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UNITED STATES GEOLOGICAL SURVEY -
CHARLES D. WALCOTT, DIRECTOR
PSEUDOCERATITES OF THE CRETACEOUS
BY
ZA oP ee BU See
Edited by T. W. STANTON
SAID sh
ese 33
WASHINGTON
GOVERNMENT PRINTING OFFICE
1903
CONTENTS.
PIE REPRE A eae eae = io aia.-5 32 = sneak? == x onicinie de one ee aero n in aa casea Sai
Classified list’ of families, genera, and species. ......---2---------2 2255s occ corner
MahlevomhoriZzousescaac-- =~ 2s -= 6 ---- 22 2 0 no oe ees WBROREEpecen oa nace seas
GanGraleremarkameeet sys site tae aig sl om ccis masse ce rie lame asin so alae cl en ile a
Systematic descriptions =-..-.-.---------<4--40 0-20 sen en Saree paces nso sansa ae
ATES, 255 seca CR ABC OO EHR ese He on ne cre a 0oS os see Une sche OSS
TUOYIET= oN TLCS | yn PMH eee SS SCG Ts oes or cig sce i a
TERE ee Eee ERS RE BRE Mere doo. se och: So SCOURS Sole oa
PaenOLscO teeny eer ese = o-oo einlel= in me elo ee acres a cease eee ened
TCA ECD: pale au ee eRe cu SC operate coseaaoe Deion nes lbe Snot ae SoS ace
Rahenouiecidiene 22-2). o24- sc - neni ore sae nee acer aon ok eee
Rinlophoceratidee <<. 2. 2=20.---2-=-c0- «sto == sae maa ceaen ges 5 4) ge Mie ama
Goilapoceratidse - 2a. ca= -_a Janeen ocuePoc ca nUB SIGS ogres
Palchellidses. esc ccec 2 ers eee oe ele eee ei ie es a
IRE TTTCG TANG EOE esos oe oe aie Scalia tole a eae aaa ie a
Rin porOCera tds 3.xict2~ Seo. <—==—-S geeein = mene a ae on ae aes ar er aca
Plncenticerati tet: ese 2. cacao sce Seer ee =e meee eee eae ae ma ao na oe ee
Ra eerie <2 S20 aes eae epson rosa oe, eit Re Ln eee
lates secee = eee eee =e Bs SH oy ORS obo. ea aOR SRO ROU r yp sORo FOOT In
iimgles< oe cease. Soemecieendas Dee en eb RS DEE ABCC Ona oRe ho SosSe Cncehc GQStnE GES Ce
5
“a.
eae
PLATE 1.
Il.
Ill.
IV.
V.
VI.
‘AUIS
VIII.
XII.
ITI.
Figs. 1-3.
4-9.
10-14.
15.
Figs. 1-3.
3. Roemeroceras subplanum Hyatt [.-.-------.---------------------+---- 256
. Paratissotia regularis Hyatt \
. Sphenodiscus pleurisepta (Conrad) J
3. Sphenodiscus pleurisepta (Conrad),
. Sphenodiscus stantoni Hyatt _ {NCE a tae © er eae MD
. Sphenodiscus lobatus (Tuomey )
. Sphenodiscus beecheri Hyatt |
. Sphenodiscus stantoni Hyatt | ae ye pe OP Ms aL
. Sphenodiscus lenticularis (Owen) \
. Sphenodiscus lenticuiaris var. splendens Hyatt J
. Sphenodiscus lenticularis (Owen)
9. Sphenodiscus lenticularis var. mississippiensis Hyatt
. Sphenodiscus beecheri Hyatt | fae ae tae
. Coilopoceras novimexicanum Hyatt)
. Coilopoceras colleti Hyatt
. Eulophoceras natalense Hyatt —p---------------2- 20-222 t eect errr 27
3. Aconeceras nisum (d’Orbigny)
2. Metoicoceras swallovi (Shumard I
ILLUSTRATIONS.
Mojsisovicsia durfeldi Steinmann
Buchiceras bilobatum Hyatt |
Roemeroceras syriaciforme Hyatt oasekrsyer we Goer, ee ee Meena
Roemeroceras attenuatum (Hyatt)
Roemeroceras gabbi Hyatt
. Paratissotia serrata (Hyatt)
. Sphenodiscus pleurisepta (Conrad) .-.---.--------------+-+++-++++--+---- 260
264
. Sphenodiscus pleurisepta (Conrad
. Sphenodiscus lobatus (Tuomey ) .-------------------------- ede semiceeee 266
270
3. Sphenodiscus lobatus (Tuomey )
. Coilopoceras colleti Hyatt
. Metoicoceras swalloyi (Shumard )
3. Coilopoceras springeri Hyatt
276
. Coilopoceras grossouyrei Hyatt
. Sphenodiscus konincki Hyatt
. Metoicoceras whitei Hyatt
8
PLATE XUV.
XVI.
XMVIL.
MVINT.
XIX.
2. O. G5
XXIII.
XXIV.
XXVIT.
XXVIII.
Figs. 1-10.
11-14.
15.
16.
= Higs. 1-4:
5-8.
9-11.
12-18.
19-20.
Figs. 1-38.
48.
9, 10.
11-14.
15-18.
. Knemiceras compressum var. subecompressum
5. Engonoceras serpentinum (Cragin) \
. Engonoceras pierdenale var. commune isa!
. Engonoceras subjectum Hyatt
5. Engonoceras subjectum eat
. Engonoceras gibbosum Hyatt !
. Engonoceras complicatum Hyatt!
. Metengonoceras inscriptum Hyatt/
. Placenticeras syrtale (Morton)
ILLUSTRATIONS.
Metoicoceras whitei Hyatt
Metoicoceras acceleratum Hyatt
WGondicaesvdanalsheaa i.
Vascoceras hartti Hyatt
Metoicoceras swalloyi (Shumard )
Metoicoceras gibbosum Hyatt
Metoicoceras kanabense Hyatt b Sooteras Gaeta eve Done aes aoe ene eaeS
Heinzia matura Hyatt
Heinzia provincialis (d’Orbigny) |
Heinzia provincialis (d’Orbigny )
Knemiceras syriacum (yon Buch)
Knemiceras compressum, Hyatt
Knemiceras compressum var. subcompressunt
Knemiceras compressum Hyatt
. Subpulchellia castellanensis Hyatt
8. Nicklesia dumasiana Hyatt
2, Pulchellia ‘compressissimal (d/Orbiony)ee- eee eee ce ee eneeeee eee
5. Knemiceras attenuatum (Hyatt)
20. Protengonoceras gabbi (B6hm)
. Knemiceras gabbi Hyatt
. Engonoceras belviderense (Cragin) 7-.-.---------- SeW. eeorteaeeee
. Protengonoceras planum Hyatt
3. Engonoceras uddeni (Cragin)
. Engonoceras serpentinum (Cragin) )}-.-.-----------2----2--+-----= so
7. Engonoceras retardum Hyatt
3. Engonoceras pierdenale (yon Buch)
5. Engonoceras gibbosum Hyatt)
. Engonoceras stolleyi BOhm | OR ae Seaport. ih on ements
. Engonoceras stolleyi Bohm \
- Neolobites choffati Hyatt \
. Metengonoceras inscriptum Flyatt
7. Metengonoceras ambiguum Hyatt eee ees ee eeen= ease eee eee ee
. Metengonoceras acutum Hyatt
Figs. - 1, 2.
. Metengonoceras dumbli (Cragin)
Metengonoceras acutum Hyatt
. Placenticeras syrtale (Morton)
Prare XOXDX.
NEXOX,
O00.
XXXII.
DOO. HUF
XXXIV.
SOK.
XXXVI.
SOXEX VII.
XXXVI.
SOX.
XL.
X LI.
XLII.
XLII.
XLIV.
XLV.
XLVI.
XLVII.
ILLUSTRATIONS.
Figs. 1-4. Placenticeras guadalupze (Roemer) ...--...---------
Figs. 1-3. Placenticeras sancarlosense Hyatt .........-..--..--
Figs. 1,2. Placenticeras sancarlosense Hyatt)
3-5, Placenticeras newberryi Hyatt (Siew haan oe ole &
Placenticeras sancarlosense var, pseudosyrtale Hyatt
Figs. 1. Placenticeras sancarlosense var. pseudosyrtale Hyatt)
2-4. Placenticeras planum Hyatt J
Hips 3. blacenticeras'planum) Ely att. 2s.ossesescce seas eete ae
Figs. 1,2. Placenticeras intercalare Meek ............-------.-
Figs. 1-5. Placenticeras intercalare Meek ............--.------
Figs. 1-4. Placenticeras intercalare Meek ........---.---------
Figs. 1. Placenticeras intercalare Meek }
2, Placenticeras intercalare var. costatum Hyatt] ~~~
Figs. 1,2. Placenticeras intercalare var. costatum Hyatt)
3-6. Placenticeras placenta (DeKay ) areas
Figs. 1,2. Placenticeras placenta (DeKay ) \
3-7. Placenticeras stantoni var. bolli Hyatt!
Figs. 1-7. Placenticeras stantoni var. bolli Hyatt............--
Figs. 1,2. Placenticeras stantoni var. bolli Hyatt
Figs. 1,2. Placenticeras stantoni var. bolli Hyatt)
3-11. Placenticeras pseudoplacenta Hyatt ledcam erste ev i>
Figs. 1-3. Placenticeras pseudoplacenta Hyatt
Figs. 1,2. Placenticeras pseudoplacenta var. occidentale Hyatt)
3-16. Placenticeras whitfieldi Hyatt f
Bigs: 1,2. Placenticeras whitfieldi Hyatt +--25: 22222-22222. ---
Figs. 1-4. Placenticeras whitfieldi Hyatt
. Placenticeras
whitfieldi var. tuberculatum Hoa
3. Placenticeras spillmani Hyatt
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ED LT O RS: ByRsEyReAy ore
Soon after Professor Hyatt’s lamented death, January 15, 1902, it
was the writer’s sad duty, as a representative of the United States Geo-
ological Survey, to examine all the paleontological collections and manu-
scripts in Professor Hyatt’s house in Cambridge, in order to take possession
of those belonging to the Survey. The manuscript of the present volume
was on his desk and contains the results of his last work, in which he was
actively engaged on the day of his death. Fortunately it was almost
ready for the printer, and although the careful reading of the manuscript
to determine the author’s exact meaning and intentions has consumed con-
siderable time, the changes, either in arrangement or in wording, and the
additions that have been found necessary are very few indeed. These
changes are all indicated in their proper places by footnotes or bracketed
statements signed by the editor’s initials, except the unimportant verbal
change of ‘“Cretacic” to “Cretaceous,” made for the sake of conformity
with Geological Survey usage. In his recent writings Professor Hyatt
consistently followed the International Geological Congress rule of ending
names of all periods and systems with ‘‘ic.”
The preparation of this work occupied a large part of Professor
Hyatt’s time for several years. As early as 1897 a manuscript with the
same title was submitted to the Director of the United States Geological
Survey for publication, and soon afterwards the preparation of the illustra-
tions was begun. A copy of this original manuscript now in my hands
shows many important differences in arrangement, classification, and
nomenclature from the later manuscript, indicating that it had been
thoroughly revised and recast in connection with a restudy of the fossils.
Although there are some minor inconsistencies, and there would doubt-
1
12 EDITOR’S PREFACE.
less have been some other changes and additions if the author had lived to
see the work through the press, it is believed that as now published it
fairly presents his latest views. The illustrations were all made under Pro-
fessor Hyatt’s supervision, except a few, which were definitely selected and
indicated by him, and most of which are copies of published figures. He
had also mounted the figures on the first twenty plates and had written the
descriptions of nineteen of the plates. The other figures were nearly all
labeled with specific names. The manuscript was in two packages, one of
which began with the ‘‘General remarks,” followed by Pulchelliidze, Knemi-
ceratidse, Engonoceratidee, and Placenticeratidee, which is nearly the
arrangement of the original manuscript of 1897, while the second package
began with Mojsisovicsiidee and ended with Coilopoceratidee. The plates
arranged by the author contain all the illustrations except the Placenticer-
atidee and a part of the Engonoceratidze. By transferring the introductory
“General remarks” from one package to the other and then uniting the
two packages the descriptions fell into practically the same arrangement
that was adopted for the figures, and which evidently represented the’
author’s latest views as to their relationships. The assignment of the fami-
lies to higher groups was not fully carried out by Professor Hyatt, and it
is thought best not to attempt to complete it, in view of the fact that his
opinions as to the definition and limits of the different superfamilies evi-
dently were much modified, though never formulated, after the publication
of his chapter on Cephalopoda in Zittel’s Text-book of Paleontology. In
that work he divides the Ammonoidea into several suborders, and between
these and the families there is another unnamed category of groups, which
may be called superfamilies, such as Mammitida, Cosmoceratida, ete,
Part of the Pseudoceratite families are there referred to Mammitida, part
to Placenticeratida, the Pulchelliidae were accidentally omitted, and other
families were not there described. In the present paper a list of the fami-
lies belonging to the Mammitida is given, but beyond that group the clas-
sification is doubtful. In connection with the deseription of Vascoceras,
Cosmoceratida is mentioned in such a way that the reference of the genus
to that group may be inferred, and later in the manuscript the heading
Mantelliceratida is inserted, but there is nothing to warrant the assumption
EDITOR’S PREFACE. i}
that the latter term was intended to include Heinziidee, Pulchelliidee, Knemi-
ceratidee, Engonoceratidee, and Placenticeratide. In the published work
above referred to, the two families last named are united with Spheno-
discidee to form the Placenticeratida, but with the removal of Sphenodis-
cide to Mammitida it seems probable that the superfamily Placenticeratida
was abandoned.
The multiplication of families, genera, and species will be understood
by all who are acquainted with Professor Hyatt’s habit of attempting to
express in the terminology every important fact observed in the course
of his investigations.
In characteristic fashion the author plunges into the midst of his
subject, beginning his introduction with a discussion of the sutural details
of Jurassic ammonites, not tarrying even to define the title of the paper or
to make a formal statement of the problems involved. In a footnote on
page 546 of Zittel’s Text-book, where he first used the term Pseudocer-
atites, he states that it ‘is a descriptive expression for the Placenticeratida
and Tissotidee of the Cretaceous, which are morphic equivalents of some
Triassic genera of the Discocampyli as regards both suture and shell form.
Their origin is traceable, however, to different groups of the Pachyeampyli,
a suborder which appears to have been initiated in the Jura along with the
Leptocampyli.. It is, therefore, improbable that the Pseudoceratites were
directly connected with the Triassic Discocampyli.” In a letter written
December 26, 1901, in response to an inquiry from the Geological Survey
office, he gives the following somewhat more definite statement of the scope
and purpose of the present work: “I am at work finishing a ‘Monograph
of the Pseudoceratites of the Cretacic.” This is an artificial group, inelud-
ing, for convenience of treatment, all the retrogressive genera of the Cre-
tacic that have sutures with simple outlines resembling those of Triassic
cephalopods, formerly included under the name Ceratites. The known
genera described and figured are Buchiceras, Tissotia and its allies, Sphe-
nodiscus, Knemiceras, Hngonoceras, Placenticeras. The aim of this publi-
cation is to give as full treatment as possible of the structure and relations -
of these genera, in order to determine as far as practicable to what groups
among the normal progressive forms they are most nearly related.”
14 EDITOR’S PREFACE.
It was Professor Hyatt’s custom, in citing the authority for a species,
to give the name of the author who first referred the species to the genus
in which it is now retained, instead of citing the one who first proposed the
specific name. ‘Thus he wrote Placenticeras placenta Meek, although the
form was described as Ammonites placenta by DeKay. This is not in
accordance with the rule usually followed by zoologists, and the citations
have been changed so that each specific name is followed by the name of
the original deseriber of the species, with the author's name in parentheses
if the generic reference has been changed.
When the figured specimens were at the Geological Survey in the
hands of the artists, Professor Hyatt requested the writer to examine them
carefully and give him notes and comments as to the localities and horizons
of the specimens from his own collection and from other museums. The
quoted statements concerning various species that appear in the manuscript
were extracted from the notes the writer then forwarded to him.
The appended tabular statement is intended to show the relative
positions of the various marine Cretaceous horizons and formations men-
tioned in the text. It does not imply accurate correlation of American and
European horizons, the line between Lower and Upper Cretaceous being
probably somewhat higher in America than in Europe.
The figured specimens that are mentioned in this paper as belonging
to Professor Hyatt’s private collection have now become the property of
the Museum of Comparative Zoology in Cambridge.
The writer has supplied the table of contents, the formal bibliographic
list, and the descriptions of the plates after Pl. XIX.
T. W. Sranron.
CLASSIFIED LIST OF FAMILIES, GENERA, AND SPECIES.
In the following list all the groups that are deseribed and all the
species that are definitely referred to the genera herem treated are arranged
according to Professor Hyatt’s classific: ation as given in the text. The
purpose of the list is to bring together in compact form for easy reference
the large number of described species that are here referred to new genera.
The classification is incomplete and in some cases probably misleading.
For example, some of the genera under Cosmoceratida are not assigned to
families, and it is very doubtful whether Professor Hyatt intended to place
in Mantelliceratida all the families here arranged under that superfamily,
It is evident that the author's published views concerning that group had
changed, but unfortunately he had written no revised description. It is
therefore necessary to leave the groups classified according to the arrange-
ment of the manuscript without inserting the names of any other super-
families.
I aWe:
MAMMITIDA. Choffaticeras Hyatt.
barjonai.
meslei.
douyillei.
Hemitissotia Peron.
Mousstsovicsiib&.
Mojsisovicsia Steinmann.
durfeldi. | cazini.
batnensis.
BUCHICERATID&. morreni,
tissotizeformis.
3uchiceras Hyatt. djelfensis.
bilobatum. ceadouroensis.
Roemeroceras Hyatt. Plesiotissotia Peron.
michaleti.
gabbi.
syriaciforme. TISSOTIIDE.
attenuatum.
subplanum. Tissotia Douvillé.
tissoti.
PsEUDOTISSOTIIDA. | Subtissotia Hyatt.
inflata.
Pseudotissotia Peron. intermedia.
galliennei. peroni.
tunisiensis. africana.
16 PSEUDOCERATITES OF THE CRETACEOUS.
Metatissotia Hyatt.
fourneli.
robini.
ne rc Sa.
haplophylla.
ewaldi.
auressensis.
slizewiczi.
Paratissotia Hyatt.
grossouyrel.
thomasi.
ficheuri.
serrata.
regularis.
INCERT# SEDIS.
Tissotia cossoni.
globosa.
Heterotissotia Peron.
neoceratites.
SPHENODISCID®.
Indoceras Noetling.
baluchistanense.
acutodorsatum.
Libycoceras Hyatt.
ismaele.
Sphenodiscus Meek.
pleurisepta.
lobatus.
stantoni.
lenticularis.
var. splendens.
var. mississippiensis.
beecheri.
konincki.
binckhorsti.
ubagshi.
rutoti.
siva.
EULOPHOCERATID.
Tegoceras Hyatt.
mosense.
Lenticeras Gerhardt.
andii.
Paralenticeras Hyatt.
sieversi.
Eulophoceras Hyatt.
natalense.
COTLOPOCERATID&.
Platylenticeras Hyatt.
heteropleurum.
pseudograsianum.
gevrilianum.
Coilopoceras Hyatt.
colleti.
novimexicanum.
springeri.
requienianum.
grossouyrei.
Aconeceras Hyatt.
nisum.
Vascoceras Choffat.
hartti.
Tolypeceras Hyatt.
marcousanum.
Barroisiceras Grossouyre.
desmoulinsi.
haueri.
Metasigaloceras Hyatt.
rusticum.
| Pseudaspidoceras Hyatt.
footeanum.
conciliatum.
cunliffi.
crassitesta.
euomphalum.
deciduum.
schliiteri.
Diadochoceras Hyatt.
nodosocostatum.
Pedioceras Gerhardt.
cundinamarce.
caquesensis.
ubaquensis.
Douvilleiceras Grossouvre.
mammillare.
orbignyl.
spiniferum.
Schluetericeras Hyatt.
nodosoides.
vielbanci.
laubei.
michelobense.
Sharpeiceras Hyatt.
laticlavyium.
schlueteri.
inconstans.
Acompsoceras Hyatt.
bochumense.
essendense.
renevieri.
COSMOCERATIDA.
MANTELLICERATIDA.
MANTELLICERATID®.
CLASSIFIED LIST OF FAMILIES, GENERA, AND SPECIES.
Mantelliceras Hyatt.
mantelli.
couloni.
picteti.
vicinale.
ushas.
indianense.
domeykanum.
MeTOICOCERATID®.
Metoicoceras Hyatt.
swallovi.
gibbosum.
whitei.
acceleratum.
HEINZUD2.
Heinzia Sayn.
sayni.
corioli.
heinzi.
hispanica.
pulchelliformis.
provincialis.
matura.
ouachensis.
Carstenia Hyatt.
lindigi.
caicedi.
subcaicedi.
tuberculata.
galeata.
Gerhardtia Hyatt.
galeatoides.
galeatus.
veleziensis.
PULCHELLIID®.
Nicklesia Hyatt.
moltoi.
levyi.
nolani.
lapparenti.
alicantensis. e
karsteni.
lenticulata.
didayana.
dumasiana.
Subpulchellia Hyatt.
oehlerti.
fouquei.
sauvageaui.
castellanensis.
MON XLIV—03——-2
, Pulchellia Uhlig.
nicklesi.
schlumbergeri.
columbiana.
selecta.
hettneri.
changarnieri.
kiliani.
ouachens
compressissima.
Psilotissotia Hyatt.
chalmasi.
mariole.
defforgesi.
reigi.
haugi.
Lophobolites Hyatt.
cotteaui.
KNEMICERATID®.
Knemiceras Bohm.
syriacum.
compressum.
yar. subcompressum.
attenuatum.
gabbi.
uhligi.
ENGONOCERATID®.
Protengonoceras Hyatt.
gabbi.
planum.
emarginatum.
Engonoceras Neumayr.
belviderense.
uddeni.
serpentinum.
pierdenale.
yar. commune.
subjectum.
gibbosum.
stolleyi.
complicatum.
emarginatum.
roemeri.
Neolobites Fischer.
vibrayeanus.
choffati.
peroni.
Metengonoceras Hyatt.
inseriptum.
ambiguum.
acutum.
dumbli.
it
18
PLACENTICERATID A.
Placenticeras Meek.
guadalupze.
sancarlosense.
var. pseudosyrtale.
planum.
newberryi.
syrtale.
var. halei.
intercalare.
placenta.
stantoni.
var. bolli.
pseudoplacenta.
var. occidentale.
whitfieldi.
var. tuberculatum.
spillmani.
telifer.
? fallax.
ebrayi.
| Upper Missouri.
Placenticeras warthi.
memoria-schloenbachi.
depressum.
grossouyrei.
incisum.
milleri.
schliteri.
orbignyanum.
polyopsis.
crassatum.
tamulicum.
pseudorbignyanum.
subtilistriatum.
Diplacmoceras Hyatt.
bidorsatum.
canaliculatum.
'
PSEUDOCERATITES OF THE CRETACEOUS.
INCERTZ SEDIS.
Styracoceras Hyatt.
balduri.
Table of horizons mentioned in this work.
Texas.
[ Hills.
Montana
Fort Pierre.
|
|
|
|
|
|
|
|
|
|
|
/
\
S)
m4]
S|
|||
= ae a
Fort Ben-
ton.
| Colorado
| Dakota.
eCOus
]
Lower Cretac
| Navarro, Eagle Pass.
Taylor, San Carlos.
| Austin.
Eagle Ford.
Woodbine.
Buda.
Grayson.
Main street.
Paw Paw.
Marietta.
Denton.
Fort Worth.
{Duck Creek.
Eee
Denison
Washita
Kiamitia.
Edwards.
Comanche series.
Walnut.
Paluxy.
,Glenrose.
Trinity
|rravis Peak.
Fredericksburg ; Comanche Peak.
Gulf border. | New Jersey. Europe.
Ripley. Manasquan | Danian.
(Upper
marl),
Selma (Rot- | Rancocas
ten lime- (Middle
stone). marl), Campanian.
Monmouth | Senonian,Santonian.
(Lower Coniacian.
marl). ’
Eutaw. Matawan
(Clay marl).
Turonian.
Cenomanian.
Albian, Gault-
Aptian.
Barrémian.
s r Hauterivian,
Neocomian ; f
Valangian.
Berriassian.
PSEUDOCERATITES OF THE CRETACEOUS.
By AupHEeus Hyarr.
GENERAL REMARKS.
So far as I have been able to see, either in figures or in specimens, the
Ammonitinee of the Jura have only one large first lateral lobe, even in highly
involute forms, as demonstrated by the admirable researches of Buckman*
upon Hyperlioceras discoidum, subdiscoidum, ete., and the same has been
shown by Oppel’s figures’ of Newmayria discus, hochstetteri, and aspidoides,
and Quenstedt in Amm. truelli,’and the similar hollow-keeled forms alsoin Neu-
mayria serrodens (pls. 24, 69), Polyplectus discoides, and capellinus (pl. 53),
which have a very deeply divided and double first lateral, and in Newmayria
discus (pl. 57) in which there are apparently two or three principal laterals, but
in the neanic stage only one bifid first lateral The Arietidze seem to have
two principal saddles owing to the great development of first auxiliary, but
this occurs only in the ephebic stage. Aspidoceras and some forms of other
genera often have two well-divided principal lateral saddles, but this again
occurs through the late division of the primitive lateral.
In fact, it may be confidently stated that in the Jura all of the Ammo-
nitine have but one principal lateral saddle throughout the neanic stage,
and when, as very rarely occurs, two or three principal laterals are either
apparently or actually developed, they occur as purely secondary, or rather,
tertiary developmental changes in the ephebic stage.
This fact is of importance because of its bearing upon the biology of
Ammonitine in the Cretaceous. With regard to these, it may be stated
that they are distinctly tachygenetic or accelerated in development when
«Inferior Oolite Ammonites: Palzeont. Soc., Vol. II, pp. 40-49.
» Pal. Mittheil., pl. 4.
¢Amm. d. schwib. Jura, pls. 24, 69.
19
20, PSEUDOCERATITES OF THE CRETACEOUS.
.
compared with the Ammonitinz of the Jura. All of the forms so far inves-
tigated, which have more than one principal lateral saddle and lobe, acquire
these characters a stage earlier than the Jurassic species. They appear, as
stated above, in the neanic stage and are secondary modifications of the
outlines of the primitive first laterals of the nepionic stage.
The same law seems to hold in a modified way for the development of
an extra number of auxiliary lobes and saddles such as appear in Neumayria,
but my materials have not enabled me as yet to follow this out. This
statement appears at first sight to be antagonized by that made with
reference to the arrested development of the sutures in genera like
Protengonoceras, Engonoceras, ete., which have undivided or bifid saddles
and lobes only slightly digitated at their extremities. But it will be shown
in the generic description of Placenticeras that the arrest of development
takes effect in these Pseudoceratites of the Cretaceous only after the
three principal lateral saddles and lobes are formed in the neanic stage.
Consequently, up to this stage, the development is more complex than in
the young of Jurassic species or any others which have only one principal
lateral at the same age. This statement clears up the extraordinary relations
of these forms to their apparently more complicated allies of the Jurassic,
and accounts also for the apparent discrepancy existing between the highly
involute compressed character of the whorls during the neanic stage and
the very simple aspect of the lobes and saddles; that such highly involute
compressed forms in the Jura, usually combined with the development of
highly complex lobes and saddles, has been recorded by me in other papers
and by many other writers; consequently, when one meets the Pseudocera-
tites of the Cretaceous he is apt to imagine them to be what Barrande has
called ‘“anachronisms,” and difficult problems for the evolutionist. They
are unquestionably difficult, but they are no more anachronic than any of
the forms usually named as having this paradoxical character. They are
simply excellent examples of arrestation of development taking effect
locally and upon. certain structures. These, if I have rightly understood
the researches of my deceased friend, Professor Cope, the most brilliant
investigator and profoundest thinker on evolution that America has pro-
duced, are good examples of his law of retardation in development, and
also excellent examples of the different way in which I look upon the same
phenomena. I have never regarded such cases as examples of a tendency
GENERAL REMARKS. 21
to retardation of development. A distinction exists between arrestation
and retardation in development, which is of great importance. Arrest of
development occurs in many ways. It may take effect locally, as upon the
sutures, stopping them from developing in complexity of outline beyond a
certain measure, and thus retaining a semblance to their own young and
apparently reverting to the condition of the same parts in more ancient
animals of their own stock. It may take effect upon the whole organism,
as in Baculites and other uncoiled forms, apparently causing the entire
animal to revert in its characters to a primitive form. There are innumer-
able degrees between these two extremes which it is not necessary nor
appropriate to mention here. Retardation is distinet from these and of
much rarer occurrence. “
The development can not be said to have been retarded in these
retrogressive forms, since it begins and for a certain period in the ontogeny
progresses in parallel lines with the ancestors of the group, but passes
through the modifications more quickly according to the law of tachy-
genesis. After this its progress is quite suddenly and decidedly arrested,
and the succeeding stages are no longer parallel with those of their
ancestral forms. The complexity of the outlines of the lobes and saddles
in species of Engonoceras, for example, does increase even in the later
stages; but this increase is very slight, and the result is a retrogressive
form that mimics to a certain extent primitive forms among Goniatitinze
and Ceratitine. Such examples may, nevertheless, belong to the highly
accelerated class, as is shown by the earlier development in these Pseudo-
ceratites of the Cretaceous of the three principal saddles that only appear
in the ephebic stage of the highly progressive forms among Ammonitinze
of the Jura. Retardation of development certainly does not take place
in their early stages. Can it be said to take place because they do not
subsequently proceed to develop numerous marginal lobes and saddles on
the borders of these same lobes and saddles?
Retardation of development can mean but one class of phenomena, viz,
those cases in which a character appears in the ontogeny of descendants
later than the stage at which it appeared in the life of their ancestors. In
cases of retrogression such as are noted above, and in all examples of this
class with which I am acquainted, the complication of the lobes and
@Bioplastology and related branches of biologic research; Proc. Boston Soc. Nat. Hist., Vol.
XXVI, p. 79, ete.
22 PSEUDOCERATITES OF THE CRETACEOUS.
saddles by the addition of marginals during the later stages of the ontog-
eny does not occur; the inexact parallelism is produced by the dropping
out of this stage completely, not by its later and later development.
Cope, in his great work Origin of the Fittest, writes as follows:*
* * * ‘The acceleration in the assumption of a character, progressing more rap-
idly than the same in another character, must soon produce, in a type whose stages were
once the exact parallel of a permanent lower form, the condition of inexact parallelism.
As all the more comprehensive groups present this relation to each other, we are com-
pelled to believe that acceleration has been the principle of their successive evolution
during the long ages of geologic time.
Each type has, however, its day of supremacy and perfection of organism, and
a retrogression in these respects has succeeded. This has, no doubt, followed a law
the reverse of acceleration, which has been called retardation. By the increasing
slowness of the growth of the individuals of a genus, and later and later assumption
of the characters of the latter, they would be successively lost.
To what power shall we ascribe this acceleration, by which the first begin-
nings of structure have accumulated to themselves through the long geologic ages
complication and power, till, from the germ that was scarcely born into a sand
lance, a human being climbed the complete scale and stood easily the chief of the
witole tas
Acceleration signifies addition to the number of those repetitions during the
period preceding maturity as compared with the preceding generation, and retarda-
tion signifies a reduction of the numbers of such repetitions during the same time.’
Thus, from Cope’s point of view, tachygenesis is the law of progression,
and retardation is the law of retrogression, and they are both essential parts
of his law of acceleration and retardation.
These quotations show that we both have the same conception of
the proper use of the word “retardation,” but we differ in the application
of it. He applied it to such cases as are described here among Pseudo-
ceratites, whereas I regard these as true arrests of development and not as
retardations.
Retardation is exceedingly rare among Ammonitine, and as a rule in
other parts of the animal kingdom, and the only examples I am able to cite
are like those given below in Placenticeras, where the more complex species
like whitfieldi, that are obviously descended from species like P. syrtale,
have apparently the nodes and ornaments smaller and developing, as a rule,
later than in that species, and finally, in extreme forms like those of typical
whitfieldi, disappearing altogether.
aPp. 142. bP. 182.
GENERAL REMARKS. DB)
As a rule, among Ammonitinz the reverse is the case, and the disap-
pearance of characters takes place through the earlier and earlier develop-
ment and shorter and shorter life history of each characteristic, or through
tachygenesis, as stated and illustrated in many of my papers. Here I have
space only for one quotation, which will serve to show my meaning more
plainly:
Specialization by reduction of parts is evidently included under the head of
retardation by Cope; thus in Origin of the Fittest (p. 353), he says that ‘* change of
structure during growth is accomplished either by addition of parts (acceleration) or
ss
by subtraction of parts (retardation) So far as my experience goes, in the major
number of cases the parts or characters that are undergoing reduction disappear
according to the law of tachygenesis. They reappear in the: ontogeny at earlier
and earlier stages, or exhibit this tendency in the same way as characters of the
progressive class, but their development is not so complete as in ancestral forms. In
this sense they can be regarded as retarded or thrown back in their development.
There is, however, another way of formulating the expression of this. Instead of
regarding this disappearance by retrogressive gradations as due to a tendency
opposed to acceleration, is it not a tendency of the same kind? That is to say, do
not the parts and characters show a tendency to disappear earlier and earlier, and are
they not in most cases at the time of disappearance present only in earlier stages of
growth than that in which they originated in ancestral forms?
Is not the case of the wisdom teeth exceptional? The frequently extremely late
external appearance of these is not accompanied by a later origin of their rudiments
in the jaw. Although they may not appear in many cases above the gum until a
person is past fifty, is not this real retardation due primarily to the fact that they are
deficient in growth power (tending to disappear from disuse, etc.), and secondarily to
their internal position? When they cease to be able to break through the gum will
they not still continue to develop at the same stage as the other teeth, and will not
their rudiments be likely to be present at this early stage long after they have ceased
developing into perfect teeth ?7
The whalebone whales are examples of this kind so far as the teeth are
concerned, although here the disappearance is correlated with the develop-
ment of whalebone from the rugze ef the roof of the mouth. Nevertheless
the suppression of the teeth in full-grown animals does not take place by
later and later development, and the rudiments of the teeth are still present
in the early stages.
@ Bioplastology: Proc. Boston Soc. Nat. Hist., Vol. XX VI, note to p. 80.
SYSTEMATIC, DESCRIPTIONS.
IMAC MEMEn San) Ac?
This group in my chapter on Cephalopoda in Zittel’s Text-book con-
tained a number of keeled families, in which either the keel was preceded
by a median line of tubercules, or, if this stage were omitted, the smooth
keel arose upon the venter in forms that were apparently closely allied to
the more primitive genera having these tuberculated keels. The Mam-
mitida included Mammitidee, Peroniceratidae, Prionotropidee, Hystato-
ceratidee, Lenticeratidee, and Tissotiidee. To these I propose to add now
the Mojsisoviesiidee, Buchiceratidae, Pseudotissotiidee, Eulophoceratidee, Sphe-
nodiscidze, and Coilopoceratidee.
MOJSISOVICSIIDAE Hyatt.
The single genus and species described below can not be even pro-
visionally included in any of the groups to which it is supposed to be
nearly related, and the following discussion of its generic affinities shows this
conclusively. The dorsal sutures are not yet known, and this is the only
defect in the evidence that establishes it as an independent group, probably
belonging to the parent stock or stem of the Pachycampyli.
MOJSISOVICSIA Steinmann.
The interesting species used as the type of this genus has a form
which is similar to that of Agassiceras of the Lower Lias in being smooth
and diseoidal, with flattened sides, narrow umbilical zones and rounded
venter. The section is what I have called helmet shaped, like Agas. striar-
wes. It differs in having no raised line or keel, and therefore comes a little
nearer to Psiloceras. The sutures bear a similar interpretation, since,
although these are very immature, there are four lateral bifid saddles with
“A penciled note at the top of this page of manuscript says ‘‘ Revise list.” Just what changes
the author would have made can not be known, but it may be inferred that Lenticeratidse was
dropped as an abandoned family, and that possibly Coilopoceratidee was assigned to another super-
family. It is obvious that his conception of the group Mammitida had become yery different from
that expressed by him in Zittel’s Text-book.—T. W. 8.
24
MOJSISOVICSIID. 2D
subphylliform marginal saddles and excessively short pointed marginal
lobes that are hardly more than serrations. The ventral lobe is very broad
and divided. The first and second lateral lobes are narrow and. similar to
those of Buchiceras, but it should be noted that the dorsal sutures are
unknown, and these may be quite distinet. The third lateral lobe is entire,
and the fourth saddle hardly past the entire stage, exhibiting only a slightly
trifid outline. Such sutures exhibit affinities with the smooth primitive
ancestral stock of the Psiloceratide of the Jura and other forms of Pachy-
campyli descended from these because of their massive broad saddles, so
entirely different from the narrow, excessively branched saddles of the
Phyllocampyli and Leptocampyli. 1 do not, of course, mean that Mojsiso-
picsia 1s probably descended directly from Psiloceras, but it may be a Cre-
taceous member of a primitive stock which began with Psiloceras in the
Jura. The intermediate forms are as yet unknown or have not been pub-
lished. The existence of such a trunk or main branch of a primitive stock
from which all of the more complex groups are lateral offshoots has been
inferred from the ontogeny as the most probable way to account for the
ontogeny of the primitive species of these groups. Thus in the present
‘stance the smooth discoidal young of Buchiceras and other genera can be
readily accounted for if the comparison between them and the later stages
of Mojsisovicsia is admitted. If such a stock of primitive forms existed, it
is also easy to account for the maintenance of such primitive smooth psilo-
ceran-like shells in the later nepionic and sometimes in the neanic stages of
Cretaceous forms. Otherwise the continued renewal of these in the ontog-
eny at such late stages must be referred to more ancient ancestors than any
represented in the Jura.
MoysIsoVICSIA DURFELDI Steinmann.
Pie hesselo-
Mojsisoviesia durfeldi Steinmann, Neues Jahrbuch fitr Min.. Geol., und Pal., 1881,
11, p. 143, pl. 6.
The peculiar fossil described under this name has a compressed discoidal
shell with slight constrictions, open umbilici, and smooth surface that im
external aspect resembles Traneceras and also some of the diseoidal Desmo-
ceratidee like Pseudophyllites Kossmat, but has entirely different sutures.
These have an aspect similar to those of Buchiceras bilobatwn, but the form
of the volution differs so widely that no further comparisons can be made
26 PSEUDOCERATITES OF THE CRETACEOUS.
.
with this genus. The living chamber is short, the aperture has a blunt
rostrum, there are shallow sinuses on the edges of the venter, a broad
lateral rostrum on either side, and shallow sinuses between these and the
umbilical shoulders, and probably a crest on the dorsum.
The ventral lobe is very broad and short, with a broad short siphonal
saddle. There are three bifid lateral saddles, with an incomplete apparently
entire saddle at the line of involution. The lobes are short and much
narrower than the saddles, and the entire outlines of both lobes and saddles
have short obtuse marginal saddles and narrow, short, pointed, simple
marginal lobes.
The species is known to me only through Steinmann’s figures, which
are reproduced on PI. I, figs. 1-3, with the single exception of his enlarged
drawing of the side view of fig. 1.
Locality: Pariatambo, Peru.
Age: Albian (°?).
BUCHICERATIDA Hyatt.
It has been found impracticable to unite the genus Buchiceras with any
known family, on account of its peculiar development and sutures. The
approximation to the Hystatoceratidze is close, so far as the earlier stages
are concerned, the compressed, comparatively smooth-keeled young in the
neanic stage having considerable resemblance, but these similarities are lost
in the subsequent development, owing to the partial suppression of the costee
and the very distinct sutures. The development and sutures separate these
forms completely from Anemiceras. They are separable from Tissotiidee by
their first lateral saddles and their ventral lobes, and from Barroisiceras,
which they also resemble, by the absence at all stages of a third line of
tubercles and by their sutures.
The sutures are similar to those of the discoidal smooth shell of uncer-
tain affinities described as Mojsisovicsia by Steinmann.
So far as known there are no representatives of this genus except in
South America. It should be remembered, however, that all information
heretofore published has come from this single fossil.
The second genus included in this family, Raemeroceras, has similar
ventral lobes and siphonal saddles, and the young, although quite distinet
in being less compressed in the early stages, acquire a similar keel at a
later age, and similar form and ornaments.
BUCHICERATID A.
bo
“I
BUCHICERAS Hyatt.
This genus was formerly described by myself as including several
different species that have since been separated into distinct genera, by
Douvillé, Grossouvre, and others, and by myself, in Zittel’s Text-book of
Paleontology. The affinities of Buchiceras are not, in my opinion, very
close to any of the forms formerly referred to Acanthoceras as supposed by
some authorities. The sutures are quite distinct from those of any of the
families of Mammitida on account of the extraordinary breadth of the second
lateral saddles. The development is similar to that of some forms of Hys-
tatoceratidee and Peroniceratidee in that it is at first discoidal, compressed,
and smooth, then keeled, becoming costated and tuberculated later, and
the sutures approximate more closely to those of the young of these families
perhaps than to others. Nevertheless the ontogeny differs in that Buch-
iceras does not subsequently acquire prominent costee, and the keel tends to
disappear instead of becoming larger with increase in size of the volutions.
The nodes, on the other hand, increase in size and prominence, especially the
inner row on the umbilical shoulders. The faint serrations on the keel and
other ornamentation suggest affinities with Barroisiceras, but the sutures and
the absence of a third line of lateral tubercles, which appear in some forms
of Barroisiceras, are not favorable to this solution of the affinities. The
same objections apply almost equally to keeled forms of the Prionotropidee
in which the young resemble more or less closely those of B. bilobatum.
The dorsal sutures are very remarkable and perhaps may eventually assist
in placing this genus in closer connection with others. The primitive first
lateral saddle is retained in Buchiceras until a late stage, and perhaps
throughout life; it is undivided, except by small entire marginal lobes, but
it is distinctly bifid.
BUCHICERAS BILOBATUM Hyatt.
Pl. I, figs. 4-9.
Buchiceras bilobatum Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p. 370.
Buchiceras bilobatum Douvillé, 1890, Bull. Soc. eéol. France, 3d ser., Vol. XVIII,
p. 284.
The young, for the first two, and perhaps part of the third volution,
must have had smooth sides and was obviously very discoidal, flat, and
keelless. The aspect of this species must have been very similar to Mojsi-
sovicsia. The keel comes in upon an elevated venter previous to reaching
28 PSEUDOCERATITES OF THE CRETACEOUS.
the diameter of 5 mm. and is faintly sinuous during the latter part of the
volution seen in PI. I, fig. 4. These faint undulations are due to prolonga-
tions of the costee that pass between the tubercles on the ventro-lateral
angles. ‘This keel, which is a mere angle on the venter, was obviously
continuous before the costze appeared and is practically continuous subse-
quently, owing to the minute character of the inflections. Upon the last of
the outer volution at this diameter, the first of the fourth volution, the outer
line of tubercles appears and is connected by costee with the inner line.
The last are very widely separated at first and become nearer only in later
stages. The larger cost at this age are separated by single, arcuate costa-
tions terminated outwardly by minute tubercles and fading out internally
about halfway across the volution. The umbilical zones are not differenti-
ated trom the sides. The side is evenly plano-convex from the keel to the
line of involution and the inner, uncostated part is smooth, except where
interrupted by the inner tubercles or extensions of the tubercular termina-
tions of the larger costae. The tubercles and nodes are opposite, not alternate.
The sutures at this age consist of two large saddles (PI. I, fig. 9), a narrow first
lateral lobe in the center of the lateral zone and a broad second lateral on the
umbilical zone. ‘The inflections are all apparently entire. In succeeding
stages the lobes remain in the same position, there being but one in the
center of the side between the two rows of tubercles and one on the umbilical
shoulder, but as the shoulder becomes more prominent and the umbilical
zone broadens, other lobes and saddles appear internally. The venter
broadens with age, the keel becoming more obscure in consequence of this;
the sides become flat and convergent; and the umbilical shoulders broaden
out more than the venter, the increase in the umbilical zones making the
umbilici very deep. The keel on the cast at this mature stage is faintly
undulated, and the lateral costze, although very obscure, cross the venter
and interrupt the keel between each pair of opposing ventro-lateral nodes.
These widely separated serrations are so faint on the cast that they entirely
escaped my observation on former occasions. They in fact can be felt
more easily than they can be seen. This is also the case in the earlier
stages described above. The inner nodes are always larger and fewer
than those on the edges of the venter. The second lateral saddle remains
broader than the first lateral, even when the shell is somewhat over 40 mm.
in diameter. It occupies a trifle more than half of the side and encroaches
on the umbilical zone (PI. I, fig. 8).
BUCHICERATID 2. PAS)
The ventral lobe is very widely open at the base and longer than the
first lateral lobe. The two arms are blunt and very small. The siphonal
saddle is phenomenally short and broad, with a faint centran marginal lobe
and an equally faint marginal rounded saddle on either side. The first
lateral lobe is funnel shaped, broad at the base, short and narrowing
rapidly to a bifid termination. The second lateral lobe is very much
smaller and shorter, and entire at the end. The third lateral saddle is
small, entire until a late stage, but becoming bifid later. Beyond are two
small entire saddles and two corresponding lobes or what may perhaps be
more accurately described as a bifid lobe and a bifid saddle.
The first and second lateral saddles have internal ridges, but these
coalesce, forming a short, flattened area along the mesal plane, which
becomes deeply convex toward dorsum and venter. There are only two
broad saddles and two narrow lobes on the dorsum, and these have no
connecting ridges with the external saddles. The surfaces of the wings of
the septa are strongly inclined inward, the outer sutures being considerably
in advance or orad of the inner ones. This gives a remarkably concave
aspect to the wings of the septa on either side of the dorsum.
The dorsal sutures, which were worked out with difficulty, show that
the inner arm of the bifid fourth lateral saddle passes across the line of
involution, coalescing with the third dorsal saddle. The antisiphonal lobe
is asymmetrical, entire at the top, unequally. serrated on the sides, and bent
over to the left until the tips touched the inner angles of the first pair of
dorsal saddles to the right of the 1mesal plane of the body. The first pair
of dorsal saddles are deep and broad with broad entire bases. The first
lateral lobes are small and unequally bifid, the sides being coarsely serrated.
The second dorsal saddles are much inclined and obscurely tridentate or
entire. The second dorsal lobe is very small and entire. The third dorsal
saddle is a part of the fourth lateral, as stated above, and is entire.
Vestiges of the shell were present upon this cast in a few places and
showed coarse lines of growth. Unfortunately the shell covering the venter
of the young whorl was chipped off in cleaning this part for drawing, and
evidence of the statement made above with reference to the keel was lost.
Locality: Cachiyacu, west side of Hullagua River, Peru.
Age: Upper Cretaceous.
30 PSEUDOCERATITES OF THE CRETACEOUS.
ROEMEROCERAS Hyatt.
These shells were so similar to the type of Buchiceras in external aspect
that I formerly supposed the type of this genus to be an older stage of B.
bilobatum, but more prolonged acquaintance with these forms shows that
they are not in the same generic group. While the bifurcated costee, the
large nodes on the umbilical shoulders, and the nodes on the ventro-lateral
angles are the same, the involution is greater, the lateral zones more com-
pressed and broader, the umbilici narrower, the young have larger nodes,
and the keel entirely disappears in the full-grown shells, except perhaps in
R. gabbi. The sutures are also quite distinct, and similar to those of Tisso-
tide in some species, but the first lateral saddles tend to develop three arms
in some species and the bases of the other saddles are apt to be dentated
more or less completely. The ventral lobes are similar to those of Buchi-
ceras and entirely distinct from the broad ventrals of the Tissotiidee. The
same characters appear to unite Anemiceras with Roemeroceras, but the
development and full-grown shell in A‘nemiceras, especially the invariable
presence of the concave venter, seemed to place it in closer association with
the Pulchelliidee.
ROEMEROCERAS GABBI n. sp. Hyatt.
Pl. U, figs. 1-3.
Ammonites bilobatus Gabb, 1877, Jour. Acad. Nat. Sci. Philadelphia, 2d ser., Vol.
VIL, p. 270, pl. 38, fig. 3.
In my revision of this form I made too great allowance for the possible
variations due to age, and misled Professor Gabb in identifying this fossil
with Buchiceras bilobatum. As compared with B. bilobatum, the nodes on the
umbilical shoulders are much less prominent and more numerous and more
closely approximated, the venter has large ridges not present in bilobatum,
and the flatness and proportions of the saddles are too distinct to occur in
the same species, even though allowance be made for the sutures in gabbi
being nearly one volution older than those examined in B. bilobatum. The
sutures of this species approximate more closely to those of R. syriaciforme
than to those of any other species, but &. gabbi differs in the greater number
and smaller size of the nodes and coste. Fig. 3 of Gabb’s plate shows the
lateral aspect with an outer line of nodes lower on the sides and a sinuous
outline to the venter which does not appear im syriaciforme, and also a
BUCHICERATID A. 31
stouter and more quadragonal volution than any other species of this genus.
The originals of this species were not reexamined. They could not be
found in the Academy’s collection at the time of my visits, nor has subse-
quent search, made by the kindness of Professor Pilsbry, brought them to
light.
Locality: Quebrada de Colpamayo, Department of Cajamarea, Peru.
Age: Upper Cretaceous.
ROEMEROCERAS SYRIACIFORME Hyatt.
P]. I, figs. 10-14.
Roemeroceras syriaciforme Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII,
p- odd.
This species reaches a diameter of 90 mm. in one east without a living
chamber. The sutures are approximated and overlap internally on the
auxiliaries, showing that the gerontie stage has begun. The ornamentation
and form are the same as in bilobatum. When the cast is only 29.5 mm. in
diameter there is, however, no difficulty in separating this from bilobatum.
It is more compressed, the sides broader, the venter narrower and flatter.
The sutures have more resemblances to those of R. gabbi, but the saddles
and lobes are never so short, nor truncated, the saddles being narrower and
the lobes broader. The ventral lobe and siphonal saddle are similar, but
narrower and less digitated. he first lateral saddles are similar in being
bifid and rather broad, but already at this early stage show denticulations
over the entire base. The first lateral lobe is similar but less deeply divided,
by the similar rnarginals. The second lateral saddles are unequally bifid
with bases rounded or approximately phylliform, entire, and unlike those of
gabli. The second lateral lobes are quite broad, apically like the first
laterals, but are unequally quadrifid. The third lateral saddle is as broad
as the second lateral, and also bifid. It occupies part of the side and also
part of the umbilical zone, the marginal lobe being upon the umbilical
shoulder. Inside of this there is one broad bifid saddle reaching to the
lobe at the line of involution. There are therefore four saddles at this early
stage very like those of gabbi, except in having rounder bases. Later, on
the same volution, this inner saddle becomes divided into two by a median
marginal lobe, and still later a small lobe makes its appearance at the line
of involution, completing the outline of the innermost lateral saddle.
There are then five saddles and six zygos lobes on either side.
314 PSEUDOCERATITES OF THE CRETACEOUS.
The oldest sutures are very much changed, and look like those of a
distinet species, but are obviously in the gerontic stage. The bases of the
saddles are nearer together, the entire parts of the sides much elongated,
and the lobes longer and narrower and the digitations situated at their
apical ends much deeper. The saddles are longer and broader, with entire
bulging sides, and the marginals not increased in number, but much longer
and larger.
The sutures have at this stage close similarity to the peculiar outlines
attributed to Ammonites syriacus by von Buch (fig. 1 of pl. 7 in his Uber
Ceratiten), but the first lateral is not so broad and does not have the minute |
phylliform marginals of that figure. The marginals on the first lateral
saddles, and also in the first lateral lobe, are tongue shaped.
The fourth and fifth lateral saddles are entire, tongue shaped, and
divided by a narrow bifid lobe. The young sutures, until a late neanic
stage, have outlines similar to those of some species of T%ssotia. After this
the outer saddles become completely denticulated, and again, as described
above, lose a considerable part of these denticles in old age.
Fragments of the shell were present on the largest cast. None of the
specimens was incrusted by any extraneous growths that could be shown
to have fastened themselves on the surfaces of the casts.
The figure of the young in an early ephebic substage (PI. I, fig. 12) is
a very near approach to the old specimen which was crushed on one side
(PI. I, fig. 10), but of course, owing to differences of age, the nodes ‘are
larger. There are fifteen nodes on the ventral border and six on the
umbilical shoulders on one volution of the younger specimen, and eleven
on the outer and seven on the inner row of the old specimen. The bifid
coste are also present in the younger specimen, mingled with single ones,
as in the old stage. The keel disappears on the last quarter of the outer
volution, both on the cast and on the shell, in the young specimen, and is
absent also in the older one. The young shell was seen in a section of the
specimen represented by fig. 12 of PL I, and although not perfect enough
to figure, showed that when about of the same size as the young of B.
bilobatum (Pl. I, figs. 5, 7), it had a similar keeled form.
Locality: Cajamarca, Peru.
Age: Upper Cretaceous.
“See also description of R. attenwatwm Hyatt.
BUCHICERATID.E. 33
ROEMEROCERAS ATTENUATUM (Hyatt).
PI. I, fig. 15.
Buchiceras attenuatum (pars) Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII,
p. 372.
The cast differs from syriaciforme in having more numerous nodes on
the inner line. On the outer volution, at a diameter of 64 mm., there are
about nine on the inner row and sixteen on the outer, whereas in syriaci-
JSorme, at a diameter of 90 mm. there are seven on the inner line and eleven
on the outer line; in another specimen of syriaciforme, at a diameter of
73 mm., there are the same number; in another, at a diameter of 34 mm.,
there are six on the inner and fourteen on the outer line; in another, at a
diameter of 41 mm., there are seven on the inner line and fifteen on the outer.
There are faint signs of a keel on the type specimen, showing that it
belongs in this genus. The general form is much more compressed than
that of R. syriaciforme ; the venter is narrower and the keel is also less devel-
oped. The volutions are more enveloping, and the umbilicus is smaller.
The specimen is a cast, partly crushed on one side and somewhat worn on
the other, but although the sutures are not consequently perfect they are
entirely distinct from those of other species. The first lateral lobes are bifid
and shorter than the ventral lobe. Instead of being of about the same
length or longer than the ventral, as in &. syriaciforme, all the saddles are
broad and very short, as are also the lobes. he first lateral.saddles and
lobes are completely denticulated by marginals. The second lateral is trifid,
the third and fourth saddles are bifid, and there is a fifth saddle, but this is
on the line of involution and very narrow. The second lateral lobes are
trifid. The third lobe is in the umbilical zone and bifid, but otherwise entire,
and the fourth is very small and apparently entire, but too much worn to
make observation certain.
There are incrusting ostreans upon both sides of this cast and they
appear to have been attached to a fossil cast.
This species is founded upon a single fossil cast, one of the two used
for the description of Buchiceras attenuatum Hyatt, but not the type. The
latter is to be found on page 151, under the name of Anemiceras attenuatum
Hyatt.
Locality: Celendin, Peru.
Age: Upper Cretaceous.
2
MON XLIV—03——3
34 PSEUDOCERATITES OF THE CRETACEOUS.
ROEMEROCERAS SUBPLANUM DN. Sp. Hyatt.
Pl. I, figs. 4-6.
This specimen is a cast, whole diameter 55 mm The lateral zones
are flatter than in R. syriaciforme and denticulatum, and the outer nodes are
smaller, more acute, and have slight ridges or orad continuations in some
eases. The inner nodes are also smaller in the young and increase very
rapidly in size on the last volution and then suddenly disappear, the volution
becoming at the same time contracted to a subquadrate outline. There
are four small and three large nodes on the inner line, the place where the
fitth node ought to be is vacant, and there are fifteen nodes on the outer
line. The living chamber, which is probably very nearly complete, is less
than one-half of a volution in leneth The last two large nodes of the
inner line are on this chamber.
The sutures have very broad, short, simple saddles and very short
lobes. They are similar to those of &. denticulatum but have not such
complex outlines. The last six sutures are nearer together and become
finally closely approximated, showing that the fossil is probably an out-
grown shell. This cast having been cracked open, it was possible to study
exactly the contact of incrusting ostreans with the surface. It was found,
as in other cases described, that no shell layers were present, the ostrean
having grown directly upon the surface of a fossil cast. The shelk is
present in the impressed zone where it is protected by the enveloping
volutions, and it is there thick and well defined.
Locality: ©
Age: Upper Cretaceous.
Jajamarea, Peru.
PSEUDOTISSOTIID Hyatt.
