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ON

THE SILURIAN GASTROPODA AND PTEROPODA

GOTLAND

BY

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G LINDSTROM:
AANA

WITH TWENTY ONE PLATES.

SMITHSON Ay
APR 18 1985
LIBRARIES

STOCKHOLM, 1884.
KONGL. BOKTRYCKERIET.
Pp. A. NorSTRDT & SONER.

GRESOE LTS Vet Mol, Mod
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LindsteOm , Gustaf, Moana! ht Afisl&

On the Silucr rian Gastropad ae
Preropade. of Gotland_

| Gfoekholm t BA, Norsted , 16¢eY

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CHRARAES

INTRODUCTORY REMARKS.

If, in general, it is a hazardous undertaking to describe palwozoic fossils, which,
us a rule, have only a few recent congeners, with which to be compared, it is the
more so in regard to the fossil Gastropoda. Every zoologist is uo doubt fully aware
of the great difficulties, that surround his investigations, whenever he endeavours to
make out the affinities and systematic place of fossil Gastropoda in general, and espe-
cially so of those of the palewozoic era. There is indeed not much in the often distor-

ted shells to guide him. The microscopic structure — if there ever has been anything
characteristic in it, which so seldom is the case even in the recent ones — is almost

invariably destroyed or changed into a homogenous crystalline, calcareous spar, nor
are there usually any traces left of the muscular impressions, which are peculiar to
some few families. Moreover, what the naturalist in his study of the fossil shells has
to grapple with, is the same as if he had to describe recent shells only from bleached
and worn specimens cast ashore along the borders of the sea. There is indeed often
evidence that several of the Silurian fossils of Gotland and consequently also the sl:clls,
had been rolled and tossed about in the sea before being embedded in the strata,
which, according to all appearance, are nothing but beaches or deposits in shallow water.
Moreover, when once fossilized they have of necessity shared in the vicissitudes, which
afterwards befell the rock through metamorphic agencies, being changed as to struc-
ture, often deformed through pressure as to their exterior shape, worn and eroded,
and consequently deprived of the fine ornamentation of the. surface.

In almost every instance, the investigator has thus only the external shape of the
shell, as it is, whereupon to found his conclusions, and we know how very little the
empty shell informs us regarding the real nature of the animals, and how delusive,
even amongst recent forms, the exterior shape can be. It may here suffice to cite
an instance lately brought forward by J. Carriere.

In a paper on »Marginella glabella L. und die Pseudomarginellen»’) he relates
his observations on two species of Gastropoda belonging, according to the structure of

1) »Zeitschrift fiir wissenschaftliche Zoologie Bd 37, 1882, p. 99.

4 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

the mollusca themselves not only to different genera, but even to different families.
They had assumed, as it were, exactly the same sort of investment or shell as the true
Marginella glabella, only differing in trifling and easily overlooked details, so as to

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have been considered till now as of the same species as the last mentioned. What in
reality are three different species, not even appertaining to the same genus, nor to
the same family, had thus been regarded as one and the same species, until the ana-
tomical structure of the animals revealed their fundamental dissimilarity.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. 5

In spite of the certainty of many unavoidable failings and shortcomings, which
as pointed out above, follow from the nature and conditions of the material, I ventu-
red to take up this study when it was found how unexpectedly rich and varied were
the forms entombed in the Silurian strata of Gotland, and thanks to the munificence
of the Royal Swedish Academy of Sciences it has now been brought to its conclusion.
Though fragmentary in many respects this memoir may serve in some degree as a star-
ting point for future labours in the same field.

Silurian strata of Gotland.

Before entering any further into the minor details of the composition of the
Gastropodan Fauna, it may be proper to survey the physical conditions, in which
the shells are found, as the strata, rocks and localities and also to inquire into their
general faunistic characters. Through the classical researches of Hisiycrr the general
features of the geological constitution of Gotland were very well known; but it was not
until the visit of Sir Roprericx Murcuison to the island in 1845 that the position
of its strata was interpreted according to the researches, which were then carried on
in other parts of Europe and especially in England by Murcuison himself. After a
stay of a few days, chiefly on the west coast of the island, he proclaimed the strata as
Upper Silurian and arrived at the conclusion that they were to be subdivided into
three groups, corresponding to the English Wenlock, Aymestry and Upper Ludlow, and
that in fact the southernmost point with its substratum of sandstone was the youngest
division, in direct opposition to Histvcer, who considered the sandstone as the oldest
of the whole of the strata and underlying them all, though hidden from view north of
Bursvik. The conclusions of Murcuison were adopted by Frmepricn Scumipt, who fol-
lowed up his researches and gave a more complete description. He also divided the
island in three groups: Northwest Gotland or the Wisby Zone, Central Gotland and South
Gotland, subdividing the second or Central Gotland in two beds, that of Pentamerus estho-
nus and Pent. conchidium, a division which cannot be upheld as Pent. conchidium oc-
curs beneath P. esthonus as well as above it and moreover is restricted to very narrow
limits within the large zone he has assigned to it. He assumed the strike of the strata
to be N. E. and S. W. and their dip consequently from N. W. to S. E. His three
groups form oblique belts across Gotland. He, as well as Murcutson, had only paleon-
tological evidence to adduce in favour of his opinion. Murcnison’s, and consequently
also Scumipt’s views have been contested, amongst others by Ferp. Roemer and Hert-
MERSEN, and it is highly probable that their mode of viewing the stratification of Got-
land is more consistent with the real state of the facts than that of the former geo-
logists. As Rormer and Hetmersen have already demonstrated, there are neither stra-
tigraphical nor paleontological evidences to support the views of Murcutson and Scumipr.
If, as the latter authors hold it, the shale along the west coast of Gotland belongs to at
least two divisions, namely the beds around Wisby to the Wenlock shale and those south of
Klintehamn to the Lower Ludlow, the superposition of these strata above each other
must of necessity be seen somewhere. But as to the shale beds of Wisby they can be

6 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

followed without interruption all along the coast from Hallshuk, in the north, to Gni-
svard, south of Wisby or for a length of nearly 6 Swedish or 386 English miles. At
Gnisvird, where the fossils are already, with regard to several species, identical with
those found plentifully at Westergarn, the strata are obscured for about an English
mile and a half by accumulations of sand and then again the same shale beds reap-
pear horizontal as before and continue with a few breaks to the vicinity of Klinte.
It is highly improbable that there should be any traces of superposition of the strata
of Westergarn and Klinte above those of Wisby on the narrow belt covered by the
drift. The shale beds of Westergarn which have so much in common with those of
Wisby are combined with the shales of Eksta and Habblingbo through the shale beds
of Stora Carlsé. As I have shown in a former paper’) the beds of Westergarn and Stora
Carlsé are absolutely identical, having not only a great percentage of species in com-
ion, but these species are also of exactly the same varietal habitus. Further, there
is no doubt that the shale of Stora Carlsé is in direct continuation with the shale of
the nearest, opposite shore of Eksta and that this again is combined with the shale of
Habblingbo. We have thus a continuation of shale beds along the coast for a length of
nine and a half Swedish miles or 57 English ones. But these beds spread also, as can
easily be seen in numerous sections, far inland under the limestone beds. The shale of
Petesvik in Habblingbo can be traced from the shore upwards for a Swedish mile, to
the saw mill of Alfva, having there reached a height of 80 feet. Quite the same sort
of shale is again met with in Fardhem, where there are sections in several places
and the shale retains nearly the same palwontological character as at Habblingbo.
The same form of Rhizophyllum Gotlandicum has been found in both localities.
But in Fardhem the shale begins to contain particles of mica and quartz in greater
abundance than elsewhere and in fact partially to change into something intermediate
between shale and sandstone, and this gradual transition can be followed, as it were,
step by step aloug the road leading from Fardhem to Rone where the lowest stratum
is found to have been completely changed into sandstone. This predominates along
the shore towards the north for nearly three Engl. miles, now and then changing into
patches of shaly limestone and at last passing into shale, as I remarked as long since
as 1857°). South of Rone, again, it is connected with the sandstone beds of the southern-
most Gotland. The sandstone beds there and the shale beds of the north of Gotland
thus belong to quite the same geological horizon and gradually pass into each other.
But, as now the shales of Central Gotland lie under the hills of Klinte, Sandarfve and
all other limestone beds there, the limestone hills of Hoburg must be considered as
detached outliers of that central limestone plateau, with which they have in common
many characteristic fossils, though separated from it by a wide region, where the upper-
most beds have disappeared through denudation. A distance of nearly four Swedish
miles intervenes between the northernmost hill of Hoburg and the nearest point north-
wards near Burs church, where the limestone is again found. Between the lowest stratum
of shale and sandstone and the uppermost limestone, commonly called crinoidal limestone,

') »Anteckningar om silurlagren pa Carlséarne» i Ofvers. Vet. Akad. Férhandl. 1882, nr 3, p. 5.
*) Ofversigt Vet. Akad. Forhandl. 1857, p. 33. »Till Gotlands Geologi».

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. I9. w:o 6.

~]

strata of thinbedded limestone and shale are interposed, north of Grétlingbo and Rone, and
they pass gradually upwards into the more uniform, hard crinoidal limestone. In the South
of Gotland again, wherever the sandstone prevails, the intermediate stratum is oolite.

According to what has now been adduced, we have, from their petrographic cha-
racter, three strata viz.

1. The oldest shale or sandstone stratum, in the following signed a.

2. The laminar limestone, intermingled with shale in the north, beds of oolite or
pisolite in the south, signed 6.

3. The highest limestone; covering all the other strata, signed c.

Along the east coast of Gotland this succession of the strata is somewhat ob-
scured through frequent dips and contortions of the beds. In how far these three
different strata can be well distinguished by their faunas, is at present, when so few
groups have been monographically worked out, too early to decide and cannot be finally
settled until the rich Silurian Fauna of that island will have been described through
all its classes.

Regarding the chief characteristics of the different strata the following remarks
may serve.

Stratum a. The thickness above the sea is extremely variable, owing to the
many curvatures and domeshaped folds into which it has been thrown. Near Halls
huk the shale is 50 feet thick, in Fardhem at Burge again it is found at 70 feet
above the sea level and at Alfva saw mill even at 80 feet. But it is probable that
its total thickness is still larger, as shale beds are met with in Follingbo at a height
of more than 100 feet. The bottom of the harbour of Wisby at a depth of 20 feet, has
been found to consist of shale, and consequently this rock attains there at least that
amount of thickness below the level of the sea. Owing to the curvatures in this
stratum it is, however, very questionable whether these 20 feet are to be added to
the amount found in Follingbo. The sandstone south of Bursvik is not by far so
thick, only 20 feet at the most. But the mass hidden in the sea is probably far
thicker, as, owing to the southeastern inclination of the strata, only so little is visible.
Fossils are found cast ashore on Norderstrand near Wisby, enclosed in a soft, red
marly limestone. They are partially of the same species as in the gray shale but also
of characteristic forms. There is a low depressed variety of Goniophyllum pyramidale,
Phacops elliptifrons, a small Camerella, but also Arachnophyllum typus which never
occurs in any higher stratum. This red marl is in all probability the basis of the oldest
and lowest shale beds of Gotland and to be found in situ deeper in the sea, from where
fragments are thrown up. Hitherto the oldest shale beds have only been found north
of Wisby. Through the presence of Stricklandinia lirata, Euomphalus Gotlandicus, Pleu-
rotomaria qualteriata var. and a species of Harpes, only found there, they announce
their age as Upper Llandovery. Stricklandinia does not occur higher up in the shale
beds. The beds above its zone, as well as the sandstone in the south, may be regar-
ded as of Wenlock age. Sections of this stratum are also seen in several places on
the east coast of Gotland as at Slite, Ostergarn, though mixed up there with bands
of hard crystalline limestone.

58 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Fossils have been found in the shale and sandstone beds, which long had been regar-
ded as distinguishing the Upper Ludlow rocks. Such are Phacops Downingiw, Homa-
lonotus ete. But this must not detain us any longer, as also in England, according to
the last editions of Siluria, the Ludlow beds have very few species, which are not also
found in older strata. Homalonotus and Chonetes striatella, once supposed to be so cha-
sacteristic and exclusive, are now also found in the lowest Wenlock beds, both in England
and Gotland. It cannot, however, be denied, that there are many circumscribed fau-
nistic areas, as for instance in the shale along the west coast from Westergarn to
Petesvik, including Stora Carlsé. Within this region there can be discerned at least
four different facies in the distribution of the fossils, of which I have given detailed
lists in the paper above cited"). Although there cannot be the slightest doubt that the
shale beds of all these localities, as stated, lie on the same level and are coéval, the
strange fact is obvious that the beds of Stora Carlsé have a fauna identical with the
shale of Westergarn, which is a Swedish mile and a half distant. The fauna of Eksta
at Djupvik is distinct with regard to its composition as well as its features in the
common species, from both Westergarn and Petesvik in Habblingbo, but farther inland,
at Fardhem, species from both Habblingbo and Eksta meet in the same bed. So again
the fauna of Westergarn is distinct from that of Wisby, though both have species in
common not met with anywhere else, as Leperditia Hisingeri, Lindstrémia Dalmani,
Oriostoma Roemeri and others. But, upon the whole, strange as such differences in
nearly situated localities may seem, when they cannot be accounted for through
changes due to time, they may, nevertheless, find their counterparts in other strata, as
well as in the sea as it now is, where differences in depth or in the mineralogical nature
of the bottom, cause contiguous regions of the littoral belt to differ in their faunas.

Stratum }. In northern and central Gotland a stratum of thin limestone fiags
interstratified with seams of coarse marly shale succeeds the stratum a. It attains a
thickness of 70 feet, though at many points much less. Above the sandstone in the
south of Gotland this rock is changed into coarse pisolite or oolite with a thickness at
the highest of 20 feet. The change from limestone to oolite can be traced almost as
gradually as that from shale to sandstone. The banded limestone reappears above the
oolite in the section of Hoburg.

The stratum ec, commonly called crinoidal limestone, covers almost the whole
of the northern and central part of Gotland and, being denuded away over a large
tract, between Burs and Sundre, it forms again the numerous hills around Hobure.
Its thickness amounts to at least 150 feet, measured from the steep cliffs of Lilla
Carlsé, but owing to denudation it is seldom so considerable. The total amount of
the Gotland strata then ought to be about 340 feet. Now the highest point determined
lies 261 feet above the sea, according to Strmvmptz, near Rosendal in Follingbo, and
there are thus nearly 80 feet unrepresented at that point.

As may well be imagined, this uppermost stratum is highly variable as to its struc-
ture and organic remains. In some parts it well deserves its name of crinoidal lime-

') Silurlagren pa Carlséarne pag. 17.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6, 9

stone in consequence of its richness in remains of Crinoidea, chiefly their stems and joints
of stems. But in addition to this, there are also other beds of limestone, which from
analogous reason have been denominated corallian limestone. This, however, is only par-
tially true. With equal reason large portions of the limestone might be called Orthocera-
tite limestone or Bivalve limestone or Trimerella limestone or even Gastropodan limestone,
being then nothing else than a breccia of these shells. It is indeed singular that the
remains of one group of animals should predominate over all others in several beds.
So for instance the fine grained limestone of Follingbo near Wisby consists largely of
shells of Cephalopoda and the same is the case with the rich quarries of Samsugn,
where Cephalopoda, somewhat mixed up with Gastropoda occur in enormous quanti-
ties. In other localities again shells of the Lamellibranchiates are the chief components
of the rock. The largest of all Silurian bivalves in Gotland, Megalomus gotlandicus
forms in thousands of specimens extensive banks, that stretch from the shores of Faré-
sund in the north across the island to the immediate vicinity of Wisby and also along
the east coast at Ostergarn and along the shores south of that parish. The oolitic strata
near Bursvik contain almost only shells of Lamellibranchiates in great numbers of species
and specimens and a similar deposit of the same richness of identical forms occurs
further towards the north at Gothems hammar. At Bursvik and southwards to Hoburg
there lies along the coast a bank, half a foot thick, of Pterinea retroflexa and besides
several smaller.

Then there are localities where the chief mass consists of Brachiopoda, especially
of the genera Pentamerus and Trimerella, the former within more circumscribed limits,
the latter as a true rockbuilder across the island in a belt from north east to south
west. The occurence of the Gastropoda is given below. At first I shall only enume-
rate the different localities, where they have been found, with some few remarks
concerning the geology and paleontology of their strata.

Localities in the stratum a.

Wisby. Shale beds north of that town and along the shore to Halls huk and
round that cliff a small distance south in the bay of Kapellshamn, where they disap-
pear beneath the sea.

Gnisviird, a place south of Wisby to which the shale continues, rich in Brachio-
poda, partly common with Westergarn and partly with Wisby. A few Gastropoda
common with Wisby.

Westergarn. Low shale beds, uncovered along the shore line, rich in fossils,
finely preserved. Pleurotomaria labrosa and bicincta are often found here.

Stora Carlsé. The shale beds are well exposed along the east and west coast,
chiefly rich in Corals and Brachiopoda.

Djupvik in Frijel and Eksta. There is a long stretch of the coast comprised under
this denomination from the northern shore of Skiret in Fréjel to the shore south of

Djupvik, being of almost the same soft, blue shale filled with a large number of fossils
K. Sv. Vet.-Akad. Handl. Bd. 19. Nio 6. 2

10 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

of all orders. It is interrupted by the peculiar »caleareous shale» (kalkstensskiffer
Histycer) which, intermingled with sandy slates, occupies the shore around Skaret and
contains a great number of curious tracks, besides fossils of a fauna distinct from that
of the neighbouring shores.

Habblingbo. Along the flat shore of Petesvik a hard, blue shale, containing
more limestone than those in north, is spread out, filled with Brachiopoda and also
other shells. The highest point of this shale is further inland about one Swedish
mile, 80 feet above the sea.

Fardhem. A section of micaceous shale is seen near a saw mill at Burge
with fossils partly characteristic of Djupvik and partly of Habblingbo. Amongst the
latter may be remarked the interesting Rhizophyllum Gotlandicum. In the same
parish of Fardhem there is an extensive canal cut through a moorland, Wisne myr,
lying open a fine section of the shale for nearly half a Swedish mile. The fossils it
contains are very interesting, as species here meet with each other which were long
considered as exclusively characteristic of widely remote localities and thus give addi-
tional support to the supposition that all shale beds are coherent and of the same age.
Such are Phacops Downingix, also from the sandstone and oolite of S. Gotland and
from the limestone bed b of Wisby, Tremanotus longitudinalis also from Wisby a,
and the sandstone of Bursvik, Orthis canaliculata formerly from the eastern strata of
Gotland, Burs ete., Strophom. funiculata, the same variety as in Habblingbo, not Eksta,
Chonetes striatella, Pisocrinus ollula found in the shale of Petesvik, Pleurotomaria
planorbis His. which is so abundant at Ostergarn, the initial colony of Labechia or a
kindred coral quite the same as that found on the same level at Slite.

Bursvik and Hoburg. The sandstone with thin seams of shale or clay, as de-
scribed by Hisrncrr. The fossils are scarce, mostly of the same species as in the
oolite above. The few Gastropoda found are well preserved with their shell.

Rone. Sandstone and shale along the shore.

Ostergarn. Shale beds, on compact limestone, with Chonetes striatella and Atrypa
didyma.

Slite. The lowest shale beds along the shore.

Hallshuk. The lowest beds there and for a while to the south along the west
shores of Kapellshamn.

Stratum b.

Wisby. The limestone with interstratified shale in the neighbourhood of the town,
well developed at Snackgardet, Skalsé, Wibble qvarn, Héeklint and some localities
along the coast northwards to Likkershamn, where also many fossils have been found.

Westergarn. On the fields farther inland, above the shale, scattered fragments
of this stratum can be found.

Lansa on Faré. Limestone and shale beds along the shore.

Slite. The median beds in the sections near the coast.

Boge. South of Slite in ditches along the road and in the cliffs near Klinte.

Ruthe. A canal leading from Stor myr is cut through strata of this group.

KONGL. SV. VE. AKADEMIENS HANDL. BAND. 19. N:o 6. Na

Gothemhammar. Beds of fine grained, nearly oolitic limestone with an abundance
of shells of Lamellibranchiates, the same as found in the oolite of Bursvik. Fine spe-
cimens of the large Murchisoniw have also been found here.

Dalhem. Along the brook near Nya Slitegirds a good section is laid open, rich
especially in Brachiopods.

Kriklingbo. Marly limestone near the shore with the same fossils as at

Ostergarn, where the limestone ) is nodular, compact and gray.

Stora and Lilla Carlsé, where the strata are filled with corals in regular bands,
each species apart from the others.

Lau. A declivity east of the church consists of beds of marl and limestone and
is very rich in finely preserved fossils.

Grétlingbo, Nds and Bursvik. Beds of oolite and pisolite of variable thickness.
Fossils much eroded and worn, the Lamellibranchiates extremely abundant and well
preserved.

Hoburg. Above the sandstone oolite is resting, at first sandy, and afterwards more
compact and not so rich in grains of oolite as further north. Limestone beds follow
above this with seams of shale, containing Crotalocrinus, Labechia, Pentamerus galeatus,
Orthis rustica, Strophomena euglypha, St. filosa, Orthis hybrida, Rhynch. deflexa, Me-
ristella tumida. Two peculiar forms of Gastropoda have been found here.

Stratum ec.

Lutterhorn on Fdré. Low cliffs of crystalline, grayish limestone with Oriosto-
mata and Tryblidia.

Wialmsudd on the northwestern shore of Farésund, hard crystalline limestone
replete with Cephalopoda, Gastropoda and Trimerellw. Near to it, farther inland, is
a place Sandvik with the same fossils.

Slite. The uppermost limestone beds are rich in fine shells, especially in seams
or vertical fissures filled with marl. Partly a breccia of small, comminuted shells.

Samsugn. In the extensive quarries of the limestone a great number of Cepha-
lopoda, Gastropoda and Lamellibranchiata are found.

Hall. A canal near the farm of Westés has been cut through bluish, nodular
limestone, rich in finely preserved fossils, especially Oriostomata.

Halls huk, Bara, Ardre and Ostergarn, Klinte, Wisby, the top of Carlsé, are all
localities nearly resembling each other lithologically, though their fossil contents differ.

Follingbo, Storwede. The limestone which is extensively quarried, varies very much
within short distances, being in some places coarsely crystalline with many remains
of crinoids, in others again of the finest texture resembling lithographic stone. The
last mentioned variety consists mostly of fragments of Cephalopoda, with some few
Gastropoda interspersed.

Wisby (Kyrkberget, Kalensqvarn). A gray, soft limestone, especially rich and

replete with remains of Gastropoda.

12. G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Martebo a peculiar, yellowish soft limestone near Myre, rich in Oriostomata and
their opercula.

Fardhem and Linde. Some isolated hills as Sandarfve and Linde kullar, partially
consisting of crystalline, crinoidal limestone, partially a conglomerate of larger or
smaller pieces of corals and Stromatopora and partly fine, earthy, red and gray lime-
stone beds. The last are remarkably rich in shells of Cephalopoda and Gastropoda.

State of preservation.

The state of preservation of the Gastropoda as well as that of other fossils in
these different rocks, is of course quite as variable as the nature of the rocks them-
selves and seems at first in several places quite unaccountable. So, for instance, the
shells of the Gastropoda and Lamellibranchiata are in many shale beds, as a rule, dis-
solved and present only as nuclei, while corals, trilobites and brachiopoda are well
preserved. Thus in one locality the shells are only represented as nuclei, as for in-
stance at Petesvik in Habblingbo, and again in a neighbouring locality, Djupvik in
Eksta, they are well preserved, with their shells. It may also be that many genera of
Gastropoda, as in the shale of Wisby, only occur as casts or nuclei, such as Subulites,
Loxonema, Murchisonia, Euomphalus, Bellerophon and Tremanotus, whilst in the same
bed others as Oriostoma, Pleurotomaria and Platyceras have retained their shell. In all
probability there is something in the condition of the chemical or mineralogical nature
of the shell which thus causes it to be dissolved in one group and preserved in the
other. In the upper limestone beds again by far the greatest number of the species
are provided with their shell and all the delicate ornaments of its surface are visible.

But the difficulty is to get them out entire and perfectly intact from the rock.
In such rich localities as Samsugn, Kyrkberget in Wisby many specimens can be col-
lected as they have been detached through the disintegration of the rock, which is
often crumbling to pieces on the surface. From the limestone of Sandarfve hill they
can be removed by carefully using the hammer and chisel. By delicate operations
with sharp needles they have been prepared out from almost all sorts of limestone
and been cleaned in greater perfection than could be expected at first sight.
In washing the fine, marly limestone mud, which is often found in fissures and
has probably originated through the decomposition of the limestone, many small Gastro-
poda, such as the Murchisonizw figured on plate XV have been obtained along with a
number of other interesting fossils.

The few Gastropoda which have been found in the sandstone are remarkably
well preserved, showing the fine sculpture of their surface.

