March

70 [March,

Descriptions ofnew_sjjcciesof GasteropodaandCephalopodafrom^theCretaceous for- mations ofNebraska _Territory^.

By

^{F. B.}

Meek and

F. V. Hayden, M. ^D.

TuRRiTELLA CONVEXA. Shellacutelv couical; rolutions flattened convex; su- ture linear, indistinct; surface

marked

with fine lines of growth; aperture ovate, acutely angular above, rounded below. Length

unknown;

^breadth of largestspecimen^.39inch; apical angleveryconvex,divergence

20.

This _species

may

^{atonce be}distinguishedfrom any^othershell

known

tous from this region,by^the convexity^{ofthe lateral} slopes ofthe _spire,

and

the absenceof revolving^lines.

Localityand_position.

Yellow

Stone river,one

hundred and

fiftymiles from mouth. No.4of theseries.

TuRitiTELLA MoREAUENSis. Shell terete; spire elevated; volutions

(number unknown)

flattened,increasing very gradually from the apex,

and ornamented by

elevated thread-like revolving bands orlinesaboutequal the intermediate spaces; while sharply elevated, regular,

and somewhat

distant, linesof

growth

traverse thewhorls fn the other direction^: suture linearand sharp; aperture subquadrate, forming nearly a right angleonthe inner side above,

and

termi- nating^{in adistinct} notch on the columellar side below. Length (unknown,) breadth .10 inch; length of aperture^.07 inch,breadth.04 inch; apical angle regular,divergence ^9".

We

have_onlyincomplete specimens ^{ofthis species,}consisting offromsixto eight volutions, of

which

there were probably^{not less} than ten.

On

the last whorl, there^is a fourth smaller revolving^linebelow the others,

and

still lower, severalvery^finerevolving^stria;.

The

linesof growtli, are

much more

^distinct between, than

upon

^therevolving^linesonallparts of the^shell.

Localityandposition.

Moreau

river. No. 5oftheseries.

Belmnitella? bulbosa. Shell elongated, cylindrical,widening ^{at the} open- ing,then

somewhat

contracted,

and

_{again enlarging} belowthe middle,

whence

itgraduallytapers^to a point; alveolus having^{a small} groove

down

the dor- sum,

and marks

of transverse septa round the sides; substance of the shell fibrous, fibersradiating^at nearly right anglesfrom the central linear axis to the exterior.

Phragmacone

tapering regularly at an _angle of 20 from the larger extremity^to the apex,

where

itterminatesinaminute but ^distinctbulb- like expansion; ^{section circular or} broad oval, septa faintly sinuate on the

dorsum

and separated

by

spaces equalling about one-sixth the diameterof the shell; about twenty-eight ^{of the} septa

may

^{be counted in the space of half} an inch from the apex.

Length unknown

; diameter _{of largest} fragment^.33 inch.

We

haveof this species perfect specimens ^{of the} phragmacone, but having onlv seen longitudinalsections, and

worn

_fragments ofthe externalhorny^shell,

we'know

nothing^{of its surface} markings, nor whether^{or notit} possessed the longitudinalslit'characteristicof the genus.

The

_groove

down

the inner side of the alveolarcavity, however,^iswell

marked

in

some

of the fragments.

We

were

atfirst inclined toreferitwith doubt to Belmnitella

mucronata

_(D'Orb.)

which

has already received such a multiplicity ofnames, but ^{a careful}

com-

parisonwithauthentic specimensof that speciesfrom

New

Jerseyconvincesus it is different,

and may

^{be at once} distinguished by ^{the small} bulb ^at the apex^{of the}phragmacone,

which

_alwaysleavesits impression^atthe point of the alveolar cavity.

So

faras

we

_know,thisgenusis,inthe old world, confined^to the true chalk.

Localityand_position.

Moreau

river. No. 5of theseries.

Ammonites

^halli. Shell large, laterally compressed, rounded on the dor-

sum

; umbilicus rather small, deep,

somewhat

funnel shaped, exhibiting one- third to one-fourth, of each of the inner volutions; surface

ornamented by

numerous

small, slightlyelevated,costie,

which

cross the volutions

more

orless obliquely.

About

one-fourth of those crossing the

dorsum

reachthe umbilicus,

185G.] 71

aroundAvhichontheouter_wborl,they ^swelloutinto a

row

ofprominent^trans- verselyelongated nodesor ridges,whiletheinteimediate ones_{die out,}orcoalesce Aviththeothersatvarious distances acrossfrom the periphery.