If the position here taken is correct, the genera assembled under this
hame are distinet from those heretofore included under the Tissotiidee
They include forms from the discoidal channeled and keeled Pseudotissotia
in the Turonian to the highly involute compressed Plesiotissotia of the
Senonian. The lobes have the same denticulated outlines as in Tissotidee,
but the saddles are more complex, being denticulated in all the genera
except Plesiotissotia, in which they are all bifid, the first lateral saddles
bein
g quadrifid according to Peron’s figure.
PSEUDOTISSOTIID_®. 35
The relations of the genera in this family can only be estimated by
their full-grown shells and sutures, and doubtless any arrangement that
can now be made will be only provisional. So far as the facts go,
Pseudotissotia is a flat-ventered, keeled, and channeled form until a late age,
losing its keel in old age and having so close a resemblance to Tissotia
tissoti that it seems to be the only form having any claims to be considered
the ancestor of that species, as first pointed out by Peron.
Choffaticeras, until a late age, has a venter with keel and channels like
those of Pseudotissotia in C. meslei but combined with an inflated volution
and deep, abrupt umbilici and highly inclined, convergent sides. In other
species the line of modifications indicated by the later stages of its ontogeny
oe, and
leads into forms having subacute venters at a comparatively early ag
possibly the keeled and channeled stage with its flat venter may have
altogether disappeared in some of these. The highly involute, compressed-
keeled forms of Hemitissotia follow these in the same line of modification
and as their sutures also coincide and they occur in the Senonian, whereas
all of the above-described genera are Turonian, Peron’s idea that they are
the direct descendants of Pseudotissotia seems to be well sustained.
That these are not transitional to true Tissotia becomes apparent when
P}
it is recognized that the type form of that genus has an ontogenetic history
like that of Pseudotissotia and is probably, as stated in the description of
the Tissotiidze, the most primitive member of a series of forms distinguished
by their differences of development as well as by their simpler and more
retrogressive sutures.
Although the sutures differ decidedly, the forms of more primitive
species like Pseudotissotia galliennei and their keels appear to place them
provisionally nearer to the Buchiceratidee than to the keelless forms. I have
had no fossils for examination in this family, but the literature and the
figures given by Grossouvre and Peron have been sufficient to enable me
to arrange the forms provisionally and to make comments upon their
probable relations that will, it is hoped, attract attention and lead those
who have better opportunities to test the truth of the views presented
below.
PSEUDOTISSOTIA Peron.
Peron’s typical species, Ps. galliennei, is a discoidal form with keel and
channels, having obviously, as observed by Peron, genetic affinities with
36 PSEUDOCERATITES OF THE CRETACEOUS.
.
true Tissotia as here defined, but it differs in the more complex outlines of
the sutures, all of which have small marginal lobes and saddles. In my
opinion, the genus should be limited, so far as known, to one species, the
type described by Peron. The other species described under this name are
obviously widely distinct in their forms and mode of development. The
sutures resemble those of Roemeroceras ou the lateral aspect. The ventral
lobes are also alike, so far as ean be seen on Peron’s figure. Peron’s sug-
gestion that these are the ancestors of Tissotia and its allies in the Senonian
appears to be supported by the facts so far as now known. They appear
also to have been the immediate ancestors of Hemitissotia and its allies in
the Senonian, but this last inference needs confirmation that can only be
obtained through the study of the young of the latter.
PsEUDOTISSOTIA GALLIENNEI (d’Orbigny).
Pseudotissotia galliennei Peron, 1896, Mém. Soc. géol. France, Paléontologie, Vol.
Wale eNovdliepla 2 tion 3 plarosmtocnle
This is a moderately compressed but still comparatively discoidal form,
with large umbilicus and involution enveloping something more than one-
half of the sides, according to Peron’s figures. The venter is flattened,
with heavy, continuous keel and shallow channels bordered externally by
thick continuous ridges. The sides have very broad fold-like coste with-
out tubercles. In extreme age all of these ornaments disappear. ‘The
entire aspect and genetic transformations of this fossil are so similar to
those of Tissotia tissoti that it would have to be included in the same genus,
if the sutures were unknown.
Locality: France.
Age: 'Yuronian.
PSEUDOTISSOTIA ? TUNISIENSIS n. sp. Hyatt.
Tissotia cf. fourneli Peron, 1896, Mém. Soc. géol. France, Paléontologie, Vol. V1.
Now liGepl diz ios (75:
Tissotia fournel’ Peron, 1890, Moll. Crét. de la Tunisie, pl. 17, figs. 11-13.
This remarkable fragment has a truncated venter, entire keel, and
compressed volution, with moderately large umbilicus. The costze are fold-
like, with tubereles on the umbilical shoulders and a line of closely set
elongated tubercles on the ventro-lateral angles. The first lateral saddles
are trifid and rather peculiar, owing to the approximate equality of the three
PSUEDOTISSOTITD. Bill
marginal saddles. The other saddles are very long and phylliform, and
according to Peron’s figures the third saddle is trifid or bifid. These
sutures and the ventral lobe, with its steep denticulated sides and truncated
siphonal saddle, are similar to the sutures of the old stage of Roemeroceras
syriaciforme. ‘The form and ornamentation also agree with this determina-
tion, but the keel is more prominent than is usual in this genus. It is pos-
sible to understand this form, if it is related to Ps. galliennei, because in that
case the keel and lateral coste are similar to those of that species. The
differences in sutures lie largely, according to Peron’s figure, in the second
lateral saddles, which are entire. This may be due to retrogression.
Locality: North Africa.
Age: Santonian.
CHOFFATICERAS un. gen. Hyatt.
This genus has sutures similar to those of Pseudotissotia, but the form
is distinct. The species are more or less stout gibbous forms with more or
less open and deep umbilici. The sides are heavily costated and nodose
along the umbilical shoulders, but there are no external tubercles according
to Peron. He also describes the venter as having a continuous keel and
two ventro-lateral ridges. The form is more involute and more compressed
than Pseudotissotia, and the outer parts of the volutions have a tendency to
become concave in the involute species with broad volutions.
The type is C. meslei (Peron).
CHOFFATICERAS BARJONAI (Choffat).
Pseudotissotia barjonai Chottat, 1898, Faune Crét. du Portugal, Vol. I, 2d series,
pl. 18, fig. 3; pl. 22, figs. 40-42.
This species is a close ally of C. meslet of North Africa, as has been
stated by Choffat, but has a more prominent keel and has no signs of
channels on the venter.
Locality: Portugal.
Age: Turonian.
CHOFFATICERAS MESLEI (Peron).
Pseudotissotia meslei Peron (pars), 1896, Mém. Soc. géol. France, Paléontologie,
Vol. VI, No. 17, pl. 1, fig. 1; pl. 2, fig. 1 (not pl. 2, fig. 2, nor pl. 3, fig. 2).
This species has a form which is sublenticular when seen trom the
front in Peron’s figure, owing to the great prominence of the umbilical
38 PSEUDOCERATITES OF THE CRETACEOUS.
shoulders and the rapid slope of the lateral zones and subacute character
of the venter. The costa are linear and only slightly curved in the only
well-preserved part of his type as figured. The involution covers about
three-fifths of the next inner whorl, leaving a rather large open umbilicus
showing the younger whorls. .
The more discoidal form (pl. 2, fig. 2, and pl. 3, fig. 2) supposed to
belong to this species, is certainly distinct specifically and may be nearer
to Pseudotissotia than to any species of this genus, but it is too imperfect to
give diagnostic characters.
Locality: North Africa.
Age: Turonian.
CHOFFATICERAS? DOUVILLEI (Peron).
Pseudotissotia douvillei Peron, 1896, Mém. Soc. géol. France, Paléontologie, Vol.
VI, No. 17, pl. 2, figs. 4, 5, and pl. 3, figs. 3, 4.
This species, as figured and described by Peron, has the general form
and aspect of C. meslei, but the heavy nodes on the umbilical shoulders
and dichotomous coste reaching to the sides of the prominent keel are
auite different.
Locality: North Africa.
Age: Turonian.
HEMITISSOTIA Peron. :
This genus seems to me to be more intimately related to Choffaticeras
than to Tissotia and other genera having similar forms but having sutures
with smooth saddles. Such questions can only be definitely settled when
the younger stages become known. These involute and more or less com-
pressed forms with trenchant keeled venters are apparently in the direct
line of modifications indicated by the similar forms of Tissotidee, but on
the other hand their sutures correlate with the more complex outlines of
those of Pseudotissotia and Choffaticeras, and this indicates that they are
simply parallel as representative forms analogous to some of the Tissotide
but really in the genetic line of Choffaticeras. hey have retrogressive
characters in the undivided outlines of their inner saddles, but this arrest
of development has not affected the outer saddles that are completely
digitated. They can not be placed anywhere in the genetic line between
Pseudotissotia and Subtissotia on account of the absence of channels and
PSEU DOTISSOTILD.E. 39
ridges on either side of the keel, and this is the only position that could be
claimed for them in view of: their peculiar sutures. All of their characters
accord best with the view that they are direct descendants of Choffaticeras.
There is an interesting group of this or an allied genus from the Senonian,
described by Choffat in his Céphalopodes de la Faune Crétacique du Portu-
gal, Vol. I, 2d series, but the condition of the specimens did not permit
him to describe them sufficiently to judge closely of their affinities.
Hemirissorra CAZINt Peron.
Hemitissotia cazini Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII,
No 17, pl. 14, figs. 1-5; pl. 18, figs. 9, 10.
This species is a highly involute compressed form, and in the oldest
specimen figured the first and second lateral saddles are completely
denticulated, the third is equally divided by a median marginal lobe in the
figure of the suture of the oldest specimen (pl. 18, fig. 9), but this is not
deseribed in the text.
Locality: North Africa.
Age: Senonian.
I ss A’ BATNENSIS Feron.
HeEMITISSOTIA? BATNEN 12;
Temitissotia? batnensis Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol.
Wa INOs dis ple dio, hos. (18.
This species has the external aspect of this peculiar group and the
sutures are similar as figured by Peron, but his question mark after the
generic name is justified by the Sphenodiscus-like aspect of the first lateral
saddles.
Locality: North Africa.
Age: Senonian.
HEMITISSOTIA MORRENI (Coquand).
Flemitissotia morrend Peron (pars), 1897, Mém. Soe. géol. France, Paléontologie,
Vol. VII, No. 17, pl. 15, figs. 1 and 2 only, and pl. 1s, fig. 11.
Hemitissotia morren’ var. precipud, ibid., p. TT.
This var. precipua of Peron is a highly compressed form with acute
venter. Pl. 15, fig. 8, may be the young of this species, and if so, it shows
conclusively that it is distinct from the following.
Locality: North Africa.
Age: Senonian.
40) PSEUDOCERATITES OF THE CRETACEOUS.
HEMITISSOTIA TISSOTLEFORMIS Peron.
Hemitissotia morreni var. tissotieformis Peron, 1897, Mém. Soc. géol. France,
Paléontologie, Vol. VII, No. 17, pl. 15, figs. 8-5 only.
This is a much stouter form with stouter volutions, and as might be
expected in such a species the young exhibits distinct ribs. Hemitissotia
morrent var. coquandi (pl. 15, fig. 6) may be distinct, but no front view is
given and the sutures shown in pl. 18, fig. 14, do not appear to be very
different.
Locality: North Africa.
Age: Senonian.
HEMITISSOTIA DJELFENSIS (Peron).
Tissotia djelfensis Peron, 1897, Mém. Soe. géol. France, Paléontologie, Vol. VII,
No. 17, pl. 16, figs. 3, +.
Buchiceras ewaldi (pars) Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 7 and 9
(no others).
This is a compressed shell very closely allied to Paratissotia fichewri in
aspect, but differing in the sutures. These have the first lateral saddles
narrow and bifid as in Hemitissotia and the first lateral lobe is large as in
that genus. The figure of the highly compressed cast given by Peron as
part of his ewaldi in the Mollusques Crétacé de la Tunisie has very similar
sutures so far as the deep division of the first lateral saddles and lobes is
concerned. It is better to quote it here, since it is undoubtedly not related
to the other species on the same plate and has also a form similar to that of
delfensis.
Locality: North Africa.
Age: Lower Senonian.
HEmMITISSOTIA CEADOUROENSIS Choffat.
Hemitissotia ceadouroensis Choftat, 1898, Faune Crét. du Portugal, Vol I, 2d series,
pl. 20, figs. 7-10.
This species is apparently a member of this genus and is of interest
in showing the old-age transformations, the rounding of the venter and
contraction of the outer volution. If the last part of the last volution is
perfectly natural, it shows an extraordinary senile scaphitoid deviation from
the spiral.
Locality: Portugal.
Age: Senonian.
PSEUDOTISSOTIIDA, TISSOTIID 4. 41
PLESIOTISSOTIA Peron.
This genus has been founded by Peron entirely upon the ditferences of
the sutures as compared with Hemitissotia. The first lateral saddles are
broad and very deeply divided by a median marginal lobe and each arm
is phyllitorm and is also subdivided by a median marginal lobe; the
remaining saddles are phylliform and equally subdivided by median
marginal lobes. It is a question whether these peculiar sutures really
represent another group or are simply retrogressive modifications in the
genetic line of Hemitissotia. ‘The compressed and costated form does not
indicate aftinities, but, as stated by Peron, the divided saddles are similar
to those of Hemitissotia precipua, except the first laterals, which are narrow
and irregular in outline in the latter.
PLESIOTISSOTIA MICHALETI Peron.
Plesiotissotia michaleti Peron, 1897, Mém. Soe. géol. France, Paléontologie, Vol.
VII, No. 17, pl. 16, figs. 7, 8.
A highly compressed keeled form with costee having tubercles on the
umbilical shoulders, as in some species of Hemitissotia. The sutures are
described in the notice of the genus.
Locality: North Africa.
Age: Senonian.
TISSOTIIDAE Hyatt.
This family name is here much narrowed in its application as compared
with what it was in my chapter on Cephalopoda in Zittel’s Text-book. It
is now considered applicable to a series of genera that includes only Tissotia
and its immediate allies, excluding Pulchellia, Psilotissotia and Lopholobites.
The genera can be described as having keeled forms, with channels only in
. FO mn = F .
primitive genera. The keels have a crenulated or nodose stage in a number
of primitive genera, but are continuous in the flattened forms. Costze are
present in the globose primitive forms and are usually tuberculated, and
when they disappear the nodes are apt to persist. The venters lose their
keels and become rounded or flattened in old age. One genus has a hollow
keel (Paratissotia) and others may have hollow keels. So far, however, the
only fact in favor of this is the presence of prominent keels on the shells
that have no corresponding keel elevations on the casts. The sutures are
42 PSEUDOCERATITES OF THE CRETACEOUS
characteristic, having simply digitated or phylliform, often entire or bifid
saddles and narrow, often club-shaped, lobes digitated at their tops.
The first lateral saddles are usually bifid, but in some forms they
become trifid. In these cases the additional saddles are added on the
ventral side through the division of the outer arm of the first lateral
saddle. The group as here defined is confined to the Lower Senonian in
Europe, and the South American representatives are probably of about the
same age.
TISSOTIA Douvillé.
The definitions heretofore given of this genus have been based upon
the sutures which, according to the views here advanced, can not be accepted
when not correlatable with external characters. The type of this genus,
T. tissoti, so far as can be seen from the side view given by Bayle and the
front view by Douvillé, is unique in having a considerably inflated form
like some species of Subtissotia, but with keel and ventral channels bordered
by continuous ridges, and in the extreme gerontic substage a truncated
venter without either keel or channels. This certainly justifies the opinion
of Grossouvre that this species is closely related to Pseudotissotia galliennei.
According to the views here advocated, this genus is a direct derivative of
galliennei of the Turonian, as has been previously suggested by Peron.
Tissoria TIssoTi (Bayle).
Buchiceras tissoti Bayle, 1878, Expl. de la Carte géol. France, Voi. IV, pl. 40, fre. 1.
Tissotia tissoti Douvillé, 1891, Bull. Soe. géol. France, 3d ser., Vol. XIX, p. ae fe ole
Tissotia tissoti? Peron, 1897, Mém. Soe. géol. France, Paléontologie, Vol. VII, No. 17,
pl. 12, fig. 3.
The type of Bayle’s species, which is also the type of his genus
Tissotia, has been figured by him in side view and by Douvillé in front,
from the same type in the Eeole des Mines, Paris. Douvillé also describes
the specimen. It is therefore plain that it is a stout form without any very
marked nodes and is flat on the venter in its gerontic stage, having lost its
keel on the last part of the outer yolution according to Bayle’s figure,
which is natural size, and also Douville’s figure. This shell also, according
to Douville’s figure, preserves an unusually depressed venter having keel
and shallow chamnels on either side bordered by. faint ridges or carinze
throughout the adult stage. The loss of the keel is correlated with loss of
the gibbosity of the sides, these becoming flatter aud more convergent
outwardly.
TISSOTILD-®. 43
SUBTISSOTIA n. gen. Hyatt.
This group includes a number of the species heretofore associated with
Tissotia tissoti on account of the sutures. ‘These are unquestionably similar
in the simplicity of their outlines, but, as has been argued above, this fact
can not be considered as determinative in such peculiar retrogressive
groups, unless correlatable with other characteristics and especially with the
changes in the development both of the young and the gerontic stage.
The younger stages, so far as known, beginning with the neanic stage,
have, as a rule, very globose forms with continuous keels, the sides are
costated and terminate outwardly, with tubercles that form raised but
discontinuous ridges on either side of the keel. The venter is much
broader than the area included within these lines of nodes, except in the
gerontic stage, when it narrows down to the same limits as are common in
Metatissotia. The keel disappears in the gerontic stage and the lateral
coste and the nodes also in some species, according to Peron’s figures,
leaving the venter more or less rounded.
Type is Subtissotia inflata (Peron).
SUBTISSOTIA INFLATA (Peron).
Tissotia tissoti var. inflata Peron, 1897, Mém. Soc. géol. France, Paléontologie,
Woli valle sNow, 1, pl: 12s fio: 6:
The figures of this form, given by Peron, show an excessively stout
shell, increasing rapidly in transverse diameters by growth, with an
obtusely subacute venter, prominent keel, and slight channels on either
side, bordered by ridges. Peron’s figure at diameter of 68.5 mm. is 51 mm.,
while the figure of intermedia, which is 92 mm. in diameter, is 53 mm., only
3 mm. wider than the much smaller and younger specimen of inflata. Such
differences of proportion do not occur in the same species of Ammonites.
Locality: North Africa.
Age: Base of Senonian.
SUBTISSOTIA INTERMEDIA (Peron).
Tissotia tissoti var. intermedia Peron, 1897, Mém. Soc. -géol. France, Paléontologie,
Vol. VII, No. 17, pl. 12, figs. 4, 5.
Tissotia tissoti vay. levigata Peron, ibid., pl. 13, figs. 1, 2.
This form differs from inflata in having much less gibbous volutions at
the same age and a more acute venter at all stages.
44 PSEUDOCERATITES OF THE CRETACEOUS.
Locality: Northern Africa.
Age: Lower Senonian.
SUBTISSOTIA PERONI n. sp. Hyatt.
Buchiceras ewaldi Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 1, 2 (no other).
Tissotia ewaldi Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No.
Lf job WBE
This is based on a specimen from Tunis, of a diameter of 107 mm. It
is figured by Peron as having an entire keel throughout, although the
rounded tubercles on either side of the ventro-lateral angles have almost
disappeared at a stage when in his ewald? var. africana they would have
become elongated and very coarse and the keel have been resolved into
elongated tubercles. The venter is also entirely distinct in this species, in
its sharper outline and more prominent keel. These features are also
associated with peculiar sutures. The sutures of T%ssotia africana have a
lone, well-defined ventral lobe, the sides of the first laterals being abrupt,
5
io}
whereas in this fossil there is a very short, ill-defined ventral lobe, with the
sides of first lateral saddles denticulated and sloping. The first lateral
saddles are deeply divided in 7. africana, while in this the division is not so
well marked. The resemblances in form and sutures between this and
T. levigata show that they are closely related.
Locality: North Africa. :
Age: Base of Senonian.
SUBTISSOTIA AFRICANA (Peron).
Tissotia ewaldi vax. africana Peron, 1897, Mém., Soc. géol. France, Paléontologie,
Vole Vill Non iie plese toss 6:
At a diameter of 54 mm. the young figured by Peron is a very gibbous
form, in which the broadest diameter of the last volution measures about
39 mm. The keel is continuous and prominent even on this cast, and there
is a line of prominent tubercles on either side along the ventro-lateral
angles. In the aged specimen, figured at diameter of 108 mm., these have
become elongated, and the sides being less gibbous the venter is flatter, and
on this volution the keel begins to disappear, becoming resolved into
elongated nodes. There are no cost figured on these casts. Peron con-
siders this identical with Tissotia robini, as figured by Grossouvre, but robint
TISSOTILD 2. 45
is a costated compressed species with a continuous keel, even in extreme
age, atter the disappearance of the lines of tubercles, according to Grossouvre’s
figure. His ewaldi is similarly figured as a compressed shell, but not in
extreme of age apparently. This species is evidently distinct from 7. ewaldi
figured by Peron in his Mollusques Crétacés de la Tunisie, which attains a
large size, and at an advanced age still has an entire keel and rounded
tubercles. The resemblance of the youngof this species to the more mature
stages of Subtissotia inflata and intermedia is apparent, if Grossouvre is
correct in his assignment of the smaller casts figured to this species.
Locality: North Africa.
Age: Lower Senonian.
METATISSOTIA n. gen. Hyatt.
b= pe
Following out the system adopted in these pages, it becomes obvious
that species having the peculiar development of Metatissotia fourneli and
robini can not be associated with either 7issotia or Subtissotia. The entire
ontogeny, including the gerontic stage, of these highly compressed forms
is distinct from Tissotia and Subtissotia on the one side and from the more
accelerated development of Paratissotia on the other.
The typical ontogeny begins with a stage having a compressed smooth
form and a continuous keel. In the next stage there is a more or less trun-
cated venter having also a continuous keel, but with nodes at the termination
of cost that appear on the sides, and nodes also on the umbilical shoulders.
In the gerontic stage, the costa, keel, and channels finally disppear, leaving
the sides smooth or ornamented only with large nodes, and the venter more
or less angular.
MeETATISSOTIA FOURNELI (Bayle).
Buchiceras fourneli Bayle, 1878, Expl. de la Carte géol. France, Vol. IV, pl. 40,
fig. 3 (not fig. 4).
Tissotia fournel’ Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 10-14.
Tissotia fourneli Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No.
Lig ol: LO:
The development has been determined by Peron in his Ammonites de
lAlgérie, cited above. In the figures of his youngest specimen, which
measures about 30 mm. in diameter, there are large dichotomous coste
with alternating short single costze. In the oldest part of this specimen and in
46 PSEUDOCERATITES OF THE CRETACEOUS.
the stage represented by the next figure, the forks of the dichotomous costz
are becoming obsolete and being resolved into short cost, so that there are
two short nodose coste between the larger ones. This is obviously, how-
ever, very irregular, since in the figured specimen, which has a diameter of
85 mm., there is still one dichotomous costation. It is obvious, too, that the
costee, being very heavy, become fold-like with age. The longer cost
have nodes on the outer ends along the ventro-lateral angles, and “nodes
along the umbilical shoulders, which persist throughout the ephebic stage
and are present as very broad, low folds in the gerontic stage. According
to Peron’s description and figures, the short costee disappear and are appar-
ent only as simple nodes in large specimens.
This is a compressed form of this genus having an entire keel at an
early stage, and a close ally of the European species M. nodosa. Peron
has clearly shown that Bayle confounded two species under this name, but
I doubt whether Bayle’s Tissotia fourneli, figs. 4-5 of pl. 40, is identical
with ewaldi.
Locality: North Africa.
Age: Base of Senonian.
MeratissoTi1aA ROBINI (Thiolliére).
Ammonites robini Thiollicre, 1848, Ann. Soc. @Agriculture de Lyon, Vol. XI,
’
jolu al.
Buchiceras ewaldi Fallot, 1885, Ann. sci. géol., Vol. XVII, pl. 3, figs. 1, 2.7
>
Ammonites cfr. ewaldi Redtenbacher, 1873, Abhandl. K.-k. geol. Reichsanstalt,
Vol. V, pl. 22, figs. 5 a-i.
Tissotia robind Grossouvre, 1893, Ammonites Craie supérieure, pl. 4, fig. 1 (not
fio. 2 b). .
Tissotia ewaldi (pars) Grossouvre, ibid., pl. 9, fig. 5.
This shell has a compressed form, and the adult figured by Grossouvre
at a diameter of about 50 mm. has a truneated venter with prominent elon-
gated tubercles on the ventro-lateral angles and a prominent continuous
keel. At the end of this volution, or say at a diameter of 55 mm., accord-
ing to Grossouvre’s figures, these tubercles begin to disappear, and at a
diameter of 80 mm. they are absent, and the venter has consequently lost
its truncated aspect and become subacute. This agrees also with Redten-
bacher’s figure of a specimen which is 83 mm. in diameter, and in which
TISSOTIID®. 47
the old-age characteristics are similar. Grossouvre’s fig. 2, also named
robini, is apparently a distinct species. It has the subacute venter of the
oldest gerontie substage of true robini when only 59 mm. in diameter, and
this begins when the shell was about 40 mm. in diameter or earlier, accord-
ing to this figure. This whole volution is also covered by dichotomous costee
having only very faint tubercles. This might be a dwarf of this species,
but is apparently not a young specimen. Redtenbacher’s figures (except
perhaps 5, f and h) all appear to belong to this species, and fig. 5f may
have been a worn specimen or a dwarf. At any rate, the latter has a
suture with the first lateral saddles looking remarkably like an immature
stage of those characteristic of robini. Grossouvre thinks this is the true
ewaldi of Buch, but on the contrary it seems to me more likely that part of
his ewaldi as given above belongs to rebini. The peculiar ventral trend of
the outer divisions of the first lateral saddles occurs apparently only in this
species. Redtenbacher’s figures are of value in that they give information
with regard to the young, showing that at a diameter of about 18 mm. the
keel is prominent and continuous, as it is in later stages, the cost are well
developed and uichotomous and have two rows of tubercles, one on each
umbilical shoulder and a row on either side of the keel. It is also to be
noted that the venter of this young specimen is more acute and the whole
form more compressed than in the more mature stages.
Locality: France and Austria.
Age: Senonian.
METATISSOTIA NODOSA 1. sp. Hyatt.
Tissotia haplophylla (pars) Grossouvre, 1893, Ammonites Craie supérieure, pl. 4,
figs. 3, 4 (not fig. 5).
The two specimens figured by Grossouvre have large nodes on the
umbilical shoulders like those of haplophylla, but the costz are well
developed at an age when these are absent in true haplophylla, as shown in
Redtenbacher’s figure. The keel at the same stage is entire, whereas in
haplophylla there is a row of tubercles.
Locality: France.
Age: Coniacian.
48 PSEUDOCERATITES OF THE CRETACEOUS.
METATISSOTIA HAPLOPHYLLA (Redtenbacher).
Ammonites haplophylla Redtenbacher, 1873, Abhandl. K.-k. geol. Reichsanstalt, Vol.
V, pl. 23.
Tissotia haplophylla (pars) Grossouvre, 1893, Ammonites Craie supérieure, pl. 4,
fig. 5 (not figs. 3,4).
This form is compressed, but has heavy fold-like costze and very stout
nodes on the umbilical shoulder and ventro-lateral angles, the venter being
similar to that of MW. fowrneli, but with a line of nodes instead of a con-
tinuous keel. The French fossil quoted above may possibly be the same,
but it has quite a distinct aspect, and the supposition of Grossouvre that
the sutures will prove to be similar when those of the Austrian specimen are
better known, is not sustained by the collateral evidence. Grossouvre’s
figs. 3 and 4 of the supposed neanic stage of bis haplophylla are certainly
quite distinct, having an entire keel and aspect allied closely to Metatissotia
fourneli and robini and here treated as distinct under the name of Meta.
nodosa.
Locality: Austria.
Age: Senonian.
METATISsoTIA EWALDI (von Buch).
Ammonites ewaldi von Buch, Abhandl. K. Akad. Wiss. zu Berlin, 1848, pl. 6, figs. 6, 7.
Tissotia ewaldi (pars) Grossouvre, 1893, Ammonites Craie supérieure, pl. 4, fig. 6 (not
pl. 9, fig. 5).
This species is very similar to Meta. robini, but, so far as known by
the figures of Grossouvre and others, these two species appear to be distinct
in their sutures. Both species have the first lateral saddles deeply divided
and the outer arms of these are shorter than the inner ones, but the outlines
of these outer arms in this species are rounded, phylliform, undivided, and
straight or parallel with the keel. In robini these outer arms are inclined
toward the keel and the outlines are subdivided by marginal lobes in
mature specimens.
Locality: France.
Age: Senonian.
TISSOTILD.%. 49
MrTATISSOTIA AURESSENSIS (Peron).
Tissotia auressensis Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII,
No. 17, pl. 13, figs. 4, 5.
This is a cast of what is apparently an old shell. The form is not
unlike that of Paratissotia grossouvrei, with a similar large umbilicus, and it
might be considered as perhaps the gerontic stage of this species, but the
sutures are so distinct that this supposition is not tenable. These have
extraordinarily large and long phylliform saddles, and the first lateral
saddle has a conspicuously trifid base.
Locality: North Atriea.
Age: Senonian.
METATISSOTIA SLIZEWICZI (Fallot).
Buchiceras slizewiczi Fallot, 1885, Ann. sci. géol., Vol. XVII, p. 240, pl. 2, fig. 2.
pleei, tie., 2:
This species, if correctly given by Grossouvre, has a young form which
at a diameter of 41 mm. has a truncated venter, continuous keel, a line of
small tubercles along each ventro-lateral angle beginning on the last
volution at about this size, and also a line of nodes on the wmbilical
shoulders. The form at this stage is like that of Tissotia ef. fourneli Peron.
The sutures are also similar in having trifid first lateral saddles and other
saddles and’ lobes long and large. The three marginal saddles and lobes
are much more completely developed, longer, and the first lateral saddles
broader in consequence of this differentiation of the outlines. The nodes
on both lines are much larger in the large shell figured and the keel
persists. The umbilicus is also of good size, as in the species of Peron
referred to above. Peron considers all of these forms to have occurred
in the Senonian, and his evidence is very strong on this point.
Locality: France.
Age: Coniacian, base of Senonian.
MON XLIV—03——+
5O PSEUDOCERATITES OF THE CRETACEOUS.
PARATISSOTIA n. gen. Hyatt.
Highly compressed smooth forms like the type of this genus, P. regularis
and ficheuri, omit the characteristic nodose stages and more or less obtuse
or flattened keeled venters of Metatissotia or else pass through them at an
early stage, becoming later highly acute and smooth or at least without
prominent nodes in their mature stages. In the two species examined
they never have channeled venters at any stage. The discovery of a
hollow keel in the later stages of P. regularis would have caused me to
separate that species from the other species referred to this group had their
development been different and the structure of their keels also known.
PARATISSOTIA GROSSOUVREI (Peron).
Tissotia grossouvre’ Peron, 1897, Mém. Soe. géol. France, Paléontologie, Vol. VII,
No. 17, pl. 16, figs. 1, 2:
This is similar in aspect to P. ficheuri, but is less involute, the umbilicus
being much larger and the sutures distinct. The first lateral saddles have
denticulated outlines instead of the smooth, phylliform arms of P. ficheuri.
The young have not been examined, but the adult appears to belong to
this genus.
Locality: North Africa. :
Age: Lower Senonian.
ParatissotTia ? THOMASI (Peron).
Tissotia thomasi Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII,
No. 17, pl. 18, fig. 3 (not pl. 16, figs. 5, 6).
The type of this form is a compressed shell with very involute whorls
and the zone around the umbilicus depressed and flattened. The venter,
at least in advanced age, has a simple, not very prominent keel,
unaccompanied by tubercles of any kind and sides almost smooth.
The form is not sufficiently well known to be placed here without a
query after the generic name.
Locality: North Africa.
Age: Base of Senonian.
TISSOTIID-E. 5yI
PARATISSOTIA FICHEURI (( rrossouvre),
Tissotia ficheur? Grossouvre, 1893, Ammonites Craie supérieure, p. 35, fig. 17.
Tissotia ficheuri Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VIL,
No. 17, pl. 12, figs. 1, 2; pl. 18, fig. 2.
Buchiceras ewaldi (pars) Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 3-6.
Buchiceras fournel (pars) Bayle, 1878, Expl. de la Carte géol. France, Vol. IV, pl.
40, figs. 2 and 4 (not fig. 3).
This is a very much compressed shell, with no channels on either side
and no tubercles on the costs, which are simple and very slightly
developed. The keel is prominent and acute, and the umbilicus is very
small. The costee are shown by Peron in the side views of a young
specimen having a diameter of 55 mm. and in a very old shell with
diameter exceeding 115 mm. In both the costs are linear and straight,
with only the outer half developed. A description of this last specimen,
which is evidently very old, would have been of much interest, but it is
not given. The very broad, low denticulated saddle occupying the
extremity of the ventral lobe and the deeply divided denticulated first
lateral saddles of this species, of which the outer one is bifid and the inner
has a broad, phyllitorm base, are very peculiar, as are also the costee. The
very globose fossil figured on pl. 15, fig. 8, by Peron in his Mollusques
Crétacés de la Tunisie as part of his Buchiceras ewaldi 1s undoubtedly a
distinet species, but the information given is too limited to enable one to
refer it to any known species. The reference of part of B. fourneli Bayle
to this species is given on the authority of Grossouvre. Bayle’s figures
are handsome, but not very instructive.
Locality: North Africa.
Age: Base of Senonian.
PARATISSOTIA SERRATA (Hyatt).
Pl. II, figs. 7-11.
Buchiceras serratum (pars) Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII,
p- 370.
This is a fragmentary cast of more than one-half of an entire coil, without
living chamber. The diameter without the shell is 37 mm. The outer
volution measures 20 mm. at larger end, the umbilicus 4 mm., and opposite
2 PSEUDOCERATITES OF THE CRETACEOUS.
Or
side of outer volution from line of involution to venter is 17 mm. The
shell reduces the diameter of the umbilicus to 3 mm.
The cast of the outer volution is perfect only on one side. This is
planoconvex and covered with regularly arranged costz, of which there
are eight to half of a volution on the inner part of the whorl. The costee
broaden and flatten outwardly, becoming sigmoidal in curvature and then
bifureate, the branches bending well forward and rising into elongated
swellings on the cast. These are about 3 mm. from the outer edge of the
keel, and there are very slight obsolescent ridges beyond them, which,
however, do not cross the smooth bands on either side of the keel.
The venter on the first part of the outer volution, the third quarter, is
subacute, but on the last quarter it is beginning to be rounded, the keel
having disappeared. This shows that the shell was in the gerontic stage,
and the approximation of the last two sutures also indicates the same stage.
There is also the trace of a line, probably a line of involution, impressed
upon this part of the outer volution, showing that the living chamber must
have decreased very rapidly in the amount of involution, since it did not
cover quite half of the sides on the third quarter and part of the fourth
quarter of the now exposed volution. The length of the absent living
chamber could not be determined, but that it was much rounded and
depressed on the venter and in an extreme stage of gerontic degeneration
is highly probable. The sutures are more like those of Paratissotia fourneli,
as figured by Grossouvre in his Ammonites de la Craie supérieure. The
ventral lobe is, however, very short, broad, and opens widely, with two
small, short, entire arms. The siphonal saddle is broad, prominent, and
entire, with a hardly perceptible median marginal lobe or depression, which
seems inclined to disappear in the gerontic stage. The first lateral saddle
is large, as in other species of this group. On the third quarter of the
exposed volution it is plainly only one bifid saddle, but on the fourth
quarter the dividing marginal is deeper, and there appear to be two dis-
tinct saddles, as in P. djelfensis. The outer arm of the saddle shows a
hardly perceptible median marginal, as in P. fowrneli. There are five
other lateral saddles, all entire, and, like the first lateral, very short
and extremely broad like those of P. fichewri, as figured by Grossouvre.
The first lateral lobe is broad at the end and denticulated exactly as in
Tissotia tissoti and Metatissotia ewaldi as figured by Douvillé, but it is very
short and broad. The second laterals are smaller and also denticulated.
TISSOTIID.®. 53
The remaining lateral lobes are like those of the same species, but
very much narrower, and the second to the fifth hardly more than mere
indentations.
The dorsal sutures were seen only from above. The antisiphonal
lobe was obviously very narrow at the base, but its length could not be
determined. There are seven pairs of entire zygous dorsal lobes and
saddles, the latter much narrower than the external laterals. The first and
second lateral saddles are connected across the septum by broad ridges, so
that the septum observed was convex externally and internally along the
mesal plane, but concave along the center. The saddles on the dorsum
and the corresponding external sadd'es were connected only by very
slight ridges, and the intermediate surtace of the septum was convex.
obose, keelless form of the
Oo
t=}
The figures of sections show the broad
nepionie stages and perhaps of the earliest of the neanic stages. The
siphuncle is certainly very small and the keel is solid when it first appears,
as shown in figure. The disappearance of the siphuncle left me in doubt
with reference to its structure in later stages.
Locality: Cachiyacu, west side of Huallagua River, Peru.
Age: Upper Cretaceous, probably Senonian.
PARATISSOTIA REGULARIS n. sp. Hyatt.
Pl. IIL, figs. 1-6.
Buchiceras serratum Hyatt (pars), 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII,
p. 370.
This species has a broad volution with a rounded venter until the shell
reaches a diameter of 6 mm. Paleontogr., Vol. I, 1851, p. 324, pl. 41, figs. 21-24.
¢The other species mentioned and figured by Uhlig are not named. They are closer to the
involute character of P. heteropleurum, but one of these, Oxyn. cf. heteropleurwm, pl. 2, fig. 2, has three
principal saddles instead of two and is considerably less involute than that species.
COILOPOCERATID®. 91
COILOPOCERAS ¢ n. gen. Hyatt.
This genus includes species formerly associated with Sphenodiscus,
which, however, differ so that they are easily separated. The development
and form are closely similar; that is to say, the shell develops directly
from the rounded nepionic volutions into a helmet-shaped whorl in section
having subacute venter which hecomes more acute with age. In the three
forms described below in the neanic and adult stages, the volutions are
somewhat less compressed than in species of Sphenodiscus, but this is prob-
ably only a specific character.
The sutures differ in having broad first lateral saddles with a peculiar
large internal arm or marginal saddle, and the first and second laterals, when
the second are present, are narrow and very distinct from the first laterals
on the outer side and the first large auxiliary saddles on the inner side.
There are but two secondary lateral saddles, the first and second, derived
from the division of the primitive first laterals in C. colleti, the type of the
genus, but this form is in an early ephebie substage and the aspect of C.
novimexicanum at a somewhat older stage shows that there is an approxima-
tion to the trisellate condition. This trisellate or placenticeran aspect of
the principal or first outer saddles, derived from the division of the primi-
tive first lateral saddles, is still more marked in C. springeri. The hollow
keel is remarkably distinct. When the shell is removed, the siphunele is
covered only with a very thin layer of the fossilizing sediment, and_ this
organ is apt to be exposed on the casts and is often absent in more or less
worn specimens, leaving the venter deeply channeled. This last accident
is of rare occurrence among forms with solid keels. The siphuncle is also
larger and thicker walled than in Sphenodiscus.
CoILOPOcERAS COLLETI n. sp. Hyatt.
Pl. X, figs: 5-21 Ply ahead:
This species is easily distinguished by comparison with its nearest
affine, Coilopoceras novimexicanum. It has stouter volutions, a more open
umbilicus, the venter is blunter, and in the young, at any rate, it has larger,
stouter fold-like costae, one lone one reaching to the umbilical shoulder
.o o y
« KotAwr7os, hollow.
92 PSEUDOCERATITES OF THE CRETACEOUS.
and an alternating shorter one. This last series disappears in the last part
of the outer volution of the specimen described, leaving a series of single
cost. ‘These may perhaps be obsolete or obsolescent in older specimens.
There is a decided aspect of bifurcation in the earliest stage observed when
from line of involution to venter the cast of the volution is 15 to 20 mm.,
but there are no tubercles. The whole diameter of this cast is 67 mm.
The outer volution at largest end from line of involution to venter is 37 mm.;
without the shell the umbilicus is 7 mm. on one side and 8 mm. on the
other side; with the shell it would be 5 mm. on one side and 6 mm. on the
other. The greatest transverse diameter is about one-third of lateral zone
distant from umbilicus and is for thickest part 18 mm., and opposite, cor-
responding to ventro-dorsal diameter above given, it is 11 mm., both
measurements being between the costae. The costa are more prominent on
the middle and inner parts of the sides than on the outer, and broaden
out toward the venter, disappearing near the solid edge somewhat abruptly
on the younger parts and more gradually along the older part of this
volution.
The first lateral saddles are broad and short trifid on the right side,
with a small outer marginal saddle and quadrifid on the side figured (PI.
X, fig. 7), with an inner accessory large marginal saddle dependent on the
first laterals. The second laterals are single, short, but slender saddles,
with phylliform bases, which are only slightly indented at the age observed,
The third laterals are only about a third longer than these, and, although
overlapping, are easily separated. The outlines are irregular and deeply
indented by two marginal lobes and other accessory lobes. The fourth and
fifth laterals are phylliform, with the bases indented by a number of
marginal lobes, apparently entire and small. The sixth and seventh laterals
are faintly trifid. The almost entire aspect of these saddles is due to slight
abrasion. On the youngest part of this volution (PI. X, fig. 9) all of the
saddles are entire except first to third, the cast here being 16.5 mm. in
breadth from line of involution to venter; the outlines are perfect.
The ventral saddles are more like those of Sphenodiscus than in
novimexicanum, and have rounded marginal saddles at the inner angles.
The first lateral lobes are of about the same length as the arms of the
ventral lobe, both of them trifid and with accessory marginal lobes orad of
these. The second laterals are the deepest lobes, and represent the primitive
COILOPOCERATID.®. 93
lateral. They are bifid and about twice as long as the third, the arms and
sides being cut up by marginals. The remaining lobes are narrow as
compared with the saddles, and irregularly denticulated. 1 could not tell
whether they were of the trifid or bifid type, or both mixed. There were
eight lobes, the line of involution being oceupied by a saddle.
The venter is capped by a hollow keel, as in novimexicanum, and in this
species there is the plug, the dark layer, and an inner-shell layer, upon
which the ventral saddles and lobes abut.
The sutures are more like those of novimexricanum than any other
species, and I at first considered this to be the young of that species; but the
difference in these and in the external characters at the same age are far too
marked.
The saddles and lobes are all shorter than in novimexicanum and
overlap a trifle only from the fourth lateral to the umbilicus. They are
also much less complicated in outline or less cut into by marginal lobes, and
less distinctly phylliform.
The young in section, so far as seen, showed the same general
development as in Sphenodiscus, but the division of the primitive first laterals
took place early in the neanic stage.
The figures (PI. X, figs. 10-21) give the stages as far as these could
be studied. The protoconch is stout and slightly scaphitoid or irregular in
shape, like many other Cretaceous forms The second suture had a minute
siphonal saddle that was distinctly seen by a side light. Fig. 11 shows
the deepening of the antisiphonal and the beginning of the two first dorsal
saddles on the first quarter of the second volution. Fig. lla shows the
lengthening of the antisiphonal, the incoming of two saddles and the
beginning of a third on the dorsum, the incipient stages of division of
the primitive second lateral into four saddles of the auxiliary system and
the arising of the second lateral saddle on the inner side of the primitive
first lateral saddle. Fig. 12 shows the progressive lengthening of the
antisiphonal, the presence of a third pair of fully developed saddles on the
dorsum, the division of the primitive second lateral into four, the definite
separation of the second lateral saddle, and the incipient stage of the great
inner branch of the first lateral saddle; also the first appearance of the
smaller marginals on the outer side of the base of the same
94 PSEUDOCERATITES OF THE CRETACEOUS.
.
This specimen, therefore, affords clear ideas of the mode of development
of the full-grown sutures in this form and also in the group to which it
belongs.
Locality: Near Carthage, N. Mex.
Age: Colorado eroup, Upper Cretaceous.
g |
COILOPOCERAS NOVIMEXICANUM nh. sp. Hyatt.
Pl. X, figs. 1-4.
This species appears to be more like Sphenodiscus lenticularis Meek
than any other at first sight, but the sutures and other characters are so
dissimilar that this impression is easily corrected.
The cast in hand is 93 mm. in diameter and, allowing for siphuncle on
one side and crests on both sides, it would be, when perfect, about 96 mm.
The transverse diameter of the outer volution is 56 mm., the umbilicus is
about 1.5 mm., and the outer volution below on same line is 34 mm. without
siphuncle and crest, which would make it with both about 35.5 mm. The
transverse diameter, about the middle of the lateral zone, is 23 mm. for the
largest, oldest part of the volution and 15 mm. for the smaller, younger
part opposite this. The latter had the shell on both sides, and deducting
this it would be 14 mm.
While the form and aspect were the same as in most other species of
this genus, it has very faint fold-like costa on the outer part of the last half
of the outer volution and more decided and more fold-like costations upon
the younger portion and on first quarter of the exposed volution; these last
reach to the umbilical shoulder.
The venter is subacute, with blunted, narrow crest, and on either side
of this lateral zones are slightly concave on the entire outer volution. The
shell vaulted over a clear space above the siphuncle, the hollow keel, and
this was filled by clear, crystalline limestone different from the matrix,
and there was a black layer over the siphuncle. Farther out a part of the
black layer was found to consist of black dendritic oxide of iron. The
sutures are equally peculiar. Upon closer examination it is seen that the
resemblances to Placenticeras are due to the small size of marginal saddles,
the solidity of the fourth lateral saddles and the greater complication of
the smaller saddles than in Sphenodiscus. There are, however, but two
COILOPOCERATID-E. 95
secondary lateral saddles, although the deep division and length of the
inner branch of the first laterals make apparently three saddles. The outer
branch of the first lateral saddles is narrow, long, much cut up by marginal
lobes, bifid, and has phylliform elongated marginal saddles. They slightly
overlap the branches of the ventral lobe, except in the two sutures figured.
A large marginal springs from their orad parts inward, forming a narrow
saddle with phylliform single base, undivided on the younger parts of the
volution and beginning to have a small lobe on outer side in older parts
of same. These are much longer than in colleti, are attenuated and cut
into by marginal lobes, and would usually be counted as the second laterals.
They do not reach to the next sutures and are separated by bare spaces
from the outlines of the second lateral lobes. The pointed aspect of the
marginals is noted in Pl. X, fig. 4, but the slightest abrasion would obliterate
such marks and make all the marginals appear to be rounded, as they did
to me at first.
The second laterals are nearly all on a level with these inner branches
of the first and have solid elongated bases, which are cut inte only by
small pointed marginal lobes and consequently subphylliform, but apicad of
these there are on each saddle two projecting phylliform branches. The
third laterals, first auxiliaries, are fully one-third longer than the second
and broad and solid throughout; the apical openings are not contracted,
their marginal saddles and lobes bemg small and short. The extraordinary
length of these saddles causes them to overlap the inner outlines of the
third lateral lobe so much that one is apt, unless aware of this, to confuse
Hl
two sutures and consider this saddle short and broad. ‘The remainin
eo
fo)
saddles decrease in length to the umbilicus. The fourth are like the
third in aspect; the fifth are slender, phylliform, and bifid; the sixth are
slender, single, and phylliform; the seventh less elongated, less slender, but
phyllitorm, and near the umbilical shoulders. On the umbilical zone there
are two rows of saddles visible on the last part of the outer volution, having
still the rounded phylliform bases of the Sphenodiscus type. The siphonal
saddles are quite distinct, larger and more prominent and unlike those of
any other allied species.
The ventral lobe is similar to that of Sphenodiscus lenticularis, but has
spreading trifid arms. The first and second lateral lobes are narrow. The
first is decidedly bifid, the second is but a shade longer than the first, and
96 PSEUDOCERATITES OF THE CRETACEOUS.
the sutures have to be perfect to see this clearly. The third is about
one-half the length of the second, and from this one the decrease in length
is gradual to the lines of involution. The third, fourth, and fifth lateral
lobes are broader in proportion and correlate with the forms of the
accompanying saddles. There are eight lobes and nine saddles on the
oldest parts of this volution, the seventh lobe being on the umbilical
shoulder.
The septa are concave along the median plane, bemg convex only at
the ventral and antisiphonal lobes. The large third saddles, the first of
the auxiliary series, correspond to the first pair of dorsals and are connected
with them so that the number of saddles on the dorsum is the same as the
number of lateral saddles, or six, exclusive of the saddle on the line of
involution. The details of their curves could not be seen.
Locality: Near Carthage, N. Mex.
Age: Colorado group, Upper Cretaceous.
CoILOPOCERAS SPRINGERT n. sp. Hyatt.
Pl. XII, figs. 1-3.
This superb specimen, presented to the Museum of Comparative
Zoology by Frank Springer, of Las Vegas, the well-known student of
crinoids, appears to have characters so distinct that they can not be
accounted for by the extreme size and age of this specimen. it’ is 400
mm. in diameter. The last part of outer volution from lines of involution
to venter, which is slightly truncated by abrasion, is 225 mm., and half of
a volution younger it is 196 mm. This, judging from thickness of the shell
on younger part (5 mm.) and siphunele at this part 7 mm. in diameter, has
lost 12 to 15 mm., and to this must be added shell in the umbilicus, which
was 5mm. At the last part of the second quarter of this volution, where
sutures were studied, the volution was 195 mm. in breadth; the allowance
of 5 mm. for shell on venter and of 3 mm. for shell in umbilicus makes the
volution when complete 203 mm. The actual measure of same diameter
near beginning of first quarter, which was entirely covered by shell, was
149 mm. The inner layer of the shell was not present in umbilicus and
probably added 2 mm. to this measurement.
There is only a small part of the living chamber left on this large
COILOPOCERATID®. 97
specimen, and its original length is not clearly indicated by any marks on
the exposed volution. The shell is only partly preserved, but it is sufficient
to enable one to state that there are no tubercles nor distinct coste on
either shell or cast.
The venter is subacute and appeared at first to be solid, but close
examination showed a small core of light-colored filling and a fine darker
layer between this and the large siphuncle. The small size of the core was
due to the great age of the specimen, and probably at a still older age the
keel was entirely solid. The last part of exposed volution is obviously in
the extreme gerontic stage, since the line of involution has retreated consid-
erably from the previous normal line of involution, beginning its departure
on the first quarter and thus greatly enlarging the diameter of the umbilical
opening. The diameter of widest part is 40 mm. without the shell; with
the shell it was 8 mm. less, whereas that of the opening in next’ inner
volution was only 10 mm. with the shell on. The oldest sutures were
closer together, and, like the decrease of involution, indicated that the
specimen was outgrown; but these did not show the extreme degeneration
sometimes found at the end of the paragerontic substage. The sutures on
last half of the exposed volution were not in good condition and those
described below were about the middle of the volution, or in what I took to
be the metagerontic substage. The sutures were at this time separated by
a good interval, the first overlapping being between the fourth saddles and
the inner side of the third lobes. The next overlapping was between the
seventh saddles and continued thence to umbilicus. The first lateral saddle
on left side is very broad and of the trifid type, and the marginal saddles
elongated and phylliform in outline. It has an inner branch which is
phylliform, and although it might be reckoned as the second lateral, is only
a marginal, as in other forms of this genus. The corresponding marginal
in novimexicanum is smaller, and is not at all likely to be mistaken for a
second lateral saddle.
The second is somewhat larger and less phylliform than this branch of
the first lateral, but has similar characters. The third is still longer and
larger and has lost more of its phylliform aspect through the development
of the long marginal lobes. he fourth saddle is very long and large,
rising above the level of the first laterals, and is deeply cut and
unsymmetrically trifid, each branch being subdivided except the central
‘
MON XLIV—(03
98 PSEUDOCERATITES OF THE CRETACEOUS.
one. The remaining saddles are very short, broad, and more or less
phylliform. he fifth is entire with exception of minute marginals; the
sixth is trifid without secondary marginals; the seventh and eighth are
unsymmetrically bifid; the ninth and tenth are entire and phylliform. The
eleventh saddle passes across the lines of involution and forms the seventh
saddle of the dorsum. The corresponding saddles on the right side are
quite distinct in detail, but of the same number and similar in general
aspect. However, the fifth and sixth laterals are unsymmetrically trifid
with secondary marginals, showing that they were on the road to the
quadrifid type,“ and the seventh is bifid. The remaining saddles are shown
on the same side at an older stage. The eighth, ninth, and tenth were
phylliform and entire; the eleventh was entire, and situated on the line of
involution. The lobes on the left side were as follows: The first laterals
were merely marginals on the first lateral saddles, the first corresponding to
the first saddle, as reckoned above, the second and third progressively
deeper. The third, although it was apparently trifid in type, was
subdivided by a very long, slender, and peculiar marginal saddle coming
from opening of fifth lateral saddles. The fourth, fifth, sixth, and seventh
laterals were broad at the tops and had pomted small marginals as in some
other more primitive species. The eighth, ninth, and tenth had more
unequal serrations and were narrow at the tops.
The adult sutures were exposed on an inner volution and exhibited, as
I anticipated, more overlapping than in the gerontic stage, owing to the
greater length and. development of the second and third lateral saddles.
This is an instructive case because, as a rule, the overlapping is greater in
the gerontic stage than in the ephebic. In the extreme gerontic stage,
when the decrease in length of the saddles and lobes is greatest, the
approximation of sutures causes overlapping, notwithstanding this decrease.
But in a prolonged gerontic stage the relative decrease in length of lobes
and saddles may sometimes, as in this case, where septa are not much closer,
cause sutures to appear wider apart than in the ephebic stage.
The adult sutures had very much the same outlines as in the gerontic
stage described anove, but there was a slight overlapping along the entire
suture.
“This shows a variation between the two sides that is interesting, and it must also be noted that
there is a slight overlapping on this side, owing to the greater length of the fifth and sixth saddles.
COLLOPOCERATID.. 99
There were three principal lateral loves and the third was the remnant
of the primitive lateral lobe.
The dorsal sutures were seen in the gerontic stage and a partly restored
outline of the antisiphonal is given in Pl. XII, fig. 3. The right outline and
the end of the lobe are restored. The extreme bifid end of this lobe was,
however, seen from below. The first dorsal saddle was clearly seen but
was apparently abraded like the antisiphonal, and the remaining saddles
were seen, but not in such connection as to make a drawing desirable.
They correspond in outlines to the opposite lobes and saddles of the aux-
iliary series, being entire and phylliform near the lines of involution and
trifid near the first pair of dorsals. The lobes also are digitated like their
Opposite companions of the auxiliary series. There are six pairs of saddles,
with a seventh continuous with the eleventh outer saddles, and six pairs of
lobes, the antisiphonal making the thirteenth lobe on the dorsum.
Locality: Rit du Plain, Colfax County, N. Mex.
Age; Colorado group, Upper Cretaceous.
COILOPOCERAS REQUIENIANUM (d’Orbigny).
Ammonites requienianus VOrbigny, 1840, Terr. Crétacé, pl. 93.
The suture given by d’Orbigny has a large first lateral, but it is narrow,
long, and bifid, with a third arm on the external side. The two next saddles
have the relations common in this genus, the second being hardly distin-
euishable as an independent saddle, narrow, phylliform and bifid, while the
third, which is large enough to be ranked as an independent saddle, is
narrow, phylliform, and trifid. The auxiliary series has the broad complex
saddle to begin with, reckoned in these descriptions as the fourth lateral,
and the remaining saddles have the usual phylliform bases, all that are
drawn, four in number, being bifid.
The outlines approximate more nearly to those of the phylloceran group
like Aconeceras nisum. The siphonal saddle, if correctly drawn, is interme
diate in aspect between the broad ventrals of other species of this genus
and those of such forms as Platylenticeras heteropleurum, with narrower
siphonals.
Locality: Uchaux, France.
Age: Turonian.
100 PSEUDOCERATITES OF THE CRETACEOUS.
CorLopocERASs? GROSSOUVREI n. sp. Hyatt.
Pl. XI, fig. 7.
Sphenodiscus requient Grossouvre, 1893, Ammonites Craie supérieure, p. 141, fig. 59.
The suture and description given by Grossouvre of his French species
and the one figured by d’Orbigny as Ammonites requienianus, although
quoted as identical by him, are very different. ‘There are distinctly three
principal lateral saddles in Grossouvre’s figure, but the first is large, long,
and trifid instead of being narrow, long, and bifid; the second is really an
enlarged branch of the first saddle and still entire, while the third is bifid and
much larger than in true requieni, according to d’Orbigny’s figure. This
species may be one of the hollow-keeled group, a suggestion that is further
supported by the aspect of the auxiliary saddles and lobes. In order to call
attention to these points I have placed a question after the generic name.
Locality: Near Tours, France.
Age: Turonian.
ACONECERAS*? n. gen. Hyatt.