In the majority of specimens the shell is entirely converted into calcareous spar,
but in a few others there are remains of the microscopic structure left. So for in-
stance in the genus Platyceras, in the common Platyceras cornutum, where at least
three different stata can be discerned. The Patellid Tryblidium has also the intimate
structure, to a certain extent, well preserved and also, on the inner side, the peculiar
horseshoe-shaped ring of muscular scars beautifully and most distinctly visible. In

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 1[9. N:0 6. 13

this genus, as well as in Cyrtolites, Bellerophon and Oriostoma some specimens still
show the pattern of the original colour bands. Traces of the nacreous lustre are also
present on the inside of several species of the genera Oriostoma and Pleurotomaria.
A number of specimens of the genus Oriostoma has been found with their large,
calcareous operculum in situ, thus permitting to distinguish several, nearly allied
species, the shells of which show very little difference. With regard to the position of
the shells in the strata it may only be remarked that such elongated shells, as Mur-
chisonia, Loxonema and Subulites lhe horizontally or parallel with the plan of strati-
fication. As for the rest they are heaped together without any order as the shells at
the present day cast ashore.

The Murchisoniz found in the shale beds of Wisby, and also many Bellerophons,
had been almost entirely overgrown by colonies of the bryozoan Ceramopora and others,
many times larger than the shells themselves and thus evidently preventing all possi-
bility for the animal to move and consequently killing it. In a small lake south of
Stockholm, Hammarbysjé, I found in the spring 1882 the common freshwater bryozoan
Alcyonella fungosa Patias in great abundance and nearly every colony of it had
chosen a specimen of Paludina vivipara L. for its basis and so completely covered
it that the animal was unable to move, and large numbers of them were dead, the
bryozoans continuing to thrive. Thus a powerful growth of a compound species has
acted and still acts as a check to the increase of another species belonging to a diffe-
rent group and has probably also been an agent in its extinction on localities common
to them both.

Distribution of the Species.

There is no doubt that the Gastropoda I am about to describe, numerous though
they be, are only a fragment of all that once made up the fauna of these animals in
the Silurian seas of Gotland. Several strata litterally teem with their broken shells
and it is evident by several of these remains that they belonged to many other spe-
cies than those mentioned further on, but too imperfect for description. As far as
known at present the number of species and varieties amounts to 174 here described
and figured. The numeric strength of their group in relation to that of other orders
from the strata of Gotland may be seen from the following survey of the whole Lethwza.

List showing the number of species at present known from the
Silurian Strata of Gotland.

Crustacea tPrilobites seis: see!) 45025) oct set oa 53
Merosvomath potest 822428 <2 -_ atl dee. 2
Rhvllopod ays ee e8 oes ee 4
(Oe Reta s FS Ee ee 30
ITEM Dd teens en nn 1 90

Annelida according to the researches of Dr J. G.
HinpeE with addition of the Tubicolar An-
TIENIC ES eee ee eee Beer SELEY are 50

Carried forward 140

14. G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Brought forward 140.

Mollusea

Cephalopoda about -_--.------.-.------ 100

Pteropoda pe: neseee anne arene 5

Gastropoday St See 174

Lamellibranchiata about ----------.--- 80 359
Molluscoida

Bryozoa fabouts Sess ih a 50

Brachiopod apt tes a= s2o site b eee ee 150 200
Echinodermata

NGteroiden 222k: \: Bye eeeeeee ses seen 2

HM chinoideacs: 2-242 oe og 1

@imoigle a: tes 2 sn 3 nat ge Jee 180 183
Anitiio zo ama bolt 42-3 - Be ete ee 100
(Gipni sol pee Be 222 eeee 2 soe cenmee seaas seen sos eeseesee 5
Spongie 10
Dubious organisms (Algz probably) and others -_-_-- 5
Pentaculite ‘avout 22/2). SE eee 5

Total itt 007 species and varietiog!

It is to be observed that the number of species in some groups has been rated
somewhat low and that in all probability a detailed research will considerably increase
it. As it now stands we see that the Gastropoda vie in numerical strength with such
large groups as the Crinoidea and surpass all the others.

The minor details in the distribution, geographical and geological, of the Ptero-
poda and the Gastropoda may be learnt from the annexed lists"), in which first the
chief localities or local regions are given in 27 columns, and then in the six last columns
a summing up of their stratigraphical distribution. Under the headings of the loca-
lities, a signifies the lowest stratum, shale or sandstone, 6 the intermediate limestone
or the oolite, ¢ the uppermost limestone. When a species is recorded as found only in
a and ¢ this has been considered equivalent to its having been found in 6 also or in
all strata.

As to the names of the localities, it should be borne in mind, that some of
them are intended for a small district around a central point. Thus Hall chiefly
means the strata ¢ in the canal near Wests, but also the strata near the shore and
at Halls huk. Wialmsudd includes the adjacent shores of Farésund, as the strata of
Sandvik, Gothem and Bara embrace chiefly the shore deposits at Gothemshammar and
a number of quarries opened westwards in the direction of Bara, where a little hill,
Lara backe, contains the same fossils. Linde and Fardhem comprises not only the lime-
stone hills there, but also the marly and gritty shales.

The limestone beds of Samsugn in Othem, those of Wialmsudd and Wisby as
well as others are very rich in shells of Gastropoda intermingled with those of Cepha-
lopoda. But all these localities are by far surpassed by the limestone of Sandarfve
kulle. This is one of the small hills, which in the central part of Gotland, a little

}) See page 16 and the following.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 15

south east of Klinte have been formed through denudation and all prove, through the
presence of such fossils as Pentamerus conchidium etc., that they are of the same age
with each other and also coéval with Klinteberg. Sandarfve kulle, which is one of
the smallest, attains a height of about 170 feet above the level of the sea. About
80 feet of its substratum consist of shale, similar to that of Petesvik in Habblingbo,
The superimposed limestone, which forms the chief part of the hill, is in the lowest
beds regularly stratified with a gray crystalline limestone, which passes upwards into a
concretionar irregularly bedded limestone. This is partly bluish green, soft and earthy
and partly in large patches red, giving the enclosed fossils with their colour a certain
resemblance to the Lower Silurian fossils of the Orthoceratite limestone in the main
land of Sweden. This rock contains in great abundance beautifully preserved shells
of Gastropoda of numerous species and also rare Cephalopoda, such as Ascoceras, Ophi-
dioceras, Cyrtoceras, numerous Orthoceratites, and also shells of the Lamellibranchiates,
all not found elsewhere. The fauna has a peculiar dwarfed character, being composed chiefly
of small shells, none attaining to what may be called the average size of those of the
other localities. It forms, as it were, a narrowly circumscribed, local fauna, which has
hitherto yielded no less than 39 species of Gastropoda, only from the the red and
gray limestones. Of these as many as 27, or 69 percent of the whole amount, are
peculiar to this stratum. This surpasses by far the conditions in all other localities.
According to the list, »Wisby» is richer than any other with 77 species. But it must
be remembered, first, that this denomination embraces a much larger space than the
former region and includes such localities as Kyrkberget and Kalens qvarn, where the
limestone is in fact a dumachello. Besides, there are many other localities for a consi-
derable distance along the coast where the same paleontological characters prevail.
Fourty one species are annotated as pertaining to the stratum c of Wisby, but of these
only the small number of ten is peculiar. The shale beds at Djupvik in Eksta con-
tain a Gastropodan fauna of 25 species and of these nine are peculiar. Of the other
richer localities Samsugn has a total of 34 species against six peculiar, Slite 25
species in all against four peculiar, Follingbo 2U species in all against six peculiar,
Klinte 23 species in all against two peculiar and Ostergarn 21 species with only one
species peculiar from the stratum 0b.

What must strike the attention after the first glance on the list of distribution
is the great preponderance in number of species of the North Gotland localities over
the localities south of Fardhem, such as Rone, Groétlingbo, Bursvik, Nas and Hoburg.
This may chiefly be due to real poverty as no such rich deposits as those of North
Gotland ever have been discovered there, but it is evident that the total amount of spe-
cies found, especially at Hoburg, will be increased in future through continued and
oftener repeated researches. Characteristic of these southern parts are the following
six species, having their northern limit at Grétlingbo. They are: Platyceras disciforme,
Cyrtolites obliquus, Pleurotomaria dolium, Murchisonia moniliformis, Eunema muricatum
and Craspedostoma spinulosum. As a contrast to this minority, no less than 95 species,
or more than half the number, have their limits within North Gotland as far as Wester-
garn in south on the west coast and Gothem on the east coast. A few continue as

16 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND. °

Synoptical List of the distribution of the Silurian

ze Dn Q
Paro. 2 o | = 2 =
= => = e § 2 5 = = a z.
Falke Palade s
2 E E
|
Pteropoda.
Conularia Sow.
6 ON eh oe ay ee (Nes Se See ees a
agoaver|! te ss~ fiewes2eu| toe See [ce ooee | Cee | Pee b ease ||| -seeseil| eee
Sere 6b RES Pe) OR Se nee (SES | er ek ~aheae
ae b PEPE SUSE eee EE ee ee mere hs oe |
db. cident. || Moe teed ak fe EAD) oe ae WEN Rate |) S252 2 || 2 aseee
3 1 4 1 1
Gastropoda.
Fam. I. Chitonide Guitpinc.
Chelodes Davipson & Kine.
i Bergmani DAV; So 4KING —..-22-.0cees cas ne ae ecne ee pecdeeteacs |lcsoe-< imeeecedl ceed. || eeece al pe cee [eee | eae eee | eee || |
PMGOtLANGiCHes..*e serene ee ee a ne ee Se ee Ce eel ere lt 2 2 aineceee ey el eee |e Cn, | eeeee lee sce | ares
Fam. II. Patellidw p’Ors.
Tryblidium Lym.
SeTeticnlatimy DMs: Sees UNAS eee SELL PEAR oy c c c CON ee ee ct || Peo | eee er reece | eel eee
Abst o ulis\ pat det at Oo ih eens el feel Ohio hee IEE O c c ey || seed Nak. eee c be ty | Eee (tS
BG ofadintnimyn ste 8s 8 5 re ee Ge piel ins ontiges Geers || eels eee ern ere Me pere leerer ye | Se
Fam. Ill. Teeturide Apams.
Paleacmea Haun.
Oiaolaninm ny 233- <0. ea ee Se ek A a | || ence eee
Fam. IV. Calyptreide Bron.
Platyceras Conrap.
AigCOLU REMMI Ge he Sok en, ete Seen en Onna ab c be | abe c abe c abc | abe | abe c be a
S$ war: loricatwm’ ins <2. 22. e. sce wow oe Sec oe we ee ts | Re |e Netcare eee | eee | ee Ul Kecsece
SMS PIAcONT SOW. Pes Ponts cee ttre tee cae nee a re ee ee | ere SRM ERO et | eee een | re @ ‘ltesse20|':--.-4) eee
MOrdisetforme nye. eke ee ae ae Id ee NESBITT TSS FR | | en | Orme eee | en
AliMenoxnre: mi) shh 3 eae. ae ders ae ee A goal aie Ae Slee oll eee || dapat SR | a fot ase lL Sel ame | Ree seta | ae
12 .cyathinum ne 3 ~ pce een a beeh ie ka ek ie [fee pees Ae sein le ke ely 0 a (Ae A Fees ieee
Fam. V. Bellerophontide . Coy.
Bellerophon. Monrrort.
ST Siaip Hae a thc iene sot ea ae cee hg Sa oe con'| eae Sass 25 a eee c Pe Pes = 24 Nese [eee nes
TAY fancidbus sis 22.2 = 2 Sac. sceeesonceee sede nc caer een os aSe ES a, oo ee cee ees ah) | cee | Pee al | | rene | | Boyes == ||| co_sss1|caseee
a a Sy -4 od) Ks iv en Dc mn tat em SGN (aE oi) (PRE | ATE | aoc | De pra MB || eh |) mee. || e5ceselosaees || seccee
MGM Leeman eee nce fe cen Ree en ee wee 2 ee Or ee, eee yeaa | eet | Pe gee | ees eee, | ee | ee | et el In SH eeseee || asec
poLvedautipiatus nistatee set. MAG? 15 is PACS ERE PARE tit: SRN HERD || Ree =o TNE Lh: SAH NER | ARERR | (Pear 2 2 eee
Wal Situbuilosnaint-o... 22. Lies eeeiat Ae ete SES BE Te vONaN lees eee _ il ERS CS. ee) ga a | ee ee
Carried forward] 3 | 3 |-3 | 3 | 2 | 1 | 3:18 Jo? | B.] 2] 1

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19, N:0 6. |
teropoda and Gastropoda of Gotland.
| = BS E | Stratigraphical distribution.
| & || c: SPS pe ie if |e Neg
z 2 3. rat c 2 ~ é Tp i = = z I ol Only found Common
2 = | ne = S 2 EP Qua eae = = E = in t
Siem it sen ihe Pe bo Y Be fs |e = | a .
eve || 3 Bee dee te P) ? ale <5 et cold ep
| = a | a Din) rc Wateaita ab ner
a EE EC a Le |
Rees Nee PRaSe SPSS be omc-6 e----- | ------ a we---- | ------ Sics2s4)) Se B5528|) Ree ceey Picco | Sessa Werner Meeeeral plement) se |) oe * ea
cohder lH eacese. || teal! eedill eeuecenl ees 25 =e ess" |e el Ra [POS ae Aa | FER een eee a ( e * eee ‘ 7,
cass. | efaes: 4! SSE] = eee eee NE Soa RES ane Mie ee b sem eens | =a mmedll| Pome | once || emaennti|) oeocce\|) cose oe *
ceeese | seksecl) zsatecl| setees || cae') pees ee Rd PR een Se! Se, | eee ened eee oe een Meee * |) 2 | eee eee eee
cockre. || cefaes | cceeeni| acco] eSt=c8l]) Seb call) eee eR SE ees eer ln Cr] Wn eee Dee | el Pee eed! ae eee eee (eer ee |e oe *
1 1 2 1 2
SSF WERE AEs eae ce =----- qSet05 2S 6e5 Sete nt ----- oer =esS= soeese é226=5 Beate ------ me te pee Sens *
epee eee enced |reecea| sencs—= || areca) cceeos'l) at mmnilleeeara [Panneen.|} a--<= OY | Sezen Go| Cae a | pecsese|(tec-eai|) eee || Ramee ead eee
emcee, |b tected let ee ee Ne en) | Kaba bs Ro eit | DORaMe at! [eae peat ek oa el tees & areas * oe aoe eee eee
conste:|| ceedet ||) cecal] Saccsedl| eceeemoll leet sss epee em eel [ieee emer ial | tera || meee UE eaeeseh (uae aces ab ae eee Reed bereseseg eee d| em *
coeene || ceesee ll ceeded || GU EES See Eh ES a OR Sean | ee ee | es ery cence. fees | een eee, * Saeeee | |)ossoce| eecee=
REN og ce eee reset eee) Se eee (ene ee c peer Reet | eeaeeee (emery) | eererreet| (ecereeiee lemme ee feemeres| (ge 0 eee Nene teem
a 6 abe abe c abe a abe abe b a b b ab Cite ny ee | Jai Bn eee ge
Pee ||| ore me] ee (A eee fl ee eet ee = ea eee | ee | ce eee eee [ere || ie Saeed I eee el on S| gener 8 ee *
2 eee lees PER ee ac aieeeee | Ge c eee eM ere ese Ista If exer eee | eee) ce ence [heceecest [fm ia [omen meme
“oSose |) ccscn|| <oiers)| ls ee ol epee feel a ed esa Sse ka Re (a7 Se (ge Ue Ai el eee (Ate | ceed Se EEE A
oedece b esdees € Fee eal We eee a = Bae b Feeds corse b ab SoG |e pee Al lat ees * eee oo |
et ee aa ene ea eee ee ee | oe eee | eee ieee dene | a cused Sew ene | cccces | --eetee |) aersee |) Seacen. ||) Seecce # | ne fetes | cee |
4
wostee | aeeete || Maseacae Sec 3)l|| secs Gr URREE Se wR eS) Ee | Se ee a SE eed || ae = |i ceanee soises || Sasse5 * sere-- | ------
zene || seckcue |], Sede See, sll! ecceces|| Ze | ME fe Pal Pe ce eer || (Ue || cg | meee eee een ee (oR *
cape | eseeee | Seen es, = S| ee a = el a Bees | ee. Nee et ON Ia c I eres * |) Sa ee Ce
Bec 2 b b c — c 4 c oe ears Ree (ee [ae Rie oe oe i | ir pee eee oe *
eo} |cnenet || oeceae |e sok | <.cc. | eee Ze" SiR RN) jeeeee STG | ese eames) | ene a een ee a aennee omen! econ) | (eee tees
eee eee ch ee | Te, el eee ee
Meee cele amp omera base 2 hus.|. ola | 2 | 3 | ...... hoe ae 5

K. Vet. Akad. Handl.

Band 19. N:o 6.

18 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND. |

Faré eis | z z |

—| = | Zilededndid apleiahea Hee heeahasel

= an =e AF Se A= be dS PSS

= = = = = e e ne sa 3 ee |

aaa Bo) oie | | = Sle | Sa

° = 2 4 =a | | = ]

Ae E z |

Brought forward | 3 8 3 2 1 3 | 3 7 3 2 1 |

Bellerophon. |

PUG Wenn R Satan eee ese re eae Sec eee eomne eee eeeeeann = Co || ====== Co) weeeee | weeeee | = geet teeee i (yes | jee |) ae = 2
O()Bipeni nt mi bet a cesar eee eee rae eee |e eee | eer © | wneeee | weeeee | oencee | wee eee | eeeeee | -eee-- | +--+ | eee
Olielemanwnlus ns cones tose = ne aas eee ae see eee eae seceecceneonecen | ences |/eeeeee | etenee || enesce | o==F22 || esece= iseace | ==saa- (Be easeee | eeace || oa ane
OM Matevittatne ns -<c8- secs o eee aee eee eee eee nee oe epee eae w aeeen nena bemeee on hasan ironman) ie oaoe deer feeteee|| eee |lieeats || oes (0 Viecere | Soca) || econ
PAB ofeyial 0 1 ae ah gee eco Soe sea Se eee oe coer nee wee | secre | neces | ceetee | seeeee | ceeeeo | 222s | oe wee | -e-ee Pe | See S| ene ||
2), FS 51 NE ae Rie EEN ne ee ee eee ee eee | eae | Chieceall cocoa eb ea ee tases eee ope || seco |) cacooe || cocaae lcacoe st | coecce

OF PriLOH AGUS: 490 We sae ee a enn SNES pee Ree ee Serene pcan) (Rerwennl (leone ocean ermal Re eee (eee | ena Wl leerenge eect ent '

Cyrtolites Conran. |
OG lamellifer dn, seers Pee Nes een arcs pestc os 4 oan nee ene peroneal |ieon cae thao ra iece alba Bo | 2----- | -2---- | =-2--- (Pe Wessee |) Se=ccs |\eeeoe:
Nay) ESE 1 ce See oS oe PER RE ee eee coe eee ae eerie! Verena || ese) coe Wears pcos | eases fososes ccece= |fcssza | cece: | cena:
| 28 arrosus 0 we | eeneee | -eeee= | seeee | ------ | ----- | ------ | =e == CF |) eccoed | ease eeeeee lean
| SAS) OVERLAYS, 975 eee ene 5 AS SE Se he ee BS SE ae eee zeae || Soe | Saee eS ece nae | ceca |} Smee |) ab ons bene waents | seacam |/---2--)| so-=c= | W22---
|) SO fenmyomphalussnesse.c.c-ccee-e steer ee ce cease nese nna an ene eae eee mene al [ene femme Vereen ome cece cee eer a eae
Sfdisens We _cotacc escent pS Rs | ecm | eee (eed oem cee alle eae. Us Olean ceed eee
Ise eo rbiculugp ms cets tere emer rene ec aseeeeeee Oe a) ean) sea css I Sees | Ses) eee | See -do || sesso. || cesses) cancSe. |) sete | soon
Tremanotus Hauu.
SSB Nene ER ES 105 Sees rece ae aeeeeee ce acesee Soe onceP ae atmos Beoacozaceasemrns Ge Seeacs ac Cie ae as | ee c c CANS Wt lemme | (ere et eaaaee
34. Compressus! Me: .-)-c---2--b- scceeeseecenece deco seeeecheneneeaseecncenesedenceem | e=8eee [lem ers || ereeee [lecemn=|limaooo | on -eamlli--e oleae ee eee ae ea
Fam. VI. Pleurotomaridw v'Ors. ). p.
Plewrotomaria De France. |

BY sya ter aid Ep gee ee nee a Se BO Cee Re Sree pee Seer eel locemers||.cee-c~ |f sano eseeeeilese se Cm pees 5 |lesmees @ Ov Fl Sebee he Aare
BGkeradata 0: p< eee sean ees wee bce caeee ee sansa eco m cscs esanes | poore aca emeeedlleaance Wee eese Pee eeeseel tee we | Seal S ese s)|| Stace ier eact | acim:
eS aniainn arsso miuanse se Sr Beco eet es ee eg wee Ble cee eee Boece | emnene }b a eet | er Jigen .55!|Peereats |ebeeet lllexsene wl eebee
BS av om bani fe ece ee eee wesc eee oe See eae esac eee eee ee ee | feomecel [eee (ese | seats | =n coup eet = beet | es [pete eee le

OG iclanatrata ness < eee eee e Cees eae eae ene eS care ace ete ee ee Hees Bacall enone 6 c- ||Peekeilies 2 be ca {epee eco }
| 40 plandiformis mn. --.....-c.c...---c0--ccececeseeceendeceence-ccaeeeesecccceecds | seesee |) eee=e0)| Boose || sceeee | enc omeip <eeeea | eemee fic cael | Pemerey flee [nono ona
Adhiformistns <select ecm eee heme eee wece-~ | eaceee (GN reed cena eee
WD ulntetascra tater. c0 sete ec tA oe cee eee See | (ern eres | ey | ee ere ee ee eo Bele Sep), occzeag eee
QS, Fiindetons see Pee ae a tok on ee ee ote ae Se ce eee eel lore coe ten == = [eee [eee lee Pa Nos al (eee | ee Set eee, | ene | ae
AA Olinion: <2 ooset 2 cee oe ee a ee ee Be ee ell eee beeen e= fem emeen fhe eee | Renee | eee en ees By seca tesene= ll eeeees

CEB AVS] On {STS ie ise ees oe eee Seek Peace tenet ne pe coosse coeeceney| leseees|| Hoaeee || ==aRo || eosccs || costs (le \lesasce | eee p © | eee ipsseeetll scosk:
ALG WAT Toy. cl iit cows espe ee oe am me ee aera fe b (Tn eeseee eee eees esse | cece =e: |iecrere ac? || al eeeen. Il! -2 eee

7: rs ENGL Thr Tae eee nae ge ee Ri eee ge mr ne Pe | eet || Spee ceca eearen | [coeeol|| ceo-es)|| soteea ||Rasee |[/cteass |) 222272 |) coe = Weeeeee '

ASSIA sige rug yee ee Se ee SRP Be eee eer lems fee eaca Pee eed bo ss Pits UW loc sce |) ence eee
Auth ul osnp nes ets heehee oes Meee ae ot eS FS ove, han a ll vege [pageecs | Reena ce beseet eee es [Pe <a ee eee ee | senses
Or rob untaen: cee peweess Setols | ae a ee Sea ee Ess. Saat 2 eee ae Vee [i ceeselh, sand Re Mh 2, Leal tom & Oh GE Rae eee [Pee ee
iWeb lle vercal ceyisei mae mb=ete nee Seba e neon an gear ce cto kenee saa oeere_e neeeen denen | Resco | eee ween | ore I Se ce he | 2a | ee eee ot Nee ok
HO Welli peice wELis Mee. Ses eete he i eee eee eee eee eee) eee | --s+ eet .n2 PE Sig pra Re oer I ese | hema) | baton
VAS Bhi cinta eUaiiiee tc -- aceeeeee enc en Aer re ee ee eee Belk Se le Sele oss |e | abe} cc b c ikel eats

Comic torwird | B | @ | oe) 62] a) a Rememes [ee |e arpa

19

s0%6%

N

BAND. 19.

AKADEMIENS HANDL.

VET.

SV.

KONGL.

