope, Check List Batr. Rept. N. Amer., 1875, p. 46.

The type specimen is the largest obtained, and is probably adult. Its colors are
rather obsolete, while those of three younger specimens are as strongly contrasted as
in the young of any other form. Among all the striped forms of the C. tessellatus,
this one is distinguished by the presence of seven stripes and no spots. It is, so far
as yet known, confined to the valley of the Rio Grande river.

Cnemidophorus tessellatus tessellatus Say.

Onemidophorus tessellatus Baird, 1. sup. cit. ; Cope, 1. sup. cit. ; Amiva tessellata Say, l. sup. cit.

Cnemidophorus gracilis Bd. Gird., Proceeds. Acad. Phila., 1852, 128 ; Baird, U. S. Mex. Bound. Surv., Report II, Pt.
II, Rept., p. 10, Pl. XXXIV, Figs. 7-14.

Cnemidophorus marmoratus B. & G., Proceeds. Acad. Phila., 1852, p. 128.

Cnemidophorus tigris Bd. Gird., Proceeds. Acad. Phila., V1, 1852 (April), 69; Baird, U. S. Mex. Bound. Surv. Repu.,
1859, II, Pt. II, Reptiles, p. 10, P]. XX XIII.

Cnemidophorus tessellatus tigris Cope, Check List Batr. Rept. N. Amer., 1875, p. 46.

Cnemidophorus undulatus Hallow., Proc. Acad. Phila., VII, 1854, June, p. 94

THE GENUS CNEMIDOPHORUS. 35

The adult differs from the young in color, and its colors may be best understood
by reference to the latter. In this stage the ground color of the back and sides is
black or blackish olive, and it is transversed by two light yellowish stripes on each
side. One of these starts at the occipital plate, and the other at the superciliary
angle. The lateral stripe which extends from above the auricular meatus in the C. t.
perplecxus is here wanting. There is sometimes a trace of a median dorsal stripe, but
generally not. Faint longitudinal lines are sometimes present between the stripes
mentioned. On the sides below the external stripe are three series of more or less
longitudinal spots, which outline three stripes; but they are not connected, excepting
sometimes in the transverse direction. This stage represents the C. gracilis B. & G.

In mature specimens rounded spots appear between the longitudinal stripes, and
the lateral spots become connected transversely so as to leave the dark ground color
in the form of irregular transverse bars (Nos. 3047, 4970 and 15,619). In some
specimens the median dorsal stripe is distinct, and is even divided into two (No.
11,978). Such specimens have six stripes very close together, but only the external
pair on each side are homologues of those of the C. sealineatus and C. gularis. In
the majority of adult specimens the light spots expand transversely and produce an
emargination on one side or the other of the black ground, or cut it into sections or
spots, by expanding in both directions. in the former case the dark stripes become
irregular or undulate in outline. This is the usual condition on the anterior part
of the body. On the posterior part of the body the dark ground is usually
broken into spots. In the type specimen of the C. tagris B. & G. the breaking up
of the black intervals had not been completed, although the specimen is of full size.
In typical specimens this part of the body is marked by three longitudinal rows of
transverse black spots. The upper surface of the tail is generally marked with brown
spots, sometimes rather large, but in other specimens confined to the keels of the
scales. In some they are wanting.

In the last modification the traces of stripes have almost or quite disappeared.
The upper pair are first to be interrupted by transverse and oblique extensions of the
irregularly shaped black spots, and the inferior stripes are finally interrupted and
lost in the same manner. Thus in Nos. 8633 and 3048, the spots are transversely
confluent in every direction, bearing only irregular areas of the white color, now be-
come the ground. These approach nearest to the C. variolosus m., and represent
the C. marmoratus of Baird and Girard. In the type of that supposed species a
trace of the inferior stripe remains on each side. The end of the fourth toe of the
extended posterior foot reaches the meatus auditorius, and there are twenty femoral

36 A SYNOPSIS OF THE SPECIES OF

pores on cach side. The length of the head and body is 85 mm.; in No. 8633 it is
100 mm.

Hallowell, in describing this subspecies as C. undulatus, recognized the differ-
ence between it and the C. ¢. perplexus, remarking that the present form has but two
light stripes on each side.

This form ranges the Sonoran and Lower Californian regions to Utah, inclusive,
and extends to the northern part of California.

Cnemidophorus tessellatus melanostethus Cope.

Check List Batr. Rept. N. Amer., 1875, p. 46.
Cnemidophorus melanostethus Cope, Proceeds. Acad. Phila., 1863, p. 104.

The coloration of this subspecies is something like that of the C. variolosus, but
that is another species. The interparietal plate is narrower than in the C. t. tessel-
latus, and the black breast and gular region are not seen in it.

A number of young specimens accompany the two adults described. They have
two narrow stripes on each side of the middle line, and the spaces between them con-
tain each a row of pale spots. The thorax is not black. These resemble the young
of C. t. tessellatus (C. gracilis), but the latter has brighter colors, and where the
spaces between the stripes contain marks there are delicate longitudinal lines (No.
3034, type of C. gracilis).

This form is only known from the Colorado river of Arizona.

A form very much like this subspecies has been named C. martyris by Stejne-
ger.* The two known specimens differ from the C. ¢. melanostethus in their smaller
size and in the extension of the black over the entire inferior surface. It is doubtful
whether it can be regarded as a subspecies. It is from the Island of San Martir,
Gulf of California.

Cnemidophorus tessellatus rubidus Cope.

This elegant form is represented in the National collection by seven individuals,
of which three are adult. To the usual characters of the species it adds some others.
Thus the scales are rather finer, being less than .56 mm. in diameter. The femoral
scales are more numerous. Femoral pores twenty-two. Small scales of collar bor-
der not granular.

There are three parietals, and the longest toe reaches the auricular meatus.
There are the usual three anals, with one in front of the median, which is, with the
latter, bounded by a few scales on the sides. Median gular scales rather coarse.

* Proceeds. U. 8S. Nat. Museum, XIV, 1890, p. 407.

THE GENUS CNEMIDOPHORUS. 37

Loreal longer than high. Small scales above anterior canthus of eye numerous and
rather prominent. The keels of the caudal scales are prominent, and except at the
base of the tail, in continuous lines.

The color of the upper surfaces in the adult is a dove brown. This is marked
on the back by three series of transverse black spots, which are well separated from
each other. In one specimen the spots are very narrow; in another they are nearly
obsolete on the anterior part of the back. On the sides similar black spots are more
or less confluent into vertical black stripes. The head and fore legs are uniform
brown above; the hind limbs have on a similar ground narrow blackish crossbars,
sometimes indistinct. Tail pale brown above with olive and brown spots. Inferior
surfaces straw colored tinged with green, and varied with black and red. The
abdominal scuta are black bordered, and the throat is black spotted, sometimes
strongly, sometimes faintly. The palms and sometimes the entire inferior surface of
the anus is a bright vermilion. Posterior and inferior sides of femora, inferior aspect
of tibia, and inferior side and distal half of tail bright vermilion.

The young specimens have traces of six longitudinal stripes of an olivaceous or
light brown color, and the spaces between them are crossbarred with black and
olive, as in the C. gularis marvarum, which this form closely resembles at this stage.
The black spots become more distinct with age, and the interspaces blend completely
with the stripes, so that the latter are ultimately completely lost in a common ground
color. The femora are reticulated with black on an orange ground above. The black
and red of the inferior surfaces are not so pronounced as in the adult.

Measurements. _M.
Roralglenet here Ge sais anes Ae ayaa eee demir does Swine acdsee eid <eeu since 340
env thatomposterionied > elOuealn smc iea tira cioarie mite sieie faces oie slelsiclejercinie es siaeiaiaiet= etal ees .024
LGD 1 COMER cb cos5sbc9scbosncaangoan ou sasnoosoUgOD Dab SOceNeSa0RN DasOc0nSaoRpOND 034
HENAN ID Wit, cooaseoubosoodacocespbcnoade Go ppDodadUONHODOEOLoToDoUHbaKSoRQdoumBoD 100
Lema OP Woe MIND. 6 cecossoopcoocaccooo coo cuNDONg0D Ue cENnUnODdcOnUnUODdODoCBaOOOOOEC 035
LGR OP ING! WT. 6 snescnoseadagbad0cq0c5b0 co0opCobODODOD b0bt NOOOODNBODDDOOSOHOGU0O 072
MELEE Lene OOb=rtae mateietelelelelstaleleicieleveletal=tolela(elaieleloiaieie\e(«la(cic« »\sivielele [sin lele/oleielela[e\siain/s/s[eleie\a,e 036

Cnemidophorus tessellatus rubidus Cope.

|
Catalogue Number. | Number Specimens. Locality. Whence obtained.
15,149 1 7)

50 1
1 1 5 ~ sate
5 { St. Margareta Id., Lower Cali- | U.S. Fish Commission Steamer

fornia. Albatross.

3 1
4 1
5 1 J |

38 A SYNOPSIS OF THE SPECIES OF

Cnemidophorus tessellatus multiscutatus Cope.

Onemidophorus tessellatus tégris B. & G., Cope, Proceeds. U. 8. Nat. Museum, 1889, p. 147; not of Baird and Girard.

Represented in the U. 8. National Museum by four specimens of medium size.
The muzzle is rather acute, and moderately elongate. The extended hind leg reaches
to the orbit. In two larger specimens there are six plates of the infralabial row, and
in two smaller but five. Four large anals, two on the middle line in front of the
marginal pair. These four are surrounded by a series of smaller plates as far as the

vent. Scales of the tail with the keels slightly oblique throughout. The peculiarity

of the subspecies is seen in the large number of rows of brachial scales (7-8 rows),
and femoral scales (8-9 rows). The former are not quite constant, however, one of
the smaller specimens having but six rows. Femoral pores 20-22. The scales are
smaller than is usual in C. tessellatus, measuring .33 and .25 mm. in diameter.

The color is generally of the C. tessellatus tessellatus type, but the black ground
color is more persistent. The light stripes are most broken up posteriorly, and the
communicating pale cross-spots are widest and most numerous. On the sides the
pale spots are of irregular shapes, being both longitudinal and transverse on a black
ground. Belly black and light olive in varying proportions. Gular region and collar
with transverse black spots or bands. Fore limbs black with light olive spots; hind
limbs brown with blackish reticulation. Tail brown above, black-spotted below.

Measuremenis. M.
Motalilenty ther ceteris cialaleeielesseeiisiaciel eee eerie wae obanodocodsns so Saas Noso0¢ 275
Length to meatus auditors ns «0 js\jciselteo-eleeincinceeeieeee iene ee ee eee eer 021
Bengt to collar. i cescyereieieis « «eve olelaseroaleleialelfeteieletelerslateleterstcie veils tele ie ieicetets ieteerte teeta .030
Wen'g thitosventt.\nrciciercisiciefoteielererverereieleisteieiers Dretcisineltteieeieieiciaeie Snacdb asoccatcasacas abshoasas .085
eno thiofstore lim Dreaicler-revelsrslelinic eieenice cet eerie Sralelefakeciercietelstets Syoretsieelcisteleietelaras .032
Tene thor Wind Vim be oyeye.cle)ojosoiel-lareleroleralolereieiere steyumralereteleretetetereintatetetslittaialetciel stalin teteteistet iene .065
Length of Wind £006: .<<:<,-/-crreieyeievesersercisetstsieictaisieteriereleisteteleieeieternieieis coboadcocqdanses steceo | ABH

Cnemidophorus tessellatus multiscutatus Cope.

Catalogue Number. Number Specimens. Locality. Whence derived..
a. ean
15,160 1 )
1 1 Cerros Island, west coast of | U.S. Fish Commission Steamer
2 1 Lower California. Albatross.
3 1

THE GENUS CNEMIDOPHORUS. 39

CNEMIDOPHORUS VARIOLOSUS Cope.

This species exhibits the general scale characters of the C. tessellatus, but pos-
sesses some peculiarities. The interparietal plate is twice as large as either parietal.
Infralabials five. The scales of the brachinm and of the femur are smaller and more
numerous than in the C. tessellatus. There are six rows of the former, four being
the usual number in the latter species ; and eight of the latter, six or seven being the
usual number. Brachial rows three; tibials three. Anal scuta with the lateral
scales rather larger than usual, giving four large and six small ones in all. Femoral
pores more numerous, twenty-five on each side. This species is especially character-
ized by the length of the hind leg, which reaches, when extended, to the postnasal
plate, instead of to the meatus auditorius only. The scales of the mesoptychium
extend all the way across, and are not interrupted at the middle by smaller ones as
in the C. ¢. perplezus. The marginal scales are smaller. Posterior gular scales are
smaller, bounded in front by the larger scales of the anterior gular region.

Total length 250 mm.; of head and body to vent 65 mm.; of head to angle of
mandible 10 mm.; to collar 24 mm.; to axilla 31 mm.; length of fore leg 27 mm. ;
of fore foot 12 mm.; of hind leg £5 mm. ; of hind foot 30 mm.

The typical specimen is of a size which would be fully striped if it belonged to
the C. maximus or C. tessellatus, being that of the eastern C. sealineatus. ‘There are,
however, no stripes, but the olivaceous ground of the superior surfaces is marked
with numerous rather small yellowish oval spots. Those of the sides are irregularly
disposed, but those of the superior surfaces are arranged in six more or less irregular
series. Of these the two external on each side correspond with the two external
stripes of the young of the C. tessellatus. On the nape the series lose their regu-
larity, and on the nape region they are more frequently transverse. The hind legs
are olivaceous, marked with numerous irregular oval yellow spots. No stripe on the
posterior face of the femur. Head without spots or stripes. Gular region dark
olive; thorax blackish ; belly yellowish, the scales with black bases. Tail olive with
scales above yellowish at the base, brownish beyond; below brown except the basal
fourth, which is yellowish with black spots on most of the scales. Posterior limbs
with oval yellowish spots on an olivaceous ground. Femur not striped behind.

This species resembles the ©. maximus in the increased number of its femoral
pores and femoral and brachial scales, but is distinguished by its much longer hind
leg, spotted coloration and much smaller size.

40 A SYNOPSIS OF THE SPECIES OF

Cnemidophorus variolosus Cope.

Catalogue Number. | Number Specimens. Locality. | Where obtained. | Nature of Specimen.

3066 1 Parras Coahuila,

Lieut. Couch, U.S.A. | Alcoholic.

CNEMIDOPHORUS OCTOLINEATUS Baird.

Proceeds. Academy Phiia., 1858, p. 255.
U. 8. Mexic. Boundary Survey, II, 1859, Pt. II, Reptiles, p. 10.
Cope, Check List Batr. Rept. N. Amer., 1875, p. 45.

This species differs from the young specimens of the C. tessellatus of equal size,
in the small number of its femoral pores, and in the absence of spots on the hind
limbs and sides, as well as in the additional pair of median longitudinal stripes. The
single known specimen is apparently adult, and is about equal in size to a half-grown
C. tessellatus, and smaller than the C. variolosus.

CNEMIDOPHORUS INORNATUS Baird.

Prozeeds. Acad. Phila., 1858 (Dec.), 255.
Rept. U. S. Mex. Bound. Survey, II, 1859, Pt. II, Rept., p. 10.
Cope, Check List Batr. Rept. N. Amer., 1875, p. 45.

This species is distinguished by a combination of characters. The rough scales
are peculiar to it, and it is the only species known to me in which the rows of brachial
plates exceed the femoral in number. It is the smallest species, and yet shows no
indication of stripes.

CNEMIDOPHORUS SEPTEMVITTATUS Cope.

Scales of collar large, in three transverse rows, the largest row on the edge;
scales of mesoptychium small, flat, those of gular region longer. Head narrower than
in any other species, the first and second supraorbital plates longer than wide, the
fourth well developed. Interparietal plate twice as long as wide, considerably nar-
rower than the parietals; both bounded posteriorly by some small plates. Loreal
much longer than postnasal ; no frenoorbital. Infralabials six on each side, the first
pair in contact throughout. Dorsal scales coarse, round, projecting upwards at their
posterior border. Brachial scales in six rows, antebrachials in three. One row of very
large post-antebrachials, bounded by smaller ones. Femorals in eight rows, tibials in
three. Femoral pores 16-18. Anal plates only three, separated from vent by a wide
granular space, and surrounded anteriorly and laterally by one row of small flat

THE GENUS CNEMIDOPHORUS. 41

scales. Legs rather short, hind foot reaching to half way between humerus and
auricular meatus.

Size above medium for the genus. Length of head and body to vent (tail in-
jured) 110 mm.; length of head to angle of mandible, 26 mm.; do. to collar 34 mm. ;
do. to axilla 42 mm. ; do. to fore leg 31 mm.; do. of fore foot 25 mm.; do. of poste-
rior leg 71 mm.; do. of hind foot 35 mm.

Color above light olivaceous brown, transversed by seven longitudinal broad
black stripes, three on each side and one on the middle line. On the lumbar region
the median band disappears, and the pale intervals are wider than the black ones ;
anteriorly the pale ground assumes its normal relation of stripes on a black ground.
The inferior commences at the orbit and passes over the tympanum; the next begins
above the anterior border of the orbit and marks the external borders of the supra-
orbital plates. The next issues from a parietal plate. Anteriorly the black inter-
spaces have a few small spots; posteriorly they become undulate through lateral
emarginations, and more posteriorly the first and second stripes are broken up into
quadrate spots, the third remaining unbroken. The hind legs are very indistinctly
marbled on an olive-gray ground. The fore legs are coarsely reticulated with black
on an olive ground. The lateral dark stripes extend to the orbit, and there is a
blackish shade on the side of the muzzle, just below the canthus rostralis. Lower
surfaces everywhere yellowish, unspotted, except a few black specks on the inferior
labials and sides of the gular region. ‘Tail olive above, yellowish below.

This species belongs to the C sexlinzatus series, as indicated by the scales of
its collar, but it has the coarse scales of the C. fessellatus. Its six infralabial
scales are found only in the former series. Its coloration resembles in some degree
the stage of the C. tessellatus tessellatus, called by Baird and Girard C. tigris, but it
has seven stripes instead of four, and the lateral stripes are broken up and not the
median, as is the case in the latter. It also differs from the latter in the marking of
the fore leg, and nearly uniform coloration of the hind leg; the reverse being the case
in the C. tessellatus. The striping of the head is also not seen in the latter. The
head is also narrower in proportion to its length.

This, perhaps the handsomest species of the genus, is represented in the collec-
tion by an adult female only. It represents the C. sexliéneatus in California.

Cnemidophorus septemviitutus Cope.

Catalogue Number. Number Specimens. Locality. Whence obtained. | Nature of Specimen.

2872 1 El Dorado Co., Cal.

Dr. C. C. Boyle. | Alcoholic.

AN5 Js (SS =—WOlis yale 19h

42 A SYNOPSIS OF THE SPECIES OF

CNEMIDOPHORUS SEXLINEATUS Linn.

Gray, Catal. Brit. Mus. Liz., 18, p. 21.

Dum. Bibron, Erp. Gen., V, p. 1381.

Cope, Check List Batr. Rept. N. Amer., 1875.

Bocourt, Miss. Sci. Mex. Rept., 273, Pl. XXe, 11.

Boulenger, Catal. B. M., II, 1855, 364.

Lacerta sexlineata Linn., S. N., I, p. 364.

Amivu sealineata Holbrook, N. Amer. Herp., 63, Pl. VI; 2d Ed., II, 109, Pl. XV.

Seales of collar large, in few rows, the largest at the border, larger than the
median gular scales. Scales of body minute, .033 mm. in diameter. Large gular
scales with abrupt posterior border extending entirely across throat. Four supra-
orbitals. Frontoparietals large as parietals, truncate in front. Interparietals nar-
rower than parietal, parallelogrammic. Labial scales five to below orbit; infralabials
five or six, the anterior pair in contact throughout. Brachial seales in six to eight
rows ; antibrachials in three; femorals in from six to eight. Femoral pores 15-17.
Anal plates three large ones; two posterior, one anterior. Longest toe of extended
hind leg reaching to meatus auditorius.

The young have six longitudinal light stripes on a dark ground, which persist in
adults; the dark interspaces being never marked by light spaces as in the C.
gularis. The limbs are pale spotted on a darker ground and there is a longitudinal
light stripe on the posterior face of the femur.

This is one of the smallest species, and it retains the young coloration every-
where. It is also distinguished by its short and high muzzle, and the absence of
postantebrachial scales. It covers the Austroriparian region of the Nearctic realm
and the eastern as far as the range of the Carolinian district, extending to Maryland
and Delaware, but not New Jersey. In the Central region it reaches north to the
Sand Hills of the Loup Fork river of Nebraska. Its southwest limit is in Texas.

Two specimens from Florida (one of them from Key West, No. 15,336) display

the anomaly of a fusion of the three large anal plates into one. All other Florida
specimens are normal.

CNEMIDOPHORUS GRAHAM Bd. Gird.

Proceeds. Acad. Phila., 1852, p. 128,

Baird, U. 8. Mexican Bound. Surv., II, 1859, p. 10, Pl. XXXII, Figs. 1-6.
Cope, Check List Batr. Rept. N. Amer., 1875, p. 45.

A distinct species which resembles in coloration the partly crossbanded forms of

THE GENUS CNEMIDOPHORUS. 43

the C. tessellatus-tessellatus. But two specimens are known, and one of these has five
and the other six infralabial plates. They are from Western Texas, between San
Antonio and El Paso.

CNEMIDOPHORUS GULARIS Bd. Gird.

Proceeds. Acad. Phila., 1852, p. 128.
Baird, U. S. Mex. Boundary Survey, Reptiles, Pl. XXXIV, Figs. 1-6.
Cnemidophorus guttatus Hallowell, Proceeds. Acad. Phila., 1854, p. 192.

This species is allied to the C. sexlineatus, but is distinguished by the presence
of postantebrachial plates, the more numerous femoral pores and the longer muzzle.
It is very variable as to size and color, but the dark spaces between the light stripes
are always marked, interrupted or completely broken up by light spots or spaces,
except in the young. The color variations are similar to those already mentioned
under the head of the C’ tessellatus but they are more numerous. Specimens from
Western Texas come nearest in character to the C. sexlineatus. It takes the place of
that species throughout Mexico, also replacing the C. ¢essellatus in the drier parts of
that country. Besides the characters already cited, this species differs from the C.
tessellatus in its finer scales. These measure from .25 to .33 mm. in diameter, while
those of the C. tessellatus measure .6 mm.; but this character does not always
hold good.

The subspecies of the Cremidophorus gularis differ as follows:

Stripes persistent, narrow, defined ; no black spots; femoral scales in 6-8 rows; hind legs yel-

- low spotted, and with a stripe behind ; smaller........... FR OD ODDO SO OCB ADOORE -C. g. gularis.

Stripes persistent, wide, ragged ; spots in interspaces irregular ; parietal plate very narrow ; muz-
zle elongate ; legs neither spotted nor striped ; large ; 8 rows femoral scales ; 6 infraiabials,

C. g. angusticeps.

Stripes vanishing, their interspaces with black crossbirs ultimately joining crosswise ; femoral

scales 8-10 ; hind legs spotted ; infralabials 5-6; large..... Dicfelsieleletsieleretore -. CG. g. mariarum.

Stripes broken up into rows of spots ; interspaces with yellow spots ; hind legs with or without

yellow spots ; no posterior femoral stripe; a frenodrbital ; 5-6 infralabials ; large,
C. g. communis.

Light stripes traceable anteriorly only ; black bands broken up into transverse spots by orange

spots on body ; hind limbs pale spotted ; femoral scales 7-8 rows ; infralabials generally 6;

TLC CII evavevere’ a oraieleie c's; cist cleletsio siove sieisielctoielclalsievers ciciaisioisls mite retetevelni= oie iainlolaisielorelaietale C. g. scalaris.

Anal plates 3-4; femorals in 8-9 rows ; femoral pores 21; 6 infralabials ; large scales of collar

equal ; stripes posterivrly obsolete ; interspaces in front spotted ; medium..... C. g. sericeus.

No light stripes ; olivaceous with three rows of black spots on each side on anterior fourth of
body ; femorals 8 ; infralabials 6; muzzle elongate ; limbs unspotted ; medium,

C. g. semifasciatus,

44 A SYNOPSIS OF THE SPECIES OF

No light stripes ; olivaceous with black bars on sides which cross back on lumbar region ; rump
and hind legs yellow spotted ; femoral scales 8 rowed ; infralabials 6; muzzle elongate ; me-
GH GanoadoaddDoogoseonCCcS eee leleieiotalelelatetefeleiatetcteta staretetatstetaelatatateiaetatsters eeeee O. 9. costatus.

The geographical distribution of the subspecies is as follows:

C. g. gularis, Sonoran region.

C. g. angusticeps, Yucatan.

€. g. maritarum, Tres Marias islands.

. g. communis, S. W. Mexico.

C. g. scalaris, Chihuahua and southward.
C. g. semifasciatus, Coahuila, Mexico.

C. g. costatus, Mexico ; locality unknown.

These forms may be compared with those of the C. tessellatus in color charac-
ters as follows. I have already remarked* that this series of variations follows quite
closely those pointed out by Huropean authors to exist in the Lacerta muralis.
These have been made the subjects of especial study by Prof. Eimer of Tubingen,
from whose paper} I extract the following points of comparison (see Plate XII).

Lacerta muralis.

L. m. campestris.

Cnem. tessellatus. Cnem. gularis. | Other Cnemidoph’i.

1. Longitudinally striped............ C. t. perplexus. C. octolineatus.
C. sealineatus.

2. Dark interspaces pale spotted......|C. ¢. tessellatus a. |C. g. gularis a. C. labialis.

3. Dark interspaces divided by light C. septemvittatus.
COWS socassosce cecccecccceeeee (CO. t. tessellatus B. \C.g. scalaris a. |C. grahamii. L. m. albiveniris.
4. Dark spots confluent transversely, ae bie
forming crossbars ..............+ C. t. tessellatus y. |C. g. scaluris Bp. wa rbteenae
5. Light spots not confluent; light C. g. costatus. L. m. tigris.
stripes broken up ; pattern reticu-
lated epmttencee o covcecccecssces |C. t. melanostethus. C. variolosus. L.m. punctulatofas-
6. Dark spots separate and ona brown ciata.
LOU eletecisteeslelsteieteeie eens C. t. rubidus. C. g. semifasciatus

There are some color forms in the Lacerta muralis which are not repeated in the
North American Cnemidophori, particularly those which result in a strong contrast
between the dorsal colors as a whole and the darker lateral colors, as a band. The
color variety, No. 6, of the Cnemidophori is not reported by Eimer as oceurring in
the Lacerta muralis.

* American Naturalist, Dec., 1891.
+Archiv. f. Naturgeschichte, 1881, 239.

THE GENUS CNEMIDOPHORUS. 45

Cnemidophorus gularis gularis B. & G.

Onemidophorus gularis Bd. Gird., Proceeds. Acad. Phila., 1852, p. 128.
Baird, U. S. Mex. Bound. Surv. Rept., Pl. XXXIV, Figs. 1-6.
Onemidophorus guttatus Hallowell, Proceeds. Acad. Phila., 1854, p. 192.

This form resembles the Sexlineatus more than any other, but always possesses
the postantebrachial plates, and more numerous femoral pores, which range from
eighteen to twenty-two. Occasional specimens are, however, intermediate between
the two. Its range is the Sonoran region.

Under this subspecies must be placed four of the series of forms which I de-
scribed in my paper on the Reptilia of Chihuahua as subspecies of the C. sealineatus,*
in the following language; two of the forms (Nos. 5, 6) being the C. g. scalaris M.:

“1. Six longitudinal narrow stripes with unspotted interspaces.........e.2+00-C. g. gularis (young).
2. Six stripes as above, the dark interspaces with small white spots...... 2000 U. g. gularis verus.
3. Six stripes as above, wider and very obscure ; small obscure spots .....C. g. gularis obsoletus.
4, Six stripes as above, but wider, and the spots enlarged so as to be confluent occasionally with
Hoe Disots SUMTOEE GoGo nooo nce ncdcacKDODD OC hodecaoagodo0boc afetelelelelelelare

_ “Of the above forms all are numerously represented in the collection. The modi-
fication of the color pattern described, is not entirely due to age, as some of the
largest specimens belong to Nos. 2 and 3. Nevertheless small specimens predomi-
nate in the No. 1, and No. 4 presents a good many small specimens.” The speci-
mens enumerated are as follows: +

Subspecies No. 1; Nos. 14,236-41-49-69 ; 14, 305.
Subspecies No. 2; 14,231-41,305-308.

Subspecies No. 3; 14,231-50-308.
Subspecies No. 4; 14,241-50-302-5.

These forms are not sexual, as several of them include both sexes.

Not having been fully persuaded of the distinction between the C. tessellatus and
C. sexlineatus series, I used the name C. s. tigris for a “sixth subspecies” of the above
table. The name was however misapplied, although the color pattern is identical
with that of the C. tessellatus tigris B. & G., with the exception that there are traces
of six stripes instead of only four. The smaller specimens referred to the C. s. sex-
lineatus differ from that subspecies in having well-developed postantebrachial scales.

The gradation in the color characters given is complete, so that no subdivision
into subspecies can be made. The case is exactly parallel with that of C. tessellatus

* Proceeds. Amer. Philos. Soc., (1885) 1886, p. 283.
+ The numbers are attached to lots, by the recorder, and not to individuals, and are hence sometimes duplicated.

46 A SYNOPSIS OF THE SPECIES OF

tessellatus, except that there are here no individuals with the stripes entirely oblit-
erated, and complete transverse stripes posteriorly. (Such specimens are the C. g.
scalaris ; see below.) The femoral pores are generally eighteen, but some have six-
teen, seventeen and twenty. In eleven of the specimens now before me, seven have
five infralabials, and four have six. These numbers do not coincide with the color

types.
Cnemidophorus gularis angusticeps Cope. ss
Boulenger, Catal. Liz. Brit. Mus., II, 1885, p. 366.
Cnemidophorus angusticeps Cope, Proceeds. Amer. Philos. Soc., 1877, p. 95.
This large form is easily recognizable by its peculiar coloration, and by the very

narrow parietal plate, which is about three times as long as wide. Four specimens
are in the U. 8. National Museum from Yucatan.

Cnemidophorus gularis martarum Gthr.
Cnemidophorus mariarum Giinth., Biologia Centr. Amer. Rept., p. 28, Pl, XX.

This also large form is distinguished from the other subspecies by the larger num-
ber of rows of its femoral plates, and by the coloration. In the young the dark spaces
between the light stripes are crossbarred with black instead of a light color as in the
other forms, and the result is crossbars on the sides in the adults, on the disappear-
ance of the stripes. The hind legs are covered with large round yellow spots. The
color pattern of this form corresponds with the Lacerta muralis maculostriata of
Eimer.

Two specimens are in the U. S. National Museum, one from the Tres Marias
islands, the typical locality, and the other of uncertain origin.

Cnemidophorus gularis communis Cope.
Cnemidophorus communis Cope, Proceeds. Amer. Philos. Sec., 1877, p. 95.

This subspecies reaches a larger size than any of the others of the C: gularis,
and its peculiar coloration of small (or sometimes large) yellow spots on a dark olive
ground, gives it a very distinct appearance. This form is identified with doubt with
the Cnemidophorus mexicanus of Peters by Bocourt. What Peters’ species is I have
been unable to ascertain.

About forty specimens were sent to the National Museum from Colima, Western
Mexico, by J. Xantus.

THE GENUS CNEMIDOPHORUS. 47

Cnemidophorus gularis scalaris Cope.

American Naturalist, 1891, p. 1135 ; (published March 1, 1892).
Cnemidophorus sezlineatus tigris ‘‘ B. & G.’’ Cope, Proceeds. Amer. Philos. Soc., 1886, p. 2883; not ©. tigris B. & G.

Muzzle moderately acuminate in adults ; frenal plate about as high as long ; fre-
nodcular plate generally wanting. Brachial scales small, in eight rows ; antebrachials
in three; postantebrachials in two or three rows. Femorals in eight rows. The
three large anal plates are bounded by several small plates laterally and in front. Fe-
moral pores nineteen; in one eighteen, and in one seventeen. Longest toe of
extended posterior leg reaching to front of auricular meatus. First and fifth toes
measuring opposite to each other.

Ground color pale, on the sides posteriorly light rosy orange. The dark color
only remains as narrow transverse black stripes which do not cross the middle line,
which is occupied by a longitudinal series of spots. This is due to the fact that in
the adults the black ground is completely broken up by the transverse extensions of
the light stripes, which are quite traceable in the young. In some specimens the
black spots do not fuse on the sides into transverse stripes (No. 14,302). All the
dark markings fade out on the limbs and sacral region, leaving a gray ground (in
alcohol) which is marked with rosy orange spots. ‘The lateral ventral plates and all
those of the thorax with the posterior or concealed face of the anterior leg, are black
or blackish in the adult. :

Measurements of adult (tail injured): Length to vent 93 mm.; do. to angle of
mandible 25 mm.; do. to collar 29 mm.; do. to axilla 26 mm. Length of anterior
limb 30 mm.; do. of fore foot 14 mm. Length of hind limb 67 mm.; do. of hind
foot 37 mm. .

Several specimens of this form are contained in the collection, and they agree
closely in all respects. In coloration it is perhaps the most ornamental of the genus.
It is well distinguished from the C. grahamii in color characters, as well as in the
presence of the well-developed postantebrachial scales. In the C. gularis it corre-
sponds exactly in color characters with the tigris form of the C. tessellatus tessellatus,
designated in the plate of colors (XII) as D and E.

Cnemidophorus gularis scalaris Cope.

Catalogue Number. | Number of Specimens. Locality. From whom oltained. Nature of Specimen.
8,319 5 Mexican Plateau 8S. of J. Potts. Alcoholic.
Chihuahua.
14,302 2 City of Chihuahua. |Edw. Wilkinson. Alcoholic.

48 A SYNOPSIS OF THE SPECIES OF

Cnemidophorus gularis sericeus Cope.

Scales of the collar moderate, subequal, in four or five rows, marginal scales
equal to the others. Mesoptychial scales considerably smaller than the gular scales,
which are large, and extend from one ramus to the other. Scales of the back
rounded, not prominent, small, measuring .033 mm. Supraorbital plates wider than
long except the anterior, and not separated from the frontoparietals by scales. Inter-
parietal large, not twice as long as wide; parietals subtriangular, as wide as the inter-
parietal, but much shorter. Frontoparietals remarkable for their small size, and from
their terminating each in an angle anteriorly, which receive between them the pos-
terior apex of the unusually narrowed frontal. They are smaller than the parietals,
which are smaller than in other species. If these characters prove constant, I shall
regard this form as a true species. Infralabial plates six on each side, the last one
small; the first pair separated at the posterior angle. Brachial scales in six rows ;
antebrachials in four. Femorals in eight, tibials in three rows. Femoral pores twen-
ty-one. The hind limb extended reaches the posterior border of the orbit.

Size medium. Length of head and body (tail injured) 81 mm.; length to angle
of mandible 22 mm.; to edge of: collar 26 mm.; to axilla 31 mm.; to fore limb
26 mm.; of fore foot 14 mm.; of hind leg 60 mm.; of hind foot 32 mm.

Ground color above anteriorly black, posteriorly olive. This is marked by
six narrow lines of a paler olive, which represent the lines of the C. sealineatus,
with an additional median dorsal one. These fade out or become very indistinct
on the lumbar and sacral regions. The interspaces black anteriorly, are marked
at first by small olive spots, but these enlarging, break up the black ground
into spots, but these fade out on the middle of the length. The superior sur-
faces of the limbs and tail are olive, the latter unspotted; the hind limbs
faintly spotted with paler above and posteriorly, and the forearm reticulated with
black posteriorly. The dorsal stripes, except the three median, extend as far as the
orbit. Rest of head olivaceous. Lower surface of head, limbs and tail, yellow, the
first named with a bluish transverse patch across the gular region.

This species has various peculiarities. It differs from the other members of the
C. gularis series in the larger number and more equal size of the seales of the gular
fold, approaching in this way the C. tessellatus, but not agreeing with it, since the
marginal scales are not smaller. It differs from all the species in the small size of the
interparictal and parietal plates. Its posterior legs are longer than in any species
except the C. variolosus. No species has four rows (or three at the narrowest part) of

THE GENUS CNEMIDOPHORUS. 49

antebrachial seales; the usual number being 3-2; and the femorals are more numer-
ous than in the Cg. gularis. The coloration is also quite distinctive. But one
specimen is known, and that is from Southwestern Texas. The discovery of other
specimens will determine whether this is or is not a true species. In the obsoles-
cence of the color pattern posteriorly it resembles the C. g. semifasciatus, following.

Cnemidophorus gularis sericeus Cope.

l |
Catalogue Number. Number of Specimens. Locality. | Whence obtained. | Character of Specimen.
|

15,650 | 1 San Diego, Tex. ‘Wm. Taylor. | Alcoholic.

Cnemidophorus gularis semifasciatus Cope.

Muzzle compressed, rather elongate ; frenal with frenoocular, longer than high.
Large scales of the collar confined to the middle portion, smaller scales appearing on
each side, and granules on the edge of the collar laterally. Posterior supraorbital
small and divided on both sides, perhaps abnormally. Interparietals as wide as pari-
etals, and extending farther posteriorly. Larger scales behind parietals few in num-
ber. Brachial scales in six, femorals in six rows. Postantebrachials in three or
four rows. Femoral pores twenty. Dorsal scales minute. Anal plates three large
ones with eight to ten smaller ones on the sides and in front. The hind leg a little
short, the longest toe, when extended, not reaching the meatus auditorius by the
diameter of the latter.

Total length 300 mm.; do. to angle of mandible 25 mm.; do. to collar 32 mm. ;
do. to axilla 42 mm.; do. to vent 100 mm. Length of fore limb 30 mm.; do. of fore
foot 13 mm.; do. of hind leg 64 mm.; of hind foot 36 mm.

The color is uniform olivaceous above and below, with the following black
marks: There are three rows of black spots on each side of the middle line above ;
the superior small, subquadrate, the second larger and transverse, the inferior forming
short crossbars. The superior row extends from the interscapular region to the mid-
dle of the length of the back; the second row extends farther and the inferior row
extends nearly to the groin. Limbs, head, belly and tail unspotted.

This form has various peculiarities which entitle it to be regarded as a subspe-
cies, and possibly as a species. But two specimens are known to me. In No. 38033
the black spots are smaller, and are restricted to the anterior fourth of the length of

do JE (Sh = OI, MBN IG (Ere

50 A SYNOPSIS OF THE SPECIES OF

the body, being most distinct in front of the scapular region. Here traces of the
original six stripes are visible between the spots.

It is possible that it may be demonstrated that the C. serzceus is established on
a female of this species with abnormally reduced frontoparietal plates. The colora-
tion is much like that of specimen No. 3033.

Cnemidophorus gularis semifasciatus Cope.

Catalogue Number. Number of Specimens. Locality. Whence derived. Nature of Specimen.
9248 | iL \Coahuila, Mex. Lieut. Couch. Alcoholic.

3033 | 1 Patos Coahuila. Lieut. Couch. Alcoholic.

Cnemidophorus gularis costatus Cope.

Cnemidophorus sexlineatus costatus Boulenger, Catal. Liz. Brit. Mus., II, 1885, p. 366.

Cnemidophorus costatus Cope, Proceeds. Amer. Philos. Soc., 1877, p. 95.

This form is totally distinct from all others in coloration. There are six infra-
labials and eighteen femoral pores in the only known specimen. ‘This is about the
size of a large C. s. gularis, or less than the C. s. angusticeps and communis. Exact
habitat unknown, but it is Mexican.

CNEMIDOPHORUS OCELLIFER Spix.

Peters, Monatsber. Akad. Wiss. Berlin, 1877, pp. 412-14.
Boulenger, Catal. Liz. Brit. Mus., Il Ed., 1885, p. 372.
Tejus ocellifer Spix, Spec. Nov. Lacert. Braz., p. 28, Pl. XXYV.
Cnemidophorus hygomti Rhat. et Liitk., Vidensk. Meddel., 1861, p. 231.
Bocourt, Miss. Sci. Mex. Rept., Pl. XX¢, Fig. 12.

Brazil.

CNEMIDOPHORUS MULTILINEATUS Philippi.

Archiv f. Naturgesch,, 1869, p. 41,
Boulenger, Catal. Liz. Brit. Mus., 2d Ed., II, 1885, p. 373.
From Mendoza, Argentina.

Unknown to me by autopsy.

THE GENUS CNEMIDOPHORUS. 51

CNEMIDOPHORUS LABIALIS Stejneger.
Proceeds. U. S. Nat. Museum, XII, p. 643.

This is the smallest species of the genus, and is well characterized by its scutal
peculiarities.
Cerros Id., coast of Lower California.

EXPLANATION OF PLATES.

Each plate includes the following figures: Superior, inferior and lateral aspects of head; superior view of arm
and inferior view of forearm ; inferior view of hind leg, with anal region; scales from side of body, with borders of
ventral plates. The figures are natural size except

Nore.—For the greater part of the material on which this paper is based, I am indebted to the U. S. National
Museum, and its distinguished directors, Profs. 8. P. Langley and G. Brown Goode.

Plate VI.

Fig. 1. Cnemidophorus tessellatus perplecus B. & G.; Specimen No. 3060 U. S. Nat. Museum.

Fig. 2. Cnemidophorus tessellatus tessellatus Say, a; Spec. No. 3041 U. S. Nat. Museum.

loie Vid:

Fig. 3. Cnemidophorus tessellatus tessellatus Say, 2; No. 4113 U. S. Nat. Museum.

Fig. 4. Cnemidophorus tessellatus tessellatus Say, y; No. 3048 U.S. Nat. Museum.

Plate VIII.

a
JS,
1

. Onemidophorus tessellatus melanostethus Cope; No. 3067 U. 8. Nat. Museum.

Fig. 6. Cnemidophorus variolosus Cope; No. 3060 U. §. Nat. Museuni.

Plate IX.

Fig. 7. Cnemidophorus sealineatus Linn.; No. 4878 U. S. Nat. Museum.

Fig. 8. Cnemidophorus septemvittatus Cope ; No. 2872 U. S. Nat. Museum.

Plate X.

Fig. 9. Cnemidophorus gularis gularis B. & G.; No. 3039 U. Nat. Museum.

Fig. 10. Cnemidophorus gularis scalaris Cope ; No. 8319 U. S. Nat. Museum.

52 A SYNOPSIS OF THE SPECIES OF THE GENUS CNEMIDOPHORUS.

Plate XI.

Fig. 11. Cnemidophorus scalaris sericeus Cope ; No. 3066 U. S. Nat. Museum.
Fig. 12. Cnemidophorus gularis semifasciatus Cope ; No. 9248 U. S. Nat. Museum.

Plate XT.

Color variations of Cnemidophorus tessellatus and of Cnemidophorus gularis.
A. Young of C. tessellatus (C. gracilis B. & G.); No. 9270.
B. C. tessellatus perplecus B. & G.; No. 3060.
C. C. tessellatus tessellatus Say, (2; No. 3048.
D. C. tessellatus tessellatus, 7; No. 4113.
EF. C. tessellatus tessellatus, 0; No. 3048.
FP. C. tessellatus rubidus Cope; No. 15,149.
G. C. gularis gularis ; young ; No. 14,249 ; and adolescent (sp. from Rio Grande, Capt. Livermore).
H. @. gularis gularis B. & G.; adult ; No. 3039.
I. C. gularis scalaris Cope, a; No. 14,302.
K. C. gularis scalaris Cope, 8 ; No. 8319.
L. C. gularis semifasciatus Cope ; No. 9248.

Plote XIE

Color variations of Lacerta muralis copied from Eimer.
. Lacerta muralis 3; young; from Karst.
m. campestris De Betta.
m. albwwentris Bonap.
. maculata Kimer.

SSawh
SESS
8

. tigris (reticulata) Eimer.

*D snjzeTossey “4 °O ‘g ‘“snxerdied snyvijossoy snioydoprm1euy ‘T

‘009 ‘sOllUd ‘Aewy suooOVsuB.y,

TIAX “TOA

‘I wed

‘TA 99?1d

oye Oe gees

“7 »

Transactions Amer. Philos. Soc.

Vol. XVII.

Part I.

Plate VII.

3, Cnemidophorus tessellatus tessellatus @. 4, C. t. tessellatus 7.

“SnUJOqSOUvoUL SsngyvT[esse snxoydoprureug ‘¢

"SNSO[OIIBVA *C) ‘9

ee ,

‘00 ‘SO[IUd ‘lewy suoyovsue.sy,

‘TIAX “1OA

‘I weg

THA 9981d

“snyvoul|xes snioydoprmmeuy ‘,

“snyeqgiAmeqdes “9 ‘8

‘009 ‘SOlIUd “louly suoyoesuvay,

‘TIAX “TOA

I qaBq

“XI 97810

an
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:

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‘009 ‘SOTIYd ‘19uMIy SUOTJOBSUBLY,

IT Med “WAX 1lOA

“XX 948Id

11, Cnemidophorus gularis sericeus.

Transactions Amer. Philos. Soc.

12, O. g. semifasciatus.

Vol. XVII.

Part I.

Plate XI.

"snye[[osso} snioydoprusug ‘7-WF

‘stiv[ns "9 “7-

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TIAX “1l9A

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TIX 998Id

el .
5 dats
Pa
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ae = aS = w
ae ‘

Transactions Amer. Philos. Soc. Vol. XVII. Part I. Plate XIII.

A-E, Lacerta muralis.

t
a a Saat ———_ SE Oe
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vf
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ARTICLE IV.

THE TRIBUTE ROLL OF MONTEZUMA.

EDITED BY

Dr. DANIEL G. BRINTON, Chairman,
HENRY PHILLIPS, Jr., and
Dr. J. CHESTON MORRIS,

A Committee appointed by the American Philosophical Society, November 16, 1888.

Part I.

THE WRITTEN LANGUAGE OF THE ANCIENT MEXICANS.
BY DANIEL G. BRINTON, M.D., LL.D.

There are scarcely any tribes, however rude, who do not aid their memory by
some objective device. The savage Australians have tally sticks, and in some locali-
ties depict figures on the walls of caves in honor of some important event. A hand-
ful of sticks of different lengths was the simple mnemonic device of the [roquois ;
while knots tied in strings led in Siberia and Peru to a complicated system of
thought recording.

The arts of drawing and coloring lent themselves with peculiar facility to this
purpose. They were by no means late or limited acquisitions of the human intellect.
Far back in Paleolithic times we find evident traces of them, as we also do amongst
savage peoples in every continent. The man of the mammoth and the reindeer epoch
depicted these animals with singular fidelity by scratching their outlines on bones ;
and the paint pots and masses of ochreous earth found on the sites of his dwellings
prove that he was also a colorist, though his canvas may have extended little beyond
his own skin. On this he probably drew and painted, as does the savage to-day,

A. P. S.— VOL. XVII. H.

54 THE TRIBUTE ROLL OF MONTEZUMA.

some signs or marks which designated to what clan he belonged, or of what deeds he
was proud. If his family was that of the bear, he would draw the outline of a bear ;
if he boasted of his hunting exploits, he would depict the outlines of a man spearing
an animal.

Just such devices do we find on fragments of bone and stone dating from the
Magdalenian epoch in France. They are the beginnings of recorded language, the
primitive examples of writing. In such instances of picture writing, the outline of
the bear recalled the concept, bear, and this is the utmost that any form of writing
can do.

Picture writing was familiar to almost all American tribes. It is the simplest
and first step to all stages of recorded thought ; but it is cumbrous, and inapplicable
to many ideas. We cannot directly depict what is abstract, or a general term, or a
complex conception. This deficiency led to the employment of symbolic characters.
In these, a part is taken for the whole of a picture, as a foot of a rabbit for the
rabbit itself; or the figure of the sun, the life-giver, for the abstract idea of life
both which symbols occur in the native Algonkin writing. In time, the symbol be-
came conventionalized in form, so that the connection which originally existed
between it and a concrete conception was lost from sight and memory. The
figure of forgotten origin represented an idea, and this was all that was known about
it. Thus arose ideographic writing, such as we find in singular development among
the Chinese.

Still, it will be observed, there is no relation of any of these signs to the sound
of the language. All of them—pictorial, symb olic and ideographic—bear no more
relation to the spoken word than do the Arabic numerals to us. An ideographiec text,
like an algebraic formula, can be read by all who have once been taught the mean-
ing of its elements. It is a universal language. This immense advantage is more than
counterbalanced by the enormity of the task of committing to memory the necessary
number of ideograms requisite for the purposes of life. It is said that in China at least
five thousand characters are needed to conduct a business of ordinary extent ; and that
a man of learning should be able to recognize twenty to thirty thousand. Few men
in life require a knowledge of more than three languages; while the great majority
have no use for more than one. Hence a method which represents all the concepts
in a language by the combination of thirty or forty characters is incaleulably more
time-saving, and therefore better for the vastly greater number, than one which
demands thousands of characters.

This obvious advantage made itself felt early in the history of writing. The
most ancient Pyramid texts of Heypt, the oldest Cuneiform of Syria, indicate the

THE TRIBUTE ROLL OF MONTEZUMA. 55

effort of the human mind to seek a way out of the cumbrous fetters of thought-
writing into a freer air, by having the sign no longer refer to the thing or the thought
but to the sound, the spoken word.

These general remarks are not out of place in this connection; they are in fact
necessary, for the method of writing developed by the ancient Mexicans, in the stage
in which it existed at the time of their subjection by the Huropeans, embodied, curi-
ously enough, every one of these elements, pictures, symbols, ideograms and phonetic
signs; and it is only by keeping this fact constantly in mind, and by seeking to ren-
der each according to the special system which it represents, can we hope ever to
untangle the labyrinth of the Aztec codices.

It is because this essential fact has been overlooked that the syllabaries and lists
_ of Mexican hieroglyphs hitherto published have proved almost worthless for the
decipherment of the manuscripts which have been preserved. It must also be ob-
served that the same sign may have a phonetic value in one place, and a purely ideo-
graphic in another; and it would be obviously absurd for any scholar to attempt the
construction of such a syllabary unless he is familiar with the sounds of the Nahuatl
as a spoken tongue. Otherwise the phonetic elements would escape him.

The presence of all these various methods of writing in the same document can
readily be demonstrated. No one will question that in the tribute rolls, such as the -
Codex Mendoza, published in Lord Kingborough’s collection, the picture of a
feathered coat, or some such definite object, followed by the well-known signs of
the numerals, means that a certain number of such articles were due from a certain
district. Here the coat is in picture writing, while the numerals are ideograms.
Again, where in the year signs, the rabbit, tochtli, is represented by his head only,
we have a symbol.

There has been no dispute among students of Mexican hieroglyphs that signs of
these several characters occur; but when it comes to the alleged presence of purely
phonetic elements, the divergence of opinion has been considerable. Some writers
have claimed that a large proportion of the figures refer to sounds rather than
thoughts, while others have gone so far as to deny all evidence of phoneticism in the
codices.

‘Much of this discrepancy has arisen from the tendency of students of the latter
class to look in the Mexican writing for an alphabet, like that to which we are accus-
tomed. Nothing of this kind existed, or could exist in the stage to which the
Aztecs had developed their plan of recording thought. The material out of which
an alphabet might have evolved was indeed present, but it was submerged in much

extraneous and traditional rubbish.

56 THE TRIBUTE ROLL OF MONTEZUMA.

The line of research which I believe will give us the clue to a correct interpreta-
tion of the phonetic elements in the Mexican codices I have set forth and exemplified
with a number of illustrations in some articles published several years ago and col-
lectively republished in my “Hssays of an Americanist” (Philadelphia, 1890). A
brief statement of the method there advanced may appropriately be introduced here.

It is agreed among those who have most carefully studied the subject that there
is but one path by which the human mind could have originally proceeded from ideo-
graphic or thought writing to phonetic or sound writing. This was through the
existence of homophones and homoiophones, that is, of words with different meanings
but the same or nearly the same sound. The same sign would come to represent two
different ideas, not that it represented them both pictorially, but because both were
expressed in the language by the same sound. This is the seeret of the first intro-
duction of the element of sound into writing.

An illustration of this may be offered from the Heyptian writing in its early
stage. The word nefer meant a lute, and in the early texts when the writer wished
to convey the idea of a lute he simply drew the picture of one, and all understood it
and read it nefer. But this sound nefer had in Egyptian another meaning, which
was “door;” just as in English the sound Juée has also the meaning booty or plunder
(loot). It was discovered therefore that by reference to sound the picture of a lute
could also stand for “door” and thus save the trouble of having a separate sign for
that concept. Proceeding on this line the same figure would come to be employed
for a number of ideas expressed in the spoken tongue by the same or closely similar
sounds; as in fact the sign of the lute in Egypt came to signify not only a lute ora
door, but a soldier, a colt and the adjective “ good.”

When the word thus represented was a monosyllable, the sign for its sound
would apply not only to it but also to all words in the language where this syllable
occurred; and thus a syllabic alphabet began to be developed. Again, when this
monosyllable coincided with one of the phonetic radicals of the language, that is,
with one of the letters of its natural alphabet, we perceive the beginning of the true
alphabetic writing. A simple example of this would be in English the picture of a
bee, which in sound represents the second letter of the English alphabet.

The discussion of these distinctions is not irrelevant to the present theme. On the
contrary, the student must have them constantly in mind, for as he investigates the
phonetic elements of the Mexican codices, he will] find that sometimes they represent
the whole of a polysyllabie word, at other times a syllable only, and more rarely, that
a true phonetic radical had been evolved and was employed just as we employ a let-
ter of our alphabet in writing a word. I believe it may be averred with safety that

THE TRIBUTE ROLL OF MONTEZUMA. 57

of the five vowels and fourteen consonants which make up the Nahuatl alphabet,
three vowels and three consonants had reached the stage where they were treated as
true letters. The vowels were a for which the sign was borrowed from the term adi,
water in composition a ; e was represented by a bean, edd, in composition e; and o by
a footprint or path, oti. The consonants were p, represented by a flag, pan, or a
mat, petl; t by a stone, fetl, or the lips, tentli; and z by a lancet, zo. As in the case
of p and ¢, several signs were employed for the same sound, no uniformity having
been established in this respect. This is especially true for the syllabic characters,
where there was a still wider range of variation, much depending on the caprice or
the habit of the scribe.

These variants offer difficulties enough to the student; but they are light
compared to what is further in store for him.

When the whole name of an object or most of it was used as a phonetic value,
and several such pictures representing sounds are brought together to form a sentence
or compound word, the script remains truly phonetic, but becomes a regular puzzle,
in all respects of the character of that which we call a Rebus.

This principle is also that which is seen in the “canting arms” of medizeval her-
aldry, and is at the basis of most of that play upon words which we call “ punning.” -
So far as I am aware, there is no term in science which serves to express it, and for
this reason in the articles above referred to I gave it the name zkonomatic writing,
that is, a method of writing by means of the names of the figures or objects repre-
sented. Jt resembles in appearance, but differs radically in principle, from picture
writing, for although it is composed of pictures, these in ikonomatic writing are used
solely with reference to the sound of their names, and not with any relation to the
objects which they portray.

Since my publications on this subject, Dr. Morris Jastrow, Jr., has called atten-
tion to a number of examples probably of the same character, in Assyrian inscrip-
tions ; and it would appear to have been one of the stadia through which human art
passed in its efforts to develop a true alphabet. Its undoubted presence and exten-
sive employment in the Mexican system of writing [ have abundantly shown in the
articles to which I would refer the reader who would desire further evidence.

While it is my conviction that the above principles, judiciously applied, will
result in the decipherment of the ancient records of the Nahuas, such as that which
is here presented, all who are conversant with the subject will acknowledge the pro-
priety of calling to our aid the widest range of comparisons possible before proceed-
ing to the interpretation of a particular manuscript. The mass of unexcelled mate-
rial for this study which was originally collected by Boturini, and which through

58 THE TRIBUTE ROLL OF MONTEZUMA.

many perils is at last in a fair way to be rendered accessible to the scientific world,
will add so much to our knowledge that it would be time lost to seek definite conclu-
sions from the fragment here presented. The object of the Society which publishes
it is accomplished when this testimony to a past culture is thus laid before the
students of human development with such brief words of introduction.

or
oO

TILE TRIBUTE ROLI. OF MONTEZUMA.

Part IT.
THE TRIBUTE ROLL OF MONTEZUMA.
BY HENRY PHILLIPS, JR.

The manuscripts here reproduced came into the possession of the American
Philosophical Society in the year 1830, having been presented, together with about
twenty-five hundred objects of Mexican antiquities, by Hon. Joel R. Poinsett, who
had been Minister of the United States at Mexico.

The colored pictures will be found engraved [uncolored] in Lorenzana’s Historia
de Nueva* Espana, Mexico, 1770. They are numbered in that work respectively as
1, 2, 27, 28 and 30, and are designated as the catalog of the tributes paid to Monte-
zuma, their amounts and species and the peoples by whom they were paid.

The tributes as paid consist of various manners of dresses, military and civil,
arms, banners, etc., cotton, gums and spices, ornamented vestments and other arti-
cles, [even as it is said, lice and ants], precious stones, apparently cut, and necklaces
of similar objects.

The pictures now presented will be found absolutely correct. Upon comparison :
with those in Lorenzana it will be seen that there are many discrepancies in form,
shape, size and position; that in the printed volume some written matter is inter-
polated as explanations on the plates, and in other cases there are inscriptions omitted
from the roll. The plates represent the tributes paid by Tlateluleo (Pl. 1), Tepetlap-
lalco (Pl. 2), Tlauhquitepee (27), Tuxpa (28), Tazco (30) and others.

Part IIT.

PHYSICAL AND ETHNOGRAPHICAL CHARACTERISTICS.

BY DR. J. CHESTON MORRIS.

The fragments of the tribute roll are four in number, those of the calendar, two.
They are all of maguey paper, made from the fibre of the Agave americana by a very
simple process: A section of the stem is shaved or cut so as to give a long thin
strip which is macerated and rolled into the required density, texture, smoothness
and thickness; in this case the width of the sheet was between eight and eight

* Cordillera de los Pueblos que antes de la conquista pagaban tributo & el Emperador Muctezuma yen que especie
y cantidad.

60 THE TRIBUTE ROLL OF MONTEZUMA.

and a half inches. For the tribute roll a greater width was obtained by placing
strips of two and a half inches wide on one side, while still moist, and causing them
to be rolled or pressed into imperfect unity with the main strip; or, as in No. 4, by
similarly uniting two sheets of full width and cutting off the edges. They then
seem to have been cut into pages of seventeen inches long for the tribute roll. The
outlines of all the figures have been carefully made with an ink resembling sepia, and
then the various colors, probably of vegetable origin, filled in. These are shaded
with much accuracy.

The ethnographic features of the pictures are very interesting and suggestive.
Thus on No. 2, Tlatilulco, are four heads each surrounded with a very light yellow
circlet rising into a point above, and fastened with a red bow or sash behind; the
face is white with slight pink hue, the nose straight and pointed, eyes black, as also
the long hair which covers the ears; the expression is that of command. Very
different is the head on No. 30, near the foot of the page, the face of which is of a
yellowish color, the hair represented as twisted in two coils which are intertwined
around the head and terminate in horn-like projection above the rather high forehead,
while the nose is aquiline, almost gibbous, with thick lips and prominent chin.

On the first of the two calendar sheets we see two heads without color, but sur-
mounted by what may represent a cap or helmet with two horns; then a face which
recalls in its outline those of the first fragment of the tribute roll. Then follow
others, nearly all with very long straight noses, some of them however slightly gib-
bous. About midway on this sheet (which is forty-two inches long) is a representa-
tion of two square huts or houses, with roofs rising to a flat peak in the centre; in
the line below that of a man seated in a curule chair, wearing a sombrero and plaited
doublet, with a long straight sword held in front of his left hand. It would seem
as though this were a narrative which was soon after abruptly terminated, as the
illustrations above the circles which I take to stand for days are only three in number.
It is worth noting that the faces are all turned in reverse directions in the alternate
lines, thus making them advance first from left to right, and in the line below from
right to left. The circles indicating days are usually ten in each row, sometimes
eleven, once nine. Some bear a svastica symbol and are colored red; others at irreg-
ular intervals have a red face, with a gibbous pointed nose and very full lips, partly
filling a white circle not concentric with the main one, which is otherwise always
yellow. I believe these faces represent the phases of the moon.

The other calendar fragment, which is thirty-two inches long, is of inferior
workmanship, has the day circles (some of which are colorless, others green and
ereenish yellow) arranged on the right side. On this again, near the lower end, is

THE TRIBUTE ROLL’ OF MONTEZUMA. 61

seen the Spaniard, with long thin features, seated in his curule chair and carrying his
two-handed sword, while on the last line are represented three figures with hats
having doubly curved rims and full bonnet-like crowns, the first seated in the curule
chair holding the sword resting on its point; they all have thin beards, and the two
others look as though advancing on a march of exploration.

The Nahuatl words look as if made by a pencil, style, or short brush similar to
that used in delineating the figures, and with a sepia-like preparation; while the
Spanish ones have evidently been made with an ink containing iron, and an instru-
ment which disturbed the gloss of the paper, as is shown by its penetration to fibres
adjacent, giving the lines a sort of hazy margin occasionally.

SORES TORRE PTR TE Ts 2 tS

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Transactions American Philosophical Society. New Series.

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ARTICLE V.

THE SAPROLEGNIACEA OF THE UNITED STATES, WITH NOTES ON
OTHER SPECIES.

BY JAMES ELLIS HUMPHREY, SC.D.

Read before the American Philosophical Society, November 18, 1892.