The single species here referred to this genus has sutures more like
those of Cretaceous forms of Phylloceratida than any others of this group.
These are combined with a highly involute compressed shell having an
ax-like acute venter like a species of Hulophoceras. The ventral saddle, as
figured by d’Orbigny, is broad and similar to that of Codlopoceras; the first
lateral and the other saddles are deeply divided and broader than in the
Phylloceratida and certainly show approximation to those of the Coilopo-
ceratidee. I have therefore referred the form to this family, and it appears
to strengthen the opinion that the Coilopoceratidze were derived from the
Phylloceratidee.
ACONECERAS NisuM (d’Orbigny).
Pl. XII, figs. 46.
Ammonites nisus VOrbigny, 1840, Terr. Crétacé, pl. 55.
This figure is copied from d’Orbigny because it gives what appears to
be an important link in the evidence that the group to which it is referred
is correctly referred to the Phylloceratida.”
Age: Neocomian.
a Axovy, a whetstone.
» The two pages of manuscript bearing these notes on Aconeceras were out of place, lying at the
top of one of the two bundles of manuscript, and just before the generic name is the penciled note,
SYSTEMATIC DESCRIPTIONS 101
COSMOCEH RR ADD:
VASCOCERAS Choffat.¢
This genus, thanks to the researches of Choffat,’ can now perhaps be
assigned to its proper group. In my chapter on Cephalopods in Zittel’s
Text-book I placed it with a question mark in the Acanthoceratidee. It is
apparently a group of very broad coronate shells having in the young
adolescent stage of some primitive forms (ex. V. subconciliatum, Choffat)
three rows of tubercles, which are often large nodes on casts. The section
is essentially helmet shaped at this age, the umbilical zones very abrupt,
and the diameter through the umbilical shoulders much greater than that
through the ventro-lateral angles. The absence of a keel and the rounded
ventral zone, interrupted by costs in some forms, are characteristics that,
together with the lateral nodes and section, are similar to the young stages
of Coronites and the discoidal forms of Hoplites that have similar coronate
young with a line of large nodes. The sutures have remarkably broad first
lateral saddles and ventral lobes that are similar to those of some species of
Heinzia and Metoicoceras. These and the other characters indicate that this
genus may have had relations to typical Pulchelliidee similar to those that
‘Belongs with the Desmoceras group.’ It seems probable, therefore, that Professor Hyatt had
changed his opinion concerning the relationship of the genus, but as he had arranged figures of it on
the plate in connection with figures of Coilopoceras, it is thought best to print the manuscript as
written. The statement that ‘‘the group * * * is correctly referred to the Phylloceratida’’ is
evidently in conflict with the general note on the Mammitida, which is made to include the Coilopo-
ceratidze and many other families. I have not been able to determine which of these views was last
held by Professor Hyatt, but the arrangement of the manuscript gave the impression that Aconeceras
was removed from Coilopoceratidee as the result of later studies and that much of the evidence for the
relationship of the family with Phylloceratida was thus removed. —T. W. S.
“Jn the manuscript a sheet is inserted just before Vascoceras with the heading ‘‘Cosmoceratida,’’
followed by ‘‘In family description notice resembiance of form to Aspidoc. of Jura as more remote
than to Cheloniceras of the Cretacic.”” Another memorandum bears pencil-sketch copies of
d@Orbigny’s figures of Ammonites royerianus (Pal. Fr. Terr. Crét., I, pl. 112, figs. 3, 4) labeled
Cheloniceras royerianus, indicating that he had probably selected this species as the type of a new
genus. It is inferred from this that he had referred Vascoceras to the Cosmoceratida, and that he
intended to name and describe a new family to include this genus and possibly Tolypeceras. But did
he also intend to put Coilopoceratidee, Pulchelliide, and all the families that follow in the Cosmoce-
ratida? I can see no evidence of it, except in the arrangement of the manuscript and the absence from
it of other super-family names. Certainly no justification for it can be found in the definition given
by Professor Hyatt in Zittel’s Text-book. In the plates Vascoceras follows Coilopoceratidee, and I
have changed the arrangement of the manuscript sheets as found so that the descriptions follow in the
same order, believing that this is a more natural order and that it represents Professor Hyatt’s latest
views, as the last work he did was the mounting of these drawings in plates.—T. W. S.
»Faune Crét. du Portugal.
102 PSEUDOCERATITES OF THE CRETACEOUS.
.
highly coronate forms like Erymnoceras in the Inferior Oolite have to true
Stepheoceras, but until the young are known there can be no certainty in
such conelusions.
The similarity of this genus to Olcostephanus is very close indeed. The
costz on the venter of that genus are, however, not so fold-like, and the nodes
on the umbilical shoulders are correspondingly smaller and more numerous.
The sutures in Olcostephanus are much more complex in outline, and there
are fewer saddles and lobes.
The coronate form of the volutions and deep open umbilici retained in
some untuberculated shells have a certain remote resemblance to some
forms of Pachydiscus, but, so far as | know, none of these, nor any species
of Cretaceous Ammonitinze, have volutions so excessively depressed and so
similar to the Stepheoceratidee of the Jura and some Goniatitine of the
Carboniterous.
The living chamber is full three-fourths of a volution in length. Lat-
eral zones do not exist, the umbilical zones being abrupt and the umbilical
shoulders on the lateral edges of the venter.
The only form in the Cretaceous that is similar to this is in the young
of Gabbioceras batesi (Gabb). This last has a similar coronate form with-
out any lateral zones throughout the neanic stage, but the sutures show
this to belong to a different suborder, the Leptocampyl, with which it also
agrees in the aspect of the shell and the characters of the adults. f
The sutures have very peculiar broad, short ventral lobes and first
lateral lobes. There is but one broad principal lateral saddle, with coarse
marginal saddles; the lobes and saddles are ammonitic—that is, completely
margined by small lobes and saddles. White’s figure has the sutures very
imperfect and much worn away, but shows the orad trend of the auxiliaries.
It is also defective in regard to the first auxiliary saddle. This is a well-
defined and very broad saddle, smaller than the first lateral, but otherwise
resembling it. The sutures are considerably worn away in the specimen
figured, but the preservation is better than in White’s fossil. The differences
in the sutures and form from its assumed congeneric associates in the Pul-
chellidee can be accounted for if it is assumed that this genus is in its
principal characteristics an arrested development of the coronate form of
the early stages, as stated in the introduction to this paper.
COSMOCERATIDA 103
VASCOCERAS HARTTI (Hyatt)
Pl. XIV, fig. 16.
Ceratites harttii Hyatt, 1870, Geol. and Phys. Geog. Brazil, p. 386.
Buchiceras hartt’i Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p. 370.
Ammonites harttii White, 1888, Arch. Mus. Nac. Brazil, Vol. VII, pl. 19.
Vascoceras ? harttdi Choffat, 1898, Faune Crét. du Port., Vol. I, 2d series, pl. 13.
This fine fossil was received from Prof. J.C. Branner, and was collected
by him not far from the locality of White’s fossil of the same species. It is
a cast, the diameter of the whole is 175 mm., the transverse diameter of the
last volution is 124 mm. The form and general aspect is about the same
as in White’s figure; living chamber of the same length—three-fourths of a
and also other external characters and sutures are as described in
volution
remarks upon the genus; the inner volutions could not be exposed. There
is not the slightest fragment of shell upon this cast, but there are the
remains of the cemented valves of two or three ostreans. With reference to
these I again reiterate the opinions expressed with reference to Hartt’s and
White’s specimens. This cast must, like these, have been a fossil at the
time the ostreans were building their shells, since their valves are attached
to the surface of the cast and fit into the irregularities produced by abrasion
before they began to grow on its exposed surface. It was not a member of
the fauna in which they were found, but came from some earlier strata.
Locality: Province Sergipe, Brazil.
Age: Cenomanian?
TOLYPECERAS? n. gen. Hyatt.
The curious species upon which this is founded, Tolypeceras (Amm.)
marcousanum, described and figured by Pictet and Campiche in their Ter-
rains Crétacés de St. Croix, is represented in the collections of Museum of
Comparative Zoology by a fragment collected by Jules Marcou, near
Nozervy, in Switzerland. This is, however, sufficient to enable me to see
that the sutures of a somewhat younger stage than those figured by Pictet
and Campiche are of the same type as those of Lenticeras, but with shorter
marginals. The first lateral saddle is broad and solid and the other saddles
are also broad and not deeply cut into. The outer volution is 22 mm. in
« ToAtvan, a lump.
104 PSEUDOCERATITES OF THE CRETACEOUS.
diameter through the mesal plane and 20 mm. at the broadest part between
the nodes. The next youngest volution is 9 mm. in ventrodorsal diameter
and 9 mm. broad.
BARROISICERAS Grossouvre.”
According to Grossouvre’s and Redtenbacher’s figures this genus evi-
dently has smooth, compressed young, with a continuous keel. Grossouvre
shows some forms intermediate between those of his involute haberfellneri
and the very discoidal ones figured by Redtenbacher. It is very obvious
that these have no aftinities with Tissotia, unless it may be through the
similarity of the young. The young in this and in Tissotia suggests aftinity
with the so-called Oxynoticeras of the Cretaceous figured by Neumayer.
Apparently the young figured by Redtenbacher is more involute than at
later ages.
The metamorphoses seem to be (1) entire keel, sides smooth, venter
acute, and form involute; (2) costated with entire keel; (3) tuberculated
and costated and keel broken up into tubercles by crossing of venter by
costae; (4) continuous keel again. (See Redtenbacher, Am, Piion., Abhandl-
K.-k. geol. Reichsanstalt, Vol. V, 1873, pl. 23, fig. 3 b, d.)
This group, so fully described by Grossouvre, contains an excellent
series of forms which he largely includes under the single name of B. haber-
fellneri. According to the mode of classification followed in these pages, the
great differences in form and other characters, including corresponding differ-
ences of development between his B. haberfellneri var. harlei and var. des-
moulinsi, indicate distinct species widely removed from each other. It
makes no difference in following out this method whether these are
obviously connected by intermediate forms or not, the sole criterion being
whether the species differ in their form, involution, and other characters
sufficiently to be arranged in a natural series which can be shown to be
parallel or partly parallel with other generic groups about which there is
more complete information.
“This genus is referred to Mammitide in Hyatt’s chapter in Zittel’s Text-book, while in the
original copy of the present manuscript, prepared in 1897, it appears among the Pulchelliide. The
notes on the Pulchelliidse then written are entirely superseded by the pages in Professor Hyatt’s hand-
writing published here, in which the family is much restricted and does not contain Barroisiceras,
Stoliczkaia, Tissotia, nor Neolobites, all of which were included in the original manuscript. These remarks
on Barroisiceras are inserted in the revised manuscript just before Pulchellidee.—T. W. 8.
MANTELLICERATIDA. 105
BARROISICERAS DESMOULINSI Grossouvre.
Barroisiceras haberfellneri: var. desmoulinsi Grossouvre, 1893, Ammonites Craie
supérieure, pl. 2, fig. 6.
A very stout form, with huge nodes and having the continuous keel
until a later stage.
Locality: Near Périgueux (Dordogne).
Age: Coniacian.
BARROISICERAS HAUERI n. sp. Hyatt.
Barroisiceras haberfellneri: var. Grossouvre, 1893, Ammonites Craie supérieure,
pl. 2, fig. 1 only.
This is more compressed than B. desmoulinsi, the nodes are smaller and
more numerous at the same age, and the keel is broken up into tubercles.
Locality: Same as above.
Age: Same as above.
MAIN TH LEC RRA IDAs
MANTELLICERATIDA.
This group was described in Zittel’s Text-book, Cephalopoda, page
587, as the Pedioceratidze, and included only the genera Pedioceras, Douvil-
leiceras, Steuroceras (Odontoceras) Cossmann, and Diadochoceras.- Of these,
Steuroceras should be removed to the Hoplitide. In the young, or
throughout life in primitive forms, there is close parallelism with Phri-
codoceras and other discoidal tuberculated forms of the Cosmoceratide, but
in later stages the large single or imperfectly bifureated costz cross the
venter. All traces of tubercles may be lost at this or a later age in some
forms, but in most species there are at least two rows, one on each of the
ventro-lateral angles. There is never at any stage a row of median ventran
tubercles nor a keel, nor are the ventral coste ever cut through by a
narrow ventral channel, as in Hoplitidee.
« Acompsoceras appears to be an exception in the figure given by Schliter, but that author distinctly
states that no true keel is formed.
106 PSEUDOCERATITES OF THE CRETACEOUS.
METASIGALOCERAS n. gen. Hyatt.
The type of this genus, Metasigaloceras rusticum (Sow.), has been
figured by several authors.* All of these figures, including Sowerby’s,
show a form in section like that of Sigaloceras taylori and two rows of large
tubercles. These are, however, not truncated on the casts as in that genus,
but are apparently hollow spines arranged in two outer lines. There is no
inner line of tubercles. There are the same number of lobes and saddles
on the sides as in Sigaloceras, viz., three broad and rather deep, solid
saddies with corresponding large lobes. The sutures, as figured by Sharpe,
are sufficiently similar to those of other genera in the family Mantelli-
ceratide to show that it can readily be placed in this group. The first
lateral saddles have three long branches, the second lateral is rather narrow
and, although well divided, is club shaped, and the third is broad and
deeply bifid. This outline is more like that of Dowvilleiceras than any other
genus. The dorsal sutures could not be compared. The alternating costz
are tuberculated on the venter of Pseudaspidoceras and smooth in Sigaloceras.
The general resemblances to Aspidoceras are apparently close, but as this
genus has no inner line of tubercles and perhaps no strongly developed
lateral costations at any stage, the comparison fails. It is obviously a
more primitive form than that of Pseudaspidoceras or Diadochoceras.
PSEUDASPIDOCERAS n. gen. Hyatt. ;
This genus is instituted for some Indian fossils which in the adult forms
and ornaments of some species show close parallels with Jurassic Aspido-
ceratide, but the development and sutures place them in the same family
with Diadochoceras. Their forms are discoidal with quadrate volutions,
broad concave venters, flat lateral zones or sides, prominent umbilical
shoulders, and distinct convex, smooth umbilical zones. The cost are
wide apart, cross the venter and have two ventral and at least four lateral
rows of tubercles, two on either side. The young have in the type form
Pseudaspidoceras footeanum (Stoliczka),” stage similar to that of Diadochoceras
nodosocostatum with, however, more prominent alternating costee and more
quadragonal form of whorl.
« Amm. rusticus Sowerby, Min. Conch., p. 177; Amm. rusticus d’Orbigny, 1840, Terr. Crétacé,
pl. 111; Amm. rusticus Sharpe, 1856, Foss. Moll. of Chalk of England, pl. 20.
» Foss. Ceph. Cret. Southern India, pl. 52.
MANTELLICERATID®. 107
Other species of this genus are as follows: Pseudaspidoceras (Amm.)
conciliatum, cunliffi, and perhaps crassitesta Stoliezka;* also Pseudasp.
(Amm.) ewomphalum Sharpe,’ and deciduum, equal Amm. rotomagensis
VOrbigny.’ There is also a stouter species from the same locality as the
last, Rouen, which has the ventral tubercles in close approximation and a
much more aspidoceran aspect than in the usual form. This is Pseudasp.
schliteri n. sp. Hyatt (Amm. rotomagensis Schliiter).”
The fact that this species and Metacanthoplites rhotomagensis (Defrance)
which has a line of median ventran tubercles and a distinct mode of devel-
opment, have been so often published under the same specific name is very
interesting. It shows how close is the parallelism of form between two
widely separated genera, one in the group Cosmoceratida and the other in
the Mamuiitida.
DIADOCHOCERAS Hyatt.
The young of this genus, first cited in Zittel’s Text-book, page 587, has
in its youngest stages a more cylindrical volution and more discoidal form
and slower growth than in Douvilleiceras. The paranepionic stage has a
coronate form with large tubercles and smooth sides, as seen from the
umbilical aspect. At this stage the venter could not be seen. Later lateral
cost appear and a line of very small tubercles at their inner ends. In
the neanic stage there are ventral tubercles situated on the larger costz
and a broad depression occurs between them on the continuous costee that
cross the venter. ‘This depression is not at first present in the intermediate
untuberculated costee, which are continuous laterally and ventrally. Later
in the ephebie stage the intermediate costz disappear on the sides but
remain on the venter and become dichotomous from the lateral row of
tubercles of the larger costations. This may be a matter of individual
variation or it may be characteristic of different species, since in d’Orbigny’s
figure (Terrain Crétac¢, pl. 75) it is not present in the adult, and two speci-
mens that I have handled of the type species, Diad. nodosocostatum d’Orb.,
differ, the costze remaining single in one and becoming dichotomous in the
other. There is also a third row of tubercles developed in this genus on
the umbilical shoulders that is not present in Douwvilleiceras until a later age,
when the associated characters are quite distinet.
«Foss. Ceph. Cret. Southern India, pls. 50-52. @Paleontogr., Vol. X XI, pl. 6.
6Foss. Moll. of Chalk of England, pl. 13. € M416 oxos, a successor.
eTerr. Crétacé, pl. 106.
108 PSEUDOCERATITES OF THE CRETACEOUS.
PEDIOCERAS Gerhardt
Type Ped. cundinamarce, Gerhardt Kreideformation in Columbien, ete.
Neues Jahrb. fiir Min., Geol., und Pal., Beil.-Bd. 11, 1897-98, p. 172, pl. 4,
fig. 7. Age Aptian. A stout, quadragonal, very discoidal shell, with two
lines of outer tubercles and one on the umbilical shoulders, all very slight,
costee linear, but prominent on the sides and crossing the venter, which
is broad and concave. The dorsal side barely covers the outer line of
tubercles. No sutures given. Includes caquesensis and ubaquensis Karst.
DOUVILLEICERAS Grossouvre.
The type of this genus is the fossil figured first by Walch in the
Naturtorscher, Vol. I, 1774, p. 196, pl. 2, fig. 3. This was cited by Schlotheim
in his Beitrage zur Naturgeschichte der Versteinerungen in Taschenbuch fiir
Mineralogie, Jahr. 7, I, p.111, as the type of Amm. mammillatus. The figure
given by Walch seems to apply to the young of the form usually cited by
authors as mammillaris and figured by d’Orbigny under this revised name.
Mammillaris is cited by Grossouvre, without an authority after the name,
as the tyre of his genus Douwvilleiceras in his Ammonites de la Craie
Supérieure, page 26, and the suture alone is given on page 23.
The young of the shells in the genus have after the smooth nepionic
stage highly coronate depressed volutions with broad smooth venter and
a line of spines on the ventro-lateral angles. These are at this time
coincident with the umbilical shoulders, the true sides of lateral zones being
of later age. The umbilical zones at this time are broad and smooth and
convex, reaching from the tubercles to the lines of involution. Faint costze
are developed trom the tubercles in both directions, completely crossing
the venter, and shorter ones on the sides. They appear also to be dich-
otomous at the tubercles. Later these large tubercles separate more widely
and intermediate costee begin to appear, apparently through arrested devel-
opment of some of the tuberculated costz already existing. These have the
same form and tubercles, but are less prominent than those on either side
of them, and sometimes this is carried to the extent of suppressing entirely
the alternate pairs of tubercles. During this stage the lines of ventral
tubercles appear, and those may be, but are not always, smaller on the
alternating cost. Subsequently at some stage the smaller coste and
tubercles become of equal size with the others. The stage with four lines
of tubercles may persist until the shell is one-half to five-eighths of an inch
MANTELLICERATID#. 109
in diameter, but usually another line of minute tubercles appears on what
are to become the umbilical shoulders, and lateral costes and a lateral
zone begin to appear. This occurs before or contemporaneously with the
appearance of another line of tubercles on the ventral costz close to the
already existing ventral lines. In the next stage a third line appears on
the venter next to the last developed, and usually nearer to them than to
the ventro-lateral line of primitive tubercles. At or about the same time
still another line of tubercles appears on the lateral costae midway between
the two lateral lines. This stage of twelve tubercles is succeeded by a
fourteen-tuberculated stage, and in some cases by a sixteen-tuberculated
stage, through the generation of additional lines of tubercles on the venter.
During these later stages the form of the volution changes, losing entirely
its coronate aspect. The venter becomes more and more elevated and
rounded, the costs more prominent, and the tubercles are apt to become
more and more equal in size, so that eventually in some species it is difti-
cult to pick out the primitive lateral tubercles. The stage of neanie age,
in which there are six lines of prominent spines, is exactly similar to the
young of Pseudaspidoceras footeanum as figured by Stoliezka in his Fossil
Cephalopods of the Cretaceous Rocks of Southern India (pl. 52).
This genus includes the species described below.
DovuvILLEICERAS MAMMILLARE (d’Orbigny).
Ammonites mammillaris COrbigny (pars).
Assuming that the young of d’Orbigny’s species on pl. 72 represents
the mammillatus of Schlotheim, it is evident from the collections in the
Museum of Comparative Zoology that his supposed mammillaris given on
pl. 73 is a distinct species. The young have the same crowded costee and
aspect of this species only throughout the neanic stage. In this species
this crowded condition of the costae and the development of additional
rows of crest-like tubercles on the venter seem to continue indefinitely.
In some specimens that can hardly be considered as anything more than
sporadic varieties, there are one or two additional lines of tubercles gen-
erated within the ventral channel, and in our shell a line of faint tubercles
finally appear in the middle of this channel, thus imitating transiently the
ornamentation of a distinct family, viz, the Mammnitidee.
Locality: Cherbourg, St. Croix, ete.
Age: Albian.
110 PSEUDOCERATITES OF THE CRETACEOUS.
DoUVILLEICERAS ORBIGNYI/n. sp. Hyatt.
Ammonites mammillaris VOrbigny (pars), 1840, Terr. Crétacé, pl. 73 (not pl. 72).
Through the neanic stage this species is not separable from mammil-
lare except by its slightly more discoidal form and more prominent tuber-
cles on the venter, but later than this the costze separate as given in
VOrbigny’s figure, through the nondevelopment of intermediate coste.
This gives an entirely distinct character to the ornamentation. One frag-
ment from Cherbourg, in the Koninck collection in the Museum of Com-
parative Zoology, shows perhaps a third species, since this change is much
more pronounced than in the type cited above and occurs at an earlier age.
This genus is represented in North America by Douwv. (Acanth.)
spiniferum (Whiteaves), found in Canada; and there seem to be two
species, the first described in Mesozoic Fossils, Vol. I, pt. 1, pl. 4, and the
second in the same, pt. 4, pl. 35. The differences appear to lie in the
costations and tubercles of the older stages.
Localities: Numerous, western Europe.
Age: Albian.
SCHLUETERICERAS n. gen. Hyatt.
This group has in its type species Schluetericeras nodosoides, described
and figured in Schliiter’s Cephalopoden der oberen deutschen Kreide (p. 18,
pl. 8, figs. 1-4) a neanic stage with compressed, flat-sided, moderately
involute shell that resembles the neanic shells of Metoicoceras and Mantelli-
ceras in aspect and in the possession of six rows of tubercles and a concave,
keelless venter. In the next stage, however, the ventral lines of tubercles
are lost, thus reducing the shell to a quadri-tubereulate stage and much
larger and longer nodes and more prominent single lateral coste are
developed, while at the same time the venter becomes flatter. This is a
degenerative, obviously gerontic change, but it is so distinet from the
similar stages of other genera that it is quite sufficient to characterize the
group. It is from the Lower Turonian according to Schliiter.
Other species of this genus are as follows: Schluetericeras vielbanci of
the Turonian, described and figured by d’Orbigny in Terrain Crétaeé
(pl. 108) as woolgari, but changed in his Prodrome (Pt. I, p. 189) to this
MANTELLICERATID®. a iB |
name. ‘The reference to this genus accounts for the retention ot two lines
of obsolescent tubercles on the flat venter between the large ventro-lateral
spines. Schluetericeras laubei, described by Laube and Bruder in Ammoni-
ten der Bohmischen Kreide* as nodosoides of Schliiter, and Schluetericeras
michelobense occur in the Upper Turonian and are distinet in their forms,
especially their large nodes and costie, and in their tendency to form definite
channels on the venter, from either vielbanci or nodosoides
SHARPEICERAS n. gen. Hyatt.
This genus in its full-grown condition has very nearly the same form
and characteristics as the neanic stage of Mantelliceras mantelli. There are
eight lines of tubercles and the volution is compressed quadrate in section.
The costee, are however, more evenly developed and do not bifureate in the
figures given by Sharpe. ‘These characters are so marked and it is so
plainly a phyloneanic form that it can not be placed in the same genus
with Mantelliceras. Its characters in old age are unknown, but in the
young, according to Sharpe, the costee are dichotomous from the line of
tubercles on the umbilical shoulders.
Type is Sharpeiceras laticlavium (Sharpe), figured on pl. 14 of his
Fossil Mollusca of the Chalk of England (Pt. I, pl. 14).
Sharp. schluetert n. sp. Hyatt, described as Ammonites laticlavius by
Schliiter in Ce phalopoden der oberen deutschen Kreide? is a Cenomanian
species with less rapidly growing and less compressed volutions than in the
English shell. Sharp. inconstans (Schiiiter) is a more involute species of
the same genus, having in its old age, if correctly defined by Schliiter, a
volution precisely similar to that of the genus Acompsoceras. All of these
belong to the Cenomanian
ACOMPSOCERAS:‘ n. gen. Hyatt.
The type of this genus, Acompsoceras bochumense, was described by
Schliiter in his Cephalopoden der oberen deutschen Kreide,” from the
Cenomanian. In the adult stage, as described and figured, it has large
fold-like costze on the lateral zones, with two rows of tubercles, one on the
edges of a flattened venter and the other on the dorsal shoulders. These
@Paleontogr., Vol. XX XIII, 1887, p. 229, pl. 25. © Axouos, unadorned.
+ Paleontogr., Vol. X XI, pl. 7. @ Paleeontogr., Vol. X XI, pls. 1, 2
112 PSEUDOCERATITES OF THE CRETACEOUS.
are exactly like those of Pulchellia. In the aspect of these ornaments and
in the convex venter with its nascent keel or raised line there is also a close
resemblanee to Roemeroceras and even to Buchiceras. But Sehliiter dis-
tinctly states that this is not a keel ‘und der Sipho driickt die Mittellinie
des Bauches etwas in die Héhe, ohne dass jedoch ein eigentlicher Kiel
entstiinde.” In old age the sides become smooth and the venter rounded,
and all traces of tubercles and costz are lost. The sutures have a decided
similarity to those of Sharpeiceras inconstans, and, as stated in noticing that
species, the older stages of this species are similar to those of bochumense,
while the younger ones, including the ephebic stage, have the character-
istics of Sharpeiceras. This implies genetic connection with that genus,
and if confirmed by further observation, settles the origin of the group.
The young are not known, and until these are known it is, of course, ques-
tionable whether the affinities for Sharpeiceras are as close as is assumed
here.
Acompsoceras essendense (Schliiter), described in the work quoted
above, and also from the Cenomanian, is another species of the same genus.
ACOMPSOCERAS RENEVIERI (Sharpe).
Ammonites renevier? Sharpe, 1856, Foss. Moll. of Chalk of England, pl. 20.
This species is from the Gray Chalk (Cenomanian) of England and.
has been referred to as similar to essendense. It is a more compressed form
than either Acompsoceras bochumense or essendense, but has a nascent keel
and two rows of large tubercles, one on the ventral edge and the other on
the umbilical shoulders which are similar. The tubercles are connected by
broad fold-like costa: with intermediate shorter costations that sometimes
bifurcate from the longer ones.
The sutures have a large, deep, and rather narrow ventral lobe divided
by an entire siphonal saddle. The first lateral saddle has three large
marginals, the first lateral lobe is long, rather narrow, and bifid. There are
but three lateral saddles, the innermost of good size and bifid. If this
suture is correctly drawn by Sharpe, it is more like that of Barroisiceras as
figured by Grossouvre than that of Acompsoceras. But until the young is
known, the generic name should be considered uncertain. The sutures also
are not unlike those of some species of the keeled and tuberculated forms
like coupei, ete
MANTELLICERATID &. 115
MANTELLICERAS n. gen. Hyatt.
>
At first sight the type of this group, Mantelliceras mantelli, appears to
belong to the same genus as Metoicoceras, but a slight examination of the
development shows them to be generically separable. The tuberculated
young Mantelliceras approximates to the type of development exhibited by
Douvilleiceras, and is a compressed tachygenic form of the same family.
The adult characteristics also show no close affinities for the Pulchellian
group to which Metoicoceras probably belongs.
The type species can not frequently be separated from Calycoceras “
navicularis, owing to the similarities caused by the continuity of the coste
across the venter and the presence of similar lines of ventral and lateral
tubercles. The development, however, and the forms in well-preserved
fossils are both distinet and their variations lead in different directions.
C. navicularis has the coronate form prolonged in its early stages and the
cost prominent on the venter and a median ventran line of tubercles
during its neanic stage and sometimes later. The furrowing of coste on
the venter is of later development, and if Sharpe's figures and descriptions
in Fossil Mollusea of the Chalk of England, page 39, pl. 18, are correct,
it is due to the disappearance of this line of tubercles. I have not been
able to get the young of this species for study, but that this line of tubercles
is sometimes retained until later is obvious in some specimens that I have
had in hand.
The relations of the young to those of Dowvilleiceras are obvious during
the stage in which the volutions have a very broad ventral channel, with
cost crossing the venter and six rows of tubercles, and before the
innermost and eighth rows arise on the inner ends of the cost. In
the octotuberculate stage they are like the full-grown form of Sharpeiceras
laticlavium. The shell of MW. mantelli is at that time, a middle neanic
substage, very closely similar to Douvilleiceras mammillatum in its sexitu-
berculate stage. No additional lines of tubercles are added in this genus.
On the other hand, the tendency is toward complete suppression of all
except the two ventral rows. These disappear also in extreme age. ‘The
sutures are obviously of the same type as in other genera of this family and
are closer to those of Douvilleiceras than any other genus.
“« KdAvé, calyx. Noted in Zittel’s Text-book, Cephalopoda, p. 589.
ta}
MON XLIV—03
114 PSEUDOCERATITES OF THE CRETACEOUS.
MANTELLICERAS MANTELLI (Sowerby).
Ammonites mantelli Sowerby, 1814, Min. Conch., pl. 55.
Ammonites mantelli Sharpe (pars.), 1856, Foss. Moll. of Chalk of England, pl. 18,
figs. 6, 7 (not fig. 4).
Ammonites mantelli Schiiiter, 1872, Paleontogr., Vol. X XI, pl. 5 (not pl. 6).
The compressed form, with broad venter, and presenting clearly three
facets, with four rows of tubercles, more or less well defined, is obviously
the shell that more nearly than others answers to Sowerby’s description and
figures. This is obviously the form that in the young is the least involute
and has the most decidedly quadragonal volutions, becoming compressed in
later stages. This is the var. (a) of Sharpe, as quoted above.
MANTELLICERAS COULONI (d’Orbigny).
Ammonites manteli VOrbigny, 1840, Terr. Crétacé, pl. 104 (not pl. 103).
Ammonites couloni VOrbigny, 1850, Prodrome de Paléontologie, II, p. 147.
Ammonites mantelli Sharpe, 1856, Foss. Moll. of Chalk of England, pl. 18, fig. 4 (not
figs. 6, 7).
Ammonites mantelli Schliiter, 1872, Paleontogr., Vol. X XI, pl. 6 (not pl. 5).
This is a highly compressed shell, separable even in the neanic stage
from mantelli. The young are much more compressed than in mantelli, sides
flatter, and the form resembling that of the full grown of that species when
the shell is not over three-fourths of an inch, or about 18 mm., in diameter.
The tubercles are present, but much less prominent in the young than in
mantelli at the same age.
MANTELLICERAS PICTETI n. sp. Hyatt.
Ammonites mantelli Pictet et Campiche, 1859, Terr. Crét. de St. Croix, p. 200, pl. 26.
The neanic stage, with its more compressed form, but otherwise like
the young of mantelli, and all stages are finely illustrated by the authors
quoted above. The volutions are more compressed than in manfelli and
somewhat less involute in all stages later than the neanic, and the venter
narrower. The octotuberculate stage is more prolonged and the umbilicus
wider than in M. couloni. In extreme old age the tubercles are all lost and
costs are prominent where they cross the narrow rounded venter. There
are a number of this species and casts of some of Pictet’s originals in the
Museum of Comparative Zoology.
METOICOCERATIDA. i les)
Locality: St Croix.
Age; Cenomanian.
MANTELLICERAS VICINALE (Stoliczka).
Ammonites vicinalis Stoliezka, 1865, Foss. Ceph. Cret. Southern India, pl. 44.
Locality: India.
MANTELLICERAS UsHAS (Stoliczka).
Ammonites ushas Stoliezka, 1865, op. cit., pl. 51.
Locality: Undia.
MANTELLICERAS INDIANENSE Hyatt.
Ammonites mantelli Stoliezka, 1865. op. cit.. pl. 41, 49.
This species is similar to true mantelli, but the shell retains the eight
rows of tubercles and the facetted form until a much later age. It finally
loses these larval characters and takes on the usual aspect, with only two
rows of ventral tubercles and compressed volutions. There are probably
two species under this name. The type of this is fig. 1, pl. 42, a more
ornate shell than any variety of mantelli, with larger tubercles and deeper
depressions on the venter.
MANTELLICERAS DOMEYKANUM (Bayle and Coquand).
Ammonites domeyhanus Bayle and Coquand, Foss. sécondaires ree. dans le Chili,
etc., p. 10, pl. 2, figs. 2-5.
Retains the tuberculate stage until quite large, and in the full-grown
shell, which is of great size, the last volution being 80 and 90 mm. in
diameter in one specimen, there are still six lines of well-developed
tubercles and the subquadrate form of the volution is but little modified
This is by far the most primitive form of this group.
METOICOCERATID Hyatt.
This family is necessarily instituted for a peculiar group of species
whose development does not admit thei within the pale of either Heinzidee
or Pulchellide, but whose later stages show that they belong in the same
group with the latter. The family and generic and to some extent specific
characters are necessarily mingled in the following descriptions:
116 PSEUDOCERATITES OF THE CRETACEOUS.
METOICOCERAS* n. gen. Hyatt.
The young, although distinct from those of Heinzia, enable us to
connect Heinzia and its more modified allies with what I have misnamed in
Zittel’s Text-book the Pedioceratidee,’ here corrected to Mantelliceratidee.
The type species, if the full-grown shells were the sole evidence,
would necessarily fall into the same genus with Heinzia matura on account
of the resemblance of the compressed later stages. But the following
description of the young shows this to be a case of morphic equivalence
based on entirely distinct modes of development.
The earliest stage observed has a coronate form with large lateral
tubercles. This stage is of short duration and appears on what seemed to be
still the nepionic stage at about 2 to 2.5 mm. in diameter. The venter at
this time is broadly rounded and without costz on the cast. Subsequently
at diameter of about 3 mm. the ventral rows of tubercles begin to appear
upon fine costee that pass across the venter and connect the rows of tubercles,
and the coste also begin to spread inward on the sides. The termina-
tions of these at 4 mm. diameter were without tubercles. The costz are
partially bifurcated at the outer row of ventro-lateral nodes, but only one
of each pair passes across the venter. The two rows of ventral tubercles
are borne upon this costation, and in front of each one is a depression or
transverse furrow exactly like those that are so peculiar and characteristic
of Cheloniceras royerianum. Intermediate costee begin to appear a little later
and at first are without tubercles and are single. In this stage there is an
evident modification of a late neanic substage of Cheloniceras, which has
similar costae but a more coronate form. These coste subsequently form a
branch of the dichotomous lateral costations or may remain single and
short. Though the resemblance to Aspidoceras is apparent, the general
form and aspect at this age can be accounted for as a parallelism with Pseu-
daspidoceras of India, which is one of the same stock, and arises as the
result of the assumption of the subquadrate form after the coronate stage
in related organisms. It is of course very likely that this Aspidoceran
aspect may have some genetic significance, but the connections that would
prove this are not as yet clearly made out. One can not accept all of the
characteristics that appear in larval forms as of unquestionable genetic
significance. They are safe guides only when carefully compared and
a Mérotkos, an emigrant. »b See Mantelliceratidee.
METOICOCERATID.®. Lite
systematically handled with due regard to the collateral evidences, deduci-
ble from the later stages of development and the obvious relations of the
adult and even senile stages. Thus in the present case, while the young
would place this genus entirely outside the pale of the Heinziide, the
later neanic and the ephebic stages and old age and sutures sliow them
to belong near that group. The peculiar elongated erestlike tubercles,
the costs, and finally the sutures are of the Pulchellian type. When
these later stages are allowed their full weight, it is then seen that the
development shows Metoicoceras to be the descendant of some common form
from which Carstenia tuberculata and Heinzia provincialis are also descended.
It is also apparent that this must have been either similar to or identical
with some species of the coronate genus described here as Cheloniceras.
The coronate young of Metoicoceras are not reconcilable with the young of
Heinzia nor any other form of this family, so far as known. The develop-
ment of Heinzia differs in the suppression of the coronate stage and of the
sextuberculate stage and the appearance of the approximated lines of tuber-
cles on the venter of the Heinzian type by a tachygenic mode of develop-
ment common in this group. The difficulty of reconciling the development
lies in the fact that the outer rows of tubercles appear later than the ven-
trals and are not developed, like those of Metoicoceras, from a primitive row
preceding the ventrals in development. This may be a case of what Cope
has called retardation of development, but if this is so, the effect is really to
accelerate the appearance of the Heinzian characteristics of the venter.
The sutures of the entire groups of Cheloniceratidze and Mantelliceratidae
are of the same type. The number of lobes and saddles is much more
limited than in Heinziidze or Pulchelliidee, both on the dorsum and externally.
The outlines also are excessively complex, with a certain ragged look due
to their long, subdivided marginals, and also apt to be asymmetrical or trifid
rather than bifid. There is also a noticeable absence of simple entire sad-
dles and lobes in the umbilical region. Comparison of the sutures of
Metoicoceras with those of Heinzia or Pulchellia shows at once resemblances
that are quite close enough to place swallovi in the same group with Heinzia,
and the sutures of Metoicoceras are especially close to those of Carstenia?
tuberculata. The development, being irreconcilable with that of any form
of Heinziidze or Pulchelliidee, shows that the genus can not be placed in
either of these families without confusing the picture of their systematic
and genetic relations, so far as now known.
118 PSEUDOCERATITES OF THE CRETACEOUS.
Merorcocgeras swaLuovi (Shumard).
Pl. XI, figs. 7-24; Pl. XIII, figs. 1, 2; Pl. XV, figs. 1-4.
Ammonites swallovi Shamard, 1859, Trans. St. Louis Acad. Sci., Vol. I, p. 591.
So far as I have been able to see, this species has not been previously
figured, but that described below as whitei has been the one selected as the
typical form of swallovi.
The following quotation from Shumard’s description shows that while
he had in hand perhaps both of the species here described his remarks seem
to apply more decidedly to the one selected as swallovi rather than to its less
prominently nodose and more complex companion. Shumard states “dorsum
[venter] flattened, transversely ribbed, nodose-bicarinate; * * * umbili-
cus deep, exhibiting about one-third of each of the inner volutions and about
as wide as one-half of the width of the last volution.” If he had in hand such
a specimen as the one he mentions as being 6 inches in diameter, and it was
a representative of whitei, this large umbilicus would be just about in this
proportion, but it would be inapplicable to an ephebie stage as a young
specimen of this species. If he had had a specimen of M. swallovi, the
large umbilicus would have been found in the neanic and ephebie stages in
about this proportion. Shumard’s other remarks apply also about equally
well to either species, but the sutures, as described by him, point out quite
clearly the typical form. ‘Dorsal saddle almost double the width of the
superior lateral lobe and divided into two unequal branches by a short
subconical auxiliary lobe; the dorsal [outer] branch having three small
notches, while the inner one is rounded and has usually only a single small
notch at its internal border.” Such simple outlines as these occur only in
the forms here referred to as swallovi, and one of the specimens (PI. XIII,
fig. 2) came from Grayson County, Tex., the typical locality quoted by
Shumard.
The young figured (Pl. XI, figs. 7-15) and the sutures (Pl. XI, figs.
18-23) were taken from a specimen found in a piece of the matrix cracked
off from the specimen shown in fig. 16 and are quite likely the young of
this species, but it is probable that at this age the differences are slight
between this species and whitei. Three specimens were obtained from this
piece of matrix. That to which figs. 12, 13 belonged reached an older
METOICOCERATID.®. 119
stage than figs. 14, 15, and the last node near the umbilicus on this was
considerably larger than the preceding nodes, indicating that this young
one belonged to this species. The breadth of side at this age was about
9 mm., the transverse diameter about 6 mm. The breadth of the side at
the base of the living chamber, which was badly crushed farther on, in
fig. 16 is 20 mm., while the diameter between the tubercles is 16 mm. The
young volution was quadrate in form, the sides parallel, whereas in the
specimen represented by fig. 16, as may be seen in fig. 17, the lateral zones
are highly inclined and the venter much narrower than in the young. In
the fossil shown on Pl. XII, fig. 2, the breadth of the side at the third suture
is about 33 mm., the transverse diameter between the costee being 23 mm.
The outward inclination of the sides in this specimen was not so great as in
the fossil represented by Pl. XI, figs. 16, 17, even at the same stage, and
the nodes near the umbilicus were apparently not quite so prominent.
Besides the marked prominence of the nodes and their dichotomous cost,
the living chamber in the young (figs. 14, 15) is clearly nearly three-
fourths of a volution in length, while in the later stage it appears to be in
part complete and to be one-half of a volution in length. It is obvious that
this species becomes more compressed with increasing age, and has a much
narrower venter and less transverse diameter in proportion to the ventro-
dorsal than in the young. The protoconch has an arcuate venter (Pl. XI,
figs. 7-10) and rounded dorsum, with subangular bend as the outline
approaches the opening of the conch. This opening, doubtless once the
aperture of the protoconch, is much depressed or broad transversely and
continues to have this form throughout the ananepionic and metanepionic
substages. The elevation of the venter begins in the second volution,
fig. 10, but the form remains smooth and the sutures goniatitie until
about the fourth volution.* "Then nodes begin to appear on the ventro-
lateral angles and the venter becomes broader in consequence. The venter
is smooth at this substage, the first of the neanic substages. In the next
substage, about one-half of a volution later, fig. 14, the costee become more
prominent near the umbilici and wrinkles appear on the venter, each
accompanied by a pair of tubercles. In the next substage, which was not
seen, it is probable that these ventral costee become connected with the
lateral ones and equal in number to them, and nodes appear on the inner
«This was guessed at.
120 PSEUDOCERATITES OF THE CRETACEOUS.
ends of the lateral costze and there fuse into more or less dichotomous
forms. This fusion is not as complete in the fossil shown in fig. 16 as it is
in the one shown in PL. XIII, fig. 2, at a later age.
The sutures seem to follow about the same steps in progress of devel-
opment as the external characters. Fig. 11 gives an enlarged sketch of
cecum, which seems small in this specimen and which opens into a large
siphuncle, whose parts could not be studied any further than is visible in
the drawing. Although every effort was made, and this specimen was
remarkably clear and transparent, nothing definite could be made out
beyond the cecum. It is certain that the dark color of the wall of this
body has no posterior prolongation or prosiphonal continuation. The
second septum, beginning the sutures of the metanepionic substage, had
unquestionably a divided ventral lobe, as given in fig. 10. This was estab-
lished by many repeated observations. There were, as usual, but two
broad goniatitic saddles of the Tornoceran type on either side and one
broad lateral lobe on each side, with a distinct saddle at the line of involu-
tion. [was not able to detect any depression, such as I have previously
deseribed in other forms as an embryonal umbilicus, occurring at the begin-
ning of the true conch. In the paranepionic substage the suture becomes
distinetly divided on the sides into two broad saddles, with a lateral lobe
and a lobe at the line of involution on either side, and during this substage
the dorsal suture assumes finally the aspect given in fig. 21. The sutures
(figs. 18-20, 22) belong to the neanie stage, represented in figs. 12-15.
They show the usual mode of division common in Ammonoids of the Jura
and Cretaceous, the incoming of auxiliary inflections on the primitive
second lateral saddle and the primary bifid division of the first lateral
saddle and first lateral lobe, the entire aspect of the siphonal saddle and its
subsequent. bifidity. Fig. 22 of Pl. XI shows the peculiar prolecanitean
aspect of the dorsal inflections before the end of the neanic stage, and illus-
trates my previous statements with regard to the retention of ancestral
characters by these internal sutures. Fig. 23 of Pl. XI and fig. 1 of Pl. XI
are of very nearly the same age, and give the beginning of the ephebie
substages. The latter show that the primitive median marginal lobe of the
primitive dorsal saddle becomes the large marginal dividing the full-grown
first lateral saddles. This suture also shows that the second lateral saddle
has a trifid termination in some specimens of this species.
METOICOCERATID.E. Ln
The sutures in the two specimens here described as swallovi are some-
what abraded, but their details of outline are sufficiently well preserved in
different sutures to enable one to see how much simpler they are than in
M. white’. This simplicity of the marginals is not so great in some speci-
mens as it is in fig. 2 of Pl. XIII, since in the suture (Pl. XIII, fig. 1) the
second lateral is trifid and in fig. 13 the fourth lateral saddle is bifid. The
number of inflections on the sides appears to be less in this species than in
white, five only being present on both sides, with saddles at the lines of
involution; and in the fossil shown in Pl XI, fig. 16, there is the same
number, with a lobe at the line of involution.
Locality: Grayson County, Tex.; Utah.
Aye: Colorado epoch.
METOICOCERAS GIBBOSUM n. sp. Hyatt.
Pl. XV, figs. 5-8.
The single fossil upon which this species is founded could not be
placed in any of the species here described under the same genus. It
has stouter, broader volutions than any of these, and, instead of becoming
more compressed as it grows older, continues the same rate of increase
in the transverse diameters The involution is about the same as in
M. swallovi, but there are no nodes on the umbilical shoulders at. any stage,
although the alternating longer costee reach to the umbilical shoulders.
Their greatest prominence is at a short distance ventrad of the
umbilical shoulder. The costations are like those of the oldest stage of
whitei, i. e., regularly long, prominent coste alternating with short ones.
The two outer lines of tubercles do not differ from those of other
species. The sutures are intermediate between the simpler character
of those of M. swallovi and the more complex outlines of those
of M. whitei. The first lateral saddles and lobes have about the
same general aspect as those of M whitei, but the auxiliaries are
similar to those of MW. swallovi, except that the second lateral saddle shows
small marginals and a tendency to division on its outer side, which has not
been observed elsewhere. The third lateral saddle shows in some sutures
of the left side a tendency to become divided, which is necessarily
exaggerated in the drawing and which is entirely absent in many sutures,
122 PSEUDOCERATITES OF THE CRETACEOUS.
.
both younger and older than the one drawn. The dorsal sutures could be
seen only from above and in a fragment of the cast of the last camera,
which is not included in the figures given. It was evident that the
antisiphonal lobes resembled those of M. swallovi and Heinzia in being
elongated and considerably telescoped into each other. The saddles also
were similar, especially the first dorsals, which were narrow, long,
phylliform, and deeply cut into by the marginals, as in Heinzia matura.
There was also a similar broad pair of second lateral dorsal saddles; these
certainly had one marginal lobe and perhaps two, being perhaps trifid, but
very flat on their bases. The remaining saddles were entire. There were
apparently five saddles and four lobes on the right side and six saddles and
five lobes on the left side, corresponding to the differences in number of
the external auxiliaries on the same sides. The overlapping of the sutures
is noticeable in this specimen, but whether it can be considered
characteristic of the species is doubtful. The whole diameter is 85 mm.
The last volution on the face of the septum from the center of the venter to
the line of involution is 50 mm.; the ventro-dorsal diameter is 35 mm.
The amount of involution at this point is two-thirds of the breadth of the
side of the next inner volution, bemg 17 to 27 mm. he umbilicus, in
consequence of the smoothness of umbilical zones and the nonextension of
the coste internally, has a smooth, funnel-like aspect, entirely distinct from
that of M. swallovi, although it is nearly of the same size and differs
therefore from that of white’ in being much larger as well as smoother.
Locality: Texas.
Age: Colorado epoch.
METOICOCERAS WHITEI n. sp. Hyatt.
Pl. XII, figs. 3-5; Pl. XIV, figs 1-10, 15.
Buchiceras swallovi White, 1875, Geog. and Geol. Expl. and Sury. West of 100th
Meridian, Vol. IV, p. 202, pl. 20, figs. 1 a-c. -
Buchiceras swallovi Stanton, 1894, Bull. U. S. Geol. Survey No. 106, p. 168, pl. 37;
pl. 38, figs. 1-3.
The external characteristics of this species, in comparison with I.
swallovi, consist in more compressed volutions without such prominent
nodes on the umbilical shoulders. They have nodes, but these are more a
part of the costs and less prominent, the sides are consequently flatter
than in swallovi. ‘There is a decided tendency in the Texas specimens to
METOICOCERATID.©. 123
have the umbilicus smaller and the inner row of the two outer lines
of tubercles elongated longitudinally and parallel with the outer rows.
The sutures are more complex at an earlier stage and remain more
complex throughout life as regards their marginal digitations. The
first lateral lobes are also narrower and longer in proportion in’ the
later stages than in swallovi, and the inflections are more numerous
at the same age, being from six to seven, instead of five or six as
in swallovi. The youngest stage seen (PI. XIV, figs. 1,2) had a living
chamber complete near the umbilicus and not quite three-fourths of a
volution in length. Several specimens showed a completed living
chamber near the umbilical shoulders and on the sides, and in adults it is
much shorter, invariably one-half of a volution in length. The sides
were smooth and flat at the beginning of the outer volution in this specimen.
The costze appeared as shown in the figure and nodal termini were devel-
oped on the last costation near the aperture. These were also present in
the specimen shown in fig. 4, but, as may be seen in figs. 2 and 5, these were
not prominent as in swallovi. The same is true of all of the seventeen
specimens examined besides Pl. XIII, fig. 4 The elongated second row of
lateral tubercles found in fig. 4 is also perceptible to some slight extent in
the specimen fig. 7, but is absent in younger stages and is not present at
any stage in some specimens. This second row of tubercles may be very
slightly developed in some specimens, and the coste are also. much less
pronounced and the venters narrower than in those figured. The other two
specimens show a much stouter form with broader venters and more promi-
nent cost. These can only be separated from true swallovi by their costa,
flatter sides, and less prominent umbilical nodes.
An old suture of this species is shown on PI. XIII, fig. 5. This was
the basal suture of a fragment of the living chamber of a fossil of about
the same size, probably, and age as the one shown on Pl. XIII, fig. 4.
The differences of this suture appear to be considerable when com-
pared with Pl. XIV, fig. 8. The external characters of this fossil are
equally decided, but the absence of the internal volutions and the
variability of the sutures in this species does not justify the
separation of this as distinct from whitei.. The latter part of
this living chamber and the whole of another larger fragment has
huge fold-like cost that cross the venter, cutting it into waves. The
cost are flat on the venter with abrupt forward edges. The ventro-lateral
124 PSEUDOCERATITES OF THE CRETACEOUS.
tubercles and the second lateral row disappear on these coste. The
decrease of the involution through shrinkage of the later diameters is
greater in this than in the old age of the specimen shown on PI. XIII,
fig. 4. Breadth of the side from line of involution to the siphonal saddle
at the suture figured is 65 mm. The length of the living chamber on the
outside or venter is 190 mm. and apparently complete, and the breadth 75
mm. In the specimen shown in PI. XIV, fig. 7, the normal rate of increase
is from 50 to 70 mm. in the same distance measured along the venter, and
in the living chamber of the fossil shown on PI. XIII, fig. 4, which is of the
same length on the venter it is from 70 at the base to 80 mm. near the end:
In both of these old specimens the length of the living chamber and
decrease in the rate of growth was therefore about the same and about
one-half of what it was in the fossil shown on Pl XIV, fig. 7, which was
also an old specimen but was measured along the septate and. therefore
younger portion of the outer volution. The increase by growth previous
to this must have been greater still. The broadening of the venter
noticeable near the aperture (figs. 3 and 4), the spreading of the costz
across the venter, and the loss of nodes are the same in all three of these
specimens and show them to have entered upon the last or paragerontic
substage or decline. The youngest suture examined in this species is
shown in Pl. XIV, fig. 8, from the left side, and this has fully entered the
ephebie stage and is already more complex than those of swallovi at a, much
later age. The corresponding suture on right side of the same specimen is
similar, but the third lateral saddle was quadrifid instead of bifid and
the fourth lateral was more distinctly bifid and phylliform. The matrix of
this fossil from Elm Fork, Tex., was a gray limestone, whereas that of the
specimen shown (fig. 9) was a red clayey limestone, but from the same
locality. The suture was much older, but nevertheless had simpler third
and fourth saddles on both sides of the outer volution. The position of
the suture of the specimen shown in fig. 7, given in fig. 8, is indicated in
fig. 7 by a straight line near the venter, but the sutures throughout this
volution have the same outlines. This and fig. 10 are the most complex
of the full-grown sutures observed in this species.
Fig. 10 was taken from the left side of Pl. XIII, fig. 4, and shows
the outlines of about the same age as in Pl. XIII, fig. 8. The shell was
stripped from a part of the fossil shown in Pl. XIII, fig. 4, also, and the
corresponding suture on that side also observed. In this way it was found
METOICOCERATID.®. 125
that the sutures on the two sides differed considerably. They were alike
in their first and second lateral lobes and saddles, but the third lateral
saddles were simpler on the right side, the side given in Pl. XIII, fig. 4, in
having the marginals less distinct and the fourth lateral was entire instead,
of being bifid. The outlines internally were the same and there were
seven saddles and seven lobes on each side, and saddles at the lines of
involution. The differences between the more fully developed sutures
on the left side, those of the right, and the oldest suture showed similar
degenerations, the saddles becoming much shorter and broader in propor-
tion and the marginals less distinct.
The table on page 126 gives an account of the variations observed
in the sutures. It will be observed that the first lateral lobe is quite
generally bifid, but in the largest specimen (PI. XIV, fig. 8) from Elm
Fork, Tex., it is sometimes trifid. It is very obvious that this character-
istic may be capable of two translations, some of the first lateral lobes in
this specimen being made trifid by a slight enlargement and extension of
the main terminal marginal lobe.
The second lateral lobe varies from simple primitive form of bifidity
to trifid without regard to age, but in most specimens it is bifid. The third
lateral saddle is bifid or trifid without regard to age, but tends to become
quadrifid in older stages. The fourth varies from entire to bifid or trifid,
but in most cases is bifid or trifid. he fifth varies from entire to bifid or
trifid, but is in most cases entire, sometimes bifid but rarely trifid. The
number of lobes and saddles on the sides varies from 11 to 14 in the early
ephebic substages and from 13 to 16 in the full grown.
No. 6 is taken from a fossil with a notably stouter volution, more
prominent coarser cost, and larger tubercles than any of its companions
of the same size from the same locality, Elm Fork, Tex The whole
diameter of this fossil when complete was probably not less than 63 mm,
and the living chamber of the usual length, a little over half of a volution.
Unluckily, like all others of this species, the aperture has been badly
broken and the: rostrum could not be observed. I at first thought this
exceptionally stout and more coarsely ornamented specimen must be a
different species, but the sutures, when laid bare, were identical with
others here described as M. whitei, especially close to that given on Pl
XIV, fig. 10.
126 PSEUDOCERATITES OF THE CRETACEOUS.
Variations observed in sutures of Metoicoceras whitei.
[The number of saddles and lobes represents one side only, All except Nos. 11, 12, and 15 are from Elm Fork, Hortons
mili, Dallas County, Tex.; No. 15 is from Utah; no locality is given for Nos. 11 and 12.]
ieee al | Second Third 1 | Fourth | Fifth lat-| Number (fades
Speci- Si suture irst lat- econ 1rd lat- our 1 at- f ddl ‘Of 8a: es 3
men. jobeerved.| JUNO, eral obe.| Jateral /eralsad:| lateral Jeralsad- Snopes and Jobes| igure,
| oilnidans | on sides. | san
= |
| mm. | | |
sleit... » sbifid ..| Trifid . Trifid | Bifid ../ Entire. IIR ee ‘
becorce \Right If i V6 leo s2|-- do.@2|-2=do'=-| (2) 11 } va oe Gee
x pLeft...}) 13 (Bifi? | @) | .--do ..| Entire? (?) (2) hy 5 aie
ira ake \Right .f Ae) (Qe eed ones | sand onze im) @) (
Left...) ” jBifid!--| (2) |---do --| Drifid - Entire. 14 }) fe PL XIV.
pape eel ik (2) (?) (2) (2) (2) @) VJ *) see
reac eieaa array OL | Lg ie
Shee \Right 5 i (?) (2) Trifid.«) Trifid | Trifid . 1 |
5 cea Saale Male Ae) (?) (?) (?) (?) \ (2)
apa (Right . | ~ | (2) | Bifid ..| Trifid .| Bifid ..] Entire.| (?)