Ey |r) fe ar ae ae eat eke eae a ie edie hn bas Geen ths She Gi Ste nati ieee cht a aE ee
i ie ate at ea ee ne H ' : roast oe te at at ee
Palak —|— — = = = =
S12 2 oS ee tS oak ma at. mt ' eH ie ate fg, Sie Ree NS Tie ee are ae ee ae gt ae A ee a
Sica i = ae: Seca ge ae a oe 0 fee ete ott We cis ie Giese giet Gt eke Bx)
z | 3 1 ; ra oe gue ih :
- e ' ' . ‘ ‘ . ' ‘ . ‘ ' . . . ' ' ' ’ . . ' ' ' ‘ ’ . . ‘ ' '
+ ae ‘ ‘ ‘ t ‘ : ‘ ‘ ‘ H H ‘ ‘ ‘ ‘ : Hi ‘ : ‘ : H ‘ ‘ ' ‘ ‘ ‘ ‘ H
2 Se] «0 bn Av rea Se eee ed OR Sea © i a ete ec el ee a Ce ha eer = rn ie
co Cet + ' ' ‘ ‘ ‘ 1 ‘ ‘ 1 ' ' ' ' 1 ‘ 1 ' 1 ' ‘ 1 1 + 4 ‘ ' 1 ' 1 H
Gea ’ ' ' ’ ' ’ ' ' ' ’ ' . ' ' ' ' ' ' ' ' . ' ' ' ' ' ' ' '
=—| | z =
o , . ' ' ' ' ’ ’ ‘ . ‘ ‘ ' ' ' ’ ‘
a 2 12 See chasWe CRS ee a aetiee t H i ou ee # mies NGOs ie ey ae ee ES
| jeelhe heat y in: H te as det ASR
to | § - --= ;
eB 5 Hiaei{ att th an) Sa ine aioe ee i ene sen A ee i pentane Sh i i ee
Fahd lips ores 2 Oo roi ta thet Si pa ath eth et 2 a ae eye RP eae ie SeueAR Ee eile Clin ation ag od) een Mics
S |b ep ot act aad ! Le ste } : Hh ea erate H 4 Gata a poder
2 =| pers ss 2 Be A-E
° ' : : ' : : ; iad Neon tas iets oh
s om ; ct ae Be Bh te cee Ne ae Hie De Titan taegthne § * H iu Sta) elie le git ae aeg wane” (Cuere
eat i 1 a te GHP tigen am } H rae rie, (tee a ete ames ot BB 83
Hoburg. & aN i ud eet eet te ok isthe WE et iN tie lige tt Meee tama
; Het Bet Fs te Bie 20h ate : Sh 4 1 Stent phar! amet acd! elt Heat ae
Bursvik. 32) UE ote sgt ' Cees SiS e st oP at Hemet H ; 1 oii aerate at sie SH
S emt fae : ae er ea an ried aa : : aia ae Snes Jie:
Niis. R Paes He ! Netra ote Bet eat He th Ae opt ates AST AIT tt pe athe atime ao em am
Grétlingbo. 38 H 5 ame eet Hed Y : ' i ne rt ' ' S ioe oats
Habblingbo. =| & eet bis Ppaeiey tae 5 ie et Bt eA aC att i} 1
ten Cai eee ‘ 4 a = ie a ‘ Ee ie ret Te ae iy Pith ae
Lau. R epee este He pa eee eae mS) Hl a i ee se to eng a a ae Sau
Linde, Pardhem. | = Hoe ten Retina ete titel iN oat : Suck Hee Grote oes od Herter Sear mee aig tHe fee ||
Stora Carlsé. R I ial ae ace oe alt ee Hmshier ot es (en p 1 edt es et Dee ame ea I matt sce et ml neh Tt aa te x
' ' ’ ‘ Fa ' ' ' ' ' ' ' ' ' ‘ ' ' ’ ' ’ ' ‘ ' . a
ge a Hie tlice oe iar iti cobe |) tan, brat eis (eed th dhe ORR a Rene eee ile nr
Djupvik in Eksta. mn a a ' ' peed : sy Hy itr em Pree ts ne oe eon oe ; ; i eeiert
Lilla Carlsé. rt eit ah an ye tag eat gst owipau) atio«tt ae ieee Higa SI mes chet lh eH
fF See Ee a ae Set entero are i bay ; aaa peer be
Ardre. n BS Si rue a an tamtte lime te Bite : ek tie igo eo ee chee eka Silee:
a a i eoioitiewnt mntienti—a q fest ey stor aie ati ol se
Klinte, 12 Eis A a i mB ree te that o } aE ye Sect oe ert treet HS OH it Sa at Ra IDs,
Bete GN a gt ase Wie OMe at e rhe a ; SE monte ies te eg ie tpt See
4 ae ae pene ae Ha De eerie yee tea : Hs a Say ae me cam PL it 1 it 2
Ostergarn. nr Tee Sele eign le ath mes sepiittamertns malt th Rata ct hes Po i Mie sie ee ig ale ee city fe ES! st sae
Kraklingbo, 2 So a ah eg tected th with mai melt 2 cars Pe Gia We Renee re ter OS ee Sea hae ic
’ ‘ ' ' ’ ' ’ 7 ' ‘ ' ‘ ' ‘ ' ' ' ‘ ’ ' ' ' ' 7 ’ ' ' 7 ' ’ '
Hy cies SUE GU te Ne Se a Suen % ver ie Tie ope oar Ratti the bs ried eeatice ae oe
Westergarn, Act Le er a er Hale hy ete lieth gamete ad He ad Heme elmer eed Seem Gaeta Shs SOR ee nae op et itor}

20 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

62 alata WAHLENBERG

_ Brought forward

Pleurotomaria.

54 qualteriata ScHLOTH...........- hoes DORE ARE remee te cern aee
iS ue Ua Che Rete Re ee re ee Re ae 8 5 eg ann oem Se
Dom Ophemeneis ins ce eos- Se oe ee eee mena n tosee ee aee
TMC OTA ALA I ee ee eR oe Pee ae eee ee a

58 eequilatera WAHLENBERG
H9Mlabrosa Hawi "Aiea es eee eee et pies Lees
GOL ata nese ee a ce SER ee ee at. Be cree sc ecee eee
iL pica fen rae ee oe ce me arene

63 var. subcarinata n.

Galan opposite: Wyeecn esse: eee ce nc ewan see See ern eae
(AD) ROO Os eee hescicc sch seseeo.c oe ee Se comes ae SS eee senae Jseereeg sey oe
(a) UY MD: hy, seqseapeeeeeee ao sacar eso eh et ee Saseenees geet amet epee eenecos
Giitrenatatne ee ee nasa pecan neo SA ne fee Soe ee acces
(6h), (eTG TT ES im rege ees See nee oe ae pee ER ey ieee See Ree
69 Marklini n. --

OWcirrhosa-tnes sss es ck seen eee, See ceeb eee ee cheeses Soe Ree

U2) UERORIDES 2 Gp 8 aie eens coe anette onckeemere cee ee ee cee ees eae one
Voihelictna: meets: 2 S80 ae hes Ree ot aia PIS ries Fase coca

CCI CYL UC) nee Sapa ea rete RR a Tem See ape Ae

Murchisonia p'Arcu. & VERN.

cs

eingulata His __.

MONMILONMIS Wee t= e. secenace aces ssaccn ere sence Bees eeestee ena Seceeeenes

ID 1

COPSLETESL WET Fgh 1 2 Ne ee esrcer ee ns Seen eR oc Femme meee

a 4 at st

ao

BUD PCA VAN Mee sae eco eee ene ee nee een neers

79 compressa n. ___...
SO attenuata HIsss.-.0 cece eee eee ek eee ek Renee Sear e ene
top LL tk) ners Cee me a soe eRe tare Reto is Sse a Oe
SZiomimndaems sche gee eee See eee Saeco wens Re ee
ESS TL 1 ff Rae ee ts See See ak Sy ee Oe an Ree eae

Sd imbmcata uc cee see eee

Site ameell a tea ace ee ne eae ae a ae ee ee ee
Sb tcachiledtay nies eee eee ee aon es Be Reet See
Sie dehexa ns 2st eee. ee ea ee eB ae oer Boe ee ce ee

Fam. VII. Euomphalide n.

Ewomphalus Sow.
SBrigatlandi cusiyie ct sacsy Sse ke ree ree ee

SOhiriqnetroy ina be F heya se et 6 Le ae

Carried forward

TH

wm
S
ral =|
2| el 2
= = ag
_— ic} =
= oe me
2 Sr i, =
2/2/92
= = >
s cg
5
6 4 6
Pere eee c
CiP ahsceese e
c Ocemlnese=
La a c

“OHIS

*oqaqivyy

“AQSI AL

‘oqsull[OT

RIvG pur wayjoy

oo

*PABASLUD

Fard

=

a |] x

eae

i= wm

on =

a)

5 5

(nl? |lessos
seh b

( eesoeco

c c
ey, b

8 9

21

19.

BAND.

AKADEMIENS HANDL.

VET.

SV.

KONGL.

sa| atte cde ee oe eat pot hen ei <n 4 tees : a
.| 8 > -—
a : ‘ Ser be His. Fi ee a ia
od Bees | Me: | ico + i oe ig ipites tne feat: ho odie o
ea ra ; ee Si
2 ey -|— —— = — _ —
iB 2 i i ; ais ee f te ata ; f ;
3 GE] o jaa een A te eiott AC la eR ie ae ee
2 ‘ ‘ ‘ ' ' ‘ ‘
| ea aka aS a
3 ey an aie : om
a= ° 2 Het Sea eee ks) Gat aa ' * Nese * * * * * % * 15
& | tae i a
H a — — —
Be) 8 vat = ae eee 5 aa
eed eepal | fics wit ere at ; } tee we Ho : ©
S] ao pan ‘on Brn af 4 4 fp
RD a = 2 2. ~ =
° bed : ‘ H : iad Hoh : ‘ '
2 om a7 4p hg Os ae ee ee 1 x He ALL aa ! : : a
o Hos ;
Hoburg. n + ae H pare tl ee i ; tee Hie : : x
: os pat i : H qt : =
Bursvik. ror) aes ii Ss : St : eg : nm
Niis. cs) oe eae ' He Beat teat : i i 53
BP ca a a ae eeu aay: f es i Ce sae ae wi
Grotlingbo. + i ieee ast eae i at : ! ; b ‘ >
i. 5 : oe ae ae ai ; ease ; Mbete sie an tt
Habblingbo. 19 ee ea oe he Seni ee = ae a Het Ay eat ce
Lau. o aie ed eat ee ; toate ie ! on
Linde, Vardhem, | = i 4 eal! aes aie a eS H H ° 2.8 © : 2
Stora Carlsé. i) aot aa aie taal HAiatt endings tlerectice «Heol sitio ; 4 ; i ; 10
Tey oem Teteet | im oi a ae mie atom atin ae j eget meals Fc ip Poe wot ||
neem © He ee He em CE a eal eA ee ma ol Hee
Djupvik in Wksta, = hats ine Sri eae] aS a a (tot ie ere ot tear crs i i
Lilla Carlsé. 4 he es eae on Sa Hf BEE i Sm ae ieaeaat pes
r ; Fae a ee ed ae ee Peete mst icotecret—atin~-t fall = : ; i
Ardre. oo a ee Me ae ea eee eee ee | ie te cgt as : 4 4 10
ae he tan ee Paseencaaie y+ roneay seeding ; fend —
Klinte. é Hogi ht cgi Bt mume at edie Wregaitmmtinar Dit Ot te at Hee ae toe onsen ; tae as
irre arate at erm One tat p Timer es ages Tae foot ‘ heen
Fe UE eee MMR HOT Meter Ry WR mae MRR Be ter dette. weal Ral fk ee eels e aa a 4 Dect
Ostergarn, - et tates eae eek tee me ge to ger ik etic Th SONS SS Hoag WS Cae aerate all elie H Hla
ee er ee ene i rete nian ie Cee Bert: et tices at coat aa yeaah st an Pe
Kriklingbo, © ome ois act matey covaaisbeet Meio Aime pt Uae Beith Sts omni Shs ee at He tl a aos
ae Cant a i Pet, | ate a eee 1, ee 4 ; ;
Westergarn. oo aa aie et ee nia ergs apd Sey Pe 3 pap ia tert eee : ; i ee | a

Brought forward

Euomphalus.
90

PICUTSPL Ms a s<5 aces! occa: cedoew sen nud-pecue ce eee ee cece a eee
Wiatlntsted tins 9. o4i- 288-52. -520s.ne some eee eee tee wes na ea ree

Loxonema Puiures.
BINWOSHM \SOWERBYy secs sos sc bees oS beded, = sears 2 J Seen sees8e
AECETUGLUIN! «Ns 2 .coseee, Faas ee eS eee seer See enn en eee
infuumescens) .j- rece ssasaet Nee Sse ae Soa! So Rds 2d sora Sanwa:
fasciaipin- mss eee eeetan ee. ks slosso Lk sasten. st eee b sees

Strano) Aim pnt aeena nara ee sae ee. 2828s ane cemee seen onan eae

Trochide D’ors. p. p.
Trochus L.

Fam. VIII.

Gotlandicus n. ___.-......

LITT ATVI CENT TRS «ape Senne ee ae ao he kon Sey, BEAR et aN ae nee
ON OULIS "EM ye oe Rees Sate oh cece, een ee ee ce eaten ee eee wee
HOR DETR gest ete 8 ceca oe seen ee See at Sater ee Ree mone
102
103

undulans n. ___-.-

yOnRE TET Lt ie BE eee Se RR EES Se SE ee Seem Senos ecueee

NOAM Cavs Ant ee se Preis ee Rien SNe, RN ey ees sobs OL Sea
MO bMigumd preniinn Ska ee a ee etree re te aoe ct eae
MOGPRolm odinitmns: ec 3- eee nee ee eS
TOD alliving? = 5 Fte8 5 SS ee Re Oe eee
LOB oe Wishyengia gnc. se ose coco nek ge ee Pete ee nae ec
A OOBlamel logis ais. see = ae ene ee ae

Menigesiria hs) Nha ese = ee eee ee ee ee ee ee
astraliifonmis, 0, ice.cc8 costes beasn ghee ooo eect cue eae coe eee
Fam. IX. Umbonide n.

Pycnomphalus n. gen.
ODESUS RNa rs ee tet oe eee ee ere Eanes

acutus n. __.

trochifoxmira’ 1igeees-e pee ce ee ke eee ee ee een

Fam. X. Turbinide Atprr.

Oriostoma Muninr-CHaLMas.
CUSCOTSYS.0 Wisse ccces Sona eee ee ee eee
118
Urcontranitm | ms;cSo5 2s. sock eee ee ee eas See eee
120
121

var. rugosum Sow.

globosum ScHLOTH. _-.

var. sculptum Sow.

Carried forward.

G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND-

' | = 3S
Faro. 2 g & : ” = 3
= ml) eters a iim e|eie
Se joel ae) 2 Le We ee | Sen eee ele
S| 8 ele|s¢ Bot te (eh ee
Ss | 8 ; Siac z
5 =I 3
g? | 98 | cowl] 891 Geto et ares aero eles ep | 7 | 3
memes tle. 7c |, ae all
Bee eee soa peeeres |jeeacse |Pesonco (jostase |PtcSase | oescns a Simms pee || ame
ee Pee een eee Peers | eee eset a Seesen | decease | Sore
Be Pepe) pee ee| ower) | Sena c sebwcny} seeeen | emene=! [fenees— | comeee |) -- clue
Bei reeset Besa | toesecay cosa jf coe= So | o-asa4 | ce oct c weesas | eeneee | lle
c be Co Wiestace 6. ieeeeee G# j|"S=-2ce Bo WieteeeulEa-soenl eee,
pbeeaad| etm eel) See See] he eee lle eed eee eee be be esl oescan lhe
ae oe fioeeare= | peor | acess | Paes c SEN eel ect) (eee beac) Se 5
SSeS | penne | Pesce | ere || eos c ee NN lee ea a c Sestes || sess5))) 3-5-5
Sewers osecee || Bseeeo |l'ceeoc= Paes, c c ey | Pees | Peer en Pero) | 54
See Co se eee atl) Scecorn ress] 6455 c er | eo see pee | ee | | ae
bey se | Wesecee | Senco |raacs— (1) essen (ese eee) oa |e |) =e
Seon fsa [eed ete | eee Pees Posse | ete | oss c Sere es || ane
Sey | remsssae| pee ees eee pein. fecmoco Lime eno c aean=- | ------ || ---.2-
ot ees feomiemey | oee oo Peete (Heese |) cto Oe hosscca Becoees 4 [eco
Sey beam c Seecas || sce c er | ese aos om | Poss aseny pee ee | ee
Sees | ene sed egace oes {yes c c Sos = c c ane | eee
Se | eee esse eee | (meer |e S 4 Ma Scs | ssa ce c wana | ------ | -.--.-
see e Cy eeeeee c Sao | Persaae |[ oso SER | PRESS | ESS [eRe Ae |) oes
Besser |) Sey) iat ass c metre) | eee |) ennee c c Ber Pee |) ee
Beeson soesee Iposceco sesso |feoecos || aso-5 |/icessos || =4--5~ c a = | eel as ee
c c c HO \ossces Feb |) Saar c c c 1 aetna
SS ene tee c Sosoie c c c ac c c saan
Cj) eaecee c (2 es Cee ee a re eRe S| sea |} oc
e c c (em aera eee ell [7-4 c a) Alesse Or | oweee
c c c (fon | Reyamep c b c Gao. | 22a ee
15 | 14° | 15°] 15 | 8 [ees |ea8' | Me] ts | a8 | zo |S

23

n:0 6.

BAND. 19

AKADEMIENS HANDLINGAR.

KONGL. SV. VET.

| es i +4 =
A _—_
| = ;
Solgesaniwees || & a
S °
at) 1S)
4 g H oD
- aE |e , fhe
mn
3
S| >
=y 2 ° Ss * * * * ar
os
co
to | 8 aT
‘Ss °
2 real ee a co ~
ee} Si
wm | ee
° ;
C] aa 1 * * S
Hoburg. QQ ce
p re
Bursvik. 3 I
Niis. bs)] So
Grotlingbo. be sH
Habblingbo. no = ee
:
Lan. & H =
6 o
Linde, Fardhem. | & ° ° 2 58
Stora Carlsé. i) 3 Lig
: *y 8 ol 1) H H
Djupvik in Eksta,.| a eet aa H a
Lilla Carlsé. | ® ont cg~ ier
Ardre, 9) i >
* =} Hee etic al ao H S
Klinte. baal Poa +4 ies in
. eae ae. oe a ee as Rie
Ostergarn. 4 H i ee ; neat Tat
nor vo ven ve 3
Kriiklingbo. é Pettit betel Aeen ta 4 iy
Mahe fe ickas bet = 65
Westergarn. re) eis tien et Hoe E 4

24

G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

122
123,
124
125
126
127
128
129
130
131
132

| 133

154

| 135

136
137
138
159
140
141
142
143,
144
145

146,

147
148

153

154
155

Brought forward

Oriostoma.

Wisbyense n.

eneniifer ns 278 es Acces eee ee eee ee A ees

PROG NT ey Ieee eee aes 2 oA an te ec eee TN

ane natin WARDEN B epee eae feo Bee ne Pe eee

dines tums nie eee 5 sees. os es eee ees

Gelicapul tm) M,\ee<3 es ee en See ey eye Mee

APLC A UMN eee ce sate ee eee See se eee ne NeC NES Cae ey See

Cancel atime: n apes sess. eek eee wee ees ope we ee eee ee a

ISLET SPN) Aan) cog eee RS es ee es ee ed

perversum n.

(Rrachonema) mourn tum T: oe cee see ae a ee ee nee

Eunema Saver.
muricatum n.

spinulosum n

elegantulum n.

var. brevispira n

filistriatum n.

involutum n.

glabrum n

Fam. Xt Phoridex Gray.

Autodetus n. gen.
calyptratus SCHRENK

Fam. XII Litorinidw Gray.

Holoped HALL.

Carried forward

| # | @
Par6. i) 5 =
= ee I = = = 2
Ste | ee) A eS ce eet tee
& = = we = = = @ = = 3.
es | S| 2A eee [Sa eea eeeeaeml
es eal ER aeee a
al aie :
15 14 15 15 8 23 18 16 58 13 10 3
Ee eee (aor co Wee ee Mr et ene |p eee eS al | c eperery
eS eee eee Peseta | A eeeeen| eons if esesl= (Rah) eee el (Ree es | | eee: « (MEME, | Ea =
nnawen f seaanst || eae ee ||| 2 See || eee Gow x23 | pee ||! 55230
seedex.|[Geccve | feseeee a) Shoes | 2 eee | eee |e CO | ee ea a
See | eee c ce = oes c ee ree ial! Ura | ee | NE eR ae
eeaceal|Reoamell| tee qe =|) dese) ote | Pee | es ee ae Leo, ae Seles | RN: | RR 2
Cc Ce Saami CS) © tees c CC. Vase c Cc Ct aS a
eee een bere | saa teem Poa) RR | ee a c Bestest te |
See |) 525-553) b =e || Sethe ee 2 | ee ee ee |
.
Rao! | ese et homscen | eae cee Pes S= e ae a ees a Pe | een aac
Sosa cece Wee 8) Rc a | | |
po ||, -eoore ||| casos | Risse cl pe eee c c sorcist || Scee. c See S| eS
See ncaa eetosoa eee beeen | Meera Wee ion ecsons |) cess c SS |p Peas |
Seen em {| cats ey Nesaeee.)|) Soe a ee I ee ees a Sh ees Pome HARE H.
Sere | ervey | ecocea |e eos lec ceee c Reese ce c Eee Perce ee) lemon
Passe > || esse) cass essen: sses c c Sema | c = ee
Pee ae een. fi en et ic art ale === \-= eee eed! MR Sap Pe
See eee eee en en ee ee |) Sia c Ps Fee || | ees | Vase RE
cen en (eee cote Ea See 2 b ae c Beer ia b eee | eereeesl ras
ees pce ne Seca re tl Way + Se Cc fodhes | oe ed eo eee |
|
coves pecs eest hess htee=ce yf cbe.c. |) coastal ceed eee (Pe peste lee ||
ie | 13 | 17 | 17 | 10 | 31 | 93 | 17 | 68 | 19 | 12 |

25

AKADEMIENS HANDL. BAND. 19. N:0 6.

VET.

KONGL SV.

' 1 ' ' a)
2/a * . . a ; 4
. g <= 3 a “4 i (ea areas
a) 8 A; : : ! Pe ;
Selieees era! | ee she teeta ee.* ue. ey
S ‘ ‘ i Het, etter ia ' Te Seat ea 1 tl eo
2 se| &® : ' i ss ae tigee 1A let eg Ae aes. % fT fae
ay |e fen BR ee ae = ee
2 ' ! H ge t H H ~
al oO Ly * I * ' * * * ' * * * * * , ' * t * * , * * * * * t * * (to)
=a ' : } amt ‘ } }
2 | 3
5 ww Sie a Be |
on S 1 ‘ 1 ’ 1 1 1 1 ' 1 '
S| & / ea = ! t ee rier } So
@ as 2 ~ ete , Hime ee ; \ iy oh Ht * * ! =
Ble i Hie vita i } ie 1a H
na! Ss =
° es et : Hee te an } } : He pa — 244 4 ‘ 5)
e os) ees ‘ Hoe via SO Ee aH ' to ewe H ' oN
H H i H s
Hoburg. Gr) ; ‘ a i s —
a a : i > Wooo
Bursvik. mo = ; j 3 te!
Niis. i ' H
Grétlingbo. Se ‘ H 4 = od
F : H Hee et : ‘lo
Habblingbo. er i = ; Host: 4 i ta
Lau. cs = ie : = Le
Linde, Vardhem. 20) 2 H 9 on ono °o 9 ° i 2 cS) ° ot ne
Stora Carlsé. ~ ! eat Sieh i ; H i ; aia H : nD
ee x 3 ey er ae ; Hams ee Hite eae eect BS itn i =
Pipric in wkete PO te tied PP a vein 37 cane ae caer oe : : is
Lilla Carlsé. 10 H i Hh tea i H ' oe i : H Hee ec)
AER Sa aati mes ee ere eer Fie Ft om ee lt te te Ath Tat ot ' eee ; Kt
Ardre. é SR ate = Di ea ae an a Fe SAR tH a ae eather Cee tree Hie i tee ta H : n
al ' ’ ' ‘ ' ' ’ ' ' ’ ‘ ’ ' ' ’ ' ’ ’ ' . ‘ ‘ ‘ ‘ ’ ‘ ’ '
; ~ Hs athey Gath “ablpmgt tees cet it acl ce aa eee ite ee tae ! ; H inet H aie
Klinte. — He Sa) aie ee ee ear Naas nae iam mesic t gag ies Cee te aS : Hae ae aa et ‘ + HG
, ' 7 ‘ ’ ’ ’ 1‘ ‘ ' ' ' — ‘ ' ' ‘ 1 ' ' x ’ ' ' ' ' ' ‘ ’
z é HH eee ie ett eaSt He fp aie tar am t ! Ht eS Siete oa se Heal
Ostergarn. emma. a wee mee ate t. 2) Re fe he ie Se Stadt Oms toa! ie Woah ie tea cs ese
ir eae Crate qe eT Ve he pee ae att) AG aeelege it : ee a ee ‘ to
Te] Ca Ceres er eee eee Cees ee ee ce cece al
‘ m a eet gt a wees am Hie anaes setae atlas ty oe ta H Relate ites De eara at : + tL ep
Westergarn. 4 Dae ee tae Ss tht Age Demme lie er etiam ogee tot ty tt nat A ' ec th ite Ge AE at i Ho |

Band. 19. N:o 6.