Septa profoundlylobed,

and

exceedinglycomplicated. All themargins^ofthe branches of the lobes, sharply,

and

those of the saddles obtusely, digitate.

Dorsallobe

ornamented

atthe extremity withfour principal branches, the

two

terminalof

which

_{are larger}thanthe others,

and

_againdividedinto

two

branch-

lets. Dorsalsaddle

much

_largerthanthe superiorlateral lobe,incqually divided at the

summit

_bythe slender digitate auxiliary lobe into

two

branches, thaton the dorsal sidebeing

much

_largerthan_{the other,}

and

again once^{or twice}dyeply divided. kSuperior^laterallobe

much

smallerthanthe dorsal saddle,

and

_having four principaldivisions,the

two

terminal of

which

are greatly larger thanthe others,and each again^dividedinto

two

branchlets, of

which

the

two

lateralare

much

smallerthanthe others. Superior^{lateralsaddle a littlesmaller}than the superior ^lateral lobe, deeply ^{divided at the}

summit

into

two

nearly equal branches, each ^{of the divisions} being again^{divided into}

two

or three parts.

Inferiorlaterallobesmall

and

slender, having^{four orfive}alternatingbranches.

The

_succeedinglobes arevery^small and simply^{bifid ortrifidatthe} extremity.

It isexceedinglydifficult, ifnot impossible,from our_imi)crfectspecimens, ^to determine_definitely whetherthisis Scaj^hileoran Ammonite, though

we

arein- clined, in consequence^ofitslarge size, tothinkit

must

be thelatter.

Our

de- scription^is

made

outfroma

young

^shellmeasuring^four

and

ahalfinches across the_disc, while\y&have fragments^of other individuals

which must

have been atleast four times as large; hence

we

_infer,in adult shells of large size, the lobes of the septa

may

have been even

more

complicated thanthose of the spe-

cimen

investigated

hj

^us.

From

the

same

bed

we

havea large distorted specimen, apparently ^{of the}

same

_species,

which

islesscompressed

and

has _strongercostae. Italsoappears to

want

the

row

ofnodesroundtheumbilicus.

As

faras

we

have beenableto seeits septa,they appear^tobe identicalwith those of theabove _species; con- sequently

we

are disposed, at present,^toregard ^itas only a variety of thesame.

It is possible,however,^a careful comparison ^{of better} specimens

may

prove

them

tobedistinct;if

so,

we would

_proposeforitthe_specific

name

_{of ampins.}

This_speciesis

named

after

Prof James

_Hall,ofAlbany,^N.Y.

Localityand_position. Yellow-stone _River, one

hundred and

fiftymilesabove the mouth,

and

one

hundred and

_fiftymiles above Milk_River,No.4ofseries.

Ancvloceras?

Nebeascensis.

Of

thisspecies

we

have butafragment,^.about

two

inchesinlength. ^It

makes

a shortspiralcurvelikeHelioccras (D'Orb.)

and

is ornamented with small (bifurcating?)annular _costje,

more

distinct on the ventralthandorsalside.

The

_specimenistoo imperfect^to

show

the detailsof the lobes,though

we

can see they^are verycomplicated,

and

_sharplydigitate.

Section _circular,diameter.90inch.

This andthe following species

would

notgo ^intothe genus Ancyloceras,^as defined

by

D'Orbigny, but appear^tobe closely related to foriBS,so referred

by

Pictet

and

others.

Locality. Iquorcreek,north _fork, Cheyenne. ^Position. No. 4 of theseries.

Ancyloceras?

Cheyenensis.

The

_{only specimen} ofthis species

we

have seen,^isa.section of the outerchamber, about

two and

a half inches long. ^It

makes

abroadspiralcurve,

and

is

ornamented by

prominent

rounded

annular costsR,

which

encircle theshell veryobliquely,

and

are smallerand

more

_ap- proximate on the inner side of the curve, than without. Costre having

two

prominentnodes,^at

which

_pointiAiQjsometimes bifurcate; the nodes being ^so arranged^astoform

two

_parallelrows

up and down

the dorso-lateral portion of the shell. Section circular,diameter2.40inches.

The

above _species

resemWes somewhat

Ancyloceras? ^{Nicolletiiof Hall}

and

Meek

_(Vol.5,

new

series.Trans.

Am.