Left...) | Bifid ..|...do ..| Bifidg.|...do ..|...do-.} 13 }
Ge 4 |t 93 | | (2)
(Right J UE@) (?) (?) (?) (?) (7) JJ
: eae 58 { (?) (?) Bifid ..| Trifid? | Entire- 11 \ (2)
arr sie) \Right - IL (2) @): | @ (2) (2) (?) j
of lr (2 2 | (2 ? 2 2)
a ee OIC TO LO VO alla sae
Brpecb Wega *” \Bifid ..| Trifid .) Bifid 0.| Trifid .| Bifid .. 13 J : és és 2
; jleft..}) 4, , (2) (2) | Trifide] (2) (2) (2) fh ) ene
PS (Right |S (2) (2?) |...do.¢.| Entire.| Entire. 139 |
“a Left...) 35 \pBifid = =| Bitid)=3|-Bifid 2|5--do=s|==-dors 16 |) @) | PL XIV
Popa \Right .// \eSdom -|sa2done| saad ote seed ones | eae ones 16 |f aoa 3
rises ESI gp pedo -}---do..| Trifid /.-do..|.-do-.} 18 oust
ae a | (Right - ee | eedoree | Ssadorsleeedoias| seed omelet one 137/J
16 eect ve f--d0 sale (G0) Eccles o-loe6ho) oclle-26'0) 5 all Q)
Sa Right .. > @) (2) |.--do..| (2) (2) 1375 -“"
Left. -- Bifid ..| Bifid ..]...do.@_] Bifid ..| Entire. 1
Sater f 4 5B bi d ifid do i “ ntire 5 \ (2) | Pl XU,
Right - Lido --|---do .-|-.-do.¢.| Waria- |...do .. 15 figs. 3,4
ble.f ay ge
and Pl.
XIV, fig.
; 7 ; : 10.
14 eee 6s \f--do ..|...do ..) Bifid ¢.| Trifid .| Bifid -- 15 \ @) |p. xT
Pits \Right - UL (@) (?) (?) (?) (?) (?) fig. 5 ,
Fe fe zo sBifid ..| Bifid | 4fid ..) Trifid | (2) eal Abilis ee
inte Right - ‘U.do ..|...do ..]...do.9.| Bifid ..| Entire. MILE pe the ss of
| | | SMASE
a Beginning to become quadrifid, i. e., haying four minute marginal saddles by division of one of the bifid marginals,
With a few minute digitations beginning to appear.
eWith three other very minute lobes, five marginal lobes in all.
aDistinetly trifid.
eObscurely trifid.
J Some entire, others obscurely trifid.
g With a number of small marginals just beginning.
METOICOCERATID.®. PAE
In all of these specimens the first lateral saddles were of very nearly
the same general character, decidedly deeply bifid, even in the youngest
stages recorded, and with both arms subdivided by one or more marginal
lobes; the second lateral saddles were also complex at all stages observed,
and one small specimen not recorded in the table, with suture lines on the
last volution running from 12 to 18 mm., showed the same facts. This has
bifid first and trifid second lateral lobes, with quadrifid third lateral saddles
on both sides. A bifid fourth is visible on the right side when the volution
is less than 12 mm. ‘This same saddle with a bifid base is the only one
visible in another fossil with a suture line of about 8 mm. It is evident
that the law of variation in the sutures is that lobes and saddles increase
in variability of outlines and in number progressively from the venter
toward the dorsal lines of involution, the so-called auxiliaries or derivatives
of the primitive second lateral saddles of the young being far more variable
than the first lateral saddle.
Locality: Kanab Valley, Utah; Elm Fork, Dallas County, Tex.
Age: Colorado epoch.
METOICOCERAS ACCELERATUM n. sp. Hyatt.
Pl. XIV, figs. 11-14.
I at first thought this to be the young of the species described by
Whiteaves as Placenticeras liardense, but the figures given by him merely
indicate that the venter had continuous coste across it. The condition of
his fossils was, however, such that he did not see the venter, and this
ean only be inferred from the lateral aspect as given in his drawings.
Apparently there were no tubercles on the sides in the full-grown specimen,
and the umbilicus was about the size of that of M. white and not so small
as in this species. There were no nodes nor prominent coste near the
umbilical shoulder in this fossil, and the two outer rows of tubercles were
much less prominent than in the preceding species. The venter in the
first half of the outer volution resembled that of MW. whitei at an earlier age
on the first quarter of the outer volution of the specimen shown in Pl. XIV,
fiz. 1, but with less decided tubercles, and on the latter half of this volution
it is changed as the venter is in the old age of M. whitei. That is to say,
the cost that cross it are prominent and flat, but not channeled nor
concave. The cost on the sides are not so prominent and coarse as in
128 PSEUDOCERATITES OF THE CRETACEOUS.
whitei. There are more of them, and only the last begin to reach entirely
across the sides. ‘There is a sigmoidal channel on either side that does
not reach across the venter. This is a characteristic occurring also in
M. liardense, but not in other species. This occurs close to what must have
been the edge of the aperture, since the living chamber is considerably
over three-fourths of a volution in length and was probably a little longer
when complete. The black line shows the position of the basal septum of
the living chamber shown on the opposite side of the fossil figured.
Locality: Elm Fork, Horton’s mill, Dallas County, Tex.
Age: Colorado epoch.
HEINZIID/AZ.
The members of this family are easily distinguishable from the typical
Pulchelliide by the possession at some stage of elongated, usually
double, but more or less connected tubercular terminations on the ventral
ends of the lateral costae. All of the forms so far known have coarser and
more complete lateral costee than are usual in Pulchelliidze, and there is,
especially in primitive forms, a tendency to the development of stouter
yolutions, with less involution and consequently wider umbilici. The
average size is larger, and the development is very distinct in all forms, so
far as known. The young are stouter, less involute, and have costa con-
tinuous across the venter. The tubercles appear upon these cost in two
lines of single tubercles, and then subsequently two rows are developed
upon the outer sides of these that remain more or less closely connected.
The lateral coste are similar to those of Pulchelliidae, but sometimes a
median or an inner row of tubereles or both appear in the later stages.
The ventral channels are apt to be real channels furrowing both the costz
and the intercostal spaces on the venter, and in the young and in primitive
forms are apt to be narrow and smooth. The sutures are similar to those
of Pulchelliidze, but as a rule have fewer and larger saddles and lobes, and
the outlines more complex at the same comparative age, judging from the
size of the casts.
The development is so distinct from that of Pulchelliidee in some species
of Heinzia that if it were not for the fortunate accident that placed one
specimen of Heinzia matura in my way, I could not have offered any
rational suggestion as to the true relations of this family. The development
of Heinzia matura, however, shows, as stated below, a form that in the
HEINZITD 2%. 129
young is involute, smooth, and compressed with a rounded venter as in the
young of Pulchelliidee. Then it has a faint line of ventral tubercles and
flat venter followed by a true Pulchellian stage with channeled venter
bordered by single tubercles. In other words, at this age the species is
like Pulchellia except that the tubercles are not elongated crests. The
ephebie stage shows the usual terminal double row of tubercles of the
Heinziide. The conclusion from this evidence is that the Pulchelliidze
probably arose from Heinzia or some very similar form through the increase
of compression and involution and from the prolongation of the smooth
larval’ stages, the suppression of the preliminary lines of ventral tubercles
in the young and the tendency in later stages to suppress the second lateral
lines of tubercles. This inference acquires some support also from the fact
of the earlier appearance of Heinziidie in the Neocomian. We can in this
way account for the communal resemblances of these two families in their
adult forms, costae and sutures, but it must be borne in mind that the evi-
dence upon which this inference is based is not by any means complete.
The evidence with regard to the connection and genesis of forms is
less complete than in the Pulchelliidae, but the following diagram gives the
apparent relations of the genera so far as the ontogeny at present known
indicates these:
Metoicoceras
Gerhardtia Carstenia
—Heinzia
. Cheloniceras
HEINZIA Sayn.
Sayn® defines this genus in the following terms: ‘Les espéces qui se
rattachent aux Pulchellia subcaicedi et provincialis sont nettement caractér-
isées par une ornementation vigoureuse, visible dés les tours embryonnaires,
un accroissement en général moins rapide, des sutures le plus souvent trés
éloignées les unes des autres et remarquables par le grand développement
en largeur des selles et l’amoindrissement des lobes trés ¢troits et peu
découpés.” The group described by Sayn under this name is obviously a
aAmm. du Barrémien du Djebel-Ouach prés Constantine: Ann. Soc. d’ Agriculture de Lyon, 6th
series, Vol. III, 1890, p. 151.
MON XLIV—03——9
130 PSEUDOCERATITES OF THE CRETACEOUS.
composite of several genera distinct in their development and in their
sutures from any form of true Pulchelliidee and also differing decidedly
from each other. The species here mentioned as H. sayni is assumed to be
the type because it is one of the first two species mentioned by this author
and is the first one of these figured. His Pulchellia subcaicedi appears to
me to belong with Pulchellia caicedi (Karsten) in the genus Carstenia.
HEINZIA SAYNI Hyatt.
Pulchellia provincialis Sayn, 1890, Ann. Soc. d’Agriculture de Lyon, 6th series,
Vol. III, pp. 165, 166; pl. 1, fig. 16; pl. 2, fig. 7.
This is neither the species figured by d’Orbigny nor that given by
Nicklés, but a dwarfed, compressed form with fine tubercles and fine costz
developed at a comparatively early stage. It is similar to true H. provin-
cialis in being less involute than corioli.
Locality: Djebel-Ouach, North Africa.
Age: Barremien.
. Hernz1a cortour Nicklés.
Pulchellia (Heinzia) corioli Nickles, 1890, Mém. Soe. géol. France, Paléontologie,
No. 4, p: 53, pls. 6, 7
This species and another, supposed to be allied to sayni, are both
larger, have coarser ornaments and more complex sutures than the African
forms, and broad channels like Gerhardtia. f
Locality: Spain.
Age: Barremian.
HEINzIA HEINZI Coquand.“”
Pulchellia heinzi Sayn, 1890, Ann. Soc. @ Agriculture de Lyon, 6th series, Vol. IIT,
pl. 2, fig. 5.
This species has similar ornamentation, but much coarser than in
H. sayni. The sutures are given, and these are not similar to those of
Pulchellide.
Locality: North Africa.
Age: Barremian.
«Coronites is represented in North Africa by a small group of dwarfed forms having the develop-
ment and general aspect of the more discoidal forms of Hoplites. The type is Cor. (Heinzia) coronatoides
(Sayn). This form has a ventral channel, beginning at a comparatively early stage while the young
are still highly coronate and the costze dichotomous on the venter. These spring from singie nodes cn
the latero-ventral angles, which are coincident with the umbilical shoulder. These subsequently
HEINZIID®. ile) il
Heinzia HISPANICA n. sp. Hyatt.
Pulchadlia (Heinzia) ct. provincialis Nicklés, Mém. Soc. géol. France, Paléontologie,
No. 4, pls. 6, 7.
Nicklés’s figures give a species with smaller umbilicus and a shallower,
wider channel turrowing the costz only, as in Pulchellia. The costa have
more prominent nodes and are more prominent on the venter, which is
crossed by them and cut up into waves as in Pulchellia.
There is one specimen in the Museum of Comparative Zoology, prob-
ably trom Escragnolles, that I have labeled Heinzia att. hispanica. It
differs from this species only in having more involute whorls and perhaps
somewhat coarser costae and possibly the sutures a little more complex.
HeINZIA PULCHELLIFORMIS n. sp. Hyatt.
This species, from the collection in the Museum of Comparative Zoology,
has exactly the form and aspect of some of the typical species of Pulchellia,
except that the coste are more prominent and cross the inner parts of the
sides, and the outer row of tubercles has the broad, double character of
those of the Heinzia group. This has no inner line of tubercles and has
beew considered similar to didayanus, which is a species of Nicklesia.
Locality: Escragnolles, France.
Age: Barrémian.
Hernzia PROVINCIALIS (d’Orbigny).
Pl. XV, figs. 19,20; Pl. XVI, figs. 1-3.
Ammonites provincial/s VOrbigny, 1850, Prodrome de Paléontologie, Vol. Il, p. 99.
Pulcnellia provincialis Uhlig, 1883, Denksch. K. Akad. Wiss., Wien, Vol. XLVI,
pl. 20, fig. 2.
Assuming Uhlig’s figure to be taken from a species identical with
VOrbigny’s, the specimen here figured is a true representation of this
extend internally into lateral single coste: and the nodes disappear. The costee become single on the
sides or may remain dichotomous. The result is a form in some species that is almost an exact
parallel with some forms of the Hoplitidee. The sutures are simple and have an immature aspect.
The ventral is rather narrow and is divided by a small truncated siphonal saddle. The first lateral
saddles are very broad, bifid on one side in H. hoplitiformis and trifid and still broader on the other.
The first lateral lobes are narrow and trifid or bifid. Thesecond lateral saddles belong to the auxiliary
series, and are much smaller than the first and only slightly dentated, while the third and fourth
saddles are entire. The second lateral lobe is very short and entire,and two other similar smaller
lokes complete the lateral line.
This description is taken from Sayn’s figures.
132 PSEUDOCERATITES OF THE CRETACEOUS.
species. It has the narrow, deep, smooth ventral channel, which is also
shown in Uhlig’s figure, with the same peculiar abrupt ventral terminations
to the costze with forward bend on the edge of the channel. The venter is
not cut up into waves by the crossing of the costae as in H. pulchelliformis.
The channel, in fact, is deeper than the depressions between the costze, and
the ridges that guard it on either ridge give a pointed aspect to the forward
terminations of the costze. This is also observable in Uhlig’s figure.
On splitting this specimen I succeeded in exposing three substages
of neanic age. The first substage showed faint costz that crossed the
rounded venter, the form being at this time rounded, with gibbous sides and
open umbilicus. Then faint tubercles appeared, the venter still remaining
rounded between them. These tubercles in the next substage became more
prominent, and the venter between them became flattened. The costz
became more prominent at the same time on the outer half of the side and
made a slight forward bend on to the venter. Soon after this a very faint,
narrow, linear depression indicated the beginning of the ventral channel.
I was not able to discover at what age the second range of tubercles began
to come in nor their exact position. The volution is gibbous on the sides
throughout these early stages and is a rather stout young form with an open
umbilicus.
Locality: Escragnolles, France.
Age: Barremian.
HEINzIA MATURA n. sp. Hyatt.
Pl. XV, figs. 12-18.
This species is allied to that described above by Sayn. It is similar
in its compressed form, in the amount of involution and in the broad
ventral channel, and in having a row of tubercles on the umbilical shoul-
ders. The costze are, however, much broader and have the double external
termination of the group of Heinzia. This termination is, however, not
distinguishable on the earliest part of the outer volution, but is well devel-
oped on the third quarter of this volution. This termination is seen in this
specimen to be a modification of the ends of the costee, and it is not due to
the approximation and coalescence of an inner row of tubercles with the
outer row. The shell is preserved on one side of this specimen and shows
HEINZID.®. 133
the same markings as on the east. The young is much flatter and increases
faster in the abdomino-dorsal diameters than in other species of Heinzia and
remains smooth until a later age. The tubercles appear also later on the
venter, and there is a flat ventral zone for a more prolonged stage than in
H. provincialis, and the ventral channel appears later. The umbilical
tubercles appear on the last volution figured and are at first single. Then
they probably become [double] by the development of two other rows of
tubercles near the ventral lines, but this was not actually seen on the
specimen.
Locality: Escragnolles, France.
Age: Barremian.
HerINZzIA OUACHENSIS (Coquand).
Pulchellia owachensis Sayn, 1890, Ann. Soc. @Agriculture de Lyon, 6th series,
Vol. III, p. 157, pl. 1, fig. 15 (not fig. 1+).
This species, described as a Pulchellia by Sayn, is an involute com-
pressed form probably in the same genetic group with H. matura. This is
shown by the ventral channel and costze and tubercles on the umbilical
shoulders. It has not the broad double terminations of the costze observed
in H. matura. Fig. 15 is probably a true Pulchellia, and is cited under that
generic name as P. kiliani.
Locality: Djebel-Ouach, North Africa.
Age: Barremian.
CARSTENIA n. gen. Hyatt.
This remarkable group has, as shown by Karsten’s figure of Carstenia
lindigt in the latest neanic or early ephebic stage, coarse costze with double
terminations becoming dichotomous at the middle lateral line and having a
line of nodes at their junctions. These are continued later on the singie
costee when these appear. The arising of the double line of outer tubercles
close together on the ventral line is also shown in this figure. The form is
stout in the type mentioned above and similar to that of Heinzia provincialis,
but in the Carstenia (Amm.) caicedi Karsten it is more involute and com-
pressed. The ventral furrow in Carstenia lindigi in the young is narrow
and similar to that of Heinzia, but later it broadens and becomes similar to
134 PSEUDOCERATITES OF THE CRETACEOUS.
that of Gerhardtia. This occurs in an earlier age in Carstenia caicedi.
Descriptions are wholly taken from Karsten’s figures."
CARSTENIA SUBCAICEDI (Karsten).
C. subcaicedi (Karsten) is described by that author as having heavy
coarse coste bifurcating like those of caicedi and, if his small figure
represents the young or a primitive dwarfed form of this group, it shows
how very distinet its development must be as compared with that of other
genera.
CaRSTENIA ? TUBERCULATA n. sp. Hyatt.
C.? tuberculata (Pul. provincialis Gerhardt)’ is described by that author
as identical with lindigi Karsten. It is, however, less involute, and,
although having similar quadragonal volutions, has costae like those of
Gerhardtia and there is no median lateral line of tubercles. The sutures
are more like those of Metoicoceras than of Heinzia provincialis. It is
possible that the development of this species may show it to be more nearly
related to Metoicoceras than to Carstenia. It has, however, the peculiar
channeled bases of the second row of tubercles on either side that have
been found so far only in this last-named genus. All of these have been
supposed to be of Barremian age. Its characteristics seem also to ally it
decidedly with such forms as Heinzia provincialis, and to indicate a'common
origin for all of these genera in some primitive form with similar but more
tuberculose volutions. It is obviously a more primitive form than Heimzia,
which has more compressed and often more involute shells and retains in
its latest stage the form and aspect of the young of H. provincialis and of
the earlier neanic stage of Metoicoceras swallovi. The resemblances to
Gerhardtia are also close, as may be seen on Gerhardt’s plates, and its
form is similar to the young of Carstenia caicedi as figured by Karsten.
These affinities and its obviously primitive larval characteristics show
it to be the nearest approach yet found of the probable genetic ancestor of
the Heinziide.
«@Géol. de l’ancienne Colomb. Venez. Nouv. Gren. et Ecuador. Berlin, 1886.
>Kreidef. in Columbien: Neues Jahrbuch fiir Min., Geol., und Pal., Beil.-Bd. XI, 1897-98, p. 152,
pl. 2, fig. 8.
HEINZIID.®. 135
Carsrenta GaLeata (d’Orbigny).
Ammonites galeatus VOrbigny, 1842, Voyage dans Amérique méridionale, Vol. III,
pl. 17, figs. 3-5 (not figs. 6, 7).
Pulchellia caicedi Gerhardt, 1897, Neues Jahrb. fiir Min., Geol., und Pal., Beil.-Bd.
Sp Lode ply 35, fio.
This species has a form, costs, ventral channel, and outer tubercles
similar to those of C. caicedi Karsten, but having the single costee appearing
later, the double outer line of tubercles disappearing at the same time, and
no median lateral line of tubercles apparent in d’Orbigny’s figures. The
double outer tubercles are observable in figures given by d’Orbigny at the
beginning of the outer volution and are quite plain upon an excellent cast
of this fossil from Chile in De Koninck’s collection in the Museum of
Comparative Zoology. Figs. 6 and 7 of d’Orbigny are true Pulchellia, not
the young of this species. Pul. caicedi Gerhardt has exactly the form and
aspect of the next younger parts of the volution figured by d’Orbigny and
observable on the last mentioned.
GERHARDTIA n. gen. Hyatt.
The near alliance of this genus with Heinzia becomes apparent upon
comparison of the type Gerhardtia galeatoides (Karsten) with Heinzia
provincialis (VOrb.) and Heinzia ? tuberculata. The umbilical characters
are similar so far as the amount of involution and the general aspect is
concerned, but the umbilical shoulders are more prominent, the umbilical
zone is sometimes concave, broader, and the umbilicus deeper. The shell
in the neanic and adult stage is more compressed and more involute than
it is in Heinzia at the same age and also more involute than its own
ephebic stage. The extreme decrease of involution in old specimens may
also be noticed in these forms. The costz in the neanic stage are much
finer and more closely crowded than in any genus of this group. The
coste are similar, but the outer row of double nodes are absent or only
very faintly expressed. The sutures are more complex in outline, but of
the same general type.
The form is more compressed, the venter more contracted, and practi-
cally bounded by the elongated single nodal termini of the coste. The
furrows between the costee cross the venter, cutting it up into flexures, and
the ventral channel is very broad and affects the flexures only, not descend-
ing to the level of the ventral furrows.
136 PSEUDOCERATITES OF THE CRETACEOUS.
.
Besides the type mentioned above, this group contains Ger. galeatus
(Karsten) (von Buch’s figure of this species is too poor for comparison), and
Ger. veleziensis n. sp. Hyatt (Pul. didayi Gerh., op. cit., pl. 3, fig. 4). Amm.
didayanus VOrb. belongs to genus Nicklesia. Amm. didayanus Karsten is
probably a younger stage of the species figured by Gerhardt, and it came
from the same locality, Velez.
Similar species have been cited from other countries by Gerhardt, but
these are unknown to me.
All species are of Barremian age and found in Colombia or Chile.
The sutures have been well figured by Gerhardt and are quite different
from those of C. tuberculata and H. provincialis.
PULCHELLIID/.
This family has highly involute compressed shells. The costee, when
these are present, are acquired at a comparatively late age, and the tuber-
cles, when present, are single elongated crests on the ventro-lateral angles
of the costee. The coste usually cross the venter even when there is a
channel on their outer surfaces. The sunken intercostal furrows that cross
the venter also are not as a rule affected by the channeling of the costze.
The sutures are of the same type as in Heinzia, but with somewhat
more complex outlines. I have had no opportunity to examine the dorsal
sutures. ;
The primitive form is Psilopulchellia,* which retains the smooth keelless
condition of its own young throughout life. This stage is transient in the
development of other genera. In Nicklesia it is followed by a stage with a
flat venter, and this is then followed by the development of lateral costz
that cross the venter without tubercles or channels, or the latter may be
developed directly from the previous stage.
Subpulchellia has similar stages followed by a channeled venter due to
the development of two slight ridges.
Pulchellia develops lateral coste that cross the venter, but these are
concave on the venter and have lateral tubercular crests in place of the
ridges of Subpulchellia. The intercostal furrows also cross the venter, but
are usually convex on the venter between the costae. The tubercles have
been universally but erroneously spoken of as keels. They are really not
“The author failed to describe or cite any species belonging to Psilopulchellia.—T. W. S.
PULCHELLIID®. 157
continuous at any stage and can not even be accurately described as ridges.
The term carina or keel should be confined entirely to the continuous
azygous ventral elevation. The term bicarinate is confusing and might be
especially troublesome if occasion should arise to describe a form having
a really double or split keel. A further modification of the development
takes place when a keel arises upon the smooth rounded venter of the
earlier stages as in Psilofissotia. This form is apparently transitional to
true Tissotidee, but these affinities disappear upon comparing the ontogeny
with that of Tissotiidse, and especially when the relations of these to the
flat ventered and keeled and channeled forms of Pseudotissotia are recog-
nized. The sutures of Psilotissotia are also decidedly Pulchellian and there
are also transitional forms connecting it with Psilopulchellia. Lopholobites,
so far as known, appears to be adequately accounted for as a retrogressive
modification of Psilotissotia or some of the smooth forms with which it
agrees in external characters. This suggestion requires, of course, to be
tested by the comparative study of its development and that of the similar
forms of this family.“ The natural arrangement of these genera upon the
basis of their ontogeny seems therefore to be as follows:
Pulchellia
|
Nicklesia Subpulchellia Psilotissotia
———Psilopulchellia Lopholobites
|
Heinzia
It seems obvious from the development of the young of most genera
and the apparently full-grown Subpulchellia, and from the evidence of the
sutures, that this group is closely related to Engonoceratidee. If this be so,
the latter can be explained as a retrogressive form evolved from Subpulchel-
la as its most probable Neocomian ancestor. The supposed relations of
some of the genera to Stoliczkaia are discussed under the head of Pulchellia.
The parallelism between some of these forms of Pulchellia and the Hoplitidee
is so close that it requires the evidence of their younger stages for their
separation. It is closer than between this genus and any one of the Heinz-
idee, because of the presence of the line of double elongated tubercles in
the latter.
«The Pulchelliidze were not mentioned in my Cephalopod chapter in Zittel’s Text-book, owing to
the accidental omission in copying of a page of the manuscript.
138 PSEUDOCERATITES OF THE CRETACEOUS.
NICKLESIA n. gen. Hyatt.
This genus has a prolonged smooth stage, followed by a costated stage,
in which the costz are without tubercles and cross the more or less rounded
convex venter without becoming concave. In some species, as in the type
LY. dumasiana], the venter does not become decidedly flattened at any
stage and the cost are very slightly developed. The following species,
described and fully figured by Nicklés in his Paléontologie du sud-est
de IEspagne,* can be referred to this section of the genus: Nick. moltoi,
levyi, nolani, lapptrenti.
In other species the venter becomes markedly flattened during the
latter part of the smooth stage, and the following species, described by the
same author, are referable to this section: Nick. zeilleri, mallade, bertrandi.
NICKLESIA ALICANTENSIS n. sp. Hyatt.
Pulchellia (Stol.t) pulchella Nickles, 1890, Mém. Soc. géol. France, Paléontologie,
Nos 45) patd. ipl. dietioss lOnaae
This differs from d’Orbigny’s species in having regularly dichotomous,
more or less sigmoidal costae, a wider umbilicus, less compressed form, and
broader venter. :
The following species can also be included under this head: Nick.
karsteni (Uhlig)”’ (pulchellus of Karsten).
NICKLESIA LENTICULATA n. sp. Hyatt.
Pulchellia aft. pulchella Gerhardt, 1897, Neues Jahrb. fiir Min., Geol., und Pal., Beil.-
Bd. XI, p. 154, pl. 3, fig. 9.
D’Orbigny’s species has several short costee between the longer ones,
and the internal sections between the longer costations are smooth, whereas
in both of the above the costee are crowded together and cover the sides of
the shells.
NICKLESIA pipayaNna (d’Orbigny).
Nick. didayana (VOrbigny), another species of this group, has been
often misapplied to species having channels on the venter and lateral
tubercles.
aMém. Soe. géol. France, Paléontologie, No. 4, 1890.
» Wernsdorfer Schichten, Denkschr. K. Akad. Wiss., Wien, Vol. XLVI, 1883.
PULCHELLUD.®. 139
Nickuesia pumastana (d’Orbigny).
Pl. XVII, figs. 6-8.
Ammonites dumasianus VOrbigny, 1842, Voyage dans l Amérique méridionale, Vol.
III, p. 69, pl. 17.
This species is fully figured by d’Orbigny, and easily recognizable in
case of large specimens. The French specimens that usually bear this name
have been retained here with a question mark. The three examples that
are in the Museum of Comparative Zoology are much smaller than the
figures of the South American species, but are otherwise identical, and there
are no young forms of the latter for comparison. The young specimen
figured shows the development of the generic cost directly from a form
with a rounded venter, without the intervention of a flat or concave venter.
Locality: Colombia, South America; Escragnolles, France.
Age: Neocomian.
SUBPULCHELLIA n. gen. Hyatt.
This becomes a distinct generic group, consistently with the principles
advocated in this and other papers, because it represents a distinct grade in
the evolution of the Pulchelliidee. Its permanent adult characteristics cor-
respond to those of the transient condition of the neanic stage in the young
of Pulchellia. Subpulchellia oehlerti (Nickles) has a smooth involute shell,
with a concave ventral area bordered by two ridges. The venter on casts
is usually flat and has no definite ridges.
The genus includes also Subp. fouquei (Nickles), and Subp. sauvageaui
(Nickles. )
Subp. sauvageaui (Sayn) has lobes and saddles quite different from the
Spanish form as figured by Nicklés, but whether it or Nicklés’s species
is identical with Hermite’s it is not possible to state. Hermite’s original
description and figure give no sutures. The shell as described in correction
of the figure“ has slight costations, present also in Sayn’s, as described but
not as figured, and not mentioned at all in Nicklés’s description. The
sutures of Nicklés’s specimens, one from near Constantine, Africa, and the
other from Spain, are similar, but entirely distinct from those of Sayn’s
figure. Until the suture of Hermite’s original or of a specimen from the
«Hermite, Etudes géol. sur les Iles Baléares, Vol. I, 1879, p. 315, pl. 4, figs. 4, 5.
140 PSEUDOCERATITES OF THE CRETACEOUS. :
same locality has been investigated, it can not be stated whether Sayn’s or
Nicklés’s species are really the same as Hermite’s. In these smooth forms
the shells can not be relied on to show specific differences.
SUBPULCHELLIA CASTELLANENSIS n. sp. Hyatt.
Pl. XVII, figs. 1-5.
The two specimens in the Museum of Comparative Zoology here
described as the types of the genus and species are both smooth, compressed,
highly involute shells similar to sawvageawi and others in aspect, but with
denticulations on the auxiliary saddles not found in those species. The
largest specimen is a cast 28 mm. in whole diameter, probably when
complete about 40 mm. The inner edge of the living chamber shows on
one side and this was about one-half of a volution in length. The suture
figured was taken from the oldest stage of this specimen. The venter in
this cast is plano-convex, and there are ridges on the ventro-lateral angles,
but these are ridges because the lateral zones are faintly concave,
consequently they are ridge-like toward the lateral aspects and not on the
venter. The center of the venter has a raised line or pseudo-keel such as
is figured by Sayn in his Pul. sauwvageaui, and is not uncommon in species
of Placenticeras. When the shell is present the venter is slightly concave
and it has the usual ventro-lateral ridges. The specimen figured (PI. XVII,
figs. 1-4) is somewhat younger, but shows a partially completed living
chamber a little longer than one-half of a volution.
Locality: Castellanes, France.
Age: Neocomian.
PULCHELLIA Uhlig.
Uhlig designated three groups when he described this genus, the
so-called bicarinated or true Pulchellia, the group with coste crossing
the venter, equal to my Nicklesia, and those with a keel on the venter,
the equivalents of the cenus Psilotissotia. Nicklés recapitulates these facts
and the observations of Douvillé, and joins him in referring the first group to
Pulchellia, and also in thinking it possible that P. pulchella and some others
may be referred to Stoliczkaia. Nickles, however, retains these forms under
the general name Pulchellia, and places the other generic names in brackets.
PULCHELLIIDZ. 141
He has also traced some differeuces between the sutures of the different
groups, but these are of such a nature that one does not get clear impressions
from drawings, although those of Nicklés are remarkable for their excellence
and full of instructive details. I unfortunately can not agree with these
gentlemen with regard to Stoliczkaia.
Neumayr® states ‘‘sehe ich mich genéthigt, eine Gattung fiir eine
merkwiirdige kleine Gruppe von Ammoneen aufzustellen, niimlich, fiir die
eigentiimlichen Formen der indischen Kreide, welche Stoliezka * * *
beschrieben und mit den Hiillstatter Arcesten verglichen hat.” He then
goes on to establish new names for the two Indian species considered by
him to be distinct from Ammonites dispar @Orbigny, and the first of these,
Stoliczkaia tetragona Neumayr or Amm. dispar Stoliezka,’ thus becomes the
type of this genus. D’Orbigny’s figure and description of Amm. dispar
shows a compressed involute shell with a volution in section like that of.
Nicklesia pulchella (VOrbigny), but the costae are narrow, and although
they cross the venter they are quite distinct from those of this family.
D’Orbigny’s species is an old shell of some other group, but is related
neither to Pulchellia nor Stoliczkaia.
Stol. tetragona has a quadragonal volution in section when full grown,
venter depressed and slightly convex, sides same, umbilical zone abrupt and
narrow. Ribs very prominent and sharp, reaching across the venter and
side and having alternating shorter costze across the venter. Only one row
of tubercles along the ventro-lateral angles in the young until in the neanic
stage. These disappear in the adult. This is precisely the form and gen-
eral aspect of some of the Mantelliceratide. For example, Amm.
mantelli is either a member of this genus or a very similar parallel form.
But none of these have costae or ornaments or channels like those of
Mantelliceratidee. Probably also the young are more or less distinet in
development.
Whether this last be true or not, the agreements of the adult sutures
are not close enough to place such widely different structured shells as
Stol. tetragona and Pulchellia pulchella in the same group, especially when
there is close agreement between the latter and the younger stages of the
typical P. compressissima and the suture lines are also similar.
aZeitschr. Deutsch. geol. Gesell., Vol. XX VII, 1875, p. 931.
b Foss. Ceph. Cret. Southern India, pl. 45, f. 2.
142 PSEUDOCERATITES OF THE CRETACEOUS.
The keeled smooth forms were also referred by Douvillé and Nicklés
and by myself in Cephalopods of Zittel’s Text-book under the name of
Psilotissotia to Tissotidee, but I am now satisfied that this is an erroneous
view of their true affinities, and they are here retained in the Pulchelliide.
PULCHELLIA NICKLESI n. sp. Hyatt,
Pulchalia compressissima Nickles, 1890, Mém. Soc. géol. France, Paléontologie,
No. 4, p. 8, pls. 1 and 3.
This species is now, thanks to the drawings and descriptions of Nickles,
sufficiently well known so far as the neanic and ephebic stages are con-
cerned, and it is not venturesome to say that in the still younger stages
the venter must have been rounded and smooth like that of the group here
named Psilopulchellia. The true P. compressissima VOrbigny is a much
thinner shell, with broader costze and narrower venter, the costal folds on
the venter narrower and less deeply channeled. Doubtless the young are
correspondingly distinct. The umbilicus is also narrower. Pulchellia schlum-
bergeri Nicklés, Mém. Soe. géol. France, Paléontologie, No. 4, p. 38, pls. 7.
and 8; Pul. columbiana (compressissima Gerhardt), also figured by d’Orbigny
as the young of his Amm. galeatus in the Voyage dans ’Amérique mérid-
ionale, Pul. selecta, and Pul. hettneri also belong to this genus.
Age: Barremian.
There are two species described from Djebel-Ouach by Sayn, Pul.
changarniert’: Say and Pul. kiliant. n. sp. (Pul. (Heinzia) ouachensis, Sayn,"
pars). This last is distinet from Heinzia ouachensis Sayn in not having an
inner line of tubercles and in its narrower ventral channels as well as in its
sutures as described by Sayn.
PULCHELLIA COMPRESSISSIMA (d’Orbigny).
Pl. XVI, figs. 9-12.
Ammonites compressissimus VOrbigny, 1840, Terr. Crétacé, pl. 61.
This species is very peculiar and altogether distinct from the forms
usually placed under the same name by authors generally. D’Orbigny’s
figure is very similar to a specimen of the Krantz collection from Esera-
enolles, the same locality as the shell figured by d’Orbigny. The form of
this cast is quite as much compressed and involute, the coste are present
«Ann. Soe. d’ Agriculture de Lyon, 6th series, Vol. III, 1890, p. 155, pl. 2, fig. 15, not fig. 14.
PULCHELLIID. 143
only on the outer half of the sides, the spaces between are narrow sulcations
that cross the venter. The costee cross the venter with undiminished
breadth and are channeled, but this channel is so shallow that I at first
thought this must be the young of another species with very broad coste,
Amm. catillus VOrbigny. The specimen described is just a little older than
the shell figured as compressissimus by @Orbigny and ribs begin suddenly to
bend forward on the last part of the outer volution. Amm. catillus VOrbigny
may also belong to this genus, but the characters of the young, which alone
can determine this question, are not known.
Locality: Escragnolles, France.
Age: Neocomian.
PSILOTISSOTIA Hyatt.
This genus was unluckily considered by me when mentioned for the
first time“ as a member of the Tissotiidee. In this I was not led by the
opinions of Douvillé and Nicklés, but by what I then considered to be its
true affinities. It has become obvious in studying Paratissotia, which
approaches it nearest in form and in agreement of the development, that
this is not a natural association. Nicklés’s plates also show that the sutures
are similar to those of true Pulchelliidee. They are involute forms, smooth,
and compressed in the earlier stages and having at this time or all through
the neanic stage a smooth keel that may in older stages become tubercu-
lated. Costa may be represented by fine folds as in Psil. mariole Nickles,
until a late age, but when they do appear they are heavy, fold-like, and
sigmoidal. In this species also a median lateral line of nodes appears. If
their real affinities are with this family, as they certainly appear to be now,
they can be accounted for as direct derivations of Psilopulchellia which has
evolved a keel. The intermediate aspect of species like Pul. defforgesi and
haugi indicates that the shell did not have a flat ventral area at any stage,
but was the direct outcome of the evolution of Psilopulchellia.
This includes besides the type, Psi. chalmasi (Nickles), the following
species: Psil. mariola, detiorgesi, reigi, haugi, Nickles; Pul. defforgesi Nickles
is described by him as having simply a sharp venter, but its aftinity with
mariolae would bring it into the group and the sharp venter may be
merely due to the age of the example figured.
« Zittel’s Text-book, p. 590.
144 PSEUDOCERATITES OF THE CRETACEOUS.
LOPHOLOBITES Hyatt.
LopHo.osires coTrEautl (Nicklés).
Neolobites ? cotteaui Nicklés, 1890, Mém. Soc. géol. France, Paleontologie, No. 4,
p. 54, figs. 36, 37; pl. 5, fig. 9.
Lopholobites cotteaui Hyatt, 1900, Ceph. Zittel’s Text-book Pal., p. 590.
This is a small, very involute, compressed, smooth form, with minute
umbilicus and subacute venter. The external characteristics and sutures
indicate this to be a retrogressive but more involute shell, allied to such
species as Psilotissotia haugi, figured on the same plate by Nicklés. The
sutures are entirely distinct from those of Neolobites, especially in the bifid
character of the first lateral saddles and the greater differentiation of the
inner saddles and lobes, which are more distinct from those of the outer
part of the same sutures than in Neolobites. All of these discrepancies
can be accounted for on the supposition that this is a retrograde form of
Pulchellia. This also accounts for its small size when nearly outgrown, as
in this specimen. Nicklés recognized the great differences between this
shell and Neolobites, but hesitated to describe it as a different genus because
of the great difference in its size. This fear was unfounded, since Neolobites
could not have had a similar set of sutures at any age.
Age: Barremian.
KNEMICERATID-.
The external aspect of the species of this group places them apparently
close to the Buchiceratidee, but the sutures and the absence of a keel at all
stages separate them widely. The first lateral saddles exhibit tendencies
to division into several distinct branches, as in the Engonoceratide, and
the outlines of the other saddles and lobes also are similar. ‘The division
of the first lateral saddles is not carried so far as it is in Engonoceratide.
The principal first lateral resulting from the secondary division of the
primitive first lateral is consequently a broad solid saddle instead of the
narrow first lateral of that family.
Unluckily, the dorsal sutures were in no case exposed, and the
conditions of fossilization in every specimen made excavation impracticable.
The forms, both by their ornamentation and general development,
are apparently more specialized and more complex than those of the
Engonoceratidz, and although the young was seen in only one example in
a section the appearances were the same as in sections of species of the
KNEMICERATID.®. 145
Engonoceratidz. It has been therefore assumed that they had a similar
stage in which the venter was concave and had continuous ridges on the
ventro-lateral angles.
KNEMICERAS Bohm.‘
There are but two lines of nodes on the sides and straight broad costee,
bifurcating between them. The venter is broad and coneave, the coste
and nodes are opposite, and the venter is often transversely ridged between
the nodes. The ventral lobes have the same shape as in Buchiceras and
Roemeroceras and have similar truncated siphonal saddles. The ornamenta-
tion and form resemble these genera, but there is no keel at any age and
the development is quite distinct. The young are not compressed as in
Buchiceras, and the ventral zone is coneave in an early neanic substage and
remains concave throughout life. This shows similarity to Hngonoceras and
Placenticeras. The lateral lobes and saddles are similar to those of Hngono-
ceras, but the inner laterals are fewer in number and the first lateral saddles
are more complicated. The divisions of the first may be counted as four
or even five lateral saddles derived from a primitive first lateral. Until
some one ontogeny is studied the correct enumeration can not be given.
The young were seen in section. The rounded venter of the nepionic
stage is succeeded in the neanic stage by a flat-ventered volution with quad-
ragonal outline, and the concave venter appears in the earliest part of the
ephebic stage. At this time the venter is very broad, the sides flat and
obviously costated and tuberculated on the umbilical shoulders. Whether
there were tubercles on the edges of the venter was not determinable.
At an early neanic substage the umbilicus was open, the venter flat
and broad, but narrower than the dorsal diameter through the umbilical
shoulders, the lateral zones flat and convergent, the umbilical zones well
developed. These characters and the broad costee and nodes of the later
stages and the venter are similar to those of Pulchelliidee, but the division
of the first lateral saddles in full-grown specimens and other sutural
characters are dissimilar. The species discovered in the Cenomanian of
Portugal appears to indicate that the real age of the fossils found at Mount
Lebanon is Cenomanian, although, as may be seen by the context, I have
doubts whether any of the latter belong to the fauna of the rocks in which
they have been found.
a Zeitschr. Deutsch. geol. Gesell., Vol. L, 1898, p. 200. ‘
10
MON XLIV—03
146 PSEUDOCERATITES OF THE CRETACEOUS.
IKXNEMICERAS SYRIACUM (von Buch).
Pl. XVI, figs. 4-8.
Amm. syriacus yon Buch, Abhandl. K. Akad. Wiss. zu Berlin, 1848, pl. 6.
Knemiceras syriacum Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, p. 200.
Von Buch’s figures of this species on his pl. 6 are excellent in all
characters, but his. suture line on pl. 7 is either erroneous or belongs to
another form.
One gerontic specimen is about 55 mm. in whole diameter, with living
chamber nearly one-half of a volution in length. A smaller specimen, 45
mm. in diameter, has also reached into an extreme gerontic substage and
has living chamber of same length. Von Buch’s specimen, according to
his figures, was also in gerontic stage, but evidently somewhat larger,
perhaps 70 mm., or thereabouts, when living chamber was present.
This stage is indicated in one specimen as in von Buch’s figure by the
approximation of septa in pairs as if the individual were only temporarily
affected by weakness and then resumed the usual rate of increase. In one
specimen the last sutures are irregularly spaced. The last three next to
the living chamber are approximate. A slightly greater interval occurs
between these, and there is a pair closely approximated, and apicad of this
is a broader chamber and again a pair of approximated sutures. Apicad of
this last pair there is a chamber broad on the venter but so narrow near the
lines of involution that the sutures are crowded together on the umbilical
shoulder. Apicad of this is the ephebic stage, with all sutures regularly
spaced. The gerontic sutures are not always so irregular, and there may
be as many as eight sutures showing more or less inequality in spacing,
ending with a series gradually becoming closer and eventually overlapping.
The whole duration of the gerontic stage, including the living chamber,
consists of about three-fourths of a volution. The lobes and saddles become
shorter and the outlines simpler in this stage. ‘Temporary approximation
of sutures occurs often in the growth of these shells, and it is not always a
sign that the gerontic stage has been reached, but when it is continued for
some time, as in von Buch’s figure, and after a period of prolonged regu-
larity in the width of the living chambers, it is obviously due to senility.
There are no signs of a row of tubercles on the median aspect of the sides,
and there are obviously only two rows of nodes with heavy fold-like bifurcated
costae between.
KNEMICERATID®. 147
The nodes continue to increase in length and size throughout life until
in the latter half of the gerontic living chamber, when they show a decided
and rapid decrease on the venter but persistently increase on the umbilical
shoulders until near the end of this chamber. The living chamber was
incomplete on the venter in all of these specimens, although in several it
was complete near the umbilicus and somewhat over one-fourth of a volution
in length.
The first lateral saddles are bifid, having two broad arms, and both of
these are again faintly bifurcated, these subdivisions being minutely
denticulated on the edges in perfectly unworn sutures, which can be found
best by removing encrusting ostreans. In some specimens the second
lateral saddle does not split up completely trom the first, and instead of
three principal lateral saddles there are but two, as shown in PI. XVI, fig. 5.
In others the division is complete, as it probably is in the later stage of the
specimen shown in Pl. XVI, fig. 8. No specimen so far seen carries out
the complete division of the remaining first lateral, although in some the
median marginal lobe is quite long. It is a curious fact that all of these
specimens—eleven in number and collected from five different sources—
should have encrusting bryozoa and ostreans on the exterior of the cast and
all more or less worn on all other parts of the surface. The lobes and
saddles nowhere exhibit, and it is not likely that this species ever exhibited,
the peculiar lobes and saddles figured by von Buch on his pl. 7. The
entire suture seems to be incorrect for this species, whereas those given
in pl. 6 are right so far as they go, although taken from the usual
worn surfaces, of casts. Béhm’s figure, quoted below, is accurate, but
belongs to an older stage than that figured in this work. The
second and sixth lateral saddles are bifid, the seventh and eighth broad,
flattened, and entire. There are marks upon unworn sutures indicating the
presence of slight denticles on the edges of the principal saddles, but no
such divisions and prominent marginals as in von Buch’s figure, pl. 7. The
ventral lobe has two arms as in Hngonoceras ; the dividing siphonal saddle is
apparently flat, but when clearly defined it has a diminishing base divided
by a minute siphonal lobe. Faint denticulations are present on both this
saddle and the sides of the arms of the ventral lobe. The lateral lobes are
club shaped, denticulated on the top, but entire on the sides near their
base between the phyllitorm bases of the saddle. There are irregular trifid
148 PSEUDOCERATITES OF THE CRETACEOUS.
outlines such as appear in Bohm’s figure,* but there are also regular trifid
bases to the first lateral saddles. The former arise from the irregular
growth of the marginal saddles of the first or outer (originally bifid) arm
of the first lateral saddle, making sometimes a simple triple division, and
sometimes this outer arm itself becomes trifid, equally or more or less
unequally, as in Béhm’s figure. The variation of the sutures is very
considerable in this species, but there seems to be, so far as my material
reaches, no sufficient grounds for the separation of specimens having’ trifid
first lateral saddles from those having this part bifid. In fact one
specimen shows early in the ephebic stage a bifid first lateral on one side
and a trifid saddle on the other side of the venter, i. e., the two arms
of the first lateral on one side are regularly bifid and on the other the
imner arm is trifid and the outer arm bifid. Occasionally this outer arm
may have four marginals. In one specimen the inner arm is bifid and the
outer arm has three minute marginals. In one specimen again (PI. XVI,
fig. 5) there are three arms, each regularly subdivided by a median
marginal lobe. This saddle can perhaps be best described in general
terms as having three arms derived from an original bifid form and
usually preserving a record of this original form in the shortness of the
outer marginal lobe as compared with the second marginal and. also in
the usually bifid outline of the base of the third or innermost arm. Often,
as in Pl. XVI, fig. 8, the inner arm is sufficiently separated to be counted
as a second lateral saddle.
The specimen described by Hamlin in Syrian Fossils’ is fine only on
one side and the supposed shell ‘the thin test almost entire” does not
exist. Hamlin was misled by the smooth surface and the presence of a
thin brown layer. That this is not the shell is shown by the sutures,
which are somewhat worn, not showing the denticulations plainly. The
living chamber is obviously nearly complete and is a trifle less than
one-half of a volution in length. I have examined twenty-two specimens
of this species and not a single one had even fragments of the shell
preserved and many were incrusted with ostreans and bryozoa. There is
no positive proof that these ammonites were living members of the fauna
in which they were found, but there are obvious reasons in their aspect
@ Ueber Amm. pedernalis: Zeitsch. Deutsch. geol. Gesell., Vol. L, 1898, p. 199.
bMem. Mus. Comp. Zool., Vol. X, No. 3, 1884, p. 11.
KNEMICERATID®. 149
and in the presence of these incrusting growths on the casts for consid-
ering them as having been fossil casts when the incrusting animals grew
upon them.
Locality: Mount Lebanon, Syria.
Age: Cenomanian.
KNEMICERAS COMPRESSUM n. sp. Hyatt.
Pl. XVI, figs. 9, 10, 15-18.
Ammonites vibrayeanus Hamlin, 1884+, Mem. Mus. Comp. Zool., Vol. X, No. 3, p. 12.
The typical form of this species is separable from the variety
subcompressum in full-grown specimens by the greater compression of the
volutions, narrower venter, and less development of the nodes on the
umbilical shoulders. The proportionate increase by growth of the ventro-
dorsal diameters is also greater with relation to the transverse than in the
stouter variety described below, and in all these respects it differs still more
from Annem. syriacum. The shell, however, until 45 to 50 mm. in diameter
is not distinguishable from the shell of that species. As stated by Fraas and
Hamlin, the sutures in the worn casts are similar to syriacum, but in a large
specimen of the same size as the type of this species (Pl: XVI, fig. 15) in
the Museum of Comparative Zoology these are less worn than usual and
full grown. These sutures (PI. XV1, figs. 17, 18) show the large ventral
lobes, which occupy nearly the entire breadth of the venter instead of only
the central part, as in the stouter variety and in syriacum. The lateral
saddles and lobes are very long and narrow and the bases of the saddles
swollen, rounded, and phylliform, resembling those of Sphenodiscus. The
apical ends of the saddles are also similarly shaped, broad, denticulated,
and cutting deeply into the saddles. In the gerontic stage the lobes and
saddles become shorter again, as in the younger stages, and more like those
of syriacum. The most pertect cast (PI. XVI, figs. 15, 16) is 70 mm. in
‘diameter, without living chamber, the outer volution 88 mm., the umbilicus
10 mm., and same volution opposite 22 mm., the thickness of the last being
13 mm. between costee.
The largest specimen is from Beirut, No. 10902G in the collection of
Columbia University. This has no living chamber, and the actual
diameter is 85 mm., estimated diameter about 90 mm. Diameter when
living chamber was present could not have been Jess than 130 mm.
150 PSEUDOCERATITES OF THE CRETACEOUS. ,
Sutures are considerably worn, except in one place at diameter of 75 mm.,
the volution being 23 mm. ventro-dorsal diameter. These were similar to -
those of the typical specimens, except the first lateral saddles, which were
narrower and distinctly bifid; the innermost inflections were not seen.
The nodes were present on the umbilical shoulders, but apparently
disappear on the last half of the outer volution, but this could not be
proved on account of the state of this fossil.
The venter remained concave to the end. The ventral tubercles
became, however, much finer and more closely set than in the ephebie
stage, and IT should think more perfect specimens might show the
correlative disappeazance or obsolescence of the costations. I doubt if the
coste are ever so broad in this species as in syriacum. The state of these
fossil casts tends to confirm the opinion that they were not living members
of the fauna with which they were found.
Out of the eight casts in the Museum of Comparative Zoology only
three were suitable for observation, and all of the three more or less
imperfect, and there was not even the minutest piece of a shell on any of
them. The same is also true of the large specimen from the collection of
Columbia University.
KNEMICERAS COMPRESSUM var. SUBCOMPRESSUM Hyatt.
Pl. XVI, figs. 11-14, 19. ‘
Amm. syriacus (pars) von Buch, Abhandl. K. Acad. Wiss. zu Berlin, 1848 (not
figured).
Amm. syriacus (pars) Conrad, Lynch’s Exp. Dead Sea and Jordan, 1852, pl. 14, fig.
74, two upper figures (not fig. 6).
This variety has heretofore been confounded with nem. syriacum,
from which it is, howeyer, easily separated. The form even in extreme age
is more compressed, the nodes on the umbilical shoulders are not so promi-
nent, and the venter and transverse diameters do not broaden out in the
later ephebic and gerontic substages, as in that species; the nodes also on
the edges of the venter are longer and narrower than in that species. The
sutures are very similar in these two forms.
A specimen from Mukhtara, Syria, in the American Museum of
Natural History, New York, reaches 97 mm. diameter without living cham-
ber, and shows that the shell sometimes reaches a larger size than 115 mm.
in diameter.
KNEMICERATID.®. 151
A specimen in the Museum of Comparative Zoology is 50 mm. in
. diameter. This retained its flatter sides and proportionally broad venter to
the end of the last volution. The living chamber is incomplete and
somewhat less than half of a volution in length. A specimen from Abeih,
Mount Lebanon, in the Museum of Comparative Zoology, 53 mm. in diam-
eter, has a living chamber obviously very nearly complete and somewhat
less than half a volution in length. This is therefore approximately the
length of this part. One of the specimens in the Krantz collection in the
Museum of Comparative Zoology shows thick shell on venter where it has
been covered and protected by outer volution. Outside of this the cast is
worn more or less, and there are absolutely no remnants of shell under the
encrusting ostreans that occur on the exposed parts. The condition, in
other words, proves that this and probably other fossils mentioned above
were not living members of the Syrian fauna as heretofore described, but
came from some earlier epoch and were already in the condition of fossil
casts when the incrusting ostreans grew upon them.
Locality: Gilead Mountains east of Jordan, Mount Lebanon, Syria.
Age: Cenomanian
IXKNEMICERAS ATTENUATUM (Hyatt).
Pl. XVU, figs. 13-15.
Buchiceras attenuatum Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p. 372.
Glottoceras attenuatum Hyatt, ibid, note.
The sutures agree quite closely with those of AKnemiceras compressum,
but the alternating tubercles on the edges of the venter and the form of
this part are essentially Engonoceran.
The original specimen is 65 mm. in diameter; it is a cast without any
vestiges of the shell. The ventral lobe is deep and narrow and like that of
Knemiceras The first lateral saddle is also Knemiceran in outline. It is
unequally divided into three parts. The outer arm is trifid, but with such
slight marginals that they are merely sinuosities. The central part is a
minute saddle, and the inner has a trifid base. The second lateral is
phylliform and so faintly bifid that I was not sure of the fact. All the
remaining saddles are subphylliform, with broad bases and symmetrically
bifid, except the seventh and eighth, the last on the line of involution.
These are entire. he first to the sixth lobes are simple and denticulated;
the seventh and eighth are entire.
152 PSEUDOCERATITES OF THE CRETACEOUS
This species was named erroneously Glottoceras in a note quoted above
and accidentally left uncorrected in the proof.
The great regularity of the outlines of the bifid saddles and the small
dividing marginal lobes are probably characteristic, as well as the fineness
and number of the tubercles of the outer lines and the presence of a third
line beginning, apparently, on the latter part of the outer volution.
Locality: Celendin, Peru.
Age: Cenomanian?
KKNEMICERAS GABBI n. sp. Hyatt.
Pl. XVIU, figs. 1-3.
Ammonites attenuatus Gabb, 1877, Jour. Acad. Nat. Sci. Philadelphia, 2d series, Vol.
VIII. p. 264, pl. 36, fig. 1 a and 3.
The originals of Gabb’s figures have not been found in the collections
ot the Academy of Sciences of Philadelphia and I could not obtain them
for comparison, but the suture line figured by Gabb is distinct from that
given on Pl. XVII of this work, and Gabb’s form is much stouter at the
same age, lias larger nodes and a broader venter. The old age with a
rounded broad venter is probably not particularly distinctive, although it
may perhaps be that this change never occurs to such excess in true
attenuatum as it does in gabbi. :
Locality: Quebrada de Huari, Peru.
Age: Cenomanian?
IKNEMICERAS UHLIGI (Choffat).
Placenticeras me Choffat, 1898, Faune Crét. du Portugal, Vol. I, 2d Bah pp. 4
and 77, pl. 2, figs. 8-5; pl. 4, fig. 2; and pl. 22, figs. 4446.
This is a compressed species similar to An. compressum, but differing in
the sutures. The saddles are very broad and have flat bases with more
denticulations. The lobes are more like those of compressum, but the inner
ones are quite different. The marginal divisions are less complete than in
COMPVESSUM.
Locality: Portugal.
Age: Lower Bellasian (Cenomanian.)
DESCRIPTIONS OF SPECIES. 153
; ENGONOCERATID&.
Shells apt to be involute. The venter is concave and is occupied for
its entire breadth by a smooth zone. The sutures are variable in the different
genera and approximate in some forms to those of Sphenodiscus. There is
a similar tendency in most of the species to have broad saddles with
phylliform bases, which are either entire or bifid, while the lobes have
narrow bases and are more or less expanded apicad and apt to have trifid
terminations. The simplicity and shortness of the saddles and lobes is
correlated with the tendency to produce a much larger number ot
inflections and great variability in the outlines in the same species and
sometimes even on different sides of the same specimen. The ventral lobes
‘are short, spreading apically, and have usually pointed short and entire
siphonal saddles.