K. Vet. Akad. Handl.

26 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.
2 2)
Faro. Plats |) mies &
a = } 2 i=) 5 a
= Bole] es 2 2 ee ieilae ioe || 2
Be ee | 8] eel) Selif Be dias lien lca aes meet est
BE | oo) eae We | es ieee eed | ea le
3 | 8 ey ae Ale ee El ae ob
3 5 P
Brought forward| 16) | 15 | 179) 17 | LOS) Bi 1 23 17685) Lo) 2s
Holopea.
Wel BG6spenforataimyes st <0 cee 5022555552212 25.2 ies seas Pere ees oe een P| ec ot) Se a ee re | ONS oa ee
Py Ceo BLISS ITA ce 3.525252 ooo ae BI ee ee a we |e eee | ee |e | c | | Wee lear r=
Wel sGiapplanat@ensrnssscess' 2) 25... Lele Lod eS a SN Ee | ee ea ee eee | ee | Gr) | hetsars |eemers Miss,
Fam. XIII Sealaridw Bropertrp.
Callonema Haut.
MO fobesum: jiu’. 2. =... 0S eee Meee ee el EL eee en | |e Se | a | | Eee | oer eee
GO! scalariforme’ n. C2 hes cee es RS Se Oe oh ee | | ee || [ite | [pretties | fees | eee
MGI; teres’ Nyy cpevecenres ee ere Oe a2 oe ee eee inn |e ee | [oe |) Bee em CRY |b Ve I Beirne |e on | {lek 2
W62! regularisin,-2ss 28. 5 aes acest ete =a esd cass oes ea || yl | Pee ea |e | | 7A ese esses | eecee
} WGSrminutaine 2. c-8 ss. sts ede hak ogee eccwack cones oon be clec ee seesccctcee ence welll |e a eT | pear rere aT | ||
Fam. XIV Pyramidellidw Gray. |
Machrochilina Bayur.
G4: cancellata1y-c.<cp-= s-pas~sese-h ewe sno nn he caonecon2ackeweceuanencset cae-chell|llccaeas || Rgonee ll aobocell| tect ace ll esos eed | eee ee | en | | |
WG bulim inane ce - oe sades ok bce eee nc et aewnen se oc en wae ace weer stems eo: Wesccaty | Neeseseul | hoeeee ll Ls semen soceee a | eaten! (eee een |e | | en
WG Omte mes tr etbaan see eee Ce ee eae a ee een oad heen mate came Alp amen || eran eM | eae | Ne eee (mn ed Reinert ay Pre lies wate |) Saba || Sea
Fam. XV Subulitide n.
Suwbulites Conran.
llGviaventricosnsiMebantieist be tah SUE Pe Ty eee leas Diy eS ek ll eet | ripe, | ees | eee a
ES Gventricosusavarh cUrVUSshc clk k a ew eee Ce he || | a lee | ese | ee Coe eee (oT | See | ee | een
GO Vabtenuatie: snes. Sateen 9 Eee =: Mite See ad es ah Of a eel lee Bey | ee (aga es ee, | eerie c ae |i Ss oes | ee a
Euchrysalis Lavuse.
TVOMineolata: ny 2.20.22 eect c eo eh weeks decks ec ees a a a | |e
Onychochilus n. gen.
All pMy aan Nass ee, eee Ree ROR. Sux Soe AT A tt LS UE ell S| S| | Oh Wire sale ce ee ee
72 -reticulatu ms’ n.2\.._o.-25ic2 02202 8 col ccna owes Sewell | | |
Ae scocnleatumy nyt eae vek =e Re tN oe AE eee ne oe || Rae ee |e | | ee Gis ee |
ADDENDUM.
Murchisonia. |
U7A: paradoxa, nyacs.2-.2e= thee. eee Se ce el ee | Re |e | eee ese ee | ee
16 | 17 | 17 | 18 | 10 | 34 | 95'] 18 | v7 eo) ie | & 18

KONGL. SV. VET.

AKADEMIENS HANDLINGAR.

BAND. 19. n:o 6.

27

| & oe Et Stratigraphical distribution.
eager | Oe gE | Si Bul Ea eicy
S rE & x = a. 5 @ = ea es} jaa} | d
= = a re Lee ~ = ek = = ZA 5 Ss Only found. Common
a Br oS S = 2 5° Q Bee | ss =a = or Cy = in to
2 oR SF @ & =, 5 iy fi uel a3 Y — om | |
ia] o 5 = & = i>} o = Is * =
5 3 : S: a S: = S ° | all |
= a a b Co eee ab be
13 8 21 23 8 5 27 8 35 5 10 5 4 13 6 28 10 | 67 26 8 16
ceseeed| — -csey/ 2S aeee |b Seca h peceeen seers dl [aoe el Meeece eed | eaee fale peaked ee er ed | cee) eee ie ee oe * 1680) as
sosesell) cosas |] ceases] 5-8 Sod ease | eee | eee eee 225] eee | ee Roe eee eee (eee 1 OO | Uae oe VP nee Oe CY ocean ||P Peasy eens
csegse || cseess |] corcce ] eeeces|| szccdee || eesace || Meeeeee | lessee line coe || eee Meeeeetl UeEeremty ie eae 1 oH Sean | ee | SO} cee | Re eee (ene
|
i}
Bes ee esi eo 92 lca ee ES EE eee ee eee hee) a i cPanel eer cra Doe
czecee || conceal]. césce=||!) sedate || cacenall) tetse| eesete || weseceet || Beeceece || Hecee cen P eeceeel INeeeeren Daseeeeey (et ane (ean (a * Bie SN |enbe ellie
|
oceces yp cesesey ees s 255) TRS oe pie eee eng |e | eee Sere eed pied na ate eat ea ted weeees a me Seat Sy =e * Poee ss Pa ete apal
=Aacce’|) cnet [ee ta le comes |g ae et | eeszex || cores) | seccee a Seren eee e Sciee | eee * Seezee |) carec~,|) 8. 2- | Perea eee
soaces || ccoseell ue sse2s|| eee fe ee | ae c ee lll ht ake eee te eee | al eal Mi ace db ars | ele Psa (et (a
|
Booed econ: pa eeem, eee (remy) OF yee Ak 2 lif eee c pore ee an | eee || eee |peeen | sets [ber ee cles WP aie fee aae ter cce ot) ca ed
Beene Recor abet. (Pad Ei el Ue c RRR SEE | Prrtce 7-5 | ee er| Pee Py PSS AEC AD SEARS. RS PRS ae ent | Pa
eregne ||) seéceey) eecee || Grease i) sceecooi) cecaeeul, Soret @ cctese Ih Sacchi) Sees eel eset a ll ee le et BSE |) ee * oy Pe hve) yaen
CLI | erect eee re ee Sens eke meee Meso |) aaa ccailllraceeee aye hocaee || Roscoe |Pmsccae oul! SclaceAI ESS cee | RS) CARE TOD Be Crile | Ree
oes If comand. S-caeSd) ascent e eee cece cs | eee Hee ears |e cee ae eee neel ere Seat eeeeemed Ib OmneaY cere eee ee Lee) Me ee * poh a3 |(t hehe AIEEE ed
An eee eee ees ee cs | saa Peer Elec sore! eect Bo sae|lveweete |] ccpe andl) ee |y) es ey pees |) eee Te eaceee * | weeee2 0 seeeee
oatee? || sae |tetoceed | hacen en eeceeaetl (EEE on | eee |r Cc races) Corcaea| eseceeca teresa] eacose | eeceesel Peace ||: eescee Ed ete |) ee See | ae ee
| |
| | |
ee at ol oe eee eet Te oA a a eee ee accked |! Miweme cm [f ooceeet |) fe eeme fl Sancee" |! Woc cue |! Soeoea I) caeece | enetcc |) caccee * cones Suctee ade me
eee ||| cecec lp asicee | cee tae eee ey ee eee (ees c Pees eee || Ab 4] ad aes «| ee Nee eel ee Fg OLN (PEYEES|
epee ||\Yareoo |) -sseeee Sere eae ence eee eee | cree ee c Be asc ch ||| seems eee eed | EePeeed meets cal eee | | ees eel (ecm Ear peeaee || Peery ese
ee re ee ee ewe eel Le es |S = fe 8 c Beare Sees LI ee ge a ee |e eee pee | ee
15 8 21 23 8 5 27 8 42 15) 11 5 4 13 6 29 12 81 27 S, 16

28 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

far as Klinteberg, but as they mostly are scarce there and frequent in the north they
may be considered as North Gotland shells.

Only five species are common to the strata over the whole island and conse-
quently the most characteristic species of all Gastropoda. These are Platyceras cornu-
tum, Tremanotus longitudinalis, Pleurotomaria alata, Oriostoma sculptum and Autodetus
calyptratus.

With the exception of the minor faunal districts which have been sketched above,
such as Sandarfve and Djupvik, there are in other respects no obvious grounds for
discerning larger, faunistic divisions, as was attempted in my paper on the Brachio-
poda of Gotland ‘) some years ago. There are so many characteristic forms common,
such as Autodetus, Craspedostoma and Tremanotus. Moreover, it is generally the
case that distinctions based upon the occurrence of the species, are sooner or later
effaced in the same degree as the material for study increases. It is then evident, that
all such considerations have only a relative or transient value and properly speaking
are only valid for the time they were made, as each year brings new forms and mo-
difies older conclusions. New species are discovered and those formerly found are ob-
tained from localities and strata where they were unknown.

As to the vertical distribution of the species as many as 29 have hitherto been
found exclusively in the lowest or shale beds, signed a on the synoptical lists. It
has not been possible, at present, to ascertain the succession of these species within
the shale beds or if there really be zones of vertical distribution within the range of
the more than hundred feet it comprises in thickness. In common with 6 it has besides
nine species and with both b and ¢ 27 species and contains thus in all 65 species.
The next stratum 6 is nearly as rich, although having only twelve species of its
own, and in common with @ nine species, common with both @ and ¢ 27 species and
with ¢ alone sixteen species, thus in all 64 species. Richest of all is, however, the
third stratum c, with so many as 81 species peculiar to it, which in addition to 16
common with 6 and 27 species common with both a and 6 make up the sum total of
124 species.

With regard to the occurrence of the 25 genera, of which the gastropodan fauna
consists, in the different strata, there are some, as Tryblidium, Paleacmea, Trochus,
Pycnomphalus, Craspedostoma, Holopea, Euchrysalis, Macrochilina and Onychochilus,
which are restricted exclusively to the highest strata. Some again, as Oriostoma, are
most abundantly represented in the uppermost strata, though there are also species of
it in the middle limestone and the shale.

It may be questioned whether not any evidence is found of mutations in such
species, which occur in several strata, or in those, which have been found also in
younger or older formations. Such changes, also indicated through the presence of
nearly related species or varieties in older or younger formations, have most obviously
occurred in the following species, which are now enumerated. The matter is more
closely considered in the description of each species.

1) Bidrag till kinnedomen om Gotlands Brachiopoder. Ofvers. Vet.-Akad:s Forhandl. 1860, p. 337.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6.. 29

Tryblidium reticulatum Lon.
Tryblidium unguis Lom.
Platyceras cornutum His.
Pleurotomaria limaia nu. n.
Pleurot. elliptica Hts.
Pleurot. bicincta Haut.
Pleurot. labrosa Hau.
Pleurot. qualteriata ScuLotu.
Euomphalus Gotlandicus n.
10. Oriostoma rugosum Sow.

11. Subulites ventricosus Hawn.

In regard to the distribution of the Gotland Gastropoda beyond the limits of
that island very little is at present known. As common with the nearest strata of Osel
and Estland the following species have been annotated: Tryblidium wnguis Lom, Platy-
ceras cornutum His. very common, Pleurotomaria elliptica His., Pleurot. bicincta Hawn,
Oriostoma angulatum Wautu., Or. sculpium Sow., Or. discors Sow. very common, Pleurot.
planorbis His., Autodetus calyptratus Scurenx, Pleurot. qualteriata var.

From the Upper Silurian strata of Seania at Bjersjélagard and Klinta I have
seen Platyceras cornutum His. Platyc. enorme Lixpstr., Autodetus calyptratus SCHRENK
and indeterminable nuclei of Murchisonia, Pleurotomaria and Bellerophon.

From Norway, I have only seen the few following species:

Conularia levis n., Pleurotomaria elliptica H1s., Oriost. globosum Scutotu. In com-
mon with England the following species have been found viz. Platyceras cornutum H1s.,
Platyc. spiratum Sow., Pleurotomuria limata nom. noy. (= Euom. carinatus Sow.), Pl.
labrosa Haut, Pl. alata His., Pl. Lloydii Sow., Pl. bicincta Hat, Bellerophon trilobatus
Sow., Lowxonema sinuosum Sow., Oriostoma discors Sow., Or. rugosum Sow., Or. sculptum
Sow., Cyclonema carinatum Sow.

With the rich fauna of Bohemia not a single species can, for the present, be
recorded as common. I have had access to a collection of 65 species of Bohemian
Silurian Gastropoda, acquired by the State Museum of Sweden from the late M. Scnary
of Prag, and I cannot find in it a single species to identify. Euomphalus pulcher
BARRANDE comes very near to Oriost. Roemeri and Euom. simplex Barr. near to Oriost.
sculptum Sow., but they are probably different.

From the Silurian formation of Podolia and Galizia Friepr. Scumipt in »Einige
Bemerkungen tiber die Podolisch-Galizische Silurformation» (1875) p. 17 enumerates
six species of Gastropoda, but of these Euomph. (Pleurotomaria) alata is probably the
only one which can be considered as identical.

Von Aut gave in 1874 a list of Silurian Gastropoda in his work »Ueber die
palwozoischen Gebilde Podoliens», page 31, amounting to 14 species, but as I have not
seen a single specimen of them, I can not with any certainty identify them with those
from Gotland.

Of N. American Silurian Gastropoda I have found as identical, Platyceras cornu-
tum His., Pleurotomaria labrosa Haux, Pleurot. bicincta Hauy, Subulites ventricosus Hau.

Pleurotomaria bicincta Hauu, Pleurot. elliptica His., Tryblidium unguis Lym. occur
in the highest strata of the Lower Silurian of Estland and Pleurot. elliptica, Pleurot.
qualteriata are common with the Orthoceratite limestone of the Lower Silurian of

ere Det YN SH

30 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Sweden. Upwards, into the Devonian strata of France and N. America, only the fol-
lowing species is passing, viz. Pleurot. labrosa Haux, also found in the »Devonien in-
férieurn at Néhou and in North America in the Lower Helderberg rocks. Platyceras
cornutum His. can in some of its varieties scarcely be distinguished from the Eifelian
Pileopsis prisca to which it at all events stands in very close relation. ellerophon
trilobatus Sow. also seems to be a species which has continued in the Devonian time.

Zoological characters of the gastropodan fauna.

If we except Chelodes and the genera Subulites, Euchrysalis and perhaps Onycho-
chilus, all the other belong to the large section, which on account of the circular
peristome has been called that of the Holostomata. Chelodes as one of the Chitonide,
belongs to the strange order Placophora. Subulites, Euchrysalis and possibly also
Onychochilus again exhibit such characters in their aperture as to entitle us to place
them with the great order Siphonostomata, hitherto regarded as of mesozoic origin
and entirely unknown in the paleozoic formations. It cannot be denied that the evi-
dence offered further down supports this conclusion and that it probably shall be
corroborated by further observations. If then, as I suppose, Subulites is one of the
Siphonostomata, these have originated much earlier than in the Gotlandic Silurian, as
there are well preserved species of that genus in the Lower Silurian strata of Dale-
carlia. Subulites nitens Lom (in Fragmenta Silurica p. 14) occurs already as early as
in the Lower Gray Orthoceratite Limestone of Sjurberg, where besides this no other
forms of the same order are known. A larger species, probably Subulites (Helicites) utri-
cularis WAHLENBERG (Subul. elongatus PorTL. according to Fragm. Silur. p. 13), is found
in the uppermost stratum of the Lower Silurian of Dalecarlia, the Leptena limestone.

Of the fifteen families represented, as many as twelve are also recent. It must,
however, be conceded that it is with great diffidence that several families, such as the
Litorinide, the Pyramidellide, the Turbinide have been introduced in the lists. Of
the 25 genera again, the majority or 23 are considered to be extinct and only two,
Pleurotomaria and Trochus, still persisting. The former genus, rich as it was in the
Silurian times, had not then reached its acme, which was attained in the Jurassic seas
and now it has dwindled away to four species in the recent seas. Together with Mur-
chisonia it gives to the fauna of the Gotland Gastropoda its chief character, their 54
species making nearly a third of the whole fauna. Like Pleurotomaria there are other
genera, the systematic place of which cannot be contested. The beautifully preserved
muscular scars on the inner side of Tryblidium certify their near connection with the
recent Patellide. Chelodes with its numerous very characteristic plates belongs in all
probability to the Chitonide. The numerous Oriostomata, forming such a prominent
feature in the fauna, testify through their operculum and their nacreous interior strata
to their relation with the Turbinide. It is also very likely that the strange Autodetus
is an ancestral form representing the modern Phoride, the presence of which
family has already been observed in the Devonian strata. But instead of attaching
other objects to its shell as its presumed descendants, it fixed its own shell with the
apex to other bodies. Of the occurrence of such an archaic from as Dentalium, nothing

KONGL. SV. VET. AKADEMIENS HANDL. BAND. [9. N:0 6. 31

as yet has been ascertained. A few tubes from the shale beds of Wisby and Oster-
garn might possibly once have appertained to that group, but their imperfect condi-
tion precludes identification.

As genera especially characteristic of the Silurian beds of Gotland, may be men-
tioned: Craspedostoma, Onychochilus and probably also Pycnomphalus, though it is
not certain whether the last does not occur in England and Oesel, but referred to the
genus Platyschisma in a conception which is not that of the first author. . Autodetus,
which is spread over the whole island, occurs also on the neighbouring Oesel, though it
is uncertain whether so common there as on Gotland and not recorded from any other
Silurian region except Scania. As characteristic of the Upper Silurian formation in
general may be annotated Chelodes, which has also been found in Bohemia, Tremano-
tus, Cyrtolites and Subulites also known from N. America and Canada, Subulites also
from England, and Tryblidium found in Estland and Canada.

Concerning the many paleozoic genera, of which I have appended an Index in
the end of this memoir, it depends much on individual opinions, as to what genus these
old fossil shells are to be referred, but it is evident that it is highly futile to establish
the genera only on a single and variable character. When comparing large numbers of spe-
cimens belonging to the same species and collected in the same locality the great variabi-
lity in the form of the aperture, the columella, the height of the spire, the umbilicus, will
be evident, and it is only necessary to remind of such forms as Platyceras cornutum
to discover the wide range within which sume species vary, chiefly those which have
a large horizontal and vertical distribution. In almost the same degree Cyclonema
delicatulum varies with high or low spire, slender or ventricose whorls, with open or
closed umbilicus.

Among structural peculiarities ought to be observed that in the genus Euom-
phalus, as it has been long known, the shell, in the rule, near the apex or in the
oldest whorls, is divided into one or several compartments or chambers by concave
diaphragms, without, however, having any communication or sipho between them. The
chambered apex has very often through the fossilisation become deciduous and the
blunt end indicates the place, where the partition once traversed the shell. In Murchi-
sonia, Loxonema and a presumed Trochus, Tr. gotlandicus, the apex is filled with a
compact mass of calcareous matter quite as in the recent Magilus.

The peculiar and cellular structure of the external walls in Autodetus is a feature
well deserving attention. In a few genera, as Platyceras, Pleurotomaria, Euomphalus,
there is a tendency in several species to form scalarid varieties and in some species
all specimens found have assumed that peculiarity in growth. In the large genus
Pleurotomaria it is easy to follow the morphological changes which the characteristic
slit band is subject to, from a concave groove to the large, thin lamina in the group
Alate. In respect to the sculpture of the surface I have called the spiral lines, keels
and ridges, which run from the apex to the aperture for longitudinal, as they follow
the shell in its whole length, and, consequently, those intersecting them are to be
denominated transverse. Some authors call all the later for lines of growth. But
besides the real lines of growth or the old apertural lips, which are conspicuous by

32 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

their lamellar edges, often uneven and at irregular distances from each other, there
are fine and elevated, as it were, ornamental lines. These do not always run parallel
to the lines of growth, but cross them obliquely in some species, as Pleurotomaria ex-
quisita and Onychochilus cochleatum. These elevated lines of varying size are in
several species replaced by sunk and narrow grooves. It would then be proper to
distinguish between lines of growth and ornamental lines, which are formed indepen-
dently of the former or coérdinate to them.

Through the presence of certain genera the following conclusions may be drawn
as to the character of the fauna, of which they formed an ingredient and consequently
of the natural conditions of the sea in which the including strata were deposited.

1. The fauna of the silurian beds of Gotland was a littoral fauna. Such genera
as Chelodes and Tryblidium make this conclusion valid. The Chitonidx, to which
Chelodes belongs, live now generally down to a depth of 25 fathoms, though some
small ones have been found exceptionally at 100 fms. Tryblidium is a nember of the
group of the Patellide. These are in a still higher degree shallow water shells, living
near the shore on seaweeds and rocks, and the occurrence of the Tryblidia is sugge-
stive of the former presence of alge, on which they might have lived, though no traces
of these are left. It has been said*) that the Upper Silurian shales of England through
their fossils and the nature of the shale itself make it evident that they have been
formed in a deep sea. Since the explorations of the later years the range of the deep
sea region upwards cannot be considered higher than 400 fathoms. But already at a less
considerable depth there reigns, as has been shown, an almost absolute stillness in the
water and the motion of the surface cannot influence the bottom at a depth below
40 fms. Occasionally, at more exposed coast lines, as near New Foundland the bottom
has been disturbed to a_ still greater depth, when violent tempests have raged, but
this is of course exceptional and the traces of the disturbance must again, during the
otherwise prevailing calm be effaced through new sediment.

In consequence of what has been advanced above, shells imbedded at greater
depths could not show signs of having been subjected to any abrading motion of
the waves. Now, the fossils enclosed in the shale beds of Gotland on the contrary
attest in many instances by their abraded condition that they have been tossedabout
by the waves and, consequently, have not been imbedded in a bottom of any consi-
derable depth. The great movement in the sea, where they lived, is also evident through
the shells sometimes having been broken and then mended. Thus there are specimens
of Pleurotomaria labrosa from the shale of Westergarn, showing such a break in the
body whorl, which had again been repaired during the lifetime of the animal. The
superincumbent limestone strata are for the most part conglomerates of corals and other
fossils, and, when fine grained, the limestone consists entirely of a sort of calcareous sand,
the grains of which are comminuted shells and corals. It thus highly resembles
the limestone, which is forming now a days out of similar material along the shores
or on the beaches of the tropical regions for instance near the Westindian islands.

1) Fucus, Welche Ablagerungen haben wir als Tiefseebildungen zu betrachten? in »Neues Jahrbuch fiir
mineralogie ete.», II Beil. Bd. 1883, p. 565.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 33

It must have been in some sheltered bights, where a calcareous mud found stillness
enough to allow it to settle down, that such deposits as the fine grained limestone of
Sandarfve, or Samsugn with their numerous and beautifully preserved shells originated.

In general the shells were middle sized, only a few, as Pleurotomaria valida,
or Pl. cirrhosa attaining a greater size. Fragments of an undeterminable shell from
the shale of Gnisvird attain in the height of the body whorl alone 82 mm. and in
breadth 98 mm., this being the largest fossil shell, known in Gotland. This size and
the comparative rarity of tiny shells also militate against any assumption of great
depth for these forms, as only small sized species have been dredged up from the
abyssal depths.

2. The fauna had a tropical character. In consideration of the great numbers
of Pleurotomarie, Trochi, Turbinide and the large Pteropods the assumption of a
tropical character of the fauna may seem justifiable.

Older descriptions of Gotland Gastropoda.

There has been no want of workers in this field, as we can learn by a review
of the memoirs of the authors previous to this. The first time any mention has been
made in print of the Silurian Gastropoda of Gotland was when MacGnus von BroMeLi
published the »Articulus secundus» of his »Lithographia Svecanay'). He there, pages
28—37, enumerates and summarily describes 21 different numbers of fossil Gotland
Gastropoda. But as both the descriptions and the figures are very unsatisfactory —
the originals being mostly mere nuclei — I have not been enabled with any degree of
certainty to identify more than a few. Thus N:o 5, page 30, and N:o 6, p. 31, in all
probability are specimens of Pleurotomaria alata. N:o 21, p. 36, is an Oriostoma and
probably Oriostoma sculptum Sow. In N:os 26—27 we see nuclei of Murchisonie and
N:o 27 may be M. attenuata.