In spite of the attention which most families of Thallophytes have received in |
the United States during recent years, the aquatic fungi have been hardly noticed.
Although their resemblances to the Algze on one hand, and to the Fungi on the other,
give to their study peculiar interest, it is perhaps to this twofold affinity that the
neglect is due. Their habitat is not such as is explored by the student of fungi, and
the phycologist passes them by as not of his group.

The following pages contain the results of studies of American Saprolegniacec,
earried on during the past two years in the intervals of other botanical work. The
materials on which they are based have been largely procured by myself in and
about Amherst, Mass. ; but I have to thank the kindness of friends and correspondents
in other parts of the country for considerable material illustrative of the Saprolegnia-
ceous flora of their respective sections. Of these, I am indebted to Dr. Ida A.
Keller, of Bryn Mawr College, for cultures from the neighborhood of Philadelphia, and
for a single one from Kentucky; to Rey. A. B. Langlois, of St. Martinville, Louisi-
ana, for cultures from that:vicinity; to Prof. G. F. Atkinson, formerly of Auburn,
Alabama, and to Mr. J. M. White, of Agricultural College, Mississippi, for speci-
mens from those localities. I am also under especial obligations to Prof. William
Trelease, of the Missouri Botanic Garden, at St. Louis, who has most generously
placed in my hands without restriction all the preparations, notes and drawings made
during his too brief study of the family, carried on chiefly in eastern Massachusetts

Doren. VOlay. SoVillenl.

64. THE SAPROLEGNIACEZ OF THE UNITED STATES,

in 1881. I am also indebted to Prof. Roland Thaxter, of Harvard University, for
specimens from Mt. Washington; and I owe to Mr. A. B. Seymour, of Harvard
University, references to the few published exsiccatw of this family and the exami-
nation of one of them. The others I have not been able to examine.

While neither the amount of material examined, nor the variety of sources from
which it has been drawn, can justify any generalizations, they yet afford a basis for
some preliminary ideas concerning the distribution and relative abundance of some
of our species. The material has also been utilized, in part, for the study of several
questions relating to the morphology of the group, on which it is hoped to shed some
light. Physiological questions have not reccived the attention which they deserve,
and which it is hoped to give them in future studies. Their discussion is, therefore,
restricted as much as possible in the present paper, which is concerned chiefly with
the morphological and systematic aspects of the family.

A pretty careful review of the literature has led to some conclusions concerning
the synonymy of certain species not yet known to be American which have not
previously been suggested. Therefore, it has been thought worth while to include
in the systematic account of the family all published names, with an indication
of the standing of each, so far as it can be determined from available data.

The appended bibliography makes no pretensions to completeness, but it is
believed to contain the titles of all works of present value, or of much historical
interest, relating to the morphology and classification of the Saprolegniacew, as well
as those of certain other papers which are quoted in the following pages. Papers
by American authors are marked with a dagger (+). The titles of the few papers
included which I have not been able to examine are preceded by an asterisk (*).
For access to many of the remainder I am indebted to the various libraries in
Amherst, Boston and Cambridge, and to Prof. W. G. Farlow, of Harvard
University. Hach of the works is cited in the body of the paper by its abbreviated
date, which is prefixed to its full title in the list. This method has the advantage of
doing away with cumbersome footnotes, and of giving, in the briefest possible form,
the date of the work with the reference to it. The last point is one of much con-
venience and economy in the citation of synonymy.

WITH NOTES ON OTHER SPECIES. 65

INTRODUCTORY.

The greater simplicity or apparent primitiveness of structure which is usually
associated, among the simplest plants, with life in the water, together with the fact
that various theoretical considerations point to the water as the probable habitat of
the earliest forms of life, lends to the study of the aquatic Thallophytes the highest
interest. Leaving out of consideration the natural and fairly circumscribed group
of the Schizophyta, the great body of these forms is made up of plants containing
chlorophyll, belonging to the algal stock, and presenting various lines of relationship
and descent. From this stock must undoubtedly have been derived the great
collateral chlorophyll-less groups of fungi. Most of the latter have been so modified
to meet the conditions of aérial life, that the absence of chlorophyll has become
of minor importance as a distinguishing character. A few, however, which cling to
the ancestral habitat have preserved so many of the essential algal features that
it becomes difficult to separate them from the Algwe except on the basis of
their acquired saprophytic or parasitic habit and consequent loss of chlorophyll.

All of the characteristically aquatic groups of fungi belong to the most
primitive or alga-like division—the Phycomycetes—and they are all probably
to be regarded as primitively aquatic. Several interesting cases of transition
from aquatic to aérial life are, however, presented by species immediately related
to some aquatic ones and referrible to natural groups which may, in general,
be called aquatic. The aquatic Phycomycetes may be grouped under five heads,
as follows:

1. Chytridiacee. 4, Saprolegniacee.
2. Ancylistacee. 5. Pythium.
3. Monoblepharidacee.

The Chytridiacee constitute a heterogeneous group of considerable size and
of much variety of structure. Its members are regarded by some writers as the
most primitive of the fungi, and by others as degenerate forms derived from
the higher Phycomycetes. They possess a very rudimentary mycelium or none
at all, and commonly produce both sporangia, with zodspores, and resting spores.
An evident conjugation precedes the formation of resting spores in a very
few cases; but, for the most part, the group presents no traces of sexuality.
A considerable number of the species are parasitic upon terrestrial Phanerogams,
usually such as grow in wet places; but the aquatic species constitute the larger part
of the group and are also chiefly parasites. Their hosts include Protozoa, Anguil-
lule and Fotifera ; Saprolegniacew, Alge of every group, various spores and pollen

66 THE SAPROLEGNIACEZ OF THE UNITED STATES,

grains ; in short, a large part of the minuter organisms of fresh waters, to which they
are chiefly restricted. A few species, however, are marine.

The Ancylistacee include a few species, chiefly parasitic upon Conjugate and
Anguillule. The young plant is mycelium-like, but is entirely consumed in the
formation of the reproductive organs. These are sporangia, oogonia, and antheridia.
From the union of the protoplasm of the last two, there results in each case a single
odspore. While clearly related in their vegetative structure and habits with
the Chytridiacee, these plants may be regarded as forming, in their reproductive
organs, a transition to the higher Oomycetes.

The Saprolegniacee are to be discussed later.

Closely related to them, but differing in essential particulars, is the single genus
Monoblepharis which forms the type of a distinct family. It has been studied only
by Cornu, who has described three species. According to this author, the plants
have sporangia with uniciliate zojspores; and the odspheres, formed singly in the
odgonia, are fertilized by motile uniciliate antherozoids, produced in a cell cut off just
below the odjgonium from its supporting filament, which gains access to the odsphere
through an opening at the apex of the ojgonium. These plants are saprophytes.

The Peronosporacee are represented among aquatic fungi by some of the mem-
bers of a single genus, Pythium. Like the rest of the family, the members of this
genus have an abundant mycelium from which are developed the sexual organs,
antheridia and odgonia. Hach of the latter produces a single odsphere from a portion
of its protoplasm, the rest remaining as “ periplasm,” and ultimately forming an outer
coat about the spore. There appears to be an actual passage of protoplasmic
substance from the antheridium to the oisphere, constituting a real act of fertilization.
In Pythium, as in some of the Ancylistacec, the zoispores are formed outside of the
mouth of the sporangium from the contents of the latter, after it has been extruded
ina single mass. The aquatic species of the genus are parasitic on water plants or
saprophytic on organic remains. One or more species attack terrestrial Phanero-
gams.

The American literature of these various groups is confined to a few scattered
notes in addition to that quoted in the present paper, with the exception of Prof.
Farlow’s account of the genus Synchytrium of the Chytridiacee. Its members are,
however, not aquatic.

This brief preliminary account may suflice to indicate the near relationship of all
the aquatic fungi and to suggest the great morphological interest which attaches to
them; while it may suitably preface the detailed discussion of the family which
forms the subject of the present contribution.

WITH NOTES ON OTHER SPECIES. 67

SAPROLEGNIACH A.

The vegetative organs of these plants consist of usually branched tubular fila-
ments without dividing walls, and therefore with a single continuous cavity. The
filaments are of two sorts—the internal threads, which penetrate the substratum,
branching freely, and tapering rapidly to their pointed ends (Fig. 2), and the external
ones, which arise from the latter and radiate outward into the surrounding medium
(Fig. 1). The following description refers chiefly to the latter.

In general, there are no sudden changes in the calibre of a filament, but only a
gradual decrease from one end to the other; but the Leptomitee are characterized by
abrupt constrictions at intervals, marking off the hyphze into segments, but not
completely closing the cayity (Fig. 6). The hyphe are usually largest at their
bases; that is, where they arise from or give rise to threads of the other kind.
From this point the external threads decrease slowly in size. Those of Zeptomitus,
however, decrease abruptly with each successive branching, so that their apical seg-
ments become reduced to an eighth of the diameter of the basal ones. The different
species present very wide extremes in the size of their filaments, whose diameter may.
vary from 5, in Aphanomyces to more than 100, in S. Treleaseana. The length of
the filaments in any given species or individual is considerably affected by the
amount of available nourishment; but in vigorous specimens of Aphanomyces it
may not exceed two or three millimeters, while in some Achlye it may reach more
than twenty millimeters.

The hyphal walls of the members of this family are composed, unlike those of
almost all other fungi, of unmodified cellulose, which reacts readily and charac-
teristicaliy with chloroiodide of zine. Within this wall is a layer of protoplasm which
lines it closely and forms a hollow cylinder. At the centre is a wide vacuolar space,
across which run, especially in the younger parts of the filament, strings of proto-
plasm connecting opposite parts of the parietal layer. This layer is densest and
most granular in the youngest or apical part of the filament, and in the older parts
the granular protoplasm forms a network of anastomosing threads or bands, with
somewhat. wide interstices (Fig. 4). In the threads of this network a constant
circulation is kept up, towards the base in some and towards the apex of the hypha
in others. It is worthy of remark that when young threads are cut off in water their
death does not necessarily result. Very little protoplasm is lost from the tube thus
opened, but a new cellulose wall is very quickly formed across the cut end (Fig. 3),
and the hypha remains capable of normal development if nourishment be again sup-

68 THE SAPROLEGNIACEA OF THE UNITED STATES,

plied, or even of developing until its protoplasm is exhausted, without further nour-
ishment.

Scattered through the protoplasm without order, but commonest at the nodes
of the granular network, are the nuclei, normally ellipsoidal in form, and each with a
distinct central mass which stains more deeply than the rest of the nucleus (Fig. 4).
These central masses have been generally termed nucleoli, but they seem clearly to
correspond rather with the chromatin bodies of more highly organized nuclei, and
will, therefore, be better designated as chromatin-masses. Between the chromatin-
mass and the nuclear membrane is a considerable space occupied by a substance
which stains very slightly with hematoxylin. The nuclei are most abundant in the
young parts of the hypha, where the protoplasm is densest. They increase in num-
ber, with the apical growth of the thread, by fission. The division of the nucleus is
preceded by the division of the chromatin-mass, and commonly occurs in a plane at
right angles to its long axis (Fig. 5). I have observed some eases, like one shown
in Fig. 4, where two nuclei lie close together, with their long axes parallel, but have
never seen preliminary stages to convince me that they haye resulted from the
division of a nucleus in the plane of its long axis. Hartog states (’89) that he has
observed karyokinetic phenomena in some cases, but I have been unable to find
evidence of any other than direct division.

The growth of the hyphe takes place at their blunt or somewhat pointed tips.
Data as to the rate of growth are very few. Pringsheim (’51) reports a rate of
400, (= .4 mm.) per hour in a new filament of Saprolegnia, growing into an emptied
sporangium. Hine (’78) records having observed a growth of 70 to 90, per hour
during three hours’ observation of a filament of Saprolegnia ; and I have measured a
growth of about 100, per hour in a vigorous hypha of Aphanomyces, while the germ-
tube from a zodspore of the same species grew at the rate of about 40, per hour in
water.

The purely vegetative branching of the hyphe is sometimes dichotomous at the
principal divisions of the larger ones, but commonly of the monopodial type in the
small branches. In most species the branches may arise from any point and develop
by apical growth at acute or right angles with the main axis. In the genus Leptometus,
as here limited, branches arise only from the acroscopic ends of the segments, close
to the origins of the next segments of the axial series (Fig. 6). They are separated
by constrictions from their parent segments; but when the segment next below a
sporangium gives rise to a branch, it grows out for a short distance without con-
striction, and then produces a new segment (Fig. 116), as Pringsheim has pointed
out (’60).

WITH NOTES ON OTHER SPECIES. 69

The internal hyphe, whose office is the absorption of nourishment from the sub-
stratum, may properly be termed rhzzozds, whether from a morphological or a physio-
logical point of view. DeBary states (81, p. 95) that the external hyphe may send

~ down rhizoidal branches which penetrate the substratum. Well-developed threads,

when cut off from their basal portions and brought in contact with fresh nourishment,
will attach themselves to it by new rhizoids and continue their growth.

In addition to the protoplasmic contents and the food material diffused through
it, the hyphe of the Saprolegniacee contain more or less generally certain bodies as
yet unrecognized in other plants. They have been called by Pringsheim (’83 5),
cellulin granules (Fig. 6, c). They occur in the filaments or in reproductive organs
formed from them, as discoid or lobed bodies, those of the latter form arising by
fusion of several disks. When young, they are homogeneous and rather strongly
refractive ; and when old they often become distinctly stratified. They are, perhaps,
most abundant and conspicuous in Leptonitus lacteus, where they were early
described by Pringsheim (’60) as nuclei. In this species they often become lodged
in the constrictions of the hyphe and may completely close the passage. Prings-
heim has shown (’83 6), that the substance of these bodies is neither a proteid nor a
carbohydrate, although it is in some respects related to cellulose and starch. He.
regarded them as waste products of metabolism rather than as reserve materials,
since he saw no evidence of their solution or transformation. But Rothert has shown
(88) that they probably contribute to the formation of the separating wall of the
sporangium, since they seem to disappear during that process. It may also be
suggested that cut hyphe may owe their power of promptly repairing injury to the
presence of this material. Should this be shown to be the case, they may be regarded
as a soluble form of cellulose available for use in forming and repairing cellulose walls.

NOn-SEXUAL REPRODUCTION.

After they have become well grown, the external hyphz begin to produce the
organs of reproduction, which are of two sorts, sexual and non-sexual. We will con-
sider these as they are developed in the order of time, examining first those of non-
sexual or vegetative reproduction. Only a single organ of this sort is common to
the entire family ; namely, the zoosporangvum. Within this organ are produced the
agents of the rapid propagation of the species concerned, the zoospores. The phe-
nomena of the development and individualization of the zoispores within the
sporangium appear to be essentially the same in most of the genera, at least. But
the manner of their release from the sporangium and their subsequent history

70 THE SAPROLEGNIACE4# OF THE UNITED STATES,

undergo various modifications so characteristic and so related to each other that
they furnish the basis for the grouping of the species into a natural series of genera.
We pass to a detailed examination of their production and fate.

The first account to give an approximately correct description of these phenomena
was that of Hannover (’42), followed by that of Unger (43). Subsequently Prings-
heim (51) and DeBary (’52) extended their observations, and the subject has been a
favorite one down to the present. The formation of a sporangium begins with the
gradual cessation of the apical growth of a filament. Now commences an accumula-
tion of protoplasm in the terminal portion of the filament, which usually becomes
more or less swollen. No increase in size occurs, however, in the hyphex of
Aphanomyces. Finally the end of the hypha is filled with a very dense mass
of protoplasm with numerous nuclei, which passes rather abruptly into the thin proto-
plasm of the lower part. In the narrow intermediate region between the dense and
the thin protoplasm, is formed a clear disk of hyaloplasm, seen as a band in lateral
view. Its hyaline character is due to the withdrawal of the microsomes from the
originally granular protoplasm of that region. Across the lower surface of this disk
is developed a cellulose wall, beginning at the wall of the hypha as a ring and pro-
gressing rapidly inward from all sides until the central opening is closed, and a solid
wall separates the terminal portion of the thread, as a sporangium, from the remain-
der. It has been said that this basal wall of the sporangium is different chemically
from the other cell walls of the plant. Not only is this improbable a prvorz, especially
in view of its common fate in Saprolegnia, but careful examination shows that it
reacts like the other walls with chloroiodide of zinc. As before remarked, Rothert
(788) has observed the occurrence of abundant cellulin granules in the region of the
forming wall. Later these cannot be recognized and he suggests that they may
furnish material for the wall. The hyaloplasm which thus at first lines the spo-
rangial surface of this wall soon becomes again granular by the return of its micro-
somes.

The sporangium thus formed was regarded by earlier writers—Naegeli (47) and
others—as a free cell enclosed in the end of the filament. It differs widely in form
in the different species, and even considerably in the same species. Commonly it is
approximately cylindrical, and may be swollen most at its apical end (Saprolegnia),
or in the middle (Achlya), with a length from six to twelve times its greatest
diameter. In Pythiopsis, Thraustotheca and Apodachlya pyrifera, the length is so
reduced that it becomes short-clayate or pyriform; and in some sporangia of
Pythiopsis and in Apodachlya brachynema, the form is quite globular. These con-
tracted forms occur also among more typical ones in S. forulosa. On the other hand,

WITH NOTES ON OTHER SPECIES. oo

the sporangia of Aphanomyces often reach a length of more than a hundred times
their diameter.

In rare cases, the quantity of protoplasm contained in the sporangium may be
sufficient to completely fill it, but usually it forms a parietal layer of greater or less
thickness, with a vacuolar space extending through the middle. If this layer be very
thin, or if the sporangium be completely filled, that condition will induce certain
modifications in the usual course of development of the zodspores, but in a great
majority of cases the process is as follows. In consequence of the greater turgidity
of the sporangium than of the lower part of its hypha, its basal wall becomes convex
towards the base of the filament (Fig. 7, a). The first indications of the formation of
zodspores then soon follow. The phenomena attending this process have been the
subject of much study and of widely different interpretations, most of which cannot
profitably be detailed here. The most important contributions to the discussion
have been those by Strasburger (’80), Biisgen (’82), Ward (’83), Berthold (’86),
Hartog (’87), and Rothert (’88) ; and their papers may be consulted for the details of
the various views put forth. Repeated studies of several species have satisfied me
that Rothert’s account, which is corroborated in most details by Berthold and
Hartog, is practically correct. Therefore the following account is a combination -
of the descriptions given by those writers with personal observations. The descrip-
tion may best be based, as has been said, on the commonest form of sporangium,
that with a parietal laver of protoplasm of considerable thickness and an axial
vacuole. At first, irregular rifts begin to appear in the protoplasm, extending out-
ward from the vacuole. They soon become more definite and more numerous, and
connect with each other in such fashion that the protoplasm is marked off into a
number of irregularly polygonal masses, as seen from the surface (Fig. 7, a). It is
probable that the number of these blocks, which finally become spores, corresponds
to the number of nuclei originally shut in by the basal wall, since the zodspores are
always uninucleate, and there is no evidence that any nuclear division occurs within
the sporangium. The clefts are at first quite narrow, and the protoplasmic masses,
or “spore origins,” as they have been called, are frequently connected by threads of
protoplasm. The somewhat irregular outlines and the granular structure of the
origins, together with the appearance of the connecting threads in surface view, have
led Strasburger, Biisgen and Ward to very different interpretations of these clefts
from those here adopted. They have regarded them as “ cell-plates,” separating the
spores, and consisting of layers—lines in optical section—of granules. But it is

FAG Se VOI. SX VAL. Jie

72 THE SAPROLEGNIACEZ OF THE UNITED STATES,

clear that Rothert’s explanation is the correct one, since, as the clefts broaden, the
granules disappear, or separate with the origins.

At about the same time, with the appearance of the first signs of the segregation
of the spore origins, there is formed, if the sporangium belong to a species of Achlya
or Saprolegnia, normally at its apex, an outgrowth or papilla, from whose tip the
zoospores will finally escape. Its formation begins with the accumulation at that
point of a mass of hyaloplasm which presses the wall outward. After its formation,
the hyaloplasm becomes granular, except a thin layer which remains intimately con-
nected with the apex of the papilla (Fig. 7, a). This apical wall is always less
sharply defined and more highly refractive than any other part of the sporangial
wall, and these characteristics become more and more prominent until the escape of
the spores.

The clefts between the spore origins rapidly widen and deepen, causing the con-
necting threads to become broken and withdrawn into the bodies of the origins. In
view of subsequent changes, and of what seems the most reasonable explanation of
them, it does not appear probable that the clefts extend at once completely to the
outer wall, although it is often very difficult or even impossible to detect with high
powers and excellent material any protoplasmic lining of the wall at this stage, when
the spore origins are most widely separated. Another good reason for believing that
the origins are still connected by a delicate parietal lining may be found in the fact
that the whole surface of an origin next to the wall remains closely applied to it
throughout this stage, and does not become rounded off at the corners, as happens
on the other sides of the origin, and on this side at a later stage.

After the separation of the spore origins has become nearly complete, there fol-
lows suddenly and without warning the so-called “homogeneous” stage of Biisgen,
the “stage of swelling of the spores” of Rothert. The spaces between the spore
origins disappear by the apparent swelling up and fusion of the separate origins, and
the contents of the sporangium appear less opaque and less granular than before. In
spots corresponding approximately to the middles of the spore origins are to be seen
clear, bright spots, and throughout the whole protoplasm are numerous vacuoles
which appear and disappear, shifting about rapidly (Fig. 7, 6). At the same time
with the beginning of this stage, there is a very sudden decrease of turgidity in the
sporangium, which is shown by the flattening of the terminal wall of the apical
papilla, previously convex outward, and by a complete change in position of the basal
wall (Fig. 7, 6). This wall has been until now, as before stated, convex downward,
on account of the greater turgidity of the sporangium than of the lower part of its
hypha. These relations evidently now become reversed, for the wall suddenly

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WITH NOTES ON OTHER: SPECIES. 73

becomes convex upward, indicating a marked and instantaneous loss of turgescence
by the sporangium. All the characteristic phenomena of this stage are much more
strongly marked in the species of Achlya (A. Americana and racemosa) than in those
of Saprolegnia (\S. ferax and sp. indet.) which I have studied. The change may
come over a whole sporangium simultaneously, so far as the eye can detect, or it may
begin at either end and extend, wavelike, to the other in two or three seconds.
While the spore origins seem ordinarily to be quite fused together, careful examina-
tion will not seldom show; here and there in the protoplasm, narrow cracks which are
the remnants of separating clefts not quite completely closed by the swelling of the
origins. Rothert’s explanation of this phenomenon seems to accord well with the ob-
served facts and with what we know of cell structure in general. He believes that,
until the beginning of the stage of swelling, the sporangium wall is lined by a contin-
uous protoplasmic layer, and therefore, as in living cells generally, there can be no
transfer of liquids between the cavity of the sporangium and the surrounding water.
The final extension of some of the dividing clefts between the origins to the wall
breaks the continuity of this “primordial utricle,” and there is an escape of fluid
through the pervious wall and a consequent loss of turgidity. This fluid is distinctly
attractive to some forms of Bacteria which may be present in the surrounding water
and is, doubtless, the cell sap. Its loss is due, Rothert thinks, to the contraction of
the walls which have been distended by their dense lining, but now become free to
assume their natural positions. Measurements show a reduction in the volume of the
sporangium amounting in some cases to as much as thirteen per cent. After this
loss, water is probably taken up by endosmose, and the mixture of cell sap and water
in the cavity of the sporangium is absorbed by the spore origins, whose bulk is so
increased that the separating spaces are practically obliterated. The successive
absorption and expulsion of this fluid gives rise to the shifting vacuoles. My obser-
vation that sometimes in S. ferax the swelling of the spore origins begins perceptibly
later than the incurving of the basal wall, distinctly corroborates this view.

A very few minutes after the swelling up of the origins, the vacuoles disappear,
and the granular appearance returns. They begin again to contract, separating
from each other on the old lines, as consecutive observation always shows. The
contraction goes on rather rapidly, and the masses become definitely separated as
independent spores. While this contraction is going on, small portions of proto-
plasm may become cut off from the different spores; but each is soon taken up, as a
rule, by the same spore to which it originally belonged. The significance of this
phenomenon will be discussed in connection with the sexual spores, during whose
formation it also occurs. - The gaps between the spores are widened by their contrac-

74 THE SAPROLEGNIACE OF THE UNITED STATES,

tion and the rounding of all their corners so that they come to lie nearly or quite free
from one another. In Achlya racemosa, and perhaps in some other species, the con-
traction is much less pronounced than is usual, and its spores do not commonly
appear distinctly separate in the sporangium.

Up to this point our account may apply equally to all the species that have
been carefully studied. But we must now distinguish between those genera whose
spores normally escape from the apex of the sporangium and those of which this is
not true. In those of the former class (Achlya, Saprolegnia, and allied genera), there
may often be seen some spontaneous movement among the spores, especially among
those near the tip. In case of the two genera just named, the apical papilla becomes
markedly more transparent and less sharply outlined, as to its terminal wall. As the
spores acquire more exactly their ultimate form, the motion increases and the termi-
nal wall fades out until it is ruptured, and the spores rush through the opening (Fig.
8). Sometimes the wall seems to soften gradually until it yields to pressure from
within ; or again, the spore nearest the apex may be seen to enter the papilla and
apparently to force its way through the partly softened wall, thus making an opening
through which the rest rapidly follow. Other modes by which the opening is made
have been detailed by Rothert (’88), but need not be further discussed here.

Some figures concerning the rapidity of the development of the zodspores have
been given by others, and I have made notes of the process in the four species chiefly
studied. Ward (’83) gives some observations on A. De Baryana (‘“ polyandra”)
and A. wpiculata, and these accord with my own on A. Americana and racemosa as
closely as could be expected. There is considerable variation in the time occupied,
depending on the age and vigor of the culture, and doubtless on various undetermined
conditions. A general statement may, however, be based on the data at hand. The
first appearance of the clefts, which mark the beginning of the formation of the
zodspores, usually occurs twenty or thirty minutes after formation of the basal wall.
From their appearance to the escape of the zodspores the time may be from twenty-
five minutes to an hour, but it rarely exceeds forty-five minutes. The emptying of
the sporangium is ordinarily accomplished in from forty-five to one hundred seconds.

The zodspores are. ovateor pyriform, and their protoplasm is hyaline at the
smaller end, while in the rest of the spore it is very granular, and contains two or
three contractile vacuoles (Fig. 8, z, and 9). The zoispores of the species of Sapro-
legnia (Fig. 8, 2) and Pythiopsis (Fig. 68, 2), and of some, probably of all, species
of Achlya (Fig. 9) are provided with two cilia attached to the smaller, hyaline end
of each. The presence of these organs in the first-named genus has been recognized
since they were demonstrated by Thuret (’50), but Cornu was the first (772) to assert

——

WITH NOTES ON OTHER SPECIES. 15

their presence in Achlya. Hartog (87) later corroborated his statement for A.
polyandra and recurva. I have several times recognized cilia on the zodspores of
A, Americana, at the instant of escape, by adding to the water on the slide support-
ing tke specimen a few drops of a one per cent. solution of osmic acid in water, and
then staining 7 situ with a solution of equal parts fuchsin and methyl violet in strong
alcohol. This treatment, recommended by me (’91) in a previous note on the subject,
demonstrates the presence of cilia unmistakably. In an exceptionaily favorable
specimen of A. Americana I have seen the cilia on the living zodspores, both before
and after their escape from the sporangium ; and in A. polyandra one can hardly
fail to notice the very marked ciliary motion within the sporangium during the escape
of the spores. It is not improbable that the zodspores of Aphanomyces are also cili-
ate, but this has not been shown, and the genus needs more careful study than it has
yet received.

Sometimes the spores escape with the ciliate end directed forward, but it appears
to be much more usual for them to pass out in the reverse position. The first spores
to leave do so very rapidly, and are closely crowded together, as though strongly
impelled from behind or attracted from before. In the species of Achlya all the
spores press outward in a close column, but in Saprolegnia there is a gradual
decrease in the rapidity of their escape, and the last spores may linger for some
seconds or even minutes, swimming aimlessly about, and sometimes never finding
the exit.

The zotspores of Saprolegnia, Leptolegnia, Pythiopsis and Leptomitus escape
separately into the water, and swim about freely by means of their forward-pointed cilia.
After a short time, varying from a few seconds to fifteen minutes, each spore ceases
to move about, but continues for a time longer to whirl and rotate, assuming mean-
while a spherical form. Sometimes a few whirls are followed by complete quiet, but
often the spore continues to struggle for ten minutes or more, as if in vigorous pro-
test against giving up its activity.* Finally, it becomes quite spherical and motion-
less, though the cilia may occasionally be seen to wave slowly for a time longer, and
then to disappear by degrees, being apparently withdrawn into the protoplasmic
mass. ‘The spore now becomes encysted by the secretion of a cellulose wall, and so,
for the first time, constitutes a closed cell. Huxley has stated (?82) that the spores

* A curious phenomenon, calculated to arouse speculation as to the nature of the changes of relations and tensions
which take place while the zoéspore is coming to rest, has been observed by me in a spore of an undetermined Sapro-
legnia. After swarming normally, the spore had nearly come to rest, though with prolonged and vigorous struggles,
when suddenly it burst with much force, scattering most of the granular protoplasm to a considerable distance, and

leaving where it had been the nucleus with a small part of the protoplasm. There was, as yet, no trace of a
membrane.

76 THE SAPROLEGNIACEZ OF THE UNITED STATES,

of the Saprolegnia of the salmon disease become motionless and encyst without
swarming on leaving the sporangium.

The zodspores of Achlya, Aphanomyces and Apodachlya only reach the water
just outside of the sporangium, and there become encysted, each one, as it leaves
the mouth, slipping into its place and rounding off at once, so that all the spores from
a sporangium form a hollow sphere or hemisphere, into which the tip of the sporangium
projects slightly (Figs. 10,11). In other words, their cilia serve to carry the spores
only through the mouth of the sporangium. In Achlya the escaping spores form a

column so compact that considerable space is left between it and the wall, and they.
cling closely together during the entire emptying of the sporangium. It is always -

noticeable that the spores in this column keep their long axes parallel with each
other. In Aphanomyces, each of whose sporangia produces but a single file of
zovspores, the spores are compelled by the narrow space in which they are formed to
take a cylindrical shape. They pass in slow succession down to the mouth, and there
become encysted (Fig.11). There is no crowding or clinging together, and the com-
plete emptying of the sporangium requires a much longer time than in the genera
already described.

Hartog attributes this encystment of the spores at the mouth of the sporangium to
a mutual attraction between them which he terms adelphotaxy, and which is also
shown in their pressing closely together during their escape, in Achlya. it may well
be that in Aphanomyces they are prevented by their narrow quarters from showing
the same peculiarity inside of the sporangium. If we accept the existence of such
an attraction, we must believe that it is stronger than the power of the cilia to carry
the spores apart, or else that it is concomitant with a very transient development of
cilia. In the present state of our knowledge some assumption is necessary to account
for the phenomena which have been described. The spores are held together by no
material connections, and, at least in some species, are provided with cilia. That these
phenomena are dependent upon the life of the spore is shown by the fact that, if a
solution of osmic acid, which instantly kills and fixes the spores, be added at the
moment of escape, not only is their accumulation into a sphere stopped, but they are
freely separated and carried about by diffusion currents in the surrounding liquid.
It is hardly necessary to add that osmic acid would so harden any accompanying
mucus from the sporangium that the spores would be held firmly fixed if such sub-
stance were present, as some writers have believed. Hartog’s assumption of a
mutual attraction between the spores seems as little open to objection as any that
can be suggested, and should be so stated as to include a tendency to place their
long axes parallel. This tendency, combined with the effort to secure as much expo-

a a nF

WITH NOTES ON OTHER SPECIES. Fa

sure as possible to the surrounding medium, may account for their arranging them-
selves in a hollow sphere.

We may ask here what causes lead to the emptying of the sporangium. The
existence of a special expulsive substance which swells strongly on absorbing water
was assumed by earlier writers, Strasburger (’80), Biisgen (’82) and DeBary (’84).
It was believed that the supposed “cell plates” of the first separation stage swell
into an intermediate substance enclosing the spores and expelling them by its rapid
and enormous increase in volume when water enters the sporangium. But the exist-
ence of this hypothetical substance has been sufficiently disproved along with that of
the “cell plates.” The only species in which an intermediate substance appears to
exist is one in which it could be of no service in expelling the spores, as will be seen
later; namely, Thraustotheca clavata. Since this species was the one which Biisgen
studied in most detail, the reason for some of his views becomes evident. In general,
there can be little doubt that the spores of the genera now under discussion leave the
sporangia automatically. The preliminary changes in the wall, normally at the
apex of the sporangium, which render the escape of the spores possible, involve inter-
esting physiological questions which will not be discussed at present. But the
nature of the stimulus which causes the spores to avail themselves as quickly as.
possible of the means of escape provided, may be briefly discussed. It frequently
happens in Achlya and Saprolegnia that the spores do not leave a sporangium which
has opened normally, but become encysted within its interior. This failure to leave
the sporangium must evidently be due to the absence of the usual stimulus. Hartog
(87), and before him Cornu (’f7), has held that the presence of free oxygen in the
water is the determining factor. Rothert (’88) disputes this view, as well as Hartog’s
statement that such sporangia appear chiefly in poorly aerated cultures. And Hartog
has more recently (’88) suggested that the spores may vacate the sporangium to find
purer conditions than prevail within it; in other words, to escape from the products
of their own metabolism.

In the first place, it may be remarked that it is much less probable that the
hereditary phenomena of spore development within the sporangium should vary than
that differences should occur in the external conditions of different cultures, or of the
same culture at different times. Since there is no evidence that the formation of the
spores presents any abnormality in those sporangia which fail to discharge their con-
tents, we cannot suppose that the need of purer conditions exists less in one sporan-
gium thanin another. But some sporangia with normally developed mouths fail to
discharge their spores when others are wholly emptied, though it is more common to
find most of the sporangia formed at a given time in the same condition in this

18 THE SAPROLEGNIACE® OF THE UNITED STATES,

respect. This points strongly to some attractive and variable constituent of the sur-
rounding medium as the cause of the normal exit of the spores.* The aimless wan-
dering and frequent failure to escape of the last few spores in a Saprolegnia sporan-
gium may be attributed to the fact that the water from outside has so far filled the
sporangium that the difference between the media within and without the sporangium
has become practically neutralized by their mingling. That the attractive force is
normally very strong is shown by the following observation. A sporangium of
Achlya Americana had developed abnormally three escape papille, one near the apex,
one near the basal wall, and one midway between the others, all on the same side.
The middle mouth was the first to open, and the spores rushed out in normal fashion
until about a third of them had escaped. Then the other two mouths opened almost
simultaneously, and the spores nearest them broke away from the column of which
they formed a part, and crowded out through the new openings. Thus the force
causing their exit was stronger than their tendency to cling together, and drew those
within its range away from the main body. Whether the attraction is due wholly to
the presence of free oxygen seems still open to doubt, although Hartog’s experi-
ments (’88) show it to be a factor of prime importance. It is true that failures of the
sporangia to empty normally occur often in old cultures in which the oxygen may
well be largely exhausted, and very often in cultures which have become overrun by
Bacteria, Infusoria, and other foreign organisms. But cases occur which do not seem
explicable on this basis alone. For example, in cultures on the slide with a compara-
tively small quantity of water, though quite sufficient for the swarming of zodspores,
sporangia often fail to become emptied, yet here there can be no suspicion of any
lack of oxygen, but rather an unusual abundance of it.

In spite of the great differences in the size of the sporangia in different species of
Saprolegniacee, and even in the same species, the size of the zodspores, as measured
after their encystment, varies but little, except in S. an7sospora, which is not yet
known to be American. ‘The encysted spores are quite exactly spherical in all the
American species studied, and are almost always between 8 and 12, in diameter.
Those of a given species may show a tendency toward one or the other of these
extremes, but they present no constant characters in this respect, and are of abso-
lutely no diagnostic value. Each spore contains a single nucleus, one of the original
nuclei of the sporangium, of a nearly globular form, but otherwise like those of the

* On the other hand, the mouths of some Saprolegnia sporangia often resemble very exactly the opening formed
in a glass tube with one closed end, by forcing air into the open end while a small area on the wall is softened in a
flame. The likeness is so striking as to suggest at once the action of an impulsive force from within the sporangium
(see Fig. 50).

a > =

WITH NOTES ON OTHER SPECIES. 79

growing filaments (Fig. 12). The number of spores formed in a sporangium depends,
then, on its size and the thickness of its protoplasmic lining. In an undetermined
species of Saprolegnia I have estimated as nearly as possible the number of
zoospores produced in each of two sporangia of different sizes, with protoplasm of
about average thickness. One 270, long by 26, in average diameter gave rise to
about 120 spores, while from one 873 X 32, about 250 spores escaped. A compari-
son shows that the volumes of these two sporangia bear almost precisely the same
relation to each other as the numbers of zodspores formed in them.

After remaining encysted for a few hours, the zodspore begins to show renewed
activity. -A small, circular perforation is made in the enclosing wall, and the con-
tents begin to emerge in the form of a small papilla, which gradually enlarges until
finally the entire protoplasmic mass lies outside of the cast-off membrane (Fig. 11).
The mass soon takes the form of a biciliate zodspore, and after some preliminary
efforts, darts away and swims freely about. In this second active stage the spore
has exchanged its original form for that of a kidney bean, its cilia being attached at
the lateral depression which corresponds to the hilum of the bean (Fig. 11, 2’). At
the point of attachment the protoplasm is, as in the first form, hyaline. The cilia are
of unequal length, and the shorter is directed forward, the other backward, during
the swarming. It is an interesting fact that this form of the zoospore corresponds
with those of the related Peronosporacew, and with those of some of the Axncylistacew.
It would seem that this must be regarded as the primitive zodspore of the Phycomy-
ceics, as Ward has suggested (’8:3), the form with apical cilia being a secondary one
acquired within the limits of the present family. After half an hour or more of
activity, the spore again settles down and becomes encysted as before.

In most of the genera now under discussion, this double swarming or diplanetism
of the zoospores is the rule, although in exceptional spores the second swarming may
be omitted without apparent influence upon their germinating power (Fig. 11, a). It
would seem that the object of the first swarming is the emptying of the sporangium,
and that of the second the distribution of the spores, to enable them to reach new
sources of food supply; since, as Pfeffer (84) has shown, they are strongly attracted
by various organic substances. Although the first swarming accomplishes both
ends to a considerable degree in Saprolegnia, it does not permit the wide distribution
which the longer second period allows. The zoospores of the second form also seem
to range over a much wider region and to be more actively locomotive than those
of the first. The condition which is exceptional in most of these genera has
become permanent in Pythiopsis, which may represent a reduced Saprolegiia, that,

2A. IPS SiS WAO IE, SOWA LE

80 THE SAPROLEGNIACE® OF THE UNITED STATES,

finding its first swarming period sufficient, has dispensed with the more primitive
second one.

Pringsheim states (60) that the zoospores of Leptomitus lacteus germinate after
a single period of activity. I have seen, however, in pure cultures of this form, abun-
dant empty membranes with every appearance of having been cast off by a diplanetic
zoospore (Fig. 118) ; but unfortunately, I have not observed the actual escape of the
spores from them. H

After its final encystment the spore may germinate at once, if conditions are
favorable; or may remain for a short time capable of germination. In germination
the wall of the encysted spore grows out at one or more points into as many slender
tubes (Fig. 11, a-z), which may reach a Jength equal to several times the diameter
of the spore without nourishment. They soon exhaust the nourishment contained in
the spore, and, if more be not supplied, cease growing and die. If, on the other hand,
food is accessible, growth becomes more rapid and the tubes develop into vigorous
hyphe. At the very beginning of germination, the nearly spherical nucleus of the
spore takes a more elongate form and divides into two (Fig. 13) ; and by the repeated
bipartition of these nuclei and their descendants arise all the nuclei of the hyphe
derived from the spore.

Some observations on the rate of growth of a germ tube of Aphanomyces sp.
may be worth recording here. The tube was produced by a spore which remained
encysted in the head after all the rest had passed into the second swarming stage,
and was growing, therefore, without access to food (Fig. 11, a). At ten a.m. the
tube was just visible as a slight protuberance from the spore (Fig. 11, a); at
eleven it had reached a length of 37, (Fig. 11, g); and at twelve it was 52, long
(Fig. 11,7). The effect of the absence of a supply of food is plainly shown here.
While the growth during the first hour under the stimulus of the reserve materials
contained in the spore amounted to 35,, that of the second hour, when this supply
was becoming exhausted, fell to 15y.

We pass now to a comparison of the genera T'hraustotheca, Dictyuchus and
A planes with those already described. It has been said that the zodspores of Sap-
rolegnia and Achlya sometimes become encysted within the sporangium. This con-
dition is the normal one in the genera above named, but in these the development of a
mouth at the apex is wholly suppressed. In Zhraustotheca the entire wall of the
sporangium, except a narrow basal ring, breaks up after the encystment of the spores
and leaves them free or slightly held together by an intermediate substance. After
a time, they swarm in the laterally biciliate form, encyst again, and germinate. The
sporangial wall of Dictyuchus, on the contrary, does not break down, and the eneysted

WITH NOTES ON OTHER SPECIES. 81

spores press each other so closely that they become irregularly polygonal. Finally
they escape separately through circular perforations of the sporangial wall, just as the
spores of Achlya escape from their cysts, and swarm in the usual second form. The
close compression of the spores within the sporangium leads to a complete fusion of
the encysting wall of each one with those of the others which it touches and with the
sporangial wall. This must be, at least, the morphological explanation of the struc-
ture, although the membrane separating two spores may probably arise as a single
one. After the escape of the spores, as above described, there is left in the sporan-
gium a network of the apparently single walls which separated them (Fig. 112).
Their escape, like that of an Achlya or Saproleynia spore from its cyst, is a slow
operation. The time from the beginning to the completion of the escape of the pro-
toplasm of a single spore may be half an hour or even more, and several hours may
be occupied in the complete emptying of the sporangium. The separate spores follow
no order in their escape, but several in all parts of the sporangium may be escaping
together (Fig. 16).

After its emergence the roughly globular mass contracts and becomes more ellip-
tical, while cilia appear and slowly lengthen. At length, twenty or thirty minutes
after escaping, in case of the undetermined species studied (Fig. 16), only four or six.
minutes after in D. monosporus, according to Leitgeb (’69), the spore darts away.

In Aplanes, according to De Bary (’83), both swarming stages are suppressed,
and the spores, encysted within the sporangium, produce their germ tubes, which
pierce its wall and so reach the water, and perhaps fresh nourishment. But it must
be observed that their loss of the power of locomotion greatly diminishes the prob-
ability of this result. This lessened value of the sporangia as organs of propagation
may explain in some measure the fact that they are rarely developed in this genus.

In Saprolegnia and Achlya those spores which encyst within the sporangium
may escape and swarm in the second form, or they may germinate in situ. It is
evident that the former condition corresponds to a sporangium of Zhraustotheca with
a permanent wall, or to one of Dictyuchus in which the spore cysts have remained
separate, while the latter is just that which is normal for Aplanes. Abnormal
sporangia of genera whose spores are normally diplanetic may therefore be desig-
nated as ‘‘dictyosporangia,” or as “aplanosporangia,” according to the degree of
abnormality shown. Species of Dictyuchus may bear aplanosporangia.

After the emptying of the first sporangium formed from a filament, which may
be termed a primary sporangium, a second one is very commonly developed from the
same hypha, and after it often a tertiary one, and so on for a variable number of gen-
erations. The sporangia of the second and later generations arise by one of three

82 THE SAPROLEGNIACE® OF TINE UNITED STATES,

different modes, in a given species. In Leptomitus, they are formed in basipetal suc-
cession, each segment of the hypha becoming in its turn a sporangium (Figs. 115-
117). In Saprolegnia and Leptolegnia, the new sporangium begins by the upward
growth of the basal wall of the old one, which continues so that the new fills the
cavity of the old more or less completely (Fig. 14). It may even grow out through
the mouth of the latter for some distance. It is not uncommon to see several suc-
cessive sporangia thus “nested” (Fig. 15). Rarely in most species of the genus,
but often in S. monilifera, according to De Bary (’88), the renewal of sporangia by
the third mode, now to be described, occurs. The genera Pythiopsis, Achlya,
Aphanomyces, Thraustotheca, Dictyuchus and Apodachlya are characterized by the
cymose branching of their hyphez in the production of new sporangia. Just below
the basal wall of the primary sporangium arises a lateral branch which, after a period
of growth, develops a secondary sporangium at its tip. Successive repetitions of
this sympodial branching on alternate sides of the apparent axis produce a scor-
pioid cyme, which is usually developed with more or less regularity (Fig.10). In
Pythtopsis there is a more pronounced tendency to the development of a one-sided or
helicoid cyme (Fig. 62). Variations from perfect regularity are, however, the rule
in most forms. It often happens that a branch remains short, and forms a single
sporangium with a part of the axis (Fig. 10, 3). Less often a secondary sporangium
is formed below the primary one, as in Leptomitus. In Aplanes the sporangia are so
sparingly developed that the formation of secondary ones has not been observed.
Hartog has stated (88) that the sporangia of Aphanomyces are renewed as in Sapro-
legnia, but this is certainly not true for A. scaber, in which eymose branching occurs
(Fig. 17); and the same condition probably exists throughout the genus.

The name resting sporangia has been applied to sporangium-like structures
which, after being cut off from their filaments, remain unchanged for a time, but
which may, under suitable conditions, develop and discharge their zodspores in the,
usual way. They are evidently sporangia arrested in their development, probably by
external conditions. Their simplest form is that of the ordinary sporangium, but
frequently they are shorter and broader, and formed in series from the hyphe.

Chlamydospores. Many of the species of Saprolegniacee may produce other
structures beside the sporangia, that are organs of non-sexual propagation and may
be termed chlamydospores, in the sense in which Brefeld uses that term. They
are usually developed in series, as swellings at the ends of the hyphx (Fig. 18), and

WITIL NOTES ON OTHER SPECIES. 83

in their completest development are globular in form (Fig. 19), with dense protoplasm
and slightly thickened walls. The connection between the members of a series
becomes very slight, and they easily fall apart. They may germinate soon after
their formation or after a longer time, but constitute essentially a resting state of
the plant, as compared with sporangia. Their germination consists in the production
of a germ tube or hypha, from which is formed a sporangium with zoospores after a
brief growth. This distinction should be emphasized, that whereas the zoospores
are formed within the “resting sporangia,” the chlamydospores produce them in a
distinct germ tube, although the interior of the chlamydospore is often included in
the cavity of the sporangium (Fig. 20).

Schroeter (69) has described the formation of “ gonidia” in Achlya, but what he
saw appear to have been rather “resting sporangia” than true chlamydospores.
Walz (70) observed and figured the latter in a species of Saprolegnia, and Brefeld
describes (’31) similar structures. They occur also in Aphanomyces according to
Sorokin (76), and Zopf finds bodies of this nature to be constant and characteristic
in Apodachlya pyrifera. But in the last case they are sometimes lateral in position,
are never produced in chains, and appear to be the normal resting form of the plant.
Well-developed organs of this sort have appeared in a culture of Achlya Americana -
(Fig. 18); and in one from a tank for tropical plants under glass they were abundantly
produced by plants with the sporangia of Achlya, on which they completely replaced
the usual sexual organs (Figs. 19, 20).

In comparing the organs of non-sexual reproduction in the Saprolegniacee, we
observe that they do not differ in any essential feature of their origin and formation.
They are, in other words, morphologically similar. But, while the office of the
sporangia is the rapid propagation of the species, the chlamydospores have acquired
the resting habit, and the spore character in the development of a germ hypha. ‘The
“resting sporangia,” in their more specialized forms, constitute an evident link between
normal sporangia and chiamydospores.

When considering the generic relationships within this family, and the best
arrangement for indicating these relationships, one is forced to the conclusion that,
notwithstanding the similarities in structure which have caused Pringsheim (60)
and Hartog (’87) to consider the differences of minor importance, yet the constric-

84 THE SAPROLEGNIACE OF THE UNITED STATES,

tion of the hyphe, the absence of sexual organs in most species, and their peculiar-
ities in the single species in which they are known, with minor variations, of little
weight individually, which distinguish the species of Leptomitus and Apodachlya
from the others of the family, justify their separation as a distinct subfamily. The
discovery of sexual organs in one of these plants, on the other hand, confirms the
indication of the zoospores that they should be included in the present family. Set-
ting them aside, then, as Leptomitee, we may examine the genera constituting the
Saprolegniec.

It is evident that the most primitive condition as regards the zoospores is pre-
sented by the typically diplanetic form, as found in Saproiegnia. But the renewal
of sporangia occurs most commonly, and apparently most typically, by lateral,
cymose branching. Assuming as the primitive form an hypothetical one combining
the two characters above indicated, we must place first in the series Saprolegnia and
Leptolegnia, differing from it only in respect to the second point. Pythiopsis has
economized by suppressing the second swarming stage, and stands alone on this line

of development. In Achlya the first swarming has been reduced to a minimum by —

the mutual attraction of the spores, a newly acquired feature, and Aphanomyces
seems best regarded as a degenerate Achlya rather than as a primitive one. In the
remaining genera the reduction of the first swarming stage, begun in Achlya, is
carried to complete suppression. The condition presented by a dictyosporangium of
Achlya is in the direct line of development from the normal type of that genus, and
that of the aplanosporangium is a further step on the same line. The former condi-
tion becomes modified in two ways—in Thraustotheca, by the early breaking up of
the sporangial wall; and in Dictyuchus, by the coalescence of the encysting walls
and the development of numerous secondary mouths instead of the original primary
one. The latter condition becomes permanent and typical in Aplanes. |

WITH NOTES ON OTHER SPECIES. 85

These ideas concerning the relationships of the genera may be graphically
expressed as follows:
8. Aplanes.

7. Dictyuchus.

6. Thraustotheca.

———

“ Dictyosporangium.”

4. Achlya.

5. Aphanomyces.

3. Pythiopsis.

2. Leptolegnia. |
| |
1. Saprolegnia. |

SEXUAL REPRODUCTION.

The reproductive organs of the second class are morphologically sexual,
though, as will be seen later, they are not physiologically so in all cases. In the fol-
lowing account they will be described as sexual organs without reference to the occur-
rence of a definite sexual act, which will be subsequently discussed. Since they are
the morphological equivalents of the truly sexual organs of related fungi, there is no
occasion to change the names which they received when believed to be also their
functional equivalents.

All of the described species of Saprolegniew produce sexual organs, usually
after the maximum development of sporangia has been passed ; indeed it is impos-
sible to distinguish the species except by their sexual organs. None of the Lepto-

86 THE SAPROLEGNIACE OF THE UNITED STATES,

mitece has been known heretofore to bear them, and their peculiarities in the single
form in which these have been seen will be discussed in connection with the deserip-
tion of that species (Apod. completa). The special office of these organs is the pro-
duction of bodies which, like the chlamydospores above described, may in some cases
germinate at once, but ordinarily constitute a resting condition of the fungus. The
conditions most favorable to the development of the sexual organs are not yet fully
understood, and the readiness with which they are produced varies much with the.
species. The species of Saprolegnia, for instance, produce their sexual organs less
freely and less certainly in cultures than do those of Achlya.

The sexual organs are produced, like the sporangia, from the main hyphe or
from branches, and are commonly terminal, though sometimes intercalary, in position.
The female organ, the oogonium, develops as a swelling of the thread which bears it,
which may be termed, when not a primary filament, the oogonial branch. The swell-
ing increases as the protoplasm accumulates, until its definite form is reached. If
the o6gonium be terminal, its form is most commonly globular (Figs. 52, 71), though
often with a cylindrical basal-portion (Fig. 43), and sometimes ellipsoidal (Figs. 87,
99). When the extreme tip of the hypha is not involved in the swelling, it forms an
apiculus to the odgonium (Figs. 27,57). Intercalary odgonia are oftenest barrel-
shaped (Fig. 59). After the form and size of the odgonium has been determined, it
is separated from its hypha by a transverse wall, or, if it be intercalary, by two such
walls. The formation of the walls is characterized by the same phenomena which
are observed when the basal wall of the sporangium is formed. The wall of the
odgonium has meanwhile been thickening by the deposit of new material upon its
inner surface. In the simplest cases this deposit takes place evenly, producing a
smooth wall of equal thickness throughout (Fig. 81). A somewhat less even deposit
produces a roughened inner surface (Fig. 77) ; or the thickening may be wholly lack-
ing on certain definite areas more or Jess numerously scattered over the wall of the
oogonium, causing the pitting of the membrane which is a constant and characteristic
feature of certain species (Figs. 43, 72). Instead of presenting a smooth outer sur-
face, the whole membrane may be, from a very early stage, raised at intervals into
outgrowths of varying height and frequency, giving it a warty or spiny appearance
(Figs. 55, 104).

While the membranes of the vegetative filaments and of the sporangia always
give the characteristic cellulose reaction with chloroiodide of zinc, those of the fully
developed odgonia take with this reagent * a beautiful Indian-red shade, showing that

*This was prepared by dissolving Griibler’s solid chloroiodide of zine in its own weight of water, or somewhat

less, and then adding metallic iodine until the dcsired sherry-brown color was obtained.

WITH NOTES ON OTHER SPECIES. 87

some chemical change has taken place. Since the pits are marked by colorless areas
in the otherwise deeply colored wall, the original membrane must have become so
changed, at those points at least, that it remains uncolored by the reagent. It seems
probable that the whole outer membrane assumes this character, and that the color is
produced entirely in the secondary deposit.

The male organs, or antheridia, are, when present, almost always borne on slen-
der lateral antheridial branches. In some species they ave very rarely or never devel-
oped (Figs. 43,104). Where they are present, they are not necessarily found in
connection with all the odgonia (Figs. 40, 75, 76), though they may be invariably so
(Figs. 52, 71, 105). The number of antheridia attached to a single o6gonium shows
very little tendency to definiteness, except in A. racemosa (Fig. 94). The most that
can be said is that in a given species there is a general tendency to an abundant pro-
duction of antheridia, or the reverse.

The antheridial branches arise from the main filaments or from odgonial branches,
sometimes exclusively from one or the other, in other species from both. They may
be very short and simple (Fig. 98), or long and much branched (Figs. 51, 71).
From their tips antheridia are cut off by transverse walls, and rarely are intercalary
also. The antheridia are cylindrical or clavate in form, somewhat thicker than
the branches, and with slightly denser protoplasm. Their form is very constant for a
given species and, in connection with their position and origin, affords important
characters for specific diagnoses. Their walls show in a less marked degree the
reaction of the odgonial walls.

The same primary filament may give rise to both odgonial and antheridial
branches, or it may produce only those of one sort. Since it is practically impossible
to determine in ordinary cultures whether two filaments belong to the same plant,
and since definite cultures from a single zodspore have not been made, we cannot say
whether species whose hyphe are unisexual are truly dicecious or not. It is safe,
however, to apply to them the term used by DeBary, diclinous (Figs. 51, 88). The
same author calls species with bisexual filaments androgynous. Among species of
the latter kind, which constitute the large majority of the Saprolegniew, the anthe-
ridia may attach themselves to oogonia from the same or from other filaments. Most
of them reach odgonia from the same hypha, probably because these are nearer.

In one species not yet met with in America, S. hypogyna, a single branch is

bisexual, the antheridium being formed from a cell cut off by a second wall immedi-

ately below the oogonium. This is the only known case in this family of antheridia
without antheridial branches.

PNG TRS SS WO SOAS 1h

88 THE SAPROLEGNIACE# OF THE UNITED STATES,

In case of the androgynous species, the antheridial branches begin to appear soon
after the odgonial ones (Fig. 21); but the antheridia have usually been formed and
come into contact with the cégonium before the basal wall of the latter has appeared.
Commonly they are applied by their sides to the odgonial wall, but in a few species
(Figs. 54, 94) they present their ends, so that their longer axes are nearly at right
angles with the wall, instead of parallel with it, as in most species.

When a certain stage in the differentiation of the contents of the odgonium has
been reached, as will be described later, the antheridia give rise, in most cases, to
slender tubular outgrowths from the sides applied to the odgonial wall. The tubes pene-
trate this wall and grow into the cavity within, remaining simple or branching. These
structures are, morphologically at least, fertilization tubes. In species with pitted
odgonia the antheridia are often, but not always, applied to the thin places, and the fer-
tilization tubes can thus penetrate more easily. But the old view that the pits are
perforations of the membrane for the admission of these tubes is untenable from any
point of view.

The sexual organs are, then, specialized branches; but their special character
does not prevent their showing occasional reversional features, recalling their primi-
tive nature. The odgonial branch may subdivide and bear an odgonium on each di-
vision (Fig. 22). It is not uncommon to see a young odgonium which has ceased its
normal development and produced one or more smaller odgonia by proliferation from
its surface (Fig. 23); and I have seen in A. Americana a fully formed odgonium,
which, after the formation of its basal wall, had reverted to the vegetative condition,
so to speak, and had given rise to an odgonial and an antheridial branch which had
reached their full normal development (Fig. 24). The production of an antheridial
branch from the very body of an odgonium occurs so commonly as to be normal in
A, racemosa (Fig. 96), in which the branch arises as often above the basal wall of the
oogonium as below it; but the antheridium is probably cut off from its branch before
the odgonium is cut off. Further proof that there is no fundamental difference
between the two kinds of sexual branches may be found in the fact that antheridial
branches may produce at their ends small, though abortive, ojgonium-like swellings,
even after giving off branchlets with normal antheridia (Fig. 25). I believe I have
also seen the formation of a spore-like body in a similar swelling, as observed by Zopf
(90) in Peronospora calotheca, but have not been able to feel certain on this point.

Having now traced the origin of the sexual branches and the formation of the
sexual organs in general, we pass to the detailed examination of the fate of their pro-
toplasmic contents. The dense mass of protoplasm which fills the ojgonium when it
has attained its final form, contains, like that of the sporangium, very numerous

WITH NOTES ON OTHER SPECIES. 89

nuclei irregularly scattered through it. The protoplasm is at first pretty evenly dis-
tributed through the cavity of the odgonium, and encloses irregular vacuoles. But it
soon forms a definite parietal layer which is densest next the wall, and the vacuoles
fuse into a single large central one. The nuclei are still indefinitely arranged (Fig. 30).
They vary considerably in size, and in structure are identical with those of the vege-
tative filaments from which they are derived. After the growth of the odgonium has
ceased and the protoplasm has become parietal in position, the outer walls thicken
and the basal wall is formed, as already described.

After an interval the parietal protoplasm begins to undergo changes preliminary
to becoming collected into one or more globular masses. We owe our first exact
knowledge of these phenomena to DeBary (’81), who studied them in several species.
The figures here given of the later stages of the process in a species not studied by
him, A. apiculata, may serve at least to corroborate and supplement his account and
illustrations (Figs. 26,27). The first change observed consists in the appearance in
the protoplasm of numerous light spots, approximately circular in surface view, which
may be seen to slowly shift their positions and eventually to disappear. ‘These spots
were thought by Pringsheim (’58) to mark the positions of future pits in the wall,
which he regarded as perforations formed by resorption. Reinke (’69), Cornu (’72), -
and DeBary (81), showed that the spots are much more numerous than the pits and
that they occur in all species without regard to the structure of the wall. It is
undoubtedly true that they are much more numerous than the pits in pitted oogonia
and that they bear no relation to them. DeBary’s explanation (81) of their nature
is supported by their appearance in section (Fig. 32). They are doubtless the expres-
sion of vacuoles in the parietal protoplasmic layer, formed by accumulations of cell-
sap, and finally empty into the central vacuole. Thus the central cavity becomes
gradually larger and the wall-layer correspondingly thinner and denser (Fig. 33).
The upper vacuole in Fig. 32 has united with the central one in Fig. 33. After the
vacuoles have disappeared, the proper degree of density having been reached, as we may
suppose, the protoplasm begins to flow towards certain regions and away from others,
causing a heaping up at the former and a thinning at the latter places. These accu-
mulations increase at the expense of the surrounding material until there are formed
a number of pretty distinct masses connected by a thin parietal sheet of protoplasm,
which is still a continuous lining of the wall (Fig. 26,a@). This layer now breaks and
its rupture is followed by a large increase in the volume of the protoplasmic masses,
corresponding to the stage of swelling in the sporangium. At the same time, the
basal wall, previously convex downward, becomes reversed in position, indicating a
loss of turgescence, as in the sporangium ; and the fragments of the parictal lining

90 THE SAPROLEGNIACEH OF THE UNITED STATES,

are absorbed into the masses, which we may call, following the homology of the spo-
rangium, odsphere-origins (Fig. 26, 6). If the rapidly shifting vacuoles present in
the sporangium at this stage are also formed here, the protoplasm is too dense to per-
mit their recognition. The odsphere origins, which, when numerous, may nearly fill
the ojgonium at their period of greatest swelling, now contract rather rapidly, ap-
proaching more and more nearly to the spherical form. During this process there are
separated from the origins small masses of protoplasm which may moveaway a short
distance and may remain detached for some minutes (Fig. 26, c) ; but they appear to
be always taken up again by the same origins from which they were separated (Fig.
26, d). The rounding off is soon completed, and the odgonium contains a number of
fully formed odspheres. All the odgonia of some species, and the smallest of most
others, produce only a single odsphere in each. The formation of these follows the same
course as that above described for the polysporic oogonium, with certain necessary
simplifications. As has been intimated, the odspheres are normally spherical, but they
may assume an ellipsoidal or cylindrical form when compelled to do so by the size
and shape of the space within which they are developed.