PROTENGONOCERAS Hyatt.
The ephebic form is compressed and involute, as in Hngonoceras and
Metengonoceras of the same subfamily group, and it is also similar to the
neanic stages of Engonoceras, Sphenodiscus, and Placenticeras.
The shell is smooth, except in the gerontic stage, where folds appear.
The venter is moderately broad and decidedly coneave, bordered by sharp,
smooth ridges. These are exactly the external characters of the young
during neanic stages of the species of the different genera mentioned.
The sutures have the same ventral lobes as in Engonoceras and
Metengonoceras, and similar lateral sutures, but the saddles are very broad
and short and the lobes have fewer marginals.
Type, Prot. gabbi (Bohn), Whitney collection, in Museum of Com-
parative Zoology.
The septa follow internally the curvatures of the sutures, concave
along the mesal plane and convex only on the areas on each side of the
zone of involution.
PROTENGONOCERAS GABBI (Bohm).
Pl. XVII, figs. 16-20.
Ammonites pedernalis Gabb, 1869, Pal. California, Voi. H, pl. 35, figs. 1, 1a.
Engonoceras gabbi Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, p. 197.
A cast of one-half of a volution in Museum of Comparative Zoology
from Professor Whitney shows ephebic stage. The whole diameter, partly
154 PSEUDOCERATITES OF THE CRETACEOUS. .
estimated, is 69.5 mm., the outer portion of this volution, partly estimated,
is 42.5 mm., the umbilicus is 5 mm. and the opposite part of same volution is
22 mm. The shell is present on the venter but not on the line of involu-
tion. Greatest transverse diameter of outer volution is 25 mm., the inner
part is 11 mm., both through the umbilical shoulders, shell on one side and
not on the other side. Probably shell would have made the difference of
5 mm. in each ease.
This is a compressed shell, closely similar in aspect to E’ngonoceras
uddeni and the ephebic smooth stage of Protengonoceras ? emarginatum, but
the involution is greater; the costations in this stage are fainter, but can be
plainly enough seen both on cast and on the shell in a cross light. They
are less than in Gabb’s figure, but the form of venter and aspect of shell,
including amount of involution, shows that we are dealing with Gabb’s
species. There are also no tubercles on the umbilical shoulders. The first
large fold is partly present on the broken edge of the outer volution in
the small fragment figured, showing the beginning of the gerontie stage.
The venter is decidedly concave with slight ridges on either side. This
form of venter is found in the neanic stage and the whorls, although
stouter, are similarly compressed when the whole diameter is only 13 mm.
At diameter of +4 mm. this venter, although almost as broad as the trans-
verse diameter, is already like that of the adult, but may be a little flatter.
Other details could not be seen. It is obvious that the young acquire
the concavity and sharp lateral ridges of the venter in an early neanic
substage at a time when the volution becomes flattened on the lateral
zones. The form is then obyiously like some stouter and less involute
forms of this genus not yet discovered.
The sutures are very slightly flexed apicad; the saddles and lobes
closely similar to those of Metengonoceras.
The venter is slightly asymmetrical; the first pair of saddles on the
right are divided by a very slight marginal lobe. There are nine saddles
and eight lobes on the right side, the seventh saddle alone being bifid.
The marginal lobe dividing this saddle appears on the earliest suture of
this volution. Lobes on the left side of a more advanced stage show that
this simplicity is due to age.
A larger specimen, same locality, in the gerontic stage, is 108.5 mm. in
diameter and has the shell preserved. Outer part is 57.5 mm., umbilicus
ENGONOCERATID Jb. 155
7.5 mm., and opposite side same volution 46.5 mm., no shell present. The
ereatest transverse diameter of the volution is 30 mm., and of thesmaller
part opposite is 22 mm.
The shell is marked by bands of growth and fold-lke obscure coste
which appear in the gerontic stage. These terminate at the umbilical
shoulders, and along the centran surface of the lateral aspect have very
broad swellings and then subside into the flat general surface toward the
periphery. The venter is slightly broader than in the ephebie stage above
described and the volution stouter, owing to the development of lateral
swellings and the slight decrease in the involution due to old age. The
umbilical shoulders and the umbilical zones are abrupt instead of being .
rounded and sloping as in the adults. The living chamber is complete
near the line of involution and is about one-half of a volution long
internally and apparently about the same externally when restored. The
concavity of the venter is maintained for one-half of the length of the
living chamber. Beyond this it could not be followed, but there are some
indications of the possible rounding of the venter in extreme age.
The sutures are quite distinct from those of the ephebic stage in the
specimen above described. ‘There were eight saddles and seven lobes to the
umbilical shoulders, remainder on the umbilical zones being concealed.
The interesting fact, however, can be noted that in this gerontic stage new
saddles and lobes were not added as the sides broadened. The increase of
the sides was met by the broadening out of the saddles. The first laterals
were very broad, the second and third had not changed much, but begin-
ning with the fourth they became irregularly broader toward the umbilicus,
and the seventh was 6 mm. in breadth, whereas the sixth lobe was only
about 1 mm. long. The lobes remained about the same as in the adult
Stage.
The form of the volutions, smooth concave venter, slightly costated
sides, with large folds only in gerontic¢ stage, and primitive sutures all show
that this is a species like the similar stages in the development of tuberculated
forms in Metengonoceras and also similar to the young of Placenticeras. It
is, however, a deeply involute shell and is not therefore by any means the
most primitive form of its own subseries. It indicates the existence of a
distinct subseries having similar smooth concave venters and less involute
or more discoidal shells, which in the gerontic stage become stouter with
156 PSEUDOCERATITES OF THE CRETACEOUS. :
zibbous sides and have also comparatively flattened or rounded and much
wider venters.
Having been loaned through the kindness of Dr, Pilsbry another speci-
men of this species from the collection of the Academy of Sciences, Phila-
delphia (Pl. XVII, fig. 20), I can state the following additional particulars:
The diameter is about 82 mm., partly estimated. The living chamber is
one-half of a volution in length on the periphery, but is much shorter on
the line of involution, owing to the great apical trend of the aperture. This
has a broad but very slight sinus on either side and apparently no lateral
crests on the sides that could be separated from the rostrum. This last,
however, was broken and could not be decisively determined. The
specimen is in its gerontic stage and upon the inner parts of each side has
four heavy folds which disappear near the venter. The bifidity of the
internal saddles is variable, since in another specimen in the collection ot
the Museum of Comparative Zoology the sixth saddles were bifid.
Locality: Arivechi, Sonora, Mexico.
Age: Fredericksburg group, Comanche series.
PROTENGONOCERAS PLANUM n. sp. Hyatt.
Pl. XVII, figs. 6-9.
This species is described from a fragment which would be ordinarily
insufficient for diagnostic work. The greatest length of this piece is only
22.5 mm., the ventro-dorsal diameter of the volution 14 mm., the greatest
diameter at umbilical shoulders 5.6 mm. Nevertheless, the cast is perfectly
smooth, the sides flat, and the venter, which is only 1 mm. in width, is also
smooth, coneave, and biearinate. These characteristics, especially the
attenuated venter and smooth sides, distinguish it quite sufticiently from the
preceding species to justify specific separation. There are ten saddles, all
narrow, the first symmetrically bifurcated, as in other forms of this genus
and Engonoceras. They are entire and from second to eighth more or less
club shaped, but the ninth is broader and bifid. The tenth and eleventh
are entire, occupying the umbilical zone. The dorsal zone of impression
has six saddles, counting the outermost one above mentioned (Pl. XVII,
fig. 9). There are ten narrow zygous external lobes (PI. XVII, fig. 8) on
the right side. The first is club shaped and entire, the second to the fifth
similar, but faintly trifid) The sixth to the tenth are shorter and decrease
ENGONOCERATID.®. 157
in length to the line of involution and are entire. On the opposite or left
side there are ten saddles and eleven lobes. The tenth saddle is completed,
and there is a small lobe on the line of involution. The first saddle is
narrower and the eighth and ninth saddles broad, and both similar to the
ninth on the right side in being bifid. On both sides the first five lobes
are long, and the same change occurs in the shortness of the sixth and
remaining lobes and saddles. ‘The matrix is similar to that which occurs in
the Colorado formation at Horton’s mill, Dallas County, Tex.
Locality: Vexas.
Age: Stanton suggests Upper Cretaceous from the matrix.
PROTENGONOCERAS ? EMARGINATUM (Cragin).“
Sphenodiscus emarginatus ? Cragin, 1893, Geol. Surv. Texas, Fourth Ann. Rept.,
p. 245.
This species is described as having straight distinct ventral channel at
the diameter of 90 mm. and also as having two rows of feeble tubercles, one
on the umbilical shoulders and the other midway on the lateral aspect.
The bilobed saddles mentioned by Cragin indicate a more complicated
suture line than occurs in Protengonoceras as far as known, but the condition
of the venter indicates that genus.
Not having seen any specimens of the species, I can not say positively
that it is a member of this genus.
Locality: 2 miles south of Pleasant Point, Tex.
Age: Comanche series, Walnut beds.
ENGONOCERAS Neumayr.
Although the descriptions and figures of Engonoceras pierdenale led me
to believe that this species had an acute venter, Bohm” has stated, after
studying the fragmentary originals, that these had truncated concave venters, *
bordered by ventro-lateral ridges or elongated tubercles, and that the species
upon which the genus Exgonoceras was founded, Amm. pierdenalis v. Buch,
closely resembles his Eng stolleyi. The two fragments figured by Bohm do
not show conclusively that this is the fact, but it appears to be safest to
follow him in the effort to give stability to von Buch’s name and Neumayr’s
genus. Von Buch’s and Roemer’s descriptions lead to the belief that the
aSee p. 177, where this species is referred to Engonoceras.—T. W. S.
bUeber Ammonites pedernalis v. Buch: Zeitschr. Deutsch. geol. Gesell., Vol. L, 1898, p. 183.
158 PSEUDOCERATITES OF THE CRETACEOUS.
shell casts they described had acute venters, but this is probably an error.
In studying this group of fossils such a mistake is easily made, owing to the
simplicity of the sutures, the narrowness of the flattened venters, and smooth-
ness and symmetrical aspect of the fossils, although considerably worn and
altered by abrasion.
The presence of three distinct lines of nodes, the flatness and nodose
edges of the venter throughout the earlier and ephebic stages, the broad and
often zigzag outline of the venter in the gerontic stage, caused by the extra
development of the outer line of alternating nodes, enable one to separate the
species of this genus readily from those of Metengonoceras, notwithstanding
the close similarity of the sutures. The young during the neanic stage are
compressed, involute, and smooth, with concave venter and form like Pro-
tengonoceras. Von Buch and Neumayr both describe the principal saddles
of Engonoceras pierdenale as bifid, and this occurs in the species here sup-
posed to represent Hngonoceras, but does not occur, so far as known, in
Metengonoceras. All specimens so far seen have been casts, either entirely
naked or with only the nacreous layer partly preserved.
The attention of collectors is called to the fact that some of the species
bear no convincing marks of having been autochthonous members of the
faunas in which they are habitually found.
This genus differs from Neolobites only in having denticulated lobes, if
the fig
gures of the sutures heretofore given correctly represent their, outlines.
ENGONOCERAS BELVIDERENSE (Cragin).
Pl. XVIII, figs. 4; 5.
Ammonites belviderensis Cragin, 1894, 1895, Am. Geol., Vol. XIV, pl. 1, figs. 3-5;
Vol. XVI, p. 369.
Buchiceras (Sphenodiscus) belviderense Cragin, 1900, Colorado Coll. Studies, Vol.
VII, p. 27.
Through the kindness of Professor Cragin I have seen some specimens
of this species, and one of these has been given in the figure. This alone
was not much crushed, but the sutures could not be made out. . The aspect
is similar to that of Eng. uddeni, but the sides and venter are flatter and
smoother. There are similar nodes on the umbilical shoulders and those on
the edges are alternate; there are nascent folds on the outer part of the
sides. It reaches a larger size than other forms before it begins to acquire
ENGONOCERATID.®. 159
the usual gerontie characters—that is, before the venter becomes convex
and more or less zigzag in outline. The type of Cragin’s species is the
small specimen referred to above. This has sutures with numerous small
saddles closely set on the suture line, and, so far as could be seen, one of
Cragin’s fossils of the same lot with that figured had similar sutures.
Cragin describes this species as having a row of tubercles that may be
developed on the inner ends of the low folds or costs oceupying the outer
half of the sides. There are some very obscure signs of the existence of
such markings in these fossils also. These are doubtful even to the touch
and are not visible to the eye. This may be owing to the condition of the
fossils.
Locality: Belvidere, Kans.
Age: Champion bed and Kiowa shales, probably near base of
Washita Comanche series, Lower Cretaceous.
ENGONOCERAS UDDENI (Cragin).
Pl. XIX, figs. 1-6.
Sphenodiseus helviderensis var. uddeni Cragin, 1900, Colorado Coll. Studies, Vol.
VIII, p. 30, pl. 1, figs. 3, 4.
A fragmentary cast in iron pyrite, No. 23147 U. 8. National Museum,
Pl. XIX, fig. 4,5, shows a few of the last sutures and a portion of the
living chamber. The diameter, partly estimated, is about 82 mm., the
outer volution is 44 mm., the umbilicus 8 mm., the same volution opposite
from line of involution to venter 30 mm., no shell being present. The
form is compressed and highly involute, but slightly stouter than in the
more compressed emarginatum. ‘There is only one line of nodes, those on
the umbilical shoulders. The costa are fine, and like elevated bands of
growth gathered to a focus at these nodes. They are sigmoidal with single
fine lines between the nodes, externally more pronounced folds appearing
in the later gerontic substage, but no nodes are present on this part in this
specimen. The venter is flattened until near the last part of the living
chamber, which is distorted through compression.
The part of the living chamber preserved indicates that it was not less
than half a volution on the umbilical side. The ten lobes and eleven
saddles on both sides are very similar in outline to those of emarginatum.
The seventh and eighth lobes on both sides are bifid.
160 PSEUDOCERATITES OF THE CRETACEOUS.
The ventral and also the first lateral saddle are asymmetrical. These
have the usual form but are rather narrow. The internal parts of the
sutures are deflected orad toward the umbilical shoulders so that they rise
materially, giving them a pecular aspect in this specimen. The lobes are
similar to those of emarginatum, but are narrower and shorter and the saddles
broader and shorter in proportion. The second to the sixth saddles are
entire, the seventh to the ninth bifid, and the tenth saddle is on the line of
involution. The sutures are the same on both sides of this specimen. The
lobes are irregularly bifid.
There is a fragment of a larger size consisting of one-fourth of a
volution with stouter proportions, labeled ‘Locality 1490 U. 8. Geological
Survey, north of Pottsboro, Tex., Upper Comanche (Grayson),” that may
belong to the same species, but the sutures and aspect are distinct enough
to belong to a different species.”
The inner line of large nodes and the median lateral are present, but
no outer line, and there are similar distinct costations.
The venter has a similar outline also, but the specimen being larger
and older, the venter is more rounded.
The sutures are similar, except that the inner arm of the first lateral
saddle is much narrower and entire, the outer arm is distinctly bifid, making
the whole outline approximately trifid, the remaining saddles are longer and
distinctly phylliform as in Sphenodiscus, and the lobes are correspondingly
broader apically as in that genus. hese effects may perhaps be due to
the greater age of the specimen. There is apparently the same number of
lobes and saddles. There are nine saddles visible on the broken end, right
side, and there may be one more, making ten saddles and nine lobes.
A fragment obtained from Dr. F. A. Udden, locality northeast of Little
River station, Rice County, Kans., is the original specimen used by Cragin
and is figured below on. PI. XIX. It is in fine state of preservation, being
fossilized with iron pyrite. The breadth of the side is 53 mm., the greatest
transverse diameter is at about one-third of the breadth from the line of
involution and is 20.5 mm. The venter is very narrow, about 3 mm. in breadth;
it has no obvious nodes, but, as iu the type, faint undulations may be felt with
the finger on the ventro-lateral angles. The sutures are quite different, but
have the same general character. The first lateral saddles are quite
distinct on the two sides, owing to the asymmetry of the ventral lobe.
« Figured as Engonoceras retardum n. sp. Hyatt, Pl. XV, figs. 15-17.
ENGONOCERATIDE. 161
The sixth saddle on the left side is bifid; the seventh is broad and
symmetrically and deeply bifid, looking like two entire saddles; the eighth
has a large, slightly bifid, outer and a tongue-shaped inner arm; the tenth
is bifid. ‘The ninth and tenth can be reckoned in several different ways on
account of the peculiar formation of the lobes, either as above, or the inner
arm of the ninth be called the tenth and what is here named the tenth can
be classed as the eleventh, or, on account of shortness of the lobes, the
whole may be considered as a single broad saddle with three arms, the
outer and inner arms bifid and central arm narrow and entire. The
eleventh saddle is trifid and broad, the twelfth and thirteenth entire, and
the last is on the line of involution. On the right side the first lateral
saddles, on account of the asymmetry of the ventral lobe, are narrower and
the second is much reduced. The second to the seventh are entire, the
eighth and ninth are symmetrically bifid, the tenth to the thirteenth are
entire. The twelfth and thirteenth saddles alone correspond or are
symmetrical, bilateral on both sides of the body. The lobes have a ten-
dency to become irregular at their terminations and are long and narrow
on both sides and more alike than the saddles.
There is also a large fragment of an example of this species in its
gerontic stage, or of an undescribed species, associated on same mount
with E. subjectum (No. 10755 Collection Boston Society Natural History).
The diameter from line of involution toward venter as far as fragment
goes is 68 mm. There are only a few millimeters wanting externally,
since part of the first saddle is present. There are apparently nine
saddles only on the side, all entire except the seventh, eighth, and ninth,
which are bifid. The first to fourth lobes are long and narrow and the
saddles stout but phylliform. These sutures belong obviously to a very
aged shell, since out of nine sutures visible the eighth is the first that does
not slightly overlap and the last four overlap progressively more and more.
The absence or very slight development of the outer lines of nodes
and the absence of distinct ridges on the ventro-lateral edges of the venter
distinguish this species from EF. subjectum. The sutures of these two run
closely together, although the saddles and lobes of this form are somewhat
stouter and broader at the same age than in 2. subjectum.
Locality: McPherson County, Kans.
Age: Comanche series, iowa shales.
MON XLIV—03 11
162 PSEUDOCERATITES OF THE CRETACEOUS.
EXNGONOCERAS SERPENTINUM (Cragin).
Pl. XIX, figs. 7-14; Pl. XX, figs. 1-5.
Sphenodiscus belviderensis var. serpentinus Cragin, 1900, Colorado Coll. Studies,
Vol. VILL, p. 31, pl. 2, figs. 4-6.
Three casts of this species (Loc. No. 1489) are well preserved in a
matrix of hematite. The diameter of one (1489 b) is 58 mm., the volution
is 29 mm., the umbilicus 7 mm.; the same volution opposite, measured
from lines of involution to venter, 22 mm., no shell being present.
The involution conveys the larger part of each outer whorl, but the
internal volutions are plainly visible in the umbilicus and the involution is
obviously much less in the younger stages than in adults. The volutions
are much compressed. The venter is, however, flattened and slightly con-
save in the ephebic stage, and in the gerontic stage it becomes asymmetrical
and sinuous through the development of the large tubercular terminations
of the alternating costee. In the ephebic stage the costee are sigmoidal and
only slightly developed; in the gerontic stage these become broad on the
outer parts with an external and internal line of nodes, and become obscure
internally or umbilicad of the second row of nodes, but they are obviously
confluent to the internal or third line of smaller nodes on the umbilical
shoulders. These nodes, like the costz, come in on the casts at a late
ephebie substage, the side of the younger whorls being smootli. The
tubercles of the outer line in the one specimen (1489 b) are sharper and
the costee at the points convergent, whereas in the second specimen from
the same locality the latter broaden out and the tubercular terminations
are more elongated ‘This, however, resembles those of the other specimen
in the ephebic and anagerontic substage, the marked elongation coming in
with the metagerontic substage.
A similar disposition to broadening out of costze is also observed in the
larger specimens in extreme age, but is not so marked and the venter also
remains narrower. The living chamber is not complete, but it must have
been about one-half of a volution in length on the line of involution. Other
specimens show the same, but none give the outer margins. The inner
lines of tubercles remain close to the umbilical shoulder, receding outwardly
very slightly in extreme age.
ENGONOCERATID®. 163
The variation between different specimens in external aspect of the
casts is not great except in the gerontic stage owing to the greater or less
development of the nodose costations, but the variations in the sutures are
such that no two specimens are alike.
The fourth suture on right side of figured specimen has eleven lobes
and ten saddles, and is only slightly curved apicad. The arms of the
ventral lobe are seen cutting deep into the lateral aspect. The inner
branch of the first lateral saddle is broad, entire, and club-shaped, as are
all other saddles, except the ninth and tenth, which are bifid. The depth
and size of the lobe that divides what is here assumed to be the first
lateral is so like other lobes that it is not always easy to determine whether
it is a marginal or really the first lateral lobe. The lobes are all clubbed;
that is, narrow orad and swelling-out apicad, and from first to seventh
show very faint digitations or indications of from three to four very minute
incipient marginal lobes, the fifth showing the equal and the remainder the
unequal numbers of these.
Specimen 1489a has short lobes and corresponding saddles like the
above, but narrow outer branches to the first lateral saddles and arms of
ventral lobe hardly apparent on the lateral aspect. ‘There are eleven lobes
and ten saddles easily distinguishable, i. e., not overlapping and similar to
those of the first specimen, but saddles narrower outwardly and broader
inwardly, and, what is more remarkable, the seventh, ninth, and tenth are
bifid, the eighth, which is bifid in the first specimen, being entire in this.
Specimen 1489¢ has such distinct sutures that one hesitates to place it
in the same species with those marked 1489a and 1489b. The sutures are
more deeply curved apicad, the outer five saddles and lobes longer and
narrower, and the inner ones broader and flatter. There are, however,
eleven lobes and ten saddles visible, as in the others, and the age is about
the same. The sutures are, however, closely approximated, so that the
lobes slightly overlap even in the ephebie stage and form columns except
along the lines of the first to the second. The ninth saddle alone is bifid,
all others being entire
The discoidal aspect of the young in the umbilicus can be plainly
seen in this specimen. The sutures on the left side have the same general
character, but differ in details from those of the right side. The outer
saddles are alike, but the inner ones are narrow and more numerous.
164 PSEUDOCERATITES OF THE CRETACEOUS.
The fragments from Denison consist of an almost entire gerontic living
chamber and one somewhat more imperfect one of the same age, a smaller
fragment of part of ephebie living chamber and last suture. This last
shows that in the ephebic stage the venter is smooth, narrow, concave, and
has no tubercles, but is bordered by two smooth ridges. There are nine
lobes and nine saddles, the seventh and eighth saddles being bifid. The line
of involution is occupied by a minute lobe, as it is also in other specimens.
There are five dorsal lobes between this and the antisiphonal lobe on each
side. he first dorsal saddle next the antisiphonal is entire, the second and
fifth are bifid, the rest are entire. The third dorsal lobe was bifid, the
remainder on both sides of this were entire and narrower. The antisiphonal
lobe was narrow and bifid. The sutures of an early ephebic or late neanice
substage in one of these showed that the notation of the saddles in this
group is correct, and that the first lateral has, as stated, two unequal arms,
the inner being really an adventitious saddle derived from the inner side
of the first lateral. The outer saddles and lobes are similar in outline to
those of some specimens from northeast of Gainesville, but the inner saddles
and lobes are shorter and broader.
A specimen from Denison, kindly lent me by Prof. F. W. Cragin [is
also figured and is probably one of the types of his variety serpentinus now
raised to specific rank].
This species is distinguishable from others by the extremely late stage
to which the protengonoceran venter—i. e., the concave venter bordered by
two ridges—is retained. Practically it lasts throughout the ephebie stage,
and the engonoceran stage is passed through with great rapidity. In this
the venter is flat and bordered by weli-defined elongated tubercles, and
consequently there is a quick appearance of the senile stage with elevated
convex venter between large elongated nodes. It should be noticed that
one of the varieties imitates the sutures of [. subjectum in the shape of the
saddles and lobes, but these remain characteristically simple in outline
(Pl. XIX, fig. 11). Some varieties have bifid saddles and some do not have
them. The dividing marginals of the saddles enlarge by growth when they
occur, until they often form lobes practically inseparable from others.
Locality: Four and one-half miles northeast of Gainesville and
Denison, Tex.
Age: Upper part of Comanche series, Paw Paw beds, Washita group.
ENGONOCERATID 2. 165
ENGONOCERAS PIERDENALE (von Buch).
Pl. XX, figs. 6-13.
Ammonites pierdenalis von Buch, Abhandl. K. Akad. Wiss. zu Berlin, 1848, pl. 6,
figs. 8-10.
Ammonites pedernalis Roemer, 1852, Kreideb. v. Texas, Pl. I, fig. 3.
Engonoceras pedernalis Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, p. 183.
I have placed this here with a query, because I find it impracticable to
identify the young figured by von Buch with any form known to me.
The ventral lobe and saddle and the other parts of the suture might belong
to the young of a species a grade more complicated than any here described.
There is a row of elongated nodes close to the venter in von Buch’s figure,
but the presence of such ornaments is denied in the text, and the nodes are
said to be on one side and due to the exposure of the joints of the siphunele.
Roemer states that he had the originals in hand when making his deserip-
tion, and that the species was much larger than that described by him.
Neumayr mentioned this species as the type of his genus Hngonoceras*
and repeats the name ‘“‘pierdenalis” instead of ‘‘pedernalis,” the name given
by Roemer, and also repeats von Buch’s figure of the suture on PI. 7 of
Uber Ceratiten.
Von Buch and Neumayr also both deseribe the principal saddles as
bifid, a condition that does not exist in any specimen of the genus that I
have seen.
Locality: Texas.
Age: Fredericksburg group of Comanche series.
ENGONOCERAS PIERDENALE variety COMMUNE Hyatt.
Pl. XXI, fig. 1.
A fragment in U. 8. National Museum, No. 8301b, from Bell County,
Tex., is slightly crushed in the umbilical region, but has sutures and mark-
ings well preserved. At larger end the volution is 33 by 14 mm., at smaller
end 24 by 11 mm.
The venter is flattened and narrow, bordered by small elongated
tubercles rather numerous and closely set as in the adults of this species.
There is an inner row of tubercles, hardly perceptible median row, and
equally faint fold-like costations on the outer part of the volution, which
can be felt better than seen on this cast.
a@Amm. d. Hilsbild. Norddeutschlands, Paleeontogr., Vol. XX VII, 1880-81, pp. 138, 141.
166 PSEUDOCERATITES OF THE CRETACEOUS. 2
The ventral lobe is slightly asymmetrical to the left, giving rise to
considerable differences in the first lateral saddles on either side. The first
lateral on the right is bifid, the outer arm very broad and bifid, the mner
subdivided asymmetrically by a very minute marginal lobe. Beyond this
the inner arm is entire and quite large and phyllitorm. There are ten
saddles and nine lobes on this side All the former are entire except the
innermost, which is slightly bifid) The lobes vary from trifid to six-pointed.
On the left side the first lateral saddles have the usual bifid form without
further subdivisions. All the saddles appear to have entire phylliform out-
lines, but this may be due to the worn sutures. The first to fourth lobes
are slightly digitated, the fitth is faintly trifid, and beyond they are too
much worn to show the minute serrations.
On the left side the first lateral saddles have the usual bifid form, the
outer arm broad, pointed externally, and with only a slight indentation on
the margin. The second to seventh lateral saddles are entire and phylli-
form; the eighth is broad and deeply bifid, but is apparently only one
saddle; the ninth and tenth are entire.
The first to fourth lobes are faintly denticulated, the fifth and sixth
narrow and trifid. The seventh is totally unlike any other lobe. It seems
to be filed by a pointed saddle, the end bifid in one case.
There is also another specimen from the same locality, a cast with a
part of « living chamber preserved. This is about one-half of a volution
and in the gerontic stage, the last five sutures overlapping. The preceding
sixth or eighth, being in the ephebic stage, do not overlap. The lobes and
saddles are like those of the fragment just described, the sixth to the eighth
saddle on the right side being bifid and the ninth entire. The saddles in
old age, however, are flatter and the lobes become shorter.
The ornaments are the same as in other specimens, but the venter
becomes broader in proportion to age; tubercles persistent. The living
chamber is obviously nearly complete and must have been at least one-half
of a volution in length.
Three small fragments from locality No. 1554, Seven Knobs, near
Glenrose, Tex., have tubercles larger and more prominent, and although
the sutures vary they are near enough to belong to the same species.
The largest specimen over one-half of a volution is 52 mm. in diameter.
Probably, allowing for compression, this diameter is only 45 mm. The
ENGONOCERATID 2. 167
living chamber is about one-half of a volution and is nearly complete.
The venter broadens out, and this specimen seems to be outgrown, judging
from the approximation of the last three septa. The sutures are similar to
those of the preceding, but the seventh saddles are bifid.
Specimen from locality 1545, Chalk Mountain, near Glenrose, diameter
of volution 50 mm., partly estimated, has seventh saddle on the right side
bifid; all others external to this entire and phylliform, except, of course, first
lateral. This cast shows plainly that what is here counted as the second
lateral is an adventitious saddle derived from division of the first lateral
saddles, and the first lateral lobe is also an adventitious inflection arising
from a primitive marginal of the first lateral saddle.
A fragment from the Goodland limestone, Choctaw Nation, about 100
miles east of Preston, Tex., is considerably worn, but apparently of this
species. The volution is 33 mm. from line of involution to venter and is in
gerontic stage, the last six sutures overlapping. The venter is also rapidly
broadening, the gerontic tubercles and cost are larger than usual, and the
venter is more asymmetrical or zigzag in outline. There are nine saddles
visible, and the seventh and eighth are bifid; the outlines of others are
entire. The lobes, owing probably to attrition, are all entire.
A specimen in the United States National Museum, No. 22643, from
locality No. 973, near Cerrogordo, Ark., has a combination of characters
which appears to unite serpentinum with pierdenale. The sutures have the
broad, short saddles with flat bases, like those of serpentinum from near
Gainesville, but the size of specimen, nodes, and aspect are similar to the
typical fossils of prerdenale. The surface is worn down somewhat in this
east, and prebably these resemblances may be due to this cause. This east
is 91 mm. in whole diameter; transverse diameter estimated at 20 mm
A cast in the Museum of Comparative Zoology from Towash, Hill
County, Tex., is 56 mm. in diameter; the outer volution is 27 mm., the
umbilicus 8 mm., and the opposite part of same volution from line of
involution to venter 21 mm. This is an outgrown specimen, the last six
sutures overlapping those preceding, while in ephebic stage they are
separated by a distinct interval.
There are the usual lines of tubercles, and the costze on the outer part of
the volution become very decided, as in other aged specimens. The venter
is at first narrow, but this becomes much broader at the same time that costze
168 PSEUDOCERATITES OF THE CRETACEOUS.
inerease in size in last part of the outer volution. The venter runs from 2
to 7mm. in width on this one volution. The living chamber is complete
internally and is somewhat less than one-half of a volution in length. The
sutures resemble those of specimens described above except that there are
only seven saddles, the fifth and sixth very broad and bifid, the seventh
entire.
The first to third lobes are very slightly digitated; the rest are entire.
Bohm’s studies of the originals of the descriptions of this species have
been referred to in the generic description. Whatever doubts of Bohm’s con-
clusions may remain in the mind, it is surely safer to follow such an investi-
gator, who has worked over the original materials, than to indulge in
speculations with regard to the exact meaning of von Buch’s and Roemer’s
descriptions and figures, about which the most opposite opinions might be
reasonably entertained.
ENGONOCERAS SUBJECTUM n. sp. Hyatt.
Pl. XXL, figs. 2-6; Pl. XXII, figs. 1-5.
A good cast of this form (No. 431 in Museum of Comparative
Zoology) is 101 mm. in diameter, the inner oldest part of the outer volution
being partially destroyed, so that this could not be measured. The living
chamber was probably, when perfect, not less than one-half of a yolution
in length. The whole diameter was about 102 mm.; the transverse diameter
was decreased so by compression that the measurement near base of living
chamber could not be relied on, but this was 18 mm., the ventro-dorsal
breadth of side being at the same place 43 mm. The living chamber
having been excavated, it was possible to measure the interior volution in
the same line with the largest diameter given above. This was found to
be 73 mm., the largest volution being 40 mm., the umbilicus 7 mm., the
opposite part of same volution 26 mm. No shell was present on this cast.
The involution covers up the entire side of inner volution at diameter of
86 mm. This is found in several specimens, but does not appear to be
invariable. There are large nodes along the umbilical shoulders, very
obscure nodose folds along the central surfaces of lateral zones, and
prominent elongated alternating nodes along either border of the venter.
These last are finer in the ephebic stage than in the gerontic substages
At diameter approaching 100 mm. the venter loses the flattened aspect ot
ENGONOCERATID.UE. 169
the ephebic stage, becomes broader and slightly rounded, but still retains
the tubercles and asymmetrical aspect due to their prominence and alter-
nation. The gerontic living chamber is about one-half of a volution in
length on the ventral side, the dorsal side being absent.
The earliest suture in type No. 431 at diameter of 26 mm. from line
of involution to venter has eight saddles and seven lobes to the umbilical
shoulders. Beyond this they were not visible. The saddles are narrow
and phylliform or club shaped; the lobes also are clubbed and have primi-
tive denticulations. First lateral saddle is trifid and inner marginal lobe is
digitated, the second to fourth entire, fifth to eighth bifid. The ventral
lobe is longer than usual in this genus, but has the usual form, divided by
entire broad siphonal saddle. The first, second, and third laterals have
about five denticulations unequally divided, and the fourth is trifid. Later
in the gerontic stage the second to fourth saddles become either bifid or
have more digitations, and the digitations of the lobes increase to seven;
the phylliform aspect also increases.
When the volution is about 37 mm. in diameter from line of involution
to venter, there are apparently about the same number of saddles and
lobes, Pl. XXI, fig. 5. The lobes have more denticulations and the third
saddles are also faintly bifid. In another specimen, Pi. X XI, fig. 6, same
locality at about the same age, all the saddles and lobes are shorter and
broader in proportion, but decidedly phyllitorm, the lobes are more denticu-
lated, the first lateral saddles deeply trifid, the second to fifth saddles entire,
the sixth to the eighth (the last one visible) distinctly bifid.
A east (No. 10755, Boston Society of Natural History) from Bell County,
Tex., is 75 mm. in whole diameter. The entire volution is 39 mm. from
venter to line of involution; the umbilicus is 10 mm.; the diameter oppo-
site from line of involution to venter is 27 mm.
This is in the gerontic stage, the last five sutures overlapping. There
are ten saddles and nine lobes on the left side. The second to the sixth
are entire, the seventh to the ninth are bifid, and the tenth is entire. The
saddles and lobes have the elongated phylliform character of this species.
Locality: Gabriel, Williamson County, Tex.
Age: Comanche series, Washita?
The remarkable and highly instructive specimen described below is a
cast with an approximate diameter of 55 mm. It was received from Dr.
170 PSEUDOCERATITES OF THE CRETACEOUS. :
D. 8. Martin and came from Grayson, Tex. The sutures on the right side
possess a decidedly unique aspect, having a. first lateral saddle entirely
different from that of any specimen of this genus I have yet studied or seen
ficured. The whole aspect of these sutures indicates a new species, whereas
the sutures on the other side, although considerably abraded, are perfect
enough in places to show the ordinary form of first lateral saudle commonly
found in Metengonoceras. The sutures of the right side are more like those
of E. subjectum than those of L. pierdenale, but they are quite distmet from
both in the aspects of the saddles. On the right side there are nine saddles
and eight lobes. The first lateral saddle is broad and distinetly trifid. The
inner arm is broad and has the usual shape of other species, being pointed
externally and running well on to the venter. The central arm is a narrow,
small marginal saddle between two small entire marginal lobes; the inner
arm is narrower than the outer arm and phylliform. The second to the
fourth saddle are entire and phylliform, the fifth and remaining saddles
have flatter bases. The fifth is still entire and the remaining saddles also,
except the sixth, which is bread and bifid. This bifid character can be
detected only on the first part of the outer volution where the dividing lobes
are not abraded, but even this is open to some doubt.
The ventral lobe has the usual outline and is symmetrical in position;
nevertheless the first lateral saddles on the left side are quite distinct from
those on the right side. They have the usual bifid character of specimens
of other species, and there is nothing unusual in the outlines of the sutures
on this side. The seventh and eighth saddles are bifid, and the sixth is
entire. The ninth saddle is broader than on the right side. The condition
of the sutures on this side did not admit of more minute observations. The
first to the fourth lobes on the right side were of the usual form, but rather
coarsely serrated and similar to those of specimens from Bell County,
Tex., described above (collection of the Boston Society of Natural History,
No. 10755). It agreed also with the last ia the prominence of the middle
line of tubercles.
Locality: Grayson, Tex.
Similar sutures occur in a cast of this species kindly loaned me by
Prof. F. W. Cragin, and in this the eighth saddles are on the umbilical
shoulders and the broad ninth reaches to the line of involution; the second
to the sixth saddles are entire; the seventh to the ninth are bifid.
Locality: Varrant County, Tex.
ENGONOCERATID.®. Lal
The venter in this species remains concave and has a sharp ridge on
either side at the ventro-lateral angles, broken into waves by equally acute
but elongated nodes on the casts. Shells were not present. In old age
these nodes persist, but the ridges disappear and the venter becomes flat-
tened, and finally convex.
. A cast from Denison, Tex, Duck Creek beds, United States Geolog-
ical Survey, has very different sutures and is also somewhat different in
general aspect. The living chamber is complete in the inner borders and
is considerably less than one-fourth of a volution in length. It is in the
gerontic stage; the inner tubercles are large, and the outer ones, terminating
short, fold-like coste, are also very large. The venter is completely rounded
and much zigzagged in correlation with the large tuberculose alternating
folds and nodes of the costee.
The whole diameter is 92 mm.; the outer volution, which is somewhat
reduced by gerontic contraction, is 42 mm.; the umbilicus is 14 mm., this
being enlarged in proportion to reduction of gerontic part of volution, and
opposite from line of involution to venter is 36 mm, The saddles are quite
distinct from those of specimens described above, but have the same distinctly
phylliform aspect; the lobes are more alike and with similar serrations. There
are nine saddles on the right side. The first lateral has the same deeply
bifid form as in specimens of this species. The second to seventh have
rounded leaf-like bases; the eighth is still phyllitorm, but broadens out and
is bifid; the ninth is entire. The first lateral lobe is evidently very slightly
divided, but the second to the fifth are more richly denticulated than the
sixth and seventh and are faintly trifid (?); the eighth is perhaps entire, but
not plainly seen. he living chamber is shorter in this specimen than in
any other example of this species and the uodes are more like those of ser-
pentinum, while the sutures agree better with those of subjectum.
The principal distinction between this species and its allies of the same
genus lies in the more elongated phyllitorm saddles and lobes.
. ENGONOCERAS GIBBOSUM hn. sp. Hyatt.
Pl. XXII, figs. 6-10; Pl. XXIII, figs. 1-6.
The best example of this species is an entire cast in my collection from
Cook County, Tex. This has the median line of nodes along the central
line of the lateral surface, the outer distinct and short and no perceptible
172 PSEUDOCERATITES OF THE CRETACEOUS. :
costee between these. This cast, the type of the species, shows no gerontic
characters at the diameter of 93.5mm. The greatest transverse diameter is
at the umbilical shoulders and is 25 mm., the breadth of the side at the
same point being 50 mm. The sutures are quite different from those speci-
mens described below, but there is the same general character: the second
lateral saddle and the fifth are bifid; the sixth is unequally trifid; the seventh
is a compound saddle with two bifid arms; the eighth to the tenth are entire
or flat. he more gibbous sides, the prolonged stage during which the
nodes persist and are sharply defined, and the large number of bifid saddles
characterize this species. The sutures are the most complex, with exception
of Eng. roemeri, of any that have been so far descibed in the genus.
The largest fragment in the National Museum is about three-eighths
of a volution. Widest diameter is 91 mm.; the distance from line of invo-
lution to venter is 50 mm. at the larger end and 38 mm. at the smaller end;
and the transverse diameters are 20 mm. and 16 mm., respectively. This
specimen was probably entirely uncompressed. The venter is narrow and
flat and the sides are slightly gibbous and highly convergent outside of the
middle row of obscure nodes. Between these and the umbilical shoulders,
however, a flattened zone is developed, which may even slightly slope
inward The usual row of nodes is present on the umbilical shoulders,
and also the rows of alternating tubercles on each side of the venter. The
latter are sharp and well formed, elongated, and sufficiently numerous to
give a decidedly zigzag aspect to the narrow venter.
The venter is flat in the early part of the neanic stage and much
broader in proportion to the volution than in later stages, as it is in most
species of this genus. The volution has more flattened sides at this age,
and the involution begins to cover up the volutions to the umbilical
shoulders even at this early stage.
The sutures are well separated, as in other shells of this genus, and
are very remarkable. There are on the right side ten lateral lobes and
eleyen saddles at the larger end of this fragment and the same number at
the smaller end. These are more difficult to count and quite different on
the left side. The ventral lobe is symmetrical and of the typical form.
On the right side the first lateral saddle is bifid, the outer arm short,
broad, and spreading, the inner also broader than in most other forms;
the outer is subdivided by a minute marginal or slightly and unequally
ENGONOCERATID A. lect
bifid; the inner arm is slightly trifid in nearly all the sutures, and this
becomes more apparent in the older sutures. The lateral saddles are
broadly phyllitorm. The second laterals are obscurely and equally bifid
in all the sutures; the third shows a faint tendency to become bifid only in
the older sutures; the fourth seems to have a similar tendency, but this does
not become demonstrable, and it must be described as narrower at the base
and entire. The fifth is bifid in the younger sutures observed, and becomes
more distinetly bifid with age; the sixth is narrower and entire; the seventh
is equally bifid; the eighth is also equally bifid, but the inner arm is
unequally subdivided by a minute marginal; the ninth is also equally bifid,
and each arm is also bifid with a minute marginal lobe; in some sutures
both are unequally divided and in others the outer is symmetrical, the inner
asymmetrical; the tenth is small and entire, and the eleventh is very broad
and is subdivided by a minute marginal lobe introduced on this volution,
and the outer arm shows a tendency to broaden and become bifid in the
older parts of the same. The saddles are phylliform but rather short and
stumpy from second to sixth, then they become very broad and less phylli-
form; the lobes have the usual narrow bases between the expanded bases of
the saddles and spread out apicad between the phylliform saddles. These
are all apparently unequally subdivided, and the digitations and serrations
are somewhat more numerous in the second to the fifth laterals than in most
other species. The first and sixth are simply trifid, the seventh and eighth
bifid, the ninth and tenth entire.
On the left side the first lateral saddles have a narrower outer arm,
divided by a deeper marginal lobe, and the inner arm is not so broad and
shows only a faint tendeney to become bifid. The second lateral is more
distinctly but unequally bifid; the third shows a faint tendency to a trifid
undulation; the fourth is entire; the fifth is faintly bifid; the sixth is dis-
tinctly but asymmetrically bifid; the seventh is equally and deeply bifid;
the eighth is very broad and also deeply bifid, the outer arm has the margin
faintly undulated into four nearly equal marginal serrations, the inner arm
is asymmetrically bifid; the ninth is also unsymmetrically divided, the
outer part or arm is very broad, rather rounded basally and undulated into
three minute serrations on the margin, the inner arm is a minute saddle;
the tenth saddle is like that of the right side, but faintly bifid in the first
sutures seen; the eleventh saddle is narrower than on the right side and
174 PSEUDOCERATITES OF THE CRETACEOUS. ‘
entire. The lobes are all shorter, with broader ends apically and with less
complex digitations than on the right side.
One small specimen, a cast from locality 1492, 15 miles west of
Denison, Tex., has a diameter of 46 mm., outer part of volution, 23 mm.;
transverse diameter, 11 mm.; umbilicus, 7 mm.; and opposite diameter from
line of involution to venter, 16 mm.; transverse diameter, 7.5 mm. This
has the same shape of venter and general aspect. The nodes of the inner
line are present as elongated costa, which are most prominent at the
umbilical shoulders and much inclined orad. Very obscure nodes could
be felt over the more perfect surface of the cast along the centran lateral
area. The cast was too imperfect along the venter to observe nodes, but
at the beginning of this volution on a small bit of the shell of the venter
exposed by excavation there were smooth ridges at the ventro-lateral
angles, and the venter was concave.
The sutures in this are crowded together unusually close for shells of
this genus, the inner lobes and saddles overlapping slightly, beginning with
the third lobes and fourth saddles. It is probably a dwarfed form of this
species, since in the earlier part of same volution the sutures are well sepa-
rated, as in other forms.
The ventral lobes are obliterated, but sufficient of the first lateral
saddles remain to show that they were unequally bifid and that the outer
arm was also bifid, the inner arm entire and quite large. The seeond to
fourth saddles on the left side were broad and entire, the fifth to seventh
symmetrically and deeply bifid, the eighth very broad and unequally bifid,
the outer arm faintly bifid, the ninth alone entire. There is considerable
variation on the right side, the sixth saddle is not deeply bifid, the seventh
is unequally bifid, the eighth is like that of the left side, but the bifidity of
the margin of the outer arm is more pronounced. The ventral lobe is
symmetrical, but so much worn down that no observations were practicable
except at two of the sutures, when it seemed to have the usual generic
form. ‘The living chamber was not present in either of the above-described
specimens.
A small cast from Bell County, Tex., No. 8301a, about a fourth of a
volution, is 23 mm. in diameter from line of involution to venter, transverse
diameter 14 mm., two lines of tubercles and median line of elevations well
defined, venter distinctly concave. The sutures appear to have more
ENGONOCERATID 2b. 17d
resemblances to those of the older stages of this species than to any others.
The ventral lobe is narrow and slightly asymmetrical to the left, but the
first lateral saddles on both sides are alike. They are both bifid, the outer
arm is entire but is blunter than usual on the venter. The first to sixth
saddles are otherwise like those of the specimen described above; the sev-
enth to ninth saddles, seen only on the left side, are symmetrically bifid, the
tenth is entire. This bifidity of the internal saddles agrees with those of
uddeni, but the aspect-of the volution and the general form of the saddles
and lobes agree better with those of this species.
Locality: Cook County, Tex., 15 miles southwest of Gainesville and
15 miles west of Denison.
Age: Fredericksburg division of Comanche series.
ENGONOCERAS STOLLEYI Bohm.
P]. XXIII, figs. 7-9; Pl. XXIV, figs. 1-5.
Engonoceras stolleyi Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, pl. 5.
This species has the flattened venter, becoming alternately nodose and
zigzag in old age, as is characteristic of this genus. It is not distinguish-
able from LE. pierdenale except in the sutures. 'The lateral saddles and lobes
are smaller than in any other species of this genus, and the first lateral
saddles are apt to have the inner marginal saddles tongue-shaped. This
peculiarity is noticeable in Bohm’s figure and in the large fossil (Pl. XXIV,
se)
Age: Fredericksburg group [?], Comanche series, Lower Cretaceous.
ENGONOCERAS COMPLICATUM hn. sp. Hyatt.
Pl. XXIV, figs. 6-8.
This is founded upon a cast from near Austin, Tex. The whole
diameter, partly estimated, is 73 mm., the outer volution is 39 mm., the
umbilicus 9 mm., the volution opposite (estimated) 25 mm. By the cast
alone this species could not be separated from Engonoceras gibbosum, but
the sutures are nevertheless entirely different. A better preserved specimen
might, however, show some external characteristic distinctions. There are
fourteen sutures visible on the outer volution; then comes a gap between
176 PSEUDOCERATITES OF THE CRETACEOUS.
them and those on the first quarter of the same volution. The entire
fourteen overlap, but the tenth, eleventh, and twelfth are nearer together
than any others. The ephebic sutures on the first-quarter of this same
volution are well separated. There are eleven slender saddles and ten
slender lobes on the left side. The first lateral is narrower than in any
other species and bifid, with tongue-shaped entire arms; the second and
third laterals are also entire and linguiform; the fourth to the ninth are
phylliform and bifid; the tenth could not be seen; the eleventh was entire.
The ventral lobe is narrower, deeper in proportion than in other
species. There is a smaller and contorted cast from Benbrook, Tex,
with similar sutures so far as the bifidity of some of the principal
saddles is concerned. It is very likely a variety of this species. The
markings, so far as can be determined, are similar. The living chamber is
about one-half of a volution, the last sutures overlap, and the shell was
evidently in the gerontic stage. The third lateral saddles were bifid, the
fourth was entire, the fifth to ninth were more or less phylliform and bifid,
and beyond this none were visible.
it differs from Protengonoceras emarginatum (Cragin) in having pro-
nounced lines of tubercles along the ventro-lateral angles and its greater
number of lobes and saddles, judging from the descriptions of that species.
The characteristics of the venter and the size as given by him indicate
a larger species, with venter more like that of Proten. gabbi. A small
specimen, a cast, from 15 miles west of Denison, Tex., has a diameter
of 46 mm.; outer part of volution is 23 mm.; transverse diameter,
11 mm.; umbilicus, 7 mm., and opposite diameter from line of involution to
venter, 16 mm.; transverse diameter, 7.5 mm. This has same shape of
venter and general aspect. The nodes of the inner line are present as
elongated cost, most prominent at the umbilical shoulders and much
inclined orad. These disappear as they pass the centran lateral surface.
Nodes could not be seen nor felt over the perfect surface of the cast, and
none were visible at the beginning of this volution on a small bit of the
shell of the venter exposed by excavation.
The sutures in this specimen are crowded together unusually close for
shells of this genus, the inner lobes and saddles overlapping slightly,
beginning with the third lobes and fourth saddles. It is probably a
ENGONOCERATID_®. 77
dwarfed form of this species, since in the earlier parts of same volution the
sutures are well separated, as in other forms.
The ventral lobes are obliterated, but sufficient of the first lateral
saddles remain to show that they were equally bifid and that the outer arm
was also bifid the inner arm entire and quite large. The second to fourth
saddles were, on the left side, broad and entire, the fifth to seventh
symmetrically and deeply bifid.
Locality: Near Austin and Benbrook, Tex.
Age: Fredericksburg group, Comanche series.
ENGONOCERAS EMARGINATUM (Cragin).
Sphenodiscus emarginatus Cragin, 1893, Geol. Surv. Texas, Fourth Ann. Rept., p. 245.
According to Cragin’s description, this species has the concave venter
until a late stage, but has the tubercles and sutures of this genus.
ENGONOCERAS ROEMERI (Cragin).
Sphenodiscus roemer’ Cragin, 1893, Geol. Surv. Texas, Fourth Ann. Rept., pl. 46,
fig. 1.
Cragin describes this shell as having “venter narrowly truncate, the
ventro-lateral angle at first sharp, becoming on the body-chamber subtu-
berculate-sinuous.” This and the general outlines of the sutures, if they are
supposed to be deprived of their marginal saddles, as they must have been
in the young of this shell before these were developed, has caused me to
refer the species provisionally to this genus The sutures are, however,
obviously more complex as figured by Cragin than in any other known
form of Engonoceras. ‘The principal saddles are all bifid, trifid, or quadrifid,
and the smaller saddles inside of what appears to be the fourth saddles are
mostly bifid.
Mr. Stanton has written as follows regarding this form:
According to Cragin, this is from the ‘‘alternating beds’”—that is, the Trinity
division—not Fredericksburg, as given in your MS. [f this be true (and Mr. Taff’s
stratigraphic data look all right), the form is probably the oldest one of this group
that we have from the Comanche series.
Locality: Iredell, Bosque County, Tex.
Age: Comanche series, Glenrose beds.
aSee p. 157, where this species is doubtfully referred to Protengonoceras.—T. W. 8.
MON XLIV—03 12
178 PSEUDOCERATITES OF THE CRETACEOUS. :
NEOLOBITES Fischer.
The sutures of this genus have, perhaps, simpler outlines than those
of any other Cretaceous ammonoid, and have been supposed to place the
genus somewhere near Tissotid. They, however, differ decisively from
those of any of this group in having long phylliform saddles and a very
peculiar ventral lobe. The form, ornamentation, and old age of the species
from Tunisia, described by Peron, would place it in the genus Placenticeras,
if no sutures were visible. But the sutures and ornamentation agree with
those of Engonoceras, and show that it is probably a member of the same
family. Choffat’s researches have placed this conclusion on a secure footing.
His Neolobites vibrayeanus may not be identical with d’Orbigny’s species,
but it is surely a close ally, and he gives the sutures in full, and these
show the ventral lobes and siphonal saddles and first laterals to be similar
to those of Engonoceras. If the young, when seen, prove to have a similar
development, the evidence will be complete.
NEOLOBITES VIBRAYEANUS (D’ORBIGNY).
Ammonites vibrayeanus VOrbigny, 1540, Terr. Crét., pl. 96, figs. is.
Neolobites vibrayeanus Choftat, 1898, Faune Crét. du Portugal, Vol. I, 2d series, pl.
5, figs. 2, 5 (not figs. 3, 4.)
This species as figured by d’Orbigny has led to great confusion, owing
| > J Oerw to} ’ too}
perhaps to the absence of a sufficient representation of the details. * Chottat
has fieured a species from Portugal which, if not identical, is probably
5 5 , : 2
similar to d’Orbigny’s species. All the characters coincide with the posi-
tion here eiven to this form. A number of species are confused under this
to}
name, but the data given are not sufficient to separate them.
Locality: France and Portugal.
Age: Cenomanian.
NEOLOBITES CHOFFATI ni. sp. Hyatt.
Pl. XXV, figs. 1-4.
Neolobites vibraycanus Choffat, 1898, Faune Crét. du Portugal, Vol. I, 2d series,
pl. 5, figs. 3, 4 (not figs. 2, 5.)
This is obviously distinet from vibrayeanus, as is shown by the broad
venter and distinct sutures as well as the more gibbous form.
Locality: Portugal.
Age: Cenomanian.
ENGONOCERATID®. 179
NEOLOBITES PERONI n. sp. Hyatt.
Neolobites vibrayeanus Peron, 1890, Moll. Crét. de la Tunisie, pl. 18, figs. 1, 2
A highly compressed shell with narrow flat venter bordered on either
side by a line of small, closely set tubercles with numerous costee on the
flat sides, focussed into a very few large nodes near the umbilical shoulder.
The involution is almost if not quite complete. The umbilicus is not
figured in Peron’s figure, but it must have been very small. In extreme
age these nodes recede farther from their first position, the ventro-lateral
lines of small tubercles disappear and the venter becomes elevated and is
represented in the last stage as subacute. There are five or six lateral saddles
in this species, according to Peron’s drawing. Peron considered this
form to be distinct, but did not describe it as a new species.
Locality: North Afriea.
Age: Cenomanian.
©
METENGONOCERAS n. gen. Hyatt.
The shell is compressed as in Engonoceras and the involution covers
the greater part of the sides of the internal volutions. Broad, fold-like
sigmoidal costxe are present in some species and faint tubercles have been
observed in rare cases on casts. No well-preserved shells have been so far
seen nor described The venter in the neanic stage is comparatively broad
and slightly concave; in the ephebic stage it becomes very narrow, but
retains a linear concavity; in the full ephebic stage it becomes acute, and
in gerontic stage subacute and then rounded. The sutures do not differ
materially from those of EHngonoceras; the distinction, so far as known, lies
in the development of the venter and abseuce of nodes. The young were
similar to the adults of Protengonoceras, as are those of other genera. The
principal or outer lateral lobes and saddles are short, the lobes narrow and
entire between the entire and more or less rounded, often phylliform bases
of the principal saddles. The apical ends of the lobes are denticulated, but
the marginals are entire, pointed, and the saddles blunter but also entire.
The smaller inside of the principal outer saddles are often bifid. The
ventral lobe is narrow orally, very short and broad apically, with two
entire arms, and is divided by a depressed but more or less subacute entire
siphonal saddle. he first lateral saddles in most species are broad and
180 PSEUDOCERATITES OF THE CRETACEOUS.
.
bifid, the outer arms more or less acute at the outer angles of the bases, and
the inner arm narrower and tongue-like. One of the marked characters
of this genus is the absence of differentiation between the parts of
the suture at later stages of growth. The principal lateral saddles and
lobes can not in many specimens be distinguished from the so-called
auxiliary laterals, and I have not attempted to do this in my descriptions.