Linnzus has left no descriptions of any fossil Gotland Gastropoda. In the relation
of his travel on Gotland in 1741 he only mentions them in passing. On page 189 he
says: »Petrificata plackades af oss hela timarna pa wastra Stranden (af Kapellshamn),
ibland hwilka woro ganska manga Conchitx striate och Cochlita»....i. e. »Petrifica-
tions were collected by us for several hours on the western shore, amongst which
were a great number of Conchitx striate and Cochlita»...

Witnetm Histncer began his long, honourable and meritorious activity as the ex-
plorer of the geology and palwontology of Sweden so long back as in 1789 at the early
age of 23 years with his first memoir and in 1798”) he published »Minerographiske
anmarkningar ofver Gottland». On page 286 he enumerates with other fossils only a single
»Turbo? i pisolit kalksten», In 1808 »Samling till en mineralogisk Geografi é6fver Sverige»
was published and there he only recapitulates the remarks in the preceding paper. The
number of Gastropoda accepted by Htstncer was raised to ten in his geological de-

1) In the »Acta Literaria et Scientiarum Sveciz», Vol. III, Upsala 1738.
*) In the Transactions of the R. Swedish Ac. of Sciences.
K. Vet. Akad. Mandl. Band 19. N:o 6 o

34 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

scription of Gotland (Gottland, geognostiskt beskrifvet in Vet. Ak. Handl. 1826, p.
311). He enumerates 5 sp. of Helix (= Oriostoma) and 4 of Turbo, of which 8 had
been some years ago described and denominated by Wantensere in the memoir which
further down shall be taken into due consideration. Himself he there only added
Turbo sp. and Turritella meaning nuclei of Murchisoniz. In the translation of his
»Mineralogisk Geografi» in German by the renowned chemist Fr. W6unrER in 1826 the
eight Helicites and Turbinites determined by WantenperG are also enumerated on p.
228. In 1828 he published again in the fourth part of his »Anteckningar i Physik och
Geognosi» the description of Gotland, which he gave in the Transactions for 1826,
almost verbally with only a few additions. Thus there is the first figure, tab. VI f.
3, delineated as well as the others by Prof. P. F. Wanieere of Murchisonia compressa n.
and of Pleurotomaria planorbis His. tab. VI f. 2, then named as Turbinites centrifugus. On
tab. VI f. 6 there is under the name of Turbinites a variety of Platyceras cornutum.
Helix obvallatus had been removed from the Gotland fossils and the number of species
thus changed to nine. In 1829 »Esquisse d'un Tableau des Pétrifications de la Svede,
distribuées en Ordre Systématique» appeared, containing 11 species, the same as before with
addition of Delphinula funata Sow. (= Oristoma sculptum Sow. et others), D. subsuleata
His. (= Or. globosum Scstors.), Euomph. substriatus His. (Pleurot. planorbis Hs.),
Euomph. costatus (a cephalopodous shell of the genus Trochoceras) and Turritella cingu-
lata Hts. The names Delphinula and Euomphalus were then employed for the first time
by Histncer. In 1831 a new description of Gotland is given in the fifth part of »Anteck-
ningary, and we there again find the same eleven species as enumerated before. But
in fact there are only nine, as Euomphalus costatus is a Cephalopod and E. substriatus
and centrifugus later by Hisincur himself were declared to be identical. New figures,
good for the time, were given of several of them.

A new edition of »Esquisse d'un Tableau» was published in 1831 also with 11
species, the same as before.

Hisincers greatest Paleontological work, »Lethwa Svecicay, is commonly cited as
published in 1837. But it seems that a part of it, from a quotation of Brown in Vol.
3 of his »Handb. einer Geschichte der Natur, Nomenclator Bd I, p. XL, where Ninsson
is evidently an erratum for Hrstncer, was already published in 1836 under the title
»Icones petrifactorum Sueciw, Fasc. I, tab. I—X., Animalia articulata et Mollusca Cepha-
lopoda. In the Lethwa he describes 13 species, to which are to be added one more,
from the »Supplementum Secundum» to the Lethwa 1840, thus making a total of 14
species, when Inachus costatus is excluded as a Cephalopod. These are as follows, viz.

Euomphalus cornu arietis = Oriostoma discors Sow.
Eu. alatus = Pleurotomaria alata.

Eu. cequilaterus = Pleurotomaria zquilatera.

Eu. catenulatus = Oriostoma rugosum Sow.

Eu. subsulcatus = Oriost. globosum ScHLora.

Eu. funatus = Oriost. sculptum Sow. & O. RoEMeERt n.
Eu. supra angulatus = Oriost. angulatum Watt.
Inachus angulatus identical with the preceding.
Inachus sulcatus = Pleurotomaria planorbis Hts.
Turbo striatus = Cyclonema striatum.

Qe

e
[ub

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6.

Turritella cingulata = Murehisonia cingulata p. p.
Turritella attenuata = Murchisonia attenuata.
Pileopsis cornuta

= Pls aye
Pil. suleata t= Platyeeras cornutum.

There are in reality thus thirteen species described by Hisincer in the Lethwa,
when two out of the fourteen are identical with others and one, E. funatus, comprises
two different species. Nor has this number been increased in the last publications of
Histncer, in the sixth part of »Anteckningar» and in »Férteckning ofver en Geognostisk
och Petrificat-Samling fran Sverige och Norige», printed in 18141. There is, however,
the important corrections made that Turitella cingulata is considered to be a Pleuro-
tomaria and that Murchisonia compressa is separated from it and referred to separa-
tely as »Stenkaérnor af Turritellor», Leth. pl. 12, fig. 6 b.

In »Die Petrefaktenkunde» by Scutornem (1820) there is only one of the
the Gotland species described on page 162, Trochilites globosus, the type specimen of
which I have had occasion to examine through the kindness of Professors Bryricu
and Dames. It is the same that somewhat later was called Euom. funatus by Sowersy.

GrorG WAuLENBERG describes in his »Petrificata Telluris Svecane», published in
the »Acta Soc. Scient. Upsaliensis (1821), p. 68, Turbinites cornu arietis, which SowERBY
had already called Euomphalus discors and further

Turbinites alatus Wau. is = Pleurotomaria alata.

Helicites catenulatus (p. 72) is = Oriostoma rugosum.

Hel. supra angulatus is identical with

Hel. angulatus = Oriostoma angulatum.

Hel. equilaterus = Pleurot. wquilatera.

Hel. obvallatus »occurrit in Gotlandia rarius» = Pleurot. qualteriata p. p. ?
Hel. obvallatus WAHLENBERG is different from Pl. qualteriata.

WaAHLENBERG thus described in all six species, which were later adopted by
HIsINGER.

Professor N. P. Ancetin, when a student of the University of Lund, distributed
small collections of Gotland fossils under the title: »Museum paleontologicum sveci-
cum» and a list of these is printed in the Danish »Naturhistorisk Tidskrift af Kroyer»,
2° Vol. 1838. Amongst the 50 species there mentioned, we find Huomphalus cornu
arietis (= Oriost. discors), but ANGELIN’s specimens are Oriostoma Roemeri, Hwomphal.
alatus His = Pleurot. alata and Littorina? striata n. sp. In the existing copies of the
»Museum» no specimens of the last species have been found and consequently the iden-
tity cannot be made out. In his works on the Paleontology of Sweden ANGELIN has
not given any estimate of the numeric value of the Gastropoda. But he seems to have
inentioned as his opinion to Barranpe ‘') that the Scandinavian Upper Silurian beds
were not so rich in these fossils as Bohemia, where Barranpr then considered that he
had 200 species, a number which is now manifold increased.

In his paper »On the Silurian Rocks of Sweden» *) Sir Ropertck Murcurson also
gave a sketch of the geology of Gotland. On page 29 he enumerates the following
nine species of Gastropoda, viz.

1) Paralléle entre les dépdts siluriens de Bohéme et de Scandinavie, p. 59.
*) Quarterly Journal, Geol. Society of London 1847, p. 29.

36 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Euomphalus discors, rugosus, funatus, sculptus, carinatus, alatus (Pleurot. alata),
Turritella obsoleta, Murchisonia corallii, and Turbo corallii. The three last mentioned
I have not been able to identify, as they have not been found in any one of the
collections where Murcmison and Verneuit in London and Paris have deposited
the fossils they brought home from Gotland. As to Eu. carinatus Sow. I have through
casts of the original specimens, received from Dr J. G. Hinpe, ascertained that it is
identical with the Gotland fossil described further down under the name of Pleuroto-
maria limata, as the name Pl. carinata was already before preoccupied.

G. von Hetmersen visited Gotland on a Geological tour in 1845, but it lasted till
1858 before he published a memoir on his observations, entitled »Geologische Bemerkungen
auf einer Reise in Schweden und Norwegen». He enumerates in all 10 species: Ewomph.
discors, rugosus, funatus, carinatus, alatus, catenulatus, Turbo striatus, Turritella cingulata,
Murchisonia corallii and Natica inflata. Of all these the last from Klinteberg is the only
addition to those former known. He does not mention the author of that species, but it
is likely that he thereby intended to designate a species described by F. Ap. RozmEr
in »Versteinerungen des Harzgebirges» tab. 7, fig. 8. Of all species found on Klinte-
berg there is none but Platyceras spiratum which comes near to Rormers species, though
this is many times larger. I think then that Hetmersens N. inflata must stand as a
synonym to Pl. spiratum.

Frreprich Scumipr made his researches on the paleontology and geology of Got-
land in 1858 and published the results during the following year in a pamphlet, entitled
»Beitrag zur Geologie der Insel Gotland» *). He enumerates 22 species of Ptero-
poda and Gastropoda. But his Euomph. cornu arietis must be removed, as he also
mentions E. discors and his Patella sp. has since been found to be identical with
Pholidops. Then there remain 20 species and they are:

Conularia Sowerbyi = Con. cancellata SaAnps.
Theca anceps = Platyceras enorme.
eed = Platyceras cornutum.

Bellerophon dilatatus *. 2
Belleroph. aymestrensis *.

Pleurotomaria articulata = ? Murchisonia moniliformis n.
Murchisonia cingulata = M. compressa nu.

Turritella obsoleta*.

Euomphalus catenulato aff. *

Euomph. sculptus = ? Oriostoma sculptum Sow.

Euomph. catenulatus = Or. fugosum Sow.

Euomph. funatus = Oriostoma globosum ScuLoru.
Euomph. discors = Or. discors Sow.

Inachus sulcatus = Pleurotom. planorbis H1s.

Inach. angulatus = Oriost. angulatum.

Turbo striatus His. = Cyclonema striatum.

Trochus helicites =? Pyenomphalus acutus.

Troch. coelatulus M'Coy *.

Capulus calyptratus Scurenk = Autodetus calyptratus.

Biassy gives in his Thesaurus Siluricus, 1868, in the lists of Gastropoda some
Gotland species, which he copied from former authors. He has in all 30 species

1) Those marked * I have been unable to identify.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 3

of Gastropoda from Gotland. But 23 remain, when seven are suppressed as partly dupli-
cates ') and partly depending on misapprehension of the German terms of HELMERSEN y.
These real species are in the main the same as given by Murcuisoy, Hetmersen and
Scumipr and need not again be enumerated.

Finally in a small paper »Nomina fossilium siluricorum Gotlandix» published in
1867 I gave the names of 23 Gastropoda, but in reality there are only 19, as Eu.
cornu arietis must be united with E. discors, E. supra angulatus with Inach. angu-
latus, Inachus costatus removed to the Cephalopoda and Acroculia suleata united with
A. cornuta. The remaining 19 are:

Name in the present

memoir.
Macrocheilus sp. = Pleurotom. valida n.
Turbo striatus His. = Cyclonema striatum His.
Trochus sp. = Tr. gotlandicus n.
Euomph. alatus = Pleur. alata WAHLENB.
Eu. discors = Oriostoma discors Sow.
Eu. equilaterus = Pleur. equilatera Waut.
Eu. catenulatus = Or. rugosum Sow.
Eu. subsulcatus = Or. globosum ScuHLoru.
Eu. funatus = Or. Roemeri n.
Inachus angulatus = Or. angulatum Want.
In. sulcatus = Pleurot. planorbis Hts.
Pleurot. balteata = Pleurot. labrosa HAL.
Holopella = Loxonema sinuosum Sow.

Murchisonia cingulata = M. compressa p. p.

Murchis. attenuata His. The same.

Trochita calyptrata = Autodetus calyptratus ScHRENK.
Acroculia cornuta His. = Platyceras cornutum Hs.
Bellerophon dilatatus = Tremanotus longitudinalis n.
Subulites sp. = 5. ventricosus Hat.

To these must be added one more, viz. Theca sp., which was regarded as a
Pteropod, but is identic with Platyceras enorme, and thus the number of species known
in 1867 amounts to 20,

At the outset of this work only 20 or at the highest 23 species thus were known.
The great increase is due chiefly to the material which had been accumulated during
a long series of years in the Palwontological department of the Swedish State Museum
of Natural History at Stockholm and the main part of information and most of the ori-
ginal types for the figures have been derived from that collection. But in preparing my
work I have also been fortunate enough to have received contributions from many in-
stitutions and naturalists who have lent me specimens or whole collections for study and
in other respects rendered me much valuable information. Prof. Waumsrrpr and Dr G.
Hotm have sent me all specimens I wanted from the Cabinet of the University of
Upsala, Prof. LinisesorG has given me free access to the Marklinian Collection in his
charge; the late lamented Dr G. Liynarsson, his successor Dr A. Tutiserc and Hr
von ScuMALEnsve have kindly lent me specimens from the Geological Survey of Sweden;

2) Acroculia sulcata, Euomph. catenulatus, E. cornu arietis, Nat. inflata, Murchisonia articulata.

3) Brassy did not see the meaning of HetmersEN, when the latter in his lists has »Turbo (Steinkern)» etc.
and Bicssy wrote »Turbo Steinkerni» and even »Huomph. Stinkerni»,

38 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND P'TEROPODA OF GOTLAND.

Professor B. LunpGren has sent me specimens from the Museum of Lund and Lector
STENBERG from the Museum of the town of Malmé, Prof. Jounstrur in Copenhagen
has sent me from the Mineralogical Museum of the University the whole collection of
Silurian Gastropoda of Gotland formerly made by Anggun and others, Dr L. Kormopm,
O. A. West6d and M. Kuinrperc have lent me specimens from the Museum of the
College of Wisby and also from private collections. From the Academician Friepr.
Scumipr I received what he had collected in Estland and Oesel. Messrs Joun Gray in
Hagley, Joun E. Ler in Torquay, Henperson and James Simpson, both in Edinburgh,
presented to the State Museum specimens of English and Scottish Silurian Gastropoda.
Good collections were also sent from Prof. A. H. Worruen in Springfield and Mr S.
A. Minter in Cincinnati together with information on American fossil Gastropoda.
My thanks are also dune for many good elucidations and specimens to Professors
Beyrich and Dames in Berlin, P. T. Creve in Upsala, W. H. Dati in Washington,
H. Douvirte in Paris, J. Harti in Albany, Dr J. G. Hinpe in London, who kindly
undertook to send me casts of some critical species, M. D. Ornterr in Laval for a
fine collection of Devonian fossils, Prof. Frerp. Rozmer in Breslau, Prof. H. Traur-
scHoLp in Moskwa, Lector 8. L. TOrnquist in Lund and Mr J. F. Wurreaves in Ottawa,
Canada. To all these friends I have to express the deep obligation under which |
lie for their kindness to promote my work.

I have been most fortunate to have had the assistance of an excellent draughts-
man, Hr G. Linsevaty, in the execution of the plates. He has not only drawn on
stone all the figures with the exception of the plates XV and XVIII, but also cleaned
and prepared the original specimens before they were figured and he had his full share
in our common interest for the work. His plates speak for themselves and are in no
need of my praise.

PTEROPODA.

The fossil remains of the Upper Silurian Pteropoda of Gotland are by no means
so common nor so characteristic of several beds, as are those of the Gastropoda. As
I do not consider the Tentaculites as Pteropods in consequence of their close affinity
to the fixed Cornulithes and similar, there is only one genus known.

Gen. CONULARIA Minter.

1818 Miter in Sowersy’s Mineral Conchology III. p. 108.

Shell pyramidal, extremely thin, of several strata, each of these homogenous and
transparent, brown or red; near the initial apew the shell is partitioned off by a transverse
diaphragma. Apex often deciduous. Aperture narrow, partially closed by tonguelike prolon-
gations from the corners. Side corners grooved or blunt. Along the middle of each fuce
there runs from the aperture to the apex one or in some species two folds, which project
only a little distance inwardly. In others they are totally wanting or represented by one or
two longitudinal septa placed on the inner side, Surface ornamented by transverse ridges,
smooth or tuberculated, forming an obtuse angle along the median line of the surface with
its apea directed towards the aperture.

The systematic place of this genus and its allies has long been subject to some
discussion and difference of opinion. Among the various opinions on the nature of
Conularia may be annotated that it was ranged with the Cephalopoda by J. Sowrrsy,
Bronn, F. A. Roemer, Bramvirte, G. B. Sowersy, Fiemme, Horninenaus; this may
partly have been occasioned by a false appearance of a siphuncle in the diaphragm,
of which Hatr still speaks as present in his Conularia trentonensis. D’Arcnrac and
VERNEUIL seem to have been the first who considered Conularia as a Pteropod and they
were in this view followed by D’Orpiayy, Morris, De Konrncx, Leonnarp, G. SANDBERGER,
Austin and almost all later naturalists.

Hacker again, in his Morphologie vol. II, page cxtm, denies that the Conularie as
well as the other palwozoie fossils hitherto presumed to be Pteropods belong to that group
of Mollusea and he thinks that no true Pteropods are found in a fossil state anterior to

40 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTRROPODA OF GOTLAND.

the tertiary formations. In still stronger terms than Hacker, Nrumayr in his
paper »Zur Kenntniss der Fauna des untersten Lias in den Nordalpen», Abhandlungen
der K. K. Geologischen Reichsanstalt Bd vi Heft. 5 p. 18, also objects to the affinity
of the Conularim with the Pteropods and he regards them rather as Gastropods nearly
allied to the palwozoic Capulide'). But if we closer consider into this matter, there
appear points of connexion between the Conulariw as palwozoic presumed Pteropoda
and the recent ones, which make it most likely that the questionable fossils really are
Pteropods. First, as to the exterior shape, it seems very difficult to deny that the
paleozoic Hyolithes and several of the recent, as for instance Cleodora australis Rana
resemble each other in a high degree. There are also instances of a pyramidal shape
in the threesided shell of Cleodora lanceolata Rana or Cleodora pyramidata and several
others, Cleodora Deluciana forming an irregular sixsided pyramid thus making an
approach to the foursided shell of Conularia. As to the peculiar transverse ornamen-
tation of the last mentioned genus there are several instances of close resemblance to
what obtains in Conularia levis; as for instance in Cleodora balantium Rane (Balan-
tium Childreni Apams p. p.) and others. Moreover, amongst the now living Pteropoda
there is a sufficiently large amount of widely different forms, more so than in any
other group of the mollusca, that it is almost unnecessary to talk about close correspon-
dence in the exterior shape between species so widely apart in a chronological point
of view as the Silurian or palwozoic and the recent ones.

If not the nature of the shell in Conularia did exclude all thought of their
being Gastropoda allied to the thick-shelled Capulidx, the presence of two peculiar lon=
gitudinal septa on the inner surfaces of the shell of some Conulariw, as for instance
C. bilineata and C. aspersa at once makes such a comparison impossible. Their pre-
sence, on the contrary, is a homology with the recent Pteropoda, amongst which se-
veral of the Cleodore and the Styliole are provided with quite similar septa. These
septa do not occur in all Conularix, but are represented in many by one or more
median, ingoing folds. When more specific forms shall have been found and there is more

1) Lately also Imurtne in his paper: »Die Aptychen als Beweismittel fiir die Dibranchiatennatur der
Ammoniten» in N. Jahrbuch fiir Miner. und Geol. 1881, Bd 1 p. 87 insists that the Conulariz are no Ptero-
pods, but rather to be considered as Cephalopoda, analogous to Endoceras. Of course the thinness of the shell
in most of the Conulariz cannot in itself be held as a very valid argument for their relation to the Pteropods,
but taken in connexion with the characteristic ornamentation of its exterior, with the remarkable longitu-
dinal septa of the interior the aspect of the matter looks otherwise. The argument proferred that since the
Palaeozoic period no Pteropoda have been found before the Tertiary age is of no value. Since the year 1881,
when Inertna published the statement given above, Conularia as well as Hyolithes have been detected in
mesozoie formations and moreover the cireumstance of a fossil form not having been found does not imply
that it never did exist when the strata in question where formed. The same mode of reasoning might some
time ago have been as well applied for instance to Chiton, of which then no specimens were known in the
strata between the paleozoic and latest tertiary. The significance of the size in the paleeozoie and the recent
ones is not to be taxed as high as [uertnG and his followers think. Nor can I find on what grounds Inerina
enumerates Hann and Santer amongst the supporters of his views. The former in his latest works af least
places the Conularie amongst the Pteropoda, as well as Savrer in his posthumous Catalogue. Dana in the
Manual of Geology makes the mistake to delineate the septum of Conularia with a siphonal opening. The
presence of one or more diaphragms in this shell proves quite as little their nature of Cephalopoda as the oeeur-
rence of diaphragms in true Gastropoda or even other groups of animals (Serpule and others, Amplexus
amongst Corals) prove anything for their being Cephalopoda.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wn:o 6. 4]

ample material to work upon, these peculiarities in structure may serve to subdivide
the Conulariz in narrower circumscribed subgenera, as there are concomitant charac-
ters, for instance in the ornamentation.

As to the peculiar diaphragmas, which have been observed in so many Conulariz
near the apex, in some species One, in others several, there is nothing in this feature
that is discordant with the interior structure of the Pteropods, in so many respects
aberrant from the other Mollusca. In the genus Triptera Quoy & Gaymarp (Cuvieria
Rang) ') there is a diaphragma or entire transverse septum near the apex, dividing the
shell into one large chamber, where the animal is lodged, and one smaller, forming
the empty tip and often deciduous, quite as it has been the case with Conularia, where
the apex is gone below the septum. In consequence of what now has been stated, this
genus Conularia may be left amongst the Pteropods, until some positive and decisive
facts have been adduced, causing its removal into another systematic place.

There is, however, a species, C. fecunda, described by Barranpe in his Syst.
Silur. de Bohéme, vol. III p. 38, which has an exceptionally thick and heavy shell, of
many superimposed layers of shelly matter. Such a fossil may throw doubt on the
Pteropodan nature of the whole genus. This species links another curious fossil, Te-
tradium Fr. Scumipr, non Dana’), with the Conularia and makes it probable that it
may stand in some affinity to them, though it not, as has been supposed, is likely to
have been the operculum of some Conularia. It is quite as heavy and compact as C.
fecunda and the anterior aperture has the side corners prolonged into hornlike spines.
As to the interior tubular structure as shown by Scumipr in his fig. 8, and which
according to him also is seen in Conularia, it may probably be derived from some
parasitic fungus, as so often is the case and also may be seen further down in Tryblidium.
In the specimens of Conularia, which I have examined, I have not hitherto found any-
thing at all analogous.

In Sweden the Conulariz make their first appearance in the Upper gray Ortho-
ceratite limestone of the isle of Oland with a species, which is scarcely discernible from
the later, which occur in the Chasmops limestone of Boda on Oland, in the younger
Retiolites shale of Borenshult. in Ostergdtland and, as it now seems likely, also in the
Upper Silurian strata of Gotland under the name of C. cancellata Sanpp.

Of this genus there are found in Gotland five species of which three are compa-
ratively common, but of the two others only one specimen to each is known.

These species may be arranged in the following groups.

* Ornamental ribs thick with closely set tubercles.
1. C. cancellata SANDBERGER.
2. C. monile n.

') Description de deux genres nouveaux appartenant & la classe des Ptéropodes, Ann. Sc. Nat. Tome XII
39
p- 324.
2) Scumtp? Miscellanea Silurica IT. in Mém. de Acad. Se. de St. Petersbourg VII Ser. Tome XXI. N:o
11 p. 42.
K. Sv. Vet. Akad. Handl. Bd. 19. Nio 6. 6

42 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

** Ornamental ribs smooth.
3. C. levis n.
*** Ornamental ribs extremely narrow and close with microscopically minute
tuberebles. Two median septa along the faces.
4. C. ilineata n.
5. C. aspersa n.