The separation of protoplasmic fragments from the zodspores and odspheres during
their final contraction and rounding off, and their subsequent reabsorption by their
parent masses, constitute phenomena of peculiar interest. They were first observed by
DeBary (’81) in connection with the odspheres, where they are the more conspicuous ;
and their formation has been regarded as analogous with that of the polar bodies of
the animal egg, while their reabsorption has been explained as compensating for the
absence of an act of fertilization. But the fact that the nuclei of the odspheres are
reduced to one or a very few at the time of their formation makes it certain that these
fragments are non-nucleate and therefore not analogous to polar bodies; while the
fact of their separation from the zoospores also removes the possibility of their sexual
significance. They probably represent in their formation the persistence of some
inherited phenomenon of no present functional significance, as Hartog (’92) has sug-
gested.

It will be seen that, omitting the preliminary formation of vacuoles, the changes
which characterize the formation of the odspheres are identical with those observed
in the development of the zoospores. But the time required for the former is much
longer, for the zojspores may escape an hour after the cutting off of the sporangium,
while the odspheres may require eight hours or more for their formation.

As soon as the odspheres are differentiated, the antheridia, when present, begin to
produce the fertilization tubes, which soon reach and come into more or less close
contact with the former. The tendency of the tubes to grow towards the odspheres

WITH NOTES ON OTHER SPECIES. 91

and to attach themselves to them is clearly marked, but does not appear to be so
strong and invariably active as it has been said to be by most writers.

Hach odsphere now secretes about itself a delicate cellulose wall, which gradually
increases by successive deposits until it attains a considerable thickness. From the
time of the appearance of the wall these bodies are no longer oéspheres, but odspores.
The fertilization tubes soon begin to fade and finally quite disappear, as do also the
antheridia and even the antheridial branches, in some species.

By the earlier writers it was assumed from the fact of their presence and from
the analogy of related fungi, that the tubes are functional organs of impregnation
and that an actual fertilization occurs. Some, especially Pringsheim (’55, 58, ’60),
argued for the necessity of fertilization. This author at one time (’60) regarded cer-
tain peculiar filaments, whose peculiarity was really due to Chytridiaceous parasites,
as male filaments of species which have no antheridial branches; but later (’74), he
gave up this view and considered plants of the latter sort as parthenogenetic forms of
sexual species. Reinke (’69) described uniciliate spermatozoid-like bodies as the fer-
tiizing element in S. monoica. These were probably zodspores of Chytridiacee. Cornu
(72) assumed and argued for the necessity of fertilization, and maintained the ina-
bility of unfertilized odspheres to form ripe odspores. Doubt of the existence of
functional sexuality in these fungi was first expressed by DeBary (81) and was based
on his failure to observe any passage of material from tube to odsphere, or even any
opening in the tube. Pringsheim (82) opposed these views very strongly with argu-
ments and with an account of observations of the penetration of the odspheres by
amoeboid swarmers—“ spermamcebe ”—developed in the fertilization tubes and set
free from them. Zopf (’82) described ameeboid parasites of Saproleyniacee and
attributed Pringsheim’s spermamcebe to this source. Ward’s observations (783),
while not extensive, confirmed DeBary’s. The further discussion of the subject con-
sisted simply in the maintenance of their former positions by those engaged, and may
be followed in subsequent papers of DeBary (’83), Pringsheim (’83, ’83a), Miller
(83), and Zopf (83). The result has been that the conclusions of DeBary have gen-
erally been adopted and made the basis of discussions of the group. The writer has
attempted to investigate the question independently in connection with the cytol-
ogy of the sexual organs, to which we may now turn.

The structure and nuclear changes of these organs have been studied chiefly in
the genera Saprolegnia and Aphanomyces by previous writers, and by the present
one chiefly in Achlya Americana and A. apiculata. The method employed in these
investigations has been that of serial sections. Flies well covered with hyphe of the
species to be studied, bearing abundant sexual organs in various stages of develop-

92 THE SAPROLEGNIACEH OF TUE UNITED STATES,

ment, were fixed with a saturated aqueons solution of picric acid for twenty-four
hours, in the earlier part of the work. Later, this treatment was replaced by expo-
sure for fifteen or twenty minutes to a hot saturated aqueous solution of corrosive
sublimate (HgCl,). This reagent fixes the cell contents without even the slight dis-
tortion caused by picric acid, and is strongly to be recommended for such work, as
has been done by Hartog (89a). The whole specimen was, after fixation, washed
and soaked in fifty per cent. aleohol, and then stained for twenty-four hours in
Grenacher’s or Kleinenberg’s hematoxylin. After being washed again and passed
through graded alcohols and chloroform into paraffin, in the usual manner, the fly
with attached fungi was imbedded in paraffin and cut into sections about 7 in thick-
ness by means of the Minot microtome. The sections were then mounted serially in
balsam.

The very numerous nuclei carried into the young odgonium with the protoplasm
exhibit the structure of the mycelial nuclei, as has been said (Fig. 30). The num-
ber of these nuclei bears no relation to the number of odspheres to be formed, except
as both are controlled by the amount of protoplasm in the odgonium. In nine sec-
tions, including the whole of a young odgonium, about 60. in diameter, of A. apzcu-
lata, I have counted 175 nuclear structures. With liberal allowance for the presence
of parts of the same nucleus in two sections, it is not probable that the odgonium
contained Jess than 100 nuclei; yet this species rarely produces more than five
odspheres in an odgonium. The nuclei remain passive during the formation of the
central vacuole, and finally lie distributed through the parietal layer (Fig. 30). I
have never been able to see any evidence of division in odgonia! nuclei, and believe,
with Hartog (’92) and Dangeard (’90), that it does not occur. After the formation
of the parietal layer, the nuclei appear to migrate towards each other and to fuse in
pairs (Fig. 31); and a little later they are seen to be much less numerous and larger,
as well as far less deeply stained by hematoxylin (Fig. 32, 33). Indeed, a careful
search with well-managed illumination is necessary for their detection. This is due
to the fact that their chromatin masses largely lose their characteristic power and are
masked by the granular protoplasm, while the nuclear membrane becomes barely
recognizable. The space between the membrane and the chromosome, occupied by
the hyaline part of the nucleus, is proportionally larger than in the vegetative nuclei ;
and it is probably this fact, combined with the faintness of the other parts, that has
led Hartog (?39) to attribute to these fusion-nuclei the vacuolated appearance of the
young odjgonium. That the two conditions are quite distinct, though occurring
simultaneously, as Dangeard (’90) has maintained, may be seen in Fig. 32. The
observed reduction in the number of the nuclei is plainly due to nuclear fusions (Fig.

WITH NOTES ON OTHER SPECIES. 93

31), probably many times repeated, but whether all the original nuclei are involved
in these fusions, or whether some of them degenerate and disappear like those of the
periplasm of Peronospora, as described by Wager (89), is uncertain. When the
protoplasmic layer reaches its greatest density and regularity of arrangement, the
nuclei are in this indistinct condition (Fig. 33). Just when and how they regain
the vegetative structure, I am not yet able to say, having unfortunately failed to
obtain sections of odgonia at the stage of the formation of the odsphere origins and
of the rounding off of the odspheres. It is certain, however, that, as Hartog has said
(89), and contrary to the statements of Dangeard (’90), the young odspores contain
but a single rather large nucleus (Fig. 35). This is commonly true also of the fully
formed odspheres, but sometimes these contain two nuclei which have not yet fused,
though usually lying near together (Fig. 36). Hartog (’92) states that in Saproleg-
nia the reduction of the number of nuclei to that of the future odspheres is completed
as early as the beginning of the formation of the origins, while in Achlya it may be
delayed until the young odspore. My observations agree with these so far as A.
Americana is concerned, but I have not examined any species of Saprolegnia. The
single nucleus, or the two which are to form it, shows the structure and reactions of
the vegetative nuclei.

Although its protoplasm is little denser than that of the vegetative threads, the
antheridium is plurinucleate (Fig. 34, a). When the fertilization tube is formed,
most of the protoplasm and usually all of the nuclei of the antheridium pass into it
(Fig. 34, a). Hartog states (92) that the nuclei of the tubes are derived by divi-
sion from those of the antheridia ; but, so far as A. Amerzcana is concerned, I have
seen no reason for supposing that nuclear divisions occur here more than in the other
reproductive organs. The number of nuclei in different antheridia of this species
does not vary widely, and the number in a tube corresponds pretty closely, as a rule,
to the number in an antheridium (Fig. 34, a); and as the growth of the fertilization
tube is accomplished apparently by the migration of the protoplasmic contents of the
antheridium, and not by any increase in its amount, there is no @ priorz reason for
nuclear division, under the circumstances. After passing into the tubes, the nuclei
undergo no change. It is occasionally possible to find a fortunate section through
the sexual organs and odspores, like that figured in Fig. 34, a, which shows well their
relations and the fate of the tubes. And one always finds that, in whatever stage of
development the odspores may be, the tubes are completely closed, as was stated by
DeBary (’81), and show their walls sharply defined throughout ; and that their pro-
toplasm and nuclei are in essentially the same condition until they begin to degener-
ate after the complete ripening of the spores. One sometimes observes a nucleus in

94 THE SAPROLEGNIACEA OF THE UNITED STATES,

the very end of the tube after the wall of the ojspore has become thick and dense
(Fig. 34, a). Since it is impossible to accept any view of fertilization which does
not involve the passage of a nucleus from the tube, these facts must remove all pos-
sible doubt of the correctness of the belief expressed by DeBary that these fungi are
no longer truly sexual, in spite of their fully developed sexual organs.

After the thickening of its wall, a period of a few days is necessary for the com-
plete ripening of the odspore. The visible sign of this process lies in the separation
of the fatty material, which has been until now scattered in small globules through
the protoplasm, into one or a few large and more or less spherical masses. While in
certain species it characteristically remains in several portions (Fig. 68), it is com-
monly fused into a single drop (Fig. 111). This generally continues surrounded by
protoplasm and nearly central (Figs. 95, 111), although it may be so much displaced
as to leave only a thin film of protoplasm over one side. Odspores of this type are
called centric, to distinguish them from those of excentric structure, in which the oil
globule or globules and the protoplasmic mass occupy opposite sides of the spore,
and are in contact only by their margins (Figs. 68, 73).

After a period of rest which varies greatly in different species, the ojspores may
germinate. Preparation for this process consists in the breaking up of the oil glob-
ule and its rediffusion through the protoplasm. The inner membrane of the spore
now grows out through a rupture in the outer one into a short thread similar in
structure to a vegetative hypha (Fig. 29, a). If this thread comes at once into con-
tact with available nourishment, it may develop rhizoids and branch, and so grow
directly into a new plant. But if nourishment be not immediately at hand, the hypha,
after a brief growth, forms a sporangium at its apex in the manner typical of its
genus. There can be no doubt that the numerous nuclei of the germ-hypha arise
from the division of the single nucleus of the odspore, but how early the division
begins is not certain. Dangeard (’90) maintains that the odspores are always multi-
nucleate, and it may be that this division begins, at least in some species, quite early,
and that therefore he has overlooked the uninucleate stage. He suggests that a dif
ference may be found between odspores which germinate at once and those which
require a considerable period of rest. But there is no doubt that the odspores of A.
apiculata, which, according to DeBary (’84), germinate as soon as they are ripe, are

distinctly uninucleate.

In comparing the chlamydospores and the odgonia of the Saprolegniacee, we may
assume what is probably true, that no nuclear changes occur within the former. If

WITH NOTES ON OTHER SPECIES. 95

so, then the only real differences between these two organs are found in the concen-
tration of the protoplasmic contents of the latter into one or several separate masses
and the fusion of the nuclei of these masses into one, to be restored by subsequent
division. These differences are of purely physiological and sexual significance and
are inheritances from the truly sexual ancestors of these plants. But on the other
hand, it is evident that sporangia, chlamydospores, and o5gonia are strictly homolo-
gous organs.

It is easy to speculate upon the relationships of the present family to various
other groups of Algw and Phycomycetes ; but this would be of little profit. Until
our knowledge of some details of the development of the plants concerned, especially
of their cytology, is more complete, it seems well to refrain from further conjecture.

OcCURRENCE AND DISTRIBUTION.

The Saprolegmacee are found more or less commonly in all fresh waters, but
prefer such as are pure and clear. They occur most abundantly and develop most
Juxuriantly in such waters as contain and favor the growth of the pure-water Algze,
Conjugate and Chlorophycee. In stagnant waters or those which are polluted by
organic matter, they may be found, but their development is usually slow and -
feeble, and is often quite arrested by the swarms of Bacteria and Infusoria which find
their congenial conditions in such places. The most striking exception to this
general statement is afforded by Zeptomitus lacteus, which grows especially in
waters containing considerable organic impurity ; and the same is perhaps true of the
other Leptomitec.

These plants are usually saprophytic and grow upon animal and vegetable
remains. ‘The latter may include dead, woody or herbaceous parts of vascular plants
or even decaying Algz. On the last I have found ZL. lacteus growing vigorously.
But it is on animal remains that they flourish best; and of these the most favorable
appear to be insect bodies. The reason for this fact probably lies in the circumstance
that these bodies, being protected by a chitinous skeleton, are not so exposed to the
attacks of putrefactive Bacteria, and therefore decompose slowly and cause little
pollution of the surrounding water, as compared with a bit of naked flesh of the same
bulk. The Saprolegniaceew, too, undoubtedly act as scavengers in appropriating for
their own growth the more readily available organic compounds of the dead body.
In cultures in a small volume of water, the evidences of decay disappear after a few
days, coincidently with, or even before the cessation of active growth in the fungus,
consequent upon the exhaustion of available nourishment.

A. P. 8.—VOL. XVII. M.

96 THE SAPROLEGNIACEH OF THE UNITED STATES,

One or more species of the group are facultative parasites which can attack liv-
ing fishes and Amphibia, and cause serious disease which usually results in death.
Under certain conditions which are not yet well determined, the disease may become
epizoétic and cause great mortality in a lake or stream or in some restricted part of
it. Notices of such cases occur throughout the literature from the time of Hannover
(739) and Unger (’43) to the present. The most famous outbreak, and the one best
studied, was that on salmon and some related fishes in the rivers Esk, Eden, Nith,
and others in England and Scotland. The details concerning this attack and con-
cerning the pathology of the disease may be found in the papers of Smith (’78), Stir-
ling (78, 79, °79 a), Brook (79), Buckland (’80), and Huxley (’82). It is sufficient
to say here that Huxley was convinced that the disease was caused by a truly para-
sitic Saprelegnia, called by all writers on the disease, S. ferax. The only reference to
the occurrence of a similar epizodtic in America which has come to my notice, is a
brief note by Gerard (’78), who reported severe mortality among fishes, from this
cause, in the Passaic river in New Jersey.

Murray (’85) and Schnetzler (57) have found that the zodspores of “ S. ferax”
cultivated on flies can attack living fishes and frog-tadpoles and produce a growth of
the fungus which kills the victim. Some facts concerning the effects of A. racemosa
in a fish-hatchery will be discussed in connection with the description of that species.

Owing to the absence of suitable substrata for their development in mass, and
the brief time required for the completion of their life-cycle, these plants are not often
found growing spontaneously; and this fact has led to the belief that they are some-
what rare or difficult to obtain. But the writer’s experience in the United States
fully agrees with that of DeBary in Europe that this is by no means the case. The
Jast-named author has given (’88) very practical hints for obtaining and cultivating
them which it will not be superfluous to repeat here, with some additions drawn from
personal experience. For reasons above stated, the most prolific source of supply is
water containing green Algz, and the best substratum is afforded by insects such as
common house-flies or meal-worms. For material, a handful of Algz may be taken
from the stream, pond, or pool in which they are growing and placed in a collecting
bottle or other vessel which will protect them from drying. In the laboratory, these
are placed in a vessel of water from the public or private water supply, and the cul-
ture insects are thrown upon its surface. The collection of a mass of Algz without
water, except that retained by the mass, reduces the bulk of specimens, which is of
importance when they are taken at a distance from the laboratory, and largely excludes
aquatic organisms which might make trouble in the cultures; while experience shows

WITIL NOTES ON OTHER SPECIES. 97

that the zoospores and odspores of the Saprolegniacew are carried with the Algz to
a large extent. If it is desirable to avoid any possible infection from other sources
than the mass of Algze concerned, the water may be filtered, heated to boiling, and
then cooled, before the specimen is placed in it. DeBary found that, in practice, the
water supply of Strassburg never produced any of these fungi in cultures made with
water from its pipes alone; and I have had the same experience in repeated trials
with that of Amherst. But water from the Cambridge pipes, and doubtless that from
others, will yield them at certain seasons, at least. The insects used may be freshly
killed, and their chitinous covering should be broken as little as possible ; but I have
found that, for winter cultures when fresh insects are not. readily available, an excel-
lent substitute may be found in dead house-flies, collected in the fall and kept dry
and exposed to the air, but protected from dust. Since the dry surfaces of insects
are not readily wetted by water, it has proved useful to moisten them, whether fresh
or dried, with alcohol, and then to soak them in water for a few minutes to remove the
alcoho]. They will then, when thrown into the culture vessel, sink until their bodies
are mostly below the surface and so present a much larger area to the swimming
zoospores of Saprolegniacew than if dry and floating largely above the surface.

Since the zodspores depend for their activity on a sufficient supply of oxygen
we may expect them to be most abundant near the surface of the water, and since
they are chemotactic, being strongly attracted by nutrient substances, they must
readily reach the floating insects and germinate upon their bodies. An average time
for the appearance of the young hyphe is perhaps two days from the beginning of
the culture, but one day is ample time, as a rule, for the zodspores to have effected an
attachment to the substratum. The insects should now be transferred to a vessel of
fresh, clean water, and here the development of the fungus may be followed. The
water should be carefully changed daily or less often, as may be required, until the
maximum of vegetative activity is past. For superficial examination, the whole insect
with attached fungi may be floated upona slide. For more thorough study, parts seen
by this preliminary method to be in the desired condition may be cut off and mounted
under a cover, or used for a hanging drop culture. Rothert (’88) has pointed out that
well-grown filaments with reproductive organs continue to develop normally after
being cut off, until their protoplasm is exhausted.

It is not easy, although it is usually possible, to obtain from a mixed culture of
several species, pure cultures of each. This may be accomplished by using sterilized
water, fresh, clean insects, well-soaked in alcohol and distilled water, and a very small
quantity of the fungus, preferably zodspores from a single sporangium. <A few
attempts will give the desired result, if the first does not. The use of small portions

98 THE SAPROLEGNIACEH OF THE UNITED STATES,

of successive cultures is very useful here, as in the culture of Bacteria, in eliminating
all but a given form. Many species grow well on a flooded slide in the saturated
atmosphere of a moist chamber. Cultures may be pretty safely sent by mail in suitable
mailing tubes for liquids, but should be sent at the proper stage of development.
After some experience in this matter, it appears to the writer that the best time for
mailing a specimen which will be more than a day en route is when the sexual organs
are just fully formed. They should be placed in a tube filled with clean, preferably
sterilized, water and mailed at once. If sent later, the plants are likely to fall in
pieces on the way ; while, if sent earlier, the close confinement for some time and the
consequent vitiation of the water seem to reduce their vigor so that they subsequently
fail to produce sexual organs.

The application of the above described culture methods to American materials
has shown, as has keen said, that these plants are not less abundant with us than in
Europe. Among the many samples of material from the most varied sources, which
he investigated, only one failed to furnish to DeBary some member of this family.
In a Jarge number of cultures from fresh waters of all kinds, rivers, ponds, brooks,
spring-holes, drains, and rain-pools of brief duration, in short, from wherever Algz
appear, I have failed only two or three times to obtain Saprolegniacee. A single
culture may often yield several species. DeBary gives seven as the largest number
obtained by him from any one source. I have obtained nine species from two hand-
fuls of moss and Algze from a small shallow pool just at the border between a swamp
and damp pine woods. On dead branches in this pool grew Mougeotia sp. and
Ulothricacece, and over the mosses bordering it crept the filaments of a species of
Tolypothrix. Cultures produced at once S. diclina and torulosa, A. Americana,
apiculata, racemosa, var. stelligera, and papillosa, Dictyuchus sp., and L. lacteus.
After the material had stood in an open jar near a north window for a few months,
the green Algze had disappeared, but the mosses and TYolypothric had grown freely.
Flies dropped into the jar soon bore Aph. levis in abundance.

it is not yet possible to generalize at all concerning the distribution of the
species of this family ; but it seems probable that a great majority of them are likely
to prove cosmopolitan. One difference has been very conspicuous, however, in the
cultures I have studied ; namely, that in those from the Northern States there has
been a distinct predominance of species of Achlya, while in those from the Southern
States specimens of Saprolegnia, if not different species, have been far more abun-
dant.

The following synopsis of American species can, of course, be only a fragmen-
tary representation of our flora, since it covers but few localities and these only in a

WITH NOTES ON OTHER SPECIES. 99

desultory way. But the fact that of the thirty-four established European species,
sixteen are here included, while five species previously unknown are described, shows
what we may expect as the result of thorough exploration of many localities. It is
hoped that the present contribution may serve to stimulate such exploration.

HISTORICAL.

The first references to any of the Saprolegniacee appear to have been those of
Ledermiiller in 1760, of Wrisberg in 1765, and of Spallanzani in 1777. By these and
later writers for a long time they were regarded as Algze and were described by most
under the generic name Conferva, which included, in its Linnzan application, the fila-
mentous aquatic plants, generally. The earliest binomials appear to be those of the
Flora Danica (1780), Byssus aquatica, and of Schrank (1789), Conferva piscium. Pre-
vious writers had seen these fungi on flies in water, but in Schrank’s name is the first
record of their occurrence on fishes. The earliest figures are those of the Flora
Danica (1780), of Dillwyn (09), and of Lyngbye (719). As the early observers saw
and figured only the sporangia, it is impossible to refer their plants to the proper
species. It can only be said that the names Byssus aquatica Fl. Dan. and Vaucheria
aquatica Lyngb. refer to species of Achlya. Dillwyn figured the Conferva lactea of
Roth (1789), which is recognizable as our Leptomitus lacteus Ag. Gruithuisen de-
scribed (21) a fungus on the remains of a dead snail, and for the first time figured
the escaping zodspores of Saprolegnia, though without cilia. This form he called
Conferva ferax, a name which was subsequently used promiscuously by many
authors for any of the larger species of this family. It was first applied to a distinctly
characterized form by Thuret (’50), though without an understanding of the real
specific differences among these plants. Carus next (23) described a fungus on
salamander larvee, with spores collecting in a globe at the mouth of the sporangium,
which he called Hydronema. We observed several characteristic features in the
development of the form, and recognized its points of difference from Gruithuisen’s
fungus. In an appendix to Carus’ paper, Nees von Hsenbeck (’23) established the
genera Saprolegnia and Achlya on the distinctive differences in the escape of the
zodspores which we recognize as their most salient characters, to-day. He called
Gruithuisen’s fungus S. molluscorum, and Carus’ form A. prolifera; but he appar-
ently did not know the sexual organs, and it is impossible to identify the species
intended by him. A year later, Agardh (24) included in his genus Leptomitus all
described Saprolegniacee under the names J. clavatus, prolifer, and ferax, grouping
the forms of earlier writers rather according to substrata than by structure, and mix-

100 THE SAPROLEGNIACEZ OF THE UNITED STATES,

ing his synonymy confusedly. Berkeley (’33) followed Agardh’s generic arrange-
ment, and called the form he figured Leptomztus piscidicola.

After brief and unimportant mention of these plants in earlier papers, Meyen
described (’39) some features of the development and escape of the spores and of
their germination. He also observed dictyosporangia. Now followed a series of
accounts of observations concerning the attacks of Saprolegniacex on aquatic Verte-
brates by Hannover (’39 and 742), Stilling (41), Bennett (’41), and Goodsir (42).
These papers contained little of real importance except Hannover’s second one, which
has been before mentioned as containing the first good account of the development
and later history of the zodspores. Unger’s account (’43) was in some respects less
complete than that of Hannover. All the writers yet mentioned dealt only with the
sporangia, in most cases of the Saprolegnia type; but nearly all called their plants
Achlya prolifera. In Schleiden’s “ Grundziige” (45), we find the first account of a
second and larger sort of spores, which we now know as the odspores. These were
again mentioned by Naegeli (47) and by Braun (51), the latter of whom also
described the antheridial branches. Naegeli (’47) speaks of a third sort of reproduc-
tive organs, which were probably, like those described by Cienkowski (755) the
sporangia of parasitic Chytridiacee of the genus Olpidiopsis. The general features
of the development of both sporangia and odgonia were described at this time by
Thuret (’50), who then first demonstrated the biciliate character of the zodspores of
Saprolegnia, and figured unmistakably the odgonia of the form he studied, which he
called S. ferax. Now followed those accounts by Pringsheim (’51) and DeBary (52),
which mark the beginning of our exact knowledge of the Saprolegniacee, and which
have led to the long series of contributions, the most important of which are quoted
in the morphological and systematic parts of the present paper. The number of these
which we owe neither to the researches nor to the direct influence of these two pio-
neers and masters in the study of the Thallophytes is surprisingly small.

To return to the systematic history of the group: Kiitzing, in his “‘ Phycologia”
(743), places ZL. lacteus, with various other forms not Saprolegniacze and largely
unidentifiable, under the genus Leptomitus, and includes the other forms then known
under three species of Saprolegnia, S. minor, ferax, and xylophila. In his “Species
Algarum” (’49) the same author includes Z. lacteus as before, and enumerates six
additional species of Saprolegnia, most of which are now unrecognizable. Braun
(750) established the species S. capitulifera for a plant with sporangia of the Achlya
type. Robin (’53) mentions only 8. minor and S. ferax; and Pringsheim, in his ear-
liest paper (’51), though describing a Saprolegnia, calls it A. prolifera. It was
DeBary (752) who first again brought forward and applied Nees’ old generic distine-

WITH NOTES ON OTHER SPECIES. 101

tions, and showed the necessity for characters drawn from the sexual organs in spe-
cific determinations. It is to him and to subsequent writers who recognized the cor-
rectness of his position, that we owe our present notions of generic and specific
distinctions. No writer before him appreciated the true specific differences, and none
save Nees, whose insight remained unrecognized for three decades, saw the true value
of characters now recognized as generic. With the single exception of Thuret’s S.
Jerax, no species had previously been described or figured so as to be now recog-
nizable. It is an interesting coincidence that his first botanical publication and tLe
posthumous fragment prepared from his last manuscripts by his successor should
both have dealt with Saprolegniacee.' 3

The history of the great progress in the knowledge of this family during the
past forty years may be traced, as has been said, in the works referred to on other
pages; but certain matters which are now wholly of historical interest may be briefly
referred to here. The discussions concerning the specific value of certain morpholog-
ical differences and concerning the sexuality of these fungi are considered suffi-
ciently elsewhere. But the members of this family have figured prominently in the
pleomorphy craze which foilowed Tulasne’s proof of the pleomorphism of many Asco-
mycetes. The extreme advocates of this doctrine, Bail (60), Hoffman (67), and
Karsten (’69), held that the same plant assumes the form of Saprolegnia in water, or
of Hmpusa in air, when growing on flies. On other substances the same species was
supposed to appear as Mucor, or even as Penicillium ; and in saccharine solutions to
take the Saccharomyces form. Tarlier than these views became popular, similar sug-
gestions had been made. Nees (’31) suggested a connection between Hmpusa and
Achlya ; and Meyen and Cienkowski (’55) affirmed a connection between Jsarza or
Empusa, on one hand, with “Achlya prolifera,” on the other. It is to Brefeld’s
researches (71) and the application of rigid culture methods like his that we owe
the final proof of the incorrectness of this belief.

The history of American studies of Saprolegniacee is briefly told. So far as I
know, Leidy (750) first mentioned “Achlya prolifera,” which he reported having seen
in all stages of development on Ascarids in water. Gerard’s (’78) brief account of
“ §. ferax” in connection with an epizodtic among fish in New Jersey, Hine’s (’78)
observations ona species of Saprolegnia and on Achlya racemosa, and Galloway’s
(91) cytological notes on S. monoica complete the short list.

SYSTEMATIC PART.

The following diagnoses of American species of Saprolegniacee are drawn wholly
from American specimens, except in a very few cases where the incompleteness of

102 THE SAPROLEGNIACEZ OF TILE UNITED STATES,

the material has made it necessary to refer to Huropean descriptions for certain
details. In all such cases the borrowed matter has been indicated by quotation marks.
For species not yet known to be American a brief informal statement of the chief diag-
nostic characters is given to aid the student who may meet with them, since many of
them are likely to be found with us.

Artificial dichotomous keys to all the intelligibly described species are prefixed
to the detailed accounts, in all but the smallest genera, as a practical encouragement
to their study; but they should never be relied on alone for the determination of

species.

SAPROLEGNIACE# Pringsh. (’57).

Aquatic fungi, living as saprophytes or facultative parasites, with usually
branched mycelium ; the hyphe in a few species constricted at intervals, but remain-
ing unseptate except in the formation of reproductive organs. The latter of two
kinds, non-sexual and sexual, both formed from the hyphz and separated from their
vegetative portions by transverse walls. Non-sexual propagation by means of bicili-
ate, often diplanetic, zodspores, produced in cylindrical or swollen sporangia; or very
rarely by homologous non-motile bodies; occasionally also by chlamydospores. Mor-
phologically sexual reproduction by oJjspores developed in typicall y globular odgonia,
one or more from the entire protoplasm of each ojgonium; antheridia on branches of
androgynous or diclinous origin, very rarely on the odgonial branch, uniting with all,
or with only a part of the odgonia, or in several species wholly absent; when present,
usually producing fertilization tubes which remain closed, at least in some species.

Key to Genera.

A. Vegetative filaments with their walls unconstricted....,,.....e0.---«+: Glee omiclaelere caste Meee wes (Saprolegniee) B.
Veretative filaments) deeplyiconstricted atunterval saeeeeccieieseiseieelete inten eieertateae etter irra (Leptomitee) J.
B. Zoodspores normally leaving the sporangium by a common mouth..........- pauonocHdos boss Oaceobaguads sass C.
Zcospores not leaving theisporane ium) by, a Common mothe. ce seeeeeiseletsslelelsieite eset ital siete eile Soe
C. Zodspores swarming separately on escaping from the sporangium,.........+..ececeeee cee cess etree eeeeeee .D.
Zoospores collecting in a hollow sphere at the mouth, on escaping..............-2.20 aleyataeheteiciate/sralsefoiniaiarete F.
D. Zoodspores diplanetic ; new sporangia growing through the empty ones...............0-.--eee o/aimalers winteseererete Ei.
Zobspores monoplanetic ; sporangia renewed by cymose branching........ a bine elsisieceeee s (sie: usm aici PyruHiorsis.
#. Oéospore single, wholly filling the o6gonium......... Son snaaodacboehud ctasHonndooe akdooooe SONS onc Leptolegnia.
Oéspores one or more, not wholly filling the o6gonium.........-....0...000- jedoodeosaccs ++. .+-SAPROLEGNIA.
F, Sporangia usually broader than the vegetative hyphe ; zodspores irregularly arranged..............-- ACHLYA.
Sporangia equaling the vegetative hyphe in breadth ; zodspores in a single file.............+---- APHANOMYCES.
G. Zodspores encysting within the sporangium, afterwards SWarmMing.........2. cece cence cece ec ee este tees eens H.
Zoéspores encysting and germinating within the sporangium, never swarming............+2+0+ seeeesas Aplanes
H, - Zoo3pores set free by the breaking up of the sporangial wall...... <2... .cccscescecccecctccecsencs Thraustotheca.
Zoéspores escaping each by a separate perforation of the sporangial wall, leaving a ‘‘net.’’...-.... DicryucHus.
J, Zodspores swarming separately on escaping......... iis cisiatoveteetelsteletereintets is (ele faiierninteeisiceieicioemiitsisiaiels LEPTOMITUS.

Z Ospores collecting at the mouth of the sporangium, on eScaping........e.ceeeeeeeececeseeeees .APODACHLYA.

WITH NOTES ON OTHER SPECIES. 103
Subfamily Saprolegniec.
Saprolegnia Nees ab Esenb. (’23).

Syn. : ? Conferva pisctum Schrank (1789).
Conferva ferax Gruith. (21).
S. molluscorum Nees ab Esenb. (’23).
Leptomitus clavatus Ag. (24).
ie Serax Ag. (24).
Ht piscidicola Berk. (’33).
Achlya prolifera Auct.
Exsic. : Myc. Univ., 1213 (S. feraz).
Algues de la France, 1195 (do.).

Hyphe rather stout or slender, often not much branched. Zodsporangia formed

from their tips, generally cylindrical or slightly clavate, rarely short and in series ;

the later ones arising within the empty membranes of preceding ones by upward
growth of their basal walls, or rarely beside them by cymose branching. Zoidspores

diplanetic, at first pyriform, with two apical cilia, escaping by a usually terminal

mouth at the apex of a distinct papilla, and swarming separately ; after encystment

and rest becoming reniform swarmers with two lateral cilia; finally encysting again

and germinating. Odgonia terminal or intercalary, never wholly filled by the one or ©

more odspores. Antheridia wholly absent in some species, and always present in

some.

Key to recogmzed Species.

a. Odgonial wall always smooth and unpitted ; oOspores eXCentric.................e eee eee eee S. anisospora.
Odégonial wall pitted, at least in some specimens ; odspores centric..... Bea (oliayer sia teystoverslatessrereie etelereiovevsicre siavale ele(iciels b.
OGgonial wall spiny ; OGspores CENtrIC......- eee cece cree esc c ces ct src eess veces peMnretsteretatetelatsteletsratetetelsvetaterere a

b. Odgonia in moniliform series, early falling apart, not all pitted............. cece cee ee cece rece eee S. monilifera.
Odégonia not separating from the plants before maturity, all more or less pitted............ cc eeeee eens rece eeee c.

ue Ant heridialsoranchesratiached: tOlevetys OOP OMIM ryat-fele cicleilslol=lele) s+ »10) «1 /ele\afelcie\oleis\e e)e\cls)e) »\elcle cls)s) e//e\e\s\eisic/eieielsie'e = « d.
Antheridial branches attached to some or to none of the O6gonia..............--- score cece eect eee eee eeees vie

d. Plants diclinous ; pits small..... BO CODA S OO DOCS HOO OD DD EGO OTTO CT TTT eC S eer wtolerenvave crelevetare S. DICLINA.
AN SyaAN AKO My NOUS Mm pItS plate Cry etelercleleleletelereloleleley=ier-\>reterolslelerelcieclelel= sieretelelictatcistesiets doadeAdo oo KOO OD AdUSsOUNSEOS é.

é. Q6gonial branch short and straight..................... 2aoaKo0000 sre dete eletenedstntetetafefelor-teretetcvelersteieiecaeteiete S. MONOICA.
Oégonial branch usually helically coiled..............++-+00. SOU OCSOCT GHOGHO COCA OIRATOC GEO ceoGne S. spiralis.

me AatheridialabrancHeswotten:d evel Oped taratererrtelsyoi<talaicioictelelatoielsie-ataisisie/s/+i-l- -lelsjelets\nejeleleleieiars e eieis/sjeieieie cis ave < e's S. MIXTA.
Anthendialibranches very, Lave liys OL ME Ver CEVeLOMEU circ: crs isle) e/e'ele}«\s'\0)<)ajale)assl= afelelaleinicte ele cleltie efsleicleleisieiasieiele «levee « g.

g. Antheridium formed just below the odgonium, on the same branch..............-ccceseeseceeeees S. hypogyna.
Antheridia not developed, or very rarely so........ sforaaeloraeiajeierevetelelavetsieha/lelacieie ches isicicielestisiciereietereisiotee cece eee sss h.

h. Odgonia irregular, often in torulose series, with few and small pits................. ce eeee eee eeess S. TORULOSA.
Oégonia globular, or not rarely cylindrical, not in series, with large Pits...........cc..ceeceeeecee ees 8. FERAX.

7. Odspores one or two in an odgonium ; hyphe slender............ wlalsfeleisiafoverstai ace e(eLaats sieveieye eis)e¥e « S. ASTEROPHORA.
Oéspores several in an o6gonium ; hyphe very stout........... stalatateiefefore’oleicparcheyelere his etelarcieinveree S. TRELEASBANA.

A. P. S.—VOL. XVII. N.

104 THE SAPROLEGNIACEZ OF THE UNITED STATES,

SAPROLEGNIA MONOICA Pringsh. (’57).

Syn.: S. ferax Auct. p. p. Ill. : Pringsheim, ’57, Pl. XTX, XX.
8S. dioica Pringsh. (60). Reinke, ’69, Pl. XII.
Diplanes saprolegnioides Leitgeb. (’68). DeBary, ’81, Pl. V, Figs. 11-19; VI, 1, 2.
Achlya intermedia Bail (608), sec. Lindstedt (772). Ward, ’83, Pl. XXII, Figs. 17-22.

Rothert, ’88, Pl. X, Figs. 14.
Pl. XVI, Figs. 37-39.

Hyphe rather stout, often long. Zodsporangia cylindric-clavate.~ Odgonia ter-
minal or rarely intercalary, usually on short lateral branches, globular, their walls
abundantly and prominently marked with large pits. Antheridia long-cylindrical,
uniting with every odgonium, on rather stout branches of androgynous origin, which
usually arise from the main hypha near the odgonial branch. Odspores commonly

not above ten, rarely numerous, centric, their average diameter about 26,.

Massachusetts—Cambridge, Z’release ; Amherst: Alabama—Auburn, Atkinson.
Europe.

This species, obtained by Prof. Trelease at Cambridge in 1881, was first pro-
cured by the writer from a pool containing dead Carex leaves, which bore abundant
masses of Chetophora; and subsequently from a mass of dead leaves and slime at
the bottom of a ditch draining cultivated fields. Among cultures from the Southern
States, it has appeared only once. It does not, therefore, seem to be very abundant
with us; but it is well distinguished by the large and numerous oogonial pits and the
abundant and well-developed antheridia, which are larger and more conspicuous than
those of any other species of the genus, except possibly S. asterophora.

The observation of the diplanetism of the zodspores of this species led Leitgeb
to establish a new genus, Diplanes, for it, although the phenomenon had previously
been observed in species of this genus. Lindstedt gives Achlya intermedia Bail as
a synonym of Diplanes saprolegnioides Leitg., and is followed by Saccardo (88).
Having been unable to examine Bail’s description and figure, I must be content with
following the authors mentioned.

Var. montana DeBary (’88.)
Differs from the type in its slightly or not at all pitted odgonia, on longer
branches. It has not been recognized in America.
Saprolegnia spiralis Cornu (’72.)

This form, which appears to have been recognized only by its author, is said to
differ from S. monoica chiefly in its longer odgonial branches, which are coiled in a

WITH NOTES ON OTHER SPECIES. 105

helix of one or two turns. It is of doubtful autonomy, but, in the absence of fuller
knowledge, may be allowed to stand for the present; although it would hardly appear
to be entitled to more than varietal rank, if well marked.

SAPROLEGNIA MIXTA DeBary (’83).

Syn.: S. feraw Auct. p. p. Ill. : Pl. XVL, Figs. 40-42.
8S. feraz Schroeter (86). —
S. dioica Schroeter (’69).

Hyphe rather slender, not long. Zodsporangia cylindric-clavate. Odgonia ter-
minal or rarely intercalary, on main filaments or lateral branches, globular, with
numerous pits of varying size, but often pretty large. Antheridia cylindrical, rather
shorter and smaller than in S. monoica, of androgynous or diclinous origin, absent
from a part of the oogonia, sometimes from a large part. Odspores up to fif-
teen or occasionally more than twice that number, centric, their average diameter
about 26p.

Pennsylvania—Philadelphia, Keller. Mississippi—Starkville, Whzte: Louisiana
—Bayou Tortue, Langlois. Europe.

J have not yet with certainty recognized this species in Amherst cultures, but
have received it from three sources; which indicates that it is widely distributed and
not uncommon. ‘The materials for two of the cultures containing it were taken from
small pools, while the third and most abundant specimen came from Algz and Lem-
ne growing in Bayou Tortue, near St. Martinville, La.

The species is rather. vague and unsatisfactorily defined, as DeBary has
remarked (’88). It is intermediate in several respects between S. monoica and SW.
ferax, and might seem to afford ground for regarding all these as forms of a single
species, as Pringsheim does. Having found WS. monoica and WS. ferax to be well
marked and constant before meeting with this species, I was for some time skeptical
concerning it, thinking it might have originated in a mixture of those two. But the
_ receipt of material from distinct sources which could be referred to neither of those,
and which shows constantly the characters above stated, in successive generations,
has convinced me that the species is well founded and appropriately named. The
smaller and less abundant antheridia, not always of androgynous origin, and the
usually less numerous and less conspicuous pits of the odgonial wall chiefly distin-

106 THE SAPROLEGNIACEH OF THE UNITED STATES,

guish it from S. monoica. Its hyphe are also rather slenderer and more flaccid than
those of the latter.

The description of S. ferax given by Schroeter (786) is clearly not applicable to
that species, but very well characterizes the present one. It must be considered,
therefore, that this author’s S. ferax belongs here as a synonym; and, if so, then
also his 8. diovca, which he quotes (’86) as a synonym of his S. feraz. Fortunately,
the name S. dzovca had been used for another plant by Pringsheim (’60) and there-
fore cannot be retained for this one, although Schroeter’s use of it antedates DeBary’s.

SAPROLEGNIA FERAX (Gruith.) Thuret (750).

Syn. : S. feraw Auct. p.p. Ill. : Thuret, °50, Pl. XVI.
Achlya prolifera Pringsh. (51). Pringsheim, ’51, Pl. XLVI-L.
S. Thureti DeBary (’81). Pringsheim, ’74, Pl. XVIII, Figs. 5 and 11.

DeBary, 81, Pl. V, Figs. 1-10.
Rothert, ’88, Pl. X, Figs. 1-13.
Pl. XVI, Figs. 43-45.

Hyphe of medium size. Zodsporangia clavate-cylindrical. Odogonia terminal
or sometimes intercalary on main hyphe or lateral branches, globular or not rarely
cylindrical, their walls very thickly and conspicuously marked by large pits. An-
theridial branches and antheridia never developed or extremely rare. Odspores up to

twenty in an odgonium, or sometimes more (“40 to over 50,” DeBary), centric, their

average diameter about 26».

Massachusetts—Amherst : Wisconsin—Madison, release: Missouri—St. Louis,
Trelease: Kentucky —Lexington, comm. Keller. Europe.

In Wisconsin this species was obtained by Prof. Trelease from Algze collected
in a ditch, and at St. Louis it grew spontaneously on flies in water. The Kentucky
specimen sent by Dr. Keller was obtained from Algze, chiefly Hydrodictyon, collected
in a pool in a cemetery at Lexington. I have never obtained it in Amherst from
open-air materials, but have found it on flies thrown in water taken from the room
for tropical aquatics in the plant house of the Massachusetts Agricultural College.
This specimen was a reduced form in all respects, although undoubtedly of this
species.

This plant seems, then, to be more common in the Western than in the Eastern
States. The absence of antheridia, the rather common occurrence of cylindrical
odgonia, and the very conspicuous pitting of all the odgonia mark the species unmis-
takably. It was first sharply distinguished and characterized by DeBary (’81), who

WITH NOTES ON OTHER SPECIES. 107

ealled it S. Thureti, recognizing it as the form whose oogonia were first figured by
Thuret. But although, as has been remarked, the latter author had no understanding
of the true specific limits among these fungi, there is still no reason for refusing to
restrict to his form Gruithuisen’s name, by which he called it, and which had previ-
ously been used in a much wider application.

It has already been pointed out that the S. ferax (Gruith.) of Schroeter (’86) is
probably S. muxta DeBary. The description given in Saccardo’s Sylloge (’88) under
the name of S. ferax is quite unrecognizable. It is noteworthy that this work per-
petuates the old myth that Hmpusa is an imperfect state of S. feraa.

It is difficult to cireumscribe what DeBary has called the ferax group of Sap-
rolegnie, since so many species show relations with each other at various points,
while remaining, within their limits, very constant. The three species already
described constitute, however, the most closely united group, and it is perhaps better
to limit the term to them, if it is to be used at all, than to apply it to an assemblage
of species necessarily much larger if at all increased. In these species, taken in the
order in which they are here placed, there is observed a progressive reduction in the
antheridia, and an increase in the normal size of the oégonia and in the number of
odspores ; while the average size of the latter varies little, although extreme speci-
mens may vary as much as 5, on either side of the average.

Saprolegnia hypogyna Pringsh. (’74).
Syn.: S. feraz, var. hypogyna Pringsh. (’74). Ill.: Pringsheim, ’74, Pl. XVIII, Figs. 9, 10.

This species, which has been studied by Pringsheim and DeBary (’88) and is
doubtless well founded, differs from all other known Saprolegniacee in producing
antheridia without special antheridial branches. A second portion of the odgonial
branch is cut off just below the odgonium and constitutes the antheridium. Its
upper wall, which is also the basal wall of the oogonium, grows up, as a fertilization
tube, into the cavity of the latter. The odgonia show, in their form, in the pitting of
their walls, and in the structure and number of their odspores, near relations with the
ferax group, but the species is at once recognizable by the peculiarities above men-
tioned. It is not yet known to oceur in America.

SAPROLEGNIA TORULOSA DeBary (’81).

Ul.: DeBary, ’81, Pl. VI, Figs. 3-17.
Pl. XVI, Figs. 46-49.

Hyphe rather slender. Zodsporangia from cylindric becoming clavate, fusiform,

or nearly globular, often in torulose series. Ovogonia globular, ovate, pyriform, or

108 THE SAPROLEGNIACE OF THE UNITED STATES,

cylindrical, terminal or intercalary, commonly in torulose series, their walls more or
less abundantly marked by small pits, and yellowish brown when old. The members
of a series may form, some sporangia and others oogonia. Antheridia very rarely
present. Oéspores as many as twelve, or rarely more, in an odgonium, centric, their

average diameter about 25p.

Massachusetts—Amherst : New Hampshire—Mt. Washington, Zhaxter: Louis-
iana—St. Martinville, Langlois. Europe. |

A characteristic species which is not very uncommon with us, apparently. In
my Amherst cultures it has appeared twice, once from the very prolific mossy pool,
mentioned elsewhere, and again from alge (Spirogyra) from a small boggy area by
a brook. Prof. Thaxter has sent me specimens developed spontaneously on
Lepidopterous larve in the “Alpine Garden,” on Mount Washington; and Mr.
Langlois has obtained it from a ditch in Louisiana. It shows some points of affinity
with the ferax group, as here limited, yet is very distinct. The antheridia have not
disappeared quite so completely as in S. feraz; and the odgonia contain less numer-
ous odspores, while their walls are much less pitted and are more deeply colored when
mature than in any of the previous species. American specimens do not quite meet
DeBary’s character, “mit wenigen oder ganz ohne Tiipfel,” as they always have, so
far as my observation of a large number of individuals goes, some pits, and often a
considerable number; but these are always small.

The best diagnostic character of the species is found in the successive formation of
walls in the same filament, cutting off as many segments, which may all become
sporangia, or all oogonia, or partly each. In the latter case, the terminal members
usually become odgonia. ‘The odgonia remain attached to the plant until the hyphz
become disorganized, and therein differ from those of the next species. No better
evidence could be desired of the lack of fundamental difference between sporangia
and odgonia than the indiscriminate formation of both from exactly similar members,

at the same time, here observed.

Saprolegnia monilifera DeBary (’88).
Ill. : DeBary, ’88, Pl. IX, Fig. 6.

DeBary separates this species as a distinct type from the other members of the
genus, although, judging from his description, it would seem to represent a further
development on the lines of S. torulosa. Its odgonia are formed in somewhat more
definite moniliform chains, all of whose members appear to have the same fate.

WITH NOTES ON OTHER SPECIES. 109

Their walls are occasionally pitted, and no antheridia are developed. A striking
feature is the separation of the odgonia from the plant and from each other, often
at a very early stage, so that they lie free in the water and complete their develop-
ment independently.

The species presents a transitional feature leading towards Achlya, or a rever-
sional feature towards the commonest condition in the family, in that many of the
later sporangia are produced by cymose branching, instead of by the usual method
for Saprolegnia. It has not been seen in America.

SAPROLEGNIA DICLINA nom. noy.
Syn.: S. dioica DeBary (88). Ill.: DeBary, ’88, Pl. X, Figs. 12, 18.
nec 8. dioica Pringsh. (’60), nec Schroet. (69). Pl. XVI, Figs. 50-53.

Hyphe slender, not long. Zéosporangia nearly cylindrical. Odgonia terminal
on main hyphe, or less commonly on lateral branches, typically globular, their walls
marked with small pits, which are often few and inconspicuous. Antheridial branches
long, flexuous, and very slender, of diclinous origin. Antheridia on every oogonium,
ovate or short clavate, often very abundant and covering much of its surface, some-.
times rather few. Odspores most commonly ten or twelve, sometimes twenty or

more, and often only four to six, centric, their average diameter about 25,.

Massachusetts—Amherst: Pennsylvania—Philadelphia, Keller: Alabama—
Auburn, Atkinson: Louisiana—st. Martinville, Zanglois. Hurope.

This is unquestionably our commonest Saprolegnia. I have obtained it six or
seven times in cultures from small pools, spring-holes, and similar places, and have
received it from most of my correspondents, as above shown. It is readily identified by
the small and fewer pits of the odgonial wall, as compared with those of the ferax
group; and especially by the antheridia, which are always present, as in S. monovca,
but smaller, of different shape, and on slenderer branches than in the latter species ;
while the branches are always of diclinous origin. When the plants become old,
these delicate antheridial branches often disappear, leaving the antheridia adhering
to the oogonia without indication of their origin. ‘This may, indeed, happen in other
species, but not so commonly or so early as in the present one.

A reduced form of this species, hardly worthy of varietal rank, occurs frequently.
It is distinguished chiefly by its smaller size, and by a reduction of the number of
both odspores and antheridia to a very few (Fig. 53).

The species, as limited in America, is exactly S. dioica DeBary, except that I

110 THE SAPROLEGNIACEZ OF THE UNITED STATES,

have never seen the intercalary barrel-shaped odgonia, said by that author to occur
sometimes. It should bear his name, but for the fact that that name had previously
been applied by Pringsheim (’60) to S. monotca attacked by Chytridiaceous para-
sites; and this previous use of the name, although it can stand only as a synonym,
should debar its further use, in the interest of clearness and accuracy. The use of
the same name by Schroeter (’69) for apparently another species has been already
alluded to. It may be, as DeBary intimates (’88), that this species has been included
by some authors under the name S. diozca ; but there is not the least evidence that
the original author of that name even knew it. In order to change its name as little
as possible, and yet sufficiently, I propose for the species that of S. diclina, which
refers to the same peculiarity as did the former one.

An error which has been overlooked in reading the proof of Saccardo’s Sylloge
(’88, p. 269) makes what is intended for S. dioica read S. divisa. The description
which follows refers to Pringsheim’s pseudo-species.

Saprolegnia anisospora DeBary (’88).
Il.: DeBary, ’88, Pl. 1X, Fig. 4.

This European species takes its name from the fact that its sporangia are of two
kinds, producing respectively large and small zoospores. These are said to agree per-
fectly in structure and development, but the larger are of about twice the diameter
of the smaller, which are like those of other species of Saprolegnia. The odgonial
walls are unpitted and the antheridia agree with those of S. dzclina in their form and
in their diclinous origin. This is the only known Saprolegnia which has excentric
oospores. DeBary well remarks that the species deserves further study. ,

SAPROLEGNIA ASTEROPHORA De Bary (’60).

Ill. : DeBary, ’60, Pl. XX, Figs. 25-27.
DeBary, ’81, Pl. VI, Fig. 18-29.
Pl. XVU, Figs. 54, 55.

Hyphe slender, “with cylindric-clavate zodsporangia.” Odgonia terminal,
globular, with several or many rather long, blunt outgrowths of the wall, giving it a
starlike appearance ; the wall unpitted. Antheridia “usually present,” on branches
arising just below the odgonia from the odgonial branches, short-clavate, applied by
their ends. Odspores commonly single, sometimes two or rarely three, centric, thick-

walled, their diameter about 30,.

WITH NOTES ON OTHER SPECIES. 111

Massachusetts—Cambridge and Wood’s Holl, Zrelease. Europe.

I have never had the opportunity of studying this species alive, and hence arises
the necessity for referring to DeBary’s description (’88) for some details. It
occurs in preparations made by Prof. Trelease from cultures made in Hastern Massa-
chusetts, and must therefore be included in our flora. It has hitherto been the only
known member of the genus with spiny oogonia, and is readily distinguished from
the second such species, next to be described, by its globular and few-spored odgonia,
borne on slender threads. |

SAPROLEGNIA TRELEASEANA §p. nov.

Ill.: Pl. XVI, Figs. 56-59.

Hyphe very thick. Zodsporangia cylindric, rare. Odgonia terminal or inter-
calary, on main hyphee, elliptical or globular, when terminal usually ending in a
strongly developed apiculus; their walls not pitted, but with rather scattered blunt
outgrowths of varying length, oftenest short. Antheridial branches short and slen-
der, arising just outside the odgonial wall, one or several to each odgonium, or
sometimes wholly absent. Antheridia short-cylindric or slightly clavate. Odspores
numerous, averaging ten or twelve in an odgonium, centric, their diameter from 25
to 35p.

Massachusetts—Wood’s Holl, Trelease.

It isa great pleasure to dedicate this very striking species to its discoverer,
Prof. William Trelease, of St. Louis, whose early studies of our Saprolegniacece were
unfortunately cut short by other engagements. ‘This is done as a slight acknowledg-
ment of the valuable additions to the present paper which are due to his generosity,
and in recognition of the high character of his work as a botanist.

The species was obtained by him in 1881 in cultures with material from Wood’s
Holl, Mass., and he has communicated all his notes and material to the writer. It
has very coarse and freely branched hyphz which often considerably exceed 100, in
diameter at the base. The sporangia are so rare that Prof. Trelease observed
only one (Fig. 56), and I have been unable to find any in his material. The size
and manner of branching of the hyphae, as well as the appearance of the odgonia,
strongly suggest the genus Achlya, but the single sporangium seen showed that the
spores escape as in Saprolegnia. In the structure of its sexual organs this plant
resembles quite strikingly that to be described later as Achlya papillata, but it is

A. P. 8.—VOL. XVII. 0.

112 THE SAPROLEGNIACEZ OF THE UNITED STATES,

much more robust than that and sufficiently distinct otherwise, aside from the differ-

ences in the sporangia.

SPECIES INQUIRENDZ&.

Saprolegnia androgyna Archer (’6%.) See Notes on Aplanes.

Saprolegnia xylophila Kitz. (43). As various members of this family grow
readily on decaying wood in water, it is probable that this name refers to some of
them. As it antedates the discovery of the sexual organs, Kiitzing’s figure shows
only the zoosporic stage, and the name cannot be referred to the synonymy of any
particular species.

Saprolegnia corcagiensis Hartog (’87) is said to have the constrictions and
zoosporangia of Leptomitus lacteus, and odgonia with pitted walls (“fenestratis ”).
It has been recognized only by Hartog and needs to be more completely charac-
terized and further investigated.

Saprolegnia quisquiliarum Roumeg. (791) has not to my knowledge been fully
described, but is based on specimens issued as No. 5932 of the “Fungi Gallici.”
An examination of one of the specimens issued, made partly by my friend, Mr. A.
B. Seymour, and partly by myself through his kindness, failed to discover anything

Saprolegniaceous.

SPECIES EXCLUDEND &.

Saprolegnia mor Kiitz. ?43) is probably an Hmpusa. |

Saprolegnia DeBaryi Walz (’70) is probably a species of Pythium.

Saprolegnia siliqueformis Reinsch (’78) is Monoblepharis prolifera Cornu,
according to Cornu (77).

Saprolegnia Schachtii Frank (’81) is probably also a Pythium.

Saprolegnia Libertwe (Bory) Ktz. (49) and three other names published by
Kiitzing at the same time, viz., S. candida, S. tenuis and S. saccata, are followed by
descriptions so imperfect as to have no individuality and no value.

Saprolegnia mucophaga Smith (Gard. Chron., XX, 781; 1883) and

Saprolegnia philomukes Smith (Gard. Chron., X XII, 245; 1884) do not belong
to this family. They may be forms of Pythiwm.

WITH NOTES ON OTHER SPECIES. 113°

Leptolegnia DeBary (’88).

Differs from Saprolegnia in that the odgonium contains a single odspore which
completely fills it.
7 Leptolegnia caudata DeBary (’88).
Ill.: DeBary, ’88, Pl. IX, Fig. 5.

_ The single known species of this genus has narrow sporangia, ovate ojgonia on
short racemose branches, and antheridia, usually one to each ojgonium, on branches
of diclinous origin. It was obtained by DeBary from two different cultures from
German mountain lakes, and is known only from these.

Pythiopsis DeBary (’88).

Hyphe slender, much branched. Zodsporangia formed from their tips, globular,
oval, ovate, or short-clavate, the later ones arising by cymose branching of the
hyphe, either sessile or on long branches. Zodspores ovate, apically biciliate,
escaping by a usually terminal mouth at the apex of a distinct papilla, and swarm-
ing separately ; after encystment germinating without a second swarming stage, 2. e.,
monoplanetic. Odgonia and antheridia abundantly developed.

Pytuiopsis cymosa DeBary (’88).

Ill.: DeBary, ’88, Pl. IX, Fig. 1.
Pl. XVII, Fig. 60-68.

Hyphe slender, short. Zodsporangia from globular to short-clavate. Odgonia
commonly terminal and globular, their walls unpitted, sometimes with a very few
blunt outgrowths. Antheridia clavate, one, or rarely more, on each odgonium,
usually arising just below its basal wall, rarely of diclinous origin. Odspores single,
or very rarely two, in the odgonium, excentric, with several oil-globules, their

average diameter about 18.

Massachusetts—Amherst. Hurope.

The present interesting species, previously known only from DeBary’s account,
and obtained by him from a snow-water pool in the Vosges mountains, appeared in
two of my cultures in March, 1892. Both were obtained from Algz consisting
chiefly of Spirogyra sp. One, from a ditch, had been kept in a jar in the laboratory
since the preceding November, and had yielded A. apiculata, Aph. scaber, and Dic-

114 THE SAPROLEGNIACE# OF THE UNITED STATES,

tyuchus sp. The other was freshly collected and gave also A. cornuta, A. mega-
sperma, and S. torulosa.

I have not followed the zodspore from its encystment to its germination; but,
as the spores germinate freely in cultures which contain no trace of empty mem-
branes, such as are seen with germinating diplanetie spores, there can be no doubt
of their monoplanetism. The general appearance of the plant and of its sporangia
strongly suggests a Pythium, as intimated in the generic name. The formation of
the zotspores does not appear to follow the course above described as characteristic
of the family. I have not been able to study the process in detail, but it seems to
be much simpler than that usual among Saprolegniacee. While the escape-papilla
may appear more than three hours before the exit of the spores, no change is evident
in the protoplasm of the sporangium until fifteen or twenty minutes before that
event. The separation of the spores within the sporangium is very slight and I
have seen nothing corresponding to the two separation stages, with an intermediate
stage of swelling up. One might regard tbis as leading towards the simpler z0é6-
spore formation of the Peronosporee, but for the fact that the zodspores are terminally,
and not laterally, biciliate. The whole question deserves careful comparative study.

The outgrowths of the odgonial wall are only exceptionally rather long ; and in the
great majority of cases are not at all developed. Ina very large number of odgonia
examined, I have seen only one (Fig. 67) with more than a single odspore. DeBary
states that three sometimes occur. He also mentions the presence of as many as
four antheridia on an odgonium. Amherst specimens have rarely had more than
one each and never more than two. I have seen, also, the peculiar hyaline outer
layer surrounding some odgonia, which was mentioned by DeBary; but cannot
regard it as due to an extrusion of periplasm, as is suggested in his account (’88),
since no periplasm is observed in other o6gonia, and because it may occur on young
oogonia before the formation of the odsphere, as well as on adult ones. I am, how-
ever, quite unable to explain its origin. On young odgonia it appears to be thicker
than on older ones, but it has been seen at all in my cultures only exceptionally.

Achlya Nees ab Hsenb. (’23).

Syn.: Byssus aquatica F). Dan. (1780). Exsic.: Algues de la France, 238 (A. prolifera).
Vaucheria aquatica Lyngb. (19). Rabh., Algen Sachsens, 242 (do.).
Hydronema Carus (’23).

Leptomitus prolifer Ag. ('24).
Saprolegnia capitulifera Braun (’51).

Hyphz usually stout, sometimes slender. Zodsporangia formed from their

WITH NOTES ON OTHER SPECIES. 115

swollen apices, usually thickest near the middle, @. ¢., fusiform ; the later ones arising

on lateral branches from below the basal walls of the earlier ones, their successive

formation resulting in a sympodial thread with apparently lateral sporangia. Zoé-

spores ovate or pyriform, at least sometimes, and probably always, apically biciliate,

escaping by a single, usually terminal, mouth formed at the apex of a distinct

papilla, and immediately becoming encysted and aggregated into a hollow sphere;

after resting, swarming a second time in the laterally biciliate form; finally encyst-

ing again and germinating. Odgonia terminal or intercalary, one- to many-spored.

Antheridia seldom wholly absent, often always present.

Key to recoguzed Species.