In some specimens, on the other hand, especially young ones, there seem
to be plainly only three principal lateral saddles or lobes, but in others
there seem to be four or even five. The metaneanic substage in one
species showed the primary division of the primitive first lateral saddle into
three, and in several specimens in a late neanic substage it seemed obvious
that this subdivision was maintained and that the first lateral of the
derivative or principal series became bifid late in the life of the shell. First
lateral saddles are therefore morphologically double, even when they are
so fully divided that they have to be considered as two saddles, as
in Metengonoceras dumbli. In most species there is no difficulty in seeing
this, but in about all of them the line between the three principal laterals
and the auxiliaries can not be drawn, nor between the principal lobes and
the auxiliaries. Here, however, as in Hngonoceras, there are but three
principal laterals, if the first lateral is properly defined as double or bifid.
The subacute venters of the species in this genus have lead to confusion
with Sphenodiscus and its allies. The ontogeny of the latter separates the two
generically, but the latter might be considered an accelerated form of the
same family, as stated above in the description of the family, but for the
sutural characters which show that Sphenodiscus belongs in the Placenticeran
stock.
METENGONOCERAS INSCRIPTUM n. sp. Hyatt.
Pl. XXV, figs. 5-9; Pl. XXXVI, figs: 1—#
One entire cast is 80 mm. in diameter. The diameter from line of
involution to venter is 42 mm. at largest part, the transverse being 16 mm.
Both measurements are a trifle short of what they would be in a more
perfect cast. Opposite this the same diameter is 29 mm. without shell,
the umbilicus beg 9 mm.
A fragment somewhat younger from same locality was not compressed
so as to destroy the shape. This had the same form, but was not so con-
cave near the umbilicus and had no folds. The volutions were flat om the
ENGONOCERATID 25. 181
venter in the neanic stage, aud were obviously similar to Protengonoceras in
their young. The smaller fragment, nearly one-half of a volution, with
center partly preserved, is 52 mm. in diameter, and the venter is worn, but
in places where sutures are perfect the venter is narrowly rounded. In the
largest cast, at about the same age, | was able to demonstrate by excava-
tion that the shell, although very narrow, was thick and distinctly concave
ou the venter. There were apparently no large tubercles at any stage.
The first lateral saddles in the small fragment, at a diameter of over 52 mm.,
were broad, very short, and had the inner angle furnished with a large
marginal lobe and saddle.
The second to fifth saddles on the right side, and the second to sixth
on the left side, are entire, the sixth on the right and seventh on the left
being the first of the bifid saddles. The other saddles are all bifid, except,
perhaps, the innermost pair, but this was not seen.
The lobes are too much worn down to show their minute digitations
except in a general way. ‘The ventral lobe and minute median saddle are
present and the first lateral saddles are narrow. On the youngest and
least-worn part of the larger specimen on the right side, the first lateral
saddles show slight marginal lobes and saddles at each of the inner angles,
but there are minute marginal lobes on the outer parts of these saddles.
Several of them show this division, and one is distinetly trifid. On the
older parts of the same specimen they are, however, distinetly entire as in
the other fragment, and this I think is the normal character. The wearing
to which it had been exposed caused me at first to count three entire
saddles on the left side and four on the older parts of the same volution.
It is obvious, however, that it is the sixth saddles that are bifid on both
sides. The remaining saddles are bifid to the line of involution. In both
of these specimens there are ten saddles and nine lobes, but there was
probably in each a lobe on the line of involution. The youngest sutures
were about 5 mm. distant, but the last nine lost distance rapidly and were
more or less irregular, and in the last four the second lateral saddles
overlapped slightly the second lateral lobes.
The larger cast has three much-worn fragments of the attached valves
of an ostrean on the right side, which had evidently been exposed above
the calcareous mud while in the same condition as at present, namely, a
distorted fossil cast, and the ostreans grew upon the surface of the cast
itself. That the cast had already suffered from attrition and compression
182 | PSEUDOCERATITES OF THE CRETACEOUS. ;
was shown by the accurate fitting of the ostrean shells into the irregularities
of the broken and worn surface. A few other lower valves were removed
to study the sutures, but in no case could | find any remnants of the shell
of Engonoceras between the bases of attachment of the lower valves of the
ostrean and the surface of the cast. The specimens still left upon the cast
show these facts also. The smaller specimen was much smoother and clean.
A much-distorted fragment from another locality, 9 miles from Austin
on Beecaves road, of what seemed to be the gerontic stage of this species
is 85 mm. from line of involution to venter and this is very near to the
actual diameter in a perfect cast. The greatest transverse diameter is 35
mm. and is somewhat greater than in a perfect cast of the same age. This
specimen, however, has the sutures well shown on the right side, and the
differences, with one exception given below, when compared with the first
specimen described, can be accounted for as probably due to greater age.
The saddles and lobes are all much nearer together, the overlapping begin-
nine between the third saddle and second lobe. The curvature was the
3
to}
same as in the smaller specimen.
The tenth saddle is the first bifid one and the remainder are bifid and
near the umbilicus become very broad. .
This difference can not be accounted for by supposing that the seventh
and eighth saddles have become completely divided by the advance in
development of the marginal lobes, thus adding two saddles to the series,
but indicates some original variation in this shell.
The ventral lobe could not be defined and the condition of the other
lobes only enabled an observer to see that they were digitated and near the
umbilicus they were too much worn to say even this much. The length-
ening out of the saddles by growth does not decrease the phylliform aspeet
of the bases and the lobes become narrower and longer without apparently
altering much in general outline.
Locality: Twelve miles northeast of Decatur, Tex.
Age: Fredericksburg group, Comanche series, Lower Cretaceous.
M&TENGONOCERAS INSCRIPTUM var.?
This is a fragment of a volution of a large specimen, showing only a
part of one side. It is, however, interesting, for the characteristics of the
lobes and saddles given on Pl. XXV, fig. 8, show variations in the forms of
these. A specimen from west of Walnut Springs, Tex., kindly loaned me
ENGONOCERATID.2©. 183
by Professor Cragin, shows the subacute venter. The eighth saddles are
bifid in this fragment and there are only ten on the right side, with large
unequally bifid first laterals as in large fragment described above.
Locality: Fifteen miles west of Denison, Tex. Locality 1492, U.S.
Geological Survey.
Age: Fredericksburg group of Comanche series.
One fragment is 55 mm. from line of involution to venter without the
shell. The first lateral saddle is deeply bifid, and, counting this as one,
there are only five entire saddles, some of which, probably owing to wear,
appear to show a faint tendency to become bifid. The sixth to the ninth
saddles are distinctly bifid; the tenth is a very broad saddle with three
minute marginal lobes, and the eleventh is another broad saddle which is
entire to the line of involution. On the opposite or right side the broad
tenth saddle is divided into two bifid saddles, so that there are obviously
twelve on that side.
Locality: Cow Creek, Travis County, Tex. No. 19105, U.S. National
Museum.
METENGONOCERAS AMBIGUUM n. sp. Hyatt.
Pl. XXVI, figs. 5-7.
One nearly entire cast of this form is 79 mm. in diameter, the last
volution 44 mm. from line of involution to venter, the umbilicus 6 mm., and
the opposite part of volution 29 mm. The greatest transverse diameter
through median surface is 17 mm. and is somewhat less than in a perfect
specimen.
The sutures have smaller saddles than at the same age in M. inseriptum,
are also less distant throughout, become still more approximate in later
stages, and are straighter. There are thirty septa in this specimen to twenty-
four in inscriptum at same diameter. The sixth saddles were bifid on both
sides.
Fold-like costze along the inner part of the volution are plainly visible
and there are small nodes along the ventro-lateral angles, the venter being
here famtly sinuous. The venter was much eroded, but in two places it
showed a narrowly rounded area and on the end of this volution is subacute.
Excavation was not very successful and I could only demonstrate that the
venter was extremely narrow in the ephebie stage and perhaps not distinct
from that of Eng. inscriptum at the same age.
184 PSEUDOCERATITES OF THE CRETACEOUS.
.
This cast was considerably worn. The right side was free of encrusting
ostreans; on the opposite (left) side there were a few, some of which were
removed. No shell was found between these and the cast. They had
evidently grown upon this cast and not upon a living or dead shell. This
can also be seen by studying the remaining shells, one complete lower valve
and part of another.
Locality: Nine miles from Austin, Tex., on the Beecaves road.
Age: Comanche Peak limestone, Fredericksburg group of Comanche
series, Lower Cretaceous.
METENGONOCERAS ACUTUM n. sp. Hyatt.
Pl. XXVI, fig. 8; Pl. XXVIII, figs. 1, 2.
The type specimen of this species in Boll collection in the Museum
of Comparative Zoology is a fragment, but this shows the whole diameter
to have been approximately 100 mm. The outer volution from line of
involution to venter is 54 mm, the umbilicus 5 mm., and the same volution
opposite must have been about 40 to 41 mm.
The form is much compressed and involute, with more acute venter
than in M. inscrivtum. The umbilical shoulders also in this species are
more prominent and entire, and short but distinct, broad, fold-lke costa
are present near the umbilical shoulders, but do not cross them. There
are no tubercles on the fragments observed. '
The marginal lobes of the first lateral saddles on both sides are narrow
and divided by a minute marginal saddle or bifid. The first laterals are
unsymmetrically trifid, the second to the fourth are symmetrical and quad-
rifid, the fifth is of the same type but not regularly divided. All of these
are very narrow at the bases between the expanded bases of the saddles and
spread out apicad into the marginal divisions. The sixth lobe is narrow
and bifid, with a small marginal saddle, and the seventh similar, but with a
larger tongue-like marginal saddle, and the minor lobes on either side of
this are also subdivided or bifid. The eighth and ninth are distinctly but
very faintly trifid, and much longer than the narrow marginal lobes
described above as dividing the broad saddles of this part, which are faintly
bifid. The tenth lobe was visible but not distinet enough for description.
Both specimens were too much crushed in the central parts to give
any accurate data for the description of the younger stages. Nevertheless
ENGONOCERATID_®. 185
there are strong indications that the venter became acute in an early
ephebie substage.
The matrix of these specimens is a red, apparently calcareous, clay
stone, and indicates a distinct formation from that containing the species of
Placenticeras cited from the same locality and also in the Boll collection in
the Museum of Comparative Zoology. They have remnants of the
nacreous layer and one has the shell still left in the umbilicus. The
interior is so much crushed together that it is impossible to say that the
venter was or was not concave in the internal volutions. Certainly, so far
as the cast goes, the outer volution was unquestionably subacute.
Three fragments in Cragin’s collection from the Grayson marl, one-
half to three-fourths mile southeast of the Union Station, at Denison, Tex.,
have the phylloidal saddles and long complex lobes of this species and also
subacute venters. The last volution of one of these fragments reaches
ventro-dorsal diameter of 60 mm. while still septate, and has a transverse
diameter of 24 mm. The sutures, however, are too much abraded for
efficient observation.
The peculiar first lateral saddles of this species, the extremely phylli-
form saddles, narrow lobes with spreading and digitate extremities, and
straightened sutures, separate this from M. inscriptum. The larger size of
the lobes and saddles enables one, as well as the more persistent acuteness
of the venter in the gerontic stage, to distinguish it from MM. dwmbli.
Mr. Stanton has written as follows with reference to this fossil: ‘TI
think this is certainly from the Upper Cretaceous and probably from the
Eagle Ford shales, like the other specimens with the same locality label.
Such brownish-red concretions are common in weathered portions of the
Eagle Ford shales.”
Locality: Elm Fork and West Fork (Horton’s mill), Dallas County,
ex:
Age: Probably Eagle Ford shales, Colorado group, Upper Cretaceous.
METENGONOCERAS DUMBLI (Cragin. )
Pl. XXVII, figs. 3-14.
Sphenodiscus dumbli Cragin (pars), 1893, Geol. Surv. Texas, Fourth Ann. Rept.,
p. 248, pl. 44.
A superb specimen in collection United States Geological Survey,
diameter 94 mm., although in three pieces and with nepionic stage and part
186 PSEUDOCERATITES OF THE CRETACEOUS. .
of outer volution absent, is otherwise perfect and shows many essential facts
with regard to the affinities of this genus. The last half of outer volution
or greater part of living chamber is in the gerontic stage. This shows that
the living chamber was at least one half of a volution in length. Cragin, who
had this cast in hand as part of his materials, describes his specimens as being
“very sharp in the young [my adult], becoming obtuse along the body-
chamber of adult [my old age] specimens.” The well preserved part of
the gerontic venter in this cast is 23 mm, long and for a few millimeters is
rounded, with two almost imperceptible ridges on the ventro-lateral angles,
then a hollow occurs as if the shell had been injured, and this is continued
to the end of the fragment by a very faint channel bordered by faint ridges.
The young in the nepionic stage has the usual rounded volution; the
paraneanic substage was compressed with flat sides, deep involution, and
broad concave venter, with entire, acute ridges on the borders. This stage
is, in other words, like the ephebie stage of Protengonoceras, as has been
already stated from examination of less perfect specimens. This substage
was introduced gradually by the intervention of a metaneanic substage
having a helmet-shaped section with a flattened venter and an ananeanic
substage with transitional characters between this and the nepionic rounded
volution, but not having the flattened zone on the venter. In the anephebie
substage the compression and flattening continues to increase, the involution
remains constant, and a very narrow channel still persists on the vénter.
In the full ephebie condition this disappears and the venter becomes
acute. In the paraephebic substage the venter is subacute, the sides a
trifle more convex, and volution somewhat broader in proportion to the
ventro-dorsal diameters, but these changes are slow until in extreme age,
the paragerontic substage, when, as stated above, the venter becomes
rounded. I have frequently alluded to the reinstatement by degeneration
at the end of a cycle or in the adult of characters analogous to those of
younger stages. In this specimen the rounded venter of the paragerontic
substage has a faint concavity, and this, after what seems to have been
some injury to the edge of the venter, becomes converted, as described
above, into a faint channel with ridges on the outer borders. There are no
marks of tubercles, nor cost, nor folds at any stage so far as these could
be seen.
ENGONOCERATID.®. 187
The sutures have short broad saddles with narrow lobes, digitated
only at the apical ends, and while the saddles remain about the same, the
lobes increase somewhat in the number of their digitations and in length
with age. They are quite different on the right and left sides. The
siphunele is eccentric to the right, and ventral lobe follows this organ, but
there is no very marked difference between the first lateral saddles in
consequence of this.
On the right side the first lateral has two branches so deeply divided
by a bifid marginal lobe that it is really split into two distinct entire
saddles, but these are more widely separated than in Meteng. acutum, and
are more nearly equal in size and aspect. Counting these as two saddles,
there are thirteen saddles—ten narrow, entire, and phylliform, and three
broad and bifid, the eleventh very deeply bifid, and the twelfth and
thirteenth successively less deeply divided. The first and second lobes
are bifid, the third to sixth bifid, but with four to eight digitations; the
seventh to tenth simply bifid; the eleventh and twelfth, especially the
eleventh, are divided by longer tongue-shaped saddles.
On the left side the differences are as follows: The ninth to eleventh
saddles are broad and bifid, the twelfth is broad and entire, the thirteenth
is very broad and has a sinuous base, and inside of this a very minute lobe
shows that there is a small fourteenth saddle. The eighth to the tenth
lobes are simply bifid, the eleventh is unequally bifid, but has no long
tongue-shaped marginal saddle; the twelfth is entire, and there is an
excessively minute marginal thirteenth, as stated above.
In the adult stage from the fifth saddles inward on both sides the sutures
overlap slightly and the outlines are easily separable, but in the last five
sutures this overlapping spreads to the third saddles and lobes and the out-
lines are more compressed. This is accompanied by a shortening up of
the saddles and lobes and a corresponding return of the younger proportions
and aspect.
In the metaneanie substage the primitive first lateral is divided into
three low broad saddles by simple indented marginal lobes, and the magno-
sellarian saddles are also divided, but the number of these was not ascer-
tained. There were, however, only a few of these.
Locality: Four miles east of Whitesboro, Tex.
Age: Eagle Ford shales, Colorado group, Upper Cretaceous.
188 PSEUDOCERATITES OF THE CRETACEOUS. .
PLACENTICERATID Hyatt.
The young are similar to the adults of Engonoceratide, having con-
cave venters bordered usually by continuous ridges with compressed volu-
tions, the lateral zones converging outwardly.” In later stages of genera
the venters are either coneave, flat, or rounded, but there is no true keel
present, although the venter may become acute in some species at a late
stage of growth. The volutions in the earlier stages subsequent to the
nepionic are apt to be more or less compressed, the venters assuming early
the characters described above, any further sharpening of the venter occur-
ring in later stages. The principal lateral saddles are, so far as known, bifid
in the young and show in most groups a tendency to become more or less
trifid in later stages. The multiplication of inflections of the suture lines
increases with the involution of the whorls by growth and they become
very humerous in some genera.
PLACENTICERAS Meek.
The species of this genus could be readily distinguished if it were not
for the great range of form in the gerontic stage, which occurs in dwarfed
as well as in large specimens, and is continually mistaken for the ephebie
stage.
The neanic shell is smooth, compressed, with at first a flat and then a
concave venter bordered by smooth, entire ridges on the shell and on the
easts, but has a stouter volution than later stages. It is, in other words, like
the ephebic stage of Protengonoceras in external characters, but the sutures
are of the Placenticeran type. Subsequently the ridges become tubercu-
lated, the venter becomes much narrower and the sides also tuberculated and
the volutions more compressed. These spines, nodes on the casts, are in
three rows, but may be completely absent in some shells, as they are also
in some old shells. In old age the venter again becomes flattened and
smooth, and finally broader and rounded.
The species are all connected so closely by intermediate forms that
distinct lines are difficult to draw between contiguous species.
The compressed and highly involute young show that those species,
like P. guadulupe, having depressed volutions with broad venters, are
senile forms in the phylum, or what I have named phylogerontic. They
PLACENTICERATID2. 189
are not scaphitoid, as stated by Munier Chalmas, except in the sense that
Scaphites is an extreme case of the same tendency to reproduce senile char-
acters early in the ontogeny and to such an extent that the ephebic form
becomes more or less influenced by them. The species form a series, there-
fore, leading off from shells, like P. syrtale in one direction into P. guada-
lupe and in the other into whitfieldi. The intermediate modifications
connecting this genus with Protengonoceras are probably partly represented
by Diplacmoceras, but this genus is not a primitive, although it seems to be
a phyloneanic form.
The solution of the species problem appears to lie principally in the
development of tubercles and the correlative stoutness of the volutions.
Shells having heavy tubercles in three lines usually also have sutural pecul-
iarities that enable one to distinguish them. The peculiarities of the gerontic
stage are also distinct, as will be noticed in the descriptions. In some spe-
cies the neanic stages are quite distinct in their sutures, although alike in
their forms at the same age, and perhaps with more materials the study
of these and the development of sutures may give good results. The
most highly modified form as compared with its own neanic stage is
certainly guadalupe, but although the sutures are complicated in outline,
they are not so complex as those of whitfieldi, and the modifications of
form are distinctly in a phylogerontic direction. The varieties of each
species and the development poiut to the most prevalent syrtaloid form
as presenting more than any other purely progressive characters. This
form has moderately compressed involute whorls, with three lines of nodes,
narrow venter, and steadily complicating sutures. The same variations in
the species and in the individual point consequently im one direction toward
guadalupe and in another toward whitfieldi. This last is reached through
species like stantoni and pseudoplacenta, in which the median lines of
tubercles become permaneutly obsolete and the outer and inner lines
become less prominent and in many specimens of whitfieldi are absent,
The interesting fact in this connection is that whitfieldi, which, as compared
with its own young, is the least modified of all the forms, has the largest
Dp)
shells, the least affected by gerontic degeneration, and at all stages the
most complex sutures.
These facts also show in a marked way the law of retardation of
development. This was joined by Cope with acceleration, but so far as
190 PSEUDOCERATITES OF THE CRETACEOUS.
my experience goes they are quite distinct. Retardation oceurs in
cephalopods in phylogerontie forms. Thus in this phylogerontie genus
the young is a highly modified, compressed involute shell in the neanic
stage; the adult in some species like guadalupe and the European depressum
may have additional modifications ending with a paragerontic stage also
tuberculated, but with peculiar broad venter and lateral nodes. In other
species, obviously closely connected, like pseudosyrtale, newberryi, planum,
and European congeners like grossouvrei and milleri, the first appearance of
tubercles occurs later in the ontogeny and they are present in their’ full
development only in the latest ephebic substage or gerontic stage. The
same law holds also in the series leading from syrtale through intercalare
and stantoni to whitfieldi. In some forms of syrtale and intercalare the
three lines of tubercles appear eartier than in the typical forms of the same
species and-in placenta.
In stantoni and pseudoplacenta this later appearance of tubercles
becomes invariable and correlates with the disappearance of the centran
line and a tendency to decrease in size of these ornaments on the venter
and umbilical shoulders.
In whitfieldi this tendency results in the total disappearance of the
tubercles in a large number of shells, three lines of tubercles being present
only in a very few shells and always of very small size, plainly individual
reversions. '
The sutures are simpler in outline and continue persistently to hold the
syrtaloid outlines, and are easily separable, except in extreme age, in all of
the guadalupan series, including not only the stouter forms like guadalupe,
but the highly compressed shells like planum. In the series leading up
to whitfieldi there is a marked gain both in complexity of outline and in
gerontic characters. This is apparent in intercalare and placenta, which still
retain the three lines of tubercles, and is still more pronounced in stantoni
and pseudoplacenta and culminates in whitfieldi. In these last the sutures are
similar to syrtale only in the neanic stage, and in whitfieldi they become
more rapidly complex in ontogeny than in other species and overlap to
such an extent that it becomes more difficult to separate them throughout
the ephebic and gerontic stages. This overlapping is a purely gerontic
character, and the species that show it during the ephebic stage are
therefore phylogerontic and to this extent degenerative in spite of the
PLACENTICERATID®. 191
inerease in complication of outlines of the lobes and saddles and their large
size. This phylogerontic character is also accompanied, as stated above,
by loss of ornamentation and retention throughout life of the compressed,
involute, smooth volutions of the neanic stage.
The living chambers are persistently one-half of a volution in length,
whether occurring in depressed or compressed shells or in dwarts, and the
apertures, so far as seen, have a short, blunt rostrum and low, broad lateral
crests.
Grossouvre’s careful descriptions and exceptionally fine figures of
the different forms included under the name of Placenticeras syrtale show
that while there exists in France and Germany a series closely parallel
to that of guadalupe, sancarlosense, newberryi, pseudosyrtale, and planum in
this country, all of the European shells present differences showing that
the evolution of the modifications was distinct in France. The gerontic
stages show a greater tendency on the part of the inner lines of nodes to
erow farther out on the lateral zones and approximate to the venter, and
the venter not only flattens out to a plano-convex outline, as in some
American species, but also in a subsequent gerontic substage, as in
P. grossouvrei and milleri, becomes more or less concave. This is due to
the increasing size of the tubercles of the median line on the borders
of the venter after the disappearance of the ventral lines of earlier stages.
Kossmat® sums up the literature of the genus Placenticeras and its
allies. The type of the genus Buchiceras is erroneously considered as a
species of Schloenbachia. Schloenbachia is a genus with normal outlines to
the sutures, a decisive keel with channels or smooth bands on either side,
and more or less sigmoidal, prominent, well-developed cost, the aperture
having a long, pointed rostrum correlating with the keeled venter. The
development is also very distinct from that of any of the Pseudoceratites of
the Cretaceous. In preceding pages, Bb. bilobatwm is joined with other
related species, and the differences of the series to which it belongs can be
more readily seen. Kossmat’s strictures with regard to my own work on
this group are just and most of bis objections well founded. His reference
to balduri Keyserling, as the probable radical of Placenticeras may be
correct. At any rate there are some facts that favor this. The sutures
are similar to those of Placenticeras. The young of this species certainly
So
aSiidind. Kreidef.: Beitr. Pal. und Geol. Osterreich-Ungarns und des Orients, Vol. IX, 1895, p. 171.
192 PSEUDOCERATITES OF THE CRETACEOUS.
:
resembles that of some of this genus in having a channeled venter, but
it is much too involute and compressed for a primitive type. The keel
of balduri is developed in the center of a broad, concave venter of neanic
age, as an obtuse raised area, but finally the entire venter becomes
elevated with a subacute carina, like that of Buchiceras. A raised nascent
keel may be said to appear at a late age in some species of Placenticeras,
but the venters in them are very narrow, and no such effect is produced
as in balduri. The very narrow channel of the ananeanic stage in this
species and the late development of the tubercles produce resemblances
to Diplacmoceras, but in this genus the outer lines of tubercles are not on
the ridges of the venter as they are in balduri. Tf this species is the
ancestor of Diplacmoceras, we have still to account for this and the fact
that the nepionie stages in Placenticeras exactly match those of Protengono-
ceras and Knemiceras and are never keeled as in Buchiceras and Roemeroce-
ras. So far as Keyserling’s drawings go, the nepionic form of baldwri
before the channel appears is like that of Buchiceras and Tissotia serrata.
The separation of the genus Placenticeras from the Hoplitidee* demands
a few words of explanation. Its association with Hoplites by Douvillé and
Grossouvre depends upon the connection supposed to be shown by the
large first lateral saddle of Hoplites splendens. This saddle, as figured by
these two distinguished authorities, has the three large marginal lobes and
three saddles which are supposed by them to be homologous withthe three
principal laterals of Placenticeras.
The author's position is quite distinct from this. If the three marginals
of H. splendens, having undoubtedly, as stated by them, great similarity to
the principal laterals (first to third) of Placenticeras, are intermediate grada-
tions and not a case of parallelism, some similar stage ought to be present
in the development of species having three principal laterals. This, so far
as I know, is not the history of the development in any form of this kind.
a}t is disappointing and much to be regretted that no direct mention is made of Prof. James
Perrin Smith’s paper on The Development and Phyiogeny of Placenticeras (Proc. Cal. Acad. Sci., 3d
series, Geol., Vol. I, pp. 181-240), although incidental reference to it is made in connection with
the development of the sutures. If Professor Hyatt had completed the revision of his manuscript, he
would doubtless have reviewed this paper and made some dispositon of the two species P. pacificuimn
and P. californicum, treated in it. Professor Smith concludes that Placenticeras was derived directly
from Hoplites, but the two species whose ontogeny he studied differ greatly from the typical forms of
Placenticeras, and the results should be tested by a comparative study of some such forms as P. placenta
or whitfieldi.—T. W.S.
PLACENTICERATID®. 193
In all genera having but one principal lateral (Hoplites, Schloenbachia,
Buchiceras), this lateral is a direct and closely connected modification of the
primitive lateral of the young. Also in genera having two or three saddles
these are not preceded by an intermediate stage in which one large lateral
arises like that of Schloenbachia and Hoplites splendens, but on the contrary,
these principal laterals arise through the continuous growth of the two or
three primitive and more or less tongue-shaped and at first entire mar-
ginals that develop in the top of the primitive first lateral lobe, as has lately
been shown by J. Perrin Smith.
When these are arrested in development and do not increase in com-
plexity and remain entire or become simply bifid or trifid, ete., the differen-
tiation between them and the auxiliaries is lost and the sutures of the adult
are similar to those of the Engonoceratidee and the like. When, however,
these do acquire more complex outlines and the development is duly pro-
gressive, its effect is invariably and naturally greater upon the saddles and
lobes of the outer side, which have free growth and are most called upon
to help hold the animal in the shell. These, either on this account or for
some other reason as yet unknown, certainly during development as a rule
become more complex than the inner laterals. This complexity is, asa rule,
less in direct proportion to the distance of the saddle or lobe from the
periphery if an allowance be made for the natural division due to the greater
or less persistence and sometimes more or less independent development of
the largest lateral lobe. This is the primitive first lateral in normal forms,
but in retrogressive genera it may be, as in Placenticeras, the third marginal
lobe of the primitive first lateral, as has also been shown by Smith. This
greater development can be accounted for by the greater stress of the muscles
at these median parts in balancing the shell while crawling. It interferes
with the regularity of the gradations in size and complexity of the series,
and marks the division between the principal or larger lateral lobes and
saddles and the so-called auxiliaries.
In most groups of Ammonitinz the first lateral becomes bifid and the
centran marginal lobe is the first that appears. Usually the next saddle to
become bifid is the first auxiliary. This occurs in Placenticeras, while the
second and third laterals still have entire bases. In other words, similar
laws govern the development of the two series of saddles, the principal
laterals and the auxiliaries, so far as the development of the first saddle of
03—-13
MON XLIV
194 PSEUDOCERATITES OF THE CRETACEOUS. :
each series is concerned. Subsequently, however, there is more irregularity.
Thus the second auxiliary is not necessarily the next to become bifid, but
it is apt to be the next, and the process passes inward, the innermost saddles
being usually the last to become bifid, but there is great irregularity in the
first appearance of bifidity or division among the auxiliaries.
As a rule, however, this irregularity does not occur in the innermost
saddle, which is often broad and remains entire later than its neighbors
and is the last to show complications of outline.
The second and third of the principal saddles in Placenticeras appear
to reverse this law of progress inward. After the first has advanced to the
trifid stage, it is the third which leads in complication of outline and the
second which comes next. This same reversion is found also in the
principal lobes In this genus the primitive lateral lobe is continuous in
development with the third lateral, and it is this that first shows the trifid
division, which is the incipient stage of complication; then the second
follow, and after this the first. The last two, however, may progress in
nearly equal ratio.
The second, third, and fourth auxiliary lobes are apt to follow the
lead of the first auxiliary in regular succession, but there is variation in this
respect, as among the saddles. The general law, however, is the same as
among the saddles, the innermost being the last to modify their entire
primitive outlines. :
In the development of the sutures there are, however, two series to be
considered, first the products of the development of the first primitive
lateral saddle of the nepionic stage, and second the products of the inflec-
tions in outline of the second primitive lateral saddle. These form two
series of lobes and saddles on either side of the primitive first lateral lobe
and obey different laws of development. The complication in the lobes
proceeds from the oldest lobe, the primitive first lateral, outward and
inward; the complication in the saddles begins with the primitive first
lateral and proceeds inward when that saddle is not divided in the neanic
stage. When, however, that saddle is divided into three, there is more or
less irregularity in the progression in complexity of the outlines of the
second and third saddles. The outer division or principal first lateral is,
however, apparently always the one that grows fastest and leads off in
acquiring a more complex outline, as may be observed in about all of the
genera noted below.
PLACENTICERATID®. UNS 5)
The tendency of the saddles to become bifid in their first stage of
complication was noted by Branco and since by Nickles, but in the lobes
this varies. In these the first stage of complication is apt to be either bifid
or trifid, according to the form of the entire lobe of the preceding stage.
If these be pointed, the next step in complexity is the formation of a trifid
top, if they be rounded or flattened, the next grade is usually a bifid
termination.
In the genera described below there is a notable tendency toward the
formation of trifid lobes in all of the outer lobes and in a number of the
auxiliary series, the inner and last auxiliary lobes showing a tendency to
become bifid.
The-saddles and lobes in any one suture of the genera which have
arrested development of the lobes and saddles, and even in some like
Sphenodiscus and Placenticeras with very complex outlines, show a graded
series of modifications from the line of involution outward. These have
frequently such simple entire lobes and saddles near the umbilicus that one
can see at a glance that they are like the entire outer lobes and saddles of
the young. The suture, in fact, presents a series of modified forms that
show in a general way the history of the development of any one of the
outer lobes or saddles, if it be traced from its entire stage to the suture
which is being observed. This is due to the fact noted above and also
shown in Branco’s observations and the author's on the young, viz, that
new lobes and saddles as a rule are added from the line of involution so
that these in any extended suture line are younger or later introductions.
In some genera with arrested development these remain comparatively
unmodified, but in most genera of Ammonitine and in Placenticeras these
do become modified and have complex outlines in later stages, although
never so complex as in the outer saddles and lobes. When this modifica-
tion by development takes place these internal and younger lobes and
saddles proceed or develop by repeating the stages passed through by
their outer and more rapidly developed companions of the same sutures.
In other words, the lobes and sutures of Ammonitinee exhibit the same
law of repetition or parallelism in local development which was. first
discovered by Dr. R. T. Jackson among the Echinoids. He there showed
that a newly introduced plate of the corona passed through stages of
modification in the course of its subsequent growth which were parallel
196 PSEUDOCERATITES OF THE CRETACEOUS. .
with those which had already been passed through by the surrounding
plates of the corona during the stages of the ontogeny.
In other words, there is a local ontogeny in newly introduced lobes
and saddles parallel with the developmental ontogeny of the same elements,
and, in growing, each newly introduced internal lobe or saddle repeats
locally the same stages of development. The arrest of development, which
takes place habitually in all forms of Ammonitinz, internally stops the
progress of each lobe and saddle at different stages in proportion to the
distance of the lobe or saddle of the auxiliary series from the line of involu-
tion. In genera like Hngonoceras, however, the entire suture is arrested in
development and presents therefore a certain resemblance to the young of
other Ammonitinze in the neanic stage and especially to the young of
Placenticeras after the three entire principal lobes and saddles and the entire
lobes and saddles of the auxiliary series have appeared. It may be objected
that the division between the species is too minute and artificial, and it is
admitted that this objection is in one sense well founded.
There is no real line between P. guadalupe, sancarlosense, and planum,
nor between newberryi and guadalupe, nor between guadalupe, sancarlosense,
syrtale, intercalare, and placenta, nor between intercalare, stantoni, pseudopla-
centa, and whitfieldi. As a matter of fact there is no real break, such as is
usually supposed to establish a species, between P. guadalupe and the
extreme form of whitfieldi. ‘
If, however, one admits that all American forms make up only one
species, it becomes illogical to separate the European forms from each
other or the American from them, and, consequently, all the forms of
Placenticeras are one species.
I have not been able to find any middle ground between these two
extremes, but have found that it is possible to diagnose species by describing
the normal forms, meaning thereby the shells that are most distinct and
usually most numerous in each species, and adding thereto the mention of
intermediate forms.
When this is done, it is seen that in this genus the separable forms or
species can be distinguished by their differences in development of the
sutures, of identical ornaments, and of the sectional outlines of the volutions.
The changes that take place in the aspect of the venter and of all characters
in the senile or gerontic stage are included under the term development,
which in the sense here used means all the modifications of the ontogeny.
PLACENTICERATID Bb. NSIT
PLACENTICERAS GUADALUP®" (Roemer).
Pl. XXIX, figs. 1-4.
Ammonites guadalupe Roemer, 1852, Kreideb. v. Texas, pl. 2.
The best specimen I have seen has a diameter of about 145mm. Outer
volution on gerontic living chamber about halfway to the aperture is 63
mm. and transverse diameter 47 mm., the same volution opposite is 43 mm.,
the transverse being 34 mm., avoiding the tubercles. The umbilici are
deeper, the umbilical zones being more rounded and the involution greater
than in pseudosyrtale. ‘Vhe involution covers the inner volutions to the inner
line of tubercles, whereas in pseudosyrtale these are not only completely
uncovered but well inside of the line of involution, The venter is very
broad, so that the second lines of tubercles are on its lateral angles and the
first lateral saddles and lobes are on the ventral aspect. The alternating
ventral tubercles and the flat ventral zone between them are retained on the
venter throughout the ephebic stage. The inner row consists of large
acute spines, solid at the tips only, which are large nodes on the cast, at
the start when the umbilicus is only 25 mm. in diameter. These recede
outwardly with age, but remain more prominent than in pseudosyrtale at the
same age and the inner ridges are also much larger. The aperture is
partly preserved and is apparently at the end of the metagerontic substage,
judging by the last sutures, which are not closely approximated, and by
the aspect of the last tubercles. The margin of the aperture has a sinus
near the line of involution and broad lateral crest, but beyond this it could
not be seen. The venter is convex and elevated in the gerontic stage and
had a ventral zone as described above. The volutions are stouter at all
stages than in psewdosyrtale. Having broken open this specimen, it was
ascertained, as I had expected, that the young is more compressed and
slender than the outer volutions, although in most Ammonitinee the reverse
of this is true. The rounded nepionie volutions were followed as in other
“Mr. T. W. Stanton has courteously commented as follows upon this species:
“The original spelling ‘guadalupze’ should be restored. The name of the river is ‘Guadalupe.’
The type locality should be given ‘Waterfall of the Guadalupe below New Braunfels’ where the only
horizons represented are the top of the Austin limestone and the lower part of the Taylor beds. The
specimens from San Carlos are from beds probably of about the same age in a formation to which Mr.
Hill has given the local name San Carlos beds. The Fort Worth locality [alluding to the specimen
with that locality in my collection] must be inaccurate, as there are no Upper Cretaceous beds within
several miles of that place.”’
198 PSEUDOCERATITES OF THE CRETACEOUS. ;
species by the compressed and deeply involute volutions of the neanic
stage, and these acquired first the flattened venter and helmet-shaped
section and then, as the ventro-dorsal diameters lengthened, the hollow
venter bordered by smooth ridges and general aspect of Protengonoceras.
The facts were ascertained by excavation as well as by studying the section.
Unluckily the sutures were nowhere exposed in these imner volutions.
The auxiliaries were visible later in the neanic stage after the volutions
had become more compressed. They were then of the syrtale type, but
their simple outlines showed that in the preceding Protengonoceras age they
must have been very simple in outline and perhaps similar to those of
Engonoceras. he nodes on the cast did not begin to appear on the
umbilical shoulders until the shell was about 35 to 40 mm. in diameter and
had entered upon the ephebie stage. The outer row of spines were not
visible until later, and the age at which they appeared, except that it was
later than the neanic stage, could not be ascertained. The ephebie stage
has a stout volution with gibbous sides with proportions entirely different
from those of the gerontic stage. At diameter of 26 mm. from line of
involution to venter the transverse diameter at umbilical shoulders is 15 mm.
and at 6 mm. distant from the venter the transverse diameter is11mm. ‘The
lateral zones are nearly flat and only slightly convergent and then converge
rapidly but convexly to the venter which is broad, being here 5 mm.
The last part of the neanic stage is 11.5 by 5 mm. at the tmbilical
shoulders and the convergence of the faintly convex lateral zones outwardly
is constant to the venter, which is 1.5 mm. in breadth. The gerontic volu-
tion on same section is 45.5 by 35.5 mm. at the umbilical shoulders and
between tubercles; the plano convex venter is 27.5 mm., also between
tubercles. The ventral line of tubercles and the concave area or ventral
zone disappears in the gerontic stage, and the last measurements were taken
after their disappearance near the basal sutures of the living chamber.
Roemer’s figures are excellent, but they show a specimen much larger
than mine, and but just entering the anagerontic substage. Roemer esti-
mated that his shell, when complete, must have been a foot in diameter.
The living chamber of Roemer’s specimen was broken away, or it
would have shown similar gerontic characters. There is a centran trace on
the venter of Roemer’s figure which is present also on the venter of the
ephebic stage in my cast. The trace is double, consisting of a taint depres-
PLACENTICERATID. 199
sion between equally faint ridges. There is also a faint trace on the venter
of the neanic stage, but it is then a single line sunk in the surface of the
shell. It is too faint to be visible in any section, and is probably not present
in the younger stages.
In the neanie stage the rather large siphuncle is at a perceptible distance
from the shell of the venter, but in the ephebic stage it is directly against
it, and the double trace may be due to this.
The sutures are more widely separated in Roemer’s figure than in my
specimen, but this may be due to more vigorous growth. There were
eleven saddles and ten lobes on the older sutures, with less complicated
outlines than in pseudosyrtale, but otherwise similar. The sutures are well
separated at all stages, but the last two are nearer together than the preced-
ing. The ventral lobes are deeper and narrower and the siphonal saddles
more prominent and distinct than in other species, except that described
by Choffat in Portugal as P. whligi. It stands between this primitive form
and P. pseudosyrtale and other American species, all of which have very
broad ventral lobes and less prominent siphonal saddles.
A very fine suite of this species was collected by Stanton and Vaughan,
locality 1467, United States Geological Survey, San Carlos, Presidio
County, Tex. The largest specimen is 204 mm. in diameter; a part of the
aperture at the umbilical zone shows on one side and the length of the liv-
ing chamber is somewhat less than one-half of a volution. The gerontic
stage is present and the involution is considerably decreased along the outer
sides of the nodes on their retreat from the umbilicus. The venter becomes
broader and rounded on the last part of outer volution. The outer nodes
change from round spines to elongated costa, dichotomous with the inner
line of nodes that are nearly at the middle of the lateral zones at this age.
There are some more compressed specimens that still, however, have
very stout volutions and a prolonged stage, during which the venter becomes
broadened and occupies the space between the second rows of nodes, the
outer ventral rows forming lines on either side of a zone occupying the
center of the ventral surface. These features are still like those of typical
guadalupe, but in other cases it is impossible to say whether the specimens
belong to typical guadalupe or to the next described species.
Locality: San Carlos, Presidio County, Tex.
Age: San Carlos beds, Upper Cretaceous.
200 PSEUDOCERATITES OF THE CRETACEOUS. ‘
PLACENTICERAS SANCARLOSENSE 0D. sp. Hyatt.
Pl. XXX, figs. 1-3; Pl. XXX, figs. 1, 2.
5
This is represented by a series of specimens in collections made by
Stanton and Vaughan that fade into true guadalupe.
The typical forms differ in having smaller tubercles, the compressed
stage is more prolonged and the ephebic volutions are never so stout nor
the venter so broad as in guadalupe. The stage in which the venter is
broad and bounded by the second line of nodes and similar to that of
guadalupe is short and is often distinctly confined to the anagerontic
substage. Some of the specimens of this form are very closely similar to
P. syrtale. This last species has, however, so far as known, no stage in
which the venter resembles that of guadalupe, i. e., in which the venter
becomes broadened out while the ventral lines of tubercles and the lateral
nodes are still preserved in nearly their full development. This form is
obviously an exact parallel with the P. pseudosyrtale said to be found at
Fort Worth, but from this it is separable by the involution which is more
considerable and follows the inner line of tubercles. There are dwarfs
belonging to this species which have more pronounced tuberculations than
Placenticeras newberryi, bat these approximate very closely to the specimens
from Presidio del Norte, and show that these last are really another grade
of modifications having the same general tendency. ;
Locality: San Carlos, Presidio County, Tex.
Age: San Carlos beds, Upper Cretaceous.
PLACENTICERAS SANCARLOSENSE variety PSEUDOSYRTALE Hyatt.
JAE D-O-O-0UI8 Jel, SOcOS 00K, ies; ah,
The type of this variety is a well-preserved cast 200 mm. in whole
diameter. The last volution from lines of involution to venter, although
much affected by senile contraction, is 80 mm, and the same volution oppo-
site is 65 mm. The ventro-dorsal diameter is 73 mm. about half way the
length of the living chamber, and the transverse diameter is 53 mm., avoiding
the tubercles. The same ventro-dorsal diameter at last septum, taken
always from line of involution to venter, is 63 mm. and the transverse,
avoiding the tubercles, is 43 mm. The tubercles of first inner row alternate
a@See note on p. 202.
PLACENTICERATID®. 201
with those of the opposite side; the outer row is more numerous than the
inner, and there are slight indications of bifureated ridges of costa con-
necting them on the cast. The ventral tubercles are irregularly alternate
with the second row and there may have been ridges bifureating more or
less between these, but there are no indications of these on the cast.
It is very like Morton’s species, but the gerontic stage begins later and
the increase of the ventro-dorsal diameters is much more rapid. The width
through the umbilical shoulders is greater at the same age and the lateral
zones flatter and more convergent, owing to the greater prominence of the
umbilical shoulders. The ventral lines of tubercles are more elongated,
not so close together, and quite different, and the second inner line of tuber-
cles is less prominent and nearer to the vertical lines. The inner lines ot
tubercles do not appear until the ephebic stage and are at first very minute
but rapidly enlarge in the remainder of the ephebic and gerontic stage,
disappearing suddenly before the outer ones at the beginning of the para-
gerontic substage. They recede from the umbilical shoulders outwardly in
the parephebic and gerontic stages and have an inner costation or ridge
inclined apicad.
The outer line of tubercles disappears in the paragerontic substage
immediately after the inner line. The ventral lines of tubercles disappear
on the cast in the metagerontic substage. These tubercles are present on a
bit of the thick ventral shell in the ephebic stage. These are almost linear,
alternating and widely separated, and border a slightly coneave ventral
zone, which is, however, flat upon the cast at the same age. The ventral
zone coutinues well defined and flat upon this cast until quite close to the
aperture in the extreme of the paragerontic substage. The contraction of
the gerontic volution is very marked, beginning, even in the parephebic
substage, before the gerontic septa appear and apicad of the base of the
gerontic living chamber.
The sutures have the aspect of those of syrtale, but the outlines are
more complex and the third lateral lobes longer and more pointed.
This does not appear to be due to greater age, but correlates with
the larger size and other differences in the form and development of this
specimen. There are eleven lobes and twelve saddles on each side in ana-
gerontic septa; the innermost saddle is narrow and apparently entire, all
the remainder divided and bifureate except the first laterals. In these the
202 PSEUDOCERATITES OF THE CRETACEOUS.
inner arm extends inwardly and, being itself bifurcated, gives a trifurcated
aspect to each of these saddles. The inner lobes are bifurcated and
broaden outwardly, being somewhat blunt or rounded except in the third
lateral, which is pointed and apparently of the bifurcated type, as are also
the other lobes. The last four sutures are more or less approximated, and
the last two and part of the third interfere, as in P. placenta, except near and
on the venter.
The living chamber is one-half of a volution in length. The outer
part of the aperture is preserved, showing a blunt, broad, rounded ventral
crest, or slight rostrum, ventro-lateral sinuses on the second line of
tubercles, and the appearances indicate broad lateral crests, but the margins
were broken away inside of this. The approximation to P. sancarlosense is
so close that probably most paleontologists will prefer to consider them
identical, but the lateral nodes are larger and more quickly developed and
the ventral tubercles more elongated and more widely separated. The
extremely thick shell is shown as well as the fact that the ventral tubercles
are not more prominent on the thick shell than they are on the cast.
Locality: Fort Worth, Tex."
Age: Probably same as guadalupe and sancarlosense.
PLACENTICERAS PLANUM nh. sp. Hyatt.
Pl. XX XIII, figs. 2-4; Pl. XXXIV.
This is also a part of the collection made by Stanton and Vaughan.
This species also grades into P. sancarlosense although very distinct from
guadalupe. he sides are almost smooth, the tubercles being very small
and obscure, except in the umbilicus. The affinities for guadalupe and. its
allies are demonstrated by Mr. Stanton’s care in collecting this fine series.
The flat, compressed aspect of the young is maintained until the shells reach
a diameter of 221 mm., and the venter does not show any broadening out
until after the shell reaches the gerontic stage.
One of the specimens from Presidio del Norte, No. 21651, is 240 mm. in
diameter. Four-fifths of the outer volution is in the gerontic stage, but the
first part of the parephebie substage shows the venter still narrow, flat, and
tubereulated. It then becomes rounded, but the volution still remains com-
“Mr. Stanton has commented as follows upon this alleged locality: ‘‘ P. sancarlosense var.
pseudosyrtale, labeled ‘Fort Worth, Texas,’ must have come from some other place, though possibly
in that region.’’ (See note on P. guadalupz. )
PLACENTICERATID®. 203
pressed. There are small tubercles in the umbilicus but these disappear in
the older stages, and almost the entire outer volution is smooth. The other
specimen has similar characters, and the sutures are of the guadalupe and
syrtale type.
This species is not separable in some varieties from P. newberryi, except
by the absence of large lateral nodes at all stages.
Locality: San Carlos, Presidio County, Tex.; Presidio del Norte,
Mexico.
Age: San Carlos beds, Upper Cretaceous.
PLACENTICERAS NEWBERRY! n. sp. Hyatt.
Pl. XXXI, figs. 3-5.
The type is a cast with small patches of shell. Diameter is 120 mm.,
to which must be added perhaps 5 mm. for depression of outer volution.
The diameter of the whole coil one-fourth of a volution younger and not
altered by depression is 94 mm. The outer volution at aperture is 54 mm.
and. transverse is 39 mm., the umbilicus is 24 mm. and the opposite part of
same volution is 42 mm. and transverse 28 mm. The last volution begins
with transverse diameter of 19 mm., enlarges in the next quarter of a
volution to 28 mm., and just beyond this the large gerontic tubercles begin.
The transverse diameter continues to increase until the last quarter apicad
of the aperture is reached, and then it diminishes between the two last
tubercles, which are widely separated, and still further diminution takes place
at the aperture. In another specimen there is no diminution in the rate of
growth of the transverse diameter apparent to the eye, but this specimen
has not a complete living chamber. The almost scaphitean aspect of the
living chamber in some specimens is misleading and is in part due to
depression. Nevertheless, this only exaggerates the gerontic metamorphoses
of this interesting species. Small nodes are present in an early ephebic
substage on the umbilical shoulders and continue to increase, becoming
very large suddenly in the anagerontic substage. Elongated tubercles are
present on either side of the venter in the ephebic stage, but the age of
introduction was not ascertained; apparently it is later than that of the
tubercles on the umbilical shoulders.
The latter are widely separated at all stages, but the ventral tubercles
are close together. There are very obscure fold-like coste, some of them
204 PSEUDOCERATITES OF THE CRETACEOUS. :
dichotomous, on the outer part of the outer volution on the east, but these
have no perceptible middle row of tubercles in the ephebic stage. The
venter increases in the gerontic stage, from being 5 mm. wide between the
lines of tubercles to 20 mm. on the first half of the outer volution, and this
continues to grow broader and more convex until near the aperture, where
there is an apparent diminution. As the venter broadens, the coste are
brought to the edges of the venter and their terminations become enlarged
into rows of nodes as the gerontic stage progresses, but disappear in the
paragerontic substage as the venter broadens and the surface of this
becomes smooth on the casts.
The living chamber is somewhat less than one-half of a volution in
length. It has very deep sinuses on the umbilical zones and prominent
lateral crests. The form of the ventral margin was not seen. The
umbilicus is deep, the internal volution visible, the umbilical shoulders are
prominent, and the umbilical zones are steep and broad, as in other species
of this genus, from a comparatively early age.
The sutures are of the guadalupzan syrtale type and well separated,
becoming approximated only in extreme age. There is only one change,
however, of considerable interest in the gerontic stage due to the broaden-
ing out of the venter. The ventral lobe does not broaden in the same
proportion, and consequently in this stage the first pairs of saddles and
finally first lateral lobes become included within the outer line of tubercles,
thus becoming transferred to the venter, as in P. guadalupe. Another
specimen (No. 11975 a) from the same locality is more compressed, has
somewhat less prominent tubercles, and not so deep umbilicus. In the
interior of the type specimen the venter of the later part of neanic
stage with shell on is exposed. This shows the usual compressed form
of this stage in other species of this genus, the venter narrow, smooth,
concave, as in Protengonoceras, and the volution also resembling that of
that species, but at this time it is of course more discoidal. The largest
specimen of the more compressed variety reaches a diameter of 134 mm.
through the base of a living chamber and when complete must have been
considerably larger.
[have separated newberryi trom P. planwn after some hesitation, because
of the entire absence of the peculiar tuberculated zone of guadalupe on
the broadened venter of the gerontic stage, the more obscure tubercula-
tions, and the more compressed young. The second row of nodes is more
PLACENTICERATID. 205
persistent in the type specimen than in other fossils, and this may be a
specific character, although the condition of other casts does not enable
me to determine this.
Locality: Presidio del Norte, Chihuahua, Mexico.
Age: Probably same as guadalupe.
PLACENTICERAS SYRTALE (Morton).
Pl. XXVIL, figs. 15-17; Pl. XXVIII, figs. 1-6.
Ammonites syrtalis Morton, 1834, Synop. Organic Remains, pl. 16.
Morton’s original specimen is probably a dwarf. At any rate, the
shell is in its anagerontic substage, and the large nodes given in Morton’s
figure belong to this age. The diameter is 75 mm., and it is consequently
smaller than the specimen of var. halei below described; nevertheless the
gerontic stage has begun, as is shown by the great enlargement of the last
pair of tubercles and the depression of the venter, and there is no living
chamber. When. this was present, the diameter was probably about the
same as in the Alabama specimen. The tubercles appear earlier than in
var. halei and are larger at the same age.
A specimen from Fort Worth, which shows the typical characters of
the figure given by Morton, is 97 mm. in diameter. The outer volution is
42 mm. from line of involution to venter and the opposite is 31 mm. The
large size of the umbilicus is due to the recession of the outer volution,
which is in its metagerontic substage, and the shell consequently was almost
wholly outgrown. It has the large inner nodes, and as these are not so
numerous as the next outer row of smaller ones there is a distinct aspect
of bifurcation in the fold-like costz that here and there connect them
throughout the ephebic and gerontic stages. The venter has a narrow,
concave zone bordered by elongated tubercles forming a crenulated border
on either side in the ephebic stage. These are more closely set than in
var. halei from Alabama. The inner row of nodes, as in P. intercalare,
does not hold to the line of the umbilical shoulder, but recedes outwardly
in the gerontic stage, and this stage comes in much earlier than in intercalare
in all of these specimens.
The venter has become rounded on the outer quarter of the last
volution, the ventral line of tubercles being lost. The lateral nodes,
however, remain prominent, showing that the last or paragerontic substage
of senile development has not been reached. The outer row is nearer to
206 PSEUDOCERATITES OF THE CRETACEOUS. .
the venter at all ages than in P. intercalare, and the volutions are stouter in
all specimens of the latter that approximate in their markings to this
species.
The sutures of syrtale at the same age as that given by Meek (Invert.
Pal., p. 471) have the same broad first lateral saddles, but the other saddles
are not so wide as those figured. There are, however, the same number,
viz, 10. They are all minutely digitate except the tenth, which is entire.
The living chamber is fully one-half of a volution in length, and part of the
aperture preserved shows a broad, blunt lateral crest.
This form is obviously very similar to P. intercalare and may be, if
one chooses, considered on one side to be identical with P. sancarlosense
and on the other with P. intercalare. From the former it can be separated
by the venter, which is not so broad at any stage, and by the early
disappearance of the ventral tubercles in the gerontic stage, and the fact
that the venter becomes rounded only in extreme age and is never flattened
as in newberryi and its close ally, sancarlosense.
It can also be separated from intercalare, but the characters are more
dubious. It is certainly so close that the differences in the specimens so
far known might be considered as due to the same causes that dwarfed the
stature of the shells. The young, however, appear to be more compressed
at the same age in syrtale.
Locality: Greene County, Ala.; Fort Worth, Tex. ?
Age: Probably Taylor marls or Austin limestone, Upper Cretaceous.”
PLACENTICERAS SYRTALE var. HALEI Hyatt.
Pl. X XVII, figs. 16, 17; Pl. XXVIII, figs. 3-6.
This is found in the Hale collection (Boston Society Natural History,
No. 8577), and approximates to polyopsis of Dujardin. It has, however,
much heavier lateral nodes and costz in the gerontic stage. The young
in the later neanic stage, judging from the fragment studied, can hardly be
«Mr. Stanton has most obligingly written as follows:
“Locality: ‘Fort Worth, Tex.’ It is not at all probable that the specimen came from Fort
Worth, though it may have been found some miles east of there.
‘“ Age: Upper Cretaceous, probably Taylor marls or Austin limestone.
** Placenticeras syrtale var. halei Hyatt.
“Locality: Greene County, Ala.
‘“Age: This specimen is probably from the Eutaw beds, which are probably very near the
horizon of P. guadalupex, in Texas.”’
PLACENTICERATIDE. 207
separated from the young of P. bolli, although the tubercles of the inner line
are less prominent at diameter of 45 mm., the volution being 23 mm. and
ereatest transverse diameter 11 mm. When the volution is 43 mm. from
lines of involution to venter in same cast, the nodes in both lateral lines
are very large and the ventral tubercles large, the ventral zone becoming
sinuous on the cast in consequence of their size and arrangement. The
venter also begins to show rotundity immediately after this, thus introducing
the gerontic stage; the lateral zones begin to lose their flattened aspect,
becoming more convex, the umbilical shoulders becoming correlatively
rounded. The inner lines of nodes in this species are also apt to be elon-
gated into ridges directed apically, as in polyopsis Dujardin. In _ the
parephebic substage the volution from line of involution to venter in cast is
41 mm., transverse diameter between nodes, which are not close to umbilical
lines of involution, as in earlier stages, but about 14 mm. distant, is 26 mm.,
and through the nodes, which are probably somewhat worn down, it is
30mm. Ina more complete cast of 90 mm. in whole diameter, which has
lost a trifle on the venter by weathering, the same rounding of the venter
begins when the volution reaches about 32 mm. in ventro-dorsal diameter
from lines of involution to venter. The nodes enlarge rapidly in the
parephebic and gerontic stage of these two specimens, and fold-like coste
appear which are obscurely bifurcated at the inner line of tubercles. The
inner nodes are elongated, and have heavy, although not very prominent,
folds on the umbilical zones which bend sharply apicad. The ventral zone
gives place to a rounded area, as in the above, and the inner nodes are
about 10 mm. distant from lines of involution instead of being only a few
millimeters removed, as in earlier stages. They are, however, still on the
umbilical shoulders, and, therefore, in same position as in the young with
relation to the sides.