1. Conularia cancellata Sanpprrcer.

Pl. I fig. 1—8.
Conularia quadrisulcata. 1824. Dauman (not Sow.) Vet. Akad. Handl. 374, tab. IV f. 3.
» > 1828. Husincer Anteckningar hft. 4; 72, 236.
» » 1829. Ip. Tableau des pétrif., 8.
» » IfSBWls | Woy, » » Kd. 2, 6.
» » 1837. [p. Lethaa Suecica, 30, pl. X f. 5.
» » 1839. Sowersy in Morcnison Silurian Syst. IJ, 626, pl. XII f. 22.
» » 1840. Hts. Anteckn. VII, 70.
C. Sowerbii. 1843. Morris Catal. Brit. Foss. 168.
» 1845. VeErnevi in Murcuts., Vern. & Knyseru. Russia vol. II, 348, pl. 24 fig.
5 a—b.
» 1854. Morris Catal. Brit. Foss. 2d Ed. 232.
» 1855. Sautrpr Appendix to Supewicks British Palaozoie Fossils, VI.
» 1858. Fr. Scamipr Untersuch. Silurform. Estlands, 209.
» 1859. Saurer Siluria 3d Ed., 550, pl. 25 f. 10.
» 1860. ExcuwaLp Letheea rossica vol. I, part II, 1052.
» 1867. Eruertper in Siluria 4:th Ed., 534.
» 1867. Lrypstrom Nomina fossilium Gotlandia, 23.
» 1873. Saurer Catal. Cambridge Sil. Fossils, 67, 153, 171, 185.
C. cancellata 1847. Sanppercer Neues Jahrb. f. Min. & Geol., 20 (= C. quadrisuleata Sil. Syst.)
» 1848. Bronn Nomenclator, 327. :
» 1855. Mac Coy in Sepewrck’s Brit. Paleoz. Rocks, 287.
» 1867. Erupringe in Siluria 4:th Ed., 534.
» 1869. Herpennain Graptolithfiihrende Geschiebe der norddeutschen Ebene. Zeitschr.
d. Deutsch. geol. Ges., 162.
C. curta. 1847. Sanppercer N. Jahrb., 14 (= C. quadrisuleata Dauman, His.)
» 1848. Bronn Nomenclator, 327.
C. erenijugata. 1847. Sanpprreer N. Jahrb., 19 (= C. Sowerbyi Vern. and Morris).
» 1848. Bronn Nomenclator, 327.
C. proteica 1854. Barranpe Neues Jahrb. f. Min. & Geol., 2.
» 1865. Ib. Défense des Colon. III, 41.
» 1867. Ip. Syst. Sil. Boh. III, 48, pl. 5—6.

Shell conical, quadrilateral, but so much compressed from the sides, that it looks
almost bilateral, two of the four faces being on the same side, divided through a deep
furrow, which runs exactly along the median line of that side from the aperture to
the apex. The two other dividing furrows are situated at the exterior edges of the
shell. A transverse section near the apex is in well preserved specimens rhomboidal,
further down towards the apex elliptical or resembling the number 8, being deeply
indented along the median axis of the sides by the lateral grooves. The four sides
are each, near the aperture, prolonged into a broad tonguelike lobe, through which the
aperture is much narrowed, as these four lobes nearly meet and only have a narrow

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. Nn:o 6. 43

opening between them. The shell is exceedingly thin and consequently wrinkled and
much crushed, but still retaining the delicate details of its fine ornamentation. It
consists of two layers, the inner one being thinner and of a paler colour. The colour
is pale yellow and in some instances brownish. The transverse ridges of crenulations
which adorn the exterior surface are five on a length of 2 millimeters, and bent in an
obtuse angle upwards, towards the median axis of the side, in some the inclination
being so feeble, that the ridge nearly has the form of a straight line. The longitudi-
nal axis is not always exactly in the midst of the side, being in some specimens si-
tuated a little nearer the outer edge and thus dividing the face in two unequal moie-
ties. The furrows between these ridges are nearly twice as large as them. The orna-
mentation of the ridges and the furrows varies with the distance from the apex. Near
this the ridges are smooth without any indentations, but they are higher up first beaded
by blunt tubercles, which from the middle of the shell take the shape of more or
less blunt spines, as is shown on a magnified scale in figures 1—3. Each spine con-
tinues downward into the furrows in a sort of handlelike prolongation, obliquely slan-
ting towards the median axis of the side and between these handles there are oval,
excavated pits. The spines of the adjacent ridges, as seen in figures 1—2, are arran-
ged in alternating position; every second row having its spines above each other and
placed opposite to the interstices of the two nearest, below and above. In a longi-
tudinal section therefore, as figure 3, there are seen alternating long and short spiny
projections, the long ones being real spines, the shorter again the next ridge, cut
through in a spot between two of its spines. The spines are interiorly hollow towards
their base and consequently, when the point is broken off, as often happens, an an-
nular opening is formed. The septum, which is situated near the deciduous apex and
closes the shell, when the apex is gone, is smooth and glossy, of the same pale yellow
colour as the shell and covered by a few irregularly concentric lines.

Dimensions. Height 44 millim., breadth of a face near the aperture 16 millim.;
fragment of another face 23 millim.

Occurrence. It has been found in the oldest shale beds (a) in Fard at Kyrkviken,
and other localities, in the lowest beds at Hallshuk, on the shore south of Gnisvard,
and at Djupvik in Eksta. It has also been collected in the overlying limestone of Lansa
in Faré, Snickgirdet and Vattenfallet near Wisby. It is most common in Faré, from
where the State Museum possesses nearly 30 specimens.

This species has a wide distribution in time and space. I cannot distinguish the
specimens occurring in the Upper gray Orthoceratite limestone of Oland, in the Chas-
mops limestone and in the Retiolites shale at Borenshult from the Upper Silurian spe-
cies‘). There are only small variations depending on the state of preservation and
others of mere subordinary value. Nor can I find any specific distinction between the
English and Bohemian specimens, which I have seen, and the Swedish ones. The beau-
tiful plates of Barranpe moreover are decisive. It is unaccountable how this spe-
cies has been so often named as ©. Sowerbyi De France. In vain I have searched in

') For an elucidation of the various groups of the Swedish Silurian formation, mentioned here and elsewhere
in this memoir, see Appendix A.

44 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

the »Dictionnaire des Sc. Nat.» where it is stated that De France has named it. I
only find in vol. 32 p. 193, article »Mollusques», which is entirely written by Bratn-
vitLE, »Conul. Sowerbii Durr. Dict. des Se. nat., Fossiles», but on turning to that
article nothing at all is found concerning Conularia. The accompanying figures are
exact copies from the Mineral Conchology of Sowrrsy of his C. quadrisulcata, which
no doubt is a Carboniferous species. C. Sowerbyi is consequently a synonym of this
species and not of the Silurian one. When thus neither the name C. quadrisulcata
nor ©. Sowerbyi can be employed, we are obliged to adopt the next in chronological
order and then we have three described, all at the same time, by SanpBerGer. But
these three species, cited above, are only synonyms. Of these I have chosen C. can-

cellata as being given to the species of the »Silurian System». C. curta has the prio-
rity but is very unappropriate and seems to be founded on a spurious specimen. As
Sauter, App. Brit. Pal. Fossils p. VI, remarks, the Devonian C. Gerolsteiniensis pb’ ARCH.
& VmrN. is so nearly related to this, that it may be considered as a variety.

Amongst the American Conulariw, described by Haun, C. trentonensis, Pal. N.
York vol. 1 p. 222, possibly is the same as Con. cancellata. See also Excawaup Leth.
ross. 1 p. 1057 on Con. trentonensis.

2. Conularia monile n.
1) Ei a 14s el

Shell formed as a regular, foursided, narrow and elongated pyramid. The trans-
verse section of the aperture is a regular quadrate having each of its corners inflected
by a groove. The shell substance is comparatively thicker in this than in the other
species and consists of an exterior, darkly coloured stratum, which is thicker than the
interior thin and pale one. The ornamenting, transverse ridges, of which eight are
contained within a length of 2 millim., are bent in an obtuse angle, larger than in any
ether Swedish species. Its apex is situated exactly on the median axis of the face.
The interstitial furrows are quite as large as the ridges or alittle narrower. The ridges
near the apex of the shell are smooth or nearly so, higher up they are closely studded
by narrow, clongated, laterally compressed or sharply edged lamellw, ending in an
accuminated point upwards and placed in oblique rows on the ridges, their lower apex
turned against the median axis. The intervening furrows are quite smooth. On the
nucleus, where the shell has been destroyed, there is an impression of a median ridge,
nearly one millim. broad. It runs on the inside of the shell along the median axis of
each face, thus corresponding to the line which may be thought combining all the
apices of the angular ridges on the outside. It forms consequently a blunt, longitudinal
ridge on the interior wall of the shell. Height 24 millim., diameter at the aperture 14
millim., diameter across the lower broken end 5 millim., diagonal line at the upper
aperture 14 millim., diagonal at the lower end 6 millim. Found only once in the
limestone strata b near Wisby.

qo

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. 4!

3. Conularia levis n.

Pl. I figs 13—16.

Shell regularly pyramidal, foursided, elongated and narrow. ‘Transverse section
of the aperture quadrate, the four faces being of the same size or nearly so. Owing
to the deep furrow along the middle of each face the outline of the transverse sec-
tion becomes nearly quadrilobate. The shell substance is thicker than in anyone
of the other species. It is glossy, brownish yellow and an exterior thicker stratum
covers the interior one, which is paler and thinner. It is transversally wrinkled by
irregular folds, curved upwards in a gentle arch, sometimes large and sometimes narrow.
In some specimens there are only faint traces of such wrinkles and the shell is almost
smooth, even for long distances. The wrinkles are often not continuous across the
deep, longitudinal furrow, which divides each face into two halves, but are in pairs,
which do not always exactly correspond with each other, the opposite ones not being
placed on the same level. Besides these wrinkles there is no other ornamentation
excepting smaller and finer strix parallel to the wrinkles. The longitudinal median
furrow is, as already mentioned, uncommonly deep, but there are no vestiges of any
septum, connected with it on the inside as in some other species. The grooves in the
corners are entirely smooth and the transverse folds cease ere they reach them.

Height of the most complete specimen 27 millim., diameter at aperture 12 millim.,
diagonale 14 millim., diam. of the broken apex 4 millim. A fragmentary specimen from
a detached block of the white limestone of the stratum c¢ measures 35 millim. in
length, 15 millim. in breadth.

It has been found in several specimens in Faré, in the limestone of Bara hill,
near Wisby in the middle limestone stratum, 6, and in the passage bed with Ptery-
gotus between the strata b and ¢ and lastly in the limestone with Rhizophyllum near
the church of Lau.

This beautiful species, so dissimilar to the other Gotland species is nearly related
to the English Lower Silurian (Caradoc) C. levigata Sarrrr Mem. Geol. Survey, III,
354, which, however, is rhomboidal in its section. The Bohemian ©. pyramidata Hor-
NINGHAUS (BarranpE. Syst. Sil. Boh. vol. IH, p. 50, pl. 2 fig. 1—6) is much larger,
but of the same tapering, straight pyramidal form and has the wrinkles unequal. A
much later species, the Con. missourensis SwALLow from the Carboniferous formation,
comes also very near to C. levis.

4. Conularia bilineata n.
Pl. I figs 4—8.

Shell regularly foursided, pyramidal, but short in proportion to its broad basis.
Two of the sides are larger than the others and the opposite sides are of the same

46 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

size. The section of the aperture is rectangular with the corners rounded and a little
bent in by the grooves. The substance of the shell is extremely thin, quite as much
as in the following species, and seems to consist only of a single stratum, which has a
chestnut brown colour. The outer surface is very finely striated by arched, almost
microscopically minute, transverse lines. They form a gentle curve, highest at the
median, longitudinal axis of the face and lowest at the corners, where they again are
slightly bent upwards. They are so crowded as to be about 26 within a length of 2
millim. from the midst of the shell and upwards (fig. 7), but lower down, near the
apex, they are more apart (fig. 6), that the interstitial furrows there are nearly
thrice as large as the elevated lines. When these transverse lines are examined with
high magnifying powers they are seen to be covered with closely set, elongated, oval
tubercles (fig. 8), protracted into acuminated apices above and below. The interstitial
furrows are quite smooth and glossy. What is most remarkable in this species is the
presence of two longitudinal septa on the interior surface of each face. They are seen
on the outside ‘through the transparent shell, as two black longitudinal lines, which
continue slightly diverging from each other, being one millim. distant near the apex
aud 3 millim. near the aperture, always on both sides of the median axis of the face.
They project a little inward in the cavity of the shell, as seen in fig. 5 and they
correspond evidently with the single ridge of which there is a faint trace in Conularia
monile and are probably also homologous to the longitudinal septum of the recent
Styliola. — Height 40 millim., breadth at aperture 32 millim., shorter diam. of same
28 millim., diagonal 35 millim., breadth at apex 5 millim. Hitherto only one specimen
has been found in the shale beds at Lansa in Faro.

5. Conularia aspersa n.
Pl. VII figs 1—3; pl. XIX fig. 1.

Shell tapering, conical, probably regularly pyramidal, but this cannot be ascer-
tained as the extreme thinness of its substance has caused that it has been preserved
only in compressed and wrinkled specimens and consequently the outlines of only one
face is laid in view, when the soft, marly limestone in which it is enclosed, is split open.
Although the thin shell is bent in many creases and wrinkles, its delicately ornamented
surface is beautifully clear and distinct. Along the median axis of each face there
run two straight, nearly parallel septa, visible on the outside as dark narrow lines.
There are absolutely no ingoing folds on the exterior surface, where they are situated,
what is so common in other species except the preceding one. They slightly deviate
in their course upwards and are nearly two millimeters apart near the aperture. The
transverse rows of the ornamental tubercles are more closely set than in the preceding,
nearly related species. They number as many as 14 along a longitudinal line of one
millim. Being so close, they with their tiny tubercles give the surface a chagreened
appearance. The tubercles are nearly circular knobs with the interstices confusedly
streaky. The colour is dark brown or chestnut.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. n:0 6. 47

Length 51 millim., breadth near aperture 25 millim.

Several specimens have been found in the Pterygotus beds between the middle
and superior limestones at Vattenfallet near Wisby.

This and the preceding species form a division of their own with ty
each face and the microscopically minute ornamentation.
Bohemian C. munita is somewhat resembling.

vo septa on
Among coéyal species the

GASTROPODA.

Fam. I CHITONIDAL Guinpina.

Gen. CHELODES Davinson & Kuna.

1867 Chiton BArraNnveE Syst. Sil. de Bohéme vol. III p. 175.
1874 Chelodes Davips. & K. Qu. Journ. Geol. Soc. p. 167.

Valves oblong, generally longer than broad; no lamina. of insertiun nor sutural lamine;
apical area of the inside highly developed.

It was only with some hesitation that I placed these curious fossils, of which
there are at least two species, amongst the Gastropoda as a genus of the Chitonide.
Led astray by some superficial points of resemblance I at first mistook them for one
of the aberrant group of the Brachiopoda, the Trimerellidw, and accordingly sent the
material I then could dispose of to Mr Davipson, when he jointly with Prof. Kine
was working out a Monograph on that group. They described the only form which
was then known as Chelodes Bergmani’), stating that it was none of the Trimerellide,
but that it rather should be considered as belonging »to a section of the Coelenterates,
represented by Calceola and Goniophyllum». The authors do not expressly say whether
it should be regarded as the polyparium itself or as the operculum, but it seems most
likely, that they have thought the last to be the case. There is, however, no coral in
the Silurian formation of Gotland that possibly could have been provided with an
operculum of so peculiar a shape. The form of the calyx at its aperture is generally
circular or polyédric, never assuming such an outline as Chelodes shows.

There is not the least doubt that these questionable fossils belong to the same
genus as those which Barranpe in the third volume of his grand work »Systeme Si-
lurien de la Bohéme p. 175, pl. 16 fig. 19—28 has figured and named Chiton Bohe-
micus. Besides this there are several other palwozoic fossils of almost the same shape,
which have also been referred to the genus Chiton. Closely related to the Silurian ones
are some detached plates, which Ktrxsy has described and figured with some hesitation

1) Qu. Journal Geol. Soe. 1874, p. 167.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 49

as belonging to his Chiton? cordatus'). It may now be questioned whether all these
similar fossils truly be remains of Chitons or not. What most strongly militated against
their belonging to that family of Gastropoda was the circumstance that they are all
entirely wanting the characteristic two apophyses or sutural lamine which are si-
tuated in the anterior margin of the plate and believed to be present in all recent
Chitons and in almost all the paleozoic ones described by pr Konincx, RycKnort,
Kirksy, Batty, SALTER and SanpBercer. In the Gotland specimens and, as far as one
is able to judge from the figures and descriptions of BArrANDr and Kirxsy, also in the
Bohemian and the supposed median plates of Chiton? cordatus there is not the least
trace of there ever having been any apophyses. Nor does the elongate shape of the
plates, generally longer than broad or often of the same height as breadth, agree with
the transverse form of the plates so common amongst the recent and fossil Chitons.
As Kirxsy remarks (Qu. Journ. Geol. Soc. vol. 15 p. 617) there is, however, one of
the recent Chitons, Ch. hastatus Sow.”), in which the intermediate plates bear a close
resemblance to the palzeozoic ones. Moreover, in the recent genus Leptochiton Car-
PENTER, now confined to the arctic and temperate seas, there is an approach to the
plates in the paleozoic Chitonide as they are without any lamine of insertion, but
mostly provided with sutural lamine *).

On the inside of the plates of Chelodes there is also a feature, which is by far
not so prominent in Chiton. At the pointed posterior end of the inside is a large
triangular area, covered by transverse, parallel, curved lines of growth. In Chelodes Berg-
mani, for instance, it occupies a little more than half the length of the plate. A similar,
I should be inclined to say a homologous, area is seen on quite the corresponding
place in the more recent Chitons, although it there in most of the transverse plates is
restricted to a narrow stripe. In others again it occupies nearly a third of the total
length of the plate. It seems hardly to have received all the attention it deserves,
even not by such an accurate monographist as Mippenporrr. It is evidently with this
part of the interior surface that the plates posteriorly overlap each other and which
consequently is not covered by the tissues of the animal. By the continued growth of
the plate this area must be enlarged, when the soft tissues retire and a new line of
growth is added to it. The mode of formation of the interior apical area of Chelodes
has in all probability been the same, although it is enormously more developed than
in most Chitons, perhaps only having its counterpart in Chit. hastatus.

Excepting the Chitons there are no other shell-covered animals with which Che-
lodes may be compared than the Lepadide. Amongst the numerous valves, which
form the integument of the Lepadidw there are only two or three regularly formed,
whilst all the others are more or less oblique. There is indeed some similarity be-

1) »On the permian Chitonidee». Qu. Journ. Geol. Soc. vol. 15 (1859) p. 616, pl. 16 figs. 25—26 and
also in the Geological Magazine vol. 4, p. 541, pl. 16 figs 11a—11b, where Kirksey and J. Youne describe
the Chitons from the Carboniferous strata of Yorkshire and Western Scotland.

*) Reeve Conchologia Tconica, vol. IV, pl. 25 fig. 166 and plate showing details of sculpture, enlarged
fiz. 166.

3) Dati, H. W., the results of the recent investigations into the Natural Hist. of the Chitonidse. Smith-
sonian Miscellaneous Collection, vol. XX, p. 193.

K. Sy. Vet.-Akad. Handl. Bd. 19. N:o 6. 7

50 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

tween the valve which Darwin calls rostrum‘) and Chelodes. This is evident if we for
instance compare the rostra of the genus Scalpellum Darwin, Lepadide pl. VI, figs.
6a, 7a, 8a, and amongst the fossil ones Pollicipes Nilssoni Darwin, Fossil Lepadide,
Pl. HI fig. 11 d, and it seems indeed very likely that some of them really have been
mistaken for Chitons and figured by Kirksey in the paper cited above. The general
outline is almost the same and on the inside there is also an apical area, composed
of concentric lines of growth. This area seems, however, not to have been formed in
the same manner. In the Chitonide and consequently also in Chelodes its superior
or youngest margin is always elevated above the upper or distal part of the interior
face, as is also the whole area; in the Lepadide again the area is generally lower than
the other surface. If Chelodes were a Cirrhipedian, it would be in the highest degree
strange if only one valve, the regularly formed rostrum, had been preserved and not
a single one of the others, which are at least six in number, but in some species much
above hundred.

A quite different conjecture as to the nature of this fossil is given by Inprine in
his paper on Aptychus*). He there, page 70, says »that it is at least to me highly
probable that what Barranpge has described as the plates of Chitons, in the reality are
Aptychs of Silurian dibranchiate Cephalopoda». He continues, that if they are de-
rived from Chitons, they can be interpretated only as the final plates and it is strange
if only these were preserved of all eight plates. Against this is to be remarked first
that the plates figured both by Barranpe and by me are not all identical, but of diffe-
rent orders, secondly that in the recent Chiton hastatus the plates are quite as acu-
minate and elongated relatively as in the Silurian ones. Moreover, the conformation
of the inside, which was unknown to Inertmnac, removes these fossils from Aptychus.
As to the microscopical structure, on which Inertne justly lays so much stress, there
is unfortunately no guidance to be had, as the chief mass of the very thick plates of
Chelodes has been converted into clear, transparent calcareous spar.

What, for the rest, adduces me to range Chelodes, at least provisionally, with the
Chitonide, notwithstanding all that has been said to prove its similarity with other groups,
is the circumstance that the exterior ornamentation of the plates is in complete accordance
with that of the Chitonide. Moreover, there is at least one ascertained instance, in which
valves of the palwozoic Chitons, also wanting apophyses, have been found in their o77-
ginal position. In the specimen of Chiton Grayanus, drawn on plate I fig. 1 of pr Ko-
NINCK’S »Deux especes siluriennes de Chiton», there are five valves in juxtaposition.

But if we now are to conclude that Chelodes is one of the Chitonids, it shows
so great differences from the others, that it cannot belong to the genus Chiton pro-
per, where Barranpe placed it, but must form a genus of its own. Of all the palo-
zoic subgenera, no less than 13 created within the last twenty years,there is one, Sag-
maplaxus Oratert’), which so nearly coincides with Chelodes that both may be con-

') Darwin Monograph of Cirrhipedia. Lepadide. Ray Soe.

*) Die Aptychen als Beweismittel fiir die Dibranchiatennatur der Ammoniten. N. Jahrb. fiir Mineralogie
ete. 1881, 1 Bd Heft 1, p. 44.

3) Documents pour servir a l'étude des Faunes dévoniennes dans Vouest de France in Mém, Soc. Géol.
de France 3:me Sér. tome II, p. 15, pl. II, fig. 3, 3 a, 3 b.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. 51

sidered as ranging very near to each other. The author says expressly »il n’existe
pas dapophyses dinsertion a la partie antéricure». Its area is also described as large
as that in Chelodes. Sagmaplaxus occurs in the »Dévonien inféricur de la Sarthe»
and can indeed be said to be a more developed descendant of Chelodes. It is by
far larger and longer than the latter.

1. Chelodes Bergmani Davinson & Kuve.
Pl. IL figs 1—8.
Chelodes Bergmani 1874 Dav. & K. On the Trimerellide ete. Qu. Journ. Geol. Soc. vol. XXX, p. 167, pl.
18, fig. 14—14 a—d.

Plates of conical outline, anterior margin straight or slightly emarginated or even
convex, lateral margins continuing nearly parallel a little below the middle, then sud-
denly converging to form the acute posterior apex. Surface somewhat weathered,
shows faint traces of punctuate ornamentation on the transverse lines of growth. These
are most conspicuous near the lateral margins and they are parallel with the anterior
margin of the plate. In a transverse section the plate has the shape of a crescent,
being evenly arched, without any sinuosity on the back. The inside of the plate is
divided in two parts, of which the posterior, occupying exactly half the total length,
consists of the slightly excavated apical area. The transverse, gently arched lines of
growth resemble narrow, low ridges or callosities, they are very numerous and dense
and the whole area is raised a little above the anterior part of the valve. This is
longitudinally divided in two portions by a well marked sinus, towards which the sides
gently slope. This anterior surface is smooth, showing only indistinct traces of mus-
cular impressions towards the lateral margins, being near the sinus coarsely and lon-
gitudinally wrinkled. All around the lateral margins of the interior surface there runs
an elevated narrow border, formed, as it were, by the bending over of the exterior
shell stratum. The plate is at its thickest in the median part and thins off towards
the apex.

Height 20 millim., breadth 13 millim.; thickness in the middle 5 millim., at the
apex 1,5 millim.

Two specimens have been found in the uppermost limestone of Klinteberg and
a single plate in the oolite quarry near Gannvik in Grdtlingbo.