Ooronianwithypltte de wall Sirelesr cistern cersiaiey o:-veensiatsrvele (ela o/s ereveietct stare ayer leteievsilereys) \eleieicia\siste erctels <W s)s/e/siaisiaisierajaiore 30000 d.
Woconialbwall sim ot pitted erreyerteiei- eicterct Veretch ek teys ok fens) Ne ooio! ety Loto nies ere fos cla) sroue/e\cve\syop1s\ajs\ale/ale, Ave! sf Aajers <1 oisye-m vel osarece C.
IPO MIS CHOTMOME, sdosooccnoe poadseoooNaad enucddond Saud GOOD COD aE sdb oOC Gon SB Benos yeon beacnodaas A, prolifera.
Plants androgynous......... Go ooosbuenepeosadeanosavendcdnocUD Odd op DGOOD aUbOGCDOUUGCOuOCDE A. AMERICANA.
Woe OMIA NYSEOOL Wall Stepeae separa arate eletete otstolaoterteraiete)<atelefetelerei=isie/ lero efafaler= efelelca\ele/eiels oil sfeyel a\a)a\sle/e\ violet pooonsaeueth
Ocgonianwith*spinyswallss. ee \-o a cliec os ee cle olan = «sa 016 OUORUS ds BO SOR OOO HS bESbd Goa u Capo aEHnerooceaeac a.
Plants strictly Giclinous, ....... 2.2.02... 202s ecnecces erect sce e etree e sent ssannccscrcesssees A. OBLONGATA. |
Plantsratseastpancl yan drOcymOuUSwerse ile) -yelelelislalolelielleiaieisieieielele) ier clelsie s/c 2090000 poodonsenosqnousegoodd S00
OPSCORES BIOENG iN OF MOG, Soc0 csocscasooanne 100 bop OOUN Go bbD DU dood Coa oD KUOD COO Oo eud Sco nae onouoE ifs
OGsnoresyayera smo Veron OS Sieve rol <lefedeells Yel leteryeheereroiciadsherelie/oveie ielere elelol-to olelateyelelalclcieysselele) e/eters)t/ef-folel~ </ele) = =1s/s/-)eYele © g-
OGgonial branches short; odspores exCentric.....- 2.6... ccc cee eee ee tee eee tet eee ees A. DeBaryana.
OsronialWbranchesMone;POOsSpOKES ICOM bLIC s yoelate ats alole mrelorereteleleatalalsielelell=\elol=!alelelol=ie/sle) </e)=is eieleleieiersial« A. POLYANDRA.
Odspores over 40, in diameter ; antheridial branches much branched...............+-22.2+005: A. MEGASPERMA.
Oéspores less than 40, in diameter ; antheridial branches rarely branched. .............22000 +20 eeeeeeeeeee: h.
Odgonia usually apiculate; antheridial branches oftenest from the main hypha .................. A. APICULATA.
Obgonia not apiculate ; antheridial branches always from the odgonial branches.................. A. RACEMOSA.
Antheridia on at least some o0gonia.................-5.- eretevetetelelelarehete sckersicrterevacy stale eteretore reschertesnicr=’ cierelcicish sisters’ k.
ASRIIO MOND, WAOUN? DDE sodacnnd06606 905800000080 00 Sud gOD GUD OOO DOnD COD UB eUEneenOSenoee as cco donc sCoremn 0.
Obgonia usually lateral at the ends of recurved branches................cscecesseeececscce cece seced A. recurva.
O6gonia terminal or intercalary, on straight branches. ............... 000.2 e ccc c cece eee c eee e eee e eect ee ee ene l.
Odgonia globular ; antheridia on each one....... .....seeeeeeeeeecsseeee doms00 DUedIOGKNSd0dUSOCGKOdaUDaSCDE mM.
Ooroniaroftenest elliptical; antherieia mot On! allen coin ielelelsre clalele»)<1< 1-110 le) e\sleleieiele eleieie «leislele)> clcisie cise «iv)sieie's se cieis n.
Odspores averaging less than five ; antheridial branches very short.............. A. RACEMOSA var. STELLIGERA.
OGspores averaging more than five; antheridial branches long...............22-.eeeeeeeseeeeees A. oligacantha.
Omenors Sa2, MANE BODO. ce ohodoqgsg00500G0s0000 00 00 000bDbb0DODDGOGGdOb0GERnE srerate\els ateie A. PAPILLOSA.
OGdspores 1-3, often elongate.............0e.-005 Lifebeat tale Acieteie oie relsieia elevate a ata teretesehcyaseracarete BA Mane cheers A. spinosa.
Odgonia with rather sharp spines ; odspore Single....... 2-2. sees e ee rece reece cee sreeeeeneeeseeseeee A, stellata.

Oégonia with blunt spines ; odspores one tO thre€......... 2. cere eee nee e eee eee tee e eee cece eeee A. CORNUTA.

116 THE SAPROLEGNIACEZ OF THE UNITED STATES,

Achlya prolifera (Nees ab E.) DeBary (752).
Ill.: DeBary, ’52, Pl. VII, Figs. 1-28.
DeBary, ’81, Pl. II, Figs. 1, 2, and IV, 1-4.

This is the commonest European species, but it is doubtful if it has been
seen in this country. Hither it or the almost equally common A. DeBaryana
appears very frequently in cultures, there: It is clearly distinguished by the abund-
antly pitted walls of its ojgonia, which resemble those of the next species, and by its
numerous and long antheridial branches of diclinous origin. Fungi reported under
this name in American catalogues have belonged probably to the next or to other
species.

From the fact of its abundance this species is rather more likely than any other
to have been the one which Nees studied and called A. prolifera, although we have
no means of knowing if this is actually the case. Under these circumstances there
was no obligation to continue the name, but DeBary has chosen to do so by restrict-
ing it to this species; and, since it is the first name applied to the species, definitely
recognized as such, and has been applied to no other recognizable species, it must
stand. It is true that DeBary did not clearly characterize the species in the modern
sense until 1881; yet in his earlier paper (52) he described the pitted — or, as he
then thought, perforated — walls of the ojgonium; and as this is the only known
European Achlya of that character, his description sufficiently marks the species, and
the earlier date should be quoted for it.

ACHLYA AMERICANA sp. nov.

il. : Pl. XVI, Figs. 69-73 (also on Pls. X[V-XVI).

Hyphe stout, not very long. Zodsporangia very abundant, rather short and
thick, slightly fusiform. Odgonial branches short, erect, racemosely arranged on
the hyphe. Odgonia terminal and globular, or rarely interealary, their walls much

pitted. Antheridial branches numerous, branching, arising from the main hyphe
between and near the odgonial branches. Antheridia very numerous, cylindric or
somewhat clavate. Odspores from one to fifteen in an odgonium, usually five to nine,

excentric, their average diameter about 22,.

Massachusetts—Amherst: Pennsylvania—Philadelphia, Keller: Alabama—
Auburn, Atkinson: Louisiana—St. Martinville, Langlois.
It is rather remarkable that our most abundant member of this genus, and indeed

WITH NOTES ON OTHER SPECIES. Vales

of this family, so far as the writer’s observations go, while closely resembling the two
commonest European species, combines their characters in a peculiar manner. Like
A. prolifera, our form has o6gonia with abundantly and invariably pitted walls; but,
like A. DeBaryana, its antheridial branches are of androgynous origin; and, like
both, its odspores are of excentric structure. The pits of the odgonial walls are not
conspicuous as in the Saprolegnie of the ferax group, although they are usually
of considerable size; but treatment with the chloroiodide of zine always brings them
out, as numerous transparent areas in the elsewhere deeply colored membrane. The
antheridial branches are not so long nor so luxuriant as those of A. DeBaryana, as
figured by DeBary (81). They usually arise quite near the odgonial branches, very
rarely even from the latter, which is said by DeBary never to happen in the last-named
species ; and the antheridia are rather shorter and envelop the odgonia less than is the
case with the other.

These rather slight, but very constant, differences seemed at first to invalidate the
distinction between the species called by DeBary A. prolifera and A. polyandra, and
to indicate that they, with the present, are forms of a single variable species. But
the very positive statement of so reliable an observer as DeBary as to the constancy
of the characters of his two forms,* and the abundant evidence of repeated cultures
from widely separated sources of the fixity of the present one, have left no alternative |
but to consider the three as distinct, though closely related, species, forming a series
whose middle member is our American representative, and which may be termed
the prolifera group.

I have met with this species in no less than twenty cultures from clean waters
of every description, and from various parts of the country. It is the form referred
to by the writer in an earlier note (791) as “‘a form related closely to A. polyandra
(perhaps that species) ;” and is that in which I first convinced myself of the pres-
ence of cilia on the escaping zodspores of Achlya.

Achlya DeBaryana nom. nov.

Syn. : A. polyandra DeBary (81). Ill. : DeBary, ’81, Pl. IV, Figs. 5-12.
Ward, ’83, Pl. XXII, Figs. 1-14.

This is, as already stated, one of the commonest European species, but it has not
been recognized in America. It has smooth, unpitted odgonia and long, branched

* J am indebted to Prof. Alfred Fischer, of Leipzig, who has had the opportunity of studying DeBary’s material,
for a full confirmation of that author’s statements concerning these species.

118 THE SAPROLEGNIACEZ OF THE UNITED STATES,

antheridial filaments of androgynous origin, but agrees very closely in other respects
with the two preceding species. As above indicated, it is the A. polyandra of
DeBary, but it is clearly not the species to which that name was given earlier by
Hildebrand (’67). DeBary appears to have believed that his species was that intended
by Hildebrand; but, as will be fully shown later, this is not the case. And, since
Hildebrand’s species was pretty carefully described, it is perfectly recognizable.
Hence the name A. polyandra belongs to it alone, and DeBary’s species is left with-
out aname. I therefore propose for the latter the name A.De Baryana, in honor of
the profoundest student of the Saprolegniacee, to whom so large a part of our knowl-
edge of the family is due.

ACHLYA MEGASPERMA Sp. Nov.

Ul: Pl. XVII, Figs. 74-77.

-Hyphe stout, long. Zovdsporangia thick, fusiform, freely developed. Odgonial
branches short and straight, racemosely arranged. Odgonia terminal, globular, with
smooth and unpitted walls which are strongly thickened. Antheridial branches often
arising near the odgonial branches, but apparently never from them, much branched,
often producing no antheridia. The latter absent from many odgonia, from one to
several on others, short-clavate. Odspores two to eight, commonly four to six, in an

odgonium, centric, very dark when young, their average diameter 45+.

Massachusetts—A mherst.

Cultures from Spzrogyra, dead leaves, ete., taken from a boggy spot by a small
brook, are the only ones which have yielded the present well-marked species. The
sporangia recall, in form and abundance, those of A. Americana, but the hyphez are
rather stouter and more vigorous than in that species. The very thick-walled
oogonia, often without antheridia, and the very large odspores, the largest known in
this family, sometimes exceeding 50, in diameter, distinguish it clearly from any
other form. The thickening of the odgonial wall is not perfectly even, but its inner
surface is somewhat irregular (Fig. 77) from unequal deposits of material. The pro-
toplasm of the young odgonia and the odspheres formed from it is very dense and
dark colored, surpassing in this respect even that of A. apiculata. The plant is
androgynous, but many of the smaller branches, which resemble in every other
respect antheridial branches and strikingly suggest those of A. DeBaryana, fail to
develop antheridia, and remain unattached to odjgonia. Branches which do bear

WITH NOTES ON OTHER SPECIES. 119

antheridia are otherwise similar to these. The antheridia which attach themselves to
a given odgonium may or may not arise from the same hypha with it, though such is
perhaps more often the case.

The precise systematic position of the species is perhaps open to discussion, but
it presents points of resemblance and probable relationship with both the last and the
following species.

ACHLYA POLYANDRA Hildeb. (’67).

Syn.: A. gracilipes DeBary (88). Ill.: Hildebrand, ’67, Pl. XVI, Figs. 7-11.
DeBary, ’§8, Pl. X, Figs. 2 and 6.
Pl. XVII, Figs. 78-81. °

Hypheze stout, long. Zodsporangia often not abundant, secondary ones rare,
nearly cylindrical. Odgonial branches usually very long and often recurved at the
tip, racemose. Odgonia terminal, globular, with smooth and unpitted walls.
Antheridial branches arising chiefly from the odgonial branches not far from the
odgonia, often branched. Antheridia one to several on each odgonium, short-clavate.
Odspores five to twenty-five, usually ten to fifteen, in an odgonium, centric, their

average diameter 27,.

Massachusetts—Amherst. Europe.

First obtained in spring from Algze from a temporary rain-pool in a depression
in a grassy field, this species appeared later in a culture from Conferve and Vau-
cherie, taken from a running brook. Its numerous odspores, very long odgonial
‘branches, usually recurved at their tips, with the branched antheridial threads
arising from them and bearing small and short antheridia, distinguish it from related
forms. It appears to be rare with us, as I have never seen it from any other locality
than Amherst, and only twice there.

It is especially interesting as having been the subject of a misunderstanding
which has led to a confusion in synonymy that I have here attempted to correct. It
was undoubtedly this species which Hildebrand described (’67) as A. polyandra.
As has been already pointed out, DeBary gave the same name (’81) to a distinct
species which he recognized as differing from Hildebrand’s description, but thought
to be probably his species. At the time of the completion of the paper quoted,
DeBary had probably never seen this form, as his Jater paper (’88) states that he
first obtained it in January of 1881, the year of the publication of the earlier one.

ACESS. VOl. Vil. P.

120 THE SAPROLEGNIACEZ OF THE UNITED STATES,

And while he did study it, he failed to notice its correspondence with Hildebrand’s
figures and description, and therefore named it anew iA gracilipes. But no one who
will carefully compare the figures given by both authors will, I think, seriously ques-
tion that they represent the same species. Again, Hildebrand states that secondary
sporangia are not produced in his A. polyandra, a statement that DeBary (81) dis-
putes as untrue for his A. polyandra. But in his description of A. gracilipes (’88),
DeBary says that secondary sporangia are only sparingly developed, a statement
which I can corroborate for American specimens. ‘The two descriptions agree in
all other essential points, so far as they are comparable; and the evidence seems
completely satisfactory that the correct synonymy of this distinct species is as above
given. ;

The species shows as many points of affinity, perhaps, with A. DeBaryana and
A, megasperma as with any others, but differs from them too widely to permit us to
suppose any very recent common ancestry.

ACHLYA APICULATA DeBary (88).

Tll.: Ward, ’83, Pl. XXII, Figs. 15, 16.
DeBary, ’88, Pl. X, Figs. 3-5.
Pl. X1X, Figs. 82-86, and XV, 26, 27.

Hyphe stout, often long. Zodsporangia fusiform, abundant. Odgonial branches
somewhat elongate, usually hooked or recurved, racemose. Odgonia terminal, globu-
lar or oval, oftenest with a distinct apiculus, rarely intercalary, their walls smooth
and unpitted. Antheridial branches rather stout, mostly unbranched, from near the
base of the odgonial branch, or sometimes from that branch. Antheridia one to
several on each oogonium, short-clavate. Odspores one to ten, commonly three to

five, in an odgonium, centric, their average diameter about 36y.

Massachusetts—Amherst: Alabama—Auburn, Atkinson. Europe.

So far as Amherst is concerned, this species is the most abundant after 4.
Americana. It has appeared in several cultures from various pools and ditches, and
is not to be confounded with any other species. Its sporangia are often more strik-
ingly fusiform than those of most Achlyw, as is well shown in Ward’s figures (783)
and in our Fig. 82. The apiculate odgonia which contain, when young, a very
opaque, dark-colored protoplasm, and, when old, a few large odspores, are very char-
acteristic and easily recognized. The odspores are surpassed in size and opacity

WiTH NOTES ON OTHER SPECIES. 121

only by those of A. megasperma, and may reach, in extreme cases, a diameter of
rather more than 40,. I have not observed the tendency towards the excentric type
of odspore said by DeBary to be sometimes shown by this species in the one-sided

position: of the oil-globule.
This plant shows some striking affinities with A. megasperma and A. polyandra ;
and, while in some respects intermediate between them, seems to take the position

here given it with less violence to all considerations.

ACHLYA OBLONGATA DeBary (’88).

Tl. : DeBary, ’88, Pl. X, Figs. 7-9.
Pl. XIX, Figs. 87-89.

Hyphe stout. Zodsporangia slightly fusiform, not abundant. Odgonial branches
short or rarely somewhat elongate, straight, racemosely arranged. Odgonia occasion-
ally intercalary, usually terminal, and elliptical, ovate, or obovate, rarely globular,
with smooth, unpitted walls. Antheridial branches slender, of strictly diclinous
origin, sometimes branched. Antheridia on every odgonium, numerous and small,
short-clavate. Odspores from one to twenty, usually seven to nine, in an odgonium,

centric, their average diameter about 27».

Massachusetts—Amherst: Louisiana—St. Martinville and Bayou Tortue,
Langlois. Europe.

The elongate odgonia and diclinous hyphe readily separate this type from all
other Achlye, no other diclinous species being known except A. prolifera. It has
occurred in cultures from Mill river, in Amherst, and from the aquatic room of the
Plant-house of the Massachusetts Agricultural College, as well as in two cultures
from Louisiana. The odgonia, which are typically rounded at their apices, show a
tendency to a pointed form in some Louisiana specimens (Fig. 88); while in all cul-
tures some of them are of a distinctly globular form, especially such as terminate
principal hyphe.

The odspores commonly do not occupy the whole interior of the ojgonium, but
are collected into a group at one side, leaving an empty space. I do not, however,
find them “ viel kleiner als die aller Verwandten,” as they are said by DeBary (’88)
to be.

In the form and size of its antheridia and the delicacy of its antheridial branches
as well as in its strict dicliny, the species strongly recalls S. diclina, but the resem-

blance goes no further.

122 THE SAPROLEGNIACEZ OF THE UNITED STATES,

Var. GLOBOSA var. nov.
Ill. Pl. XIX, Figs. 90, 91.

Odgonia] branches very short; odgonia globular; odspores reaching twenty-five

in number, averaging ten to fifteen; otherwise as in the type.

Pennsylvania—Philadelphia, Keller: Alabama—Auburn, Atkinson.

While not sufficiently different to be considered specifically distinct, this is cer-
tainly a well-defined variety of A. oblongata, marked by the very constant distinctions
above indicated. It has been received from two widely separated localities, and
appears to remain constant in culture. The odgonia are commonly larger than in the
type and the space unoccupied by spores is much more marked (Fig. 90), sometimes
amounting to more than half of the cavity. The antheridia correspond completely
with those of the type, and furnish the best grounds for regarding the differences as
of only varietal value.

This species shows no marked affinity with any other single species of Achlya,
and its insertion at any particular point in the series is comparatively arbitrary. No
real indication of affinities is possible in a linear arrangement of these species.

ACHLYA RACEMOSA Hildeb. (’67).

Syn.: A. lignicola Hildeb. (’67). Il].: Hildebrand, ’67, Pl. XV, Figs. 1-9, and XVI, 1-6a.
Cornu, ’72, Pl. I, Figs. 2-8.
Pl. XIX, Figs. 92-95.

Hyphe robust. Zodsporangia nearly cylindrical, sometimes tapering. Odgonial
branches racemosely arranged, short and straight. Odgonia globular, their walls
smooth and unpitted, somewhat irregularly thickened within, brownish-yellow when
old. Antheridial branches very short and simple, arising from the oégonial branches
near the basal walls of the odgonia, either above or below them. Antheridia one or
two, rarely three or four, to each odgonium, short-clavate, usually bent, and applied
by their apices to its wall. Odspores one to ten, commonly two to six, in an 06go-

nium, centric, their average diameter about 25,.

Massachusetts—Amherst. Europe.
The typical form of the species, which was studied by Hildebrand, has appeared
in two cultures in Amherst, one from dead leaves and slime from the outlet of a

WITH NOTES ON OTHER SPECIES. 123

spring, and the other from a few Ulothrichacee taken from an open cask sunk in the
soil of a pasture and apparently filled only by rains. It does not seem to be com-
mon. The species is readily recognized by the very characteristic antheridia, which
are quite unlike those of any other species. The color of the old odgonial wall and
its irregular thickening are also constant features. At the points of application of
the antheridia hardly any secondary thickening occurs, so that it remains thin there.

There can be no doubt that Hildebrand’s A. lagnicola is merely a depauperate
form of the present species, probably due in part to its growth on vegetable remains.
There seems to be no reason for giving it even varietal rank. But we may distin-
guish clearly the

Var. STELLIGERA Cornu (772).

Syn.: A. racemosa var. spinosa Cornu (772). Ill.: Hine, ’78, Pl. VI, Figs. 1-14.
A. colorata Pringsh. (’82). Pringsheim, ’74, Pl. XIX, Figs. 1-15; XXI, 1-3, 13;
and xox 1st

Pringsheim, ’82, Pl. XIV, Figs. 12, 15-81.
Pringsheim, ’83b, Pl. VII, Figs. 10-20.
Pl. XIX, Figs. 96-98.

Oégonial walls more or less abundantly producing short, rounded outgrowths,
more deeply colored when old. Odspores very rarely exceeding five in an odgonium.

Otherwise as in the type.

Massachusetts—Amherst and Northampton: New Jersey—Glassboro’, Keller :
New York—Ithaca, Mine: Louisiana—Bayou Tortue, Langlois. Europe.

This form seems much more abundant with us than the type. It was first
recorded as American by Hine (’78); for although it was not definitely identified by
him, his figures are unmistakable. I have observed it in cultures from three different
sources in Amherst and its vicinity, including a swamp pool, a fish hatchery, and a
river; also from a cedar swamp in New Jersey and from a Louisiana bayou.
Though the degree of development of the spines may vary considerably in different
specimens from the same culture, I have never seen a wholly smooth odgonium in a
culture of the spiny form, or a spiny one among those of the typical form. And it
is this fact which has seemed to indicate the propriety of characterizing the spiny
form as a distinct variety. The two spiny varieties named by Cornu (’72) are appar-
ently based on specimens with the spines respectively more and less developed ; and,
in the absence of evidence to the contrary, must be regarded as representing extremes

124 THE SAPROLEGNIACE# OF THE UNITED STATES,

of development within the limits of a single variety. The name STELLIGERA has
been chosen of the two used by Cornu, to avoid confusion with A. spinosa DeBary,
which is a very distinct species, in spite of the fact that it is quoted in Saccardo’s
Sylloge (’88) as a synonym of A. racemosa var. spinosa Cornu.

Besides the spiny odgonia and the fewer odspores, one observes that in this variety
the antheridial branches are, on the whole, even shorter than in the type-form, and
more frequently arise from the wall of the odgonium itself than in the latter.

In February, 1891, I received, through Dr. J. B. Paige, of the Massachusetts
Agricultural College, some trout eggs from the Northampton fish hatchery, which were
evidently attacked by a fungus of this family, and were dead. The hyphe failed to
develop sexual organs, but fresh cultures, obtained by throwing flies into the vessel
containing them, produced a new crop, bearing the sexual organs of this form. I was
unable to visit the hatchery, but am informed that it proves necessary to remove dead
eges very frequently, since the infection spreads rapidly, and all the eggs in the
hatching trays are killed unless this is done. After the eggs are hatched, the young
fry appear not to be injured by the fungus. If this be true, the present species would
seem to possess less parasitic capacity than the fungus of the salmon disease. It is
probable that, in case of the eggs, the fungus can attack only the non-living egg-
membranes, and that the death of the living cells of the egg is an indirect and not a
direct result of its attack.

This variety may represent a transitional form between some smooth and spiny
species of Achlya, not only as regards their ojgonial structure, but also in the reduc-

tion of the antheridial branches, which is carried even to their entire disappearance in

some spiny species.

Achlya oligacantha DeBary (88).

Til. : DeBary, ’88, Pl. X, Fig. 1.

The present species has delicate hyphz which bear globular odgonia with rather
few spines, and commonly four to eight odspores each. Antheridia are developed on
all the odgonia from rather elongate, simple branches of androgynous or diclinous
origin. It has been observed by DeBary in a single culture from Baden, but not yet
elsewhere. It may be regarded as representing a spiny form of the polyandra type,
and in this respect differs from the spiny species to be described, which do not
resemble closely any of the smooth-walled species, but constitute a distinct group of
forms.

WITH NOTES ON OTHER SPECIES. 125

ACHLYA PAPILLOSA sp. nov.
Iil.: Pl. XX, Figs. 99-102.

Hyphe rather slender, long. Zodsporangia sparingly developed, cylindrical,
little larger than the hyphe. Odgonia terminal on main threads or on short lateral
branches, or sometimes intercalary, oval or ovate, rarely globular, thickly studded
with short, blunt, wart-like outgrowths of their unpitted walls, often with a marked
apiculus. Antheridial branches usually developed with each oogonium, fine and branch-
ing, arising near it from the main thread, or rarely from the odgonial branch. Anther-
idia imperfectly formed. Odspores as many as twelve in an odgonium, oftenest four

to six, centric, their average diameter about 25).

Massachusetts—A mherst.

This plant, which seems to be sufficiently distinct from previously described spe-
cies, has been obtained in several cultures, but. from only a single source ; namely, the
very prolific mossy pool in Amherst, already mentioned. It may be recognized by its
long hyphe, finer than those of most Achlyc, and its odgonia with warty, rather than
spiny, walls, and several odspores in each. I have never seen well-differentiated
antheridia or fertilization-tubes, although the ends of the antheridial branches are |
applied to the odgonia.

While bearing no near resemblance to any species heretofore figured, this plant
may be somewhat closely related to the next, if the latter is well founded.

Achlya recurva Cornu (72).

_ So far as the incomplete account published by its author enables one to judge, this
is a distinct species from the last, and is separated by its longer and recurved odgonial
branches, on which the odgonia are usually borne laterally, and by its better
developed antheridia, often digitately branched. Aside from the original observations
of its author (’72), this species has been recognized only by Hartog (’88).

Achlya spinosa DeBary (’81).
Ill.: DeBary, ’81, Pl. IV, Figs. 13-18.

Its author’s latest description of this species (’88) does not fully agree with his
earlier figures (’81), especially in that he states that the odgonia are never intercalary,

126 THE SAPROLEGNIACEZ OF THE UNITED STATES,

while he has figured several such. It should be, however, readily enough recognized
by the usually barrel-shaped odgonia, with numerous blunt, and often broad or even
forked, outgrowths, each containing one or two odspores which often take an ellipti-
cal form corresponding to that of the cavity of the odgonium. The principal hyphz
commonly produce very abundant closely set, short, lateral branches that give to the
whole plant a densely woolly appearance ; and reproductive organs are often produced
only when these branches reach a new food-supply and give rise to fruiting hyphe.
The species was obtained by DeBary from a lake in the Black Forest, known as the
““'Titisee.”

ACHLYA CORNUTA Archer (’67).

Ill.: Archer, ’67, Pl. VI, Figs. 2-6.
Pl. XX, Figs. 108, 104.

Hyphe of medium size, short. Zodsporangia rare, cylindric. Odgonial branches
rarely long, straight or flexuous, racemosely arranged. Odgonia terminal, globular
or elliptical, densely beset with rather long, blunt outgrowths of their unpitted walls,
the apical one often larger and forming an evident apiculus. Antheridial branches
and antheridia wanting. Odspores from one to four in an odgonium, globular or

slightly flattened, centric, their average diameter about 29y.

Massachusetts—Amherst. Europe.

The same culture which yielded A. megasperma for the first time contained a
small amount, all I have seen, of this form. It has been referred with some doubt to
Archer’s species, since it fails to show at all a feature which one would suppose, from
that author’s account and figures, to be very characteristic of his plant; namely, the
development of several o6gonia in a series from a single hypha. In other respects,
however, it corresponds too closely with his description to justify one in regarding it
as distinct. Archer saw no sporangia, probably not, as he thought, because he found
it too late, but because of their rarity. In species which produce sporangia abund-
antly, one can always find empty ones on plants with mature odspores. In the limited
material at my disposal, I have been able to find but a single one, and that only long
after it was emptied. From below its base arose a branch bearing an odgonium.
This, so far as it goes, supports Archer’s conclusion that the plant is an Achlya,
which seems almost certainly correct. The odgonial branches sometimes show the
incurving mentioned by Archer, and are often less definitely bent. This writer states

WITH NOTES ON OTHER SPECIES. 197

that an odgonium may contain as many as eight or ten odspores; but I have never
seen more than four, and his figures show no more than three. He describes no special
antheridial branches, but says that the antheridia are like those of A. dioica Pringsh.
As these latter are not antheridia at all, one would expect to find, as is the case with
American specimens, that the species has no true male organs. As will be seen from
the figures, the spines could hardly be more closely set, and their form is more eylin-
drical than conical.

This and the next species seem to be closely related, the more so if the Ameri-
can form here described proves to be more typical than Archer’s.

Achlya stellata DeBary (’88).
Iil.: DeBary, ’88, P1.X, Figs. 10, 11.

Like the last, to which, indeed, it seems almost too similar, this plant has no
antheridia. Its globular or elliptical odgonia are covered by rather less numerous
spines that are shorter and sharper, therefore more conical, than those of A. cornuta.
The odspores are always single and sometimes correspond in form with the cavity of |
the odgonium, instead of being always globular. It is known only from a single
locality near Gottingen.

SPECIES INQUIREND®.

Achlya contorta Cornu (?72, Pl. I, Figs. 9-15), with smooth odgonia, containing on
an average eight odspores, and borne on long, spirally twisted branches with peculiar
local swellings, and with branched cylindrical antheridia; and <Achlya lewcosperma
Cornu (’%2), with antheridia similar to the last, and odgonia with two-pitted walls
and light-colored odspores, have been studied only by their author, whose descrip-
tions are too imperfect to determine their position. While they may prove to be
distinct species, more definite and complete information concerning them is much
needed.

Achlya dioica Pringsh. (60, Pl. XXIII, Figs. 1-5), should be written as a
synonym, probably of some species already described; but as the oédgonia were not
mentioned or figured, it is impossible to say to what species it belongs. The name
was given to some hyphe said by the author to be those of an Achlya, which were
attacked by a Chytridiaceous parasite, probably that since described by Cornu (’72)

A. P. 8.— VOL. XVII. Q.

128 THE SAPROLEGNIACE® OF THE UNITED STATES,

as Woronina. The cysts of the parasite were supposed to be the antheridia of the
fungus. This belief, which also led to the similarly erroneous application of the
name Saprolegnia dioica, was based on the supposed necessity for the existence of
antheridia and a sexual process in these plants.

Achlya Nowickii Racib. (Przyrodnik [The Naturalist] V, 327; 1884) may be
a good species, but I have not been able to examine the original description.

Achlya penetrans Duncan (Proc. Roy. Soc. London, XXV, 238; 1876) is
probably a boring Siphonaceous alga.

Aphanomyces DeBary (’60).

Hyphe very slender and delicate, little branched, forming a nebulous film over
the substratum. Zotdsporangia formed from their unswollen ends, often a hundred or
more times as long as broad; secondary ones not abundant, formed by cymose
branching. Zodspores cylindric-fusiform, cilia not yet observed, formed ina single
file in the sporangium, and escaping slowly by a terminal mouth which is formed with-
out the preliminary development of an oral papilla; immediately becoming encysted
and aggregated into a hollow rounded group; after resting, swarming in the laterally
biciliate form; finally encysting again and germinating. Odgonia usually terminal
and one-spored. Antheridia commonly present.

Key to established species.

a. Parasitic:on Zygnemacee ;sO0gonia SPiN Vic ere ecnisteise eolsieteielelerekelets ieee leita teeter et Aph. phycophilus.
Baprophytic. i. oo cicec vice ce ahs oie c ov \s,cacisve aiavelsieleietelsidloler cletsietelelare eval ateierelelein atete va telaic afaie 6) ats ie erate teleeic eet een db.
b. Obgonia quite smooth ; antheridia always present .........--.ececsscereeee cree nseccceeecceceeces APH, LEVIS.
Obgonia roughened or Spiny ’s «ais «is)sip sjejaisjo.n'» aivieyn eee wine. ose ce ee 6/dieletsieleialeteiniels eines eaiee Geree ae Eee ee eee C.
c. Spines large and prominent; antheridia always present .......c.ccceesssseccccccccccseccceceess Aph. stellatus.
Spines small or reduced to mere roughnesses; antheridia OLE AbSeNE. cecil s cccccw uss cece uene ce PH. NOARERS

APHANOMYCES L&vIs DeBary (’60).

Ill.: DeBary, ’60, Pl. XX, Figs. 17, 18.
Pl. XX, Figs. 105-107.

Zovsporangia very long and slender. Odgonia terminal on short lateral branches,

globular, with entirely smooth walls. Antheridia abundantly developed on all

WITH NOTES ON OTHER SPECIES. 129

odgonia, large, clavate-cylindric, on short branches of androgynous or diclinous origin,
sometimes even from the odgonial branch. Odspores single, globular, centric, 20 to 22,,

in diameter.

Massachusetts—Amherst. Europe.

The present species appeared in a single culture from moss and Alge (chiefly
Tolypothrix) from the mossy pool frequently mentioned, which had stood in a jar in
the laboratory for several months. It is readily distinguished by its smooth odgonia
from all other species except the smoothest forms of Aph. scaber, from which it differs
in its large and numerous antheridia and larger odspores. ‘The fertilization tubes are
plainly developed and the species seems in all respects to represent the most primi-
tive form of the genus.

It is worthy of remark that, although the genus was described more than thirty
years ago, no other species than the four then characterized have yet been recognized.

Aphanomyces stellatus DeBary (’60).

Il].: DeBary, ’60, Pl. XIX, Figs. 1-13.
Sorokine, *76, P). VII.

Distinctly marked by its odgonia with large, blunt spines or warts, and its well-
developed antheridia, which seem to be present on every odgonium, combined
with its strictly saprophytic habit. DeBary states that in rare cases an oégonium
may contain two odspores, the only deviation from the one-spored condition known
to occur in the genus.

This species has been studied by Sorokine (’76), as well as by its author, and is
probably common in Europe, and perhaps also in America, though I have not yet
met with it. It seems to be similar to the last species except in the spiny character
of its odgonia, a condition towards which, whatever its significance, there is a distinct
tendency in several groups of species in this family.

Aphanomyces phycophilus DeBary (’60).
Ill.: DeBary, ’60, Pl. XX, Figs. 19-24.

Although the zodsporangia and sexual organs were not observed by DeBary on
the same plant, there seems to be little doubt that this species is properly placed

130 THE SAPROLEGNIACEZ OF THE UNITED STATES,

in the present genus. Its odgonia are the largest of the genus and have rela-
tively smaller and sharper spines than the last species, while its antheridia are
well developed and always present. But its chief peculiarity lies in its parasi-
tism upon Alge, in which it is unique among Saprolegniacee and recalls the
related genus Pythium. Its host-plants are Sporogyra and Zygnema, whose cells
it rapidly destroys. It has been observed as yet only in Europe. While struc-
turally distinct from the last species, and shown by DeBary to be also physio-
logically so, this must be regarded as a plant of the same type, which has
acquired the parasitic habit.

APHANOMYCES SCABER DeBary (60).

Ill. : DeBary, ’60, Pl. XX, Figs. 14-16.
DeBary, ’81, Pl. VI, Figs. 30-36.
Pl. XX, Figs. 108-111.

Zoosporangia very long. Odgonia small, terminal on short branches, or on main
hyphe, globular; their walls with numerous short spines or prominences, or merely
irregularly roughened. Antheridia on branches of androgynous or diclinous origin,

small, not on all odgonia. Odspores single, globular, centric, 16 to 18, in diameter.

Massachusetts—Amherst. Europe.

The spiny form of this species (Figs. 108, 109) appeared in a single culture from
dead leaves and slime taken from a ditch in Amherst, and the merely rough form
(Figs. 110, 111) was obtained later from a mass of Spirogyra which grew in the same
ditch, at a point a few rods away from the source of the first.

Both forms agree closely except in the roughnesses of the odgonia, which
may be very slight or may take the form of short and rather sharp spines. But the
species is always known by the smaller odspores and by the reduced size and number
of the antheridia. These latter are wholly wanting on half or even more of the
odgonia. In my few cultures they have been rather less abundant in the smoother
than in the spiny form, and the two extreme types of odgonia have not appeared
together. It may therefore prove justifiable to regard the smoother form as a distinct
variety, but further evidence is needed on this point. The character of the present spe-
cies points to the conclusion that it should be regarded as the least typical of the
genus, representing a degeneration in both sexual organs from the type of 4. stellatus.

WITH NOTES ON OTHER SPECIES. 131
_Thraustotheca* gen. nov.

Hyphe stout, branching. Zodsporangia formed from their swollen ends, clavate ;
the later ones formed by sympodial branching. Zodspores encysting within the spo-
rangium at once after their formation, somewhat polyhedral from pressure, but with
distinct membranes; soon set free by the breaking up of the very fragile sporangial
wall, and then escaping from their cysts to swarm in the laterally biciliate form ;
finally encysting again and germinating. Odgonia several spored, with abundant
antheridia.

Thraustotheca clavata (DeBary).
Syn.: Dictyuchus clavatus DeBary (’88). Ill.: Biisgen, ’82, Pl. XII, Figs. 1-8.
DeBary, ’88, Pl. IX, Fig. 3.

This, the only species of the genus yet known, strikingly resembles Achlya
DeBaryana in its sexual organs, having similar long and branching antheridial threads
and smooth odgonia with excentric odspores. But its short, clavate sporangia and
the peculiarities in the development of its zodspores separate it widely from the latter.
It is known only from near Strassburg, Germany.

A careful comparison of the characters of this species, as drawn from the accounts
of Biisgen (’82) and DeBary (’88), with those of species of Dictyuchus, taken from
the American specimens studied by the writer, will furnish, it is believed, sufficient
justification for its separation from the latter genus. An account of the differences
on which the new genus is based will also be found in the discussion of generic rela-
tionships on a previous page. The close analogy of the sporangia of this plant with
those of Mucor has already been pointed out by Solms-Laubach, to whom we owe
the arrangement of incomplete fragments of DeBary’s last paper (’88), and he has
also hinted at the possibility of generic differences between this and the other
described species of Dictyuchus. His suspicions are quite supported by the very differ-
ent means adopted, in the two types, for the release of the zoéspores after their encyst-
ment within the sporangium. The species needs further study, especially with refer-
ence to the nature of the intermediate substance said to exist between the zodspores
within the sporangium.

Dictyuchus Leitgeb (68).

Hyphz stout or slender, branching. Zodsporangia formed from their swollen
ends, usually fusiform; the later ones formed in basipetal succession below the earlier,

* @pavortds, fragile ; A777, a case.

132 THE SAPROLEGNIACEZ OF THE UNITED STATES,

or by sympodial branching, or in both ways on the same hypha. Zodspores encysting
within the sporangium at once after their formation, polyhedral from mutual pressure,
the membrane of each face united with that with which it is in contact to form an
apparently single wall; after a time escaping, each by a separate opening through
the outer wall, and swarming in the laterally biciliate form; finally encysting again
and germinating. Odgonia terminal or intercalary, one- or several-spored. Anthe-
ridia usually present. E Lame

Key to the known Species.

@. Plants diclinous’; oGspores| single sisjciscte c= /<14=\</clocs 02 aca ore lciole elcicte <ivieieietoterciole elie teetar= tstel=rsioteloraiaie sac ieee aie db.
Plants androgynous ; odgonia several-spored........-+-ee++-- GORDO daedod Sos oa cOOS coaIODOobeSOr D. polysporus.
b. Odgonia under 30, in diameter, encircled by the antheridia...................-.- set eeeee seen ees D. monosporus.
Odgonia over 30y in diameter, not encircled by the antheridia............eeeeseeeceeceseceeeeeees D. Maenusi.

Dictyucnus Maenusit Lindst. (’72).

ll.: Lindstedt, °72, Pl. I, Figs. 1-15.
Pl. XX. Figs, 112-114.
Hyphe rather large. Zovdsporangia cylindric or fusiform. Odgonia terminal on
slender branches, globular, smooth-walled, unpitted. Antheridia cylindric or slightly
clavate, on all ojgonia, borne on slender branches of diclinous origin. Odspores

single, centric, about 25, in diameter.

Massachusetts —Cambridge, Trelease. Hurope.

Our knowledge of the occurrence of this species in America rests on the notes
and preparations of Prof. Trelease, who obtained it in 1881 from water in the
Botanic Garden, at Cambridge. It can be confounded only with D. monosporus,
from which it differs in its somewhat larger odgonia and less coiled antheridial
branches.

Lindstedt states that it is only in this species that the sporangia are formed from
the hyphe in basipetal succession, but it seems doubtful if this is strictly true, in
view of certain observations to be mentioned later.

The definition of the present genus by its author was less restricted than that
above adopted, which is essentially that-of Lindstedt (72), but seems, for reasons
suggested in the discussion of the genus Thraustotheca, to be a more accurate and

philosophical one.

WITH NOTES ON OTHER SPECIES. 133
Dictyuchus monosporus Leitgeb (’69).
Ill.: Leitgeb, 69, Pl. XXII, Figs. 1-12; XXIII, 1-8.

Not yet known in America. Resembles the last species closely, but has smaller
odgonia and short, coiled antheridial branches.

Dictyuchus polysporus Lindst. (’72).
Til.: Lindstedt, ’72, Pl. II, Figs. 1-3 ; III, 1-7.

Distinguished by its large, globular, many-spored odgonia and its antheridial
branches of androgynous origin, from all other described species of the genus. Not
seen in America.

In one of my cultures of Aph. scaber there appeared hyphz and sporangia of a
species of Dictyuchus. A vigorous growth of it was readily obtained on fresh flies
and kept up in successive generations for several months. In ordinary cultures in
glass vessels, the sporangia are freely and normally produced both in basipetal series
and by cymose branching. In cultures on slides in a moist chamber, one often sees
sporangia lobed and forked in quite irregular fashion, like those figured by Leitgeb —
(69) for D. monosporus. The plant seems slenderer and more delicate than
D. Magnusu of Prof. Trelease’s preparation, and is very probably not that species.
It does not appear that either the basipetal development of sporangia or their forked
shape can be regarded as of any specific value. In spite of repeated efforts to induce
their development, the sexual organs of this plant have uniformly failed to appear,
so that it is quite impossible to say what species it represents. After the formation
of sporangia has begun to: decline, the main hyphz of a plant commonly send out
a mass of fine lateral branches, themselves much branched and interlacing, which
give to the whole culture a densely woolly appearance. These threads probably
correspond to those which bear, the sexual organs in D. monosporus, but, although
readily kept alive and healthy for a long time, they remain persistently sterile.
Gradually the later generations of the plant showed signs of degeneracy, and ulti-
mately refused to yield normal plants.

Two or three cultures from various sources have produced a plant with slender
hyphe and sporangia of the Dzactyuchus type, except that they contain only a single
file of zodspores, being cylindrical and little larger than the hyphe. It is this form
whose sporangium is shown in Fig. 16. I have never been able to find its sexual
organs, and specific determination is, therefore, impossible.

134 THE SAPROLEGNIACE# OF THE UNITED STATES,

Aplanes DeBary (’88).

This genus represents the extreme result of the reductional tendencies observed
in previous genera, in that both swarming stages are entirely suppressed. The zo0-
spores encyst within the sporangium and germinate there, producing germ-tubes
which penetrate the sporangial wall and thus make their way into the surrounding
water. : A

Aplanes androgynus (Archer ).

Syn.: Saprolegnia androgyna Archer (’67). Tll.:-Archer, ’67, Pl. VI, Fig. 1.
Achlya Braunit Reinsch (78). Reinsch, ’78, P1. XIV, Figs. 1-6.
Aplanes Braunii DeBary (’88). DeBary, ’88, Pl. IX, Fig. 2.

The present very striking species would seem not to be rare in Europe, having
apparently been met with by several investigators; but it is not known to be Ameri-
can. It is recognized by its several spored, barrel-shaped or spindle-shaped odgonia,
with pitted walls, often formed in series from a hypha, and by its numerous antheri-
dial branches arising just below the basal wall of each odgonium, even though it be
from the sides of the next odgonium in the series.

Although it is not absolutely certain that the plants studied by Archer, Reinsch,
and DeBary all belonged to the same species, there seems to be little doubt of the
correctness of such a conclusion, in spite of the fact that Reinsch’s account of the
sporangia does not agree with DeBary’s, and that Archer does not mention the pits
of the odgonial wall. The overlooking of the latter would have been less remarkable
twenty-five years ago than to-day; and Archer’s failure to see the sporangia is
readily explained by DeBary’s statement that they are very rarely developed.
Archer’s arguments for placing his plant in the genus Saprolegnia are drawn wholly
from analogy, and not from observation of the sporangia.

Reinsch’s description of the sporangia suggests that he perhaps did not see those
of the plant whose sexual organs he studied, but mistook for them those of a Dictyu-
chus which may have grown intermingled with the other. At all events, the agree-
ment in the structure of the sexual organs has led DeBary to feel very sure of the
identity of his plant with Reinsch’s, but he seems to have overlooked the equally
complete similarity of Archer’s plant. It seems best, then, to consider all the names
above quoted as synonyms ; and, while retaining DeBary’s generic name, the plant
must bear the specific designation given it by Archer, since that is the older.

WITH NOTES ON OTHER SPECIES. 135

Subfamily Leptomitec.

Leptomitus Agardh (24).
Syn.: Apodya Cornu (’72).

Hyphe stout at the base, marked off at intervals by deep constrictions into dis-
tinct segments; branching abundant, dichotomous below, but often monopodial on
the finer ultimate divisions; -branches arising only from the acroscopic ends of the
segments. Zovdsporangia formed from swollen segments of the hyphz which are cut
off at the constrictions ; the primary ones from apical segments, and later ones often
several in basipetal succession. Zodspores biciliate, monoplanetic (?), swarming
separately: Odgonia and antheridia unknown.

Lrrtromitus LactTeus (Roth) Ag. (24).

Syn.: Conferva lactea Roth (1789). Ill.: Dillwyn, ’09, Pl.
Saprolegnia lactea Pringsh. (60). Pringsheim, ’60, Pl. XXIII, Figs. 6-10; XXV, 1-6.
Apodya lactea Cornu (’72). Pringsheim, ’83b, Pl. VII, Figs. 1-9.

Exsic.: Rabh., Algen Sachsens, 587. Biisgen, ’82, Pl. XII, Figs. 9-15.

Pl. XX, Figs. 115-118.

Hyphe rapidly decreasing in diameter with successive subdivisions; apical seg-
ments about 16, in diameter and often forty times as long. Zodsporangia cylindri-
eal, from slightly swollen segments, their mouths terminal or lateral. Zodspores in

a single file within them.

Massachusetts—Amherst: Connecticut—Bridgeport, Holden. Europe. Prob-
ably common everywhere.

This unmistakable form appears to be common enough in Amherst, and is un-
doubtedly so elsewhere in favorable situations. It prefers, as has been before inti-
mated, waters which are somewhat, but not too strongly, polluted by organic
substances. I first met with it on masses of decaying Algze which had died and
broken down in the vessel in which they had been kept. Afterwards it appeared in
fly cultures from waters from the outlets of drains, containing decaying vegetable
matter. It does not appear to flourish where active decay of animal substances is
going on. In favorable places, it often forms very dense masses of closely felted
threads, covering very large surfaces. Gceppert observed (’52) such a case in a
small stream below a beet-molasses manufactory, near Schweidnitz, in Silesia. I

A. P. S.—VOL. XVII. R.

—

136 THE SAPROLEGNIACEZ OF THE UNITED STATES,

have received from the herbarium of Prof. W. G. Farlow a specimen from a similar
mass, collected in a stream, below a “tripe-house,” at Bridgeport, Conn., by Mr.
Isaac Holden.

The species is easily recognized by the regularly dichotomous branching and
rapid reduction in size of its principal hyphz, and by its cylindrical sporangia
developed in basipetal succession. While the zodspores ordinarily esvape from the
sporangia, they sometimes become encysted within them (Fig. 117). . It is this fact,
probably, which led Braun to state (51) that the spores of Leptomitus are arranged
in a row in the spore cases, and that “no active gonidia seem to occur.”

The hyphe of this plant are especially favorable for the study of the so-called
cellulin grains. Frequently, when a sporangium is formed, its narrow connection
with the next segment is closed by the occupation of the passage by one of these
granules. This simple method of forming a cross partition is perhaps not very differ-
ent in kind from that which occurs in the Saprolegniee.

SPECIES INQUIRENDA AUT EXCLUDEND 4.

Many so-called species of this genus have been described by early authors, and
may be found catalogued by Kiitzing (49), and in part by Saceardo (88). The
great body of them are merely sterile, submerged hyphe of uncertain origin, and even
to list them here would be useless. The only species which need be mentioned, and
concerning which further information is desirable, are:

Leptomitus Libertie (Bory) Ag. (24) [Exsic., Libert, Plantes Crypt. Ard., 97],
placed doubtfully by Saccardo (’88) under Saprolegnia. The published description
mentions no reproductive organs and I have not been able to examine J.ibert’s exsic-
cata. So far as the description goes, the plant may belong to this family, but probably
rather to the Saprolegniew than to the present subfamily.

Leptomitus rubescens DeBréb. [ Exsic., Algues de la France, 306], and

Leptomitus Dorie Ces. | Exsic., Rabh., Algen Sachsens, 575] are mentioned only
in the quoted eaxsiccate. They will probably prove to be only sterile hyphe.

Apodachlya Pringsh. (’83b).

Hyphe slender throughout, marked off at intervals by constrictions into distinct
segments ; branching monopodial; branches arising from any part of a segment.

WITH NOTES ON OTHER SPECIES. 137

Zoosporangia from considerably swollen segments, renewed by sympodial branching.
Zodspores usually becoming grouped at the mouth of the sporangium, on escaping,
rarely swarming separately ; soon leaving their cysts and swarming ; finally encysting
again and germinating. Sexual organs known in’but one species.

As Pringsheim has observed in one species (’83b), and Zopf in another (’88), that
the zodspores commonly escape after the manner of Achlya, there seems to be as good
reason for the generic separation of the following species from Leptomitus, as for
keeping Saprolegnia and -Achlya distinct, and also since there are marked differences
in the branching of the hyphee and in the formation of secondary sporangia.

The species heretofore recognized are :

Apododachlya brachynema (Hildeb.) Pringsh. (’83b).
Syn.: Leptomitus brachynema Hildeb. (67). Ill.: Hildebrand, ’67, Pl. XVI, Figs. 12-23.

Has hyphz with short segments, and globular sporangia opening by short necks
and often occurring in series. No sexual organs are known.

Apodachlya pyrifera Zopf (88).
Ill: Zopf, 88, Pl. XXI, Figs. 1-21.
Has hyphe with long segments, pyriform sporangia, developed singly and each

opening by a distinct papilla, and large globular chlamydospores. Sexual organs
have not been seen.

To these species it seems necessary to add:

APODACHLYA (?) COMPLETA Sp. nov.

Ill.: Pl. XX, Figs. 119-121.

Hyphe slender, with rather long segments. Ziosporangia unknown. Odgonia
terminal on branches of one or a few segments, each representing a swollen segment,
globular, with smooth, unpitted walls. Antheridia formed from lateral cylindrical
branches of one or two segments which arise from the slightly swollen apical part of
the segment next below the odgonium, usually two from each. Odspores oftenest five
to seven, sometimes less or more, thick-walled when mature, centric, 18 to 20, in
diameter.

138 THE SAPROLEGNIACE OF THE UNITED STATES,

Louisiana—St. Martinville, Langlois.

This very interesting plant affords the first recorded instance of the occurrence
of sexual organs among the Leptomitee, unlessthe imperfectly described S. (Leptomitus)
corcagiensis of Hartog be such an example. The latter cannot, however, be the same
form as the present one. This plant appeared in very limited quantity on a fly which
had been thrown into an old and feeble culture of Saprolegnia sp., obtained by
Rey. Mr. Langlois from a ditch in St. Martinville, La. The moribund condition of
the culture when it was received caused these freshly added flies to decay so much
that the development of other Saprolegniew was slight and unhealthy; but the few
plants of this form were developed normally and seemed to find their surroundings
congenial, indicating that it, like Z. lacteus, is partial to polluted waters.

A very careful and detailed, examination of the material failed to discover any
sporangia, and it does not, therefore, certainly belong to the present genus. But,
since the hyphe are certainly not those of Z. lacteus, but are slender throughout,
branch monopodially from all parts of their rather long segments, and in general
resemble strikingly those of Apod. pyrifera, it is placed provisionally here.

Its great interest lies, as before suggested, in its possession of well-formed
sexual organs of peculiar and characteristic structure. The odgonia are globular and
are formed by the swelling of the terminal segment of a branch. When young, they are
filled by granular protoplasm which is entirely used up in the formation of the
odspheres, a fact which confirms our previous belief that these plants belong to the
present family. The narrow connection between the odgonium and the next segment
below it becomes quite solid, and the apical end of the latter segment is usually
somewhat swollen and gives rise to the, commonly two, antheridial branches. The
odspores, when mature, are quite thick-walled and of uniform and moderately granu-
lar appearance (Fig. 120).

The antheridial branches are composed of one or two cylindrical segments each,
and are at first uniformly filled with protoplasm and applied to the ojgonium (Fig.
119). Later, a part of a segment may be cut off by a transverse wall (Fig. 120),
and then apparently constitutes an antheridium. The part cut off in Fig. 120 will be
seen to be quite empty, and similar cases are frequent; but I have never been able to
recognize fertilization tubes homologous with those of the Saprolegniee. On the
other hand, the whole segment may become nearly or quite emptied, as shown in the
right hand branch in Fig. 121. The left hand branch in the same figure shows a
condition observed in a number of instances, which is one of much interest. The
limited material at hand did not permit extended observations as to its significance,
but the facts appeared to be as follows in all of the several similar specimens ob-

WITH NOTES ON OTHER SPECIES. 139

served. In the basal part of the branch there are formed, in a single row, several
globular protoplasmic masses with distinct walls. The spaces around the individual
spheres seem to be separated by faint false walls of protoplasmic substance, proba-
bly formed from the protoplasm of the segment. These spheres produce structures
which can be compared to nothing but germ tubes in their appearacne and growth;
and i have seen them in all stages from the beginning of their formation to the length
shown in Fig. 121. They ordinarily grow towards the odgonium, but I have scen
two of them, developed from two spheres contained in the same segment, directed
away from it. In this last case they were in the lower segment of a branch of two
segments whose upper member showed the same condition as that drawn in Fig. 120.
While one’s first inclination may be to regard these peculiar structures as specialized
male cells which produce fertilization tubes of a different type from those of the
Saprolegniec, yet the emptying of the apical parts of some branches, even of the
same ones that contain the spheres, and the fact of the growth of their tubes away
from the odgonium in one observed case, make it quite as probable that they are para-
sites in the antheridial branches. Yet if they are parasites, it is remarkable that they
should not have been seen in other parts of the plant. JI have not been able to
observe what follows the contact of their tubes with the oogonium, not having seen ~
them late enough in their history.

The general incompleteness of these observations, which bring up many interest-
ing possibilities, can justify nothing more than the suggestion of some of these
possibilities. The emptying of the separated apical parts of some branches without
any evident formation of fertilization tubes needs further investigation; it is not
impossible that this species may be shown to differ from the Saprolegniew which have
been studied, in the oceurrence of a truly sexual process. It is greatly to be hoped
that some one may soon have the opportunity of studying abundant material of this
plant.

140 THE SAPROLEGNIACEZ OF THE UNITED STATES,

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WITH NOTES ON OTHER SPECIES. 141

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GRUITHUISEN, F. v. P., ’21: Die Branchienschnecke und eine aus ihren Ueberresten hervorwachsende lebendig
gebahrende Conferve. Nova Acta Acad. C. L. C. N. C., Bd. X, Th. II, p. 487; m. T. XX XVIII: 1821.

* HANNOVER, A., 7389: Miiller’s Archiv fiir Anat. und Physiol., 1839, p. 339.

—— ’42: Fernere Erlauterung der contagiosen Confervenbildung auf Froschen und Wassersalamandern. Miiller’s
Archiv fiir Anat. u. Phys., 1842, p. 73; m. T. VII.

Hartoe, M. M., ’87: On the Formation and Liberation of the Zodspores of the Saprolegniee. Quart. Journ. Mic.
Science, Vol. XXVII, N. S., p. 427: 1887.

— ’88: Recent Researches on the Saprolegniee. Annals of Botany, Vol. II, No. VI, p. 201: 1888.

— ’89: Recherches sur la structure des Saprolegniées. Comptes Rendus, T. 108, p. 687: 1 Apr. 1889.

— ’89a: Technique applicable 4 l’étude des Saprolegniées. Bull. Soc. Bot. de France, T. XXXYI, II, p. CCVIII ;
Actes du Congres de Bot.: 1889.

—— ’92: Some Problems of Reproduction, etc. Quart. Journ. Mic. Science, Vol. XX XIII, N.S., p. 1: 1892.

HILDEBRAND, F., ’67: Mycologische Beitrage. I. Jahrb. fiir wiss. Bot., Bd. VI, p. 249; m. T. XV-XVI: 1867.
Also, Ann. Sci. Nat., 5e Sér., T. VIII, p. 314, Pl. 18, 19.

+HIne, F. B., ’78 : Observations on Several Forms of Saprolegniex. Amer. Quart. Mic. Journal, Vol. I, Nos. 1 and
2, pp. 18 and 136; with Pl. [LV-VIL: Oct. 1878 and Jan. 1879.

Horrmann, H., ’67: Ueber Saprolegnia und Mucor. Bot. Zeitung, Bd. XXV, p. 345 u. 353; m. T. VIIL: 1867.

{Humpurey, J. E., ’91: Notes on Technique. II. Bot. Gazette, Vol. XVI, p. 71: March, 1891.

Huxey, T. H., ’82: Saprolegnia in Relation to Salmon Disease. Quart. Journ. Mic. Science, Vol. XXII, N. S.,
p. 811 ; with woodcut : 1882. ‘

Karsten, H., 69: Chemismus der Pflanzenzelle. 1869. (See p. 75.)

Kouetzine, F. T., ’43: Phycologia Generalis. Lipsix, 1843.

—— ’49: Species Algarum. Lipsix, 1849.

*LEDERMUELLER, 1760: Microscopische Augen- und Gemiiths-Ergétzungen. 1760.

{Lzrpy, J., 50: Entophyta in Bodies of Animals. Proc. Acad. Nat. Sci. Philadelphia, Vol. V, p. 7: 12 Feb. 1850.

Ler1Texs, H., ’68: Zwei neue Saprolegnieen. Bot. Zeitung, Bd. XXVI, p. 502 : 1868.

— ’69: Neue Saprolegnieen. Jahrb. fiir wiss. Botanik., Bd. VII, p. 357; m. T. XXII-XXIV: 1869.

LinpsteptT, K., ’72: Synopsis der Saprolegniaceen und Beobachtungen iiber einige Arten. Dissert. Berlin, 1872.

*Lyne@ByE, H. C., 19: Tentamen Hydrophytologiz Danice, etc. Havni, 1819.

Meyen, F. J. F., 31: Zur Erlatiterung des Vorhergehenden. (Appended to Nees v. Esenbeck, ’31, g. v.)

—— ’3): Hinige nachtragliche Bemerkungen iiber die Pilzbildung auf den Leibern der aufgestorbenen Fliegen.
Wiegmann’s Archiv fiir Naturgesch., I. Jahrg., II, p. 354 : 1835. :

—— ’39: Von der Fortpflanzung der Pilze. Neues Syst. der Pflanzenphysiol., Bd. III, p. 453; T. X, Figs. 18, 19:
1839.

t As the manuscript of the present memoir was completed before the appearance of this synopsis of the family, I have not been able to

refer to it.

142 THE SAPROLEGNIACEZ OF THE UNITED STATES,

MUELLER, C., ’83: Meine Stellung zur Frage von den Spermamoeben der Saprolegnieen. Bot. Centrabl., Bd. XV, p.
125 ; 1883. :

Murray, G., ’85: Inoculation of Fishes with Saprolegnia ferax. Journal of Botany, Vol. XXIII, p. 302: 1885.

* NAEGELI, C., ’47: Zeitschrift fiir wiss. Botanik, 1847, Hefte 1, 3 u. 4.

NEES VON ESENBECE, C. G., ’23: Zusatz. (Appended to Carus, ’23, g. v., p. 507.)

—— ’31: Mittheilungen aus der Pflanzenwelt. “II. Confervenbildung aus todten Fliegenleibern. Nova Acta Acad.
C. L. C. N. C., Bd. XV, Th. II, p. 361: 1881.

PFEFFER, W., ’84; Locomotorische Richtungsbewegungen durch chemische Reize. Unters. aus d. Bot. Inst. zu
Tiibingen, Bd. I, Heft III, p. 393 : 1884.

PrinesHErm, N., 51: Entwickelungsgeschichte der Achlya prolifera. Nova Acta Acad. C. L.C. N.C., Bd. XXIII,
Heft I, p. 395; m. T. XLVI-L: 1851.

—— ’55: Ueber die Befruchtung der Algen. Monatsber. der Akad. der Wissensch. zu Berlin, 1855, p. 133. Also, in
Ann. Sci. Nat., 4¢ Sér., T. III, p. 378.

— ’57: Beitiige zur Morphologie und Systematik der Algen. II. Die Saprolegnieen. Jahrb. fir wiss. Botanik,
Bd. I, p. 284; m. T. XTX-XXI: 1857. Also, in Ann. Sci. Nat., 4¢ Sér., T. XI, p. 349.

— ’60: Beitrage zur Morphologie und Systematik der Algen. IV. Nachtrage zur Morphologie der Saprolegnieen.
Jahrb. fiir wiss. Botanik, Ba. II, p. 205 ; m. T. XXII-XXYV: 1860.

—— ’74: Weitere Nachtrage zur Morphologie der Saprolegnieen. Jahrb. fiir wiss. Botanik, Bd. IX, p. 191; m. T.
XVII-XXII: 1874.

— ’82: Neue Beobachtungen iiber den Befruchtungsact von Achlya und Saprolegnia. Sitzungsber. der Akad. der
Wissensch. zu Berlin, 1882, p. 855 ; m. T. XIV.