Locality: Greene County ?, Alabama.
Age: Eutaw beds, Upper Cretaceous.
PLACENTICERAS INTERCALARE Meek.
Pls. XXXV-XXXVI; Pl. XXXVIII, fig. 1.
Placenticeras placenta var. intercalare, Meek, 1876, Mon. U. 5. Geol. Surv. Terr.,
Vol. IX, pl. 23.
This was identified by Meek. with placenta, but its characteristics were
fully given by him and its relations to Ammonites syrtalis of Morton and
208 PSEUDOCERATITES OF THE CRETACEOUS. ;
the true placenta correctly defined. In some parts of his text he also
speaks of this as ‘‘ Placenticeras intercalare,” so that he is the sole authority
for the combined names as used in this description.
The ventral lobe as figured by Meek is very distinet from that of P.
whitfieldi, as are also the entire sutures. This lobe is narrower, the
branches are of the syrtale type, the siphonal saddle is more elevated, nar-
rower, and is subdivided by a median marginal lobe with a minute bifid
saddle; but these distinctions, except in a general sense, do not hold, since
there are the same types of siphonal saddles in whitfeldi. The drawings
by Meek, when compared with the originals, are accurate. The specimen
on plate 23 is in the ephebic stage. The sutures overlap as much as in
whitfieldi. A specimen having external shell in part preserved, from near
Black Hills, South Dakota (purchased from Professor Ward), is 208 mm. in
diameter. The last part of outer volution from lines of involution to venter
is 112 mm., the first of the same being 50 mm. The greatest transverse
diameter of the volution when it is 95 mm. is 44 mm., and when 50 mm. it
is 29 mm. The volution is somewhat stouter than in whitfieldi and the
involution somewhat less. The venter is a little broader and is bordered
by two rows of tubercles of good size. These tubercles quite suddenly
show decrease in size, and become much nearer at the same time on the
last of third and on fourth quarter of this volution. They are present on
both east and shell. On the last part of outer volution they are almost
obsolescent. On the first part of the living chamber they are opposite,
then become again alternate, and as they decrease in size are again opposite.
The ridges on the venter are slight, except in one short space, where
they first become opposite. The shell has numerous bands of growth.
The chevrons are particularly prominent on last part of this volution and
run into and form several longitudinal ridges on the outer half of lateral
zone, while the coste are represented only by very broad, hardly
perceptible, folds. The tubercles of the middle line ‘are of good size and
become obsolete on the last quarter, changing at the same time with
ventral rows of tubercles. Large tubercles are present on the umbilical
shoulders, which sensibly décrease at the same time and also recede
eradually from the shoulders outwardly. These nodes are elongated,
forming parts of the coste that are more perceptible in their neighbor-
hood. The outlines of the ventral zone are not sinuous between tubercles.
PLACENTICERATID®. 209
There is a thick, opaque, horn-colored outer layer, an intermediate
crimson-red layer, and an inner nacreous layer of the usual color. These
consist of a number of minor layers as in other shells of this genus. The
sutures have broader lobes and narrower saddles than in whitfieldi and
placenta, and the outlines of these are somewhat less complicated and not
so overlapping. The ventral lobe has the same narrow character and
syrtale-like branches, with large siphonal saddle, as in Meek’s figure of
P. intercalare, but the siphonal saddle is smooth and entire on the venter,
as in P. whitfieldi, and also has the same minute marginal saddles on either
side of this entire center. A fine young specimen of this species, from
Sage Creek, South Dakota, No. 2104b in collection of Yale Museum, at
diameter of 80 mm., shows the beginning of the large tubercles of umbilical
shoulder, the ventral tubercles, and apparently those of the middle row to
be on the first quarter of its outer volution. This shell must have been
smooth and similar to P. placenta, perhaps, even in the sutures, when the
diameter from line of involution to venter was about 15 mm. At later
stages the sutures are distinct. Another specimen, same locality and
collection, at diameter of 132 mm., shows three rows of tubercles distinctly
visible on both east and shell, No. 2104a. The median lateral lines of
tubercles disappear on the last quarter of the outer volution in this
specimen, but the ventral inner rows persist. As long as the median rows
of tubercles exist the shell has a transverse outline distinct from that of
whitfieldi at any stage, but when these disappear it is difficult to separate
this specimen from whitfieldi. I have not yet seen a specimen in which the
ventral rows of tubercles disappear, but whether they do or not it must be
impracticable in some specimens to separate them from whitfieldi vay.
tuberculatum, although most specimens are distinct on account of the size
and persistence of all of the tubercles.
A fine specimen from same collection from Sage Creek, South Dakota,
(No. 1863) at diameter 144 mm, has already passed well into its gerontic
stage, whereas the specimen figured by Meek is not so far advanced in age.
The first part of the last volution is considerably compressed, as in Meek’s
figure, but on the living chamber on the last half of this volution the whorl
becomes stouter. This chamber is apparently nearer complete and about
one-half of a volution in length. All three lines of tubercles persist and the
ventral ones which are alternate in the ephebic stage are approximately
MON xLIV—03——14
210 PSEUDOCERATITES OF THE CRETACEOUS. ;
opposite in old age and are sometimes connected by a ridge, so that the
venter is serrated. The inner line of tubercles recedes in this stage, as in
specimen figured by Meek.
The sutures have shorter, stouter saddles than those figured by Meek,
and are more like those of P. syrtale. In the first lateral saddles especially
they are more deeply cut into by the lobes that broaden out apicad, and the
other lobes and saddles are like those of intercalare, as figured by Meek.
The resemblances to syrtale occur more markedly in old age, when the
body of the first lateral saddles loses the thread-like tenuity of the ephebic
stage and becomes thicker. All the saddles do not show these changes
equally. This last specimen has enabled me to make connections with No.
18975 U.S. National Museum, from the Upper Missouri, which is a nearer
approach to syrtale. The inner nodes on this last are about the same, but
are not partly buried by the involution and make their appearance some-
what earlier in the neanic stage. The outer line of tubercles are larger and
the venter is broader. The sutures, however, and the proportions, ete., of
the volutions are about the same. Lastly there is a fragment in same
collection, locality No. 1720, 5 miles southeast of Harpers Station, Laramie
Plains, Wyo., that no one would think of separating from syrtale by the
external characters. The diameter is 94 mm., and the specimen has the
same wide umbilicus, stout volutions, prominent nodes, and sharp ventral
tubercles as that species. The sutures, however, although the specimen is
so small, are almost as excessively complicated in outlines as in Meeks
figure, although this was taken from a much larger volution.
One specimen, No. 9735, U. S. National Museum, from Ponil Canyon,
New Mexico, has characters just intermediate between P. intercalare and
P. placenta. The young and full ephebic stage has the form of the stouter
specimens of intercalare with three rows of tubercles. The two outer rows
are, however, more delicate than usual in intercalare, especially the median
lateral ones, which are very small and widely separated as im P. placenta.
Unfortunately the last of the ephebic and the first part of the gerontic
stages are missing, but the parts left show similarity with the old age of
P. placenta and intercalare. The venter does not broaden out except very
slightly while becoming rounded as it does on the third quarter of the
outer volution. The sides lose the abrupt elevated umbilical shoulders and
become evenly convex, but the involution continues to follow the umbilical
PLACENTICERATID ®. fi |
line of tubercles. The ventral lines of tubercles persist on the outer
volution, but are very faint and finally disappear. The same is true of the
other lines of tubercles, all of which finally disappear in the paragerontic
stage. The shells of this species do not apparently have the gerontic
enlargement of tubercles into heavy blunt nodes which is common in
guadalupe. aud its allies, sancarlosense, planum, and also syrtale. The sutures
are like those of syrtale and less complicated than in intercalare at the same
age, but this appearance is probably largely due to the fact that they are
less crowded and do not overlap.
Locality: Black Hills region.
Age: Fort Pierre group, Upper Cretaceous.
PLACENTICERAS PLACENTA (Dekay).
Pl. XX XIX, figs. 3-6; Pl. XL, figs. 1, 2
Ammonites placenta Dekay, 1828, Ann. New York Lye. Nat. Hist., Vol. IT, pl. 5, fig. 2,
not fig. 3.
Placenticeras placenta Meek (pars), 1876, Mon. U.S. Geol. Surv. Terr., Vol. UX,
p- £65.
Placenticeras placenta Whittield (pars), 1892, Mon. U. 8. Geol. Survey, Vol. XVIII,
pls. 40, 41.
This species is represented in the Museum of Comparative Zoology
by a large fragment from New Jersey 101 mm. in diameter from line of
involution to venter at base of living chamber, and this last is about
one-half of a volution in length. It is a cast and smooth on the sides, with
the exception of a line of fold-like tubercles on the depressed umbilical
shoulders. The ventral zone, even at this stage, obviously fully gerontic,
is flat and 7.5 mm. broad as estimated.
The last sutures have not so highly complicated outlines as whitfieldi,
but the lobes are long and narrow, the first and second laterals highly
inclined apically. The fourth lateral is about two-thirds as long or only
slightly shorter than the third lateral lobe. The saddles are not so deeply
divided as in whitfieldi and broader and more solid. The last two sutures
are approximated, but the third, although partly preserved, is at the usual
distance and shows that this is not the same as the western form described
by Meek as placenta. The sutures of this large specimen of P. placenta
have exactly the outlines given by Whitfield in his figure, and a similar,
212 PSEUDOCERATITES OF THE CRETACEOUS. :
although perhaps older, siphonal saddle has numerous denticles or marginal
saddles. The median marginal lobe was not quite so plain as in Whitfield’s
figure, but this might have been owing to age or variation in sutures or the
condition of the cast. Meek, as well as Whitfield, included under placenta
several species which are separated in these descriptions, but Whitfield
recognized and described the differences between the western and the New
Jersey specimens and considered them as probably distinct. I have
consequently named the western species whitfieldi im recognition of this
fact.
The specimen described above enables me to add the following: The
venter is not rounded on the smaller end of this cast, but flat, having the
same form as whitfieldi, but broader than in that species; subsequently,
although not well preserved, this part appears to become rounded. This
specimen shows that in extreme age the volution is shorter and has more
gibbous sides than in whitfieldi and shorter ventro-dorsal diameters. The
decrease in involution due to senility is also more marked, and takes place
at a smaller size. This species stands between syrtale and whitfieldi in
this respect and in its sutures and other characters.
There are several fragments in the Hale collection of the Boston
Society of Natural History, supposed to be from Greene County, Alabama,
which have saddles with more solid bodies or basal parts, as in true
placenta These indicate a species of larger size than the associated species
of P. syrtale, having volutions with smooth flat sides and smooth venter,
as in placenta. The sutures agree very closely with those given by
Morton for P. placenta from the cut of the Delaware and Chesapeake Canal,
and one specimen shows a rounded venter. The examination of the fine
suite of original types and specimens in the Museum of the Academy of
Sciences of Philadelphia gave the following results: The septum of this
species is much flatter, having only a very slight double curvature in place
of the very marked double curvature of whitfieldi, and this is less apparent
on the suture line than on the surface of the septum. On a volution 63
mm. from line of involution to venter, transverse diameter is 22 mm. and
there are three lines of tubercles. The lateral row is two-thirds of the
breadth of the sides, nearer the venter than the dorsum, and very small
and widely separated, but still quite distinct. The tubercles on the venter
of placenta are large and elongated like those of bolli and much coarser and
PLACENTICERATID. Prltey
less numerous than in some specimens of whitfieldi. These disappear in
the ephebic stage, together with the lateral line of tubercles, and in some
specimens the latter may be entirely absent as in young specimens figured
by Whitfield. The large originals of Morton’s figure and of Whitfield’s
show these figures to be approximately correct. The venter is in all stages
broader than in true whitfieldi, but remains flat only through a small part
of the gerontic stage. In two specimens, 365 mm. and 425 mm. in diameter,
one Morton’s type, from cut of Delaware and Chesapeake Canal, the living
chamber was. practically complete and about one-half of a volution in
length. The rounding of the venter begins in these on the still separate
part of the second quarter of the outer volution. Near the aperture the
venter is completely rounded and the decrease in the ventro-dorsal diameters
between the lines of involution more marked than in whitfieldi, and the
umbilici are consequently larger. The sutures vary from having very solid-
looking saddles as in Whitfieid’s figure to those with the first to third
saddles almost indistinguishable from those of some varieties of whitfieldi.
Upon the whole, however, it is safe to say that while the saddles of placenta
may be as deeply undercut and the necks as thin as in whitfieldi, the basal
parts are, perhaps, always less completely cut up by the marginals. These
and the auxiliary saddles have, however, as a rule, a bifid aspect with a
large median marginal deeply dividing them, and this seems to be a distine-
tion of more importance, especially in the aspect of the auxiliaries. The
proportions of the diameters are also quite different. In the ephebic stage
the transverse diameter may be more or less than one-third of the diameter
from line of involution to venter and in old age it may be more or less
than one-half of this same diameter. A young specimen of diameter of
about 60 to 65 mm. is in collection of the Academy of Sciences of Phila-
delphia. In the neanic stage this cast had highly compressed smooth
volutions as in whitfieldi, but the umbilicus is larger, the involution being
somewhat less, apparently. The three lines of tubercles begin on the first
part of the outer volution or just before, when the shell is about 45 mm. in
diameter. At this stage the lobes and saddles are distinctly placenticeran.
The saddles are all bifid, but the entire outlines have given place to com-
pletely denticulated outlines over both lobes and saddles, even on the
innermost auxiliaries in the older parts of this cast. The sutures at this
age are very similar to those of syrtale and guadalupe.
214 PSEUDOCERATITES OF THE CRETACEOUS. :
Until a late age this shell is separable from stantoni or pseudoplacenta
by the presence of the minute median lateral line of tubercles. The larger
size and wider separation of the ventral tubercles separate the younger
stages, in which the venter is often very narrow and the sutures similar to
those of whitfieldi, from var. tuberculatum of that species. The sutures,
however, as a rule, have less complex outlines and more solid-bodied saddles
and less concave septa, as stated above.
Locality: New Jersey, Alabama.
Age: Matawan formation (clay marls), Upper Cretaceous.
PLACENTICERAS STANTONI n. sp. Hyatt.
Placenticeras placenta Stanton (pars.), 1894, Bull. U. S$. C20l. Survey No. 106, pl. 39,
figs. 2,3, not fig 1.
Locality: Upper Kanab Valley, Utah.
Age: Colorado epoch, Upper Cretaceous.
PLACENTICERAS STANTONI variety BOLLI Hyatt.
lab oGUp iiesh Bare 1b DObIS IAL OOO JFL IOIOOL, ines, Il, 2.
Placenticeras intercalare Meek (pars.), 1876, Mon. U. 8. Geol. Surv. Terr., Vol. LX,
p. 471.
This species is very like P. placenta and whitfieldi, bat has much stouter
volutions with broader venters at the same age and is intermediate in
character between intercalare and whitfieldi. The coste are of the syrtale
type, but are merely obscure folds on these casts. The tubercles are sparse
and on the umbilical shoulders as in placenta. The costz are occasionally
bifid on the outer part of the side with single ones between them. The
elongated ventral tubercles are alternate and each one has its costation.
The sutures have much shorter lobes and stouter, shorter saddles than in
placenta.
The young in the nepionic stage have a smooth volution with rounded
venter. In the neanic stage this changes through the elevation of the venter.
The ventral zone is at first quite broad comparatively and perfectly flat in
the neanic stage. In the ephebic stage it becomes much narrower and con-
eave and probably then acquires its tubercles. The tubercles on the
umbilical shoulders do not appear until this stage begins.
PLACENTICERATID. 215
The lateral angles of the single costa, and still more the junctions of the
dichotomous costee, when these occur, tend to rise up more prominently
than the rest of the costation as in other forms, but they do not in the
specimens examined, as in syrtale and intercalare, become tuberculose. The
specimens from which these descriptions were taken are in the Museum of
Comparative Zoology.
This species is distinguished from P. placenta by the shorter and stouter
lobes and saddles and the better separation of the sutures at all stages
except, perhaps, the youngest. It stands apparently nearer to P. syrtale
in its sutures than to intercalare, but this is due to the fact that in intercalare
the sutures vary from those like syrtale to as complicated as in Meek’s
figures, and if the comparisons are made with the former, it is seen that the
external characters and sutures place it between infercalare and whitfieldi, on
account of the suppression in both of the lateral line of tubercles. A speci-
men from Dallas County, Tex., has similar markings and sutures so far as
seen on the young volutions, and is probably the gerontie stage of this
species. It is an incomplete living chamber about one-half of a volution in
length, with the inner volutions attached but badly crushed. The latter
shows the large inner row of nodes and the sutures in part, and these last
agree closely with those of the specimen described above.
The volution from line of involution to venter at base of living chamber
is 75 mm. in diameter, transverse diameter about 40 mm., and at one-fourth
of a volution distant from this the diameter is 91mm. The venter is broad,
and the ventral zone convex on the cast at the two last septa. ‘The
tubercles are almost obsolete and the costa completely gone, the cast
being smooth with the exception of one obscure broad longitudinal ridge
on the centran surface of the lateral zone. The remnants of tubercles
are shown in obscure and very slight folds with a decided apical trend.
This description shows that the gerontic stage is quite distinct from that of
placenta or whitfieldi.
The basal suture is very complex in its outlines, but has the short
saddles and lobes of this species. The next younger septum is, however,
closely approximated to the last. The first and second lateral lobes are
very narrow and the saddles approximate. he lateral lobe is also narrow.
The remaining lobes and saddles are more like those of the younger stages,
but also have narrower lobes and broader saddles. These sutures are quite
216 PSEUDOCERATITES OF THE CRETACEOUS. :
distinct from those of other species and come nearer to those of the old
whorl of P. placenta from New Jersey than any other form. They are,
however, smaller, and the apical trend of the outer lobes is less, the third
lateral being shorter, and the remaining lobes more abruptly separated
through their extreme shortening up as compared with the third lateral.
Having received through Professor Martin the specimen described by
Meek from Tarrant County, Tex.,“ as belonging to P. intercalare, | am able
to state that it is a good cast of this species. The diameter is 90 mm.
The living chamber is incomplete but nearly half of a volution in length.
The median lateral line of tubercles is absent, the inner line of small
tubercles recedes from the umbilical shoulder, and the ventral tubercles
are rather coarse and large, and the venter broad as in typical bolli. The
sutures have the solid short saddles and short lobes of this form. The
paraphebic substage is reached near the aperture.
Locality: Elm Fork and West Fork, Dallas County and Tarrant
County, Tex.
Age: “Probably Eagle Ford shales” (Stanton)
PLACENTICERAS PSEUDOPLACENTA Hyatt.
Pl. XLII, figs. 3-11; Pl. XLIV.
Placenticeras placenta (4) Stanton (pars), 1894, Bull. U. S. Geol. Survey No. 106,
pl. 39, fig. 1 (not figs. 2, 3.) :
The sutures are peculiar and unlike those of any of the forms of true
P. placenta or whitfieldi. This fact was noticed by Stanton, who considered
the Colorado species to be different from true placenta. In confirmation of
these remarks I can add the following: A large fragment, U. 8. National
Museum, locality Upper Kanab, Utah, No. 22344, diameter from line of
involution to venter 88 mm., greatest transverse about 35 mm., shows a
wider venter 6 mm. and flatter than in whitfieldi at same age. The side
which is unaffected by pressure is not so evenly convex as in that species,
the outer part being very slightly concave, the centran part slightly
gibbous. The sutures exhibit more complicated outlines than in the
younger stage figured by Stanton, but they have similar ragged outlines
and very broad lobes and are obviously the same. A specimen with
diameter of 385 mm. has on the last volution sutures with same rugged
@Mon. U.S. Geol. Survey Terr., Vol. IX, p. 471.
PLACENTICERATID®. ANU
aspect but very much simpler in outline than those of P. whitfieldi or even
those of true placenta at the same age. The perfect venter at this stage is
concave and it continues smooth and concave in this species until the shell
is much larger, but then becomes flattened and apparently exactly similar
to that of true P. placenta, but is broader at the same age and flatter than
in P. whitfieldi. The sutures are more like those of P. placenta than those of
P. whitfieldi. The casts do not show the shell except in the young stage
and this has obscure sigmoidal bands of growth like those in whitfieldi but
no coste on the shell and none on the casts as is usual in that species.
The youngest stage is more involute than in P. placenta and is like some
specimens of P. whitfieldi in this respect.
Stanton’s figure of the suture was taken from the ephebie volution of
a specimen of the diameter of 173 mm The volutions were perfectly
smooth on this cast, with a flat, broad venter, and at the diameter given on
the third quarter of the outer volution the gerontic stage had begun and
the last part of the volution was helmet-shaped in section with a rounded:
venter. This shows a paragerontic stage earlier than is usual in placenta or
in. whitfieldi.
The specimen alluded to by Stanton, from Ellis County, Tex., Eagle
Ford shales or Fort Benton Group, is a cast 171 mm. in diameter, with
form almost as much compressed, and with thin venter, as in whitfieldi, but
the sutures are more like those of sfantoni. They are, however, more
deeply cut, being older than those figured and more like those of whitfieldi.
In fact, I do not see here nor elsewhere any possibility of drawing
sharp lines, except between the genera; the species all run into one another.
Locality: Upper Kanab, Utah; Huerfano Park, Colorado.
Age: Colorado Epoch, Upper Cretaceous.
PLACENTICERAS PSEUDOPLACENTA variety OCCIDENTALE Hyatt.
Pl. XLV, figs. 1, 2.
The saddles and lobes have the elongated forms of those of P. whit-
fieldi, but are more solid; the ventral lobe has the same elongated arms, and
the ventral saddle is also similar, but the lobes and saddles are simpler and
more like syrtale until a later stage than in P. whitfieldi. The shells have
a row of tubercles on the umbilical shoulders and fine tubercles on the
venter. The principal distinction is, however, the breadth of the venter
218 PSEUDOCERATITES OF THE CRETACEOUS.
and its flatness in the ephebic stage, which is similar to stantoni and
placenta. There are, however, some specimens with smooth venter, as in
whitfieldi. A specimen in the collection of Columbia University, New York
City, No. 10622G, from Upper Missouri River, has a diameter, partly
estimated, of 150 mm. The last volution, with living chamber, is 76 mm.,
partly estimated; the umbilicus is 22 mm., and opposite the same volution,
from line of involution to venter, is 52 mm. The volution is not so flattened
or compressed, having slight ventral tubercles and slightly more gibbous
sides than in whitfieldi, and volutions not so deeply involute, as is shown by
the breadth of the umbilicus. The line of involution is outside the line ot
internal tubercles, and this more open aspect of the umbilicus and the solid
aspect of the saddles and forms of the lobes agree more closely with the
smaller form of placenta figured by Whitfield and are quite distinct from
true whitfieldi of the same size.
The living chamber is incomplete, but occupies about half a volution
in length, and the aperture follows the bands of growth. The siphonal
saddle has several minute denticulations even at this early age Sutures at
diameter of 26 mm., from line of involution to venter, showed distinctly the
syrtale type of outline which occurs in whitfieldi, only at a much earlier
stage, short, broad saddles and corresponding lobes, with well-separated
outlines and no appearance of bands free of sutures on either side of venter.
No. 8238, U.S. National Museum, from Cow Island, Upper Missouri
River, Fort Pierre or Fox Hills Group, is a very interesting fragment of
this form. It is a good-sized fragment, showing the inner and outer volu-
tions, with broad venters and proportions stouter than in typical pseudo-
placenta or whitfieldi. The tubercles on the venter are not large, but quite
plain. They disappear on the last of the outer volution, while the inner
line persist, and there is no median line. There is on the last part of the
outer volution, in the beginning of the gerontic stage, a distinct elevation
along the line usually occupied by the median lateral tubercles, which I
have never seen in whitfieldi, and which usually occurs only in syrtale,
intercalare, and the more heavily tuberculated forms. This is also apparent
in the full ephebic stage, but is less marked. The sutures are very similar
and, in fact, not distinguishable from those of whitfieldi in some varieties.
I have, in consequence, placed this shell under name of pseudopiacenta,
although in general aspect it really seems to agree better with stantoni.
PLACENTICERATID 2. 219
»
One specimen, a fragment given by Dr. R. 'T. Jackson, said to have
come from Bad Lands, near Black Hills, South Dakota, is 73 mm. from the
lines of involution to the venter at small end, and 88 mm. at a distance of
110 mm., measured along the centran axis of the side, or somewhat more
than one-fourth of a volution farther on, the whole length being 160 mm.
This fragment is a living chamber, the last septum and the aperture being
partly preserved. A restoration of the whole coil shows the diameter of the
entire specimen to have been about 174 mm. The obsolescing costee, sparse
and small tubercles on umbilical shoulders, and small, more closely set
tubercles on the edges of the venter, show that this is probably the
parephebie stage of this species.
The venter has become rounded, or rather the previously concave zone
has become convex, but the ventral tubercles, although faint, are clearly
discernible at the oldest end of this fragment.
Thus the gerontic stage must have begun in this species at a size when
the ephebic stage was not yet completed in P. whitfieldi or placenta. The
saddles of the last septum show much less complex outlines than in whitfieldi.
The third lateral lobe was not entirely preserved, but it was obviously not
so long. The outlines resemble approximately those of bolli. Dissecting
out a part of the ephebic volution contained in the zone of involution, the
shell and the sutures also were found perfectly preserved. The probable
diameter of the volution at this age from line of involution across side to
venter was about 35 mm., and the whole diameter of coil perhaps 75 mm.
The shell at the younger end of this fragment, which was about one-fourth
of a volution, showed a decidedly concave venter; the cast was also slightly
concave. At the other end, while the shell was still concave, the cast was
flat on the venter. The tubercles on the younger end were well defined,
but mere fine crenulations, asin P. placenta and whitfieldi. They were barely
perceptible on the cast at this end of the fragment, and not visible at all on
the cast at the other end, although, as stated above, present on the cast of
the gerontic living chamber. The sutures showed somewhat more solid
branches on the saddles than in whitfieldi, and ventral lobes and siphonal
saddles like those of P. intercalare. Previous to cracking out this fragment
the specimen was classified with variety Lolli. The chevron markings on the
nacreous layer were beautifully displayed and very instructive. At the
younger end they had the normal orad direction for about an inch, then
220 PSEUDOCERATITES OF THE CRETACEOUS.
some accident had happened fracturing the edges of the aperture on both
sides and causing a slight sinuous constriction on both sides when growth
was resumed. Beyond this the direction of the chevron lines was reversed
on the right side in a median depression and on the left along a slight
corresponding elevation.
One fragment from Elm Fork, Dallas County, Tex., in the Museum of
Comparative Zoology, not quite one-half of a volution in length and
measuring 230 mm. in diameter, has these characters, but the umbilicus
does not appear to be quite so large in proportion. The aspect of the
saddles enables one to separate these from var. tuberculatum ot P. whitfieldi,
but it is probable that these two are connected. As I have repeatedly
stated elsewhere, I consider this varietal connection no argument for uniting
these obviously distinct species. This specimen has large marginal saddles
on the siphonal saddle, and a distinct marginal median lobe, which becomes
slightly trifid in later stages. On the left side of this are entire slightly
phylliform saddles, and on the right a bifid marginal. These become
subdivided later. The ventral lobe has the long arms of the whitfieldi type
which are not similar to those of the same lobes in the syrtale type.
I propese, in following the indications of these observations, to confine
this name to those forms of this genus having broad venters and more
immature sutures than in whitfieldi at all stages of growth. The edges of
the venter may be either finely tuberculated or smooth. The sides may
be smooth or with a median line of very obscure elevations. The inner
line of tubercles is developed, but does not appear at an early stage.
Locality: Elm Fork, Dallas County, Tex.; Upper Missouri, Bad Lands,
South Dakota.
Age:* Probably Fort Pierre group, Upper Cretaceous.
“The following note has been kindly added by Mr. Stanton:
“* Placenticeras pseudoplacenta var. occidentale Hyatt.
“Tocality: Upper Missouri. Bad Lands, South Dakota.
“Age: Fort Pierre group, Upper Cretaceous.
“The specimen from the Bad Lands is certainly from the Fort Pierre, and the one from the
Upper Missouri probably is also.
“The specimen labeled ‘ P. pseudoplacenta var. occidentale’ and also ‘ var. intermedium’ from Elm
Fork and West Fork (Horton’s mill), Dallas County, Tex., if the locality can be trusted, is probably
from the Eagle Ford shales, which are about equivalent to the Fort Benton.’’ (The locality referred
to is trustworthy.—A. H.)
PLACENTICERATID. 221
PLACENTICERAS WHITFIELDI n. sp. Hyatt.
Pl. XLV, figs. 3-16; Pl. XLVI; Pl. XLVI, figs. 1-4.
Placenticeras placenta Meek (pars), 1876, Mon. U. 8. Geol. Sury. Terr., Vol. UX,
pl. 24, fig. 2.
This species can be distinguished from true P. placenta of New Jersey
and the supposed western members of the same species by the following
characters. The highly compressed volutions are more involute and the
venter is narrower throughout life and less completely rounded in old age,
and this change comes in only at a much larger size than in the shells of
P. placenta. Owing also to the absence of the median lateral line of tuber-
cles the volution has flatter sides. All tubercles are wanting in typical
forms at all stages, but very fine tubercles are present on either border of
the venter and larger ones on the umbilical shoulders in some shells.
Sometimes minute tubercles are present on the median part of the lateral
aspect, but these occur only in the neanic stage, disappearing with the
ventral tubercles in the ephebic stage. The sutures are more complicated
in the young and are more overlapping than in placenta. The saddles are
almost linear because of the excessive development of the lobes, which are
very long and narrow. These differences hold with the materials so far
examined. It must be remembered, however, that as yet no examination
of a large number of specimens of both species from the same locality has
been made, and it is likely that there are intermediate shells. “Certainly no
one can distinguish these species unless familiar with both forms or having
both for comparison. The same may be said of P. intercalare, between
which and this species there are intermediate shells in P. whitfieldi var.
tuberculatum.
I made special examination of the ventral lobes of whitfieldi in all
available specimens. All had the peculiar very broad ventral lobes with
long narrow branches on the lateral aspects except in rare cases in which
syrtale-like or blunter arms were present. One specimen had the long
narrow arm on the right side and a blunt syrtale-like arm on the left side.
As a rule the ventral lobe is symmetrical, but the siphonal saddle is often
unequally developed or out of place. This saddle is often entire and flat, so
that one is apt to regard this as the normal form, but variations are so
frequent that only large numbers of specimens could determine the facts.
222 PSEUDOCERATITES OF THE CRETACEOUS. A
This saddle may have a simple median marginal saddle or be trifid with
three saddles, equal or unequal in size; or it may be bifid, with both mar-
ginals again sul divided, or of any shape between these and such irregular
sinuous outlines that it is difficult to describe it. It is almost invariably
sunken between two marginal saddles, one on either side, but occasionally
even these blend with the central part of the siphonal saddle.
A specimen from Cheyenne River, South Dakota, in the collection of
Columbia University, New York City, reaches 327 mm. in diameter and has
the basal part of a living chamber present. The venter begins to be rounded
on this living chambered part. There is a slight decrease in the amount of
involution at the same time, showing that this is in its gerontic stage. In 11
other specimens, in collection of the Boston Society of Natural History, and
sent me by Ward, ranging in size from 110 mm. in diameter to nearly the
dimensions of the specimen last described, the typical form was observed.
No tubercles were present, and the first lateral saddles were very narrow
and very deeply cut by almost straight and very long marginal lobes and
saddles.
Tn all of these there are chevron marks more or less shown, and the
sutures are similar, with the exception first mentioned. The first three lateral
lobes are not very steeply inclined apicad, and the fourth lateral is nearly
or quite two-thirds as long as the third lateral.
Altogether I have seen perhaps 40 specimens. '
A specimen from South Dakota, in collection of the Boston Society of
Natural History, which is 113 mm. in diameter, shows the coste and the
chevrons, but the costs are quite fold-like. There were no tubercles on
the edges of the ventral zone nor on the umbilical shoulders. The smallest
part of the outer volution was about 30 mm. and the widest part about 60
mm. from line of involution to venter.
Some of the fragments of volutions examined must have belonged to
shells fully 15 inches in diameter, the size of the specimen from New Jersey
figured by Morton as P. placenta, but none of these showed the gerontic
degenerations in the rounding of the venter as in his figure. ‘The wider
separation and the simpler outlines of the sutures found in his figure also
occur only at a comparatively early stage in this species. The ephebic
stage has narrow concave venter on the thick shell and flattened zone on
same area in the cast. The sides are perfectly smooth, with faint sigmoidal,
almost obsolescent, coste.
PLACENTICERATID A, 223
Meek figures a specimen just entering upon the ephebic stage, and
these costa are faintly indicated. It is, in fact, difficult to see them, and
they can be felt better than seen in some specimens. The cost are often
quite linear and distinct on the shell in the neanic stage, but are not present
before or after this stage. The divaricating ridges described and figured
by Meek as lines have been described above as lateral chevrons with the
apices pointing orad and occurring only on the outer thirds of the sides of
the shell. They are very plain on the inner layers of shell and faintly
indicated on the cast and entirely independent of the growth bands. At an
older stage (probably the metephebic substage) than that figured by Meek
they are quite broken or interrupted by the bands of growth on one side
where the nacreous layers are preserved, and on the other, in which part of
the outer layer covers them, they are not visible. They are apparently
characteristic of the neanic and part of the ephebic stage. The venter
retains its flatness until the shell is very large. The sutures are really at
considerable distances from each other, but the saddles are so deep and the
lobes so long and narrow that the external outlines are approximated
except on and near the venter. The first lateral saddles are straight and
narrow, and there is consequently a band on either side of the venter in
easts which is not cut up by intermingling sutures. On breaking down a
specimen sent me by Professor Ward the young at diameter of 11.13 mm.
_ from line of involution to venter had the first four saddles even at this
early stage more slender and more deeply cut by the marginal lobes than in
the specimens supposed to be young of P. placenta of the west at diameter
of 25 mm. The lobes and saddles were also longer and narrower in
proportion, the sutures nearer together, and the branches of the ventral lobe
larger and longer and the ventral saddle with larger marginal lobes at
exactly corresponding ages. The ventral crenulations or tuberculations
are not so persistent as in placenta of the west, since they disappear in all
of these specimens in the ephebie stage.
The incomplete living chamber is about one-half of a volution in
leneth.
The first volution of a specimen in the collection of the Museum of
Comparative Zoology, from Clifford, Nebraska, has a depressed rounded
goniatitic form with a single constriction in this specimen at the end of
the first quarter. The lateral sutures along the sides have the broad lateral
224 PSEUDOCERATITES OF THE CRETACEOUS.
saddles; the others were covered and could not be seen. The only exposed
suture immediately preceding the constriction has entire outlines. he
ventral lobes are moderately deep and straight-sided, with large, undivided
siphonal saddle. The first lateral saddle is rounded and broad, but entirely
upon the venter, as is also the first lateral lobe. The latter is also rounded
and wide at base and not so deep as the ventral lobe. The second lateral is
magnosellarian in outline and reaches.to the small lobe formed on the line
of involution. It is interesting to note that m this highly degenerate ferm
of the Cretaceous the sutures exactly resemble at this age the adults of the
Primordialidee, which have undivided siphonal saddles, and the volution
on section has the semilunar anarcestian form of the nepionic stage in
Ammionitinee.”
Near the end of the first volution the first lateral saddles and also the
magnosellarian saddles have begun to show minute dividing lobes. The
form in section has at the same time changed to helmet shape through the
elevation of the venter. The zone of involution at this age begins to
increase and in the next volution extends over nearly the entire side of
the first whorl. In consequence of the helmet shape and flatness of the
sides the involution, which is about two-thirds, appears to be greater
than at any subsequent stage, whereas it is proportionately less. The
ananeanic substage begins on the second volution. The sides become
flatter, more convergent, and the venter is narrowed and flattened on the
cast and slightly céneave on the shell. In the metaneanic this change is
completed by the rapid increase of the dorso-ventral as compared with the
transverse diameter. The venter still remains quite broad and does not
attain the narrow aspect of the adult until in the latter part of the neanic
stage on the fourth volution. The umbilical zone begins to develop in the
ananeanic substage and steadily increases in breadth and steepness there-
after. The auxiliary lobes and saddles begin to appear in the paranepionie,
and as the volution increases in the ventro-dorsal diameter more of them
are introduced by the further division of the magnosellarian saddle, or
rather what remains of this, in the umbilical zone. The process of division
continues throughout the neanic stage, the additions being made internally
on the umbilical shoulders and zone. They arise as simple indentations
and grow deeper with age, the digitations being introduced gradually by
“The margin of the manuscript bears a large ‘‘?’’ opposite this sentence.—T. W. S.
‘
PLACENTICERATID A. 22
minute inflections of the outlines. The saddles are not so long as to inter-
fere with deciphering the outlines of the lobes until the fourth volution is
reached and the anephebic substage begins. Before this the sutures
resemble more those of P. bolli, having shorter saddles and probably at still
earlier stages they are even more like those of this species, being propor-
tionately shorter and with simpler digitations. There are nine lobes present
on the last quarter of the third volution. The three principal lobes have
their usual proportions, and the ventral lobe is nearly the same as in the
adult, but the siphonal saddle is not so prominent, and the minor saddles
on the sides of this are also much smaller and more nearly of the same size.
There are six lobes on the lateral zone, a seventh on the shoulder, and two
on the umbilical zone. The saddles are all distinctly bifid, except the tenth,
which is not yet differentiated. The lobes are all of the trifurcate type,
except the ninth, which is not fully developed and is single or unsym-
metrical. The lobes and saddles greatly increase in complication of outline
and become larger and larger, but the number remains stationary on the
fifth volution. Meek* figures a very large suture with twelve lobes.
Tubercular elevations make their appearance on the edges of the
ventral zone in the neanic stage, but they are more perceptible to the touch
than to the eye. The widely separated sigmoidal costee are more distinct,
but the deep apical bend is only one-half developed and ends abruptly in
some with a faint tubercle. The ventral part of the bend is apparently
absent on the fourth volution, but subsequently appears more decidedly on
the last quarter of this volution. Internally the oral bend of these costa
is also deficient in the neanic stage, appearing to be better developed in
an ephebic substage. Nevertheless, when one looks at the volution, he is
apt to see only the inner half of the deeper apical bend. The chevron-like
folds are present on the shell in the later neanic substages and may come
in earlier. A line of very faint, hardly perceptible, tubercles appears on
the umbilical shoulder on the fifth volution in an ephebie substage.
I have been as minute in my descriptions as the specimen in hand
permitted, because the presence of these indistinct tubercles and cost in
the neanic and early ephebic substages show, together with the more widely
separated sutures and broader venter, that the young are quite similar to
those of placenta and have also traces of their affinity with the more heavily
aMon. U.S. Geol. Surv. Terr., Vol. IX, p. 466.
03 15
MON XLIV
226 PSEUDOCERATITES OF THE CRETACEOUS.
tuberculated and stouter forms P. bolli. The same characters also show
that these species are not identical, since they are not so strongly developed
at any stage as in other species, and are succeeded by distinct sutures in
the nearly full-grown shells. This study suggests also that the western
species was derived from the eastern form.
A specimen purchased from Professor Ward, locality Bad Lands, near
Black Hills, South Dakota, shows the typical sutures and form of whitfieldi.
The first lateral saddles in the ephebic stage have the usual three nearly
equal marginal saddles and lobes, and there are no tubercles nor any coste
appreciable to the eye at diameter from lines of involution to venter of
101 mm. These sutures, however, have one peculiarity, probably of essen-
tial service to this investigation. In so far as the first two saddles and
lobes are concerned, they are appreciably distinct, the first saddles being
entirely free. The remaining parts of the sutures overlap more or less,
as in almost all of this species. In the anephebic substage, or last of
neanic stage, however, the diameter of volution being 33.5 mm., the coste
are apparent and have the usual form, but are very faint. The chevrons
are especially well shown in the fossil, although not more prominent than
in many other specimens. They were plainly seen on this fragment,
broken out of the larger volution, and there appeared to be some connection
between these at their line of convergence and the indistinct longitudinal
ridge or trace, which is obviously the centran lateral ridge seen’in some
older shells. The sutures are similar to those of the adult at the diameter
of 24 mm. from lines of involution to venter, but they are easily separable
by the eye.
The earlier probably paraneanic substage dissected out from this was
pertect and measured 26.5 mm. in diameter of the coil. The larger end
of the volution in this was 15 mm. from line of involution to venter, and
when the volution was about 11 mm. in same diameter the chevrons and
cost and excessively faint longitudinal ridges began to appear. ‘There
were as many as three of these along the centran lateral aspect of the
volution and shorter but discontinuous ones arising from the chevrons.
These could only be seen by careful and prolonged observation of the
nacreous layer, which was preserved on one side. The sutures were less
crowded than in the young one above described and favorable for obser-
vations at diameter just noted. There were ten lobes in all, including one
PLACENTICERATID. 227
on the line of involution. Six were on the lateral zone, one on the sharply
defined umbilical shoulder, and three on the umbilical zone. The last sad-
dle showed a distinct marginal lobe, the next saddle single, the succeeding
saddles were also bifid and had entire outlines, the fourth had begun to
show marginal digitations, and the remaining saddles were more or less
deeply cut, having approximately the forms of the ephebic stage, but being,
of course, much simpler. The outlines of all of them were free except
those of third and fourth saddles and those of the third lateral lobe. The
umbilical lobe is probably entire, as is the next lobe; the eighth is
symmetrically trifid, the next from its position on the umbilical shoulder is
unsymmetrically trifid, the next lobe on the side is symmetrically trifid
again. The remaining lobes show ephebic division already defined but
simpler than in the adult, and the same is true also of the ventral
lobe and saddle, and the bare spaces on the cast on either side of the
venter would be as conspicuous as in the later stages if the sutures
were as close together. One thing is noticeable in this specimen; the
slightly younger sutures on the same volution are for a time slightly closer
than the succeeding ones, owing to a temporary decrease in the rate of
erowth of the shell. This specimen had sutures quite different from the
sutures of the small specimen above described, in which at the same age
there were approximating and even decidedly overlapping outlines, as in
the adult. The outlines themselves, however, were about the same in both
specimens, so that the differences were merely those of the slower, less
vigorous growth of the forms as compared with that now being described.
At the beginning of this volution, when the diameter from lines of
involution to venter is 7 mm., the umbilical zone is just beginning to be
formed. The ventral saddle at this time is just beginning to show
digitations on its sides, and is broad and large with flat concavity across
the venter. The first lateral saddle is distinctly trifid, the second and third
laterals with club-shaped bases and almost entire, showing only the faintest
possible trace of the median marginal lobe that divides them in the
succeeding sutures; the fourth lateral has this marginal lobe more distinct,
but still very small, and the remaining saddles are entire with somewhat
flattened basal lines.
The arms of the ventral lobe and the tops of the first and second and
third laterals are unsymmetrically trifid, the fourth lateral is just beginning
228 PSEUDOCERATITES OF THE CRETACEOUS. :
to have a median marginal division and is bifid, the remaining lobes being
entire and very small and narrow. The trend of the sutures is about the
same as in adults, but the bend at the fourth lateral saddle is more abrupt,
the fourth lateral lobe being a scant one, about one-half the leneth of the
third lateral. This proportion begins to alter soon after this, and approxi-
mates to that of the adult before the end of this volution. The number of
lobes and saddles is the same; they are simply smaller in size and more
primitive in outline. A very slight amount of exposure acts upon these
sutures and alters the outlines, destroying the marginal lobes and saddles.
At this time, i. e., 7 mm. in diameter, the sutures are somewhat more primi-
tive on the left than on the right side of the volution, an irregularity that
subsequently becomes less noticeable. There is probably nothing abnormal
in this, as it is rare in any animal to find the two sides exactly similar.
The cost begin very early when the volution is about 7 mm. in diameter
from lines of involution to venter.
In the ananeanic substage, when the volution is 4 to 5 mm. in diameter,
the ventral zone is channeled, as in later stages, and sensibly broader in
proportion. The form of the sutures, ete., is the same, but the digitations
are less noticeable. The first lateral saddle on the most perfect side of this
volution is faintly trifid, all the remaining saddles are entire and club-
shaped except the smaller ones beyond the fourth, which are now plainly
seen as mere inflections of the outlines of the magnosellarian saddles. The
arms of the ventral lobe are single, the first and second laterals are beginning
to show trifid tops, while the third is broader and more club shaped, and
shows four nearly equal marginal lobes just begining to appear. ‘The
ventral saddle is broad with concave base, the dependent marginal saddles
being absent. There were nine lobes at this stage, but the ninth on the
line of involution was very minute.
The next break exposed an earlier age in the ananeanic substage on
the first quarter of the same volution. The venter had just become flattened
and the edges of this zone are faintly crenulated on the cast, owing
apparently to the presence of extremely fold-like costae which cross the
venter. These are so indefinite that they were perceived with difficulty.
The sutures are extremely instructive. The ventral lobe is as deep
and as broad as the ventral zone; tne ventral saddle is very small and
divided by a siphonal lobe. The sides of the first lateral saddles are
PLACENTICERATID.®. 229
straight, and on the edges of the ventral zone the bases are entire and
rounded. The first and second lateral lobes and the first, second, and third
lateral saddles appear as inflections on the inner sides of the broad
nepionic first lateral saddles. he third lateral lobes occupy the positions
and are obviously the direct local representatives of the primitive primor-
dialian lateral lobes. A large saddle, the primitive magnosellarian saddle,
occupies the inner part of the sides and two minute marginal lobes and
saddles are apparent on this. The first marginal saddle, the forerunner
of the fourth and fifth saddles, is flat on the base and beginning to show
an initial median marginal lobe; the future fourth lateral lobe, the inner
saddle, has similar form but is still entire. This and the other specimens
show that the great length of the third lateral lobes and the apical bend in
the sutures and septa of adults are due to the retention of nepionic characters
and that the great complication in the details of the outlines and the large
number of lobes and saddles are based upon primitive nepionic outlines.
This is also apparent in the internal double curvature of the septa, which
are concave along the center and convex like those of most Ammonitinze
only at the dorsal and ventral lobes.
A fine young specimen, No. 18936, U.S. National Museum, Upper
Missouri, enables me to add the following: Whole diameter is 55 mm.,
and the fourth volution is about completed. On the early part of this
volution the sutures are the same as in the young specimen above
described. The characteristic deeply cut saddles and lobes of the western
form are already beginning to appear® and the first, second, and third
lateral lobes have about the same proportions as in the adult, but the fourth
lateral is only about half as long as the third lateral lobe. The sutures in
this specimen are not so distinctly separated as in the young one at same
age referred to, and are almost as closely intermingled as in the adult.
The usual band free of sutures occurs on each side of the venter. On
breaking down this specimen the sutures on the last quarter of the third
yolution were found to be more distinctly separated, the margins becoming
simpler, but the peculiar bands free of sutures on either side of the venter
are still present, and the species could hardly be mistaken even at this
«The external shell is preserved in the umbilicus, but there are no tubercles, and venter is
smooth on the cast of this part. The outer layer of shell of the last quarter of fourth volution is
preserved and shows same markings as above described at about same age in young specimen from
Nebraska.
230 PSEUDOCERATITES OF THE CRETACEOUS. ;
early stage on account of the much compressed wholly smooth volution
and narrow concave venter with slightly elevated acute ridges on either
side on the cast. At this age inner saddles assume a primitive rounded
form with expanded base and one marginal central lobe; the inner lobes
are trifid. Two specimens in the collection of the Boston Society of
Natural History, collected by Prof. W. G. Crosby, have the typical
characters and form of P. whitfieldi and are devoid of tubercles. The
sutures were not very clearly made out. The matrix has the aspect
of an arenaceous ? limestone, color light brown. The largest specimen
from Fort Collins, Colo., is 185 mm. and the smaller one from El Paso
County, Colo., 84 mm. in whole volution. One specimen in the collection
of the Boston Society of Natural History reaches 265 mm. in diameter and
has a concave ventral zone on both shell and cast at end of outer volution.
There are excessively faint tubercles along the umbilical shoulders but no
traces of them on the edges of the ventral zone, either on shell or cast.
The shell on this specimen and on several others is sufficiently perfect
to show that there are the following parts. An outer opaque probably
porcellaneous part of several layers, next a middle part with more or less
of luminous red coloration, also of several layers, and an inner part, also of
several layers, with the usual iridescence of nacreous shell
Two specimens from Loup Fork, Nebr., in the Museum of Comparative
Zoology, show the typical large siphonal saddle with dependent marginal
saddles of whitfieldi. One of them belongs to the parephebie stage of a
shell having at the same time concave venter on both cast and shell with
very faint tubercles, and the other and the two described next below
represent the gerontic stage of a shell of very large size of the same
species, with flattened venter on the cast and very faint concave zone on
the shell, but no signs of tubercles on this part. The umbilical shoulders
were destroyed. In both of these specimens from Kansas the ventral
branches of first lateral saddles did not reach the edges of the venter and
the same smooth band appeared on either side of this part as in other forms
of this group. I can not at present separate them from whitfeldi upon the
basis of their slight tuberculations, since faint tubercles are apt to be
present at some stage even in typical forms of this species. ee, :
F
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Figs. 1
Geese
Fic.
Fic.
2
uN
3. NSphenodiscus pleurisepta (Conrad)
PAL AS Evel:
SPHENODISCUS.
Nplenodiscus lobatts (Ta Om ey: eee are eee
Shows the abnormally shortened living chamber and flaring abnormal aperture and
partly absorbed sutures. Lander’s mill, Tippah County, Miss.; Ripley group;
Coll. U. S. Nat. Mus., No. 20577.
Sphencdiscus beecheripaly atti ee a ae eee ee ee eee
Birmingham, N. J.; Lower or Middle Greensand marls, Upper Cretaceous; Coll.
Yale Univ. Mus., No. 200.
. Sphenodiscus stanton? Evatt) 2. 22226 ce 4 ook er eee ore ee eee
Suture from specimen figured on PI. V, fig. 4, showing the principal saddles and
lobes, <3. ’
3uncombe Hills, Pontotoc County, Miss.; Ripley group, Upper Cretaceous; Coll.
Frederick Braun.
264
ut
lo}
U. 8. GEOLOGICAL SURVEY
MONOGRAPH XLIV
PL.
vi
SPHENODISCUS,
oie ©
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PLA evant
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Pa AW he Vole
SPHENODISCUS LOBATUS (Tuomey).
(Page 66.)
Fias. 1, 2. Pontotoc County, Miss.; Ripley group, Upper Cretaceous; Coll. U. S. Nat. Mus.,
No. 2403, } natural size.
266 .
AB3AYUNS 1v9IN01039 ‘Ss
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SPHENODISCUS.
Page.
Pies: 1, 2) Sphenodiscusilenticulais (Owen) eee. sese= = eee ee ae ae 71
Fig. 1. Young of supposed typical form, natural size. See also Pl. IX.
2. Suture of same 63.
Moreau Riyer,? Dakota; Fox Hills group; Coll. U. 8. Nat. Mus., No. 7754.
Fries. 3-7. Sphenodiscus lenticularis var. splendens Elyatt -- = 5.22522 22225 2-222 oe a = ee 75
Figs. 3, 4. Views of fragments showing lateral sutures and internal, loose younger
yolution, natural size.
5. Dorsal suture of one side of about same age as the one painted in on fig.
3, natural size.
6. Antistphonal lobe of fig. 5, much enlarged.
7. First three saddles and siphonal saddle to show outlines on the ‘next
inner yolution to that of fig. 3, natural size.
South Dakota; Fox Hills group; my collection.
268
PL. Vill
MONOGRAPH XLIV
U. S. GEOLOGICAL SURVEY
CUS,
Cc
>
PHENOD!
iS)
SS eee en a d : he ran CAs Meee
269
Ag exe
PA Wks, LOX
SPHENODISCUS.
Fras. 1-6. Sphenodiscus lenticularis (Owen) .-..-----------
Fig. 1. Suture of paranepionic substage, < 25.
2. Details of siphuncle, showing what seemed to be a collar above and a pro-
longed funnel reaching from the septum to the opening of the collar.
3. Sutures of the neanic stage, showing the division of the first primitive lat-
eral into three saddles, first, second, and third of the later stages, and
the mode of increase of the so-called auxiliary saddles and lobes on the
line of involution, X 4.
4. Section of the two youngest yolutions observed, >< + 4.
5. Lateral suture of later but not fully adult stage, x 6.
6. Dorsal suture of same age, * 8.
Rock Creek, Wyoming; Fox Hills group; Coll. Yale University, No. 1697.
Fics. 7-9. Sphenodiscus lenticularis var. mississippiensis Hyatt ........-..-.--+---------------<-
Fig. 7. Lateral suture, natural size.
8. Dorsal suture of same age, but one-fifth over the natural size; actual meas-
urement is 48 mm. instead of 60 mm., the length of the figure.
9. Lateral suture, natural size, from specimen in Coll. Acad. Nat. Sci. Phila-
delphia. :
Three miles northeast of Ripley, Miss.; Ripley group; Coll. U. 8. Nat. Mnsz.,
No. 20863e.
Wie. 10.) Sphenodiscus'beechert Ely ath e222 = fase aes wee See eee ae eee ee See eae ea eee
Suture, natural size. Fox Hills group; Coll. Mus. Comp. Zool., Cambridge.
Fras. 11-13. Sphenodiscus lobatus (Tuomey)
Fig. 11. Right side.
12. First three saddles of left side at same age, natural size.
13. First three saddles of left side of the youngest suture shown on Pl]. VII,
fig. 1, natural size, for comparison with fig. 12.
Buncombe Hills, Pontotoc County, Miss.; Ripley group; Coll. Frederick Braun,
Brooklyn, N. Y.
Page.
71
bos
b> f
66
oie ae
U. 8 GEOLOGICAL SURVEY MONOGRAPH XLIV PL. IX
SPHENODISCUS
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CormopocEerkAs, SPHENODISCUS.
Fires. 1=4") Covlopoceras novimexicamny liye rate metatarsal 94
Figs. 1-3. Natural size, showing hollow keel, etc.
+. One entire latewal suture and parts of two others, x 2. The terminations
of the saddles were more or less pointed depressions in the cast and
were not at first observed.
Near Carthage, N. Mex.; my collection.
Pies. (5=21., Cotlopoceras colleiiaicliyaititee = = ses ace ieayae rete ete 91
Figs. 5, 6. Natural size, section partly restored; see also Pl. XI, fig. 1.
7. Lateral suture same as in side view, X 2.
8. The dorsal suture of same age, but a suture or two later.
9. Youngest suture shown in fig. 5, x 2, showing the marked changes that
occur on this yolution.
10. First to third suture of nepionic stage, < 20.
lla. An entire suture of latter part of first volution, % 20.
11. Two entire sutures of first quarter of second yolution, 20.
12. Entire suture of fourth quarter of fourth yolution, x 8, when the sutures
are beginning to show subdivision.
13. The protoconch and part of the first volution, 22, same age as fig. 14.
14. More enlarged side view of the same. | D
15, 16. An older stage of the same shows less of the protoconch and more
sutures.
17, 18. A still older stage, showing the decreasing transverse diameter of the
yolutiean in the goniatitic stage, and the first constriction or mark of
a nepionic aperture.
19, 20. An older stage of same, center of fig. 6, and also of fig. 1, Pl. XI.
21. Shows the hyponomie sinus of constriction or permanent aperture given
in figs. 1S8and 19. The normal rate of growth and increase in diameters
of volution has begun in this nepionic substage.
Near Carthage, N. Mex.; my collection.
Fie. 22. [Suture of Sphenodiscus introduced for comparison.—T. W. 8.]
272
PL.
MONOGRAPH XLIV
U. S. GEOLOGICAL SURVEY
COILOPOCERAS, SHPENODISCUS
: ie
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PLA RE XT.
CormopocEerRAs, EULOPHOCERAS, METOICOCERAS.
Page.
Fic. 1. Cotilopoceras colleti Hyatt Pe ey ee ee ie ee RNS es ee ena SO 91
Section same as Pl. X, fig. 6, enlarged.
Fics. 2-6a. Eulophoceras natalense Hyatt ..-..-.--------------------------------------------- 86
Fig. 2. Side taken before specimen was ground to show section.
3. Section somewhat more than natural size, and somewhat restored, shows
the umbilicus on the right completely filled by the shell layers. This
filling oceurs in the adolescent stage, inclosing the dark spots on both
sides of the center, which indicate that the shell did not fill the umbilici
at an earlier stage.
4. Enlarged view of center restored.
5,6. Shows keel to have been solid at this age.
6a. Enlarged drawing of hollow keel of venter connected by a dotted line.
Natal, South Africa; Cretaceous; Yale Museum.