2. Chelodes Gotlandicus n.
Pl. I figs. 9—27.

Plates cordate, with anterior margin deeply emarginated, posterior apex acumi-
nated, lateral lines, combining anterior margin and apex, gently curved. The plates
are generally longer than broad, much varying, as may be seen by the dimensions given
below, some even being transverse. They have consequently been placed in different
positions of the series. They are much more elevated along the median line of the
back, than in the former species and the sides are more sloping. In a transverse sec-

52 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

tion (fie. 23) they form a nearly right angle. The surface is deeply grooved by
transverse ridges, coinciding with the lines of growth and separated from each
other through narrow interstices. They exactly follow the same direction .as the out-
lines of the anterior margin, being bent backwards at the lateral margins, then for-
wards and on the middle of the back again backwards, thus forming a sigmoid line.
They are most conspicuous near the margins. ‘There is a central area formed by two
lateral, longitudinal grooves, which run nearer to the lateral margin than to the cen-
tral ridge and converge towards the posterior apex. These grooves are conspicuous
in a few specimens, being effaced by corrosion in the others. The exterior sur-
face is moreover ornamented by numerous, minute wartlets, which are closely set
in regular, transverse rows (fig. 15). On the inside of the valves there is seen, first
the posterior apical area, which is of highly varying width, in some occupying nearly
half the length of the surface, in others only a fourth (fig. 25) just as in a recent
Chiton, of which a figure is given on plate II, fig. 28. Owing to the state of con-
servation of the specimens, the lines of growth are more obscure than in the former
species. The whole inside is longitudinally divided into two halves by a deep sinus;
the sides being more scooped out at the apical area, the side parts of the anterior
surface being more tumid. No traces of muscular impressions are visible.

Specimen A height 18 millim., breadth 14 millim., B h. 11 millim., br. 12 millim.,
Ch. 18 millim., br. 11 millim. In a specimen of 14 millim. in length, the greatest
thickness of the plate is 3 millim.

This species is more common than the preceding and has been found in several
specimens at Groétlingbo in the oolite quarry near Gannviken, in the sandstone of Burs-
vik, in the oolite near Rone and also in several detached plates in the limestone above
»>Kalens qvarn» near Wisby.

Fam. II. PATELLIDA p’Orsieny.

Gen. TRYBLIDIUM Linpstro6m.

Syn. 1836. Metoptoma Puiuuirs p. p. Geol. of Yorkshire pt. 2 p. 223.

1880. Tryblidium Lom apud Ancunin & Linpsrrom Fragmenta Silurica p. 15.

Shell patelliform, obovate, anteriorly acuminate, posteriorly enlarged, forming a very
low cone. Apex anterior, nearly marginal, with only very little area beneath. Margin of
the ovate aperture arched, so that the animal, when fixed, was not entirely hidden beneath
its shell. Muscular scars in six, disconnected pairs, arranged in an oblong cirele, open or
nearly so towards the front part of the shell. Intimate structure of the shell somewhat
resembling that of the recent Patella, being composed of thin strata of polygonous cells.

This new genus, which I at first described in ANGELINS and my work »Fragmenta
Siluricay p. 15, had by some paleontologists long been considered as belonging to the

Bl aes

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 53

brachiopoda, though they did not publish their opinion. When we, however, compare
one of the species, Tr. unguis, with recent forms of the genus Patella, it is quite evi-
dent that it both on exterior and interior grounds should be numbered amongst the
Gastropoda and especially in the family of the Patellide. In plate I, fig. 38 there is
delineated a recent species of the subgenus Nacella Apams from Foua, which as to its
exterior shape, sculpture and colouring as nearly as possible resembles Tr. unguis fig.
33. And again if we turn to the interior muscular scars and compare figures 30 and
37 on the same plate with Patella cochlear L. fig. 32, there is, if we except some
differences in the details, the same disposition of the six or seven pairs of those im-
pressions. The species of this Silurian genus Tryblidium, and especially, such a form
as Tr. unguis may then be added to the so called persistent types of Huxiey, which
as the Lingule and Cranie amongst the Brachiopoda and Calostylis amongst the Co-
rals have continued till our time with small or insignificant modifications in their
structure. It is intermediate between the recent genera Olana and Nacella.

In the Silurian species the scars are disconnected and deep, the more so in
the oldest form, »Patella» antiquissima, from the Swedish Lower Silurian, being ap-
proached, though separated, in the Upper Silurian species. In the recent Patelle,
the scars are in most species nearly connected, though it, especially on their inner
margin, is possible to discern how they have been independent. This is the more evi-
dent, when we turn to the animal itself, where muscular pairs of variable number in
the same species, from six to nine, are distinctly detached and free at least partially
and do not form a continuous ring as in the Scutellide. As in Tryblidium the foremost
pair is also the largest with the recent Patelle, but there is the great distinction that
both these last muscles of the living Patelle are united through a narrow stripe of
muscular tissue, forming an arched curve, also visible as a scar on the shell, whereas
in Tryblidium the narrow stripes which are emitted from the large, foremost scars do
not unite, but leave an open space between them. Characteristic to the foremost pair
in Tryblidium is also the large appendiculated scar on their inner margin, of a
peculiar reticulation, described more in detail below in Trybl. unguis. The change
in this respect from the older to the recent Patellwe has thus consisted in the concen-
tration of the once detached and entirely independent muscular scars.

In the »Paleozoic Fossils of Canada» Biniines has described a species of Metop-
toma, M. Hyrie, p. 87, fig. 79, which comes near to Tryblidium unguis as far as may
be judged by the exterior appearance. It is evident that Brrzines in the cited work
has enclosed within that genus too many species which do not show the characters
given by its author Puixuies in »Geology of Yorkshire» pt. 2, p. 223 and that conse-
quently only some of them are true Metoptomex. Merk and Wortuen’) make the ade-
quate remark, that later authors have given to that genus a greater extension than PHiL-
Lirs intended. The new genus which I have proposed, differs from Metoptoma in wan-
ting the broad truncated area below the apex. The muscular scars also differentiate
these two genera, as there in Metoptoma, for inst. M. pileus Puituips, according to De

1) Proc. Aead. Nat. Se. Philadelphia, 1866, p. 266.

54 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Koninck in Descript. Anim. foss. de Belgique Supplem., p. 685, pl. 58, fig. 1, exists
a coherent muscular scar, horse shoe shaped, with the apex of the shell towards its
hind side’), whereas in Tryblidium there are six pairs of detached scars, and the apex
anterior.

From the uppermost beds of the Lower Silurian rocks of Esthonia, at Borkholm,
I have seen specimens of two species belonging to this genus,’ true forerunners to the
two Upper Silurian ones; of these one can scarcely be distinguished from Tr. unguis,
the other again very closely resembles Tr. reticulatum. From Raikiill in Esthonia, in
FRIEDRICH Scumipts stratum G 3, at the base of his Upper Silurian there occurs also
a third species, allied to Tr. unguis, but regularly, transversally imbricated by equi-
distant lines of growth, and of an almost elliptical outline.

Mr I. F. Wurrgaves, of the Geol. Survey of Canada, has recently”) described a
»Tryblidium Canadense» from the Guelph formation of Canada. In respect to its ex-
terior shape it might well be united with the Tryblidia, though it is more elevated,
but the figures of pl. V, f. 1 & la show a narrow, continuous ring of muscular im-
pression, quite unlike what prevails in the other Tryblidia and, moreover, there are
below the apex two oval depressions different from anything seen in the Tryblidia. Till
these points are cleared up, the Canadian species can only with hesitation be placed in
that genus. Whuuireaves also thinks that Metoptoma Niobe, M. Nycteis, M. Eubule, M.
Erato and M. Hyrie Binuies are typical species of Tryblidium. This can, however, not
be finally settled, before the muscular impressions shall have been discovered.

Metoptoma Erato Brinures ‘Paleozoic Fossils of Canada» vol. 1 p. 39, is near to
Tr. unguis, but probably identical with the Esthonian species, as it is derived from the
Lower Silurian stratum called »Black River Limestone». Nearly allied to this genus is
also the Lower Silurian »Patella antiquissima» described by Hu1stycer and formerly
found at Borenshult in the Retiolites shale. In outward shape it reminds of Paleac-
mxa Hatz, and it is also like several of the Metoptomex, but the six pairs of most
beautifully preserved muscular scars place it near Tryblidium.

As to the first appearance of this group within the paleozoic era InpRING says
in his »Anatomie und Phylogenie der Mollusken», p. 82, »ist doch so viel sicher, dass
die paleozoischen Patelloideen Tecturiden waren», and further: »in der Primordialfauna
sind schon die Tecturiden und Lepetiden vertreten», and he seems to confound the
Patellide with the Patelloidex, as he numbers Patella vulgata amongst them, nor does
he anywhere mention the occurrence of the Patellide. But through the occurrence of
the Tryblidia and other kindred genera, already present in the Lower Silurian we find, that
the Patellida were also represented by numerous, well developed shells and consequently
that both families, the Tecturide and Patellida coexisted.

') Nicuoison again in his Handbook of Paleontology II p. 34 says that in Metoptoma »the muscular sears
consist of a number of disconnected cavities».
*) Geol. & Natural History Survey of Canada. Paleozoic Fossils, vol. Ill, pt 1, pp. 30—31, 1884.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0o 6. 5

fu |

1. Tryblidium reticulatum Linpsrr.
Pl. I figs. 25—31, pl. Ill figs. 15.

Tr. reticulatum 1880. Linpst. in Ancerin & Linpsrroém Fragmenta Silurica p. 15, tab. X, fig. 7—16,tab. XIX,
fig. 9—12.

Shell much depressed and generally more flat than the following. Apex obtuse,
erect, with a narrow, area-like zone between itself and the margin of the shell. Out-
line of the shell, when seen from above obovate, anteriorly acuminate, enlarged towards
the posterior margin. The surface is ornamented by a series of thick, transverse and
concentric, elevated laminw, which in the anterior, third part of the shell intercross
with each other and thus form an elegant network, but in the other two thirds of the
surface are parallel, wavy, thin at the edges, thickened towards their base, and evi-
dently formed by the margins of the shell bending upwards. In the oldest part, corre-
sponding to the shell of the young, the callous, transverse lines are very fine and
crowded. Around the apex there is almost always an oblong space more or less ex-
foliated. The exterior stratum of the shell is there worn away, making the interior yellow
stratum alone visible. Sometimes there is the false appearance as of a foramen, which
has been filled up again, but this is evidently owing to imperfect corrosion.

The aperture is obovate, the margins very thick, forming a callous border. When
seen from the side the line formed by the margin is an elongated curve or an arch,
highest along the middle of the shell and sinking towards both ends. The foot of the
animal, when resting on its basis, must then have been left uncovered along the sides.
On the interior surface, which is very smooth and almost glossy, there is a dark co-
loured circle, formed by six pairs of muscular scars, of which the foremost are the
largest and nearly connected by narrow appendages, like stripes, almost as in the recent
Olana cochlear. See plate I figs. 30, 32. Each separate scar is more elevated towards
its curved interior margin and at its exterior margin they are lobate or lacerated. The
foremost pair is the largest, composed as it were, of several parts, of which the inner-
most is elongated, elliptical, the exterior one irregularly square; from its anterior
margin there projects, from each pair, a narrow stripe; these stripes do not unite,
but leave between them a short space. The central surface, enclosed by the muscular
ring, is excavated in shallow, arched depressions all along the interior border of the
sears, being situated in the interspaces between these. The scars themselves are
separated through narrow projections from the enclosed surface. Sometimes there are
large concentric callosities') due to the irregular growth of the margin, which cross
the central field.

There are specimens still retaining traces of the original colour of the shell in
dark longitudinal stripes, distinctly conspicuous on the other dull surface (f. 29).

As to its intimate structure the shell consists of two distinct strata, of which the
exterior one easily peels off and the interior, in specimens from certain localities, is
the only one left on the nucleus of the shell. The exterior stratum is thick, attaining
as much as 5 millimeters in some parts. It consists of very thin laminw which seem

1) Fragm. Silur. pl. XIX fig. 9.

56 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

to be composed of prismatic cells. Near the apex this outer stratum is entirely pris-
matic. It is generally of a whitish hue, contrasting with the interior one, which is
yellow. The later is very thin, consisting of minute lamelle of an apparently prismatic
structure. A singularity in structure is that figured on pl. III f. 4, a longitudinal
section, showing the extremely thin lamelle perforated, as it were, by narrow tubes.
These cannot, as the following, be extraneous, later formed organisms, but must have
originated at the same time as the laminw of the shell, as it is clearly seen that these
laminz are bent exactly where the tubes are situated.

Almost the whole exterior stratum is closely perforated by what seems to me
to be a different, parasitic organism. When seen with a pocket lens of sufficient power
the surface is pitted by a number of irregularly placed, cream-coloured points (pl. III
f. 5) which are somewhat elevated above the surface. In a thin, vertical section these
white dots are seen to prolong downwards through the lamellx of the shell as tubes
which generally branch or anastomose so as to form three or four or even more branch-
lets (pl. Ill f. 1), all filled with the same uniform cream-coloured matter. In a trans-
verse section they are also remarked to subdivide and to form openings of stellulate
appearance (pl. II f. 2). Similar fossil and recent organisms have been found already
long before. Duncan‘) has described some small microscopic organisms, which pene-
trate the corals of the Devonian and Silurian times. K6nimKer’) has also more in full
described a great number of such minute, parasitic forms from several invertebrate
animals. Thus he mentions nine species of Gastropoda with perforated shells and he
makes the same conclusion as Wept before him, that this is due to fungous growth
or to the mycelium of microscopic fungi. The white radiating tubuli in the shell-
substance of Trybl. reticulatum make the impression of having been at first open and
then to have been filled with limestone of another kind. In the nearly related species
from Esthonia no such tubes are visible.

Length 40 millim., breadth 25 mill., height from margin of aperture 8 millim.

Found in the northern strata of Gotland, in Faré at Lansa, Lutterhorn, in the
limestone of Wialmsudd near Farésund, Svarfvare huk, in the canal at Westdds in
Hall and in the uppermost limestone beds of Slite. It belongs only to the higher
limestone beds of Gotland, possibly beginning at the top of b. In the Lower Silurian
of Esthonia at Borkholm, F. Scumiprs stage 8, a variety of this species has been found,
only distinguished by its thinner shell and finer reticulation, the interspaces between
the callosities of the surface being nearly of the same, small size over the whole shell.

2. Tryblidium unguis Linnst.
Pl. I figs. 33—37, pl. XIX fig. 2.

Tryblidium ungws 1880. Linpst. in AnceLin & Lou Fragmenta Silurica p. 16, pl. I, fig. 10—14, exel. fig. 15.

Shell of obovate outline, anteriorly acuminate, posteriorly expanded, with the
greatest breadth somewhat behind the median, transverse axis of the shell. It is re-

') On some unicellular Algz parasitic within Silurian and Tertiary Corals. Qu. Journ. Geol. Soc. 1876, p. 205.
*) Ueber das ausgebreitete Vorkommen von pflanzlichen Parasiten in den Hartgebilden niederer Thiere.
Zeitschrift f. wissensch. Zoologie 10r Bd 1860, p. 215.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 57

gularly and moderately convex, being most elevated near the median transverse axis.
The apex is close to the anterior margin and only very little prominent. The surface
of the shell is covered with thread fine ornamental lines parallel to the regular con-
centric lines of growth, somewhat interrupted by deeper sulci. It is generally even
excepting some wavy, irregular, shallow, longitudinal furrows. The aperture is oval
with comparatively thin margins, somewhat reflexed outwards. When seen from the
side it forms a moderately elevated arch, being highest near the median line of the
shell. The central space of the interior surface is surrounded by an oval ring of six
pairs of muscular scars, open anteriorly. The posterior ones are narrow and elongate, the
middle ones are transversally broad and much enlarged towards the margin of the shell.
The surface of these pairs is smooth or only partially scrobiculated. The uppermost
pair is more complicated and consists, as in the kindred species, of a more shallow,
elongated interior portion, and of a larger exterior one, from the inner corner of which
there projects a narrow sinuous groove, directed obliquely upwards and leaving a
small, smooth space between itself and the opposite similar one. The lower, interior
part of this upper, muscular scar is pearshaped, wide below, with a narrow, stalklike
neck upwards and its surface is finely reticulated by shallow pits and intervening
ridges. Some dark, narrow streaks are directed from the enclosed central space of the
shell towards the interstices between the muscular scars. The whole central part of
the shell inside the scars and to their outer edges is of dark colour, while the outer border
is lighter. Near the apex there is on the inside a little oval depression or pit, which
quite resembles a scar, filled up, as if there had been a foramen. But I think it is
in reality only the mark of the outlines of the initial shell, where now the apex is
seen on the outside. The shell is very thin, scarcely exceeding 0,5 millim. in thick-
ness and composed of thin, glossy lamella, which are not perforated by any parasite.
The largest specimen has been found at Stor Wede in Follingbo and has attained a length
of 67 millim., breadth of 51 and height of 15 mill.

This species has nearly the same geographical distribution as the former. It has
been found in several specimens in Faré at Lutterhorn, Lansa and Norsholm, in Svarfvare
huk, the canal near Westéds in Hall, Westkinde, Hiftingsklint, Lummelund, Stor Wede
in Follingbo, the limestone cliffs near Wisby and Kyrkberget in Wisby. It has only
been found in the strata 6 and ¢ or the upper and lower limestone and never in the
shale of a. This is rather unexpected as the same species or at least a nearly allied
variety, as mentioned above, has been found in the Lower Silurian strata of Esthonia
at Borkholm and also in the Upper Silurian at Koik, in the »Jérdensche Schicht». These
are only a little more elongate and not so enlarged as the specimens from Gotland. In
the Lower Silurian of Canada there occurs a Metoptoma Hyrie, of which Binuines, Pal.
Foss. Canada p. 87, has described a cast which also perhaps on closer examination
may be found to be identical. Met. Erato of the same author, 1. c. p. 39 and Report
Progr. Geol. Survey of Canada 1863 p. 145, f. 95, can searcely, as to outward shape, be
distinguished from the Gotland species, only the distance from the beak to the margin
is longer in the Canadian.

K. Vet. Akad. Mandl. Band 19. Niro 6. §

58 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

3. Tryblidium? radiatum n.

PIT XVII fig. Wye:

Shell oval, much eclevatedly conical, the greatest height lying near the middle of
the longitudinal axis. The apex anterior, truncated, curved as to lean forwards over
the anterior margin of the aperture. The shell between the apex and the margin is
consequently much concave. The apertural border is straight and horizontal. The
surface is covered by fine, closely packed, radiating striw and a few concentric lines
of growth. The shell has been thick, as may be seen by a few fragments which are
left along the borders. The general shape of this shell has led me to place it in this
genus, with the other species of which it corresponds as to its outline. This is, however,
more elevated like a Helcion.

Diameter from the apex to the hind edge 24 mill. The transverse diameter 20
millim. Height from the rim of the aperture 15 millim. Length of the aperture
23 mill.

Only a single specimen has been found in the crystalline limestone of Wialmsudd
near Farésund.

Fam. II. TECTURIDZ Apams.

Gen. PALAEACMAEA Hatt.

1873. 23d Rep. on the State Cab. of N. York p. 242.

Shell patelliform, aperture oblongate, eaterior surface concentrically wrinkled, on the
iterior surface near the top a wreath of muscular impressions, nearly coherent.

It is only provisionally that the Gotland species, described below, can be placed
within this genus. It is chiefly in consequence of its outward shape, which most re-
sembles that of Paleacmewa. In Hati’s specimens the muscular markings are unknown.
The Patelloid shells which are now and then found in the older paleozoic strata belong
probably to several different genera. ‘The »Patella» antiquissima from the Lower Silu-
rian of Sweden is nearly related to Tryblidium through its series of six pairs of de-
tached muscular scars. The typical species of Metoptoma, which as Dre Koninck has
shown have a coherent muscular band and consequently cannot, as Hatu |. c. has hin-
ted, be plates of a Chiton, agree with Lepetopsis in the conformation of this band. In
the Red Orthoceratite limestone of Oland at Wickleby Hr von Scumatenser has found
a specimen resembling a Metoptoma and another form probably belonging to the same
generic group of which Wnarrrime:p has given figures in Geology of Wisconsin, vol. IV
pl’ 3 f. 15, 17, 18, but which scarcely can belong to Metoptoma as he assumes. The

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. HS)

oldest Gastropod known in Sweden is Metoptoma Barrandei Liynarsson from the Cam-
brian strata of Scania, in the lower portion of the zone of Paradoxides Tessini.

Paleacmea’? solarium n.

Pl. XIX fig. 3, 4.

Shell patelliform, regularly acuminate, apex nearly median or slightly anterior,
the outline oblongate from above. Outside of the shell smooth, only concentrically
wrinkled at regular distances by larger elevated ridges, the interstices between them
being finely striated by parallel lines. Interiorly there is around the apex a narrow
circle of detached muscular scars, visible on the nucleus as delineated in the figure.
Height 3 millims., length 6 mm., breadth 4 mm.

Hitherto two specimens have been found in the red, conchiferous limestone of
Sandarfve kulle.

Fam. IV. CALYPTRAHID Bropkerip.

Gen. PLATYCERAS Conran.

1809 Helicites Martin Petref. Derbyensia, pl. 40 fig. 43.

1810 Capulus Montrorr Conch. System. II, 54; though not intended by him for fossil species, it was
adopted for such by DE Kontnck Anim. Foss. de Belgique, 331.

1812 Pileopsis Lamarck adopted by Sowrrsy Min. Conchol. vol. VI pl. 607, 223.

1823 Actita Fiscupr von WatpHemm Mém. Soc. Imp. Naturalistes de Moscou VI, 234.

1828 Turbinites Histncer Anteckningar IV, 221.

1840 Platyceras Conrab Aun. Rep. Geol. Surv. N. York, 205.

1841 Acroculia (rectius Acrocylia) Paittirs Pal. Foss. of Cornwall, 93.

1842 Platyostoma (rectius Platystoma) Conrap Journ. Acad. Nat. Se. Philad., 275.

1843 Orthonychia Hatu Rept. 4th Distr. N. York Geol. Survey, 172.

1844 Naticopsis Mac Coy p. p. Synops. Carb. Foss. Ireland, 33.

1859 Strophostylus Hatt 12th Rept. State Cab. N. York, 20.

1859 Zgoceras Haut Pal. N. York vol. Ill, 330.

1868 Exogyroceras Meek & Wortuen Geol. Survey Illinois, vol. III, 508.

1878 Capreolus KR. Erneriper Sr. (lapsu!) Qu. Journ. Geol. Soc., vol 34, 603.

Shell globose or naticiform with small, depressed or only moderately prominent
spire, last whorl enormously developed, globose or transversally protracted and elongated.
Aperture circular or oval, outer lip reflected and enlarged into a thin laminar edge, which
in well preserved specimens is persistent during the continued growth of the shell and gives
the exterior surface a characteristic ornamentation of projecting, thin laminw. The inner
lip of the aperture much varying; sometimes with twisted (»Strophostylus»), sometimes thin
and smooth columella (»Platyceras»). No operculum has ever been found.

In justification of the above list of synonymous genera the following statements
of the opinions of various authors upon this matter may be adduced. ‘The earliest
description of any fossil belonging to this group is in Marrrys Petrificata Derbyensia

60 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

plate 40 fig. 34, where he names a Carboniferous species as Helicites auricularis. Next
him Fiscuer von WALDHEIM comes, who in 1823 in a list on the genera of Gastropoda
gives Actita as identical with Capulus and Pileopsis. This is in a treatise called »Ad-
versaria zoologicay Fasciculus I] in the Mém. de la Soc. impér. des Nat. de Moscou
vol. VI p. 234. That he therein also included the palwozoic species is evident, when
he later in a paper of Faurenxont in »Bull. de Moscow» 1844 p. 802 describes an Ac-
tita Miinsteriana from the Carboniferous limestone of Moscow. If Fiscurr really in-
tended this genus for the palwozoic forms alone, his name ought to have the priority
against the later, as Platyceras, but it is by his first publication evident that he gave his
genus quite as wide limits as already had been given to Capulus and Pileopsis. Actita
then must be considered only as a synonym. In 1828 Hisincer in his Anteckningar,
pt. 4, p. 221 mentions a Turbinites, which he also figures, and this is the same which
he later, 1837, in »Lethza» named Pileopsis cornuta. In respect of the genus he fol-
lows the elder Sowerby, who 1835 in his Mineral Conchology placed the English Car-
boniferous species in the genus Pileopsis. When Conrap in 1840 had founded his ge-
nus Platyceras for the paleozoic fossils of this group and Puitups in 1841 his genus
Acroculia') for the same, the subsequent American authors sided with their countryman,
and the English ones with their, in spite of the former name having the priority and
that with such a tenacity that it lasted until 1851 when S. P. Woopwarp in his Manual
accepted Platyceras instead of Acroculia. Besides, the opinions of the authors were di-
vided between accepting the older genera Capulus or Pileopsis. Dr Konincx is the
first who insisted on adopting the genus Capulus of Monrrorr for the palwozoic spe-
cies and especially those of the Carboniferous formation. Since Merk and WorrHen
in 1866*) announced that they had discovered horseshoe shaped muscular scars on
casts of two species, Platyceras subplicatum and PI. infundibulum, almost all authors
were unanimous to range these fossils with Capulus. Merrex and Worruen, however, ex-
pressed as their opinion that these fossils »probably» are »distinct from the existing
genus Capulus», but that they are more nearly allied to that group than is generally
supposed to be the case. Moreover it may be questioned whether Plat. subplicatum
and kindred really belong to the same genus at the Silurian ones. It has been found
only in casts. As to the other species, of which only one specimen has been found,
the last mentioned authors themselves seem to hesitate with placing it amongst the
Platycerata. I have myself studied the’ interior surface of several specimens of Pla-
tyceras wquilaterum from the Burlington beds, without finding in them the least trace
of any muscular scars. Nor have I-been able to find any muscular impressions in the
numerous specimens of the Silurian forms which I have examined. But this can,
however, not be conclusive as to the deficiency of the muscular scars in the paleozoic
species, because even in recent or tertiary Capuli the muscular impressions are very
faint and in many specimens not discernible, owing to the glossy surface of the shell.
It must then be very difficult and a thing of rare occurrence to detect them in spe-
cimens from palwozoic strata. Even if granted that these shells were provided with

1)-Or Acrocylia as it ought to be written according to the derivation.
) Proceedings Acad. Nat. Se. Philadelphia 1866 p. 262.