—— ’83: Nachtragliche Bemerkungen zu dem Befruchtungsact von Achlya. Jahrb. fir wiss. Botanik, Bd. XLV, p.
111: 1883.

—— ’83a: Ueber die vermeintlichen Ameben inden Schlauchen und Odgonien der Saprolegnieen. Bot. Centralblatt,
Bd. XIV, p. 878: 1883.

— ’83b : Ueber Cellulinkérner, eine Modification der Cellulose in Kérnerform. Ber. der Deutschen Bot.
Gesellsch., Bd. I, p. 288; m. T. VII: 1883.

REINEE, J., "69: Ueber dic Geschlechtsverhaltnisse von Saprolegnia monoica. Archiv fiir micros. Anatomie von M.
Schultze, Bd. V, p. 183; m. T. XII: 1869.

Retnscu, P. F., "78: Beobachtungen iiber einige neue Saprolegniex, etc. Jahrb. fiir wiss. Botanik, Bd. XI, p. 283;
m. T. XIV-XVII: 1878.

Rosin, C., 53: Histoire naturelle des Végétaux parasites, etc. Paris, 1853.

*Rorn, A. W., 1789: Beytrage zur Botanik. 1789.

Rotuert, W., ’88: Die Entwickelung der Sporangien bei den Saprolegnieen. Cohn’s Beitrage zur Biologie der
Pflanzen, Bd. V, p.291; m. T. X: distrib. 1888. Also published in Polish in 1887.

RouMEGURRE, C., ’91: Fungi selecti exsiccati. Cent. LX: 1891.

Saccarpo, P. A., 88: Sylloge Fungorum, etc. Saprolegniacee by A. N. Berlese and J. B. DeToni. Vol. VII,
p. 265: Patavii, 1888.

— ’91: Sylloge Fungorum, ete. Supplementum Universale. Saprolegniacee. Vol. IX, Pars I, p. 345: Patavii,
1891.

ScHLEIDEN, M. J., ’43: Grundziige der Botanik. ite Aufl.: Leipzig, 1842-3. (See p. 264.) Also Eng. transl. by
Lankester : London, 1849.

Scumitz, F., ’79: Untersuchungen iiber die Zellkerne der Thallophyten. Verh. des naturhist. Vereins der Preuss.
Rhein]. und Westfulens, 4 Aug. 1879, p. 345.

*SCHNETZLER, J. B., ’87: Infection d’ une Larve de Grenouille par Saprolegnia ferax. Archives de Sciences Physi-
ques et Naturelles, Genéve, 8¢ pér., Vol. 18, p. 492: 1887.

*ScHRANK, F. von P., 1789: Baiersche Flora: Miinchen, 1789. (See Bd. 2, p. 553.)

ScHROETER, J., 69: Ueber Gonidienbildung bei Fadenpilzen. 46ter Jahresber. der Schles. Gesellsch. fiir vaterl.
Cultur, fiir das Jahr 1868, p. 133 : 1869.

WITH NOTES ON OTHER SPECIES. 143

ScHROETER, J., 86: Saprolegniacei. Die Pilze Schlesiens, Lief. II, III, p. 252-7. Breslau, 1886-7.

Smitu, W. G., ’78: The Salmon Disease. Gardener’s Chronicle, 4 May, 1878, p. 560; with three cuts. Also, in Gre-
villea, Vol. VI, p. 152.

Soroxrne, N., ’76: Quelques Mots sur le Developpement de l’Aphanomyces stellatus. Ann. Sci. Nat., Bot., 6¢ Sér.,
T. III, p. 46; avec Pl. 7: 1876.

*SPALLANZANI, 1777: Opuscules de physique. Genéve, 1777.

*Stiuuine, ’41: Miller’s Archiv fiir Anat. und Phys., 1841, p. 279; m. T. XI.

StTrrLine, A. B., 78: Notes on the Fungus Disease Affecting Salmon. Proc. Royal Soc. Edinburgh, Vol. IX, p. 726:
1 July, 1878.

-— 79: Additional Observations on the Fungus Disease Affecting Salmon and Other Fish. Proc. Royal Soc. Edin-
burgh, Vol. X, p. 232: 2 June, 1879.

— ’79a: Additional Observations on Fungus Disease of Salmon and Other Fish. Proc. Royal Soc. Edinburgh,
Vol. X, p. 870: 15 December, 1879.

STRASBURGER, E., ’80: Zellbildung und Zelltheilung IIIte Aufl. Jena, 1880.

THURET, G., 50: Recherches sur les Zoospores des Algues et les Antheridies des Cryptogames. Ann. Sci. Nat.,

Bot., 3e Sér., T. XIV, P. 214; avec Pl. 16-31: 1850.

Unesr, F., 43: Hiniges zur Lebensgeschichte der Achlya prolifera. Linnea, Bd. XVII, p. 127; m. T. TV : 1843.
Also, Ann. Sci. Nat., Bot., 8e Sér., T. II, p. 10.

WaceEr, H., ’89: Observations on the Structure of the Nucleiin Peronospora parasitica, and on their Behavior during
the Formation of the Odspore. Annals of Botany, Vol. IV, No. XIII, p. 127; with Pl. VI: 1889.

Watz, J., "70: Beitrage zur Kenntniss der Saprolegnieen. Bot. Zeitung, Bd. XXVIII, p. 587 und 553; m. T. IX:
1870.

— "70a: Ueber die Entleerung der Zodsporangien. Bot. Zeitung, Bd. XX VIL, p. 689 u. 703 : 1870.

WARD, H. M., ’83: Observations on Saprolegnize. Quart. Journ. Mic. Science, Vol. XXIII, N.8., p. 272; Pl. XXII:
1883.

* WRISBERG., 1765 : Observationes de animalculis infusoriis satura. Gé6ttingse, 1765.

Zop¥r, W., Ueber Parasiten in den Antheridien, Odgonien und Oésporen von Saprolegnieen. Bot. Centralblatt, Bd.
XII, p. 356 : 1882.

— ’83: Erwiderung. Bot. Centralbl., Bd. XV, p. 156: 1883.

—— ’88: Zur Kenntniss der Infectionskrankheiten niederer Thiere und Pflanzen. Nova Acta Acad. C. L. C. N. C.,
Bd. LII, p. 315; m. T. XVIJ-XXIII : 1888.

—— ’90: Die Pilze, in morphologischer, physiologischer, biologischer, und systematischer Beziehung. Breslau, 1890.

Wade Te SHUI SOD ESE

144 THE SAPROLEGNIACEH OF THE UNITED STATES,

EXPLANATION OF PLATES.

Plate XIV.

Fig. 1. A fly attacked by Saprolegniasp. xX 2.
Fig. 2. Rhizoids of 8. miata, giving rise to an external hypha, hk. x 180.
Fig. 8. Cut-off ends of byphe of Saprolegnia sp. repaired by the formation of a cellulose wall. x 200.
Fig. 4. Protoplasm and nuclei of a portion of an hypha of A. racemosa. X 940.
Picric-acid-Hematoxylin specimen ; the protoplasm somewhat retracted from the walls by the action of the acid.
Fig. 5. Nuclear division in an hypha of A. apiculata. x 1400.
. The nucleus, showing chromatin-mass, nuclear membrane, and the intermediate space.
The chromatin-mass has elongated with the rest of the nucleus.
The chromatin mass is dividing.
. The nuclear membrane is formed between the daughter-nuclei, which have not yet separated. Corrosive-subli-
mate-Hxematoxylin preparation.
Fig. 6. <A bit of LZ. lacteus, showing monopodial branching and two cellulin granules, c. x 540.
Fig. 7. Two stages in the ceveloy ment of the zc éspores of A. Americana, showing only the base and tip of the spo-
rangium. XX 390.
a. The first separation fairly marked, at 11.10 a.m.
b. The ‘“‘homogeneous”’ stage, at 11.23.
Fig. 8. A sporangium of Saprolegnia sp., with zcéspores in the act of escaping, some already out, 2. x 540. Osmic-
acid-anilin-violet preparation.

asoes

Fig. 9. Four zcéspores of A. Americana fixed at the moment of escape; from two sporangia, @ and b. X 540.
Osmic acid-anilin-violet preparation.

Fig. 10. Four spoiangia of A. Americana successively developed by cymose branching, in the order of the figures Z
to 4 ; the empty spore-membranes still adhering totwo. X 200.

Fig. 11. The tip of a sporangium of Aphancmyecs sp., with the head of spore-membranes, most of which have been
vacated ly the spores; showing a living spore, z, in its second form, its cilia not clearly visible, and a similar
spore, 2’, killed with iodine to show its cilia.

a-i, a series of stages in the development of a spore which germinated in situ, without the second swarming : a, at
10 a.m.; b, at 10.€9; ¢, at 10.14; d, at 10.19; ¢, at 10.29; f, at 10.40; g, at 11; %, at 11.45; ¢ at 12m. x 540.

Fig. 12. Two encysted z éspores of A. apiculata. X 800. Corrosive-sublimate-Hematoxylin preparation.

Fig.18. Beginning of the germination of a zodspore of A. racemosa, after one division of the nucleus. X 940.
Picric-acid-Hxematoxylin preparation.

Fig. 14. Renewal of sporangia of Saprolegnia sp. by growth of new ones into the empty membranes of old ones.
x 200.

Fig. 15. Empty, ‘‘nested,’’ membranes of successive sporangia of Saprolegnia sp., the order of their development
shown, 1—6. X 200. :

Fig. 16. A part of a sporangium of Dictywchus sp.; showing several stages in the escape of the zodspores, andy a
mature zoospore, z. X 540.

Fig. 17. Branching of hyphx below empty sporangia in Aph. scaber. X 540.

WITH NOTES ON OTHER SPECIES. 145

Plate XV.

Fig. 18. Chlamydospores of A. Americana. X 200.

Fig. 19. Chlamydospores of Achlyasp. x 74.

Fig. 20. Germination of chlamydospores of Achlya sp. X 74.

Fig. 21. Origin of o6gonium, 0, and antheridium, a, from an hyphi of A. Amzrisina. X 2)0.

Fig. 22. A divided o6gonial branch of A. apiculata, bearing three odgonia. X 200.

Fig. 23. A proliferous odgonium of A. polyandra. X 200.

Fig. 24. An odgonium of A. Americana which has reverted to the vegetative condition and given rise to new sexual
organs. X 540.

Fig. 25. Antheridial branches of A. Americana terminated by od sonium-like swellings. X 350.

Fig. 26. Four stages in the development of the odspheres of A apiculaty; a, the parietal layer still intact, the pro-
toplasm accumulating into masses, at 11.50 a.m.; 0, the parietal layer ruptured and withdrawn into the three
distinct masses, at 12 M.; c, the separation of small portions from the main protoplasmic masses, at 12.10 P.M.;
d, the reabsorption of these masses, at 12.18P.mM. X 350.

Fig. 27. A still later stage than 26, d, the odspheres quite roun ded off, at 12.23 p.m.; showing also the antheridial
branches. X 390.

Fig. 28. An odgonium of A. papillosa which has reverted to the vegetative condition and produced three hyphe with
sporangia, one of them fully shown at 2. X 200.

Fig. 29. Germination in situ of the odspores of A. Americana ; a, two spores with young germ tubes; 6, one odspore

with a fully developed hypha and empty sporangium. X 540.

Plate XVI.

Figs. 30-36. Cytology of the sexual organs of A. Americana. From Corros.-subl.-Hematoxylin preparations.

Fig. 30. Young odgonium with its central vacuole formed, its nuclei irregularly scattered. x 540.

Fig. 31. Odgonium after the formation of its basal wall, the protoplasm more withdrawn from the centre and the
nuclei approaching in pairs. X 540.

Fig. 32. The nuclei larger, fewer, and fainter, and the vacuoles formed in the protoplasmic layer. x 800.

Fig. 33. The vacuoles have disappeared and the protoplasm is more contracted. xX 800.

Fig. 34. The odspores are formed, and the antheridia have produced fertilization-tubes which contain protoplasm and
nuclei, but remain closed ; @ and b, two sections from the same o6gonium. X 540.

Fig. 35. A fully developed odsphere with its single nucleus. X< 800.

Fig. 36. Two odspheres before the final nuclear fusions. x 800.

Figs. 37-39. Saprolegnia monoica.

Fig. 37. Sexualorgans, mature. x 540.

Fig. 38. Both sexual organs from the same branch. X 540.

Fig. 39. Anintercalary odgonium. X 200.

Figs. 40-42. Saprolegnia mizta.

Fig. 40. Two small oégonia, one with and one without an antheridium, the latter formed inside an empty sporangium.
From Mississippi. x 200.

Fig. 41. An oédgonium with antheridia. From Pennsylvania. x 200.

Fig. 42. An abnormally branched sporangium, not rare in this species. From Pennsylvania. X 74,

Figs. 43-45. Saprolegnia ferax. From Kentucky.

Fig. 43. An odgonium, on a branch growing through a sporangium. x 540,

Fig. 44. A cylindrical o6gonium. x 540.

Fig. 45. Two odgonia on a forked branch. xX 200.

146 THE SAPROLEGNIACEZ OF THE UNITED STATES,

Figs. 46-49. Saprolegniu torulosa.

Fig. 46. An o6gonium with an antheridium, a rare case. X 200.

Fig. 47. Two cylindrical members of a series, the upper an odgonium, the lower asporangium. X 200.

Fig. 48. Four members of a:series, an o0gonium, two sporangia, and the lowest still young. X 200.

Fig. 49. Two odgonia in series. X 200. The pits in the odgonial walls of this species are too inconspicuous to be

brought out often with this power.

Plate X VIT.

Figs. 50-58. Saprolegnia diclina.
Fig. 50. The mouths of two sporangia appearing as if burst open by a force from within. 200.
Fig. 51. An odgonium, with numerous antheridia. x 200.
Fig. 52. A similar o6gonium on a very short branch, its pits few and small. x 540.
Fig. 53. An odgonium of the small form mentioned in the text. x 200.
Figs. 54,55. Saprolegnia asterophora. From Cambridge, Mass.
Fig. 54. A two-spored o6gonium with two antheridia; after a sketch by Prof. Trelease. x 850.
Fig. 55. A one-spored o6gonium ; from a slide by Prof. Trelease. x 540.
Figs. 56-59, Saprolegnia Treleaseana. From Wood's Holl, Mass.
Fig. 56. The only sporangium yet seen, with a zodspore, 2; after a sketch by Prof. Trelease. X 250.
Fig. 57. An hypha with two odgonia, one terminal, and one intercalary. X 74.
Fig. 58. A terminal o6gonium, without antheridia. X 350.
Fig. 59. An intercalary odgonium, with antheridia. x 350.
Figs. 57-59, from a slide by Prof. Trelease.
Figs. 60-68. Pythiopsis eymosa.
Fig. 60. Two clavate sporangia, one young, 2, and one empty, 6. X 200.
Fig. 61. Two globular sporangia, one with its escape-papilla formed aud with signs of spore-formation. XX 200.
Fig. 62. Four sporangia arising by cymose branching of an hypha. X 350.
Fig. 63. Escape of zodspores from a sporangium with several papiile, only one of which has opened ; z, three z00-
spores killed soon after their escape ; 2/, two encysted zoéspores. X 3890.
Fig. 64. A smooth-walled o6gonium with a very short antheridial branch. XX 540.
Fig. 65. An odgonium with two outgrowths of its wall; the antheridial branch longer than in 64. X 540.
Fig. 66. An odgonium with a single large outgrowth and an antheridial branch of diclinous origin. 549.
Fig. 67. An odgonium with two ripe odspores. X 540.
Fig. 68. A ripe odspore showing its excentric structure, with several oil globules. Xx 940.

Plate XV.

Figs. 69-738. Achlya Americana.
Fig. 69. A recently emptied sporangium, with the spore head. x 200.

Fig. 70. An hypha bearing numerous sexual organs. X 74.

Fig. 71. Details of odgonial and antheridial branches. X 350.

Fig. 72. A part of the ruptured wall of an oégonium, after treatment with chloroiodide of zine, showing pits. X 540.
Fig. 73. Two ripe odspores, showing their excentric structure. 540.

Figs. 74-77. Achlya meaasperma,

Fig. 74. Hypha bearing sporangia and oégonia. X 74.

7
Fig. 75. The end of an hypha, with odgonial and sterile antheridial branches. X 74.
Fig. 76. An odgonium with rather numerous antheridial filaments. X 200.
Fig. 77. An oogonium on a longer branch, with a single antheridium. X 200,

WITH NOTES ON OTHER SPECIES. 147

Figs. 78-81. Achlya polyandra.

Fig. 78. A sporangium with empty spore-membranes. X 200.

Fig. 79. An o6gonium on a strongly recurved branch, showing the separation of odsphere origins, with two antheri-
dial branches. X 200.

Fig. 80. A young odgonium, with much divided antheridial branches. x 200,

Fig. 81. Details of o6gonium and antheridia. x 540.

EOL XCLEX.

Figs. 82-86. <Achlya apiculata.

Fig. 82. Two sporangia. x 200.

Fig. 83. A young odgonium with three antheridia. x 200.

Fig. 84. An unusually recurved oégonial branch. x 200.

Fig. 85. The more typical form of odgonial branch. x 200.

,Fig. 86. Details of a small o6gonium with two antheridia. x 540.

Figs. 87-89. Achlya oblongata.
Fig. 87. Hypha with sporangium and apical and lateral odgonia, antheridia omitted. x 74.

Fig. 88. Hypha with several racemosely arranged odgonia, tending to a pointed form. From Louisiana. x 74.
Fig. 89. An odgonium with several antheridial branches. x 200.

Bigs. 90,91. Achlya oblongata, var. globosa. From Alabama.

Fig. 90. An od6gonium showing the odspores grouped at one side. X 200.

Fig. 91. Details of sexual organs. x 200.

Figs. 92-95. Achlya racemosa.

Fig. 92. Asporangium. x 200.

Fig. 93. An odgonium with a single antheridium. X 200.

Fig. 94, Details of sexual organs of the commonest form, with two antheridia. x 540.
Fig. 95. Two odspores, showing centric structure. > 540.

Figs. 96-98. <Achlya racemosa, var. stelligera.

Fig. 96. A young oégonium, with three antheridia. 200.

Fig. 97. An odgonium with a single very small antheridial branch. x 200.

Fig. 98. Details of sexual organs. x 540.

Plate XX.

Figs. 99-102. Achlya papillosa.

Fig. 99. An hypha with a sporangium and an oé6gonium. x 200.

Fig. 100. A terminal and an intercalary o6gonium, with antheridial branches. xX 200.
Fig. 101. A strongly apiculate terminal odgonium. X 200.

Fig. 102. A terminal odgonium with a single antheridial branch. x 540.

Figs. 103, 104. Achlya cornuta.

Fig. 103. Three odgonia trom the same hypha, one strongly apiculate. 350.

Fig. 104. A three-spored apiculate o6gonium. x 350.

Figs. 105-107. Aphanomyces laevis.

Fig. 105. Two odgonia from one hypha, with antheridia of diclinous origin. X 540.
Fig. 106. An odgonium thickly invested by antheridia. x 540.

Fig. 107. A young oégonium with antheridial branches of androgynous origin. X 540.
Figs. 108-111. Aphanomyces scaber.

Fig. 108. An odgonium of the rough form of the species, on a short, lateral branch. x 540.

148 THE SAPROLEGNIACEZ OF THE UNITED STATES, ETC.

Fig. 109. Two oédgonia on the same hypha, the lower abortive, the upper with an antheridium. X 540.

Fig. 110. An odgonium of the smooth form of the species, with an antheridium. X 540.

Fig. 111. An old odgonium, with a ripe odspore and no antheridium. X 540.

Figs. 112-114. Dictyuchus Magnusii. From Cambridge, Mass.

Fig. 112. An empty sporangium showing some of the openings for the exit of zodspores; froma slide by Prof. Tre-
lease. X 200. ;

Fig. 113. An odgonium with single odspore and antheridial branch. X 500.

Fig. 114. A young o6gonium with antheridial branch. Xx 500. The last two after sketches by Prof. Trelease.

Figs. 115-118. Leptomitus lacteus.

Fig. 115. Anempty and a young sporangium, formed from successive segments of an hypha. X<-200.

Fig. 116. The same, showing also the peculiar branching below a sporangium. XX 200.

Fig. 117. Zodspores encysted within a sporangium. X 200.

Fig. 118. Encysted and germinating zodspores, and empty membranes pointing to diplanetism. x 540.

Figs. 119-121. Apodachlya completa. From Louisiana.

Fig. 119. Young sexual organs. xX 540.

Fig. 120. Adult sexual organs, with ripe odspores. x 540.

Fig. 121. Details of sexual organs, with peculiar structure in antheridial branches. x 940.

NotTE.—All drawings are from specimens obtained at Amherst, Mass., except where the contrary is noted.

Plate XIV.

Transactions Amer. Philos. Soe. Vol.XVil. Part Il.

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_ MORPHOLOGY OF SAPROLEGNIACEAE.

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CyroLoGy. S. MONOICA, MIXTA, FERAX, TORULOSA.

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9. DICLINA. ASTEROPHORA, TRELEASEANA. P CYMOSA.

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RACEMOSA.

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ARTICLE VI.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.
BY FRANCIS C. PHILLIPS, PH.D.

Read before the American Philosophical Society, March 17, 1893.

CONTENTS.

I. Phenomena of Oxidation of Hydrogen, Carbonic Oxide, Gaseous Paraffins,

Olefines and Acetylene.

II. Qualitative Reactions of Gases.

II. Substitution Products of the Action of Chlorine upon Methane.

IV. Preparation of Halogen Compounds of Allkyls and Olefines.

V. Composition of Natural Gas as found in Western Pennsylvania and other
Regions.

VI. A Method for the Quantitative Analysis of Natural Gas.

VII. Origin of Natural Gas and Petroleum.

INTRODUCTION.

The purpose of the following research, as originally begun, was to study ex-
haustively the composition of natural gas as found in Western Pennsylvania. Dur-
ing a series of analyses by Bunsen’s methods, using eudiometers calibrated with
great care, and making readings by means of a Grunot cathetometer of superior
construction, many difficulties were encountered which were not easily overcome.
More exact methods for the positive identification of the various constituents of a
gas mixture seemed necessary, and finally a study of the qualitative reactions of

gases was undertaken. Since the publication of Bunsen’s Gasometrische Methoden,
ASP. 8.— VOL. XVIL T,

150 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

the introduction of the various forms of apparatus proposed by Hempel and Winkler
has tended to greatly simplify quantitative gas analysis.

The majority of absorption gasometric methods are based upon the assumption
that the contraction undergone by the volume of a gas on exposure to a liquid reagent
is not only a measure of the percentage of a particular constituent of the gas mix-
ture, but that the identity of such constituent is established by the same operation.
This assumption is very often warranted by the facts, but occasionally leads to error.
Qualitative methods, for the recognition of different gases, have usually been held
wholly subordinate to quantitative absorption or explosion methods. Quantitative
analyses are far more reliable if the constituents to be determined can be positively
identified by independent methods; and it is somewhat strange that, heretofore, the
qualitative side of gas analysis should have received so small a share of attention.
In the following work, an attempt has been made to collect together the more impor-
tant reactions of the commonly occurring gases. The results must be regarded as
a first attempt only, inasmuch as improved methods of preparation and purification
will doubtless involve the necessity of corrections in certain cases. Accurate methods
of qualitative gas analysis are likely to prove of increasing importance in the study
of the atmosphere, in the laboratory and in the chemical arts. The following sub-
division of the subject has been found convenient:

1. Phenomena of oxidation of hydrogen and hydrocarbons by air in presence of
finely divided metals and other oxidizing agents.

2. Reactions of gases towards various metallic salts and other compounds used
in solution, and in a dry state at high temperatures.

——

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 151

I. OXIDATION TEMPERATURES.

PREPARATION OF PALLADIUM AsBestTos.—Long-fibred asbestos, washed by
hydrochloric acid, dried and weighed, was moistened with palladium chloride solu-
tion. Alcohol was dropped on the asbestos and ignited. After burning off the
alcohol a few times, the asbestos was heated in a Bunsen burner flame, and the treat-
ment with palladium chloride and alcohol repeated. With care, it is possible to
obtain a fairly uniform coating of palladium, although the metal tends somewhat to
collect on the surface of the fibres. Asbestos fibre, containing an amount of palla-
dium equal to 6 per cent. of the total asbestos plus palladium, was used in the fol-
lowing experiments :

About 0.3 gm. of this asbestos was placed in a glass tube of one-eighth-inch
bore. This tube was then heated in an iron oven, having its lower portion filled up
to the level of the glass tube with iron turnings, so that the glass tube rested on and
was partly covered by the turnings. A thermometer was inserted into the turnings.
In some of the experiments the apparatus described on p. 154 was used. In the Be- |
richte der d. chem. Gfes., 1879, pp. 636 and 1006, two articles appeared by W. Hempel
on the determination of hydrogen in gas mixtures by means of palladium sponge.
In the former article it is proposed to remove the hydrogen by occlusion: in the
latter, by oxidation. Winkler, in his Technical Gas Analysis (p. 81), employs palla-
dium asbestos for oxidation and determination of hydrogen in presence of methane
(and other paraffins), in water gas, coal gas, etc. In order to study the limits and
possibilities of these methods, and their applicability to various gas mixtures, the
following experiments were made:

1. Hyproecren.—Hydrogen is not easily obtained pure; all authors who have
had occasion to study its properties agree upon this. The purest zine contains car-
bon, and hydrogen made by the action of sulphuric acid upon this metal is contami-
nated by traces of hydrocarbons. Other metals have been tried. Aluminium was
dissolved in sulphuric acid and also in caustic soda solution; magnesium and cad-
mium were dissolved in hydrochloric acid ; sodium and potassium in water. In every
case, however, the hydrogen evolved contains hydrocarbons, as was shown by the
production of carbon dioxide on burning. After various trials, the following plan
has been found to give satisfactory results: The purest zine obtainable (such as is
sold in sticks for use in Marsh’s test for arsenic) was dissolved in dilute sulphuric
acid, The gas was passed (1) through a 6 per cent. solution of permanganate of

152 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

potassium acidulated by sulphuric acid; (2) through a glass tube containing cotton
coated with precipitated oxide of copper; (3) through alkaline permanganate ;
(4) the gas was kept in contact with bromine water for twenty-four hours; (5) well
washed by soda solution (for the action of copper oxide as a purifying agent for
hydrogen, see Lionet, Fresenius Zeitschrift, 1880, p. 344). I have found precipitated
carbonate of copper in moist condition to answer better than the oxide, especially for
removing sulphuretted hydrogen. Hydrogen so purified contained only traces of a
paraffin which, calculated as CH,, amounted to less than 0.02 per cent. of the hy-
drogen. By very careful tests no phosphorus, arsenic, sulphur or antimony could
be found.

Expt. 1.—A mixture was made of hydrogen and air in the following proportions:

This mixture, contained in a gas-holder, was caused to flow slowly over 6 per cent.
palladium asbestos, which was contained in an one-eighth-inch glass tube heated in
the oven. ‘The rate of flow of the hydrogen and air mixture could be controlled by
causing it to bubble through sulphuric acid before entering the palladium asbestos
tube. Some anhydrous copper sulphate was placed in the far end of the palladium

tube, which by its change of color to a bright blue serves as a delicate moisture
indicator.

TEMPERATURE OF ASBESTOS TUBE. ; RATE OF GAS FLOW. RESULT.
PMO AROMA OOrO DOB OC US Stoo oo aoeon 100 cubisicent. sin hive mine. 26 oetsse se elein pe -No moisture.
BOOS Sekih ere Hak verter ele Ge eee ee Set ‘ BGG eg Bet cca On re saeear cache ss nF
MORE aia t cits COR Cees RCO Ee GORE GG GOP pe Bian GE Bt els Ee oe NE Tae ae se
bt OR aaiye HERES Hts Fike AION ASS MO ok Coens: Cake GS Gl OE Ter ae Re hae COE rae Moisture formed.
UMASS ER TOTES OOO EG DTCC ae. aG 2 UG ees “OG 6G Na Scherer eine eat tateess No moisture.
DOO aevelere cra evsieioye louse sloicielerern a een eee BG 2 G6 2 OGi oF Gb cL z be aye
AQON os Se eene aioe ceed G0) 8G Bie BE Ge : RH a Sie -
DOS se Saeco Rages: cd ent ee rama eae ane ‘ : “s ee
BDO SGisis, de stew casa tle aie oadeionr ole eigen Be Ss Be oe oe RG SE BAUS EP DENTS ar ere Moisture formed.

Hence, absolutely dry hydrogen is not easily burnt by palladium asbestos below a
temperature of 50°-60°.

At the above rate (100 ec. in five minutes), there is a strong tendency to cause
glowing of the palladium asbestos, not throughout, but in minute points where the
palladium had accumulated in thicker particles. This glowing may take place while
the tube is at any temperature between 15° and 100°, and depends wholly on the rate
of flow of the hydrogen mixture. It is independent of the temperature outside the
tube, and it is therefore not possible to prevent or arrest it except by reducing the

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 153

rate of flow. The hydrogen by its rate of burning determines the temperature, and
the low specific heat of the palladium and feeble conductivity of the asbestos neces-
sarily increase the tendency to glow. Using air and hydrogen (5:1) repeatedly, no
explosion ever occurred, although the palladium often glowed with great intensity.
This is also true of palladium asbestos containing 30 per cent. of palladium, and
when the temperature was carried to 135° C. Air containing only 1 per cent. of
hydrogen may cause intense glowing of the palladium if the rate of flow is rapid.
Immersion of the tube in cold water will not prevent glowing. Caution is necessary,
should a mixture of oxygen and hydrogen be exposed to palladium. In experiments
made with tubes of one-millimeter bore, and at a temperature of 100°, it was found
that the hydrogen in burning causes a series of sharp explosions, very different from
the quiet and slow oxidation which invariably characterizes the mixture of air and
hydrogen.

Expt. 2.—To determine the degree of completeness of the oxidation of hydrogen
by palladium asbestos.

The palladium tube was heated to 60°-70° C. Gas escaping from the palladium
tube was passed through oil of vitriol and phosphoric anhydride, in order to dry ;
thoroughly; then through a second (porcelain) tube containing palladium asbestos;
and finally into a small weighed tube of phosphoric anhydride. The second palla-
dium tube was heated to intense redness. It was found that absolutely no moisture
was formed in the second contact with palladium, although 5 liters of the gas mix-
ture were used and the rate of flow varied from 40 to 100 bubbles per minute. It
was shown, moreover, that complete oxidation is independent of the glowing of the
palladium.

Hence the oxidation of hydrogen by air in presence of palladium is complete at
a temperature of 60°—70° when the gas mixture is dry. Quantitative experiments,
to be detailed later, showed that in the case of air containing 0.2 of hydrogen a cor-
rect determination of the hydrogen was possible. The temperature in this case was
100° C. Ifthe hydrogen and air mixture is moist, oxidation is easily and completely
attained at ordinary temperatures.

Hydrogen is said to ignite at a temperature of 552° C. (Le Chatelier, Bull. Soc.
‘Chim., 1883, p. 2).

Kept. 3. Gold Asbestos.—

UIP 6.5 6a 6a CO BOOTS Eo d HEHE NT OR DNC GOOLIGO HAR EHS Ce DS CACRCROIN ED iD OCCA TIC APO Coen anni acini sea tamer 90
ELMO REMI Ele hee Se lett R CIES Fes os Sinlate cv ieloinrg Ges cise leleiwidinrelaists e arslelal Mikeletoio ape gate be desk ce alc dese cem 10

154 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

No change occurred till the gold asbestos was strongly heated over flame, and even
then the oxidation was exceedingly slow, so that repeated passages of the gas were
required to produce complete oxidation. In the preceding experiment a Hempel’s
apparatus was used.

Expt. 4. Platinum Asbestos.—

The results were scarcely distinguishable from those obtained with palladium asbes-
tos. Palladium causes oxidation with somewhat greater intensity and at lower
temperatures. Determinations of hydrogen in mixtures of known proportions, using
a Hempel apparatus, gave very correct results.

Expt. 5. Lridium Asbestos.—

When used in a Hempel apparatus in the cold or at 100° C., iridium seemed to have
very little influence, causing only a slight contraction in volume, even after the gas
had passed the iridium many times.

EKxpt. 6.—
I Wh aR Seno Gn cob oom Ouer Goan ceE np cA oLcoSeEoo bor CpoupedniedaSsscobo diac nanbaddaacsn ce oO S48 = 90
LEN YOO Joos do UD GOO CH nbY be nbonDDNd doo IM and obasO SONbSuOORDORO HOMO AOIGSoSogs sat ooass soesescos 10

Palladium asbestos was moistened with a solution of carbonate of potash and dried
at a heat which was insufficient to cause fusion or sintering. In several trials the
alkali was found to seriously retard oxidation of the hydrogen, which was not fully
burnt until the gas mixture had been repeatedly (in one case ten times) passed
through the tube at 100°.

HYDROCARBONS.

Description of Apparatus.—A, is an iron gas pipe, six inches in diameter and
thirty-four inches long, closed at both ends by heavy asbestos board. Four iron
pipes of three-sixteenths-inch bore are placed in the centre, passing through the
asbestos ends, and giving the apparatus the appearance of a boiler with four flues.

B, B, are two side necks of one-half-inch pipe. The whole interior space around
the four small iron pipes is filled with iron turnings. Glass tubes of one-eighth-
inch bore, containing the metal-coated asbestos or other reagent, could be pushed
through the small iron pipes. Thermometers were placed in the side necks B, B.
Supposing the arrow to represent the direction of flow of the gas current through
the gas tubes, the metal-coated asbestos was, in the experiments, placed at the

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 155

point D, and of the two thermometers E was kept a few degrees higher than F’, the
purpose being to have the gas heated nearly to the temperature of the hottest part
of the oven before it reached that point. Thus it was not possible for the gas stream
to exert a cooling effect upon the metal-coated asbestos. This apparatus is superior
to an ordinary sheet-iron oven, as the glass tubes are heated by actual contact rather
than by radiation. Repeated trials have shown that if a thermometer be inserted in
the side neck, and a second one in one of the long, horizontal iron tubes, the differ-
ence in the indications of the two thermometers will amount only to an insignificant

F E

(Eee e ere eee B
> ors ——— i iba Se = SS a SS SS a = SS SS SS SS ES SS eS Sa ea Aes Di
SSS SS

Tron oven used in experiments upon oxidation temperatures.

fraction of a degree Centigrade. Nitrogen-filled mercury thermometers were used
up to 300° in the following experiments, and in order to measure higher tempera-
tures, metallic salts of known fusing point were employed. A few grains or crystals
of the carefully purified salt were placed in a fine glass tube previously drawn out
to a point. Such a tube was placed in the side neck of the iron oven and plunged
into the iron turnings. The temperature of oxidation of the hydrocarbon gas could
then be ascertained to occur between the melting points of two salts. This method,
which is simply an adaptation of the process commonly used for the determination
of melting points, proved very satisfactory. It was not possible to employ an air
thermometer, as this would have necessitated an inconyeniently large oven. The
following list of substances, with their melting points, includes those which were
used in the experiments detailed below.

COPASSIUITIU ITU AUCH Nee Sec tctat crore ievare aie altro cle eletctetonchel aie fotar ele tello, stala, olegeid elaseiniave eich ais » sibkatew dereaiat wale sigs 339°
PLOLASSIUIMMC HI OLALENsetterersierere arco lave aielataiaicrole clare uc erctereteiahersiolevs aialalacolaicre creiatetstalefalsteicteleveisaileieieictescpidars 359°
banal TOG, shoaathiows SoSEO NOCD OCG OO OSI HO doco UOC CCU SOI ZO TROD OCIS OUUICOr In DOO UDB COG OOCIn SAE ei Ets 3839
Ce LCUTIANLITTIE BIO CHA ERE ecetyae tates ts sare oieiexs o's«1n ratni@ere nielalsalele.s'e/erelalel clots) share’ wiufeloiciens/ote’sisieve.e ele; tierarsieicrs'elwle.c ea « 404°

SRI MCMC ALCP Ret Tee Riera ca hrclore Giclee ah selai ic etareohetdaotmics Giecaoteottae alaalelale oiate caste nW cid acishialele cpicior 414°

156 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

"Thallium: 1Odide 2 «5 .35;0\5 evaiaveia ofe'erelereitie.sum etre cone eke peinrer sibel tis ataisie eisicieiaia vias aise piste sietsisiieis Steers aioe 439°
Tread CHIOIde o aie x sreiccierth parcrereretereieis aja) ole ce evettelotsteletsiner heise intele ersisleeieseieie ce Siecle aie eee meee ae eeenee 498°
Silver Dromide 2.15 caioe oie siete cies Aioiciere wovarolerereleletarte: Moker eve ic leisekereleraievetereincr set nena ele reer eee ee 527°
Potassiwin’ 10d ates 3. eas Aceatien siscie re detendis tain trols Sieidie aie wie ae eielnie ie ayeiicictee eye late elo ae ee ere eae 582°
Bamitam, “itr ate icaye as cue 3. ocoB ake 2 0c lo: anya sd jarstete le ates arcana opate aye tebohavsreferete aise ie ene atthe Sitar eerie eat ere eas 598°

(Landolt and Bornstein’s Tables and J. Ch. Soc., 1888, p. 63.)

The following general method was used in studying oxidation temperatures of
hydrocarbons: ork |

Air containing a small measured percentage of the hydrocarbon was agitated
with caustic soda solution to remove carbon dioxide. It was then caused to flow
through the bottle (G) containing lime water. This served to show whether the gas
had been completely freed from CO,. The gas then traversed the palladium asbestos,
or other reagent contained in the glass tube in the oven, and finally a second bottle
of lime water (H). On heating the oven, the temperature of oxidation of the hydro-
carbon could be recognized by the precipitate of carbonate of lime in the second
lime water bottle. As an indicator for CO, in the oxidation experiments, solutions
of baryta strontia and lime were all tried. The solubilities of the carbonates, accord-
ing to Fresenius, are as follows:

JoPK CO Raoniay aonb aco UUoodooun OCU ouSodoo OCOD CORD a udo OL Hida dboncoeababec one part in 14,137 parts water.
ISLC Oa iveter etehetare efelerererelcfatel fel stefelerele/aieierel=tatel sinter eatetencferatefole rete t=taletetalctetetetstsiciets $e ES a 8 045 ges <e
OF 610 Rees aE eon nee ne aM InSO OnE Bosh SATO U Sec GOS IS OS AGSOSNGOO Soak eso eal Os GO Momence. Es

Baryta water appears to be the most delicate test. On account of its extreme
sensitiveness, however, it is not easily preserved free from turbidity, and lime water
was found sufficiently sensitive for almost all purposes. The same general method
above detailed was used in all the following experiments. |

It seemed desirable at the outset to test the question, Do the hydrogen and car-
bon of a hydrocarbon burn simultaneously ?

In the oxidation of a hydrocarbon in presence of excess of air, it seems probable
that the hydrogen and carbon must burn simultaneously to H,O and CO). It is
possible, however, that under the conditions above described a selective oxidation of
hydrogen might occur, involving the formation of a condensation product.

Thus CH, might yield acetylene :

2 CH, + O, = 3 H,O + C,H, and no CO,,.
2 CH, might yield C,H, ;

2 CH, + 20=—C,H, + 2 H,0 and no CO,.

As reagents for the detection of moisture in a gas, the following substances
were tried:

Anhydrous cobalt chloride, anhydrous copper sulphate, phosphoric anhydride,
a mixture of green vitriol with ferricyanide of potassium, the green vitriol being in

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. Loe

its crystallized form and containing therefore 7 mols. water. This salt and the ferri-
cyanide of potassium were ground separately and mixed just previously to the ex-
periment (anhydrous sulphate of iron was found not to give satisfactory results).
A little of the mixture placed in the end of the glass tube was found to be a delicate

indicator for moisture, assuming quickly a deep blue color.

Eupt. T.—
AAUP So neice op DG AbONdH Se 64 ono 2UOd ae Con UNG o CON OnbU no OO LOnOt ras OOUd Ub aad e Uertior DEODHEDGOCOMR OS» 96.9
IVI Do Gano ae deb OOO SHAUN ag DOES ESOODS DOOOR NON Ido bo SEB RREDbS O55 5 Nano COneD OCOD Den pReneGooCs 3.1

This gas mixture was passed through soda solution and then dried by oil of vitriol.
It then traversed the palladium asbestos, which was gradually heated in the oven.
At the far end of the same glass tube the gas passed over about 0.1 gm. of the green
vitriol and ferricyanide of potassium mixture (cold), and finally into lime water. It
was found that the lime water became milky a few moments before the powder turned
blue. This change to blue took place, however, immediately afterwards and before
any further increase in the temperature of the oven had occurred. As the lime water
is a much more sensitive reagent towards CO, than is the green vitriol mixture
_ towards moisture, it is natural that the CO, should produce its effect a little in
advance of the water vapor. Similar experiments were tried with methane. he

results were the same as with ethylene.

Hzxpt. 8.—
IMR ASE een teen ee eet ee ce tee eee e ene e tees eset en en eteseeeeseeeeeessceesessseee ress asenencs 96.9
BEE fi lachirn Oe cater cae rcaavcter Seas eeeveioveceye eve steve merers ravejotcrekctslcisla7sieisia Sree oisiaye eu ie le(oles oipeeiy ibis eit ieinicielne wimeaje nele ctw ete 3.1

This mixture (moist) was found, after passing the palladium asbestos, to cause no
- reduction in palladium chloride solution (see reactions in solution), and hence no oxi-
dation of CH, to C,H, had occurred. There is therefore no reason to suppose that,
under the circumstances which prevailed in the apparatus above described, either
constituent of the hydrocarbon is oxidized before the other. The hydrocarbon yields
directly CO, and H,O.

PARAFFINS.

2. MetTHANE.—This hydrocarbon was prepared by the method of Gladstone
and Tribe (Jour. Chem. Soc., 1884, p. 1541). Methyl iodide of normal boiling point
was caused to flow in admixture with alcohol upon “copper-zine couple.” The resulting
gas was freed from alcohol vapor by oil of vitriol. It was then washed with bromine
water, and the bromine vapors subsequently removed by ferrous sulphate solution.
Finally it was passed over dry palladium chloride at 50°, to remove any possible

“A. P. S.—VOL. XVII. U.

158 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

traces of hydrogen. The following explanation of the reaction is given by the
authors cited:
CH,I + Zn (Cu) + H,O = OB, + ga ee

- 200 c.c. of the methane so prepared were burned, and the products aspirated through
soda solution. On testing the latter for halogen, no traces could be found. From
this it was evident that no vapor of methyl iodide had escaped decomposition by the
zine. Methane is obtained when chloroform dissolved in alcohol is dropped upon
zinc powder.

CH,Cl + 3 5,0 4- 6 Zn = 8 Zn0 + 3 ZnCl, 4 2 CH,

(Sabanejeff, Ber., IX, p. 1810). This method was found to give very satisfactory

results. The process usually given in the text-books, by heating acetate of soda

with alkali, is very unsatisfactory both as regards purity and quantity of product.
Expt. 9. Palladium Asbestos.—

TG tame « sa ,a.e-syecara's nests Cavey waste: aval, Saavevra wer cae ay ayaie eheracouaT arr OUST ETS Ieee Ia rig oh eS Ee eee eee 3.1

Oxidation to CO, occurred at the following temperatures:

(1) Above melting point of Cdl, (404°).

Q) oe « & aT, (4049).
(3) « « « «© Ba (Cl10,), (4149).
(4) ce ee ce «ec CaI,,.

()peee z «© «© Ba (Cl0,), (4149).

In the above trials methane from methyl] iodide was used.

The preceding experiment was repeated, using methane from chloroform. In
six different trials the temperature of oxidation was found to be between the melting
points of Cdl, and AgCl (404° to 451°). In one trial, oxidation occurred consid-
erably above the melting point of AgCl.

The temperature of oxidation of methane is therefore extremely high as com-
pared with that of hydrogen.

Hempel, in his excellent work on gas analysis, says that methane prepared from
sodium acetate is oxidized by palladium at 210°. My results do not confirm this
statement. ‘The difference is possibly due to impurities in the methane.

Expt. 10. Palladium-Platinum Asbestos.— 2

Asbestos was moistened alternately with palladium chloride and platinum chloride
and the metals reduced by burning alcohol, as already described, the object being to

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 159

produce an intimate mixture of both in finely divided state. Oxidation occurred in
four trials between the melting points of Cdl, and AgCl.

The mixture of the two metals is, therefore, no more efficient than palladium
alone.

Hxpt. 11. Platinum Asbestos.—

Oxidation occurred in five trials at a temperature just below the melting point
of AgCl.
Expt. 12. Gold Asbestos.—

Oxidation occurred at a temperature of dull redness. In this last experiment a
Hempel apparatus was used.

According to Mallard and Le Chatelier, methane inflames at 780° (Ann. des
Mines, 1880, p. 201).

3. HTHANE.—This gas was prepared from ethyl iodide by the method of Glad-
stone and Tribe already described. The resulting gas was purified from alcohol —
vapors by prolonged contact with oil of vitriol. It was then treated with potash
solution and with palladium chloride (dry). 200 ¢.c. of the gas so purified yielded,
on burning, no trace of halogen when the product of combustion was aspirated
through potash solution.

Expt. 13. Palladium Asbestos.—

IBNINGAS aoctecs Goled clo SU AEE OOO Cer ER Or OTRO ORGS CECI aC CCR EL a RCA TIE CSIR aeTP a IAC Rea tera ears a 3.1

In several trials made with ethane, the temperature of oxidation was found to be
between the melting points of cadmium iodide and silver bromide. Parallel trials
were then made, using air containing 3.1 per cent. of methane (from methyl iodide) _
in one tube and 3.1 per cent. ethane in the other. Both tubes were charged with
portions of the same lot of palladium asbestos, and both were heated simultaneously
in the iron oven, so that the conditions to which the two gases were subjected were
as nearly as possible identical. In ten trials oxidation occurred in both tubes in the
neighborhood of the melting point of silver chloride; but it was noticeable that the
methane was oxidized in eight of the experiments a little earlier (and hence at a
slightly lower temperature) than the ethane. The more complex hydrocarbon C,H,
is at least as stable, and probably somewhat more stable, than the lower CH, A
parallel case is probably to be found in the difference in stability of the correspond-

160 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

ing alcohols towards reducing agents. Methyl alcohol is decomposed on warming
with powdered zine, with formation of CO and H, while ethyl alcohol is unaltered
except at a red heat (Jahn, Grundsitze der Thermochemie, p. 150).

4, Propanr.—This hydrocarbon was prepared by Gladstone and Tribe’s method,
from isopropy] iodide and “ copper-zine couple.” The reaction is much slower than
in the case of methane and ethane; the yield is, however, satisfactory. ‘The same
method of purification was used as in the case of methane. The gas was found to
be free from iodine compounds.

Expt. 14. Palladium Asbestos.—

PYOPAN C5 so5isiaie bare "er hese Westerns Se Biw 8 Sin wry einvo eh abara ve SEEMS ose elasellac RUatale Wlojel era ere eicharotaretelen crete chem ote eee a chomee ea 3.1

Oxidation occurred at the following temperatures:
(1) Above melting point of potassium nitrate (339°).
(2) Just below melting point of potassium nitrate (3399).
(3) “é above ce “ce ‘ec “cc “ce (38392).
(4) Just below melting point of lead iodide (383°).
(5) At melting point of potassium chlorate (359°).
(6) “ce cé “ce ce “cc “cc (8592).

5. IsoputaAne.—This hydrocarbon was prepared by the method of Gladstone
and Tribe from isobutyl iodide and “ copper-zine couple.” It was purified by the
method followed in the case of the preceding hydrocarbon, and was proved to be
free from iodine compounds.

Kept. 15. Palladium Asbestos.—

TgODtta Mes ais aieinccce sce a a 0s erosaresete le rarer Tavaloie. oe vai ere la ake nee kore are rete ieTeraie tert naioietereletCieteteter ie sic tierateriereters 3.1

Oxidation occurred at the following temperatures :

(1) At 236° (3) At 250° (5) At 225°

(2) * 9250 (4) « 9200 (6) “ 250°

Hxpt. 16.—The same mixture of air and isobutane was conducted over ruthen-
ium asbestos (prepared by the use of ruthenium chloride in the same manner as the
palladium asbestos already described). Oxidation occurred at the following tem-
peratures ;

(1) At 250° (3) At 230° (5) At 2220

(2) « 236° (4) « 995° (6) * 214°

As regards this more easily oxidizable hydrocarbon ruthenium and palladium
have almost the same action.

6. PENTANE.—Petroleum gasolene, which had been kept several weeks in con-
tact with concentrated sulphuric acid, was fractionated and the fraction, boiling at

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 161

about 37° C., was used for the following experiments. It was mainly pentane, as
was shown by a vapor density determination, but contained, no doubt, small quanti-
ties’ of other low-boiling paraffins. Purified air was aspirated through a Woulfe
bottle containing a little of the liquid.

Ezxpt.17. Palladium Asbestos.—Oxidation occurred :

(1) At 210° (3) At 180° (5) At 210°

(2) “ 2000 (4) “ 170°

7. Heprange.—‘ Theoline,” a commercial product formerly replacing benzol in
the San Francisco market, and manufactured by distilling a resin from the tree
Pinus sabiniana, was shown by Thorpe (Chem. Soc. Jour., 1879, p. 296) to consist
of normal heptane in an impure state. By digestion with oil of vitriol the paraffin
is obtained pure and of constant boiling point (between 98° and 99° C.). Heptane
was the highest paraffin used in the trials of oxidation temperatures. As this hydro-
carbon is readily obtained in a state of purity, and as it was the most complex par-
affin employed, it seemed desirable to ascertain whether, on oxidation by palladium
asbestos, any unsaturated hydrocarbon resulted.

Expt. 18. Palladium Asbestos.—Air was aspirated through a Woulfe bottle
containing heptane and then through the heated palladium asbestos tube. Oxidation |
occurred at the following temperatures:

"(1) At 270° (3) At 280° (5) At 300°

(2) “ 270° (4) “ 2750 (6) “ 2900

While the experiment was in progress, the air escaping from the palladium
asbestos tube was passed through soda solution to absorb the CO, formed, and then
into palladium chloride solution and finally into lime water. The palladium chloride
was reduced to metal and the lime water following it was rendered milky (see reac-
tions of CO in solution). This result occurred only when the air was insufficient
for complete oxidation of the heptane. With an excess of air, only CO, and H,O
were formed, and no unsaturated hydrocarbon could be detected (olefines and acety-
lenes would have caused a reaction in palladium chloride solution; see reactions of
these hydrocarbons in solution). It seems, therefore, that oxidation of the paraffins
Os Corea s haters (ois C,H,. (even when carried on at the lowest possible temper-
atures) by excess of air in presence of palladium asbestos yields only CO, and H,O,
although by no means in quantities proportional to the amount of the hydrocarbon
originally used.

OLEFINES.

8. ErayLeNeE.—This hydrocarbon, on account of the ease with which it is pre-
pared and its low temperature of oxidation, is well suited to the study of reactions,

162 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

and it has received in the present work a larger share of attention than any other
gas.

Ethylene was prepared by the method of Erlenmeyer and Bunte (Ann. der
Chem. u. Pharm., Vol. CLX VIII, p. 64). The yield is, however, small as compared
with the theoretical. The older method of Mitscherlich (Kolbe, Lehrb. d. Organ.
Chem., Vol. I, p. 349), according to which the vapor of boiling alcohol is led into a
mixture of 10 parts sulphuric acid and 3 parts water, at a temperature of 165° C.,
yields more ether than ethylene, although it possesses the advantage that frothing
is avoided. Whatever the strength of the sulphuric acid used, there is always pro-
duced a large proportion of ether which cannot be absorbed by rapid bubbling
through sulphuric acid. Part of this ether vapor is removable by agitation with a
large volume of cold water. Its complete removal requires prolonged contact with
oil of vitriol. The gas was purified by soda solution containing bichromate of potash
and digested with oil of vitriol for several days.

Ethylene was also prepared by the action of zinc upon C,H,Br, (J. Ch. Soe. (2),
XII). Hthylene dibromide dissolved in 2 parts aleohol was introduced by tap fun-
nel into a flask containing zine powder, and connected by a reversed condenser with
a gasometer. The same method of purification by sulphuric acid was used as in the

preceding case. This method is in every way very satisfactory for the preparation
of small quantities of ethylene.

Hapt. 19. Palladium Asbestos.—

Bthylemecnxs <3)sfsiste;s apeictee olete eteleters olokalctefotels eualcle sie erate tetera va amie Lao Dieelel sie oot Te tetole et tae nie clet anette eet 3.1

FATT. 2 whe gcc Sie austere wdtd alevase Sho (S verebwye coseng Bl anclle a teher ese ln vole OV Ie RAR OTS PST epGEs STATO” <aee TOT Ie Vet en es eo ate iat aaa te tar aerate 96.9
Oxidation occurred:

(1) At 210° (4) At 200° (7) At 224°

(2) « 1800 (5) 220°

(3) «© 2240 (6) “ 191°

The ethylene burns therefore more easily than either methane or ethane.

Haupt. 20. Palladium-Platinum Asbestos.—The same mixture of ethylene and
air was used. The range of temperatures at which oxidation occurred was about
the same as in the case of the preceding experiment, showing that the mixture of the
two metals is no more efficient than palladium alone.

Kapt. 21.—
NAY v5 oie,g'ai ot» solos sle\o,0 0 0 /0/a\0°e)sfoisisis/alsitels (sfeieir) sfetevofetele ie tere (aisieceintals|giclel ate ateiaiaiots tetera si ainine eae ee 96.9
EUW lene: . ... cs ccicie'eie 0 e10 nls wisie d seiare oterslntevelfe rare Sis di erel aves etoininielel Siseie oie cisiaia ols ereinetet eieiaie enero ee ntetate 3.1

30 per cent. palladium asbestos was moistened with cobalt nitrate solution, dried and
ignited in order to coat the asbestos with peroxide of cobalt. On passing the gas
mixture, carbon dioxide was produced at the following temperatures :

(1) At 2770 (2) At 250° (3) At 260°

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 163

Hence, the presence of an easily reducible metallic oxide does not seem to
increase the oxidizing action of the palladium.

Haupt. 22.—Several trials were then made in order to ascertain whether by the
same general method ethylene could be exhaustively burned. It was found that,
using air containing 3.1 per cent. of ethylene, oxidation is only complete (7%. ¢., to
CO, and H,O) when the palladium asbestos is brought to a temperature of bright
redness. Ata dull red heat the hydrocarbon may pass partially unburnt. <A plat-
inum wire spiral (heated by an electric current) was found to be less efficient than
palladium asbestos.

Eapt. 23. Absorption of Hthylene by Palladium.—Pure ethylene (%. e., unmixed
with air) was passed over 2 gms. of finely divided palladium contained in a Hempel
tube heated to 100. A considerable absorption of the gas occurred, varying in sey-
eral trials from § to 5 c.c., according to the duration of the experiment. Unmixed
with an excess of air it appears, therefore, that ethylene may undergo an absorption
which might cause serious errors in a quantitative gas analysis. With palladium
asbestos (6 per cent. palladium) no occlusion of ethylene sufficient to effect the vol-
ume of the gas could be observed. | .

EHapt. 24. Ruthenium Asbestos.—

Oxidation occurred at the following temperatures :

(1) At 2940 (3) At 2740
(2) « 281° (4) “ 28200

Expt. 25. Osmium Asbestos.—

Owing to the volatility of osmium in the form of oxide, some difficulty was found
in preparing osmium asbestos. Osmic acid was reduced by alcohol and the reduced
metal spread upon asbestos. Oxidation occurred at the following temperatures :

(1) At 150° (5) At 116° (9) At 160°
(2) ‘* 140° @) als ; (10) ‘© 1359
(3) « 1850 GOS
(4) <“ 120° (8) ‘* 160°

In the preceding experiments it has been shown that oxidation of the hydro-
carbon does not occur each time at the same temperature. ‘The variations are often
so great as to preclude the supposition that a cause is to be sought in different con-

164 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

ditions of the experiment. ‘To ascertain as fully as possible the limits of variation
in the temperature of oxidation, the following trials were made:

Expt. 26.—Instead. of metal-coated asbestos, a platinum wire one millimeter
thick and one inch long was placed in the one-eighth-inch glass tube in the oven.
The same mixture of air and ethylene was used as in the preceding experiments. As
in all previous work, the oven was allowed to cool down after each trial and before
the next one was begun. In every case the temperature was very gradually raised
until oxidation, as indicated by the precipitation in the lime water, occurred. The
gas stream was carefully regulated, being maintained at a uniform rate in all the
trials. Oxidation occurred at the following temperatures :

(1) At 2700 (9) At 300° (17) At 220°
(2) “© 290° (10) «* 265° (18) «© 255°
(3) “390° (11) “ 210° (19) « 2100
(4) “« 290° (12) “ 2170 (20) <“ 220°
(5) * 310° (13) «* 2200 (21) <* 2350
(6) «* 289° (14) «* 2250 (22) «« 200°
(7) «© 2950 (15) * 2000 (23) <« 2100
(8) “* 300° (16) « 210° (24) «* 2250

As no effort had been spared to secure absolute uniformity of conditions, the
conclusion seems justified that oxidation of the hydrocarbon ethylene occurs within
somewhat wide limits of temperature.

Hapt. 27—Air containing 3.1 per cent. ethylene was passed through a glass
tube containing pieces of glass tubing which had been previously ignited. No oxi-
dation occurred at the melting point of bromide of silver (427°) during four hours.

Expt. 28.—

This mixture was passed, as before, over a platinum wire and the temperature grad-
ually raised until a carbon dioxide reaction was produced. This oceurred at 240°.
The gas stream was then continued while the temperature was allowed to fall. The
lime water was repeatedly replaced, but each time became rapidly milky. Oxidation
was continuous until the temperature fell to about 110°, at which point fresh lime
water was found to remain clear. Hence, platinum having been sufficiently heated
to induce oxidation of ethylene by atmospheric oxygen, retains this power while the
temperature is lowered to a point which would have been wholly insufficient to cause
such oxidation if the temperature were rising instead of falling. This is true, more-
over, when the gas stream flows at the rate of 20 to 50 bubbles per minute; so
slowly, therefore, that there is no possibility that this effect is attributable to an

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 165

actual burning of the gas with flame. Similar results were obtained in trials with
palladium asbestos and ruthenium asbestos, and also when methane and ethane were
used.

9. PRopyLENE.—This gas was prepared by the action of potash on propyl
iodide (Hrlenmeyer, Zeitschr. f. Chem., 1864, p. 647). 80 gm. of propyl iodide
were heated with 50 gm. of potash and 50 gm. of alcohol over the water bath. The
following reaction occurs:

. ¢.H,1 +: KOH = KI -- H,0 + G.H,.

The flask containing the potash and alcohol being connected with a reversed
condenser and gently warmed, the propyl iodide is slowly added by a tap funnel, and
at a temperature of 40° the reaction begins. The gas so produced was washed with
water and digested with oil of vitriol (cold), in which it is insoluble, and finally
washed by potash solution. Propylene was also prepared from allyl iodide (Glad-
stone and Tribe, J. Ch. Soc., 1874, and also Niderist, Ann. Ch. Pharm., CXCVI,
p. 358). 20 c.c. of allyl iodide mixed with three volumes of alcohol were poured
over 30 gm. powdered zinc containing 10 gm. of mossy zinc heated in a flask over a
water bath. Powdered zine becomes during the reaction a hard, compact mass.
The addition of mossy zinc and constant agitation serve to facilitate the process. —
The reaction is as follows:

—0GH; 1 oy,

CsI + CoH OH + Zn—= Zn
The propylene so prepared was purified as in the preceding method. Careful
tests demonstrated the absence of iodine compounds from the product. Beilstein
and Wiegand (Ber., 1882, p. 1498) prepare propylene by the action of propyl alcohol
upon phosphoric anhydride. In employing this method, 120 gm. P.O; were placed
in a flask provided with a reversed condenser and propyl alcohol gradually added by
a tap funnel. The action is at first very violent and requires cooling of the flask ;
becomes less and less intense, and finally it is found necessary to heat the flask over
asbestos. After about 130 c.c. of propyl alcohol had been added the reaction ceased.
The method is satisfactory although the yield is small. A method proposed by
Klaus and Kerstein (Ber., Vol. [X, p. 695), according to which zinc dust is heated
with glycerine, was tried, but with unsatisfactory results. The intense frothing of
the mixture renders the process uncontrollable. In the various trials, propylene, as
prepared by the first three methods just described, was used. That prepared from
allyl iodide seemed to be the purest, as judged by the reactions in solution to be
detailed later.
A. P. 8.—VOL. XVII. V.