Bias. 7-24. Metoicoceras swallow (Slum and) eee aaa el ee 118
Fig. 7. Protoconch and part of nepionic yolution, 56+, actual transverse
diameter 3/10 mm.
8. Side view of same, showing the abrupt bend in the protoconch before the
nepionic tube began to be formed, and the first two sutures.
9. Optical section of same along dotted line in fig. 8 and from front of view
shown by the arrow.
10. Front view of the specimen before removal of the outer volution, x 36.
11. Enlarged view of the czecum and first section of siphuncle, showing also
the ventral lobe divided by a siphonal saddle.
12,18. Neanic stage, showing the aspidoceran-like form and tubercles, > 6.
14,15. A little older stage with living chamber complete at the umbilical
shoulder, over 1/2 volution in length, x 6. Back of this shows rounded
venter of the neanic stage just becoming divided by the incoming of two
rows of tubercles.
16,17. Early ephebic substage.
18. Sutures of fig. 12 about first quarter of fourth volution, < 12.
19. Suture of second quarter of same volution.
20. Suture of probably fourth quarter of same volution.
21. Dorsal suture of the second volution, x 12.
22. Dorsal suture of what was considered to be the last of fifth or part of sixth
volution, 12.
23. Dorsal suture later in age than fig. 22, x 12, of same age as suture Pl. XIII,
fig. 1.
24. Lateral suture of fig. 16 enlarged 3 diameters. The ventral lobe has been
distorted by setting the siphonal saddle at an eccentric angle.
Texas; Colorado epoch; my collection.
See P]. XIII for other figures of this species.
xl
PL.
MONOGRAPH XLIV
U. S. GEOLOGICAL SURVEY
EULOPHOCERAS, METOICOCERAS
COILOPOCERAS
:
:
Pi le 7
PAA, xerr:
CorLopocERAS, ACONECERAS, SPHENODISCUS.
Page.
ies) 1E3) (Corlopoceras'spniigent Ely att see - soe se eee ae eee oe ee eee 96
Fig. 1. Suture of right side of shell.
2. Suture of left side.
3. Antisiphonal lobe and first dorsal saddle. Lower part of lobe below dotted
line and right side is restored; the point, however, was seen to be bifid.
All natural size.
Rit du Plain, Colfax County, N. Mex.; Colorado epoch, Upper Cretaceous; Coll.
Mus. Comp. Zool.
fires) 4-6) Alconecerasinisum: (a2 Ox big) sete ere ee ae eee 100
Figs. 4, 5. Natural size (after d’?Orbigny’s figures) .
6. Sutures enlarged, showing similarity to phylloceran outlines.
Bia. 7. Coilopoceras grossouvrer Hyatt 100
Figure of supposed Sphenodiscus requienianus @Orb., showing coilopocerap suture.
(After Grossouvre. )
RUG, ShaSPlercocdtscus onic hats Meliy eth ere es ete ee 82
Fig. 8. Suture natural size. Part of one suture is shown and this is continued by
the auxiliaries of the next suture below.
Near Maestricht; Senonian; DeKoninck Coll. Mus. Comp. Zool., Cambridge.
276
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XII
COILOPOCERAS, ACONECERAS, SPHENODISCUS.
vauue
207
PEAVY Ee rhr:.
Merorcoceras.
Ries: 1-25 Metoicocenas swallovt (Shim ard) See ere
Fig. 1. Same as Pl. XI, figs. 20-23. First three saddles and two lobes of lateral
suture, X 12, to show mode of division of saddles and their distinct
marginals at this late neanic substage.
2. Grayson County, Tex; Coll. D. 8. Martin.
Bigs: 3-5: Meloworerasnchiter ely abuse — Sasol ree eee err
Fig. 3. Shows shell on part of outer volution and how little this differs from the
cast.
4. Shows this also as well as the rounding of the living chamber on the venter
in old age. See also younger suture from opposite or left side; Pl. XIV,
fig. 10.
5. Last suture of another specimen of about the same size as fig. 4.
Upper Kanab Valley, Utah; Coll. U.S. Nat. Mus.
PL. XII
XLIV
MONOGRAPH
U. S. GEOLOGICAL SURVEY
METOICOCERA
_
1
PAA DE Give
Merrorcoceras, VASCOCERAS.
Eras: 1=10! “Metoicocerasiwujviter ary atta ear eater aa et eee eee
Figs. 1,2. Exterior, natural size, showing living chamber nearly three-fourths of
a yolution in length, complete to its inner border.
3. Lateral suture of the last septum, X 3.
Elm Fork, Horton’s mill, Dallas County, Tex.; Colorado epoch.
4,5. Specimen somewhat older than fig. 1, natural size.
Probably from Texas; my collection.
6. Lateral suture, X 3. Living chamber, probably nearly complete, is
one-half of a volution in length.
7,8. Type of species, natural size.
9. Suture, natural size, somewhat older than fig. 4, whole diameter about 56
mm.
Elm Fork, Horton’s mill, Dallas County, Tex.
10. Lateral suture, left side of fig. 4, Pl. XIII, taken from halfway between
the base of the living chamber and the opening of the same.
Ries: 1114 Metotcocen cs accelerate Klay ait tere sey et tee ee
Figs. 11-18. Specimen in which the living chamber is complete and over tHree-
fourths of a volution in length, natural size.
14. Part of suture visible at base of living chamber on the opposite side to
that figured, 4.
Elm Fork, Horton’s mill, Dallas County, Tex.
Bic: 15. MetoicoceraswhitewElyatt) 3-e eee eee eee ee ee eee eee eee eee
Dorsal suture, natural size.
Elm Fork, Horton’s mill, Dallas County, Tex.
Fie. 16. \Vascocerasyhaniti (ly att) Fos sne seme eee eee eae eee eee eee
Suture, natural size.
280
127
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XIV
METOICOCERAS, VASCOCERAS,
‘
‘i a
.
PEA, Raye
281
PID AN ID 1B) OW
Merorcoceras, Hrrnzta.
Figs. 1—4.. Metoicoceras:swallovy | (Shumanrd))os<5- --=- sees eee eee ee eee eee 118
Figs. 1,2. The imperfect and crushed base of living chamber restored in fig. 2.
3,4. Right and left sutures of fig. 1, of same age, showing differences in
number and outlines of auxiliaries. All natural size.
Texas; Colorado epoch; Coll. Amer. Mus. Nat. Hist., New York.
ras. 5-8. Mfetoicoceras.qibbosum (elyatt. {222-2 ae oo a ee ee ee ee eee 121
Figs. 5, 6. Natural size.
7, 8. Suture of right and left sides, respectively, as seen when looking at the
specimen fig. 5, natural size.
Texas; Coll. Amer. Mus. Nat. Hist., New York.
Figs. 9-11. Metoicoceras kanabense Hyatt @.
Figs. 9, 10. Natural size.
11. Suture of left side of the second quarter of outer volution, x 23. The
living chamber extended from the crack in the specimen, fig. 10,
for the remaining one-half yolution, and was most probably nearly
complete.
Upper Kanab Valley, Utah; Colorado epoch; Coll. U. 8. Nat. Mus.
Figs: .12=18:-Heinzia matura ly abttss-3- =. enn = eee eee ee eee eee eee eee 132
Fig. 12. Entire specimen, right side.
13. Same separated and center excavated, left side.
14. Front view of same, center one-half restored.
15. Ventral view of fig. 12. F
16. Suture at place marked by arrow in fig. 18, 7, actual length 3 mm.
17. Dorsal suture, * 8, of second quarter of outer volution of fig. 12, one-half
actual diameter 2 mm.
18. Suture of right side fourth quarter of outer volution of fig. 12, x 3.
All natural size except figs. 16, 17, and 18. ‘
Escragnolles, France; Barrémian; Coll. Mus. Comp. Zool., Cambridge.
Hires. L920) emztanpo novi craryesn (A) PLOY) lester terete ee eae 131
Fig. 19. Dorsal suture next to outer volution across the umbilicus and opposite
termination of outer volution, * 9, one-half actual diameter 1.5 mm.
Of same type, but more immature at the same age than in Heinzia
matura.
20. Natural size.
Locality and collection same.
« No description of this species was found in the manuscript.—T. W.S.
282
U. S. GEOLOGICAL SURVEY
METOICOCERAS, HEINZIA.
MONOGRAPH XLIV
PL
- iene
eS eee
—
s
4
Ay
Lo
PRAT E XV ;
Hernz1a, KNEMICERAS.
Figs. 1-3. Heinzia provincialis (d’Orbigny) --2-------.----- === ===. <2 s= 2 2 en 131
Figs. 1,2. Same as Pl. XV, fig. 20, broken to show young, X 3.
3. Lateral suture of the second quarter of outer yolution of Pl. XV, fig.
20 os.
Escragnolles, France; Barrémian; Coll. Mus. Comp. Zool., Cambridge.
HiGs.4=8. Ainemicer.as synvGcume (vO EU) | ere tate ae eee 146
Fig. 4. Natural size, showing length of living chamber, over one-fourth of a
volution. Coll. Mus. Comp. Zool., Cambridge.
. Lateral suture, * 23.
6. Uncompressed typical fossil. Coll. Yale Mus.
7. Part of suture of right side, 23, to contrast with next figure.
8. Suture of left side, x 3. Outlines perfectly preserved.
or
Mount Lebanon, Syria; Cenomanian.
Figs. 9-10. Knemiceras compressum Hyatt. Natural size _..-...-.--.------------------------- 149
Locality, same as last; Coll. Mus. Comp. Zool., Cambridge.
Fias. 11-14. Knemiceras compressum var. subcompressum Hyatt. ..--.-------------------------- 150
Fig. 11. Specimen in collection of Columbia University.
12. Section showing transition from a rounded young to the flat and then con-
cave venters of the succeeding stages, 2, from specimen in Mus. Comp.
Zool., Cambridge.
13a. Enlarged view of center.
13b. Enlarged view of protoconch and first volution with first and second
sutures. °
14. One of Conrad’s specimens, natural size. Suture abraded. Coll. Yale
Mus. :
Locality, same as last.
Bias: 15-18) ‘Kmemiceras compressunn uy a ube eee oe sees eee eee ee 149
Figs. 15,16. Type of species. Sutures abraded. :
17. Suture from line of involution to first lateral lobe at breadth of 54 mm. on
left side.
18. Suture on right side to third lateral saddle at breadth of 63 mm.
Locality, same as last.
Fic. 19. Knemiceras compressum var. subcompressum Hyatt...----.---------------------------- 150
Ventral view, natural size, of specimen in collection of Columbia University. For
sutures see fig. 11.
Locality, same as last.
284
SS nd
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XVI
‘a ide
err 6 Fee
- Ta a
sd
HEINZIA, KNEMICERAS
= om Ou
as
'
i
{
a >
“a a a]
SPATE Seyaii
285
PAV Viale
SUBPULCHELLIA, NICKLESIA, PULCHELLIA, KNEMICERAS, PROTENGONOCERAS.
PIGs. lab) Sud pulcnelliarcastellanenist sally aut tre riers ae ete = ake ate eee 140
Figs. 1, 2. With shell complete on side of fig. 1.
3, 4. Same fossil, shell partly taken off. Right side of fig. 3 shows length of
living chamber about one-half of last volution.
5. Lateral suture of fig. 5, < 3.
All natural size except fig. 5.
Castellanes, France; Neocomian; Coll. Mus. Comp. Zool., Cambridge.
Rigs. 6-8: Vicklesia. dumasianal (a? Onbigny) ees. o22e ee aaeee eee eee sees eee eee eee 139
Figs. 6,7. Natural size. ,
8. Lateral suture, < 3.
Locality and collection same as last.
Eres: 9=12) Pulchelliacompressissima (G2 Onbignly,) Sas. J22 = se = == eee ee eee eee 142
Figs. 9-11. Natural size.
12. Suture after Nicklés, Pal. sud-est de l’ Espagne, pl. 3, fig. 1b, x 4.
: Locality and collection the same.
Bics 13—15,, Knemiceras attenuaium) (bby ath) aes sees] see ee ee eee eae eee ase eee eee 151
Figs. 13, 14. Natural size; shows living chamber nearly three-fourths of a volution.
15. Suture, < 2.
Celendin, Peru; Cenomanian ?
Frias: 16=20% Protengonocerasgab0ts (sO Lm) meee see ee ee cee 153
Fig. 16. Shows living chamber to have one-half a yolution in length. Shell is
preserved on the living chamber.
17. Section shows the concave venter with lateral ridges at an early stage.
18. Ventral view of same.
19. Septum of same, 2.
All natural size except the last, and all in Coll. Mus. Comp. Zool.,
Cambridge.
20. Specimen in Coll. Acad. Nat. Sci. Phila. Showing living chamber one-half
of a volution, part of aperture on right side, and old-age folds.
Arivechi, Sonora, Mexico.
286
U. S. GEOLOGICAL SURVEY
MONOGRAPH XLIV PL. XVII
SUBPULCHELLIA, NICKLESIA, PULCHELLIA, KNEMICERAS PROTENGONOCERAS
oy 7 a ee an - = -
a ee. Ln? & = a
oa
: oS
4 : S|
H
pee, A. ; |
- PLAT te Saverio
Kwemiceras, ENGONOCERAS, PROTENGONOCERAS.
Page
BGS! L325 ne micerct sg DUN y aU te 152
Figs. 1, 2. Natural size. (After Gabb. )
3. Lateral suture enlarged. (After Gabb. )
Quebrada de Huari, Peru; Cenomanian?
Bias. 4,5. ingonocenasioeuidenense (Cragin) ssmee eee = nee ease ae ee 158
Figs. 4, 5. Lateral and ventral views.
Belvidere, Kans.; Washita epoch; Coll. Cragin, Colorado College.
156
Eres: 6-9! Protengonoceras planum) Hyatt] === assesses = eee eee ee ee
Figs. 6, 7. Lateral and ventral views, x 2.
8. Lateral suture, 2; the auxiliary saddles Nos. 8 to 10 should be a trifle
broader.
9. Dorsal suture of the same age, X 2.
Texas, my collection.
285
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XvViil
KNEMICERAS, ENGONOCERAS, PROTENGONOCERAS
PLAC xoixe
ENGONOCERAS.
Page
Bias, 1-6! Brgonocerasuddent, (Cree irl) eres errata ee 159
Figs. 1,2. Type specimen from near Lindsborg, Kans., natural size.
3. Lateral suture of same, slightly enlarged.
4,5. Specimen from McPherson County, Kans. Natural size, showing living
chamber probably almost complete along the umbilical shoulder and
about one-half of a volution in length. The crease on the side of the
venter of fig. 5 is an accident due to compression. Coll. U. 8. Nat.
Mus.
6. Lateral suture of opposite or left side, x 23. The curvature is somewhat
less than it is on the specimen.
Kiowa shales, Comanche series, Lower Cretaceous; my collection.
Figs.. 7=14) Pngonocerasiserpentinum) (Gragin)) = eeese]4 = see eee eee eee eee a 162
Figs. 7,8. Natural size, living chamber one-half of a volution probably nearly com-
plete on umbilical shoulder. The venter of inner volution of fig. 8 is
decidedly concave.
9. Lateral suture, * 2.
10. Part of sutures of young fragment, < 2. This specimen is from near Deni-
son, Tex.
11. Variety with broad ends to the costee and crowded peculiar sutures.
12. Lateral sutures, * 2.
13. Ventral view of cast, with similar coste. "
14. Suture of same more like those of fig. 9. This is not due to difference of
age. The last 5 and half of sixth saddle are dorsal.
Four and one-half miles northeast of Gainesville, Tex., Denison; Washita epoch;
Joll. U. 8. Geol. Survey.
Fics. 15=1/7. JEngonocerasiretardum: atten eee eee ee eee ee eee eee eee eee ee eee)
Fig. 15. Natural size, showing the late age at which the venter remains angulated,
flat, and without tubercles. The rounded yventer of the older stage is in
part due to abrasion.
16. Shows what was seen of the lateral sutures.
17. Dorsal suture of same age as oldest suture on fig. 16.
Near Pottsboro, Tex.; Upper Comanche (Grayson), Washita epoch; Coll. U.S.
Geol. Survey.
«The specimen here figured as HE. retardum is described as 2. uddeni on page 160.—T. W. 8
290
U. 8S. GEOLOGICAL SURVEY
MONOGRAPH XLIV PL, XIX
ENGONOCERAS
7
9
@
'
f ae
‘ i
i ; i
i) j - *\ te
i!
if) .
i
Al
i
| 2 oy nf
Hi ;
' r
in ‘i
1 : te ow | i
i
6 ss - Fee
}
- i
-
at a4
i
P ya } BS
: ; :
7 a
. =
= 1
4 * tg =
a .
. 2
, ; ‘
5
— aa i -
- - ‘ q 7
! 7” ‘
on Lae ¥
A
j \ n _
va ed al ee
“~~ al ra
sy - Y 1
_ 1a
b | ‘
2 ae
= -
e: i
> 2 ss a
7 -_ Fe a. ae
C , “3 ’
pied 9
= ;
; re - rn
7 i
‘
+
- U ‘Tg Lys \
A 3 . f
a ne
=
, se I
x ®
r
ri
‘
‘ 7 ae
“yy
D $
Sheet alls
A i
*
_ of
a iJ r %
2 ¥ 7
AY “
i "i
nies A
at Ve ~
“a eee
« t hg
t -
;
A i
; ne —
t
«
~
‘
- -
—
JE byes So
PicdA Thee xX:
ENGONOCERAS.
Page.
Hires: 1-5: “Engonoceras)serpentinum (Cragin))¢ 2-522 - ss2ce sm see = eee eee eee ees 162
Fig. 1. Suture showing all of one side, part of the other and dorsal suture, x 2. +
2,3, 4. Three views of one of Cragin’s figured types.
5. Suture of same, x 2.
Near Denison; Washita epoch; Coll. Cragin, Colorado College.
165
Bigs. 6-13 Pngonoceras pier denale, (von boCD) a oss- eee eae nee eee eee eee eee eee
Figs. 6, 7. Specimen from Towash, Tex.; Coll. Mus. Comp. Zool., Cambridge.
8. Suture of same, 2.
9, 10. Specimen from near Cerrogordo, Ark.; Coll. U. S. Nat. Mus., No.
22648. :
11. Suture of same, natural size.
12. Specimen from Seyen Knobs, 5 miles southeast of Glenrose, Tex.
13. Suture of same, X 2.
Fredericksburg group, Comanche series.
PL. Xx
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV
ENGONOCERAS.
4 aN
(iy 2
4
>
=
oF
¢
i .
7
i
PEAT Xo: | #
!
293
PLATE XXL
ENGONOCERAS.
Page.
Fic. 1. Engonoceras pierdenale var. commune Hyatt...-.--------- babies Hace Soeaee eee eee 165
Fig. 1. Suture, * 2. Bell County, Tex.; Fredericksburg group, Comanche series.
Coll. U. 8. Nat. Mus., No. 8301.
168
BYGS5i2=65 EGON OCEr as SUD) ECE say NU Gre ee ee
Figs. 2,3. A specimen from Gabriel, Williamson County, Tex:; Coll. Mus. Comp.
Zool., Cambridge.
4. Portion of septum of same specimen—the middle one of the three indis-
tinetly shown in fig. 2, X 2.
5. Last septum of same specimen, 2.
6. Septum of a smaller specimen from same locality, 2. .
Washita(?) group, Comanche series.
294
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XxI
ENGONOCERAS
oe * fs
t
q
;
ra
v] <
‘ : :
4
x.
'
' > mms
;
4
< 7
: a
/ ;
a
;
~
ee ier ee aero ov
a a
e
Fa
f a
SEN AMPE xi
PLATE Sexe
ENGONOCERAS.
Ries. 1-5. “Engonoceras subject Ty atti. 5 5-1-5 ee ole ee ee eee eee
Fig. 1. Specimen from Dueck Creek beds, near Denison, Tex.; Coll. U. S. Geol. Surv.
i)
or Hw CO
. Suture of same, very slightly abraded, x 2.
. Specimen from Grayson, Tex.; Coll. D. 8. Martin.
. Suture of same, * 2.
. Suture of specimen from Tarrant County, Tex.; Coll. Cragin, Colorado
College.
Washita (?) group, Comanche series.
ies. ‘6-10: ‘Engonoceras) qibboswm Ehyatt 22-22 == = eae ee ase eee eee eee ee eee eee
Fig.
6.
Je)
10.
wn ~1
Lateral view of a small specimen from Goodland limestone, 15 miles west
of Denison; Coll. U. 8. Geol. Sury.
Ventral view of same, partly restored.
Septum of same, X 2.
Fragment doubtfully referred to the species, from Bell County, Tex.: Coll.
U.S. Nat. Mus., No. 8301a, x 2.
Septum of same, partly restored, < 2.
Fredericksburg group, Comanche series.
296
171
U. S. GEOLOGICAL SURVEY
MONOGRAPH XLIV PL. XXII
ENGONOCERAS.
"it
<2
aA a
erie Ann exe:
NY AAR I OX CIVIL,
EENNGONOCERAS.
Hrasivl=65 Pngonoceras gibbosum Elyattes seer osc eee ee eee enon eee nae ae eee eee 171
Figs. 1, 2. Specimen from Cook County, Tex.; my collection.
3. Suture of same, x 2.
4, 5. A fragment from the Goodland limestone, 15 miles southwest of Gaines-
ville, Tex.
6. Suture of same, X 2.
Fredericksburg group, Comanche series.
Fias. 7-9. Engonoceras stolleyi Bbhm...--..-------- obs scuide- cteeeseeesweekes oe sceaee eee 175
Figs. 7, 8. Young specimen in Cragin Collection, Colorado College. '
9. Suture of same, X 2.
Fredericksburg group [?], Comanche series.
bo
We}
Loe)
U. 8. GEOLOGICAL SURVEY
ENGONOCERAS,
MONOGRAPH XLIV
PL. XXII
1
- ‘a
d
“a
’
m4
P:
AS
=
-
we
t
U _ —
_ . . 7
An xa
299
PLAT EH XC
ENGONOCERAS.
EYGSs 15a EGON OCeras) SEM t ESO EINE ot tae cece
Figs. 1, 2. Specimen in my collection, partly restored. ;
' 3, 4. Specimen in Coll. Hill, U. 8. Geol. Surv. [‘‘ Hill 4a.’’] (?)
5. Suture of same, X 2. This is somewhat worn down.
Fredericksburg group [?], Comanche series. ;
Figs. 6—8. Hngonoceras complicatum Ebyatt -<---- =~ =~ onsen ana ee ee a ee
Figs. 6, 7. Type specimen from near Austin, Tex. Coll. Hill, U. S. Geol. Surv.
8. Suture of same, X 2.
Comanche Peak limestone of Fredericksburg group, Comanche series.
300
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXIV
ENGONOCERAS.
eee XOX
PLATH-X kV:
NEoLositEs, METENGONOCERAS.
Page.
Bigs. 1—4. Weolobiesichoffaty Hyatt. 2-2. cea. 2 ee ee Ue eco oesbersaseososocsces 178
Fics. 1, 2. Copies of Choffat’s figures 3a, 3b, published as NV. vibrayeanus.
3, 4. Suture of probably the same species (after Choffat). '
Cenomanian; Portugal.
RIGS. 5-9. Metengonocerasimecriptumiblyathese. === eee nee ee ae eee eee eee 180
Fie. 5. Section of fragmentary specimen from west of Walnut Springs, Texas:
Coll. Cragin, Colorado College.
6. Suture of same, enlarged.
7. Suture of asmall fragmentary specimen from 12 miles northwest of Decatur,
Tex.; Coll. U. S. Geol. Surv. ;
8. Suture of fragment from 15 miles west of Denison, Tex.; Coll. U. 8. Geol.
Surv.
9. Ventral view, partly restored, of specimen from 12 miles northeast of
Decatur, Tex. For other figures see.P]. XX VI.
Fredericksburg group, Comanche series.
302
MONOGRAPH XLIV) PL. XXV
U. S, GEOLOGICAL SURVEY
NEOLOBITES, METENGONOCERAS.
lediwaitis,
303
PLAT E-XX VL.
METENGONOCERAS.
Bias: I-44. Metengonocenasanscriptece Acyl treats ae oleae la are er
Fig. 1. Enlarged suture of specimen represented by figs. 2 and 3, and by Pl. XXV,
fig. 9.
2, 3. Specimen from 12 miles northeast of Decatur, Tex.
4. Suture of large fragment from 9 miles from Austin, on Beecaves road.
Coll. U.S. Geol. Surv. [This drawing was labeled M. ambiguum, but the
specimen is described under M. inscriptum.—T. W. S.]
Fredericksburg group, Comanche series.
Fies. 5-7. Metengonoceras ambiguum Hyatt.....---------------<---------------------------=-
Fig. 5. Side view of type.
6, 7. Suture of same specimen, X 2.
Nine miles from Austin, on Beecaves road; Fredericksburg group, Comanche
Peak limestone, Comanche series. Coll. U. 8. Geol. Sury.
Big: 8. MMetenganocenas ra Cuter y Abts ia meee ral a er ase
Side view of fragmentary type specimen.
Elm Fork, Dallas County, Tex.; probably Eagle Ford shales, Upper Cretaceous.
Coll. Mus. Comp. Zool., Cambridge.
183
184
U, 8. GEOLOGICAL SURVEY
MONOGRAPH XLIV) PL. XXxVI
METENGONOCERAS
PLATE XXVIL
METENGONOCERAS, PLACENTICERAS.
Hies., 1-2: Metengonoceras acutumibly atte=- ose eee ees ee eee eee 184
Fig. 1. Ventral view of type specimen.
2. Septum of same, 2.
Elm Fork, Dallas County, Tex., probably Kagle Ford shales, Upper Cretaceous.
Coll. Mus. Comp. Zool., Cambridge.
IGS. 3-14 Meten gon ocen cs seul (Cre 00) eet eee ree 185
Figs. 38,4. Lateral and ventral views of specimen described.
5. Section of same.
6. Inner whorls of fig. 5, enlarged.
. Center of same, still more enlarged, showing antisiphonal lobe, the inner-
“I
most whorls having dropped out.
8. Section of whorl in neanic stage, < 10.
§. Adult lateral suture, * 23.
10. Last lateral suture, < 23.
11. Dorsal suture continuous with fig. 9, enlarged.
12. Dorsal suture one-fourth yolution older than fig. 11, enlarged.
13. Lateral and part of dorsal suture of neanic stage, >< 18. '
14. Dorsal suture of somewhat later substage than fig. 13, enlarged.
Four miles east of Whitesboro, Tex.; Eagle Ford shales, Upper Cretaceous; Coll.
U. 8. Geol. Surv.
Bids: 15-17, Piacenticenasrsyntale (Morton) eemee see -e ae eee eee eee eee ee eee eee 205
Fig. 15. Suture of the type in Coll. Acad. Nat. Sci. Phila.
16. Lateral suture of var. halei, Coll. Bost. Soc. Nat. Hist., No. 857
17. Dorsal suture of older part of same volution as fig. 16.
Greene County, Ala.; Eutaw beds (?), Upper Cretaceous.
“I
306
PL. XXVIII
MONOGRAPH XLIV
U. S. GEOLOGICAL SURVEY
Sst
.eeaT
+: >
METENGONOCERAS, PLACENTICERAS
®
.
Ar
307
ow
}. Another specimen of var. ha/ei, same collection.
PL AU Ee xex Vee
PLACENTICERAS SYRTALE (Morton).
(Page 205. )
Two views of the type, Coll. Acad. Nat. Sci. Phila. (For suture, see Pl. XX VII,
fig. 15.)
Type of var. halei, Bost. Soc. Nat. Hist., No. 8577. (For suture, see Pl. XX VII,
figs. 16 and 17.)
Kutaw beds(?), Upper Cretaceous, Greene County, Ala.
308
PL. XxvII
MONOGRAPH XLIV
U. 8. GEOLOGICAL SURVEY
PLACENTICERAS.
7)
ba
7
oy
hs:
i
id
.
LATE Xb.
ie
309
PLAT HE) Xa
PLACENTICERAS GUADALUP® (Roemer).
(Page 197. )
Fig. 1. Lateral view of a large specimen.
2. Aperture view of same considerably restored.
3. Section of same.
4. Enlarged section of inner whorls of same.
Near Fort Worth, Tex.; Taylor beds (?); Upper Cretaceous; my collection.
310
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV) PL. XXIx
PLACENTICERAS.
PSLcAs Ry XXX
PLACENTICERAS SANCARLOSENSE Hyatt.
(Page 200. )
Fig. 1. Side view of an average-sized specimen
2. Aperture view of same.
3. Suture of same, * 2.
San Carlos, Presidio County, Tex.; San Carlos beds ; Upper Cretaceous; Coll. U. S. Geol. Surv
312
’
XXX
PL.
MONOGRAPH XLIV
U. 8, GEOLOGICAL SURVEY
PLACENTICERAS
7
-
1aggs 4
io
i ; “Se
te
‘< oe
4
PLATE. XXXL
PLACENTICERAS.
Page.
Hires. 1, 2) Placenticeras sancarlosense: elvy aiuu ps 2 sete eee et 200
Fic. 1. Section of a small specimen—‘‘passage form between this species and
guadalupze.”’
2. Side view of same.
San Carlos, Presidio County, Tex.; San Carlos beds, Upper Cretaceous; Coll.U. 8.
Geol. Sury.
IGS. jo—D= PUA CENEICEr OS) MEU ETI NL y AUG By ate ste ae 203
Fig. 3. Side view of the type specimen.
4. Section of same.
5. Aperture view of same. A
Near Presidio Del Norte, Chihuahua, Mexico; San Carlos beds, Upper Cretaceous;
Coll. Columbia University, No. 100738G.
314
b. 8. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXXI
PLACENTICERAS
i ii
Li
if
wh
«or
Te
Pola Ee Xe Xe ee
__. PLACENTICERAS SANCARLOSENSE var. PSEUDOSYRTALE Hyatt.
en (Page 200.)
Side view of type of variety (see Pl. XX XIII, fig. 1).
Near Fort Worth, Tex.; Taylor beds (?), Upper Cretaceous; my collection.
316
tage A
oe
ae
MONOGRAPH XLIV PL. XXXII
U. 8, GEOLOGICAL SURVEY
PLACENTICERAS
- ——
lon
7 j
'
,
a }
J
ae <<
‘ *
7
. i’
'
m
, : .
i
*
' e.
:
a
\
r =
Pe eLATh xoxo qe
» »
317
aes a
PapAD Ey XX err
PLACENTICERAS.
Page.
Rie. Ws Placenticerasisancarlosense vars pseudosyntqle Ly athe eee eens eee ee 200
Fig. 1. Aperture yiew of specimen figured on Pl. XXXII.
202
Pies. 2-4. sPlacenticenas planunm bly ait, = sess eee see ener hee nae ee ee
Fig. 2. Aperture view of medium-sized specimen partly restored.
3. Side view of same.
4. Peripheral view of another specimen showing less development of nodes.
(See Pl. XOXXIV, fig: 1.)
San Carlos, .Presidio County, Tex.; San Carlos beds, Upper Cretaceous; Coll.
U. 8. Geol. Survey.
318
U. §. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXXII
PLACENTICERAS
SP aeg,
“*
PLATE - XXXIV
PLACENTICERAS PLANUM Hyatt.
(Page 202.)
Fic. 1. Side view of the small specimen represented by Pl. XX XIII, fig. 4.
2, 3. Aperture and side views of a larger specimen.
San Carlos, Presidio County, Tex.; San Carlos beds, Upper Cretaceous; Coll. U. 8. Geol. Survey.
320 .
U. 8. GEOLOGICAL SURVEY MONOGRAPH XLIV) PL. XXXIV
2 vA XeROavie
PLACENTICERAS INTERCALARE Meek.
(Page 207. )
Fies. 1, 2. Side and aperture views of medium specimen (see Pl. XXXVI, fig. 1).
[Black Hills?], Fort Pierre, Upper Cretaceous; Coll. Yale University No. 1863.
299
ole
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXXV
PLACENTICERAS
¢
| ¥
a
PLAT Some val aye ‘i
TRC MPD, NOOK WL:
PLACENTICERAS INTERCALARE Meek.
(Page 207.)
1. Opposite side of specimen figured on Pl, XXXY.
2, 3. Side and aperture views of small specimen, No. 2104b.
4. Suture of same, 2.
5. Parts of two septa of Geological Survey specimen from Harper, Wyo., represented by
Pl. XXXVI, figs. 1, 2:
Fort Pierre, Upper Cretaceous, Coll. Yale University (except fig. 5).
324
U. 8. GEOLOGICAL SURVEY
MONOGRAPH XLIV PL. XXXVI
PLACENTICERAS
-
-
.
-
.
+
- a
:
=
‘
-
s
‘ SS
> ve
-
.
PLATE XXXVIL
4 225
PAB, XN Veale
PLACENTICERAS INTERCALARE Meek.
(Page 207.)
Fics. 1, 2. Fragmentary small specimen from near Harper, Laramie Plains, Wyo.; Coll. U. 8. Geol.
Survey. (See Pl. XXXVI, fig. 5.)
€ “ce
3. Section of specimen ‘‘approximating to some varieties of P. stantoni,’’ from Ponil Canyon,
New Mex.; Coll. U. S. Nat. Mus., No. 9735.
4. Side view of same specimen. (For suture, see Pl. XX XVIII, fig. 1.)
Montana group, Upper Cretaceous.
326
XVII
MONOGRAPH
U. §. GEOLOGICAL SURVEY
a * {
Mew! , i , is
"sy wee
eleva OCU
327
oo
Po, AGE Ee Xx ee ighe
PLACENTICERAS.
Fig.l. -Placenticerasintercalare Meek. 22 en eaten = see ee eee eee eee eee ee
Suture of specimen from near Harper, Wyo. (See Pl. XX XVII.)
Montana group, Upper Cretaceous.
Fig. 2: Placenticeras intercalare var. costatwm Hyatt -..--.----.-----------------
Side view of type of variety, my collection, purchased from Ward.
Black Hills, 8. Dak.
Montana group, Upper Cretaceous.
328
Probably from
XXXVUIL
PL.
xLIV
MONOGRAPH
§. GEOLOGICAL SURVEY
u
PLACENTICERAS
awe,
= 4 ft
PLAT Hs SOqiGie cael |e ae
PAD ie ee:
PLACENTICERAS.
Page
breswils/2. Placenticeraswntencalane: vans costal lly autor: sane eee ee ae ee ee 207
Figs. 1, 2. Aperture yiew and suture of specimen represented by Pl. XX XVIII,
fig. 2:
Fics. 3-6. Placenticeras placenta (Dekay ) Sane eee Ee oe eee ee Se Bee ee ee ee 211
Fig. 3. Fragment of a small specimen from Chesapeake and Delaware Canal,
Coll. Acad. Nat. Sci. Phila.
+. Suture of same, * 2.
5. Side view of small specimen from Lenola, N. J.
6. Sutures from smaller end of volution represented by fig. 5 enlarged four
diameters (see Pl. XL, figs. 1, 2).
Matawan (?) formation, Upper Cretaceous...
PL. XXXIX
MONOGRAPH XLIV
U. §. GEOLOGICAL SURVEY
ERAS,
Cc
PLACENTI
AE Xa:
1 eal bys Gl hel Sse i
PLACENTICERAS.
Page.
ES Se eae Roce ciate oem ec SS pedo] sSoaAce Seoul 211
Fig. 1. Peripheral view of specimen represented by Pl. XX XIX, fig. 5.
2. Side view ot same, enlarged nearly two diameters.
Wigs Sle PELACENUCEN CS ISLCNeLOTED Malay DOLL Dey Ut types ea 214
Fias. 1, 2. Placenticeras placenta (Dekay )
Figs. 3,4. Aperture and side views of the small specimen from Tarrant County,
Tex., in the Martin collection, Rutgers Female Institute, described by
Meek as P. intercalare.
5. Suture of same, * 2.
6. Fragmentary specimen from Horton’s mill, Dallas County, Tex.; Coll. Mus.
Comp. Zool., Cambridge.
7. Lateral and internal suture of same, * 2. (See Pl. XLI.)
Taylor beds (?), Upper Cretaceous.
332
XL
PL.
MONOGRAPH XLIV
U. 8. GEOLOGICAL SURVEY
Vee a
- $s isen a a «
rae =. .
, eh
i ah
* aes a
y,
*
es 4
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é 7
(Page 214.) cP a
Fia. 1. Sectional view of specimen represented by Pl. XL, figs. 6 and 7. ; = :
2. Restored section of same. abs ; ; »
3,4. Living chamber of a larger specimen. ) ;
5. Last suture of same specimen. ' “a
6,7. Living chamber of another specimen. ;
Horton’s mill, Dallas County, Tex.; Taylor beds (2), page Cretaceous; Coll. ve. ae Zool,
Cambridge. Ae rates
334 i : i pe
ae
Se
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XL
PL.
MONOGRAPH XLIV
U. S. GEOLOGICAL SURVEY
ENTICERAS.
PLAC
PAA tele le
PLACENTICERAS STANTONI var. BOLLI Hyatt.
(Page 214.)
Fic. 1. Suture of young specimen enlarged about 2} diameters.
2. Part of living chamber and last’ septa of a large specimen.
Horton’s mill, Dallas County, Tex.; Taylor beds (?), Upper Cretaceous; Coll. Mus. Comp. Zool.,
Cambridge.
336
PL. XLII
MONOGRAPH XLIV
SURVEY
GEOLOGICAL
&.
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CERAS.
SENTI
PLA
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PLACENTICERAS.
Bias: 1) 2: Placenticeras stanton’ vars bolly Ey atttes a= -- ease a eee ee eee
Fig. 1. Side view of small costate specimen.
2. Suture of same, 2.
Horton’s mill, Dallas County, Tex.; Taylor beds (?), Upper Cretaceous; Coll.
Mus. Comp. Zool., Cambridge.
Ries: 2—1dk sPlacenticerasipseudoplacenta Wyatts- - 22. - == s eres =e ese eee eee
Fig. 3. Side view of small fragmentary specimen.
4. Sectional view of same.
5. Center of same enlarged.
6. Ventral view of first whorls of same specimen much enlarged.
8. Inner whorls of another specimen, natural size.
—~I
,
9, 10. Lateral sutures of last whorl of same as indicated on fig. 7. U
Upper Kanab Valley, Utah; Colorado group; Upper Cretaceous; Coll. U. 8. Nat.
Mus:, No. 22344.
11. Parts of internal sutures of ephebic stage when dorsoventral diameter of
volution measures 49 mm.
Muddy Créek, Huerfano County, Colo.; Fort Benton formation; Upper Cre-
taceous; Coll. U. S. Nat. Mus., No. 22199.
U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XLIII
PLACENTICERAS
PA 2 Saat
PLACENTICERAS PSEUDOPLACENTA Hyatt.
(Page 216.)
Fics. 1, 2, 3. Three views of living chamber of fragmentary specimen.
Bad Lands, near Black Hills; Upper Cretaceous, 8. Dak.; my collection.
340
U. 5. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XLIV
PLACENTICERAS,
—"
PAGER ocean
34]
PALATE xe av
PLACENTICERAS.
Page.
Fies. 1, 2. Placenticeras pseudoplacenta var. occidentale Wyatt - - - - - Ee eee ee eee eee et eG
Fig. 1. A specimen from the Upper Missouri Riyer; Coll. Columbia University,
No. 10622G. :
2. Suture of a young specimen from Horton’s mill, Dallas County, Tex.;
Coll. Mus. Comp. Zool., Cambridge.
Fies. 3-16. Placenticeras whitfieldt Wyatt -- 22. ---22--=------ = = a 221
Fig 3. Side view of small fragmentary specimen from Clifford, Nebr., in Coll.
Mus. Comp. Zool., Cambridge, enlarged.
4. Section of same showing yenter of earliest whorls, 3.
5. Center of same, & about 63 diameters.
6. First two sutures and beginning of siphuncle of same specimen, much
enlarged.
7. Beginning of siphuncle of same after etching with acid, still further
enlarged.
8-10. Early stages obtained by breaking down a larger specimen from the
Black Hills, South Dakota, in my collection; enlarged about 5 diameters.
11-14. Complete sutures from dorsum to venter of same stages as figs. 8, 9, 10.
Fig. 11 is earliest suture visible on fig 9; fig. 12 is on last quarter of
same whorl; fig. 13 is last suture on fig. 10, and fig. 14 is nearly a yolution
earlier.
15. Dorsal (internal) sutures at diameter of 15 mm.
16. Same at diameter of 40 mm. The last two figures may not be from same
specimen as figs. 8-l4.
Montana group, Upper Cretaceous.
O49
ote
PL. XLV
MONOGRAPH XLIV
U. 8, GEOLOGICAL SURVEY
PLACENTICERAS.
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(Page 221.) — ae :
Fics. 1, 2. Two views of a large specimen, ;'; actual diameter. ave.
Black Hilis, South Dakota; Montana formation, Upper Cretaceous; Coll. Bost. Soe. Nat Hist.,
No. 11124.
544
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Bias. 14.) Placenticerasuhijeldn Wy atte sess oe se ee een ee eree eee eee Renee eee eee eee 221
Figs. 1, 2. Two views of the inner whorls of a small specimen from the Usper
Missouri; Coll. U. S. Nat. Mus., No. 18936.
53. Fragment showing peculiar sculpture of the inner shell layers, probably
from Black Hills, South Dakota; my collection.
4. Another specimen showing similar sculpture from same collection and
region.
Montana group, Upper Cretaceous.
Fic. &: ~‘Blaceniceras wititfielan var. tuberculaiumebivyatiees == see eee oe ae e eae eee eee 232
Fig. 5. Side view of the type of the variety.
Montana group, Upper Cretaceous; Black Hills, South Dakota; my collection.
Bigs: 6-8. - Placenticerasispillmant Hyatt 22 ates ee ae Ee eee 233
Figs. 6, 7. Two views of the fragment on which the species is based.
8. Part of weathered suture of same.
Ripley formation (?), Upper Cretaceous; Mississippi (?); Coll. Acad. Nat. Sci.
Phila.
[ Norr.—Professor Hyatt indicated that the drawings for figs. 6 and 7 were unsatisfactory
to him, but the specimen is too imperfect to serve as the basis for a restoration].
346
MONOGRAPH XLIV PL. XLVII
U. S. GEOLOGICAL SURVEY
PLACENTICERAS
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INDEX.
(Names in italie are synonyms;
in italic denote illustrations. ]
Page.
PA CATON OCCLAS ore lettin nialeleieletainiciewiw'cfele ms ciaieiale isle watcte ssn no 27
Bp NIPENU WLR CS nce omic seis ene ace celica see 110
Acceleration of development. ................- 19-23, 189-190
Acompsoceras Hyatt .............-..-...55 105, note; 111-112
bochumense:(Schititer) ---.--.-..---2- 0. sae 111-112
ESSENO ENE INCDINTCR) = cee c i. on eslncesl- == aaa ne 112
MEME VACTHIN GOLUDE) stem eins cee ainseisicien si slasica sem 112
PACONIECETASI ELV AUG oo. einen fot tice asec setnes £8, 100, 101, note
miguing (G.OrDIEN Vy) sean aaaccle seco <6 Je $0, 99, 100, 276
PAP RSSIC CLAS eens sista aes wefan Sain ocian Raise nies coos 24
Rls eur ge eet ee tote et td Sot torneo eas oleh an 24
Amaltheus ebrayi de Loriol. 234
Ammonites ...........---..- 43
attenuatus Gabb - aa aby
balduri Keyserling-. - 191,192, 244
belviderensis Cragin ~ ¢ 158
bidorsatus Roemer -- - 243, 244
bilobatus Gabb- . 30
caicedi Karsten ... 133
catillus d’Orbigny... 143
elypeiformis @ Orbigny . $5
compressissimus V Orbigny - 142
conciliatus Stoliezka .........--- 107
couloni a’ Orbigny — : 4
ONES LLESULISUO MLC ZK On cteria sa sein = se leaps nie se lana laos 107
CRUE StOU CLR Ae ole acess eles on ae sae =~s 107
deciduus Hyatt Ete ty
CUNAUONUSC OUDIEN Yas .c2s~- = =0 52a e< =e 131, 186, 138
(ESP GIO 9) lah iaeke aaRes5s Sea AReacocBCOUe AOD ecao 141
domeykanus Bayle and Coquand..-...-..-..-----... 115
CRTOSUOUNUS Os OUDIEM Yim a2 os = 2-2 seme == as sical 139
CLOTIPNTIUS SUREDO ss = on apn sows ccisic wae ate eine ens 107
MU mVOUPBUCUE Essence: as anes nse nen ne sana S ;
OCLEMUS C: ORDISN Yoo. oon awa ensneese-nssne 135, 136, 142
GEUTIIOTHLR Gt OXDILTEV so e,- a2 ccc osicisejee sack cee eld 84,90
QUOC AIROCMCL 2. 2. ace wcwcecsn cesses -we= 197, 241
haplophylla Redtenbacher ..........--.-.---------- 48
ROM LULA RASY EGU) esas sco ate ws eos oie cielo nie mis ctclaieiaeraicle 103
heteropleurus (Neumayr and Uhlig)......-...-----.
laticlavius Sharpe - -
TOT AR LATS ONY CX cena dle oars eeenia ais ceca ees see 7
TAUOA CIRRBT SECON atalas ora rats co's anise sis 'clone vine cos /ee@yens
VOD CEUIOMG Ye esac te = 0-2 = oleate ma sro saan = aia
CERN UI ULE te CAC Ct SOROS JOBE SIO I ROR EC OE 108-110
MLOMUMULOLUS) 2 amie jaan = == 3 ese oe P panonoaoeneactaas 108
MOMLCUB SOW CL DY - =< = v= == sees aapesiawae ss 114, 115, 141
TUT COMBO NUS CLOTDIPNY,- =< ssaeecesscn-=sscsccer sos 90
ON EL TOUS ERT eS se ARES O SCD OR AISCSUCE BOARS OOOCSE 239
MOSES CHOLDIC IG = <2 canoes selenite nee cemciamas 84
Miss OA OLDIP DY seen soe cen sss ccicien= see emes 100
nodosoides Schliiter
orbignyanus Geinitz
pedernalis ROEMEY <<. - Joc. --so=-0- 59, 6
’
figures in black-face type are numbers of pages on which descriptions appear; figures
Page.
| Ammonites—Continued.
Pi CEUis VOUIs UCM senses cssecec sas aeeeenee ns 157, 165
plocentaiDekay Sapa s-bsoscccenc-as ecco sees eee 211
plewrisepta CONTBG:. 2s - «22-2222 son -omce oe 5 i)
polyopsis Dujardin. .........---- E-8 240, 243
provineiaisid’ Oxdignyicc cc. = sae eee ae eee eee 5d
coronatoidies=).--- s--- eee th ee 130, note neoceratites Peron sacs. occe sn cee eee a ee 55-56
Gosmoceratida ere ee eee 1012105) || Hoplites pees eee eeereee ee 2 101; 130, note; 193
Gretacicnuse ob tenmiee. -ss-c- 52 eee te ees 11 IO plitifOnM IS esate see see eee eee ent 181, note
Desmoceras Oe osataae seers eee a eee 101, note Splend ensho=. aoc aio enantio acta a te oe ee 192,193
Desmoceratidee 2.6 sess - 2 ow sows qe es osaesisesse ee eae 25) MELOp]Itid topes ao eens oe eee cies ete oe 105; 131, note; 137,192
Development, acceleration and arrestation of. 19-23,189-190 | Horizons, table of........-...-.-- Bre EGE AaOIORS HeeSIS 18
Diadochocerasibivaties-esseceee eee ae et TOS 1065107) | Poy perlioceras!/discoldtm nessa nan al ee eee eee 19
nodosocostatum)-c-ee eee eee eee eee eee seers 106, 107 SUDGISCO IG Umer ee eee se meee eeee ee ees 19
Diplacmoceras Hyatt=2-e---------5--------= 189, 192,'242-949' | Hystatoceratidee... =< os ooo oie wee ee 24, 26, 27
bidorsatunnl (ROemen\pess os. eecekeee ee seenee eeeeae 248" |*IndocerasiNoetling onan. soe eects eens 56
ecanalicnlapumibivattjescc -fo.206-se- sense eee 243-944 acutodorsatum (Noetling) ........-.-..-.--..-...-- 57
Douvilleiceras Grossouyre. -- 105-107, 108-109, 113 baluchistanense Noetling...............-:-------- 56-57
mammillare!(diOrpieny)=---- 22 ceases eee eae 109) 113) |) Kevemiceras Bohm eee n emcee ecm mate 26,30, 145, 192
OYDIGM YUE Abbe eee ne oes scree see eee 110 attenuatum (Hyatt) ..-...5..........-... 33, 151, 152, 286
Bpiniferum(Wihiteaves))ssa..cs--- sso e eee 110 compressum Hiyatt..-----..---------..- 149-15), 152, 284
Echinoids, parallelism in local development of -..---- 195 var. subcompressum Hyatt......... 149, 150-151, 284
Pngonoceras NeumMayr. =<. once ec een een e cena ces 20, 21, 58, PEN US hE ee Sameooconsosbe SneSs onde scoot esoaeaS 152, 288
145, 147, 153, 156, 157-158, 178-180, 182, 196,1 2 syriacum (von Buch) ...=.-.-..-..-.... 146-149, 150, 254
belviderense (Cragin) 158-159, 258 whip (Chota) faassen eee a 152
complicatum Hyatt ...-- SPASM ASO) exe TN) C@Ne UO ee ere iene mie eee reals teeta te ae ei 144-152
emarginatum (Cragin).............-.-.- .. 159,160,177 | Lenticeras Gerhardt..-...-..-..--- 22... ------s0--- 84-85, 103
gabbi Bohm | Pie co sescnsesseaocr os seessoctoobentacorosSsooc 84-85
gibbosum Hyatt IMeiayn(Gen (NG Foe SSS necmobe -cmeacosesoaasaosatcoscds45
inscriptum -.-. TE eyrolerMechen dls - eee on Goes Sere cee anes soo-Secissnonds
pedernalis Bohm ..... Libycoceras Hyatt
pierdenale (yon Buch) - ismaele (Zittel)
var. commune Hyatt Lophobolites Hyatt
retardum Hyatt. - cotteaui (Nicklés) 144
roemeri (Cragin) ...-- Mammitida 24,27; 101, note; 109
serpentinum (Cragin)... Nitrate Hopsee =A 5 Se ean Ak eos sooseessogs=sans 36-0 24
stolleyi BGhm.........-.. Mantellicerastely atte asm -cmesss-emeee esse 110, 111, 118
subjectum Hyatt.....- 58, 161, 164, 168-171, 294, 296 COULOTIE (QLOLDIEIY)) ee wetness ol oer 114
middeni(Gragin)pss-s-eeeee eee 154, 158, 159-161, 175, 290 domeykanum (Bayle and Coquand) ....-..---..-- 115
Engonoceratid@...-~...-------2----- 144, 145, 153-187, 193, 243 INICIAN PSC Ie y ena eee eee ase ace eee 115
Erymnocerds' 2: os scenes scene eae a sae 102 mamntelli (Sowerby). ---.--5------2e2-5--5-0™ 111, 118, 114
Bulophoceras Myatt 23. ssa. sn as oe aise 83-85, 100 picteti Hyatt -.. 1i4
Matalensesdratte sacs itee seater ree 86-87, 274 UISHAS (BS LOUCZ Ke) emi = cement ee eee 115
Hulophocerdtidee ec se as-is tanec eeeine 24, 83-87 VICI AEN ( SUOLCZE)) teens) totais ae tele ae ere
Families, classified list (Of=.- 22s. 2-=-te-0 4 =-se= = - === ~= 15-18 | Mantelliceratida ......
Gabbioceras batesi (Gabb) . Mantelliceratide ........
Genera, classified list of ..... 2... ----teeeccercee--oese= Metacanthoplites rhotomagensis (Defrance).........- 107
INDEX. 349
= Page. Page.
Metasigaloceras Hyatt. ...............c.scc- ces eeececee 106 | Pedioceras Gerhardt ..............csee-cneerce-n- one 105, 108
WHBULCNIN (SOWELDY)) asc. -a-(caaceeeaaccp ona cunt 106 caquesensis ... 107
A VAMISSODIAI EUV EDU ito ceie.scicisie eb sietesia sieeve ceisirs 43, 45, 50,55 cundinamarese 107
MULENSGDEIe UE CTOD ccc seeeerieeuasaeesseamriaes are 49 MDAQUCHKIS!. oes as osesniee nrwinimn' sain 107
poe ld GROLMMBS UCN. erecta cae cele enieieiseciinsesaieale coe A87D2 a PCGlOCOrauGee tcc sence ce tesecoce aes asec 105
FORUTIGL UM IGA VLE) [accel cic meals acne ote epee oe coat 45480 ePeroniceratides,4--2--/.22s-+esasbieseeessenen. - 24,27
haplophylla (Redtenbacher) .........---..-..-..-- S30 MPUTICODOCCKBS a viewe on co cesses sake aan eeciccev em em 105
TCL OME eu Uta nics nicl ole sine nin nos clememinsiemasscew 46,47,48 | Phyllocampyli.....-....---..----20-seeeeeeeceeees . 25
ODI (ROIOLIOTS)| \oin/a a's oi ew o.n'cseee sess es 45, 46-47,48 | Phylloceras..............- BOR CHS Sea Shone eee 76, 88, 234
BH ZEWICZIU EMAL OU) atc cic = Ssicdinia sels o'wics seme eects 4973) Phylloceratidse te. -2-2---222> saclaeece cesses eo 100; 101, note
Metengonoceras Hyatt............. 153-155, 15 ,L79-180 | Placenticeras’ Meek. ... 2.2.2... 50 - once eccnwenncciccenen 20,
PAC EAGUIINEUMEUU Wis: «1c sisle wlvie ate a'n-1e' «eo es 184-185, 187, 304, 306 22, 94, 140, 145, 158, 155, 178, 185, 188-196, 243, 244
AL LSU EN LGU arn siecle nae ala a= oc wlaisinic lace 1838-184, 304 CalifomiCim eres ctenrisesscelewec semen cieeenib ncn 192, note
Gum bu (Gracin jess s-cse2 cc sce eecaseee 180, 185-187, 306 Crnssatum Vata scccesses sceecs sniee= ee aaoeen seer
inscriptum Hyatt .............. 180-183, 184, 185, 302, 304 Gepressum Hyatt... 2... 2.22. e en econ ceene
Metoicoceras Hyatt .........-.- 101, 110, 118, 116-117, 129, 134 ebrayi (de Loriol)..............-----002---22---<
ACCOLETALUNINELV ALL cremate diciasisecisice'smie cis sas 127-128, 280 fallax Castillo and Aguilera
RipbosumMPMyath. c=. s.. cece ccm on cclaccoe 121-122, 282 Prischtt| GLOSSOUVTGl «2 2 eines loess neice ncelswse aie
HIT HH EAN CVEL OTIS mio «.w cjaiste owiclnciniea sini s~ icine sle'ais ees PTOSCOUV TOL ELV Et iien ocisi- o'sleiveeleicieieeiseiele 190, 191, 237-2388
Ballo (Shumard))occcenes-sscececateancaciace cece | guadalupz (Roemer) .......-....---------+- 188-191, 196,
23, 134, 274, 278 197-199, 200, 202-204; 206, note; 211, 213, 2:
WIRItCL EUV AUb ne nis cece cce 118, 121, 122-127, 128, 278, 28 GNCIRMIM EV Abbie cei tceiewiek se Seca ae tease seiesine
Web oICOCETE WO ce nea snemniiae sam anecic anon acnecfemce acs 115-128 intercalare Meek... 90,
Mojsisovicsia Steinmann ....--..........- 24-25, 26, 27, 89, 90 , 221, 322-330
durfeldi:Steinmann. <...-))..-.--2-se. es 5e---5 25-26, 254 TENTICULOT CNNCO Kia eletciatala ors = wlowc ise neta wieiciein' sine = 71-75, 242
IMOjSsisOWicsli dee Myatt one. ccc cee cc aceeicc since = set's 24 liardense WHITCAVCS= << --.- = a0 c2 ewes oee ne nen nancies 127,128
INGOlODItESRISCH ED: cnc enlace = - sense eel 58, 104, 144, 158, L78 memoria-schloenbachi Laube and Bruder.....-.-. 236
GHOMADIBE VEL ite eee ete eee =m eine ean hclee =n 178, 302 moillerti((Hauer)\essss- as cesce ese ces esate 190, 191, 238, 239
CUMEORLIBNGA GROG ero! te cere a oisiccan See odes anew ele 144 newberryi Hyatt . .. 190,191, 196, 200, 2038-205, 206, 314
MIELOMIMLU VE Gloss metacsie cto cinicts. ac eetisiccece as eae tce 179 orbignyanum (Geimitz)\ so sess
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