Acad. Arts and Sciences, Boston,)but has

much

_larger

and more

_{prominentcostre,}

which

_passlessobliquelyroundthe_shell,

and

do notbifurcate so frequently,whilethenodesare_larger,

and

thecurveof the

70 72 [March,

shell

much

broader.

From

Aocyloccras? aproximans, Con. (Proceedings^{of the} Phila. Acad._p.266,) itdiffers inhaving broadly rounded,^{insteadof acutecostae-.}

Localityand_jwxilion.

Mouth Cheyenne

^{river. No. 4.ofseries.}

notices of remains ofextinct ReptilesandFishes, discoveredbyDr.F. V.Ilaydcn^inthe

Bad

Lands_oftheJudith_River,Nebraska_Territory.

By

^JosephLeidy, M. D.

1. Pal.bosciscuscostatus, Leidy.

The

_{genus andspecies}ai-efouudedon_{a single}specimen of a toolh of a lacer- tian, discoveredbyDr. Ilayden.

The crown

of the toothis palmate,witheight radiating^costfeterminating^at themarginⁱⁿ

more

orlessdevelopedpoints.

The

_fangis flattened cylindrical,

and

ishollow;

and

itexpands^intoa ridgesurrounding ^thebaseof thecrown.

Breadthof the

crown

4_lines,length 2i^lines; widthof the fang2 lines,thick- ness 1 line.

Whole

length of the specimen^4lines.

2.

Trachodox

mirabilis,Leidy.

The

_genus

and

species arefounded

upon

specimens^of teeth,generallyvery

much worn and

inafragmentarycondition, of a herbivorous lacertian _reptile allied tothe lyi/anodon,discovered

by

^Dr.

Hay

^den.

One

of thespecimens^{of teethis}an

unworn

crown, about^14lineslong and ⁵ lines indiameteratitsthickest_part. ^Ithastheformof a_slightlybent hexahe- dralcolumn,^{bevelled off} convexly from ^the

summit

of the tooth internally to thebaseexternally.

The

outer surfaceissmooth,

and

hasaprominent

median

ridge

and

prominent subacute^{lateral borders.}

The

inner surface of the tooth, presenting the^five smallersidesofthecolumn,^is_quiteroughened with irregu- largranulations. ^Tliebaseof the toothishollow,

and

its wallsat the broken borderofthespecimen^are IJ lines thick.

Lianother

and much worn

_specimenofa_tooth,

which had

apparently been shed,

and

is

now

_4^lineslong; the triturating surface ^isslightlyconcave

and

pentahedral,withconcave sideS,

and

is 4lines in diameter.

The two

_portions of the outer surface incline

much more

fromthe

median

_ridgethanin the pre- cedingspecimen;

and

the baseof thetoothis hollowed, apparently from^the pressure of a successor.

3.

Troodon

_{pormosds,Leidy.}

The

_genus

and

species arefounded on_{a single}specimenof a tooth of a lacer- tian,discovered

by

^Dr.Hayden.

The

_specimen consists of a compressed, curved, conical

crown

with tren- chant_edges.

The

outer side is

more

convex than _{the inner,}

which

is

worn

offtowardsthe apex from ^{frictionof the}opposing^tooth.

The

trenchant edges are coarsely denticulated; the denticulations themselves being compressed conical,^witlitrenchant _edges,

and

are bent insucha

manner

thattheir apices aredirected towardsthe

summit

ofthecrown.

The

baseof thetoothishollow, andis2 lineswide

and

1J^linestransversely;

and

the length of thespecimen^is 3 lines.

4. Deinodo.v horkidus,Lcid}'.

This genus

and

species are founded ona

number

ofspecimens,consisting of fragments of teeth of a saurian_reptile, discovered

by

^Dr.Hayden.

Nineof thespecimens^{referredtoconsist of}crownsof teeth or oftheir

sum-

mits,

which

resemble those of Mcgalosaurus, being compressed ^conical

and

curved,and having trenchant, dentatcd borders.

They

^are generally thicker inrelationtotheirbreadth thaninMegalosaunis,

which

_{might only be a}specific distinction,wereitnot that there are several other teethⁱⁿthe

same

^collection apparently^ofthe

same

_animal,but_{quite peculiar}in form.

One

ofthespecimens^isa curved conical crown", nearly circularⁱⁿtransverse section,having^aprominent dentated ^ridgeon each side.

A

second specimen

isacrown,deuii-elliptical in transversesection,withthe posterior bordersden- tated.

A

^third _specimen^isasmall fragmentof a very large tooth, apparently