166 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Tn the oxidation experiments below cited, propylene from allyl iodide is under-
stood to have been used.
Expt. 29. Palladiwm Asbestos.—

PHOPY LEME, ase 5 bei 0ie clercrecerc cteioversyerelnicle oie <iote dete cnisi etait sieve: bicveley-sieteiste el ae eee erate che ecco tee eters 3.1

Oxidation occurred :
(1) At 170° (3) At 200°
(2) « 180° (4) « 200°
Expt. 30. Ruthenium Asbestos.—The same mixture of propylene and air was
used. Oxidation occurred :
(1) At 235° (3) At 2560
(2) «* 252° (4) « 239°
Expt. 31. Rhodium Asbestos—The same mixture of air and propylene. Oxi-
dation occurred :
(1) At 288° (3) At 270°
(2) «* 2840 (4) “ 290°
10. TRIMETHYLENE.—This very interesting hydrocarbon was obtained from tri-
methylene dibromide by the action of metallic zine (Gustavson, Ber., 1887, p. 707,
R). 20 ¢.c. trimethylene dibromide with 60 e.c. of aleohol were poured over 60 gm.
of zine dust. The reaction is as follows:

CH,Br CH,
VR

d iN
= H, + Zn=CH,—CH, + ZnBr,.

|
CH,Br

The trimethylene dibromide molecule, on losing bromine, assumes the form of a
ring and the resulting hydrocarbon is therefore a saturated compound. The gas is
evolved at a gentle heat (the temperature should not exceed 60°), and is purified by
passing through a condenser cooled by ice, by digestion with sulphuric acid and
finally by dilute permanganate of potash solution. It has been shown by Wagner
( Ber., 1888, p. 1230) that trimethylene prepared by the above reaction is liable to
contain propylene, which may be removed by prolonged contact with a weak solution
of permanganate of potash (which converts propylene into its corresponding glycol
but does not attack the trimethylene).

Hxpt. 32. Palladium Asbestos.—

Abril h {nena MI ArAr anion a nonosoaodoamasGacaphabaabtdanade acavewoscqocodonse 3.1
BY 6 ois sine oo aie ina Ss leinelealevele aus’ sate cbelavere\/ejpiets/ ope rete eterersie ale sisters Reete enone nstet crete ela st ste Detete altel eetelo te fatinta: stata = 96.9

Oxidation occurred:

(1) At 260 (2) At 290° (3) At 270°

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 167

Expt. 33. Osmium Asbestos.—The same mixture of air and trimethylene. Oxi-
dation occurred :

(1) At 200° (3) At 180°
(2) «© 200° (4) * 165°

This hydrocarbon seems to stand intermediate between propane and propylene
as regards resistance to oxidation.

11. IsopuTyLENE.—This hydrocarbon was prepared by the action of sulphuric
acid upon isobutyl alcohol, by the method of Puchot (Ber., 1883, p. 2284, R).
100 gm. isobutyl alcohol were mixed (cold) with 100 gm. oil of vitriol, 160 gm. sul-
phate of lime and 40 gm. bisulphate of potash. This mixture was heated, using a
flask with reversed condenser, to a temperature sufficient to cause a rapid evolution
of gas. Besides butyl ether and other less volatile compounds, impurities in vapor
form occur in the isobutylene resulting from this process, which is on this account
unsatisfactory. The yield is comparatively large.

By the action of potash upon isobutyl iodide a much purer product is obtained.
Isobutyl bromide may be used instead of the iodide. In either case the use of
potash in powdered form greatly facilitates the reaction. Potassium iodide, being
more soluble in alcoho] than potassium bromide, the alkyl iodide is to be preferred in |
reactions of the above type, as potassium bromide, resulting from the use of alkyl
bromides, encrusts the potash and retards the reaction.

Isobutylene prepared by the latter method was used in the following experi-
ments. It was carefully purified by digestion (cold) with sulphuric acid, and on
testing was found to be free from iodine compounds. Isobutylene is soluble in water
to a considerable extent and should therefore be collected over salt solution.

Expt. 34. Palladium Asbestos.—

Isobutylene

wr wl ss bel ae Ree oe ae <a Neg a 3.1
JG on b 3oncho0as Gatos Cag OSES OL Tan E AOONOCOLC oc Gna aU OC OCCU REE SC oSe orc amano aA Tnrrs Pome Stoke 96.9
Oxidation occurred :
(1) At 180° (3) At 170° (5) At 155°

(2) «* 160° (4) “ 185°

12. AcrTYLENE.—100 gm. crushed potash were placed in a flask connected
with reversed condenser. A mixture of 50 gm. ethylene bromide with 150 gm.
alcohol was added in small portions by a tap funnel. The escaping acetylene was
caused to bubble through boiling potash solution and then absorbed by ammoniacal
cuprous chloride solution. The resulting red precipitate was washed with ammoni-
acal copper solution, then by weak ammonia. After washing, the precipitate was
brought into a flask and decomposed by hydrochloric acid, and the acetylene thus

168 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

evolved was collected. The copper precipitate consists of Cu,C,, and. on treatment

with hydrochloric acid undergoes the reaction: rhe
CONC a 2 Tae CCL =k CE

(For an interesting description of this compound, see Keyser, Am. Chem. Jr., 1892,

p. 285.) |

The precipitate of copper acetylide must be preserved in an unoxidized state
previous to its treatment with hydrochloric acid in order to liberate acetylene. If
exposed to air during washing, the precipitate is found to remain almost unacted
upon by hydrochloric acid, and the yield of acetylene from the copper compound
will be insignificant. On this account the washing should be conducted in an atmos-
phere of carbon dioxide. ;

A very interesting method for the preparation of acetylene by the action of
water upon barium carbide has been described by Maquenne ( Compt. Rend., CXV,
p. 558). Barium carbonate is reduced by magnesium powder in presence of excess
of carbon. As the result of the somewhat violent reaction barium carbide is formed.
On moistening with water this carbide is decomposed, yielding nearly pure acetylene.

Kept. 35. Palladium Asbestos.—.

KC Ad): eee Ee ney Saar Ser oe A RAP ar SONA AeAnGr Bea oGuacoedbooopasoaeGorSoooc 3.1

Oxidation occurred:

(1) Above melting point of potassium nitrate (339°).

(Ga) 9G gs WC “« potassium chlorate (859°).
(GS) wes Og oe “ potassium nitrate (339°).
(4) “ce ce 6e “ec “ce “cc (389°).

It was found by careful tests that no CO is formed in the case of the above
mixture. In fact, no other products resulted than CO, and H,O.

Acetylene seems therefore to be more stable towards heated air in presence of
palladium asbestos than the olefines, and in this respect even to rival the paraftins.

13. Benzou.—The low boiling point of benzol and the common occurrence of
its vapor in gas mixtures justify its consideration in connection with the gaseous
hydrocarbons.

Expt. 36.—Air aspirated through benzol (prepared from benzoic acid) and
then through palladium asbestos was found to yield carbon dioxide at the following
temperatures :

(1) At’ 290° (2) At 250° (3) At 270°

Benzol vapor causes the palladium to glow very easily; in fact, much more
readily than any of the hydrocarbons heretofore tried.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 169

14. Atconot Varor.—Lxpt. 37.—Hmploying the same method detailed in the
case of benzol, oxidation was found to occur:
(1) At 160° (3) At 1500
(2) « 2400 (4) “ 150°
15. Xytous.—Very careful experiments with the vapors of meta-, para- and
ortho-xylol were tried, as it seemed possible that these three isomers might exhibit
different temperatures of oxidation dependent upon the position of the side chain.
No satisfactory results were obtained, however, on account of the want of constancy
of these hydrocarbons as regards oxidation temperature.
16. Carsonic Oxipr.—This gas was prepared by the action of sulphuric acid
upon oxalic acid. It was purified by caustic soda solution.
Kzxpt. 38. Palladium Asbestos.—

Oxidation occurred at the following temperatures :

(1) At the melting point of potassium nitrate (339°).

(2) i 6 ce ce oe (a3 66 (839°).

(3) (290°).

(4) At the melting point of potassium nitrate.

(5) Above the melting point of potassium nitrate.

(6) At the melting point of potassium chlorate (359°).

Trials were also made in varying the rate of flow, and also with different pro-
portions of carbonic oxide and air. The results did not differ materially from those
just cited. This gas seems to stand intermediate between methane and ethylene in
its resistance to oxidation.

Expt. 39. Ruthenium Asbestos.—Using the same air mixture, oxidation occurred
at the following temperatures :

(1) At 194° (3) At 1829
(2) « 209° (4) <* 188°

The preceding experiments serve to illustrate some important facts regarding
the oxidation of gaseous hydrocarbons.

1. The temperature of oxidation is mainly dependent upon the solid bodies with
which the gas is in contact—a fact which is not new.

2. Two phases are often, but not always, to be observed in the process of oxida-
tion. As the temperature rises, a point is reached at which a minute and scarcely
recognizable trace of carbon dioxide appears. After the slow oxidation has con-
tinued for some time and gradually increased during a rise of temperature of 20, 30,

170 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

or even more degrees, a sudden intense reaction occurs in the lime water, suggesting
the change from smouldering fire to actual flame. Very often this slow oxidation
is not observed and the carbon dioxide reaction occurs in the lime water suddenly
and with full intensity. The hydrocarbon molecule seems to exist at high tempera-
tures in a condition of unstable equilibrium towards oxygen. In the preceding
statements the temperatures given are those of decided and intense reaction in the
lime water. d:

3. The oxidation of a hydrocarbon by air, under conditions similar in all re-
spects, does not occur always at the same temperature. It may vary within rather
wide limits of the thermometer scale. A variation in the proportion of hydrocarbon
and air does not seem to materially influence the oxidation temperature.

4. The paraffins are the most stable towards heated air in presence of palladium.
Acetylene and carbonic oxide stand next in order. The olefines are the most easily
oxidized.

5. Of the members of the same homologous series of hydrocarbons, the lower
are the more stable towards oxidizing influences.

6. Hydrogen stands alone among combustible gases in undergoing oxidation
under the influence of palladium-coated asbestos in the cold.

7. Oxidation of gaseous hydrocarbon in excess of air involves the simultaneous
formation of CO, and H.O.

8. In all cases where air is in excess, oxidation is complete (7. e., yielding only
CO, and H,O), even though a considerable portion of the hydrocarbon may escape
unchanged. With insufficient air supply, CO, may be partly replaced by CO among
the products of oxidation.

9. As regards oxidizing power, the metals which I have studied might be
arranged in the following order, beginning with the most active: (1) Osmium,
(2) palladium, (3) platinum, ruthenium, (4) iridum, (5) rhodium, (6) gold.

Osmium is decidedly the most powerful, causing oxidation of ethylene even
below 150°. Rhodium is less efficient as regards oxidation of hydrogen than palla-
dium. Oxidizing power is apparently not dependent upon atomic weight. Of these
metals, osmium in fine division is the most easily converted into an oxide. Heated
in a flame it burns, exhibiting much the appearance of burning lamp-black, and
yields, as is well known, the volatile osmium tetroxide. At much lower temperatures
the metal is slowly oxidized and volatilized. Palladium in fine division is converted
into a stable oxide, Pd,O, on heating to redness (Wilm, Ber., 1892, p. 220). Plat-
inum and gold are not oxidizable in air at any temperature. Ruthenium oxidizes

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. aly @ |

to a sesquioxide at a red heat. Rhodium is convertible into a monoxide. In the
case of the majority of these metals, the tendency to form an unstable oxide, which
readily gives up its oxygen, explains the oxidizing power upon hydrocarbons. When
it is considered however that platinum, which induces oxidation nearly as readily as
palladium, does not produce directly an oxide when heated in air, the oxidizing

power possessed in common by these metals seems to require further explanation.
10. At a bright red heat and in excess of air, palladium asbestos causes oxida-

tion of all hydrocarbons as efficiently as does ignited oxide of copper.

11. Glowing of the palladium is by no means essential to slow oxidation where
a mere carbon dioxide reaction for the recognition of the hydrocarbon gas or vapor
is to be attained (that is, when a quantitative combustion is not aimed at).

12. The proportion of finely divided metal used upon asbestos seems to be im-
material. Palladium asbestos containing 2 per cent. of palladium is nearly as effi-
cient as that containing 30 per cent. As it is difficult to distribute the metal
uniformly on the asbestos fibre, the higher percentage, by collecting irregularly, is
more liable to cause glowing. Berliner (Ann. Phys. Chem., n. F., 35, p. 791) states
that the catalytic action of each metal, in the case of the reaction

, +0=H,0,

begins at a fixed temperature and increases with rise of temperature. The oxidation
temperature for platinum foil is about 270°; for copper, 280° ; for zinc, 350°; while
aluminium has no action at 440°. At constant temperatures the quantity of water
formed is constant. My experiments do not confirm these statements.

Krause and Meyer (Ber., 1891, p. 698, R) state that in the presence of mercury
hydrogen begins to oxidize at 305°, while increasing temperature accelerates the
oxidation. In contact with glass alone, hydrogen burns between the limits 650°
and 730°.

MIXTURES OF HYDROGEN WITH AIR AND HYDROCARBONS.

A great number of experiments have been undertaken to ascertain the influence
of hydrogen upon the oxidation of hydrocarbons in presence of metals. Of these
the following is a summary: In a mixture of methane and air, a small proportion of
hydrogen does not influence the oxidation of the methane provided the rate of flow
of the gas mixture over the palladium asbestos is very slow. Water will form
readily, but no carbon dioxide, unless the temperature rises to about the melting
point of cadmium iodide (400°), that is to say, the temperature at which the methane
would be oxidized if no hydrogen were present. If the gas mixture flows rapidly,

172 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

the burning hydrogen may so intensely heat the palladium as to cause it to glow.
This involves an immediate production of carbon dioxide. With a slow movement
of the gas, considerable volumes of hydrogen may be burned without formation of a
trace of carbon dioxide. This is the conclusion reached by Hempel; but I have
found the temperature at which the hydrocarbon is oxidized to be much higher than
he supposes (about 200°). The same statement is true of hydrogen and ethane,
and in general it may be said that the paraffins in presence of hydrogen and excess
of air only undergo oxidation by palladium asbestos when the too rapid oxidation of
the hydrogen causes glowing of the palladium.

The same general phenomena are observed in the case of mixtures of olefines
and hydrogen with air. The temperatures of oxidation of the olefines are always
lower than those of the corresponding paraffins. Below the temperature needed for
oxidation a contraction in volume often occurs, due probably to occlusion by palla-
dium. The addition of hydrogen toa mixture of air and carbon monoxide lowers
the temperature of oxidation of the carbon monoxide by palladium asbestos. While
the carbon monoxide alone in air was oxidized at temperatures above 300°, in presence
of hydrogen it may yield CO, below 100°.

As has already been stated, the slow oxidation by palladium of a hydrocarbon
in excess of air involves the conversion of carbon into carbon dioxide only, no carbon
monoxide being produced. Experiments were made with a gaseous mixture having
the following composition :

PrOPaMe <7. s.c: +: eisreceicyeroistosale eho cseueis oeiele telecine e teta eek vere ele Dorer ialpler totate ne ieisiciaiel terse teie terete oieitaketsieistelekea tareteraie 3.1
lah abxoyxD Wo oogomobs COUDO GoTo OnOONOD OCOD aD CORR DOONEUUAOOOOUOOS Sgoad AnooUesnogeorasse sdoboreS 2.
BID 6 oie ose: sia's aie dc vicie uicteueleie crelere ovels teres sfe/aleialel ofesroretoieyeteleteyatersesr cierto ietersietctetaretereratareteteteelelcietaisteteratetetetseeietetetai= 94.9

Oxidation of the paraffin occurred at temperatures varying from 270° to the melting
point of potassium nitrate (339°), but in no case was any carbon monoxide produced
nor could any olefines be detected in the gas after passing the palladium.

ACTION OF HYDROCARBONS UPON METALLIC OXIDES.

As the temperature of oxidation by air in presence of finely divided metals
seemed to vary within rather wide limits, it was possible that the differences might
be due to a lack of absolutely uniform conditions in the various trials. So much
care had been taken as regards the temperature and preparation of metal-coated
asbestos that there was no positive ground for supposing that the apparatus and
materials employed were in any way at fault.

To still further study the matter, a series of trials was made of the temperature
of reaction between reducing gases and the following compounds: Oxide of copper,

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 173

chromate of lead, oxide of silver, permanganate of silver, bichromate of silver. Only
a few of the results need be cited here. Silver bichromate heated in ethylene yielded
carbon dioxide at the following temperatures:

(1) At 8200 (4) At 2500 (8) At 280°
(2) «* 2790 (5) «© 265°
(3) * 3000 (7) * 260°

In each trial fresh silver bichromate was used. The results are, therefore, similar to
those obtained with palladium asbestos. Barely visible traces of carbon dioxide
were usually shown by the lime water in advance of the strong reaction which
occurred later. As in the case of oxidation by palladium in air, the hydrocarbon
appears to undergo a kind of “smouldering” which changes rather suddenly as the
temperature rises to a condition of much more intense oxidation.

Hempel has suggested that it might be possible, by a process of selective oxida-
tion, to remove consecutively the various constituents of a mixture of combustible
gases and in this way establish a method of analysis. The similarity in the proper-
ties of the various gases whose oxidation temperatures I have studied, towards air
and in presence of metals as well as towards silver bichromate, seems to render
doubtful the possibility of such a method. From this statement is to be excepted
the determination of hydrogen, the methods for which have been so highly perfected |
by Hempel and Winkler.

A. P. S.—VOL. XVII. W.

174 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

IT. QUALITATIVE REACTIONS OF GASES.

The recognition of any gas in a complex mixture is still a matter of difficulty in
many cases, although in a few instances methods of identification are coming to be
well known. Serious difficulties oppose all attempts at a system of qualitative anal-
ysis of gas mixtures. There are but few groups of gases (if the name “group” be
understood to include all gases chemically alike); moreover, the members of a group
exhibit much closer relationships than are to be found among the metals of any one
of the groups of Fresenius. The following classification of gases has been found
convenient for purposes of study:

Group 1. Hydrogen.

Group 2. Carbon monoxide.

Group 3. Methane, ethane, propane, the butanes, ete.

Group 4. Ethylene, propylene, trimethylene, the butylenes, ete.

Group 5. Acetylene, allylene, ete.

Group 6. Sulphur compounds: Hydrogen sulphide, methyl hydrosulphide
((CH,) SH), methyl sulphide ( (CH), 8), carbon oxysulphide (COS), carbon bisul-
phide.

Group 7. Carbon dioxide.

Unclassified: Nitrogen, oxygen.

In a study of the kind proposed, it is of importance to take into account not
only gases that are permanent under ordinary conditions but also vapors of liquids
which are liable to occur in small quantities, such as carbon bisulphide, benzol, sey-

eral of the lower paraffins and olefines, etc.

METHODS EMPLOYED.

In the case of reactions between gases and solid substances, the solid to be tried
was placed in a glass tube of one-eighth-inch diameter, which could then be heated
to any given temperature in the iron oven previously described, while the gas was
caused to stream through the tube. In the case of reactions in solution, two methods
were used.

1. The gas was caused to flow through a capillary tube into the solution con-
tained in a test-glass. The escaping gas could then be led into a second and, if
necessary, a third test-glass in order to ascertain the action of the solution used in

the first test-glass.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 175

2. The gas was collected in glass-stoppered bottles over water, a small quantity
of a solution introduced by means of a tap funnel with the lower end of its stem
bent upward, then the bottle closed and kept inverted at any given temperature for
sufficient length of time (usually from a few months to several days) to ascertain if
a reaction had occurred. The former method answers well for gases which are easily
controlled in a slow continuous stream and obtainable in large quantity. The latter
method is more economical as regards the gas to be used, and is better suited to
gases where some slight but difficultly removable impurity is suspected to occur of
a character liable to effect the reagent (such as the traces of hydrocarbons present in
hydrogen made from zine and sulphuric acid). In such cases the smaller the volume
of gas to be used in a trial the better. A reaction may usually be obtained with
from 20 to 50 c.c. of gas. Small bottles having well-ground, flat-topped glass stop-
pers answer well, as they may be kept standing inverted and may, if heat is to be
applied, be placed inverted in boiling water. It is hardly necessary to add that,
when inverted, such bottles may be used to hold gas in contact with a reagent for
long periods without danger of loss. |

HYDROGEN.

Hydrogen for the following experiments was prepared and purified as already
described (p.151). Reactions were tried in bottles and by causing the gas to bubble
through the solutions, as just detailed.

1. Reactions in Solution.
REAGENT. REACTIONS.
IPalliexchipien CnloniGls 7 6cpsansodsouor cuoU bop aUOCoaeODDOUO The solution is slowly but completely reduced, cold or at
100°. The precipitated palladium usually collects as
a black powder. Sometimes it is deposited as a film

on the glass.

Platinum chloride*......... Soodaos doonEcooT Gone OMe Very slow but complete reduction, cold or at 100°. The
reduced metal appears as a black powder.
GCroldl CONICS Ebene can Shane cce ouSaeecd one MoseABOORODE Unchanged.
SMVEP WIT accncosussoqcoondoobeacod cc seanacusdoane Unchanged if the fluid contains a trace of free nitric acid.
ASTON -GhOr wwiHEMO > occone Goudanscoeo Senocane Slowly reduced, the silver appearing as a black powder
LACH CNlONCBosaoscdcacodoocondcods opaguoaceudé.oo de Unchanged.
Innarelinnbin Mois sagocoas cooco cs suo anouaanscadnonc Unchanged.
IRONS ichen MMI NEQUE. so 5cqcococoCe co ob spodooosncpeS Slowly reduced. The orange color of the fiuid disappears
and metallic ruthenium is precipitated as a black
| powder.
Cerium dioxide dissolved in dilute sulphuric acid...... Unchanged.
Potassium permanganate,} neutral ..........-.eee see Extremely slow reduction, the purple color changing to

brown.

* Mendeleeff, Principles of Chemistry, Vol. II, p. 353.
+ Meyer and Askenasy (Ber., 1882, p. 410, R) find that electrolytic hydrogen reduces potassium permanganate.

176 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES,

Permanganate, acidulated with sulphuric acid......... Bleached slowly.

Permanivan dite) alle ins Corer teteccteteterseteletetoteiat=ietettoletetete ita Slowly changes to brown.

Potassium bichromate, acidulated with sulphuric acid.. Unchanged, cold or at 100°.

WIG TIO ONO. .Ghoaccdescosdedsosason ens wasocace Unchanged.

OSMiIC Wacid <lee ok taket ieee ionsen ernie eine ese eee eae Unchanged. Prolonged contact in bright light yields
traces of reduction after two or three weeks.

Merrie Chlovid em: <r tciel-ciselere settee erect Bocoons. Gdn Unchanged cold. Traces of reduction to ferrous chloride
after heating for several hours at 100°.

Potassium ferricyanide...... JOOROGKOOIDO GODS SOC COr Unchanged.

uthentwm\pehlonid Caecewswtsiseleeeciae eerie Unchanged. "i

INTO DOG WeleMAE > cccs5u0ssooaocopoggeoododooNSDS Unchanged.

Comments.—Russel (J. Chem. Soc., 2, Vol. XII, p. 3) states that hydrogen
reduces silver nitrate solution, nitric acid being at the same time reduced to nitrous
acid. Pellet (Compt. Rend., LXX VIII, p. 1132) finds that this reduction is due to
the silver salt containing Ag,O in excess, but that perfectly neutral silver nitrate is
not altered. Jn a series of experiments I have obtained results corroborating those
of Pellet. Silver nitrate containing a minute trace of free nitric acid is not altered
by hydrogen. If some freshiy precipitated and washed silver oxide is digested with
solution of silver nitrate, and the liquid then filtered, it will have an alkaline reaction
towards litmus and is slowly reduced by hydrogen. Boiling the solution with silver
oxide increases its alkalinity and also its sensitiveness towards hydrogen. As a
reagent for the recognition of hydrogen, it is better that the solution of silver nitrate
should be slightly basic (alkaline).

As regards the action of hydrogen upon ferric chloride, it should be said that
mere traces of ferrous chloride are produced, as indicated by a faint change of color
upon addition of potassium ferricyanide.

Free hydrogen has, therefore, a considerable reducing power for some of the
more easily reducing metallic salts, which is intensified in some cases by heating
to 160°.

It is convenient to distinguish between three classes of gas reactions as regards
intensity.

Reactions of the first class, in which a change is prompt and quantitative in its
results, e. g., when carbon dioxide is brought into contact with soda solution.

Reactions of the second class, in which a change is slow but no less complete in
a somewhat longer interval of time; e. g., the reduction of platinum chloride solution
by hydrogen.

Reactions of the third class, in which a change is not recognizable until after a
considerable interval of time, and the products appearing then are only found in
traces, such as the reduction of ferric chloride by hydrogen.

* Winkler, Zeit. Anal. Ohem., 1889, p. 269.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 177

None of the preceding reactions of hydrogen appear to fall under the first class.
Nearly all are of the second class. That reactions such as I have called the third
class should occur is difficult of explanation, and it is questionable whether a parallel
is to be found in the case of ordinary reactions of metallic salts, e. g., precipitation
of traces of ferrous sulphide in ferrous chloride solution by hydrogen sulphide, or
calcium oxalate by ammonium oxalate in dilute acid solution, where a change in
the proportion of free acid or alkali may cause the precipitation to become complete.
The reduction of ammoniacal silver solution by hydrogen cannot be materially accel-
erated by increase of ammonia or other change in the conditions, and thus remains

a typical reaction of the third class, no matter how it is carried out.

2. Reactions at High Temperatures.

The heat of formation of hydrogen chloride being high (22 calories), it seemed
probable that hydrogen should reduce the chlorides of many of the metals at mod-
erate temperatures. Small quantities of metallic chlorides were heated in a slow
current of hydrogen in a glass tube in the iron oven. The following reactions were

observed:
TEMPERATURES OF REDUCTION.

nuthenium) chloride; anbydrouss.. << -\\-s sic ose
Gold chloride (obtained by evaporation of a solution of
gold in aquaregia to dryness).

Platinum chloride (obtained by evaporation of the solu-
tion of platinum in aquaregia to dryness).

Healt ime MOTI Cxeratere\<. srsie tale! iasne wre © cislels at -\<iciclare ei ieee

SHT@P GMCS oss abodadegoopoonedddedagaadeooadKonge.

SHNIGR [OHNE ac ebocgdcnenOOAGoddede aa boogngcdE.

190°.
Not reduced at 300°.

200°.

Gave off hydrogen chloride and water at 150°. Not
reduced at 300°.

Reduced cold.

2709-2802.

330°-360°.

3509-8709.

Volatile without reduction.

. In the above experiments the hydrogen, after passing the heated metallic chlo-
ride, was conducted into dilute silver solution and the temperature observed at which
a precipitation occurred. The reduction of palladium chloride occurs at the ordi-

nary temperature.

It is an exothermic change, as the following equation shows:

2 PdCl, + 5 H = Pd,H * + 4 HCl
— (2 x 40 Cal.) + 9.4 Cal. + (4 x 22 Cal.).

Hence the heat of the completed reaction will be 17.4 calories.
If hydrogen be passed over palladium chloride contained in a glass tube, an
immediate reduction to metallic palladium occurs, attended by evolution of hydro-

*The composition of palladium hydride is probably Pd,H, according to Mendeleef, Principles of Chemistry.

Vol. I, p. 355.

178 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

chloric acid. The reaction begins and is completed without application of external
heat, the temperature of the mass becoming very high, as the above equation would
indicate. The production of hydrogen chloride in this reaction renders palladium
chloride a reagent of great sensitiveness for the recognition of free hydrogen in gas
mixtures. In order to study the reaction more fully it was necessary to prepare
pure, dry palladium chleride. When a solution of palladium in aquaregia is eyapo-
rated to dryness, brown amorphous crusts are formed which are very imperfectly
soluble in water or hydrochloric acid. Analyses were made of the compound so
obtained, but the results showed varying amounts of chlorine and it was evident
that the salt had been partially decomposed during the evaporation. In order to
obtain pure palladium chloride the following method of preparation was adopted.

Palladium dissolved in aquaregia was heated for several days in a covered
beaker over the water bath. Hydrochloric acid was added from time to time to
insure the destruction of any lower oxides of nitrogen. The solution was then
evaporated to dryness and the residue heated to 180° in a glass tube through which
a current of dry hydrogen chloride was passed. The excess of hydrogen chloride
was then expelled by a stream of carbon dioxide, and after the escaping carbon
dioxide was found to carry with it no more hydrogen chloride the compound was
considered pure. Hydrogen was now passed through the tube and into standard
soda solution. The palladium chloride was then reduced and the resulting hydrogen
chloride absorbed by the soda. The chlorine was determined volumetrically. Two
analyses were made. The results showed the salt to consist of palladium dichloride.

Experiments undertaken for the purpose of comparison of the properties of the
two preparations demonstrated that palladium chloride prepared by the method
above detailed is a much more sensitive reagent towards free hydrogen than the
compound obtained on merely evaporating to dryness a solution of palladium chlo-
ride on the water bath. So delicate is the reaction that a neutral gas, such as nitro-
gen, containing 1-20 of 1 per cent. of free hydrogen, will rapidly give an indication
when passed over the palladium chloride and into a solution of silver nitrate. It is
absolutely necessary, especially where traces of hydrogen are suspected, that the gas
should be dry, as moisture is liable to condense with the hydrogen chloride in drops,
and thus the hydrogen chloride may be prevented from reaching the silver nitrate
solution.

Ethylene reduces palladium chloride at temperatures above 100°.

The double chloride of palladium and potassium, PdCl, 2 KCl, is reduced at
about 300° by ethylene.

The hydrocarbons of crude gasolene do not reduce palladium chloride at 190°.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 179

Coal gas which had been stored under pressure in an iron cylinder, and which
had lost all its original free hydrogen, did not reduce palladium chloride at 100°.

Pure methane (prepared by Gladstone and Tribe’s method) exerted no action
until heated nearly to 250°.

Palladium chloride heated in an inert gas, such as carbon dioxide, was found to
yield chlorine at about 250°. In presence of oxygen the case is very different. Pal-
ladium chloride heated in dry air loses chlorine readily at 160°, being apparently
converted into an oxychloride. After long-continued heating to 100° in air, chlorine
in minute traces is set free and recognizable by silver nitrate containing some ferrous
sulphate.

If air containing any hydrocarbon (paraffin, olefene or acetylene) be led over
gently heated palladium chloride a decomposition occurs at once. The palladium
salt is reduced and hydrogen chloride is promptly set free. Alcohol, ether and ben-
zol vapor cause similar results. Repeated trials have shown that less than 0.1 per
cent. of hydrogen in air may be recognized by the reaction above described if the
temperature of the palladium chloride is not increased above 50° C. If the tempera-
ture rises to 100°, chlorine will be evolved from palladium chloride by the action of
air alone, as may be easily shown by causing the air to bubble through silver
nitrate solution containing a little ferrous sulphate (free chlorine is not easily
detected by silver nitrate alone, and may bubble through it unabsorbed and unrecog-
“nized).

The reduction of anhydrous ruthenium chloride by hydrogen is curiously influ-
enced by the presence of oxygen. Ruthenium chloride was reduced by pure hydro-
gen at 190°. In another experiment, using a mixture of hydrogen 4 volumes and
air 6 volumes, no hydrochloric acid was produced, even on heating to 320°. The
following is the most convenient method of applying the test:

The gas, previously dried (1) by calcium chloride and (2) by phosphoric anhy-
dride, is conducted through a narrow tube to the bottom of a dry test-tube contain-
ing about 0.2 gm. of palladium chloride. The test-tube has a rubber cork with two
holes. ‘Through a second tube the gas escapes and passes into a solution of nitrate
of silver. The test-tube may remain cold, but, in the absence of oxygen or air, it
is better to immerse in water at 40° or 50°, provided no hydrocarbons likely to reduce
palladium chloride are suspected. he palladium chloride may be placed in a glass
tube of one-eighth-inch bore, with asbestos plugs to prevent its becoming displaced
by the gas stream, and then the tube connected with the vessel containing silver
nitrate solution. If traces only of hydrogen are to be tested for, oxygen must be
completely removed by prolonged contact with pyrogallol and soda, or better with

180 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

green vitriol solution and milk of lime. The latter method for the removal of oxy-
gen is to be preferred, although the action is much slower.

Palladium oxidized by heating in air is quickly reduced by free hydrogen.

If a gas containing hydrogen is conducted over palladium oxide and then
through a narrow tube containing a very small quantity of a mixture of potassium
ferricyanide and green vitriol in fine powder, the moisture, formed in the reaction
between the hydrogen and the palladium oxide, will change the color of the powder
to blue. ;

Silver oxide is reduced by hydrogen at 100° (Darvidowa, Ber., 1888, p. 442, R).

Iodic acid is not reduced by hydrogen at 250°, ¢. ¢., at a temperature approach-
ing the point at which iodic acid dissociates (distinction between hydrogen and car-
bon monoxide).

Iridium dioxide undergoes a reduction to metal in contact with free hydrogen.
The reduction occurs in the cold and is attended with brilliant scintillations.

By employing a moisture indicator it is possible, by the help of this reagent, to
recognize minute quantities of hydrogen.

In point of delicacy the palladium chloride reaction is superior to all others.
Experiments are in hand with a view to the utilization of this reaction for the quan-
titative determination of hydrogen.

The occlusion of hydrogen by the reduced palladium and consequent loss have,
so far, prevented the use of this reaction for quantitative work.

METHANE.

Preparation—From methyl] iodide by the method of Gladstone and Tribe (see
p. 157).

Methane, the typical member of the paraffin group, is (with the possible excep-
tion of ethane) the most stable towards reagents of all hydrocarbons.

Als eederiane ain Solution.

REAGENT. REACTIONS.
Palladium chloride = .-ocsactieee eee ee eR CeCe ereer i) ;

Platinum chlorides 2s)... ccttseln ce eeren eee eee

Gold. Chloride j.:cs:.:ox7. aire rajosatee heteleloneicer ale erence emits

Silver Mitvates'scjaiseiatenowrqeretossciesetehe omelet cetereteeenee

AMMOMIAcalasilver nilrateNsjeraierenieeieaeeeeeiieneeeeeeee

The solutions of these salts are unaltered by prolonged
Rhodium chloridebs.j.:.)-, smrsvare seielsye eel rem eee | contact with methane, cold or at 100°.

See ee ee ew ee eee eee ew rae eers Feeeeeeree

Cerium dioxide dissolved in sulphuric acid
Potassium bichromate acidulated with sulphuric acid...
Mercuric chloride

ee i iy

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 181

Potassium permanganate (2 per cent. solution) is unchanged whether neutral
or acidulated by sulphuric acid.

Osmic acid is not reduced by methane in the cold.

Potassium ferricyanide is unchanged.

Peroxide of hydrogen mixed with lime water remains clear, proving that no
oxidation to carbon dioxide oceurs.

Calcium hypobromite solution remains free from any deposit of calcium car-
bonate. re

Bromine water is not discolored after prolonged contact.

Chlorine attacks methane only at a temperature considerably above 100°. A
mixture of methane and chlorine was exposed over water to bright sunlight on a
July day without undergoing any noticeable contraction in volume or change of
color (see experiments in “Chlorination of Methane” ).

Potassium rutheniate is slowly reduced with separation of metallic ruthenium.

If methane is conducted into strong sulphuric acid to which crystals of perman-
ganate have been added, immediate oxidation to carbon dioxide occurs, as proved by
the action upon lime water (in this experiment stoppers made of plaster of Paris
were used). This reaction towards permanganic anhydride is a very delicate one. _
All hydrocarbon gases yield a similar result.

2. Feactions at High Temperatures.

Ferric oxide (prepared by ignition of ferric nitrate) heated in a glass tube over
a strong Bunsen burner flame underwent very slow and incomplete reduction, some
carbon monoxide being formed in addition to carbon dioxide. Iodic acid (crystals)
is not reduced by methane on heating nearly to its temperature of dissociation (250°).
No iodine vapors and no carbon dioxide is formed. The action of methane upon the
chloride, bromide and iodide of silver was tried by the same method followed in the
case of hydrogen—these substances contained in a glass tube being heated in
methane and the gas then conducted into silver nitrate solution. The temperatures
of decomposition were as follows:

TEMPERATURE OF DECOMPOSITION,

Sil ermc hil OLIGe rence sleyetoiareiate nie nisrerieystemtcarsisratelelelereve.s ev ciere At melting point of Ba (C10), (414°).
SHINO? “RONG. Gagdogam codon cob CoScldooeiner Moorea cna Above melting point of TII (439°).
SMITE HOCH 5 o stideadadog docs Go doKouDE DO ORHaRbOROOORY Slightly volatile without reduction.

The order of reducibility by hydrogen and by methane is the same, therefore, as
in the case of the action of light, the chloride being the most easily reduced, the
iodide the most stable.

A. P. 8.—VOL. XVII. xX.

182 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Nickel chloride heated in natural gas (from Murrysville) underwent conversion
into its nearly colorless beautifully crystalline modification.

An analysis made in the laboratory by Mr. H. T. Weed showed the composition
of the salt to have been unchanged. At a dull red heat reduction occurred, with
liberation of carbon.

ETHANE.

This hydrocarbon was prepared from ethyl iodide by the process of Gladstone
and Tribe, as described on p. 159.

1. Reactions in Solution.

All the reagents used in the case of methane were tried. The reactions were
so closely similar that a detailed statement is omitted as unnecessary.

Ethane exhibits the same stability as the other paraffins towards reagents in
solution. Oil of vitriol containing erystals of potassium permanganate causes
prompt oxidation to carbon dioxide.

Potassium rutheniate is quickly reduced with separation of metallic ruthenium.

2. Reactions at High Temperatures.

Towards iodie acid, silver bichromate and the various metallic oxides, ethane
closely resembles methane in its reactions.

PROPANE.
Reactions.

Experiments with propane, made by the method of Gladstone and Tribe from
propy! iodide, led to results closely similar to those obtained with ethane and methane.
As already stated, propane is somewhat more easily oxidized than the paraffins
lower in carbon. In a series of trials, using the same reagents in solution as men-
tioned in the preceding experiments, no reactions were obtained which would serve
to distinguish between propane and methane or ethane. The results are therefore

omitted.
ISOBUTANE.

Reactions.

This hydrocarbon, prepared by the method of Gladstone and Tribe from isobuty]
iodide, was found to closely resemble the paraffins already described in its reactions.
It is characterized, however, by a lower oxidation temperature, as already stated, in
regard to the experiments with palladium asbestos.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 183

HEPTANE.

Heptane obtained from theoline (see p. 161) was found to have the same general
chemical properties as methane. Even cerium dioxide, osmic acid, gold chloride and
potassium permanganate are unaltered by prolonged contact with the liquid hydro-
carbon. Heptane seems in fact to be almost, if not quite, as stable as methane

towards reagents in solution.

The paraffins as a group are, in the main, so proof against reactions that we can
do little more than remove all other hydrocarbons by suitable reagents and then
test for paraffins by combustion over oxide of copper to carbon dioxide and water.
This, of course, leaves the nature of the individual paraffins undetermined.

‘Spongy palladium, heated in air so as to become partially converted to palla-
dium oxide and transferred to an atmosphere of methane or other paraffin, undergoes
a reduction. The reduced metal then combines with the carbon of the hydrocarbon
(Graham and Otto, Vol. III, p.995; Wilm, Ber., 1892, p. 220). This carbide heated
in air or oxygen yields carbon dioxide. The production of carbon dioxide in this
case may be utilized as a test for hydrocarbons ina gas mixture, provided no free
oxygen is present. The carbide of palladium, formed by the above method, dissolves
in aquaregia (containing but little nitric acid) with a camphor-like odor.

OLEFINES: ETHYLENE.

For preparation, see p. 161. The method of Erlenmeyer and Bunte was used.
It, is necessary for the purpose of studying its reactions to purify the gas from traces

of alcohol and ether vapor by prolonged digestion with sulphuric acid.

1. Reactions in Solution.

REAGENTS. REACTIONS.
eAMECIEh CAIONCEoosocoosocndsb09DDD OG DODDEDOONDOORE Quickly reduced, the metal appearing as a black pow-
der. No carbon dioxide is formed.
IP inn CANOMC Is vo cogoodonDAsOdsoodoNDODODSseaGooNRD Unchanged.
Goel OhlonGe sicandooasboddoncacusdoous iyo doecouoGns Extremely slow reduction, the gold appearing as a brown
‘ powder. No carbon dioxide.
Gold chloride in excess of potassium hydroxide....... Extremely slow reduction.
Iiriohweiiny TNOAGIE SG bcGgocug58505005 nbQdodoodac coon DCeKH Unchanged.
Ruthenium chloride ............... SAGO DOUOIOCNO OOOO After prolonged contact (several days) the solution is
bleached. No deposition of metal occurs.
INnoohmm Calorie. pon cousosco0. s90 BGG bobodauOd aOODNE Unchanged.
SUV ETURIINEN ALC setevetel-veleter seta eistarelole cusretels oleierats cila:slerpcre melo isi- 12 Unchanged.
Silver nitrate in ammoniacal solution............ ..-. Unchanged.

Potassium permanganate, neutral solution........... $0

Quickly turns brown.

184 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Potassium permanganate acidulated with sulphuric acid. Quickly bleached.
Potassium permanganate crystals in concentrated sul- Prompt oxidation to carbon dioxide.
phuric acid.

Potassium bichromate acidulated with sulphuric acid .. No change of color, could or at 100°.

Osmile Acide. oe scene eee eee noqogHdooaccsocONC ae Quickly reduced, with separation of metal as a black
powder.

Potassiume rutheniates. ects emereciccieciacieteiccs Quickly reduced, with separation of metal.

Merrie: Chloride sis,..tvac sastaireitaeete iste eevee miele eeeorte No change, cold or at 100°.

Calcium hypobromite containing excess of lime water. . No precipitation of calcium carbonate, and hence no
oxidation to carbon dioxide. —

I Ovassinm) ferticyanideyen eres e errr eeaeeeee Unchanged.

Bromine water...... gbodogoocdsoenNDgoOsHacoCosOCOSOS Rapid but incomplete absorption.

Peroxider ot: hydrogenrerimenecreciaue ieee eer No oxidation to carbon dioxide.

2. Reactions at High Temperatures.

Silver oxide is reduced by ethylene with simultaneous formation of silver car-
bonate at 140° (Darvidowa, Ber., 1888, p. 442, R). Palladium chloride (dry) is
reduced at about 140°. Iodic acid is reduced with liberation of iodine at about 270°.

Comments.—As is well known, bromine vapor and ethylene combine to form an
oily liquid by the reaction so characteristic of the olefine group. Winkler (Fes.
Zeitschr., 1889, p. 269) has shown that the absorption of ethylene by bromine is
incomplete, and that the contraction in yolume is by no means proportional to the
volume of the ethylene present.

I have tried experiments upon O.H, from alcohol and from ethylene dibromide
(by the action of zinc powder) and the results show that a considerable residue of
hydrocarbon remains unabsorbed after prolonged contact with bromine water in sun-
light. The residual gas, on being mixed with air and passed over ignited oxide of
copper, gave carbon dioxide and water at the outset.

The reaction between ethylene and palladium chloride in solution is of the second
class and complete, the gas being rapidly absorbed. Palladium is deposited as a
black powder, but no trace of oxidation to carbon dioxide occurs. The reaction is
almost the same in the cold and at 100°. The gas escaping from the palladium
chloride solution (after complete reduction to metallic palladium) produces no pre-
cipitate in lime water. The reaction between palladium chloride and ethylene leads
to the production of aldehyde (a study of the changes here involved is yet in hand).
Of especial interest in this connection is a statement by Berthelot, that ethylene is
oxidized to aldehyde by the action of chromic acid solution at 120° (Compt. Rend.,
Vol. CXVIII, p. 334). |

Gold chloride produces a similar result, the metal being slowly reduced. As in
the case of palladium chloride, no carbon dioxide is formed.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 185

Rhodium chloride is remarkably stable towards ethylene (and other olefines) ;
after three months’ contact with the gas, no trace of reduction was observed.

Potassium permanganate (in weak solution) has been shown by Wagner (Ber.,
Vol. X XI, p. 1230) to convert olefines on digestion (cold) into glycols. The reac-
tion may serve as a mode of preparing glycols, but could only in exceptional cases
be utilized as a gas reaction.

Chromic acid mixture is said to be reduced by ethylene (Chapman and Thorp,
Watt's Dic., 1st Supp., p. 602). In repeated experiments I have failed to show that
chromic acid undergoes reduction by ethylene. No carbon dioxide is formed, the
color of the solution remains unchanged, and no absorption occurs on prolonged
contact of ethylene with a 10 per cent. solution of chromic acid in a eudiometer.
Similar results were obtained in using potassium bichromate acidulated by sulphuric
acid. Carbon dioxide could not be detected on passing ethylene through a solution
of chromic acid at 100°.

Potassium rutheniate, an extremely sensitive reagent, loses its orange color rap-
idly and deposits metallic ruthenium.

Peroxide of hydrogen is said by Berthelot to convert ethylene into glycol. This
has apparently no significance as a gas reaction.

The reduction of palladium chloride solution, if not attended by evolution of
carbon dioxide, is an evidence of the presence of an olefine (and probably ethylene
as the commonest of the olefines) in a gas mixture.

Sulphuric acid does not absorb ethylene in the cold, but the absorption is rapid
at a temperature of 160°.

PROPYLENE.

Preparation.—F rom ally] iodide by the action of zinc (see p. 165).

1. Reactions in Solution.

Propylene, in its reactions towards the various reagents, resembles ethylene so
closely that no important differences can be mentioned.

REAGENTS. REACTIONS.

Imallleyehoren nloeG@onoaococanccsodec sdoubbacoucaod hee Reduction is prompt and complete, the gas undergoing
rapid absorption. If mixed with nitrogen (as an
inert diluent) and conducted into lime water, after
passing through the palladium chloride solution, it
is easily shown that no oxidation to carbon dioxide
is produced by the palladium chloride. The same
is true if air is used instead of nitrogen.

Platinum chloride solution ..... Stee a Soteteletelanete harevere Unchanged, cold or at 100°.

186 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Eoiel Glove Woococogndscadceatae 7400000 sielelsieielolejetetaterel> No change cold; until after prolonged contact or on
heating to 100°.

SHIGE LVRS 5 oo goacgon boone no boDN soo vodCDanGUDDDS OA Unchanged.

Silver nitrate in ammoniacal solution .............-.0. Unchanged.

iridium: chil onides: seeenereeeetenieecitcer S iste dae tetas Unchanged, cold or at 100°.

IMMINENT, CUOMO. 5 concascon codotpeoooonDDDOCAS OC Se Unchanged.

INJAOCh IN ONKOWICEs ascanacissdece Prcelelorerereeiel rene ciekerietote Unchanged.

Potassiumeriiheniaterretecttitereeiieeietiae eit ieee Traces of reduction after twenty-four hours.

Cerium dioxide in dilute sulphuric acid............... No change, cold or at 100°.

Potassium permanganate.............seceeens S0008060¢ Slowly turns brown.

Potassium permanganate acidulated with dilute sul- Quickly bleached.

phuric acid.
Potassium permanganate crystals in concentrated sul- Prompt oxidation to carbon dioxide.
phuric acid.

@hromiicraci dye rcyeiasecreevsetelleeleli aera eeesciretere Unchanged.

OMG COC, ch aadoomneauucagd aoe subsigieke ote oqeveretonetn hee et Quickly reduced, with precipitation of metal asa black
powder.

WOME ONO sooso0anccosnsns000D8000 j0d09G808S600C Unchanged, cold or at 100°.

IBYOMMIN ES “WALEL+1< cieieye chore severe tyeietaele) ciclo talon ehoretersevetoleber eretete Incomplete absorption, even after prolonged contact.

Peroxidesofehydrocentereererytiet coerce No carbon dioxide formed.

Ferricyanide of potassium ...... pono goosaooodoroeROOn Unchanged. Not reduced to ferrocyanide.

Calcium hypobromite containing excess of lime water.. Unchanged.

Propylene is not absorbed by sulphuric acid in the cold.

2. Feactions at High Tenperatures.

As regards reducing action upon metallic oxides, no important properties dis-
tinguishing propylene from ethylene can be named.

Propylene conducted over crystals of iodic acid contained in a glass tube heated
in the oven undergoes oxidation, yielding iodine vapors and carbon dioxide at a tem-
perature approximating that of dissociation of the iodic acid.

Comments.—Towards reagents in solution, propylene appears in some cases to
possess slightly greater stability than ethylene. This is especially the case with
gold chloride and potassium rutheniate. Like ethylene, it is not oxidized to carbon
dioxide by any of the reagents used in solution, with the exception of potassium
permanganate in concentrated sulphuric acid. HEXxperiments with bromine water

have led to the same results as in the case of ethylene. The absorption is decidedly
incomplete.

ISOBUTYLENE.

This gas was prepared from isobutyl iodide by the method described on p. 167.

The reactions were in the majority of cases perfectly similar to those of ethylene
and propylene.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 187

1. Reactions in Solution.

REAGENTS. REACTIONS.
Palladium Chl Once rerseeimeio se eteriehy-lrieieieielsinie me kill Quickly reduced. No carbon dioxide is formed.
Je bina OMCs Soon ocoocapaGoco»oogsabobe0 bouCUbOS Unchanged.
Gold@ehloride ere syc.c cece ie cee teinicee wisalerecieieeneasiotss Quickly reduced. No carbon dioxide is evolved in the
cold or at 100°.
Silver nitrate..... Jdbocguud uu ddousoopcdacboosuaboanaae Unchanged.
AMTMMAOA EG! GihyOe WITS coon canoe doscsugnsneouHOnoOL Unchanged.
Eurrodimmiechlori dey). iiiel-\o\selsiercialsVorel viele steel veieisiecicr=eroin)> Unchanged.
Potassium rutheniate ................ Doobodonvoounoedes Quickly reduced.
Cerium dioxide in dilute sulphuric acid............... Rapidly bleached.
Potassium permanganate, neutral................eeee0. Turns brown.
Potassium permanganate acidulated with dilute sul- Quickly bleached.
phuric acid.
Potassium permanganate crystals in concentrated sul- Prompt oxidation of the gas to carbon dioxide.
phuric acid.
CROWNS BOC! KOUIOMN So5snoooGodtodb odes dou bGanDAOde Unchanged.
OSmic acid. = ./. 22m SCS OCISO COCR Ae DO OP Se RCC Ene Quickly reduced, metallic osmium being precipitated.
IMGH®: CHOC. Sood eduqoagns nade saadnsHeaEACOnSe aor Unchanged.
HIROMI) WaALCD aie estes oslo cere teisie sielare niesieaicicly wese se sieielk oie Promptly but incompletely absorbed.
PEROIGE OF ImyGhwoyen 54500 GonpsodndousoonGs on0deo000 No formation of carbon dioxide.
AO UASSIMMMS ELL CY AMI Crete) oretoiehe <6) =I! stele els syeicleteieyeistevel~/cl eh « Unchanged.
Calcium hypobromite containing excess of lime water.. Unchanged.
Iodine dissolved in iodide of potassium solution....... Quickly bleached.
WIGREMEROUE: THENICs coadane cooooaeanOoeTeanuOboOOUDOGdD Precipitation of a gray powder which consists of (or

changes into) metallic mercury.
Sulphuric acid of 1.8 specific gravity...............00. Does not absorb isobutylene in the cold.

2. Reactions at High Temperatures.

Experiments upon the reducing action of isobutylene upon metallic oxides at
high temperatures did not develop any characteristic differences.

Iodic acid was reduced by isobutylene at 89°, with formation of carbon dioxide
and free iodine.

Comments.—Isobutylene prepared by Puchot’s method from isobutyl alcohol
causes a white precipitate in ammoniacal silver nitrate solution, while that prepared
from isobutyl iodide and potash exerts no such action.

The reaction towards mercurous nitrate (of the second class) distinguishes be-
tween isobutylene and the olefines lower in carbon. In its bleaching action upon
iodine dissolved in iodide of potassium solution, isobutylene differs from both ethy-
lene and propylene and also in the fact that it bleaches cerium dioxide in sulphuric
acid solution. It is not oxidized to carbon dioxide by any of the reagents in solu-
tion, with the exception of permanganate of potash in strong sulphuric acid.

188 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

TRIMETHY LENE.

This hydrocarbon was prepared from trimethylene bromide by the action of zine
(see p. 166). The gas was purified by sulphuric acid and by digestion with dilute
potassium permanganate solution.

1. Reactions in Solution.
REAGENTS. REACTIONS.
Palladnimlrch] onidenyeeeeeeiteetre 50056 seamen es Reduced with extreme slowness. No carbon dioxide is
formed. The reaction requires a much longer time
than in the case of the olefines proper.

Platimumichlondensy-eecseeecenerre e\ena iahere wibve.sveletetelaters Unchanged, cold or at 100°.
Goldchloride 2x. civetres meters erctsie breve ole seen ele AD AAMOSS Unchanged, cold or at 100°.
UVR SM ItLAate) creretsre/njcisiaisteraterslale eiieeetetel: Caclehterore cere ete Unchanged.
AMMOoniacalesilver MittAtellac ciel eee heee eee Unchanged.

Iridinmiyychlorid evensjeetr-eciicee ecitee eerie Unchanged, cold or at 100°.
HHO diam Chori dee eretarpereteclevoverawvelefetereiele relate teaetereiers Unchanged, cold or at 100°.
Potassium rutheniate......... save se,aets oteletalersinias- memiate sete Traces of reduction after prolonged contact (reaction of

: the third class).

Cerium dioxide dissolved in dilute sulphuric acid...... Unchanged.

Potassium permanganate, neutral...... Sobddsa520002000 Unchanged.

Potassium permanganate acidulated with dilute sul- Unchanged.

phuric acid.
Potassium permanganate crystals in sulphuric acid.... Immediate oxidation to carbon dioxide.

ChromichacidQacericciseesinceeee ere eee eerie 300006 Unchanged.

Herricuchlond ener eeereeee aeferiorer telelenete/etets sete teherteierieiers Traces of reduction to ferrous chloride after twenty-
four hours (reaction of the third class).

Bromine Waters -. istics overcome eteietotekeeielorsteretere terre Extremely slow absorption.

iPeroxidesojshy dro vente eer nee reee errs AIOdOHOCoS Unchanged.

Potassium ferricyanid ey-)jeacil)eeti eer ieeiseiteiieniacele 50 Unchanged.

Calcium hypobromite in excess of lime water......... Unchanged.

Iodine dissolved in potassium iodide solution. ........ Unchanged.

Sulphuriciacid) 128) specific eravit yee eee ree The gas is not absorbed in the cold.

2. Reactions at High Temperatures.

Iodic acid in crystals was reduced with formation of carbon dioxide at a tem-
perature closely approximating: the temperature of dissociation of the acid.

Comments.—The olefines are characterized by great stability towards oxidizing
influences at temperatures below 100°, so that carbon dioxide is not evolved except
in the case of the action of potassium permanganate in concentrated sulphuric acid.
In several cases where destructive oxidation might be expected to occur, the olefines
are converted into glycols (e. g., in the case of dilute potassium permanganate).

Trimethylene yields reactions similar to those of the true olefines but is decid-
edly more stable towards many reagents. It does not reduce osmic acid, potassium

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. — 189

permanganate or gold chloride. By these three reagents it is best distinguished from

the true olefines.

It may be mentioned that ether vapor, which so frequently contaminates the
olefines, does not reduce palladium chloride solution.

CARBONIC OXIDE.

This gas was prepared by heating a mixture of pure oxalic acid and sulphuric

acid and purified by caustic. soda solution.

1. Reactions in Solution.

REAGENTS.
alain Chloride) svete selsisicles eeie'e jc sere eisrt ale viele sisls ers

Platinum Chloride@m. sc ssisecnce sane ee CIO PROC eS rere

BO fassiumMe mu then atelerercic sve eteisrctersteleiete cieleiotare sieversisiarse ote

Cerium dioxide in dilute sulphuric acid...............
POtASST My PETMAN PANAtes am -jelelelelelselelelalsicisieias -lsieleis eee

WOM CEA CI yarereyereieielevatel ciel ets nivvetevetcisrer Pilevchatenehunchttaonniays

Osmic acid: = ie. enoracs tere avetarals elsjes\eisierese,evesvele epteverere
Ferric chloride....... Se ie raraletmiert hava seis, tsi ielerversratovaletataraG

Hydrogen peroxide..............-.. Rfetelotettotereisiie So00c¢

Po TES ISIE VOLE, SONANIG NEC

REACTIONS.

Quickly reduced, with oxidation of carbon monoxide to
carbon dioxide. The reaction is very delicate in
strongly acid solutions or in solutions of the pure,
dry chloride in water.

Carbon monoxide is oxidized to carbon dioxide, cold or
at 100°. A reduction of the platinum salt to a
lower chloride occurs, the solution assuming a
darker color. After prolonged contact (several days
or even weeks) an incomplete precipitation some-
times, but not always, occurs.

Quickly reduced to metallic gold in form of a brown
powder, the carbon monoxide being rapidly oxi-
dized to carbon dioxide, cold or at 100°.

Immediately reduced. Very delicate reaction (of the
first class).

Unchanged.

Slow reduction to metallic silver, which separates as a
black powder. The filtrate from the precipitated
silver was found to contain nitrous acid (as a result
of the action of the carbon monoxide on silver ni-
trate in ammonia) when tested by Griess’ reaction-

Slowly reduced to metal.

Unchanged cold; slowly reduced at 100° (reaction of
the third class).

Rapidly reduced. Metallic ruthenium separates as a
black powder.

Unchanged, cold or at 100°.

Quickly reduced, whether in neutral, alkaline or acid
solution.

No change of color occurs, but a trace of carbon diox-
ide is formed (reaction of the third class).

Quickly reduced.

Ferrous chloride is produced in traces after prolonged
contact.

No oxidation to carbon dioxide,

190 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

HemacyanideyOfspotassi Dal verratatcleteletet telat tetetseteleal st reraets Unchanged.
Calcium hypobromite containing excess of lime water. . Unchanged.
INDENT THITMO AOGls sooo 000099 ono DN DO anDOAONGOCODNOEE Oxidation to carbon dioxide.

2. Reactions at High Temperatures.

Todic acid in crystals is reduced by carbon monoxide, yielding carbon dioxide
and iodine vapors at 90° (De La Harpe, Pres. Zeitschr., 1889, p. 391). De La Harpe
recommends this method for the recognition of carbon monoxide in air. As higher
olefines reduce iodic acid at about the same temperature as carbon monoxide, it
would be necessary to remove them. According to my experiments, it would be
necessary also to remove acetylenes, benzol and alcohol vapors, inasmuch as these
substances exert an action similar to that of olefines. The lower paraffins are with-
out action up to temperatures at which iodic acid dissociates.

Potassium iodate in crystals is not reduced by carbon monoxide at the melting
point of barium nitrate (593°). Carbon monoxide undergoes a decomposition in
presence of certain metals at high temperatures, according to the reaction:

2C0O=C0,+ ¢.

Nickel causes such a change to occur at 350°, a very small quantity of the metal
serving to decompose a large volume of the gas (Mond. and Quincke, Chem. News,
1891, p. 108). Iron is said to cause a similar decomposition at 227° (Bell, Chemical
Phenomena of Iron Smelting, pp. 80, 7 I have made the following experiment
with palladium :

Palladium asbestos was heated in a porcelain tube in a slow stream of pure
carbon monoxide, air having been expelled from the apparatus previous to the heat-
ing by means of the carbon monoxide stream. At a moderately high temperature
(it was below redness) carbon dioxide was produced in such quantity as to cause a
strong reaction in lime water.

Carbon monoxide reduces oxide of iron at 240°, according to Bell.

Howe (ng. and Min. J., L, p. 426) states that incipient reduction of iron
oxide by carbon monoxide occurs at 141°.

The temperature of reduction of oxide of iron by carbon monoxide is unques-
tionably much lower than in the case of methane and ethane.

Carbonic oxide is absorbed by soda lime at a temperature of 200°-220°, yielding
sodium formate. Moisture promotes the reaction (Merz and Weith, Ber., 1880,
p. 718). The reaction is as follows:

NaOH + CO = HCOONa.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 191

The change is checked at higher temperatures, hydrogen being liberated at 300°.
The volatile formic acid easily liberated from the sodium formate (by decomposition
and distillation with tartaric acid) may be recognized by its reducing action upon
ammoniacal silver nitrate solution. The purest caustic soda obtainable often con-
tains substances of a reducing nature, and it is necessary to use soda free from such
impurities. If the formate of soda extracted by water from the soda lime be acidu-
lated and distilled, the formic acid obtained in the distillate may be tested for by
silver solution. .

Carbon monoxide is oxidized to carbon dioxide by steam alone, at 900° (Nau-
mann and Pistor, Ber., 1885, p. 2724).

Action of Carbon Monoxide upon Methane (Natural Glas) at High Temperatures.
According to Odling ( Watts Dic, Vol. I, p. 1111), the following reaction
occurs when methane and carbon monoxide are passed through a heated tube:
CH, + CO=H,0 + 0,5,

Natural gas from Murrysville, Pa., having the following composition, was used
in the experiment detailed below :

MVM ethan chewsveneperercharrevereectererarcuecs sak siarreies av cota ane erorey catzaus fave Lavairatavwia overcast siioke Wieigsdvate alovavaie’ basdleie.e wile ewisiescele 95.40
Caroll OX Le Meee Ppa ets ater Pe io eteti sieve cove yor ahanistave Glove oteralsl ee Botaislat ovcrotn Veiol cietievelsvaeteras ei svarateve oaretes 0.20
INET. Coe Merete areca tenors rstetererecerercterctey crete Toveiavsreue stay Pers tala cetet sete areels lorseistoteuay als, aval a wotesbis wistedsreloietise! oiaelaca;n aie 4.40

100.00

Natural gas mixed with carbon monoxide in the proper proportion (both being
carefully freed from CO.) was passed through a porcelain tube filled with bone-black
(previously purified from lime salts by muriatic acid).

The tube was heated by a coke fire with a strong draft to a temperature which
finally caused softening of the porcelain tube. The escaping gases were passed
(1) into lime water, (2) into ammoniacal cuprous chloride. No trace of a red pre-
cipitate appeared in the cuprous chloride solution such as would have formed if
acetylene had been produced. On replacing the cuprous chloride solution by bromine
water, no oily drops collected in the fluid such as would have formed if an olefine had
been produced. I have failed, therefore, to show that methane in contact with car-
bon monoxide at a high temperature gives rise to the formation of an unsaturated
hydrocarbon.

Comments.—The best reagent for the recognition of carbon monoxide is palla-
dium chloride. The reaction towards this salt in solution forms the basis of the well- °
known method for the quantitative determination of carbon monoxide. Although

192 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

slow, the reaction is extremely delicate. It is accelerated by warming to 100°.
Minute quantities of carbon monoxide in air may be recognized by the precipitation
of metallic palladium from palladium chloride solution. The precipitation often
appears in the form of a lustrous metallic film of dark brown color coating the glass.
My experiments upon the action of olefines show, however, that it is essential to the
identification of carbon monoxide that the formation of carbon dioxide by the action
of the palladium chloride be proved by means of lime water or other indicator, as
otherwise the reduction of the palladium salt may be due to a member of the olefine
group. The air may be caused to flow slowly through palladium chloride solution
and then into lime water. The tendency to undergo oxidation to carbon dioxide on
the part of carbon monoxide, and the absence of such tendency on the part of the
olefines when exposed to oxidizing influences at a temperature of 100° or below,
serves aS a most important criterion for the purpose of distinguishing between CO
and the olefine group. Winkler (fres. Zezt., 1889, p. 269) has called attention to
the value of palladium chloride as a reagent for the detection of carbon monoxide
and has made many valuable suggestions. (For a very convenient form of apparatus
for the quantitative determination of carbon monoxide by palladium chloride, see
Ellen Richards, Am. Chem. Jour., Vol. VII.)

Platinum chloride is also a valuable reagent for the detection of carbon monox-
ide. Although oxidation to carbon dioxide occurs, no metal is precipitated unless
the exposure to the gas be continued for several days, when traces of platinum
appear. The solution assumes a darker color and a partial reduction results.

Gold chloride solution is as energetic as palladium chloride in causing oxidation
of carbon monoxide.

The reduction of ammoniacal nitrate of silver solution by carbon monoxide has
been described by Berthelot (Compt. Rend., CXII, p. 597). Although chromic acid
produces minute traces of carbon dioxide at 100° when carbon monoxide is conducted
through its solution, my results do not confirm the statements of Ludwig (Ann. Ch.
Pharm., CLXII, p. 47), according to whom carbon monoxide may be determined by
oxidation to carbon dioxide caused by chromic acid solution.

The interesting compound formed by the direct union of carbon monoxide and
platinum chloride (Pullinger, J. Ch. Soc., 1891, p. 598) is not likely to prove of
importance in connection with the study of gas reactions.

Among the reactions I haye studied, the most important for distinguishing be-
tween olefines and carbon monoxide are the following:

(1) The action of palladium chloride, which in the case of carbon monoxide

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 193

yields carbon dioxide and in the case of ethylene yields no carbon dioxide. In both
cases reduction of the palladium salt occurs.

(2) Ammoniacal silver nitrate is unaltered by olefines up to and including C,
but is reduced to metallic silyer and ammonium nitrite by CO.

(3) Platinum chloride yields carbon dioxide, but is not immediately reduced to
metal by CO. With C,H, no change occurs.

(4) Rhodium chloride is slowly reduced by CO, but is unaltered by C,H,.

(5) Ruthenium chloride is bleached by carbon monoxide without reduction to
metal. Upon ethylene it exerts no action in the cold, but at 100° is slowly bleached.
No precipitation occurs in either case. Like palladium chloride, it converts ethylene
into aldehyde, especially on warming to 100°.

Among olefines, isobutylene is distinguished by its reducing action upon cerium
dioxide and by its absorption of iodine in solution, the color of the latter being
bleached.

Trimethylene, which is a saturated hydrocarbon, cannot be properly included
among olefines although isomeric with them. It is especially distinguished from
the olefines proper by its stability towards neutral potassium permanganate and
towards osmic acid. In almost all cases the reactions of trimethylene are much
slower and less complete than those of the olefines.

ACETYLENE.

This hydrocarbon was prepared by the action of alcoholic potash upon ethylene
dibromide (see p. 167). The method of preparation proposed by Berthelot (Ann. Ch.
Phys. (5) X, p. 365), by causing a Bunsen burner to “strike back,” although appli-
cable for coal gas, has not given satisfactory results when natural gas was used.

1. Reactions in Solution.
REAGENTS. REACTIONS.

all adie Chl Onid everr. sstareletester ster) cteretciatcia: sie lacie ee 0000 Reddish-brown precipitate. No reduction occurs. Very

sensitive.
latina chil orid ety yarererere srelevelare olelereisiaisainte) sisistetefeieieel acs aia Unchanged, cold or at 100°.
Goold Chloride) cris:creteractoraiz avs syetorers cis sieve lo/avevale.as/ejote eielcia c's s Immediate reduction. Intensely black precipitate of
gold. No carbon dioxide formed.
Goldichlondevinwexcess) Of potash). cle) )is-slel-lele telsi> No change cold; trace of reduction at 100°.
SHV ENTE ALE pias sae neiw te oietelelevowtciis ercesiarsls a Ones oo White precipitate. Very delicate reaction.
Ammoniacal silver nitrate......... sfolelenisisiond cats aieisvarerass White precipitate, which is so gelatinous that a 10 per

cent. solution of silver nitrate becomes nearly solid,
like boiled starch.
IbGhinin CrlOnclhs néacoonGeb bs JOG ODe ceo odan foaboones No change cold ; reduction after one week, or on boiling.
VRodiumiyehlOride ser cielelers'ele) )e1-1= steleleaisloleletsvevoveteteoToionetaT oye Unchanged.
EOLASBIUMMAECUAEINIDLE s\sjPisvcis cinicls cists cies, s /eleiere) miotole ciate ove Very slow reduction.

194

Cerium dioxide in dilute sulphuric acid...............
Potassium! permanganate merits toitetleste ele tetas
Potassium permanganate in dilute sulphuric acid......
Potassium permanganate crystals in concentrated sul-
phuric acid.
Potassium bichromate acidulated with sulphuric acid..
(OHM HOGI56 Go ancoocgaasqoboudanoopaCHooCRUOOOCGASS0¢6
Copper sulphate in neutral or ammoniacal solution....
Menrresc hil oridemeersceeneeteei ieee mrcrecie iterate soon0¢

Calcium hypobromite containing excess of lime water.

Hydrogen peroxide and lime water...... spoon 00000 30°
Bismuth pentoxide in excess of caustic potash solution
Potassiumistennicyanide santero eerie eeieercets
Iodine dissolved in potassium iodide solution..........
Yellow oxide of mercury..... BEAEOCH aOUAG Hs Od3.00 Con
WIETHTOOS. TONES on oa on oo ano agsngdduD Sooa0GeO0000005

Chromous chloride (CrCl,)................ sosyocodsodr

Mercuric chloride...... Dicdrw abate bia seca oresa rolnre sleereletareteeiae

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Slowly bleached.

Turns brown at once.

Quickly bleached.

The gas is immediately oxidized to carbon dioxide.

The color is unchanged, cold or at 100°.

Quickly reduced, turning black from precipitated metal.

Unchanged.

Decided reduction to ferrous chloride, in twenty-four
hours cold. a

Acetylene is slowly oxidized, yielding CO,, the lime
water becoming milky.

The fluid remains clear.

Unchanged.

Unchanged. The color is not bleached.

Unchanged in color.

White precipitate.

Deep red precipitate, the well-known ‘‘copper acety-
lide.”’

Is said to absorb acetylene (Roscoe and Schorlemmer,
Viol ih Pisin. 60).

White precipitate. Very delicatereaction. This reagent
converts acetylene into acetone (Ber., XVII, p. 28,
and XXI, p. 3344).

2. Reactions at High Temperatures.

Todic acid in crystals was found to be reduced by acetylene at about 90°. In
this reaction iodine vapors and carbon dioxide appeared. Aside from the experi-
ments on oxidation by finely divided metals already detailed, no other reactions at
high temperatures were tried.

Comments.—Ammoniacal cuprous chloride, the absorbent commonly recom-
mended for acetylene, although a very delicate reagent for the recognition of the
gas, is at the same time slow and its action is liable to be incomplete. A single
bubble of the gas will cause a decided red precipitate, but acetylene may be passed
slowly through a series of Woulfe bottles containing the ammoniacal cuprous
chloride solution and yet be very incompletely absorbed, so that it may still cause |
precipitation in the same reagent. The bright red precipitate dissolves easily in
hydrochloric acid, with evolution of acetylene on boiling. This affords a convenient
and well-known method for the purification of the gas. Hxposed to the air, how-
ever, the red compound changes to a deep brownish black and becomes insoluble in
acids. Consequently, in preparing and washing the red copper acetylide, with a

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 195

view to its decomposition by hydrochloric acid which liberates the pure acetylene,
great care is necessary to avoid exposure to the air (Keyser, Am. Chem. Jr., 1892,
p- 285). According to Berthelot, the copper compound is vinyl oxide in which
copper has replaced hydrogen.

H H
Cu | | Cu
NN YA |
N Va
Cc = C—O—C = C |
Ya IN
A S ;
Cu Cu (Bull Soc. Chim (2), VY, p. 191).

According to Keyser, the copper and silver compounds are Cu,C, and Ag,C,.

Silver nitrate is probably the most sensitive reagent tried. Moreover, as the
silver compound does not appear to be susceptible to oxidation, it may be used in
testing for acetylene in the presence of air or oxygen, while the copper compound,
on account of its strong tendency to undergo oxidation, is far less easily recognized
in deeply colored copper solution. Potassium permanganate in concentrated sul-
phuric acid, calcium hypobromite and osmic acid are the only reagents which cause
direct oxidation in the cold of acetylene to carbon dioxide. As an unsaturated
hydrocarbon, its indifference towards iodine solution was somewhat unexpected in
view of the avidity of isobutylene for iodine (see p. 193).

The prompt reduction of gold chloride forms a singular contrast to the indiffer-
ence of platinum chloride towards acetylene. The color of the gold when precipi-
tated by acetylene (usually blue or blue-black) is quite different from the brownish-
yellow color so often observed when gold salts are reduced.

This difference in color of the precipitated gold is probably not due to rapidity
of reduction.

ALLYLENE.

This hydrocarbon was prepared from propylene bromide by the action of alco-
holic potash. The gas resulting was washed by boiling alcoholic potash solution
and absorbed by ammoniacal cuprous chloride. The yellow precipitate resulting
was washed and afterwards decomposed by hydrochloric acid, allylene being then
set free in a pure state.

1. Reactions in Solution.
REAGENTS. REACTIONS.
leleyeliian, OmilowiGlOs5 oondadadocsndodpdasboncobode eanoe Dark-brown precipitate, which may be preserved with-
out decomposition. Closely resembles the precipi-
tate produced by acetylene.
Pian OuiloOMmel.>50 daa sts os adopeebaso0sb0Obeacebeod Unchanged.
Cle GMOs ccacobodoconpacdesnndueoodoDbo ddan Gant Slowly reduced. The color of the precipitated gold is
very dark.

196

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Silver nitrate.......... oaconnannd ApoDOUODUdUaoEOdSKCOS A 10 per cent. solution quickly coagulates to a white,
curdy mass. The precipitate dissolves on boiling or
on addition of ammonia. A very delicate reaction.

AMM OEKCRY | EMAVEP WNUK 5 Coad coop Dano angocmonne7506 Unchanged.

midramy ich OLid eayettaetey totter eee Unchanged in the cold ; at 100° iridium is precipitated.

TRA ehihen, COMO soogno50n nods soo0oNNaasonSegCDNDNRC Unchanged.

IPOS SHONEN TONING MVS 5 50 0c og0GdDoSdoK Saab DBC o0gRa0Rn Slowly reduced. Black precipitation of metallic ru-
thenium.

Cerium dioxide dissolved in dilute sulphuric acid...... Unchanged.

Potassium permanganate............. sareeotartieiehniee oeisteite

Potassium permanganate in dilute sulphuric acid,.....

Potassium permanganate crystals in concentrated sul-
phuric acid.

Quickly turns brown.
Quickly bleached.
Prompt oxidation to carbon dioxide.

Miereuric’ ChlOridere aires crore ovelersvelelereiele’ey sister ictehels tierclercieiete Dense white precipitate. Very delicate reaction.
Potassium bichromate acidulated with dilute sulphuric Unchanged in color.
acid.

OMME AGC osacocacccone000 cbasonDAC opb0 sao uODORC5 Reduced. Metallic osmium is deposited as a black
powder.

errie chloride oy.tacyieciea ects eee cieieielcoitereeeiee escent Decided reduction to ferrous chloride.

Caleium@by po brome yereretetletretttetttetsteteitelel renee Allylene is oxidized to carbon dioxide. The fluid grows
milky.

Lime water and hydrogen peroxide...............+0.. Unchanged.

Potassium ferricyanide.......... Sob dHboOONs LOUD dO000C Unchanged.

Iodine dissolved in potassium iodide solution..... dacad Unchanged.

Cuprous chloride in excess of ammonia.......... Sieteler= Canary-yellow precipitate, changing slightly to greenish
yellow on contact with air. Soluble in acids, with
liberation of allylene.

Mercurous- mitrate...cc.. ose ccek eee aeeerioceiiee none White precipitate.

2. Reactions at High Temperatures.

Experiments were tried in the reduction of certain metallic oxides, but the re-
sults are not of sufficient importance to be detailed here.

Comments.—The reactions of allylene closely resemble those of acetylene. As
regards intensity, scarcely any difference can be found. The colors of the palladium
compounds of acetylene and allylene do not differ materially. Towards ammoniacal
cuprous chloride the two gases exhibit very characteristic differences as regards the
color of the resulting compound. The copper allylide is easily soluble in dilute
hydrochloric acid. Ammoniacal silver nitrate yields a gelatinous precipitate with
acetylene but is not changed by allylene. Oxidation of allylene to carbon dioxide,
as in the case of acetylene, is not easily effected except by the most powerful oxidiz-
-ing agents, such as calcium hypobromite or potassium permanganate in concentrated
sulphuric acid. Although the allylene copper compound is rapidly formed in an
ammoniacal cuprous chloride solution, the absorption of the gas is singularly incom-

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 197

plete. Agitation with the solution is quite necessary in order to insure complete
absorption. Wagner (Ber., 1888, p. 3343) has shown that the higher acetylenes,
like the olefines, are converted by neutral potassium permanganate solution into
hydroxyl compounds.

The various classes of hydrocarbons of the fatty series possess in common a
high resistance to destructive oxidation by oxidizing agents, yielding in some cases
hydroxyl compounds but rarely CO,. This is true also of benzene, which is changed
by potassium permanganate into oxalic acid and formic acid (Bernthsen, p. 326).

SULPHUR COMPOUNDS.
CARBON OXYSULPHIDE.

This gas was prepared by the method of Klason (Ber., 1887, p. 55 R, and
J. Pr. Ch., Vol. XXXVI, p. 64). Toa cold mixture of 290 c.c. sulphuric acid and
400 ¢.c. of water, 50 c.c. of a saturated solution of sulphocyanide of potassium was
- gradually added, the mixture being warmed to 30°. The gas was evolved in a
steady stream and was purified by passage (1) through 20 per cent. potash solution,
(2) through 25 per cent. solution of aniline in alcohol, (3) through broken ice.

COS was also prepared by the action of carbon disulphide on alumina at a high
temperature (Gautier, Compt. Rend., CVII, p. 911). The gas, if dry, may be pre-
served over mercury. Contact with water causes a change into carbon dioxide and
hydrogen sulphide. Caustic soda solution is changed into a. mixture of sodium sul-
phide and carbonate. The constant tendency to decomposition renders it impossible
to preserve the gas over water without loss. In trying its reactions, it was found
necessary to conduct the gas immediately before use into some substance specially
adapted to absorb hydrogen sulphide. For the absorption of HS, Fresenius recom-
mends pumice saturated with copper sulphate solution and dried (Fresenius, Quant.
Analyse, bte Auflage). In a series of trials with this and other absorbents, precipi-
tated oxide of mercury was found to answer best. Dampened absorbent cotton is
coated with the yellow powder by rubbing with a large pestle. This preparation, used
dry in a long glass tube, completely removes H.S but exerts no action upon COS.

1. Reactions in Solution.

REAGENTS. REACTIONS. :
len lbohinimn GnOWtOsgocncasadoso0q0obdaunbodseboneboac Prompt precipitation. Precipitate is brownish black
and flocculent.
Fibra, CMOMGE: 6scadococosondbecdsoopUaDoDoLUNeac Black precipitate.
Gol dmchtorid eyes cis sesc = ele sss ve sine aictere) siclotelsitte ate) sies'oe Rapidly darkens. An olive-brown precipitate collects.
WOpPPENESU Mate rteterelelcteteciaiviey-la'e cieisicieisis\eisie nelntetalelfelotee)s Black precipitate, which forms very slowly.
Ammoniacal copper sulphate........--.eeeereeeeeeeree Black precipitate, forming promptly.

ING 1e5 Sh AOI QA

198

ArTsenious ‘Chloride. 35. .ccco as cinco ewes Geeteionte

Potassium permanganate acidulated by hydrochloric
acid.

Mercurie ‘nitrater stents cece nae ete Site stac aco eee nen neTe
Nickel@hydratesiny waters ccrrteisereicisieiattetererecestotare
Merric chlorides saci ols were cieisio ele le eee ae ot okaeteeeieite

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Voluminous, brownish black precipitate.

Prompt precipitation.

Precipitation is slow and incomplete.

Rapid and complete precipitation ; bright yellow.

Yellow precipitate, forming very slowly.

Rapidly bleached.
rium chloride, so that oxidation to sulphuric acid

The solution then precipitates ba-

has occurred. No separation of sulphur is observed.
Black precipitate.
Prompt oxidation to sulphuric acid. No sulphur is
separated.
Turns milky white and darkens gradually to black.
Darkens slowly to black.
Decided but incomplete reduction to ferrous chloride.

Potassium’ fernicyamide- se) cs se s<eci-ie SGoon sn ouas Traces of reduction to ferrocyanide.
ONE OU BaaromoariicclosciawoeoUbE de soso caTndehetooT 5 Rapidly reduced.
Potassium: rutheniate cso eer a eee 90000 Rapidly blackened.
Cerium dioxide in dilute sulphuric acid............... Rapidly bleached.
iu. ‘ These are all unchanged if dry. Sealed in a glass tube
‘ellowzoxidevtofemercuiyeneaeerceiectic carer eecnerer ;
Lith filled with the gas for two months, no change had .
itharge........ BE PICOMD BACH OBNoUnooR Tara cudoRucseaos
2 2 r occurred. If spread upon cotton, these substances
Precipitated carbonate Of copper... -. ..-. 6-2-0 ce
: | may be used to remove sulphuretted hydrogen from
Wihhite. lead £:.5i.:0.te:cveintieistoj aves esvesciore nels ayer ciewere vel eyeveinin rae eiee J 3
a mixture of the two gases.
SHINS ay UN Bn gone soodudaandedpocuuDENe DoacddcuDSUoDaGNE Is unattacked if dry; under water it is quickly black-
ened.

Comments.—Carbon oxysulphide, by reason of its ready change in presence of
water into hydrogen sulphide and carbon dioxide, gives, in the main, the reactions
of hydrogen sulphide, so that by the reagents usually employed for the detection
of the latter gas these two sulphur compounds are not distinguishable. In fact,
towards ammoniacal cadmium chloride solution, silver nitrate and palladium chlo-
ride, its reactions are characterized by somewhat greater promptness than in the
case of hydrogen sulphide. It is to be noted that, should H.S and CSO occur ina gas
mixture, the CSO would, by ordinary analytical methods, be mistaken for H.S, and
equal volumes of the two gases would yield the same weight of Ag.S, CdS, CuS, ete.

The principal metallic sulphides as usually formed by H.S could be, in many
cases, more rapidly produced by CSO; and, so far as I have been able to observe
the reactions, there is little or no tendency to separation of free sulphur such as is
common in precipitations by H,S. The absorption of CSO in ammoniacal cadmium
solution is so complete that on passing the gas through this solution none will escape
unabsorbed to cause precipitation in a second solution. An analysis seemed desira-
ble in the case of the silver compound obtained when CSO was passed through a
solution of ammoniacal silver nitrate, as the precipitate appeared much more floc-
culent and of a more brownish color than ordinary precipitated silver sulphide.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 199

Accordingly, determinations of silver and of sulphur were made with the following
results :

FOUND. CALCULATED FOR Ag,S.
qd) (2)
J STE, as GOT id ales nA ERA pec 91.15 90.95 87.06
Sabolugc SobodnosDonooonepdccs Sea cpeaeiatere 8.70 8.75 12.94
99.85 99.70 100.00

Hence the compound consisted of silver sulphide, with a small quantity of silver
thrown down by the carbon monoxide present in the gas.

Yellow mercuric oxide forms an excellent means of separation of the two gases,
and, after the removal of the hydrogen sulphide by this reagent used in a dry state,
the production of a precipitate in ammoniacal cadmium chloride solution would indi-
cate that this cadmium sulphide has been caused by carbon oxysulphide.

The presence of a little carbon monoxide in the CSO made from KCONS and
sulphuric acid is liable to mislead in the reaction towards palladium chloride, causing
a black precipitate of palladium resembling the sulphide.

METHYL HYDROSULPHIDE, (CH;) SH.

This gas may be produced by several typical reactions:
(1) When methy] chloride (bromide or iodide) is heated with KSH in alcoholic
solution, the reaction being
CH,Cl +- KSH = KCl + CH,SH.

Methyl chloride gas was conducted into a boiling alcoholic solution of KSH

perv

contained in a tube of the shape here shown.

The long limb of the tube (length, thirty inches) was connected with a reversed

200 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

condenser and was heated over a small flame. 'The gas as it escaped was passed
through a long glass tube containing cotton coated with red oxide of mercury,
which absorbs any possible traces of hydrogen sulphide and some of the mercaptan.
The gas was passed through broken ice. As the reaction above mentioned is rather
incomplete, the gas contains much unaltered methyl chloride. The same is true
when the bromide and iodide are used. Methyl chloride is the best suited to the
purpose, since it may be conducted into the liquid as a gas. The iodide, being a
very volatile liquid, is not easily added without danger of tumultuous boiling.
Formation of difficultly soluble potassium chloride or iodide causes clogging and
greatly interferes with the process, even when large delivery tubes are used.

(2) Methyl sodium sulphate and potassium hydrosulphide, on being brought
together and warmed, yield the following reaction:

NaCH,S0, + KHS = KNaSO, + CH,SH.

The reaction may be carried out in aqueous solution by the very excellent
method of Klason (Ber., 1887, p. 3407).

Klason directs as follows :

800 gm. potassium hydroxide are dissolved in water; the solution is saturated
by sulphuretted hydrogen. It is placed in a large flask and sodium methyl] sulphate,
made from 500 ¢.c. methyl alcohol, added in small portions. On gently warming, a
mixture of the vapors of (CH;).S and CH;SH is evolved. The vapors are passed
through an empty bottle and then into a second bottle containing soda solution,
which should be cooled. The methyl hydrosulphide is completely absorbed by the
soda forming NaCH,S. The sodium mercaptide so produced is very stable. Methyl
sulphide condenses to a liquid which floats on the soda solution, but does not combine
with the soda. A separation is, therefore, easily effected. The methyl sulphide may
be driven off by warming the bottle containing the soda solution, the CH,SNa being
unaffected by the heat. The methyl sulphide may thus be used in vapor form to
produce its reactions. After expulsion of the methyl sulphide, the soda solution
may be placed in a flask and decomposed by dilute sulphuric acid and CH,SH then
expelled as a gas. Some lead acetate is added to the solution in order to bind sul-
phuretted hydrogen during the decomposition of the sodium mercaptide by acid.

Klason advises a further purification; but, by the process described, the two
sulphur compounds may be obtained of sufficient purity for the study of their reac-
tions. Methyl hydrosulphide is a gas above 6° C. (Klason). It is remarkable for its
penetrating odor, which adheres most tenaciously to all surfaces, glass not excepted,
for months. All work with the gas should be done out of doors. It is somewhat
soluble in water, to which it imparts its properties.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 201

The compounds produced by the action of methyl hydrosulphide upon metallic

oxides are the true mercaptides.
results as follows:

Typical of these is the mercury mercaptide, which

HgO + 2 CH,SH = (CH,S),Hg + H,0.

The yellow lead compound is (CH;S),Pb. The copper compound is (CH,S).Cu.
The silver compound is (CHS)Ag (see Klason, loc. cit., and Richter, Org. Chem.,
trs. by Smith, p. 143). CH;SH also combines with metallic chlorides.

HgCl, + CH,SH = CH,SHgCl + HCI.

According to this reaction, numerous metallic compounds are formed. These com-

pounds change more or less readily, on exposure to air, into methyl alcohol and

metallic sulphide (Klason).

Reactions.

The vapor was caused to bubble through various solutions with the following

results:
REAGENTS,

Halladiumuerch Onid esaisercuceisciee ce ais at satel an sites wales

Platinum chloride.......... Riera halee stan Waa eh en aoe teas

herialitimp ChlOmideerera elec ccc ies ciel eee 0e ACE OD aletere

Coll GNIOTICO sed deabaatonn GOOD EDOn OE Ere ao cee Snot

Mercuri cxenlonidey cites ceistssiern cies cies sie'eieieciersicle olive ate etnies

Copper: sulphateseccrccrssomere wiotelescveiwieistelsteiovererejevaletalars olay evess

Ammoniacal copper sulphate ...............-.. SOaonOO
CUpProuseChlOridesycisiels aise1> cierelellslelelei sie Sasdudaocacadee Ac

Silver nitrates... ss ccicices ss sie Rislolois afeiataeleieleusialere everest

REACTIONS.

Cinnamon-colored, flocculent precipitate in strong or
weak solutions. Insoluble in hydrochloric acid,

nitric acid, sulphuric acid, aquaregia, ammonia and

caustic soda, in the cold or at 100°. Extremely
delicate reaction.

Yellowish-brown, flocculent precipitate in dilute or con-
centrated solution. Insoluble in the strong acids
and alkalies, and in this respect similar to the pal-
Jadium compound.

Yellow precipitate, resembling in appearance the plat-
inum compound.

Light yellow, very voluminous precipitate, changing
gradually to white as the passage of the gas is
continued, and finally redissolving to a clear solu-
tion.

White, flocculent precipitate. Darkens slightly on expos-
ure to air and light. Extremely delicate reaction.

Straw-yellow precipitate, insoluble in ammonia. Dark-
ens rapidly. Soluble in hydrochloric acid. The
hydrochloric acid solution of the precipitate con-
tains cuprous chloride.

Yellow precipitate like the preceding. Soluble in hy-
drochloric acid to cuprous salt. Rapidly darkens.

White, flocculent precipitate, changing to crystalline
needles. More stable than the preceding compound.

Yellow precipitate, resembling in appearance the cop-

Rapidly

per compound. Insoluble in ammonia.

blackens.

202
Ammoniacal: silver nitrates: .cccccss cles ssacce Beare ce

Ammoniacall cadniumechlonidesmaericcdceiee tice eee

Arsenious chloride in dilute hydrochloric acid.........

Zine sulphate in excess of caustic soda solution.......

Potassium permanganate, 6 per cent. solution acidulated
by hydrochloric acid.

Mead@acetaticns- creer ccm cle pode buds aodencaacspoos

Potassium bichromate acidulated by hydrochloric acid.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Yellow precipitate, similar in appearance and properties
to the preceding.

White precipitate in flocculent masses, somewhat solu-
ble in the reagent and in water. Permanent, if

protected from the air. By oxidation is converted
readily, in the cold, into yellow cadmium sulphide.

The fluid grows milky from floating oil drops, which
gradually collect as a very heavy oi] at bottom.

Unchanged.

Rapidly bleached. Becomes heated from the intensity
of the reaction. No sulphuric acid is produced.

Straw-yellow precipitate, insoluble in acids and alkalies.
Rapidly blackens.

Promptly reduced. to green chromic chloride. No sul-

phuric acid is produced.

BOMINE Swat elyarmetewtersicve ielteYor ee rtvevetarsreler=telere erections 5006 Rapidly bleached. No sulphuric acid is produced.

WIG HOMO S. MIMICS cooop ooc4a00000cD a nadcsDG0DOODO DROS Grayish-black precipitate.

IISA TMUTMIS cas coc anon nodes naosase sodad00000nF OOM Slowly forming black precipitate.

Nickel hydroxide in water....... Soca oDOOSengNobotaos Slowly blackens.

Ferric hydroxide in water..... bocoDODDOHNOODONS BOCS00 Unchanged.

WEION7 OFGCO OF WOH. ocuncooonocoocugnausnocooene Turns slowly gray and finally black.

IMFHS CMCC oosocoqacanscgcacagogvgcanosgsess cond Rapidly reduced to ferrous chloride. No sulphuric acid
is formed and no sulphur liberated. i

Potassium ferricyanide...... sooveadoconn 9 SsoS5anonads ' Reduced to ferrocyanide.

ORVMHNO BKC oooococcecancoooueDcDGKOGRRCS MOO OOULS BOS Rapidly blackened.

Potassium rutheniate............... Saanotoanqoossonos Extremely slow and incomplete reduction.

chy dro sens Pero xdd eerie lettered et eter No oxidation to sulphuric acid occurs.

Cerium dioxide in dilute sulphuric acid............... Quickly bleached.

itharcebandiawhitemleadtnrateryreetettetestetelere REN eiretersrerer Quickly changed, yielding a voluminous yellow powder.

Copper carbonate........... poOooSooODOERGONOOOSO RODS The resulting mercaptide is similar in appearance to
that obtained in the preceding reaction. The mer-
captides of lead and copper are very stable.

IIL VET MOM a poletelelelelelslelnl=feletslels é5od00000 ogonuscosoDoODoanE Ts not changed, dry or in water. After three months

the silver appeared slightly darkened in color.

Comments.—In the remarkable diversity of its reactions, methyl hydrosulphide

probably excels every other known gas.

The stability of many of its metallic com-

pounds is often nearly as great as that of the corresponding sulphides. The reagents
employed include many substances of high oxidizing power. It was not possible,
however, to detect in any case a trace of sulphuric acid. Under the influence of
oxidizing agents, the tendency of the mercaptans is to produce oxygen compounds,
such as the sulphonic acids.
CH,SH + 0, = CH,SO0,H.

Hence the failure to form sulphuric acid. The following experiment illustrates

the remarkable stability of methyl hydrosulphide:

The gas was passed in slow stream through a glass combustion tube containing

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 203

a fused mixture of sodium carbonate and potassium bichromate, but no sodium sul-
phate was produced. Moreover, the gas escaping from the tube possessed the char-
acteristic odor of the mercaptan. The same experiment was tried with a mixture
of sodium carbonate and sodium nitrate with a similar result. On account of its
numerous reactions towards the various metallic salts, a separation of methy] hydro-
sulphide and sulphuretted hydrogen is a difficult matter. As it acts slowly and
incompletely upon yellow mercuric oxide, this substance may be used to absorb sul-
phuretted hydrogen. Although methyl hydrosulpkide attacks and combines with
the mercuric oxide, sulphuretted hydrogen gradually expels it, the yellow color grad-
ually changing to black, owing to the formation of sulphide of mercury. The yellow
copper compound changes into copper sulphide. The same is true of the yellow
compounds of lead and silver and the white cadmium compound. This change into
sulphide is in every case promoted by exposure to air, especially in presence of
ammonia. In an aqueous solution of methyl hydrosulphide containing neither acids
nor alkalies, the various compounds are more stable.

The mercaptides are easily produced in many cases by the action of a solution
of the mercaptan in water upon the oxides, hydroxides or carbonates of the metals,
and when so formed they are easily preserved unchanged.

It is of importance to note that sulphuretted hydrogen expels methyl hydrosul-
phide from many of its metallic compounds. The reactions of CH,;SH towards gold
chloride and arsenious chloride are especially remarkable. In the former case the
production of a precipitate, gradually changing from yeliow to white and finally dis-
appearing, distinguishes this gas from sulphuretted hydrogen. The formation of an
oily liquid insoluble in water, in the case of arsenious chloride, also serves to distin-
guish between the two gases.

METHYL SULPHIDE.

This compound may be prepared by the action of methyl iodide (or, preferably,
methyl chloride) upon potassium sulphide in alcoholic solution. Gaseous methyl
chloride may be led into an alcoholic solution of potassium sulphide contained in a
flask heated over a water bath and connected with a reversed condenser. The vapor
of methyl sulphide thus formed may be freed from sulphuretted hydrogen by oxide
of mercury or by passage through warm soda solution.

In the process of Klason, already described, methyl sulphide is produced simul-
taneously with the hydrosulphide. The process yields, in fact, a larger proportion
of the former than of the latter. It may be readily separated, as already stated, by
means of soda solution, which absorbs and combines with the mercaptan but exerts

204. RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

no action upon the sulphide. On warming the soda solution, therefore, the sulphide,
condensed and floating upon its surface, may be expelled in vapor form. In the fol-
lowing experiments methyl sulphide, prepared by the action of methyl chloride upon
potassium sulphide and also by the method of Klason, was used.

Methyl sulphide is a colorless liquid, boiling at 37° C.

The compound formed by mercuric chloride with methyl sulphide is
(CH;).SHgClL. The yellow precipitate produced in platinum chloride solution is
PtS,(CH;),Cl, On standing or on warming, the powder changes to a crystalline,
isomeric form (for an important discussion of this and other alkyl sulphide com-
pounds, see Enebuske, J. Pr. Chem. (2), XX XVIII, p. 358).

- Bromine combines directly with methyl sulphide, yielding a erystallizable, vola-
tile compound, (CH;).SBr... Oxygen unites directly with methyl sulphide, yielding
(CH;).SO and (CH;).SO,, and it appears, as already stated, to be impossible to
oxidize the thioether to sulphuric acid by reagents in solution (see Richter, Organic
Chemistry, trs. by Smith).

Reactions.

In the following experiments the vapor was caused to pass into the various

solutions.
REAGENTS. REACTIONS.

Palladium chloride nettles tee ieee eerste od0¢ No change in highly dilute solution. In a 2 per cent.
solution of palladium chloride, an orange-colored, ~
pulverulent precipitate occurs, soluble on boiling.
As the solution cools, the substance is redeposited
in beautiful, orange-colored crystals. These crys-
tals are apparently monoclinic and, although none
were obtained sufficiently large for measurement,
they resemble strongly the usual forms of selenite.

Platinum chloride.............. Hoda Sno HOUR USoONNE Precipitate of a lighter yellow color than the preced-
ing. Somewhat soluble on heating, but less so than
the palladium compound. The precipitate becomes
distinctly crystalline on standing.

GoldichlomGeyrererrrccicierieuasyactettele stele tateteretetotereaccietefectatoiets Yellow precipitate, which becomes white and finally
redissolves on continuing to pass the vapor through
the solution.

Mercuric chloride......... teteleleictoteve Sociocanbopobodoos White precipitate. Very delicate reaction. When highly
magnified the precipitate is seen to consist of trans-
parent crystals, apparently monoclinic.

Copper Sulphate yai-foiote.c sv sicie/ete oisiure crore stotevelo sate rre ner rersete Unchanged.
Ammomiacalicopper, Sulphate’. <sieiste retro el eiatcreteteieiereleiete Unchanged.
SUV EN MIPTAtlen jeiere eyera 6 lots vveiaiayersfetowieieinteexdinreieictelMereneeeeee Turns brown, but little or no precipitation occurs.
ACMMONIACAlISIVER MItTAte liao cere euiastc erelermiceintelt eimeisionte Unchanged.

Cadmium chloride...... wiefetereicievercfale ele efelerettiete eleleleleietetefers Unchanged.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 205

Ammoniacal cadmium chloride .................2-.005 Very slight precipitation, which dissolves in the reagent
or in acid.

ATEEMOLS Galore soasosesosdeuesoeguue seeoreroumceysiecsretis Unchanged.

Potassium permanganate, acidulated by hydrochloric Rapidly bleached. No sulphuric acid is formed.

acid.

Meadeacetaterc bcm wi seme dace Hcinertoc eens cictos bie aioe Unchanged.

PSTOMIN CHWALET a chale jaaccsepsote Geer emn ce eos ors Ses aa Rapidly bleached. On evaporation, a crystalline residue
results. The substance is volatile in the cold.

IMFEXCUTOUSHOILTALE Aron teier ols soles ole cterelcis ae siete oiceleaeiee Very dense, grayish-black precipitate.

Nickelphydnoxidesun swatets ass sele senile 1 es este/erere Unchanged.

Ferric hydroxide in water..... Agcoosent Sonoseossopece Unchanged.

HELI C ACHIOLIGE s cr jo: aisiers/ote, «/oYora\e/areiae)s =isisvesei= Sa05nan Aga06 Decided but incomplete reduction to ferrous chloride.

Wiellow oxide of mercury in water-................-.. Unchanged.

OSTHO HOC sscansondoos sadaCoganaes Bona nese acaee Rapidly reduced.

Gtasstu Mec te nate (ayer yarela e/ ajay cpsreasiore = less eiels cre =/b/aiersie Very slowly and incompletely reduced.

CiLDOUS GhikitiGoxsecuacnduneD cacprepestoesoene anosooe White crystalline precipitate, soluble in hydrochloric
acid and reprecipitated by ammonia. Turns brown
on washing with water.

CC UPVIGAGHLOTIGE ere «1c 01s ape loioa cies aia lait ssa wel sia's sree Nese eecreiee Unchanged.

rr CHL OTIG Chreteterzseielerseisreleieis eisictoreoyarcis che le sdoconees Yellow precipitate, resembling the platinum compound.

ISVCUOSEM, YSKOGCEs sho 50cencabon0 odcsbauobaGGcueDooGe No oxidation to sulphuric acid occurs.

AOL ASSIMIM BL ELUIGV AMI Ce ei esa niacl= eleisi-ierelosleiainie sie) eis’ 6 ie Very slow reduction to ferrocyanide.

Potassium bichromate acidulated with hydrochloric acid

Very slight reduction. No sulphuric acid is formed.

Cerium dioxide dissolved in sulphuric acid............ Quickly bleached.

Precipitated carbonate of copper........-.-........--- )

ILTHDD TERS «5 coeoobodace conaCeeqadodcsuugoconboUGGOonDS | These substances, tried separately in water, remained
WIKIO GRO patedecb. stn cease DCC Heats Haan ROME ere unchanged.

LONG! GMOMIS sodossoosodagaunsacusnedoacscaaone sees |

SHIVEP LO Tin WOU oogcoecounqudocooUnoooonuoOdDOCEnS Unchanged.

Comments.—The metallic compounds of methyl sulphide are, without exception,

more soluble than those of methyl hydrosulphide.

No insoluble compounds of

methyl sulphide have yet been found. Towards oxidizing agents, methyl sulphide

is as stable as methyl hydrosulphide.

In no case was a trace of sulphuric acid

produced, although the gas was subjected to the action of many very powerful oxi-

dizing agents.

The gold chloride reaction is similar to that produced by methyl hydrosulphide.
Carbon oxysulphide is sharply distinguished from methyl sulphide and hydro-

sulphide by the ease with which it is oxidized to sulphuric acid by many oxidizing
agents, such as bromine water or potassium permanganate in acid solution; more-
over, the separation of sulphuretted hydrogen from carbon oxysulphide is easily
effected, as already stated, by the yellow oxide of mercury.
Although not altogether satisfactory, the following plan may be used to recognize
small quantities of methyl sulphide: The gas is passed through a small quantity of
A. P. S.—VOL. XVII. 2A.

206 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

weak palladium chloride solution heated nearly to 100°. On spontaneous evapora-
tion, the solution deposits monoclinic crystals easily recognized under the micro-
scope. If the mercaptan compound appears (cinnamon-colored powder) the solution
may be boiled. The methyl sulphide compound then goes into solution. The mer-
captan compound is insoluble. On evaporating the filtrate, the methyl sulphide
compound crystallizes in monoclinic prisms. If sulphuretted hydrogen and methyl
hydrosulphide are suspected to occur, these two gases may be completely absorbed
by caustic soda. The methyl sulphide is unabsorbed by soda, and by warming the
soda solution it may be prevented from condensing upon the surface of the liquid.
By using a solution of lead oxide in caustic soda, which absorbs sulphuretted hydro-
gen and methyl hydrosulphide, it is possible afterwards to expel the methyl hydro-
sulphide by cautious addition of dilute hydrochloric acid, the sulphuretted hydrogen
being then held back by the lead as lead sulphide (Klason, loc. cit.). -

Lastly, the terrible odor of the methyl hydrosulphide is sufficient for its identi-
fication under all circumstances.

NITROGEN.

Although readily prepared by the absorption of oxygen from air by pyrogallol,
the resulting nitrogen contains carbon monoxide, as shown by Tacke (Archiv. f. d.
Ges. Physiol., XX XVIII, p. 401). Ferrous sulphate in an excess of alkaline citrate
solution is unsatisfactory as an absorbent for atmospheric oxygen on account of the
extreme slowness of its action. I have found that ferrous chloride mixed with thick
milk of lime acts more rapidly for the reason that, on agitating in a glass vessel, the
pastry mass coats the walls and better exposure of the precipitated ferrous hydrate
to the air is effected. The nitrogen used in the following experiments was prepared
as described below.

Air was shaken with a mixture of pyrogallol and caustic soda solution. The
resulting impure nitrogen was caused to pass slowly through a heated combustion
tube filled partly with metallic copper (reduced by hydrogen from copper oxide) and
partly with copper oxide.

Ledue (Compt. Rend., V, CXIITI, p. 71) has shown that copper used to remove
oxygen from air should be made by the reduction of copper oxide at a low tempera-
ture, in order to avoid the formation of copper hydride and consequent contamina-
tion of the nitrogen by hydrogen. This impurity may, however, be removed by
using some copper oxide in the heated tube. It may be stated that in a series of
experiments, using pyrogallol and alkali in different proportions and in different
degrees of concentration, it was not possible to obtain pure nitrogen. In every case

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 207

the gas was found to exert a slight reducing action upon palladium chloride solution.
The compounds of nitrogen result usually by indirect processes from other com-
pounds. Additive reactions are rare.

Some interesting cases of direct union of nitrogen have been discovered by
Merz (Ber., 1891, p. 3942), who has shown that magnesium heated to redness in
nitrogen produces a nitride. The nitride so formed is stable in dry air, but yields
magnesium hydrate and ammonia in presence of moisture. So great is the affinity
of magnesium for nitrogen that, on burning in moist air, the same compound results.
The oxide formed always contains ammonia as a decomposition product of this
nitride (Aslonoglow, Chem. News, LXII, p. 99). The combination of nitrogen and
magnesium could only prove of interest as a gas reaction in case the formation of
the compound is not interfered with by the presence of such gases as are not readily
removable from a mixture. Sulphur and oxygen compounds would naturally be
decomposed by magnesium.

In experiments with natural gas, as supplied to Allegheny, in October, 1892, it
was found that magnesium heated to redness in a stream of the gas for one-half
hour yielded a strong odor and the usual reactions characteristic of ammonia on
moistening. The compound produced exhaled ammonia on exposure to air. Nitro-
gen also unites directly with lithium and potassium.

Ouvard (Compt. Rend., CXII, p. 120) obtained a nitride of lithium containing
50.28 per cent. of nitrogen.

OXYGEN.

Reactions.

The presence of oxygen in very small quantities in a gas mixture is easily
recognized by the change of color produced in a precipitate of ferrous ferrocyanide
or manganous hydroxide, or in a solution of pyrogallol in soda, or indigo solution
previously bleached by zinc dust. All of these substances absorb oxygen and at
the same time undergo a change of color. The most sensitive of these is the mix-
ture of pyrogallol and alkali. A very sensitive reagent for free oxygen is found in
precipitated manganous hydroxide in water, which, by reason of very complete
oxygen absorption, changes into Mn.0O., its color changing at the same time from
white to brown. The following process is a modification of Winkler’s method for
the determination of dissolved oxygen in water (Zeztschr. Ang. Chem., 1891, p. 105).

Two bottles of about two ounces capacity are connected as shown in the sketch.
The gas stream enters by A and bubbles through soda solution and manganous
chloride consecutively. After complete expulsion of air by the gas current, the

208 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

tube B is pushed down so that some of the soda solution is forced over into the
manganous chloride solution, causing a precipitation of manganous hydroxide. This
precipitate remains white in the absence of oxygen. If oxygen be present, it grad-
ually darkens in changing to Mn,O;. On adding now a little iodide of potassium
solution and then sulphuric acid, by the tap funnel, the oxide of manganese redis-
solves, liberating iodine, recognizable by its color even when the most minute traces
only of oxygen are present. The same apparatus can be used for pyrogallol and
soda. .

NaOH
Solutiorn

The method above described is very satisfactory in testing for oxygen in pres-

MnCl,

Soluézorn

ence of paraflins, olefines, acetylene, allylene, carbon monoxide, carbon disulphide
vapor. Sulphuretted hydrogen and carbon oxysulphide must be absorbed by ammo-
niacal cadmium chloride solution, or other suitable reagent, before the test can be
applied. If an ammoniacal cadmium chloride solution is thus used, vapors of
ammonia must be absorbed by dilute sulphurie acid before the reaction is tried. No
difficulty occurs in applying the same reaction in testing a limited volume of gas.
Instead of conducting the gas in a stream through the solutions, a eudiometer may
be used. The reaction is, however, far less satisfactory, as the solutions are liable to
hold atmospheric oxygen dissolved. By means of a standard hyposulphite solution
the free iodine may be estimated; and, as 254 parts of iodine correspond to 16 parts
of oxygen, the latter element is easily determined.

Pfordten (Fes. Zeit., 1887, p. T4) proposes the use of chromous chloride in

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 209

presence of sodium acetate for the quantitative determination (by absorption) of
oxygen ina gas mixture. According to this author, the change from colorless to
greenish blue renders the solution a suitable reagent for the recognition of oxygen.
Very minute quantities of oxygen can be detected. The preparation of the reagent
(reduction from chromic chloride by zine in presence of hydrochloric acid) is
effected in a Woulfe bottle, through which the gas is already passing, and the air
thus removed previous to the test.

’ Fuming sulphuric acid is said to dissolve oxygen (B. Lean, J. Ch. Soc., 1892,
p. 880). :

Nothing need be said here concerning the detection of oxygen when occurring
in large quantities in a gas mixture.

The general study of gas reactions has not yet attracted the attention it de-
serves. ‘The majority of articles bearing upon the subject have referred only inci-
dentally to reactions by which a particular gas, or group of gases, may be recog-
nized.

Every effort has been made to cite references to all published statements con-
cerning reactions which I have detailed. It is probable, however, that many have
been overlooked.

In conclusion, I have to express my thanks to Messrs. R. B. Carnahan, Gustav
Miller and Henry Phillips, for assistance in the work, and especially to Mr. Henry
T. Weed.

210 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Ill. SUBSTITUTION PRODUCTS OF THE ACTION OF CHLORINE UPON METHANE.

Natural gas was used in the following experiment. The gas was collected in
June, 1888, from main conveying gas directly from Murraysville to Pittsburgh. A
steel cylinder provided with thoroughly tested valves was filled from the gas main
under a pressure of eighty pounds. An.analysis of the gas showed it to have the
following composition :

Miethame) £55: sic ata SinicicvevstiaiG oserclereitale, siete sve sorsavehatstaye abotouaiere a rctetatare malta stetcreret aie oysvolevoieeereicie areata cee eet 95.40
Carbon Gioxide: 7:6 sdictcias aiciaisiece eo e\ololale, ove aveseiercisievene: + feits\e roi olatefaecets ratenetetel=renerelsns alle ieiererstaieneie ete creer 0.20
Carbon; MON ORME. 5675. scart ~are'o sleporopsteieerolelotatelelelelerereienierstel-voistaeieeinieverdetaeeiaieicion oie eieeeireeieee eters 0.
Hit Miysl@I € seroroletsievorelosevoiclo esaleve ler eferelaletorererstetetercvete(efeteteraevatste terete lane hetoteritetet tere taretete ej inte tet stele tat eters 0.
Jay ChOy<2NG FoGonanooDdGH OH OD OGD OOD GDHO CONC ObON UNDO Ud dorapeodadaddDOUs OU IeOUN tad Se OODeKaSOESae 0.
Oy GON se olaejere| = eyelaretererarclal -feleler= clever eleleltereteleketeielelecieicietisielateiatsisters oie ait iaete aes eee trace
INIGTO POM. i27~ ore sjoieic/«. siclelayoielerars aretatoasiclotelsveletetaletouctstatctetetatetotersVlacereleleterstetateterersteteiteteersteletitaieietetetcietetetarere 4,40
100.00

The following is an outline of the process of treatment:
Chlorine was generated in a large flask and washed in B before drying in
(. Natural gas was freed from carbon dioxide by caustic soda, and then dried by
sulphuric acid. Q and C served at the same time to regulate the flow. LE is a glass
combustion tube which was filled with bone-black previously washed by hydrochloric
acid. It was sought to produce the reaction :
CHa: 2Cl— OF, Cl Her

The furnace D was kept at the lowest possible temperature necessary to cause
the color of the chlorine to disappear. After passing this tube, the gases were con-
ducted through several bottles of ferrous chloride solution to remove any excess of
chlorine, as well as hydrochloric acid. A reaction occurred at once in H. The chlo-
rine disappeared. ‘Too high a temperature caused a pale flame to appear in the com-
bustion tube, which invariably led to a deposit of carbon. It was found necessary
to maintain a very low temperature in the combustion tube. Slight condensation
occurred in O of a clear liquid. Whether an excess of chlorine, or an insuflicient
quantity, or the theoretical quantity for the above reaction was used, there was formed
continuously the tetrachloride of carbon, which collected in oily drops in F and G.

From experiments in using different proportions of chlorine and methane, em-
ploying higher and lower temperatures, and when sand or asbestos was substituted
for the bone-black, and in using an empty combustion tube, I am led to the conclu-
sion that the tendency is always to form methyl chloride and carbon tetrachloride ;

Plate XXI.

Transactions Amer. Philos. Soc., Vol. XVII, Part III.

Plan of Apparatus
used in |

Chlorinating Watural Gas,

pat ry ta a
i it
t

Natural Gas

a>—$—$__——_>
Previously purifiod $y NaOH )
and dried by CaCl, . b]

Hy Ct, Sot.

FS SOs
Sol Sol, Sol.

Hz S04 : | Fe 804 R80,

‘ Sot Sod

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 211

but that the intermediate products CH.Cl, and CHCl; are only formed in relatively
small quantity.

The manufacture of chloroform from natural gas, so far as these experiments
indicate, is likely to prove of difficulty. The gas escaping from O has the odor of
methyl] chloride from methyl] alcohol, is readily soluble in water and in alcohol, and
burns with a green flame. The gas, after leaving P, passed into a solution of potas-
sium hydrosulphide in R and then on into a solution of mercuric chloride in X. An
immediate and copious precipitation occurred in X.

Methyl] chloride from methyl alcohol, as is well known, is characterized by the
property of forming a solid crystalline hydrate when conducted into icewater. The
gas, prepared by the method above described, was passed through the bottle P con-
taining broken ice while the ice was slowly melting, but no trace of a crystalline
hydrate appeared.

It was not attempted to analyze the gas, for the reason that an analysis of a
mixture of methyl chloride with some unaltered methane and traces of intermediate
chlorides would lead to very uncertain results. The odor, the solubility in alcohol,
the green color of the flame and the reaction with potassium hydrosulphide, all tend
to show that it was methyl chloride. The failure to produce the crystalline hydrate
with icewater I cannot explain.

It has long been considered a settled fact that only one methyl chloride is pos-
sible, Berthelot having shown (Ann. Ch. Pharm., CY, p. 241) that when methyl
chloride from methane and chlorine is treated with potash, saponification results with
production of methyl alcohol, just as in the case of methyl chloride from woodspirit
and hydrochloric acid.

Beyer (Ann. Ch. Pharm., CVU, p. 269, and Watts Dic., III, p. 987) states, that
methyl chloride prepared from methyl alcohol and hydrochloric acid is different from
the methyl chloride obtained by the action of chlorine on methane in the fact that
the chloride from the latter source fails to form a crystalline hydrate when led into
icewater, and that there are, therefore, two compounds isomeric, but not identical,
having the formula CH;Cl.

Roscoe and Schorlemmer (Vol. III, Pt. I, p. 203) explain the failure to form a
crystalline hydrate by the methyl chloride from methane on the ground that other
chlorinated substitution products occur with the methyl chloride. My experiments
lead me to think that this does not satisfactorily explain the difference. CH,Cl, and
CHC, do not occur except in traces in the gas which was produced, while CCl, was
easily condensed in F and G (as it boils at 78° and cannot contaminate the methyl
chloride).

212 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

The methyl chloride formed in the apparatus above described was caused to pass
through a second combustion tube heated in a furnace, and through a side tube a
stream of chlorine was passed directly into this second combustion tube. ‘The
methyl chloride supposed to have been formed by the action in the first furnace re-
ceived, therefore, an additional quantity of chlorine before passing through the com-
bustion tube in the second furnace. It seemed possible that in such a case the
formation of higher chlorinated derivatives might be better controlled taus :

CH,-22 Cl Cr Cha Her

This equation represents the reaction probably occurring in the first combustion
tube. The gases were then passed through water to remove hydrochloric acid. They
were then dried by sulphuric acid and received the additional volume of chlorine, as
above mentioned, before entering the second heated combustion tube. This reaction
might then occur:

CH,Cl-p 2Cl— CHCl, Her
In the second tube the results were hardly different from those originally obtained.
The methane tends constantly to produce methyl chloride or carbon tetrachloride,
and there is little or no probability of obtaining intermediate products except in rela-
tively very small proportions.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 213

IV. PREPARATION OF HALOGEN COMPOUNDS OF ALKYLS AND OLEFINES.

The alkyl iodides serve as the most convenient source for the preparation of the
paraffins by the Gladstone and Tribe reaction, to which reference has already been
frequently made, e. g.:

CH, 4+ Zn + H,O = Ane ae oR),
The same compounds find application in forming the olefines by the action of KOH
in alcoholic solution. Thus:
C,H,I + KOH = 6,8, + KI + HO.

The olefine dibromides are of service in the preparation of olefines by means of
zine which abstracts the halogen, liberating the olefine. The acetylenes are most
conveniently produced from the olefine dibromides, by the action of alcoholic potash,
according to the reaction:

C,H,Br, + 2 KOH = C,H, + 2 KBr ++ H,0.

Henee, the selection of convenient methods in forming these iodine and bromine
compounds has become a matter of much importance in the study of gas reactions.

The alkyl iodides are most easily formed by the action of iodine upon a mixture
of red phosphorus and alcohol.

Chancel (Ber., 1883, p. 2286 R, and Bull. Soc. Chim., XX XIX, p. 648) has given
a very convenient method for the preparation of propyl iodide and similar compounds.
127 gm. iodine, 60 gm. propyl alcohol and 10 gm. of red phosphorus are mixed in
a flask, and, after the reaction, which at once sets in, has subsided, the flask is to be
heated for an hour, connected with a reversed condenser. After cooling, the oily
liquid is decanted, washed with soda solution and dried by calcium chloride. On
distilling, nearly 90 per cent. of the theoretical yield is obtained.

This method gives very satisfactory results, and is applicable in the case of
CH,I, C.H;I, C;H.I, ete.

The process commonly recommended for the preparation of ethyl bromide by
the addition of bromine to a mixture of ethyl alcohol and red phosphorus, yields a
small and impure product and is difficult to control. Erlenmeyer (Jahresb., 1878,
p- 538) has given an excellent method for the preparation of ethyl bromide by the
distillation of a mixture of potassium bromide, sulphuric acid and alcohol. Both of
these processes yield a product largely contaminated by ether, which, although not

A. P. S.—VOL. XVIL 2B.

214 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

removable by fractionation, may be completely separated from the ethyl bromide by
digestion with sulphuric acid in the cold (as recommended by Riedel, Ber., 1891,
p. 105 R).

The olefine dibromides can be most easily prepared by the direct union of olefine
with bromine. Meyer (Ber., 1891, p. 4248) has, however, shown that in presence of
iron (wire) as an “ itbertriger,” bromine attacks ethyl bromide, producing the reaction:

C,H;Br + 2 Br = C,H,Br, + HBr. s

This process, which requires heating in sealed tubes, in the case of ethyl bromide
yields propylene dibromide in the cold from C,H,;Br. The method is open to the ob-
jection that large volumes of HBr gas are necessarily evolved. Moisture wholly
arrests the reaction. :

Experiments tried in this laboratory with other metals (palladium, magnesium,
aluminium) as “‘ bromubertriger” and at varying temperatures, have failed to give
satisfactory results in preparing ethylene dibromide. Not only heat, but pressure in
sealed tubes is also necessary.

Allyl iodide, which has served as a more conyenient material for the preparation
of propylene than propyl! iodide, was made by the action of iodine upon glycerine in
the presence of both red and yellow phosphorus, by the excellent method described —
by Behal in Ber., 1887, p. 693 R.

Jodides are to be preferred to bromides in all cases where KOH is used to pro-
duce a reaction, as KI is more soluble in alcohol than KBr. For this reason a larger
quantity of KOH is necessary for a given reaction (formation of olefine from alkyl
bromide) than in case of the iodine compound,

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 215

V. COMPOSITION OF NATURAL GAS.

The gas used in the following trials was that supplied to Allegheny by the
Allegheny Heating Company, and is the product of wells scattered over a consid-
erable gas-producing area. It may be said to represent the average composition of
an enormous volume of gas.. No important differences have been observed during
the period from 1886 to 1892 in the heating or illuminating power of the gas as
supplied to the city, except that the odor of petroleum (7. e., of higher paraffins) has
been occasionally stronger.

Tests have also been made of gas from various localities in Pennsylvania, New
York and Indiana, and Vancouver, British America, and also at Cleveland, O. In
all cases where possible the tests were made at the wells. When this could not be
done, it was necessary to use samples brought in glass vessels to the laboratory.
‘In such cases, the samples were examined for oxygen before being subjected to the
tests. As a leak in a sample vessel invariably causes an interchange of air and gas,
so that air enters in proportion as an escape of gas occurs, much dependence is to
be placed on the presence or absence of air in a gas sample as a criterion of its
purity.

HYDROGEN.

Hydrogen is almost always mentioned in the published analyses of natural gas
I have made the following chemical tests: The natural gas, as supplied to Allegheny
by the Allegheny Heating Company, was caused to flow through a solution of palla-
dium chloride for periods varying from ten days to three months. Five hundred
cubic feet have been used in a single experiment. Similar tests have been repeated
at various times between January, 1836, and May, 1892; but in no case was a trace
of precipitation observed in the palladium chloride solution. Natural gas was found
likewise to be without action upon solutions of platinum chloride and ammoniacal
silver nitrate. A stream of natural gas has been passed through dry pure palladium
chloride. This extremely delicate test has failed to show the presence of hydrogen
even in traces, although tried repeatedly during the period from January, 1886, until
May, 1892. As already stated, the results of my study of gas reactions show that
palladium chloride produces very different effects according as it is used dry or in
solution. Palladium chloride dry is reduced promptly by dry hydrogen when the
gas is used in a free state.

216 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

The same salt in solution is slowly and incompletely reduced by hydrogen,
although it is rapidly reduced by olefines and carbon monoxide. Similar tests with
palladium chloride, both dry and in solution, made at the wells, in the cases of all
the localities mentioned in the table No. I, from 1 to 14, have led to similar results.
Natural gas from Vancouver and from Kokomo, Ind., could not be tested at the
wells. Tests made in the laboratory, of the samples received from those localities,
gave the same negative results. ;

Another method of testing for hydrogen has been employed. As is well known,
a jet of hydrogen is immediately ignited by platinum asbestos. Natural gas under
similar conditions is not ignited, even when the gas jet and the platinum sponge are
mounted in an oven kept at a temperature approaching 300°. In order to ascertain
the effects of different proportions of hydrogen and natural gas, a gasometer con-
taining the gas mixture to be tried was connected with a jet in form of a drawn-out
glass tube, above which some platinum asbestos was fixed. The gas pressure could
be so regulated as to produce a pointed flame one inch long. By momentarily shut-
ting off the gas by pinching the hose, the flame could be extinguished, and the gas,.
being turned on again, played against the platinum asbestos. The length of the
flame when the gas stream from the jet was ignited was therefore a measure of the
gas flow. The gas was ignited by the platinum asbestos or not according as the
proportion of hydrogen in the natural gas was greater or less. The ignition of the
gas was also dependent upon the temperature of the oven in which the jet and the
platinum asbestos were fixed. .

Mixtures of hydrogen and natural gas produced glowing of the platinum and
ignition of the gas at the following temperatures, when the experiment was made in
a large iron oven whose temperature could be readily measured. The gas pressure
was the same in all trials.

PROPORTION OF HYDROGEN AND NATURAL GAS. TEMPERATURES OF THE OVEN AT WHICH THE GAS
INFLAMES AS IT STRIKES THE PLATINUM ASBESTOS,

Natal (838 Sei eee eee ee BD 2g 6 ig tie as fp tet ah fea Hes ete eee 40°-50<
ER CO PONS ayetarete tins ayeleiietalae merase oie ieieaiete 5

MAbaPe CBS 9 oi A 2 ee eee Ores Cece tra TEN Ser cs cots: 809-909
ERY Groene cia. te pteiel= wlolelecielelot= etetalstetetatteretey ater 2.5

Natarall B88. sis ts asic Seki Nee a ae BO eal StU sies aU RRR Ua aint ge 180°
FLY GTO POD. cle aisreleisisie caine ecaiaiter-ieieigiotstefeietatets 1

Natural (gagi cise. creremtcierelersisteineeineeretrteisiets DODO he Ne ee Ren, ee eee 9100-2200
Ely Gropen s Setetetecic'> cleieie cisis == siniei sere teinteretatcrete 0.5

Natural agreiesie. »aj0is einem olay eteyateleleieiniets Setar O93 ir AC Ree age ERE TO ES. 9'790
EDV ATOR ONG.) Soiesareiaiclclcle cleleinretatals sieieisieietstaratalets 0.25

Plire) Mattiral PAS... a..\.cismiiere wets es vin clerecelelerereteteieletniarniele/atletny eieteterasctetatete ta istetnterste tela] tiareteiereterctenetats 270°9-290°

The observed temperatures naturally vary with the pressure, size of jet, etc.,

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 217

but trials with different pressures showed greater constancy than could be antici-
pated from a method so rough in appearance. The results corroborate those
obtained by the more delicate tests. Experiments have also been tried with mix-
tures of air and natural gas which were exposed to palladium asbestos contained in
glass tubes heated in the iron oven described under “Oxidation Temperatures of
Hydrocarbons.” It has been repeatedly shown that, under such conditions, moisture
is only produced at temperatures approaching or higher than the melting point of
cadmium iodide.

_ The absence of free hydrogen has interfered with the use of natural gas in gas
engines. The prompt, sharp explosion of coal gas, so necessary for these motors,
cannot be produced in the case of natural gas which requires a higher temperature
for its ignition, and explodes with less suddenness owing to the absence of hydrogen.

The electrical devices for the igniting of coal-gas jets in dwellings by the spark
of an induction coil, have not been so successful where natural gas is used, owing to
the higher temperature of ignition of a gas consisting of paraffins and containing no
hydrogen. In laboratories where natural gas is the fuel, chemists have experienced
the inconvenience that Bunsen burners and blast lamps do not produce the high tem-
perature easily obtained when coal gas is used. Ordinary glass combustion tubing
cannot be softened by the employment of natural gas in a Berzelius blast lamp.

A coal-gas flame owes its steadiness and “ stiffness” to the hydrogen which the
gas contains. Natural-gas flames are much less steady and more easily extinguished
by air currents. ;

~ During May, 1892, a change occurred in the composition of the natural gas
supplied to Allegheny City. The gas since that time and up to November, 1892,
has been found to contain hydrocarbons which reduce dry palladium chloride. These
hydrocarbons are removed completely by digestion with fuming sulphuric acid, so
that the gas after this treatment does not reduce palladium chloride. ‘The nature of
these hydrocarbons I have been unable yet to determine.

OLEFINES.
Palladium chloride, iridium chloride, cerium dioxide in sulphuric acid, osmic
acid, all remain unchanged by natural gas, cold or at 100°. Potassium permanga-
— nate is attacked with extreme slowness.

Bromine water has been repeatedly tried. The solution was in some cases
cooled by ice to check evaporation of the bromine and in others the bromine was
added slowly, drop by drop, to compensate for its evaporation. In no case were any
oily drops produced. Prof. Sadtler, of Philadelphia, has in one instance obtained a
considerable amount of heavy oil by the action of bromine on natural gas.

218 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

My experiments seem to prove the absence of ethylene, propylene, isobutylene
and trimethylene from the gas supplied to Allegheny. The same is true of gas
from the localities mentioned in the table from No.1 to 17. Tests could not be made
at the wells in the case of gas from Kokomo, Ind., and Vancouver, British Columbia;
but samples brought to the laboratory gave similar results.

The very low illuminating power of natural gas of Western Pennsylvania is a
further evidence of the absence of olefines which, as is well known, are remarkable
for the brilliancy of the light which they produce. By the kindness of Mr. J. W.
Patterson, gas inspector of Allegheny county, Iam able to give the following data
as to illuminating power.

The gas supplied to Pittsburgh by the mains of the Philadelphia Company,
November 3034. 92, possessed an illuminating power equal to 10 84-100 candles per
five cubic feet of gas burnt per hour (mean of ten determinations).

On the same date the illuminating power of the natural gas supplied by the
People’s Natural Gas and Pipeage Company was 10 77-100 candles.

Mr. Patterson’s tests were made with a thirty-six-hole Argand burner, haying a
chimney seven inches long.

ACETYLENE AND ALLYLENE.

Palladium chloride solution is unchanged, as already stated. Cerium dioxide,
mercuric chloride, gold chloride, silver nitrate, ammoniacal cuprous chloride and —
osmic acid are all unchanged. Hence, in the gas I have tested, it may be said that
no hydrocarbons of the acetylene series occurred.

I have found no reference to acetylenes in any published analyses to which I
have had access.

CARBONIC OXIDE.

Carbonic oxide is nearly always stated to occur in the published analyses of
natural gas.

In my experiments, palladium chloride, gold chloride, silver nitrate in ammonia,
iridium chloride, rhodium chloride, osmic acid, all used in solution, were unchanged.

Experiments have been made with Allegheny City natural gas in the following
way: Gas has been caused to bubble for five weeks through ammoniacal cuprous
chloride solution. This solution was then largely diluted with water and boiled. The
gases expelled were collected and tested by palladium chloride solution ; but no car-
bon monoxide was found. It is true that, since the absorption of carbon monoxide
in cuprous chloride has been shown to be a case of mechanical solution rather than
chemical union, and that the absorbed CO can be expelled by a stream of other gases,

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 219

the use of cuprous chloride for the absorption and recognition of carbon monoxide
cannot be implicitly depended on. Still, the direct tests above named lead me to the
conclusion that no carbon monoxide occurs in our natural gas.

PARAFFINS.

_ That the lower paraffins occur in natural gas needs no proof. Methane is the
chief constituent. Small quantities of higher paraffins are usually present.

SULPHUR COMPOUNDS.

Pennsylvania natural gas does not contain recognizable quantities of either COS,
CH,SH or (CH;).S. Towards the western boundary of the State it is possible that
minute traces of sulphuretted hydrogen occur. The quantities of all such com-
‘pounds are far too small to allow of their being easily identified, even in the case of
large volumes of gas. The extreme delicacy of the reaction of methyl mercaptan
towards palladium chloride would render it possible to detect exceedingly minute
quantities of this compound should it occur.

I have not had an opportunity to test the gas from the Western Ohio territory,
which is said to contain sulphur compounds in considerable quantity.

NITROGEN.

Natural gas, dried by calcium chloride and phosphorus pentoxide, was passed
over strongly heated magnesium powder. The magnesium was partly converted
into a nitride, easily recognized by its reaction towards moisture, yielding ammonia
in considerable amount.

Repeated trials have been made of natural gas in the following way:

A measured volume of gas was passed over ignited oxide of copper contained
in a porcelain tube, the entire apparatus: having been previously filled with pure car-
bon dioxide, which was caused to flow in a continuous stream for several hours in
order to expel all traces of air. The escaping gas was collected in a eudiometer over
mercury and the carbon dioxide absorbed by soda. ‘There was left invariably a
residue of gas unabsorbed by the soda and having no action upon palladium chloride
solution. This residual gas was evidently nitrogen (see Table of Analyses). In
the gas found in an artesian boring at Middlesborough, England, nitrogen was found

in large proportion (see Table of Analyses).

OXYGEN.

By the use of pyrogallol and soda, and by the oxidation of manganous hydrate
in water, I have frequently been able to detect traces of oxygen, although on other

220 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

occasions no oxygen could be found. It has only been recognized when the gas had
bubbled continuously for many hours or days through the reagent. It cannot be
said that oxygen is a constant constituent, although it does unquestionably occur in
much of natural gas in minute traces.

CARBON DIOXIDE.

Carbon dioxide is present in all natural gas, as is easily proved by its action
upon lime water.
AMMONIA. .

In the case of a gas well near Canonsburg, the following result was obtained:
Gas was caused to bubble directly from the main at the well through water for sey-
eral hours. On applying Nestler’s reagent to the water, a feeble reaction was
obtained. Ammonia was not found elsewhere in the trials I have made.

Mr. 8. A. Ford, of the Edgar-Thompson Steel Works, reports a very interesting
case where masses of solid ammonium carbonate were blown out from a gas well by
the pressure of the gas.

Natural gas appears to consist chiefly of methane, with traces of higher hydro-
carbons of the paraffin series. Nitrogen is probably always present, together with
a little carbon dioxide. The absence of free hydrogen, of olefines and of carbon
monoxide is, I believe, clearly shown in the case of the natural gas I have examined.

If natural gas as found in the wells of any one gas region is derived from one
vast subterranean reservoir, approximate uniformity in composition should be looked
for. It is often noticed, however, that gas from adjacent wells possesses a different
odor.

A carbon dioxide determination was made in the case of samples of gas from
six wells near Tarentum, Pa. These wells were situated nearly on a straight line
less than one mile in length. The samples were all taken within an interval of three
hours.

The determinations were made by a7 per cent. soda solution in a eudiometer
over mercury.

WELL. CARBON DIOXIDE, WELL. CARBON DIOXIDE.

Nol Fecitiesteine cre cinmieiteeiteenete 0.42 per cent. IN@y LS sbGC Spaereveltainiore crcrads ietatetels 1.47 per cent.
ES, G52 Ta aterolelernieisvertaleiste etelclereitelstete 1.25 Os BONS Gdn Scoouno od sant Ibocaone 1.28 “
$6 TBS fave « sisieielsierereie’ imelaeiraeerere 0.25 << HE Ss qodsue 65 oie desis ieeiers 1.28 ss

The differences in the proportion of carbon dioxide, a constituent determinable
with great precision, would be difficult to explain if the gas flowing from these dif-
ferent wells is derived from one subterranean reservoir, .

Plate XXII.

Transactions Amer. Philos. Soc, Vol. XVII, Part II.

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RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 221

VI. QUANTITATIVE ANALYSIS OF NATURAL GAS.

It is not possible to determine the proportion of the individual paraffins in a gas
mixture by the Bunsen method of explosion of oxygen unless it can be positively
asserted that only two paraffins occur. This may be readily shown by an example.
If a mixture of one volume each of marsh gas, ethane and propane is burnt, the vol-
umes of oxygen required, carbon dioxide and steam produced will be as follows:

OXYGEN REQUIRED. CO,. H,O VAPOR.

Levol, methane... ../- ds Codobson HOCUS een ASE CUD EME OUUROOE 2 vols. 1 vol. 2 vols.

il “9 GURRPG nossa coonioconsdeduse dn uscacubeousobDEauce 33‘ ee By ace

Ul ¢o DIGI cecouoansnécc basocudeeognpoesatonpoAcadt Diora: one Ais &
105 « 6 « lope:

Three volumes of ethane require for combustion ten and one-half volumes of
oxygen, and yield six volumes CO, and nine volumes of steam.

Hence a mixture of three gaseous paraffins could not be distinguished, in the
case of a volumetric analysis, from the intermediate paraffin. Moreover, the heat of
combustion of three volumes of the intermediate paraffin is almost exactly equal to
that of a mixture of one volume each of the three.

From the fact last stated it follows that, as regards the calorific value of a mix-
ture of paraffins, an exact determination of the character of the individual paraffins
is not required.

A saving of time, the possibility of using a larger volume of gas, the avoidance
of a volumetric determination of water vapor, are some of the advantages gained by
a combustion over copper oxide.

The application of gravimetric methods for the examination of gas is not new.
Winkler (Handbook of Technical Gas Analysis, p. 87) has described such a process
for the analysis of mine gas. —

Description of Method.—The process employed was, with some slight modifica-
tions, the same as described in the Annual Report of the Geological Survey of
Pennsylvania for 1886.

Glass cylinders having stop-cocks at both ends, accurately calibrated by mer-
cury and of 300-400 c.c. capacity, were filled with natural gas. Where possible,
this was done at the well. Before filling with gas, finely drawn-out threads of
glacial phosphoric acid were inserted through the stop-cock into the vessel. After
twenty-four hours the gas sample could be considered dry.

Glacial phosphoric acid, on softening in the flame, may be readily drawn out

A. P. 8.—VOL. XVII. 20.

222, RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

like glass into rods of almost hairlike fineness. The quantity required was not suffi-
cient to cause error in the gas measurements, inasmuch as the gas, as it flows from
the wells, is in most instances remarkably dry.

The cylinder was then connected with a porcelain combustion tube, C, contain-
ing copper oxide. The general arrangement of the apparatus is shown in the accom-
panying sketch. |

Before the communication was made between the tube C and the glass cylin-
der A, air was expelled from C by pure nitrogen dried in the tubes M. The com-
bustion tube was intensely heated during the passage of the nitrogen.

After expulsion of air by nitrogen, the natural gas was caused to flow over the
copper oxide previously heated for some time. The movement of the gas through
the combustion tube was controlled by means of mercury, which flowed from the
funnel D into the gas cylinder, and was so regulated that two hours were required
for complete combustion.

Experiments showed that there is no danger of production of carbon monoxide
or unsaturated hydrocarbons when the gas stream is slow.

After the gas had been expelled from the cylinder A, it was rinsed by lowering
the mercury funnel so that nitrogen passed down into the cylinder, to be again driven
out by raising the funnel.

After the gas had been fully burnt, air (purified by the lower system of drying
tubes in the sketch) was passed through the apparatus till the nitrogen and moisture
had been fully displaced and the process was then complete, the CO, and H,O being
determined by weight. The method, as is seen, gives merely the proportions of car-
bon and hydrogen. |

As the exact percentage of the paraffins in the gas mixture cannot be ascer-
tained by analysis, an approximation alone is possible.

The composition by weight of some of the lower (gaseous) paraffins is as follows:

PARAFFINS. CARBON, HYDROGEN.
Meth ames sajarc ois amiereins vioiata sieteleueneiernlets! sacar oie teletoetcie shisinre re tareaterel cietete 74,97 per cent. 25.03 per cent.
TYG ATC sy cfo\c\oc-2s1>\ aye fopsrn’ fons ole ofacelloventatetpiaaavaleistctopirialeietelaieetstioleter eet tee tarete 19. 96 ae 20.04 <
IDO OING aoandsogooogadooccdaes afolelefeiesehelsfo(eratelatein siclelecoletnieleleaeieteiatensiers SiS ame LeIea) eo
Bit rerierelereretereveroreveloleresteleltnfeteiche sratalstcietetsisrel- tater spalsheraatalsioterafeeiteae ofc eee ORaheienee LGE28 F=-'<*

In the following table, the calculated composition by weight of various mixtures
of methane and ethane is given (the atomic weight of carbon being 11.97):

MIXTURE OF

METHANE. ETHANE. CARBON. HYDROGEN.
1 vol. AL WO] Siasere ore iolui)eraiciepenatepote epsiararonecerareteintrerehetercreke feteteter siete tetets 78.22 per cent. 21.78 per cent.
Bees i sin cin eins oiwjviejefosatelayeln/aratevclase,aiefatole/atuteueteletetaiererdetateiststetats LELETG Is OU 22.27 =

ees NE AEGS Hab, wv sheielytareinete! de visipiale,b eleisielelv estate o/tis Shevipe te ceanen Glace meme a2.62 <

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 223

5 vols aN, Sealetayaietareenretottetotatekal teat- pateial dete agai cialotatenal eletctetarei alepaisep me 77.11 per cent. 22.89 per cent.
oe ft IL aR Boot SUDO E G0 JUC Ca AMOI LOM EIGER AODIGOn ma CACAO Uo) San <6
Uh ost MON ONG BIBS HOB BE Enon BE COORG DEUCSpEs rho oaoe 16.00) = <6 23.30 “
te 1 oe Ad OG OLE COLE OBO GC COCR OO CET SMOMinci Anos aaObdC (RO a 23.44 “«
Tye Mgt ASUS rare cnsciar se treicioke Tera slows oleae a ae eis wie mise eames HAG) = PY (Ve eG
Ges: Lei ceietafaietatetaiciotelwrslelelclaieicieisierels ole Weraptstel en aistere inte eee eae T(dsttaye 9G 23.86 <<

os Dee Marae ervete heir toto tea lasevole piniel pisses hip al oleis:euige iste ees lSS 75.82 « PEAS: «5

From a gravimetric analysis of natural gas, it is easy to determine the relative
proportions by weight of carbon and hydrogen in unit volume, and from these the
composition may be stated volumetrically in terms of ethane and methane, by the
use of the preceding table, and with a fair approximation to the truth.

It is probable that minute quantities of propane and perhaps higher paraffins
occur, but these cannot be identified. The nitrogen and carbon dioxide being deter-
mined, the yolume of

CiEnSe (CHER ENON ls Gea tie
is obtained as a difference. The error involved in such a method may then be
exactly defined as follows :

The hydrocarbons may consist of methane with traces of propane or of methane
with ethane or butane, but the analysis will be stated volumetrically in terms of
methane and ethane only.

As regards the question of fuel value, I have endeavored to show (see Report
of Geol. Survey of Penna. for 1886) that the above method will give closely approx-
imate results when certain factors relating to available heat of combustion of par-
affins are used.

The gravimetric method affords at the same time a means of control, for it is not
only true that in a given volume of a particular paraffin, or of a mixture of paraffins,
the hydrogen and carbon will occur in definite quantity, but the ratio © is a constant
and will be greater as the proportion of higher to lower paraffins is greater.

These considerations will serve to show the limits of accuracy of the method.

Nitrogen was determined by passing a measured volume (100 c.c.) over ignited
copper oxide contained in a porcelain tube, and then into a eudiometer containing
soda solution. By means of a stream of carbon dioxide continued for several hours,
the air was expelled from the apparatus previous to the combustion of the gas. In
presence of large excess of carbon dioxide, combustion by copper oxide is greatly
retarded, and the process must be conducted very slowly to effect complete oxidation.

Oxygen, as already stated, occurred in too small proportion to allow of a quan-
titative determination.

Carbon dioxide was determined by soda solution in a eudiometer over a mercury
trough.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

224

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RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 225

Vil. ORIGIN OF NATURAL GAS AND PETROLEUM.

Soon after the early discoveries of oil and gas in Pennsylvania, the geologists
proposed a hypothesis to account for the origin of these remarkable substances.

Remains of the marine vegetation of the Devonian inland sea, as they were grad-
ually buried under the later accumulations of sediment and exposed to gentle heat
from below, underwent a slow process of destructive distillation. In this way, all
the varieties of petroleum and natural gas were produced. This view, adopted from
a purely geological standpoint, seemed so plausible that for a long period no other
was thought of. Mr. J. F. Carll, of the Second Geological Survey of Pennsylvania,
has discussed the hypothesis very exhaustively in his various official reports. If
this view is correct, oil and gas are probably stored products, and are not being con-
tinuously generated at the present time.

Opposed to this view is the more strictly chemical hypothesis of Mendeléeff, who,
in 1876, expressed his belief that petroleum and gas are of igneous origin.

On account of the high value assigned by astronomers for the mean density of .
the earth as compared with that of the surface rocks, it follows that the heavy metals
are mainly accumulated at great depths where a temperature of fusion may be as-
sumed. Many of these metals combine readily with carbon to form carbides. Iron,
in form of a carbide, when exposed to steam at high temperatures, is rapidly oxidized,
the hydrogen of the water then combining with the carbon set free and producing
hydrocarbons.

Citing experiments of Cloez, who produced mixtures of hydrocarbon oils by
the action of hydrochloric acid upon ferromanganese, Mendeléeff concluded that such
reactions have occurred at great depths below the earth’s surface by the contact of
steam with incandescent metallic carbides.

“During the upheaval of mountain ranges, crevices would be formed at the
peaks with openings upward, and at the foot of the mountains with openings down-
ward. ‘Thus there was opportunity for the water to penetrate to great depths and for
the hydrocarbons to escape. The situation of naphtha at the foot of mountain chains
is the chief argument in my hypothesis” (Mendeléeff, Principles of Chemistry,
Vol. I, p. 365).

| According to this view, oil and gas are being contynuously generated, for there is
no reason to suppose that the masses of metallic carbides in the earth’s interior are
exhausted ; such, in fact, seems to be Mendeléeff’s view.

226 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Mendeléeff points especially to the absence of large quantities of nitrogen com-
pounds in petroleum as an argument in favor of the hypothesis.

The objection has been urged against this hypothesis, that petroleum, if thus
produced, should be abundant in the primary rocks from which it is usually absent.
The originally heated condition of these rocks would have prevented the condensa-
tion of oil, however, and, although the vapors may have passed through the earlier
rocks, there is no reason to expect that condensation should have occurred before
reaching much higher strata.

While on geological grounds difficult to prove or disprove, it meets with one fatal
objection. The composition of natural gas in Pennsylvania does not justify the sup-
position that superheated steam and carbon have been concerned in its formation.
We should certainly look, in such a case, to find natural gas composed mainly of free
hydrogen containing small quantities of paraffins, olefines and carbon monoxide.
When it is considered that paraffins alone cannot under any known circumstances be
produced from the oxidation of carbide of iron by steam, the hypothesis does not
seem to be tenable.

It is true that varying conditions of temperature might have produced a great
variety of hydrocarbons, but no evidence has yet been obtained that paraffins alone
result from such a reaction. In an experiment made with ferromanganese and dilute
sulphuric acid, the gas evolved was found to contain 6 per cent. of olefines.* It is
further to be noticed that this hypothesis requires that water should take part in the
process, yielding up its hydrogen, while, according to the older geological hypothesis,
the water may have served mainly to cover and give protection from atmospheric
oxidation, if it has been concerned at all in the reaction.

Water contains dissolved oxygen, and in descending to the iron carbides, must
have given off its dissolved oxygen long before reaching the region at which actual
formation of hydrocarbons could occur. Hence, on this hypothesis, oxygen should
be found in natural gas in larger quantity than the chemical tests indicate. In fact
in rocks of moderately high conducting power, a wide interval would exist between
the depth at which water boils and the much greater depth at which water vapor
could oxidize metallic iron in quantity. It is doubtful whether water could have
traversed this interval so as to reach the latter depth at all.

Engler (Ber., Vol. XXI, p. 1816, and Vol. XXII, p. 592) has published the
results of interesting investigations upon the distillation products of menhaden fish
oil. By conducting the distillation at a high pressure (25 atmospheres), this
author produced a mixture of hydrocarbon oils from which a large number of normal

* Experiments by F. C. P.

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 227

paraffins was obtained, compounds not found elsewhere in nature than in pe-
troleum.

This has led to the revival of an older theory as to the origin of petroleum and
gas, ?. é., that they have resulted from the distillation under pressure and at low tem-
peratures of the accumulated remains of marine life buried under the sediments of
the ancient Devonian seas.

Much has been written in support of the hypothesis of Engler, and it may be
said to have gained very general acceptance in Europe.

Ochsenius (Chem. Zeitung, 1891, p. 936) has summarized many of the argu-
ments usually adduced in support of the hypothesis.

This author says, ‘Concerning the origin of petroleum, there is now no doubt
that, with a few exceptions, animal remains (mainly of marine life) have yielded the
raw material.”

Originally the opinion was held that it was derived from vegetable matters, be-
cause the accumulation of animal remains sufficient to account for its formation by
any distillation process in the rocks could not be explained. Distillation of vege-
table matters would, however, have left greater deposits of coal (as a residue in the
Devonian rocks). But petroleum occurs in rocks of marine formation where coal is ~
uncommon. Rocks in which plant remains are found do not contain bitumen (petro-
leum). If animal remains are associated with those of plants, then bitumen is usu-
ally found.

The objection urged against the hypothesis of Engler, that nitrogen does not
occur in petroleum, is easily overcome by the fact that nitrogen of animal tissues
tends finally to produce ammonia, and this in the case of petroleum may have been
carried away in solution by water; hence, the absence of nitrogen compounds.

From Engler’s experiments, it appears that animal fats are the chief source of
petroleum.

It is true that fatty matters do not ordinarily sink in water, although Von
Guembel, in the voyage of the Gazelle, found fat globules in dredgings from the
bottom of the Atlantic Ocean, in water 15,000 feet deep.

Putrefactive changes would tend to yield considerable quantities of ammonia
and carbon dioxide. These in presence of salt water would produce alkali bicarbon-
ate and ammonium chloride. Hence, alkaline waters might be looked for in the
neighborhood of petroleum. ‘The petroleum at Pechelbronn is associated with water
containing 0.5 per cent. of alkaline carbonate. (In Western Pennsylvania, many
cases are known of water having a decided alkaline reaction in the neighborhood of
gas wells. In the Murrysville gas territory, water of alkaline reaction was so abun-

228 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

dant as to seriously interfere with gas development. Note by F. C. P.) Such
alkaline waters are not known in archean rocks, and are not, therefore, likely to be
derived from greater depths than the rocks in which they are found.
Probably no cases can be cited where fatty tissues alone of buried animals haye -
yielded oil or gas. The presence of strongly saline water is apparently needed.
Great differences occur in the chemical character of petroleum. Caucasian oils
are mainly composed of olefines or substances related to the olefine group. The
German oils are mixtures of paraffins and olefines, while the American are chiefly
parafiins. Such differences may be attributed to the character of the rock in which
the distillation has occurred. Sandstones would probably prove without action ;
while limestones, by reason of their basic character, would tend to strongly influence
the products.
Such are some of the arguments of Ochsenius in favor of Engler’s hypothesis.
If this view is accepted, it follows that the generation of petroleum and gas
must be considered as a finished process, so far as all existing productive gas and
oil regions are concerned. ,
Engler has analyzed the gas evolved when (1) menhaden oil and (2) when oleic
acid are distilled under atmospheric pressure and under a pressure of 25 atmospheres.

MENHADEN OIL. OLEIC ACID.

1 armos. 25 ATMOs. 1 aTmMos. 25 ATMOS.
Methane s:i:iscciiva cars otic onle heccleloar eee een SR eee 25.2 38.3 9.3 4.36
Ol eA MES se Ss stale usin lerarsiaina’s eval sts Oaverlervetelereretatekereteletetiere tee 11.4 7.8 12.5 2.9
Carbon 'dioxider..)/ 2 \siisjeepleterscleie ciowrse ee iaiehe eterna eerie reversions 26.7 17.4 37.2 26.0
Carbon, MONO e%<\s:ciwseietareie strcioeieloeioeeeicioe eee ee eaneeee 34.9 34.5 38.6 25.5
Iincombustible sresiduer.cccrerviacrt-rleeieloets ceeteier ieereoet eee 1.8 2.0 2.4 2.0

(Ber., 1889, p. 592).

The liquid distillates produced at the same time that these gases were evolved
were rich in the normal paraffins and their isomers. |

100 parts of menhaden oil yielded 8.9 parts of gas and 63 parts of liquid oils.

A strong argument in support of the Engler hypothesis is found in the fact that
by distillation of fish oils, besides methane, several of the lower paraffins are pro-
duced in large quantity. Hydrocarbons of the paraffin series are not obtainable in
such proportions by the distillation at high temperatures of other organic material
under ordinary conditions.

It should be noted as a fact of much interest as regards the results of Hngler’s
researches, that in the distillation at higher pressures the proportion of olefines con-
tained in the gases evolved is considerably less. This is also true of carbon monox-
ide when oleic acid was distilled. It is to be regretted that Engler’s experiments

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 229

were not repeated at still higher pressures, in order to ascertain whether these same
constituents of the evolved gases diminish progressively with increased pressure.

Engler was the first to show clearly that the problem of the origin of oil and
gas must be studied from the chemical rather than the geological standpoint. The
hypothesis advanced by this author has been very generally accepted.

Nevertheless, my examinations of natural gas have led me to doubt some of his
conclusions, well founded as they seem. The most careful tests, carried on during a
period of six years, have failed to show the presence of either olefines or carbon
monoxide in the natural gas of Western Pennsylvania.

Some of the constituents of gas are soluble in water. This is notably the case
with carbon dioxide, butane, hexane, etc. If ethylene and carbon monoxide have
been produced even in much smaller proportion in the rocks than Hngler finds in
menhaden oil gas, these substances would now occur in the natural gas of Pennsyl-
vania. Hthylene would give to the gas such illuminating power that there would be
no occasion for the use of coal gas in any town in the Western Pennsylvania gas
region. Asa matter of fact, natural gas is almost useless as an illuminant, its light
being equal to 5 to 11 candles per five feet of gas consumed per hour.

Mr. Robert McKinney, formerly gas inspector of Allegheny county, found as a
mean of forty trials of natural gas supplied to Pittsburgh an illuminating power of
6.5 candles.

Mr. J. W. Patterson, the present gas inspector of the county, states that the
illuminating power of natural gas as supplied to Pittsburgh in November, 1892, is a
little less than 11 candles per five feet per hour. The reason for this is that natural
gas, as found in Pennsylvania, does not contain olefines. If carbon monoxide
occurred in gas, there would have been innumerable cases of poisoning among
workmen at gas wells. It is common to find such leaks of gas about the majority
of gas wells that no one could strike fire at a well without risk of fatal consequences.
Although inhaling the escaping gas for much of a lifetime, a gas-well driller will
usually maintain that no bad effects to health come from exposure to the gas. Air
containing 0.2 per cent. of CO is known to produce dangerous effects upon health.

According to Wyss (Zeit. Ang. Chem., 1888, p. 465), air containing 0.1 per
cent. of water gas is poisonous to breathe.

- It is hardly probable, moreover, that CO or C,H, occurring in gas could have
been absorbed or removed at low temperatures by any natural process in the rocks.
Unlike carbon dioxide and ammonia, their slight solubility in water would preclude
the supposition that they had been dissolved away. Muck (Grundziige und Ziele der

Steinkohlenchemie, 1881) cites analyses of fifty-seven samples of gas from coal mines
A. P. 8 VOL, XVI. 2D,

230 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

and of gas occluded in coal. In only one case is carbon monoxide mentioned, but it
is distinctly stated that its occurrence was not proyed. Ethylene is mentioned in
six cases, but Muck states that more recent analyses have failed to demonstrate its
presence usually in gas from coal. The absence of hydrogen in all the analyses is
especially noticeable. In the case of gases from the Caspian region, the presence of
ethylene and carbon monoxide is to be anticipated, as, from all accounts, subterra-
nean heat has been concerned in their production (see Table of Analyses).

Thomas ( Watt’s Dic., Third Supp., p. 529) gives analyses of fourteen samples
of gas occluded by coal and also of gas from blowers in coal mines in New South
Wales. The analyses showed the presence of methane, nitrogen, carbon dioxide
and oxygen; but no carbon monoxide, hydrogen or ethylene was found. Franke
(J. Pr. Chem. (2), XX XVII, pp. 101, 113) gives analyses of mine gases, according
to which only carbon dioxide and methane were found. Winkler (Jahresb., 1882,
p. 1063) found no hydrogen in nine samples of mine gas. Many similar statements
might be cited, all tending to prove that hydrogen, ethylene and carbon monoxide
do not occur in gases occluded in coal.

The occurrence of gas consisting of nearly pure nitrogen, such as that obtained
at Middlesborough, England (see Table of Analyses), in a region therefore where
gas similar to Pennsylvania natural gas might be looked for, may perhaps be ex-
plained by the action of subterranean water upon deposits of coal or bituminous
shale. ‘The dissolved air in such waters, by causing slow oxidation, might lead to

CONSTITUENTS. | 1 | P) as 4 5 | 6 | 7 8
Carbonsmonoxid en. reine ener | 0 | 0 0 | 0 | 0 | 0 | 0 0
Carbon dioxide gevecenceacnnereeee | » 0.95 | 2.18 3.50 | 0. ls paar 4.44 | 0 0.3
Olefines........ Mn ashe ae | adit) aoe |. salen esa fo| Mao 0
Methane: rata.(ais)cdtoieaae tigen inne ees | 92.49 | 93.07| 92.24 95.39 | 97.57] 95.56] 1.90 | a
Hydroventscoc.crue aan sence nee | 0.94 | 0.98 Oc a4 y AU gee Bete eh ie laren ae
WN itropeniet wisest Si mate | 213} 0.49 ae ee nee vase] OGG |) Sie
OXY EDI orate raisreijelere atrereisssrejasieleey Dee | Aor | Siete diel’ Sistus siatate weet 1.53 | 2.9

——— IE ose Bs ; : e -—| —~—.|--—_
100.62 | 99.98) 100.00 .... | 100.04 100.00 | 100.00 | 100.00
| |

Nos. 1, 2, 3, 4, 5 and 6, natural gas from the Caspian region. Communicated by letter from Mr. M. Belianing,
of Nobel Bros., St. Petersburg. No. 4 is the result of a partial analysis. Nos. 7 and 8, gas obtained by deep
borings at Middlesborough, England (Bedson, J. Ch. Soc., 1888, p. 662).

the production of carbon dioxide and the consequent removal of oxygen from the

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 231

water. The carbon dioxide produced would lessen the solubility of the water for
nitrogen by causing the water to dissolve carbonate of lime, ete. Gentle heat from
below would tend still further to the expulsion of the nitrogen, and thus a consider-
able but limited quantity of nitrogen might be obtained as a sudden outburst from
a drill hole.

It may be said that varying conditions of temperature and pressure, and kind of
rock, have modified the products, so that perhaps the carbon monoxide and ethylene
resulting from a laboratory experiment have, in nature’s workshop, given place to
- paraffins.

But, if the chemistry of the reaction supposed to occur is to be considered at
all, the fact that distillation experiments have produced from fish oil certain bodies
found in natural gas (paraffins), should not count more forcibly as geological evi-
dence than the other fact, that such distillation yields bodies which are foreign to
natural gas as usually found in Pennsylvania.

I have failed to find any data tending to show that organic matter can be sub-
jected to destructive distiliation in such a manner as not to yield carbon monoxide
and considerable quantities of olefines, together with hydrocarbons of still less sat-
urated character. As a rule, the acetylenes and benzol series appear. Engler’s
hypothesis involves the supposition that a process of distillation has occurred at
moderately high temperatures and at pressures measured by great depth of rock
strata. The carbon dioxide evolved in this destructive distillation must have come
continuously into contact with the vast quantities of carbon, which in its various
stages of transformation from vegetable tissue to anthracite is so widely distributed
throughout the rocks. The reaction CO, + C = 2 CO, which proceeds rapidly at a
strong heat and also slowly at lower temperatures, would then probably have oc-
curred, wherever the temperature was sufficiently high.

Prolonged contact of carbon dioxide with the carbonaceous residue of the dis-
tillation would perhaps be sufficient to increase considerably the final yield of carbon
monoxide.

According to I. L. Bell (Chemical Principles of the Manufacture of Iron and
Steel, p. 101) the reduction of carbon dioxide to carbon monoxide by carbon in the
form of soft coke begins at 427° C.

This is about the temperature at which Engler’s distillation experiments were
conducted (360°-420° C.).

Engler has shown that distillation of animal fats at very high pressure (25 at-
mospheres) may yield gas containing less of carbon monoxide and olefines than
when the process is conducted under atmospheric pressure. No data are at hand as

232 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

to results at still higher pressure. If it is conceded that the proportion of carbon
monoxide and ethylene in the gas evolved during destructive distillation decreases
progressively with increase of pressure, and that these two constituents vanish alto-
gether at sufficiently high pressures, it would still seem necessary to suppose that
the pressure must have been at least twice as great when the process occurred in the
rocks, as in the case of Engler’s experiments.

Taking the specific gravity of the rocks to be about 25, it may be assumed that
twelve feet of rock strata represent a pressure of 1 atmosphere, six hundred feet of
solid rock would then be required to produce a pressure of 50 atmospheres. This
would be considerably less than the depth of the same quantity of rock material in
the form of loose sediment, before its consolidation. No case can be cited in recent
times where sediment six hundred feet deep has been so suddenly accumulated as to
bury unchanged the vast quantities of animal remains necessary to account for the
production of oil and gas upon Engler’s hypothesis, that oil and gas have resulted
from the action of pressure and moderate heat upon animal matters.

There is probably no reason to suppose that the gaseous olefines have, under the
influence of pressure, given place to others of higher boiling point, by a process of
polymerization. Should the possibility of such a change be proved, the absence of
olefines from natural gas and their presence in petroleum might be explained. The
possibility of secondary reactions among the constituents of a complex gas mixture
at high temperatures and under pressure, adds difficulty to the problem, and caution
is needed to avoid the error of overestimating the importance of any given reaction.

It is generally true, however, that under such conditions secondary changes are
probable, and that unsaturated compounds—olefines, acetylenes, carbon monoxide—
are likely to result, especially when water vapor and carbon dioxide are present.

It is a well-known fact, that when petroleum is distilled, considerable quantities
of unsaturated hydrocarbons are produced which did not exist in the original crude
oil. This is shown by the bromine absorption of the different products. The pro-
cess of “cracking” or breaking up by heat of the hydrocarbons in petroleum into
simpler and less saturated compounds, is familiar to all oil refiners. Chemically
speaking, “cracking ” means the production of unsaturated hydrocarbons.

The fact that Engler has, in his extremely interesting and important researches,
produced by distillation of animal matters, so great a variety of paraffins, constitutes
by far the strongest argument in favor of his hypothesis.

Sorge, in an article which has been reproduced in numerous journals (J. Ch.
Soc., 1888, p. 31, abstract), has stated, that a strong resemblance exists between
Pennsylvania natural gas and gas manufactured from Westphalian coal. Similarity

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 233

in composition between natural gas and coal gas would greatly simplify the problem
of origin, and the fact of such similarity would prove of great interest. In this con-
nection, the following analysis of gas from Westphalian coal, carried out in the lab-
oratory of the Westphalian Berggewerkschaftskasse in Bochum, will be of interest.
I am indebted to Mr. Bergassessor H. Krabler, of Bochum, for the figures which he
has kindly communicated by letter.

it, 2.
lebyehocnnooms, Calbls ocacoadonedosnoanc oo p0nb00d 00g oUGuGO0 D000 DUo0 Dou DonuGHODODOOD DOO OOOD 5 4
Ie (han eh actacs joo n as hoccares PR Nee Oe ett otaeremiaiale ateee ala eicate nie ate data seis Gina lelanasdie wa te Ay eso
ISUVOROBER » ooo oc0g do sop eo obo dDOoONA TODOS OONADOOU DoagUDAOOSA oC GOUsODSOCDDMOOOODOREDDOSOGOC 40 50
CO scccorwoa dove ccoocndagsaduoodocouabodose 6 loedodobnodne dodeadnn dhe roonoo coon oUOrenOnOsC 5
OO), sccoccastddcusoomeddoodnodondvebuheddonnsacusoudasbe gag cdeaddo. dao Snond tI sednae Deb Odd 1 3
INMTPOGEM p oanoavandbodegoodsconutunnad oo nopHOdooDoCGu ad UNO MOU Boson DDoODDd OUD OSONOOUURDOO + 3

The large percentage of hydrogen and the proportion of CO in this gas illustrate at
once the results of high temperature in the production of the coal gas, but a similarity
between this coal gas and natural gas can hardly be said to exist.

When vegetable remains are buried under water, as is well known, decomposi-
tion occurs, yielding gas in considerable quantity.

Tappeiner (Ber., 1883, p. 1734) has studied the products of this change very
exhaustively.

Pure cellulose (filter paper) was found, under the influence of a microbe which
was supplied with nutritive fluids, to dissolve in water, yielding gas mixtures of two
different types.

UNDER WATER OF NEUTRAL UNDER SLIGHTLY ALKA-
REACTION. LINE WATER.
AT BEGINNING. AT END.

(Chidoem CHONG. codccr euaoocadadod9GQNNeS Beds uericenit: #08 par cent: Ba9/ per cont
Elividro genus tll p hid @yajl-y-1iteieiel«loleleletalelsie)sievere
EWG GEM a5 oaccana00005 b00bonedc0DGR005000 0.0 ne 0.0 ss 42.71 ut
MICO AG. 5 oonas0590HoAsdoscOSbORoSONRbOGGGS 11.86 se ZENO 0.0 as
INNO NS Jo's odapocobosee acon ot eeecoboas 2.73 oe 0.0 sf 1.90 ae

From these experiments it appears that, by the action of a microbe, either
methane and carbon dioxide (neutral fluid), or hydrogen and carbon dioxide (alka-
line fluid) may result. Hoppeseyler (Ber., 1883, p. 122) found that gas evolved in
the decay of cellulose under the influence of a microbe (marsh-gas fermentation)
contained :

234. RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

Popoff finds in a gas from decaying vegetable matters :

Marsh. 2 a8'6.aisse.die ie ovouese) waved Wartecovetere aye sos fecal nsselale orelerale vetoes cetera ie teretal oleretsreleGeeseicietererateecaetere 68 56 per cent.

Carbon dioxide... ic ejects p:daieebais ners bila eiere ercierl Mors etioiererey aletere lovee tle reo ne eRe Ere 31.44 *

Berthelot states that hydrogen is produced in the vinous fermentation of man-
nite. In very careful experiments which I have tried I have failed to find hydrogen
in the gas evolved during the fermentation of 200 gms. of sugar. Chemical changes
of this type are not likely to be of importance, however, as regards the hydrogen
question.

GASES FROM SEA WEEDS.

The following experiments were tried in order to study the nature of the gases
evolved in the decay of sea weeds:

A quantity of a large fucus kind from Santa Barbara, Cal., was used. 50 gms.
of the air-dried plant were soaked in water and then introduced into a flask filled
with water, which had been previously boiled (in order to expel air) and cooled. The
flask was connected with a belljar over a mercury trough. After setting up the
apparatus, no gas appeared until the third day; then a strong evolution of gas
began and continued in slowly diminishing quantity for ten days, when the process
ceased. In all, 803 c.c. of gas were collected. Analyses weré made (1) of the first
portion of 300 ¢.c., (2) of a second portion of 300 ec., and (3) of the last portion
of 203 c.c. The results are tabulated below.

FIRST PORTION. SECOND PORTION. THIRD PORTION.
Carbon dioxides eer secre eerie eee ee eerne 18.23 per cent. 32.47 per cent. 53.44 per cent.
Carbonsmonoxides ene ete eee eeereerern 0 és 0 fs 0 “s
Mihylene<cirncctss etoeeiet eee eer eee 0 at 0 ee 0 se
Methane.) .(5it.niscce acinar eee eer eee ee ei 0:0 aa O28 O08 acs
Ly Gro genet tice -tsersaiemeg Sak een mice 62.24 “ ASIST | Ve 42:02 9°
INUbPO BON rec lecaib:d, eastern ATER 19.23 9 S328 secs ATEGe es

100.00 100.00 100.00

Carbon dioxide was determined by soda solution over mercury; hydrogen by
palladium asbestos, using a Hempel apparatus. The absence of CO and C,H, was
proved by palladium chloride solution. Methane was determined by combustion
with air, using a red-hot platinum tube. The carbon dioxide produced in the com-
bustion was absorbed by baryta solution of known strength, and the excess of
baryta determined by standard oxalic acid. The following facts are of especial
interest :

1. The carbon dioxide increases towards the end of the decay. 2. The hydro-
gen steadily diminishes. 3. Methane occurs only in traces. 4. Nitrogen occurs in

RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 235

such considerable quantity as to render it probable that this gas is set free in the
process of decay.

The same apparatus was kept in position for two and a half years after the
above experiments were finished. During that time a continuous production of gas
was observed, but it was so slow that at the end of this period only about 30 c.c. of
gas collected. This was found to consist of methane.

I have examined the gases produced in swampy ground in many different places.
Samples were taken from streams having muddy bottoms and in which vegetable
matter had collected. Samples of gas have also been taken from salt marshes on
the coast of Maine. Gas has also been collected from the very deep accumulations
of mud and decaying vegetable remains found in some parts of Lake Chautauqua.
The general result of examinations of these gas samples may be stated to the effect
that the gas occurring in shallow swamps and streams consists of methane, carbon
dioxide and nitrogen. In some of the much deeper swamp waters, where masses of
vegetable débris of greater thickness are found (as in Lake Chautauqua), hydrogen
occurs in very small quantity. Great difficulty is experienced in taking samples of
gas from localities of the latter type. ‘T'appeiner observes that the marsh-gas fer-
mentation is very probably a very important source of methane in nature.

The fact that buried vegetable matters may, after a brief period of rapid gas
evolution, pass into a condition of extremely slow decay, adds greater force to the
original theory of petroleum and gas. The occurrence of so large a proportion of
free hydrogen among the gases evolved by vegetation in process of decay is a matter
of great interest, as it suggests the existence of an important source of hydrogen

wherever deeply submerged plant remains occur. Frankland (J. Ch. Soc., 1883,
p. 295) found that grass left to decay under water (air being excluded) evolved gas
in three days of the following composition:

CW AUDOURAIOXIG emetic terete erevore elena cteferentetevorein| ic ercicis * ors'e!savetelsisyeieielsfere) sieieieivve e'eis 84.63 per cent.
ORVEON sccaccc0se » odpn00d00 2690 c0accabea7QG00000c0dC odccbon5 70000 DUONUCOuUaDObdDN 0.18 s
Ply UROL Wetarataretetalelelstelitol tele! otntels!al=/ols’ele\plolel+/slelslelsla/a\cle)vive(siis| «le\sic\r\»ie/a\cie.0\alelcle/e\e\elelsie/eiela /s1e1e\~ 6.90 sf
Opie raCOMMMUS LOM CASES steatstelstelelatci-vetetelelefaletel-tsloteleyea!clelelstetelstel siete cieleis) s/els cieisialwicis/cleislelerelele’s 2.51 «
ISRO ocon¢oag0 Geno caso gg sondsoeanonOnObSbONDoON ado DEdoscuoNbSoapE SHagborooonNc 5.83 4

Vegetable tissue, after the somewhat sudden and tumultuous evolution of gas,
seems to be capable of relapsing into an extremely slow and long continued process
of decay. After the first decomposition, such remains might become accumulated
and buried deeply under sediments before the tissues are materially altered. The
generation of gas might then proceed in the cold. It seems hardly possible to ignore
this probable source of natural gas in discussing any theory as to its origin, espe-

236 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES.

cially when it is considered that no other process in nature has been found to yield
a gas at all similar in composition to that found in the rocks.

Of the three hypotheses which have been proposed to account for the production
of oil and gas, two are open to a serious objection.

The chemical changes supposed by Engler to have been the cause, would prob-
ably yield gas different in composition from the natural gas now being obtained in
such large quantity in Western Pennsylvania, and if the gas originally contained
ethylene and carbon monoxide it is not easy to explain their complete disappearance
in the natural gas I have examined from wells scattered over so large a region.

The hypothesis of Mendeléeff would be much more difficult to reconcile with
the facts as regards composition. The total absence of hydrogen could not be easily
explained. The only process in nature which is known to yield gas similar in its
constituents to natural gas is that which occurs in swamps and decaying masses of
submerged vegetable remains.

The important fact that the solid plant tissues may be preserved for long
periods after the preliminary gas evolution has ceased shows that the remains are
likely to become slowly buried, to undergo the “fermentation” changes leading to
the production of methane.

Animal tissues can suffer no such arrest of decomposition. Decay once set in
is carried rapidly onward to complete destruction without intermission. The con-
trast between the conditions in which animal and plant remains occur in the rocks
seems to justify this statement.

If chemical evidence shall count in the discussion, it is difficult to find a more
satisfactory explanation than the older hypotheses which the geologists advanced,
although in their treatment of the subject the strictly chemical arguments were
neglected.

TRANSACTIONS

OF THE

AMERICAN PHILOSOPHICAL SOCIETY,

HELD AT PHILADELPHIA,

FOR PROMOTING USEFUL KNOWLEDGE.

> VOL. XVIL—NEW SERIES.
PART I.

RTICLE I.—Description of a Skull of Megalonyx leidyi, n. sp. (with five plates). By

Josua Lindahl, Ph.D., te ee : L j : : f ber Sahat
Amicus II.—On the Homologies of the Posterior Cranial Arches in the Reptilia ad Jive
plates). By B.D. Cope, . : : . , ; : : ; ALE
RTICLE IIL—A Synopsis of the Species of the Teid Genus Onemidophorus (with eight
n plates). By H, D. Cope, ...-: : j : ; mere : .- 27
pene Coca, [A 45198

es 17 19>
PHilatelphia:
PUBLISHED BY: PHAR SOCIETY,
AND FOR SALE BY
THe AMERICAN PuitosopHicat Society, PHILADELPHIA :
N. TRUBNER & 00,57 & 59 LUDGATE HILL, LONDON.

PRINTED BY MAC CALLA & COMPANY.

1892:

EXTRACT FROM THE LAWS.

CHAPTER XII.

OF THE MAGELLANIC FUND.

Section 1.’ John Hyacinth de Magellan, in London, having in the year 1786 ‘
offered to the Society, as a donation, the sum of two hundred guineas, to be by the
vested in a secure and permanent fund, to the end that the interest arising therefrom
should be annually disposed of in premiums, to be adjudged by them to the author ot
the best discovery, or most useful invention, relating to Navigation, Astronomy, or Nat- 2
ural Philosophy (mere natural history only excepted); and the Society having accepted ©
of the above donation, they hereby publish the conditions, prescribed by the donor ane d

agreed to by the Society, upon which the said annual premiums will be awarded.
~
CONDITIONS OF THE MAGELLANIC PREMIUM.

1. The candidate shall send his discovery, invention or improvement, addressed
to the President, or one of the Vice-Presidents of the Society, free of postage or other
charges; and shall distinguish his performance by some motto, device, or other sig
ture, at his pleasure. ‘Together with his discovery, invention or improvement, he shall
also send a sealed letter containing the same motto, device or pare and subscribe d
with the real name and place of residence of the author. o

2. Persons of any nation, sect or denomination whatever, shall ee admitted as | c an. :
didates for this premium. re

3. No discovery, invention or improvement shall be entitled to this prem nium,
which hath been already published, or for which the author hath i pabiicly rewarded
ade | =
. The candidate shall communicate his discovery, invention or improvement it
Bek in the English, French, German or Latin language. ae

5. All such communications shall be publicly read or exhibited to the sacle
some stated meeting, not less than one month previous to the day of adjudication, am
shall at all times be open to the inspection of such members as shall desire it. But 1 7
member shall carry home with him the communication, description, or model except the
officer to whom it shall be entrusted; nor shall such officer part with the same out ¢ of
his custody, without a special order of the Society for that purpose, ~ ae

6. The Society, having previously referred the several communications from can-
didates for the premium, then depending, to the consideration of the twelve counsclael de ue
ors and other officers of the Society, and having received their report thereon, shall,
at one of their stated meetings in the month of December, annually, after the expira-
tion of this current year (of the time and place, together with the particular occasion
of which meeting due notice shall be previously given, by public advertisement) pro-
ceed to final adjudication of the said premium; and, after due consideration had, a vote
shall first be taken on this ‘question, viz.: Whether any of the communications then
under inspection be worthy of the proposed premium? Tf this question be determined
in the negative, the whole business shall be deferred till another year; but if in the
afirmative, the Society shall proceed to determine by ballot, given by the members at

ator
oo a be

large, the discovery, invention or improvement most useful and worthy; and that.
discovery, invention or improvement which shall be found to have a majority of con-
curring votes in its favor shall be successful; and then, and not till then, the sealed
letter accompanying the crowned performance shall be opened, and the name of the
author announced as the person entitled to the said premium.

* 7. No member of the Society who is a candidate for the premium then dependifig, —
or who hath not previously declared to the Society, that he has considered and weighed
according to the best of his judgment, the comparative merits of the several claims
then under consideration, shall sit in judgment, or give his vote in awardihg the said
premium.

8. A full account of the crowned subject shall be published by the Society, as soon
as may be after the adjudication, either in a separate publication, or in the next suc-
ceeding volume of their Transactions, or in both.

9. The unsuccessful performances shall remain under consideration, and their
authors be considered as cafdidates for the premium for five years next succeeding the
time of their presentment; except such performances as their authors may, in the
meantime, think fit to withdraw. And the Society shall annually publish an abstract of

the titles, object, or subject matter of the communications, so under consideration ;

such only excepted as the Society shall think not worthy of public notice.
10. The letters containing the names of authors whose performances shall be

rejected, or which shall be found unsuccessful after a trial of five years, shall be burnt

before the Society, without breaking the seals.

i1. In case there should be a failure, in any year, of any communication worthy of
the proposed premium, there will then be two premiums to be awarded the next year.
But no accumulation of premiums shall entitle the author to more than one premitim
for any one discovery, invention or improvement.

12. [he premium shall consist of an oval plate of solid standard gold of the ie
of ten guineas. On one side thereof shall be neatly engraved a short Latin motto
suited to the occasion, together with the words: “The Premium of John Hyacinth de
Mageilan, of London, established in the year 1786; and on the other side of the

‘ plate shall be engraved these words: “Awarded by the A. P. S. for the discovery of

A.D, .’ And the seal of the Society shall be annexed to the medal by a
ribbon passing through a small-hole at the lower edge thereof.

SECTION 2.- The Magellanic fund of two hundred guineas. shall be considered as
ten hundred and fifty dollars, and shall be invested a eeately from the other funds be-
longing to or under the care of the Society, and a separate and distinct account of it
shall be kept by the treasurer.

The said fund shall be credited with the sum of one hundred dollars, to represent
the two premiums for which the Society is now liable.

The treasurer shall credit the said fund with the interest received on the invest-
ment thereof, and, if any surplus of said interest shall remain after providing for the
premiums which may then be demandable, said surplus shall be used by the Society for
making publication of the terms of the said premium, and for such purposes as may be
authorized by its charter and laws.

The‘ treasurer shall, at the first stated meeting of the Society in the month of
December. annually, make a report of the state of said fund and of the investment
thereof. :

I—XVI.

Price, eighty dollars.
Address,

Sy’

v..

TRANSACTIONS

OF THE

HELD AT PHILADELPHIA,
FOR PROMOTING USEFUL KNOWLEDGE.

VOL. XVIT.—-NEW SERIES.

PART Il. ZPI3A 9S
| pede See eat (FUN 27.1892 -
So
ARTICLE IV.

‘The Tribute Roll of Montezuma (with six plates). Edited by Dr. Daniel G.
* Brinton, Henry Phillips, Jr.,; and Dr. J. Cheston Morris.

Opaae 1.—The Written Language of the Ancient Mexicans. By Daniel G. Brinton, M.D., LL.D.
Parr UL—The Tribute Roll. By Henry Phillips, Jr.

PART TIl.— Physical and Ethnographical Characteristics. By Dr. J. Cheston Morris.

é
—_—_

Philadelphia:

FUBTISHED BY THE SOCIETY,
AND FOR SALE BY
Tue American Puirosopuicar Society, PuHirapeLputa :
N. TRUBNER & CO. 57 & 59 LUDGATE HILL, LONDON.

PRINTED BY MAC CALLA & COMPANY.

1892.

EXTRACT FROM THE LAWS.

THE HENRY M. PHILLIPS PRIZE ESSAY ape

—

Miss Emily Phillips, of Philadelphia, a sister of Hon. Henry M. Phillips, ie od,
presented to the American Philosophical Society, held at Philadelphia for Promotiag a

Useful Knowledge, on October 5, 1888, the sum of five thousand dollars for the esta
lishment and endowment of a Prize Fund, in memory of her deceased brother, 1 si
was an honored member of the Society, The Society, at a stated meeting, held Oc cto. o-

ber 5, 1888, accepted the gift and agreed to make suitable rules and regulations to to

carry out the wishes of the donor, and to pret the duties confided to it nh

a stated meeting held on the seventh day of accu s A.D 1888234 x .

First. The Prize Endowment Fund shall be called the “ Henry M. Phin B
Essay Fund.” be

Second. The money constituting the Endowment Fund, viz., five te dollar ar
shall be invested by the Society in such securities as may be recognized by the “a
Pennsylvania, as proper for the investment of trust funds, and the evidences of such
investment shall be made in the name of the Society as Trustee of the Henry } M. .

Phillips’ Prize Essay Fund. fe we ee.

Third. The income arising from such investment shall be appropriated as wee

(z) To making public advertisement of the prize and the sum or amount in |
United States gold coin, and the terms on which it shall be awarded. _ ;

(+) To the payment of such prize or prizes as may from time to time be swathed “2 is
by the Society for the best essay of real merit on the Science and Philosophy of Juris 5 ate
prudence, and to the preparation of the certificate to be granted to the author of any so

successful essay.

Fourth. Competitors for the prize shall affix to their essays some motto or name
(not the proper name of the author, however), and when the essay is forwarded to the
Society, it shall be accompanied by a sealed envelope containing within the proper
name of the author, and, on the outside thereof, the motto or name adopted for the
essay.

fifth. Ata stated meeting of the Society, in pursuance of the advertisement, all

essays received up to that time shall be referred to a Committee.of Judges, to consist

Stath. All amounts of interest accruing and unexpended on each and every occa-
~ sion on which no prize shall be awarded, shall be considered and taken as accretions to
e principal of the said fund. |

ay . “Seventh, All essays may be written in English, French, German, Dutch, Italian,
‘ panish or Latin; but, if any language except English, must be accompanied by an

Paes » English translation of the same.

prize, or profit, or honor, of any nature whatsoever.

Ninth. All essays must be clearly and legibly written on only one side of the

; Tenth, The literary property of such essays shall be in their authors, subject to
the tight of the Society to publish the crowned essays in its Transactions or Pro-
ceedings. |

Eleventh, A Standing Committee, to consist of five members appointed by the
” President, and ex officio, the President and the Treasurer of the Society, shall continue
in office during the pleasure of the Society, and any vacancies that miay occur in said
_ Committee shall be filled by new appointment by the President.

| Twelfth, The said Committee shall have charge of all matters connected with the
management of this endowment and the investment of the same, and shall make such

be ak general rules for publishing the terms upon which said prize shall be competed for, and

the amount of the said prize, and, if it shall deem it expedient, designate the sub
for competing essays. It shall report annually to the Society, on the first Friday
December, all its transactions, with an account of the investment of the Prize Fi
andl of the income and expenditures thereof. | :

The first prize to be awarded by the Society will be the sum of one thousand « |
lawful gold coin of the United States of America, and all treatises competition t ‘
Sor must be in the possession of the Society before the first day of Fanuary, 1893.

The prize will be awarded for ‘* The best Treatise on the History and Gro
the Phitosophy of Furisprudence, dinded into Ancient, Medieval and Modern |
presenting a complete conspectus of the literature, bibliography and Rees pertai
the icin

NOTICE.

Preceding Volumes of the New Series can Ee obtained from the Libraria
Hall of the Society. — Price, five dollars each, A Volume consists Be three Parts
separate Parts will not be disposed of. .

A few complete sets can be obtained of the Tisdehede New Series, |
I—XVI. Price, eighty dollars.

Address, ‘THE LIBRARIAN. _

TRANSACTIONS

_ AMERICAN PHILOSOPHICAL SOCIETY

FOR PROMOTING USEFUL KNOWLEDGE.

VOLUME XVII—NEW SERIES.

PART III

CLE V.—The Saprolegniacer of the United States, with Notes on Other Species (with seven plates),
% By James Ellis Humphrey, Sc.D.
RTICLE VI.—Researches upon the Phenomena of Oxidation and Uhemical Properties of Gases (with
three cuts and two plates). By Francis C. Phillips, Ph.D.

#hilavelphia: We ee boN
PUBLISHED BY THE SOCIETY, Nee

AND FOR SALE BY

THe AMERICAN Puitosopnican Society, PHirapeLPHIa

N. TRUBNER & OCO., 57 and 59 LUDGATE HILL, LONDON.

PRINTED BY MACCALLA & COMPANY.

1893.

EXTRACT FROM THE LAWS.

THE HENRY M. PHILLIPS PRIZE ESSAY FUND.

Miss Emily Phillips, of Philadelphia, a sister of Hon. Henry M. Phillips, deceas ed
presented to the American Philosophical Society, held at Philadelphia for Prom oti :
Useful Knowledge, the sum of five thousand dollars for the establishment and er do we
ment of a Prize Fund, in memory of her deceased brother, who was an honor -
member of the Society. The Society accepted the gift and agreed to make suita
rules and regulations to carry out the wishes of the donor, and to discharge # .
duties confided to it. In furtherance whereof, the following rules and regniang

7 eo .
re

were adopted by the Society :

First. The Prize Endowment Fund shale peceailed cae Henry M. ae rize
Essay Fund.” %.

Second. The money constituting the Endowment Fund, viz., five chicane
shall be invested by the Society in such securities as may be recognized by see
Pennsylvania, as proper for the investment of trust funds, and the evidences of s
investment shall be made in the name of the Society as Trustee of the ica
Phillips Prize Essay Fund. “3

Third. The income arising from such investment shall be appropriated as follows : ii:

(a) To making public advertisement of the prize and the sum or amount in United a
States gold coin, and the terms on which it shall be awarded. | ve:

(4) To the payment of such prize or prizes as may from time to time be awarded . .

by the Society for the best essay of real merit on the Science and Philosophy of Juris- }

Ben

inted, or for which rhe author has received aia, any

be in the possession of the Society before the first day of Fanuary, 1895. The 3 Y -

upon which essays are to be furnished by competitors are as follows -

I. Ihe sources, formation and development of what 1s generally deSienated the —
Common Law of England.

2. The theory of the State, treated historically and upon principle, with a discus-
sion of the various schools of classical, medieval, and modern thought upon the subject.

3. ' The historical and doctrinal relations of the Roman Law and the English
Law, illustrated by parallels and contrasts.

five hundred dollars lawful gold coin of the United States, to be pard upon the aware
of the Prize.

The essays must be sent, addressed to Frederick Fraley, President of the

NOTICE.

Preceding Volumes of the New Series can be obtained from the Librarian at t 1e
Hall of the Society. Price, five dollars each. A Volume consists of three Parts ; but — "

separate Parts will not be disposed of.

A few complete sets can be obtained of the Transactions, New ‘Series, Vols. 4
I—XVII. Price, eighty-five dollars. ,

Bess ah THE LIBRARL

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