KONGL. SV. VE'T. AKADEMIENS HANDL. BAND. 19. N:O 6. 61

muscular scars as in Capulus, the globular, low or high spired forms which almost
‘insensibly merge into each other through numerous gradations unite them all at
least the Silurian ones, in one genus, which although probably a near ally to Ca-
pulus, still must be considered as distinct. In accordance with Hart and the Ameri-
ean authors I retain the genus Platyceras for the Silurian species. But I also think it
proper to unite within its limits the genera Platystoma and Strophostylus. These, as
may be seen by the following comparison, are indeed not much differentiated. Accor-
ding to the diagnosis given by Hat’) they are thus characterized:

Platyceras. Platystoma. | Strophostylus.

»Shell depressed, subglo-| »Shell subglobose; spire} »Shell subglobose or ovoid-
bose, subovoid or obliquely)short; aperture very large) globose. Spire small, with a
subconical. Spire small, vo-|suborbicular, dilated; labrum) large ventricose body-whorl;
lutions few, sometimes /ree joining the body whorlat right) outer lip thin, not reflected;
and sometimes contiguous|angles to the axis of the shell» columella twisted or spirally
without columella, aperture,,Conrap; »having columella,) grooved within, not reflected;
more or less expanded, often)columellar lip thickened.» umbilicus none: aperture so-
campanulate and sometimes HA... mewhat round-ovate or trans-
with the lip reflexed: peri- versely broad oval.»
stome entire or sinuous». |

Consequently, the chief differences are that in Platyceras there is no colu-
mella and in Strophostylus a twisted columella and Platystoma is nearly related to
Strophostylus. In the latest volume of »Paleontology of New-York», vol. V pt. II p.
129, Hatt seems to hesitate about the distinction of the two first genera. »Platystoma,
he writes, vis in some species scarcely separable from Platyceras by any persistent
characters». Barrots and other later authors agree with Haru in this point. But Stro-
phostylus is also not tenable as the twisting in the columellar part of the reflexed
lip is seen in specimens which else agree with Platyceras. Pl. II fig. 37—38. Even
if Platystoma did not coincide entirely, as it seems to me, with Platyceras, this name
could not be retained, as it has been preoccupied already several times before’). If
we now turn our attention to the numerous figures given by Haun and to specimens
from North America, we cannot fail to remark the extreme amount of variation, through
which the forms are mixed up with each other. It is indeed very difficult to find
any difference between the reflexed lip along the body whorl in Platyceras and Pla-
tystoma and the so called »twisted columella» in Strophostylus, which is in uninter-
rupted continuation with the outer lip and has no such separate callosity as in Natica
for instance. Moreover, in many of the specimens figured on plate XI, vol. V pt. I
of the Paleontology of N. Y. the »columella» is neither twisted nor grooved. In con-

1) Pal. of N.-York, vol. III pp. 299, 303, 309.
*) 1753 Platystoma Kier (= Helix, Ampularia, Natica & Nerita).
1803 Platystoma MetcEen a dipterous insect.
1829 Platystoma AGassiz a fossil fish,
and moreover Lause in his work »Gastropoden der Hallstiitter Schichten 1855, has also named a new genus
of his Platystoma.

62 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

sequence of what now has been adduced I cannot but consider Strophostylus also as
identical with Platyceras.

Besides, the highly variable and proteic forms of this genus have been ranged
within many other genera of which some are enumerated here below.

Exogyroceras a subgenus proposed by Mrrx and Wortnen in 1868, Geol. Survey
of Illinois vol. HI p. 509 for shells with a sinistral spire and obscure columella.

Igoceras Haru. Established by Harz in 1859 in Pal. of New-York, vol. III p.
330. It differs from the straight Platycerata (Orthonychia) only in having the surface
cancellated and it can consequently not be retained on so trifling a distinction.

Natica Apayson. Both Prcrer and D’Oxzieny think that this genus occurs in
the Silurian formation, but such species as Natica parva, Natica spirata or Wenlocken-
sis (Sow. Sil. System pl. 5 & 12 and D’Orsieny Prodr. I p. 29) are true Platycerata.
It is possible that also some of the Bohemian Natice, N. gregaria for instance, belong
to this group.

Nerita L. is employed by Sowerby in the Silurian System for the most common
Platyceras.

Orthonychia Hatt Rept. 4th distr. N.-York Geol. Survey p. 172 is a subgenus,
created for the straight Platycerata, forming an elongate cone, with small spire and
the ultime part very large. In the 12th Report N.-York State Cab. p. 18 Hati de-
clares that a renewed examination has not shown any reliable characters, by which
they may be separated from Platyceras. Meek and Worruen, however, retain this name
and it might perhaps be advisable to do so for all those species which are invariably
straight or scalaroid.

Then there may be some few species which belong to this group, but have been
placed with the genera Holopea, Isonema, Naticopsis. Professor Ferp. Rormer placed
one of the forms of P]. cornutum in the genus Cyclonema.

D’Orsieny made use of Stomatia for one of the Lower Silurian Platycerata.
Prodr. I p. 29: In how far the genus Poly(o)stomella of R. Eruermper jr') can be
considered as related to Platyceras, I must leave undecided as I have not seen any
specimens belonging to it. On the other hand it is likely that some fossils have been
ranged with Platyceras, which in reality do not belong there, as for inst. some of
SANDBERGER’S °).

The chief difficulties in the study of this genus are the dissimilar state of pre-
servation of the exterior ornamentation of the shell and the almost incredible varia-
tions in its shape and growth. Some authors, as Morris in Qu. Journ. Geol. Soc. vol.
5 p. 332, write of a sinus in the outer lip of »Acroculia» nearly in the same sense as
the remarkable one in the Pleurotomaride. But besides that every sign of it is often
wanting in most specimens, there is by no means in those provided with it such a
great regularity as in the Pleurotomaridex, as there is only a wavy line, sometimes in
the Orthonychide several, corresponding with the indentures in the apertural margin.
If there is more than one sinus there are also quite as many wavy bands. These are,

1) Proc. Roy. Phys. Soc. Edinburgh. 1880 vol. 5 p. 163.
*) Versteiner. Nassaus. pl. XXVI fig. 18, Cap. psittacinus.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND (9. N:0 6. 33

however, not bordered by elevated lines as in the Pleurotomaride, they resemble more
what is seen in the recent Ianthinaw, which also sometimes exhibit such notches.

Probably much in consequence of this slight resemblance with the last mentioned
group, some authors have given Platyceras (— Platystoma) its systematic place with
the Tanthine. Haut in the fifth vol., Id part of Pal. of New-York, has signed the
plates on the Platycerata as Ianthinidw for Platystoma and Strophostylus, and Platy-
ceride for Platyceras, but in the descriptive letterpress he is willing to unite all three
genera into one genus. The thin and fragile shell of Ianthina is not corresponded by
the thick and heavy one in Platyceras. Other authors, again, as SroticzKa') and Waa-
GEN”) see the affinity of the Platycerata with Velutina, to which several of them show
some resemblance in the exterior shape of the shell. Platyceras may, however, as has
been shown above, most fitly be ranked with the Capulide, with which they also share
the peculiarity in habit of fixing themselves closely with the aperture to the surface
of other marine animals, especially Crinoids.

In Sweden the oldest Platycerata found are from the beds of the Leptena lime-
stone of Dalecarlia, from where five different species have been described’). At least
two of the Gotlandic species are also found in the Upper Silurian of Scania. The
shells of this genus have been the most common of all Gastropoda in the palwozoic
seas. While in the Silurian epoch Platyceras cornutum and others of spirally coiled
forms were prevalent, in the Devonian of Harz and North America and still more so
in the Carboniferons strata, especially the North American, the straight forms which
constitute the subgenus Orthonychia are most abundant.

The Gotland species may be arranged as follows:

I. Platyceras proper, with spire coiled of three or four whorls and almost en-
tirely or nearly contiguous with the body whorl.

1. Pl. cornutum His.

2. Pl. cornutum, var. loricatum n.

3. Pl. prototypum Puutrrrs. *)

4. Pl. disciforme n.

Il. Orthonychia spire diminutive or evanescent, shell straight, tubular.

5. Pl. enorme n.

6. Pl. cyathinum n.

1. Platyceras cornutum Hisinerr.

Pl. II figs. 29-—51, pl. Ill figs. 6-—9, 19—26.

Turbinites. 1828. Huistnger Anteckn. [V, 221, tab. VI f. 6.

Pileopsis cornuta. 1857. Histnerr Lethaa Suecica, 41, pl. XII f. 11
1848. Bronn Nomenclator, 973.

Pileopsis suleata. 1837. Huistnarr Lethea, 41, pl. XII f. 12.

1848. Bronn Nomenclator, 974.

') Cretaceous Fossils of India p. 319.

2) Salt-Range Fossils p. 103.

3) AnceLIn & Lrypstrom. Fragm. Sil. p. 14.

4) By inadvertence this species was named P. spiratum Sow. in the list, page 16.

64 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

? Natica ylaucinoides. 1839. Sow. Sil. Syst., 603, pl. 3 f. 4.
1843. Morris Catal. Brit. Foss. 1st Ed. 154.
Natica parva. 1839. Sow. Sil. Syst. 612, pl. 5 fig. 24.

1843. Morris Catal. 153.

1848. Bronn Nomencl. 786.

1848, Purittips Mem. Geol. Survey, Il, 259.

1854. Morris Catal. 2d Ed. 263.

1854. Savrer in Murcurson Siluria 2d Hd., pl. XXV f. 1.
Pileopsis vetustis (2? = yetustatis), 1839. Sow. Sil. Syst. 616.
Nerita haliotis. 1839. Sow. Sil. Syst. 625, pl. 12 f. 16.

1843. Morris Catal. 154.

1848. Bronn Nomenel. 805.

1862. Mac Coy Sil. Foss. Ireland, 13.

Capulus neritoides var. suleata. 1848. Bronn Nomencl. 217.
Natica subparva. 1850. D’Orpieny Prodr. 29.
Capulus haliotis. USO inal os Sil,

1854. Morris Catal. Ed. 2, 239.

1855. Mac Coy Pal. Foss. 290.

1857. GiesrL Zeitschr. f. gesammte Naturwiss., 165.
Capulus enomphaloides. 1852. Mac Coy A. N. H. ser. 2. vol. 10, 196.

1854. Morris Catal. 2d Ed. 239.

1855. Mac Coy Pal. Foss. 290, pl. 1 K, f. 39.

Platystoma niagarensis (= e). 1852. Haw Pal. of N. York vol. II, 287, pl. 60 f. 1.
1860. F. Roemer Tennessee, 75, tab. V f. 15.
Acroculia haliotis. 1854. Savrer Siluria 2d Ed. 230
1859. Ip. Siluria 3d Ed. 548 Seale

1871. Batty Figures of charact. Brit. Fossils, part. III, 64, pl. XXI f. 12.
1873. Satter Cambridge Fossils, 89, 154.
1874. ArH Galizien, 31.

Capulus Brauni. 1857. GirpeL Zeitschr. gesammt. N. W. 167; according to him Histnerr’s
Pil. cornuta is the same as Munsrer’s Cap. Brauni. Now, even if
it could be proved that they were identical, this latter species was
created some years later than Histncur’s and it would be contrary
to all rules of equity and priority to abolish the older name.

Capulus sulcatus. 1857. Gresser |. c. 166.

Acroculia cornuta. 1867. Ps ; a

Pe ae a “3 Linpstrom Nomina fossilium Gotl. 23.
Acroculia euomphaloides. 1873. Sauter Cambr. Foss. 171,

Naticopsis parva. 18735) Ips lee: 185:

Shell of highly variable shape, naticiform with prominent spire, neritoid with
depressed spire or planorbiform with sunk spire. Generally transverse or broader than
high, with the body whorl enormously developed. The ornamentation of the outside
is characteristic. It is very difficult to find specimens, which exhibit it sufficiently
clearly. They have mostly been subjected to the tear and wear on the shore before
being imbedded or suffered from corrosion or also been changed after their fossilization.
The ornamentation is of the same pattern in all, only changing in minor details. It
changes with the age of the shell, different in the young and the adult or on the spire
and the last whorls. It consists of two sets of lines, which intersect each other. There
are delicate, wavy, longitudinal lines, interrupted by the often irregular lines of growth
and other elevated lines. On the spire, pl. II figs. 830—81, the longitudinal lines are
threadfine, elevated, with interstices many times surpassing their breadth and at regular
distances they are interrupted by the transverse lines. On the body whorl near its
middle line they have increased in size, with minute, microscopical lines between the
large transverse ones. On the inferior side the longitudinal lines are large, broad,

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 65

densely set, as it were, in groups of two or three with smooth interstices. They are
wavy or interrupted in their continuity by the transverse lines. As is seen on pl. II
f. 36, they form minute, steplike gradations or, as it were, terraces, each of the upper-
most ones lying a little higher, than the succeeding inferior. The transverse lines form
a sigmoid bend when they, more or less crowded, more or less prominent, continue
from the suture to the umbilical side. The coarser ones which in most instances re-
present the outlines of former apertural lips are wavy or notched by two or three
angular slits. On the spire they end towards the suture as a thin and sharp lamina,
which bridges over the suture to the next whorl.

The spire is short in the most common variety, depressed and, as stated, even sunk
in specimens which are planorbiform. The whorls vary in number from three and a
half to four and a half. The last one is sometimes so much enlarged and widened,
that it surpasses the spire with the lower rim of the aperture. The suture is tolerably
deep.

There is a tendency in the body whorl to grow out free, without any connection
with the older whorls, as is manifested in several specimens delineated on plate II. In fig.
48 it is just beginning to free itself, in figs. 50, 51 it is disconnected for a longer distance
and tubular and in figs. 47 & 49 the whorls are nearly uncoiled. This is an approach to what
is permanent in the younger Devonian and Carboniferous species and also in the Silurian
Orthonychix. This peculiarity in the formation of the shell is what the German authors
call »Skalaridenbildung», and may be found amongst several recent shells, where the
last whorl as in Vermetus is free and tubular. Scalarid shells live together with nor-
maly coiled of the same species, and races, varieties or even new species may take their
origin from them if they prevail and persist. Thus resembling forms of analogous
formation may arise or be repeated in genera which are not in the least related.

The aperture is oval, oblique or transverse, its margins thin or thickened, the
columellar lip reflexed or in some specimens only in a small degree hiding the umbi-
lical fissure. Sometimes it is so much developed that it completely covers the umbi-
licus, and thins out against the whorl, pl. II fig. 29. In some this lip, pl. II f. 37,
38, is thick and twisted and shows thus the characters of the genus Strophostylus.
The exterior lip is regularly bent, sinuose or lobate. In pl. II fig. 52 and still more
so in pl. III fig. 6 there are instances given of a highly sinuose aperture. In fig. 6 it
is wrinkled and bent in several creases and folds. This is probably owing to the
circumstance that they have been fixed to the shelly surface of some other marine
animal and long time enough to have moulded the aperture according to the sculpture
of this substratum. As is the case with the [English and American specimens of this
species and also with Platycerata from the Carboniferous formation of North America,
these shells are sometimes found fixed on the perisome of Crinoids, as for inst. on Perie-
chocrinus. When such sinuosities occur in the outer lip there is formed on the median
line of the body whorl what in a distant manner reminds of the slit band of the Pleuro-
tomariz. It consists of the wavy lines of growth on the fornier site of a sinus. In

others, as in the specimen which is the original type of H1stverr’s Acroculia suleata
K. Vet. Akad. Mandl. Band 19. N:o 6 )

66 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

(pl. Il fig. 52), there are at irregular intervals longitudinal, revolving grooves one or
even as many as three and the surface with its lines of growth assumes a scaly or
imbricate appearance. In one variety from the lowest shale beds of Wisby there is
regularly a groove and an elevated ridge around the umbilicus.

In another form of the aperture there are large tonguelike lobes (pl. II fig. 41
& 42), giving not only the aperture, but also the shell an irregular shape.

On the inner side there are, as can best be seen through the casts (pl. II figs.
44 & 45), large transverse ridges or weals especially in the last volution and which
are seldom seen on the outside. Although I have carefully searched for muscular scars
on the inside of many well preserved specimens, I have never succeeded in finding
such. On the inside of the body whorl a pocket lens reveals a peculiarly streaked
surface of bifurcated and sinuous or branching lines with jagged borders in faint relievo
on a dark surface. PI. III fig. 23. A horizontal, thin section, made deeper below this sur-
face presents the mottled appearance figured on plate III figs. 25—26. Vertical sections of
the shell, magnified through the microscope are seen in plate III figs. 19—22. Of these
fig. 22 shows three distinct strata, the outermost very thin, the median one composed
of transparent prisms, the innermost, which is the thickest, is darkened through inter-
spersed, small, black grains, which probably have been added during the process of
fossilization. In other sections this stratum is composed, figs. 19—20, of angular lines
of growth, resembling those which are seen in PI. prototypum.

Dimensions of the specimen figured pl. II fig. 32—83. Height 21 mm., breadth 24
millim. Spec. figs. 39—40 height 30 millim., breadth 32 millim. Specim. figs. 34—35
height 15 millim., breadth 15 millim., height of spire 5 millim. Largest specimen, from
Lindeklint, 42 mill. in height, 41 mm. in breadth.

This, the most common of all Silurian Gastropoda of Gotland, has been found
almost everywhere, and in all strata between Hoburg and the northernmost point of
Fard. The largest specimens are as a rule found in the higher strata, as in the red
limestone of Sandarfve kulle and Linde. The old truth that species which are widely
spread and very rich in individuals, also are highly variable and as a rule even have
a long duration in geological time, holds in the fullest sense good with this species.
The first impression one gets when glancing at the bewildering dissimilarity of forms
delineated as Platyceras cornutum on the plates Il and III is that we have to deal with
a great many different not only genera but also species, and the above list of synonyms
shows indeed how the opinions of the authors run in many different directions. But
by patiently comparing a large number of well preserved specimens from the same
locality, the conviction forces itself upon the mind, however reluctant it may be, that
they all belong to the same species. Variable as many of the Silurian Gastropoda are,
this is the most variable of them all. It is difficult to decide whether this species is
one of those plastic groups which truly may be called the main source of several diffe-
rent new specific forms or if it be one of those mocking species which easily assume the
shape and features of others, often not at all related.

The most common of the Gotland forms is that which resembles Sowerny’s Ne-
rita haliotis. It seldom attains so large a size as the English specimens, but it enti-

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0O 6. 67

rely agrees with it in shape and ornamentation. Another common form is similar to
Capulus euomphaloides of Mac Coy. There cannot be much doubt that when the various
American species of Platyceras, Platystoma and Strophostylus have been sufficiently
throughly examined, they may prove to contain many identical forms. Specimens sent
to me from Mr S. A. Mitrer in Cincinnati as Platystoma niagarense, do not in any
sensible degree differ from certain varieties of Platyceras cornutum. This, however, in
the European strata never attains such a great size as the American ones.

As to the geological duration of this species it seems to have continued also
during the Devonian epoch, as it probably is identical with or nearly related to the
Devonian Pileopsis prisca GOLDF. p. p.

2. Platyceras cornutum, var. loricatum n.

Pl. Il, figs. 53—57.

Shell planorbiform, spire depressed or hidden within the volutions of the large
and tumid body whorl. Surface imbricated by transverse, wavy lamine which project
in a thin edge, fig. 58, above the surface, and include thickset, threadfine longitudi-
nal lines. The transverse lamelle are more distantiated near the aperture than on the spire.
The whorls are three or at the highest three and a half, rapidly decreasing in width towards
the apex. The aperture is oval or lobate, forming grooves which continue on the body
whorl. The sinuosities of the aperture are seen a long way up this whorl through the
wavy lines of growth. The inner lip is straight, not reflexed. The spire is often so
sunk as to be nearer the umbilical side of the shell than the apical. Height 8 millim.,
breadth 12 millim., in another specimen height 9 millim., breadth, 15 millim.

This variety which by transitional specimens is linked to the preceding, has been
found near Nya Slitegards in Dalhem, and in the limestone of Klinteberg.

3. Platyceras prototypum Putuies.
Pl. III fig. 10—18.

Nerita spirata? var. 1839. Sow. Sil. Syst., 625, pl. 12 f. 15.
1843. Morris Catal. 154.
1848. Bronn Nomenclat., 806.
Nerita prototypa 1848. Puitirs Mem. Geol. Surv. I, 358.
1854. Morris Catal. 2d Ed., 264.
Natica Wenlockensis 1850. D’Ors. Prodr., 29.
Acroculia prototypa 1854. Savvrer in Siluria 2d EHd., 230 ee
1859. Ib. ib. 3d Ed., 548 pl. 24 f. 8.
1871. Batny Figures of Charact. Brit. Fossils pt ILL 64, pl. XXI f. 11.
1873. Saurer Catal. Cambridge Foss., 154.
Strophostylus cyclostoma 1864. Hau p. p. Transact. Albany Instit. vol. IV, 218.
Cyclonema brevispira 1876. Ferp. Roemer Leth. Geogn. Taf. 14 fig. 14.

Shell naticiform, globose, with prominent acuminated spire. The ornamentation

nearly of the same pattern as in Platyceras cornutum, only finer and denser. There
are the same sort of graduated, wavy, longitudinal lines, and elevated, threadfine trans-

68 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

verse lines. The grooves formed by these are deeper in the specimens from Sandarfve,
than from Wisby. In the specimens from Klinteberg, figs. 10, 10a, the sculpture is
only discernible on the apex. On the body whorl it is quite obliterated and covered
by coarse transverse lines of growth. The whorls are five, tumid and globose, the
body whorl being many times larger than the preceding ones. The suture is deep
and narrow. The aperture is oval, longer than broad. The lips are continuous
all round the aperture in the adult, pl. III figs. 10, 13; fig. 11 probably still
young. The margins of the aperture are widely reflexed, so as to give it a trumpet-
shaped form. As seen in figures 10a, 13 & 14, the aperture is thickened through the
accumulation of the lamellar lips. Especially this is evident in specimens from the
fine-grained limestone of Sandarfve kulle in which a great number of apertural lamella
are preserved. PI. III fig. 17. There are in this instance no less than seventeen such
reflexed, apertural lamelle left behind in their old place during the progressive growth
of the shell. Seen through a microscope they show angular strata of calcareous spar.

Height 23 millim., breadth 26 millim.

This species has been found in many specimens in the shale of Wisby, but espe-
cially in the uppermost limestone beds of Sandarfve kulle, Klinteberg and Lilla Carlsé.
There are specimens from Lansa in Faré and from Follingbo, more largesized and with
lower, blunt spire, which possibly may belong to this species, but the surface is too
corroded to show any sculpture and the aperture is obscured.

Specimens sent from Mr S. A. Mitier in Cincinnati as Strophostylus cyclostoma
agree perfectly as to the ornamentation, but I cannot find the form of the aperture
in them.

4. Platyceras disciforme n.

Pl. II figs. 73—78, pl. XIX fig. 5.

Shell discshaped or flat; whorls three and a half or four, the last free and without
any connection with the others. The dorsal or exterior part of the whorls is thin and
almost sharpedged, the opposite part being much higher. The spire of the three con-
nected whorls is low and not visible above the other shell. The last whorl is enor-
mously large, widening at the point where it becomes free, from 7 millim. to 28 mil-
lim. at the aperture. The aperture is of a shape between elliptic and triangular, nar-
row at its exterior lip, then widening and at highest near the median line, the inte-
rior lip so much reflexed as to touch the back of the spire. The surface is wrinkled
by transverse undulating lines of growth which are bent forwards toward the aperture
more at the dorsal side than at the opposite. There are moreover delicate, longitu-
dinal, threadfine stria somewhat wavy and interrupted where they are crossed by the
transverse lines.

Height at the columellar side of the aperture 15 mill., breadth 39 millim. In all
six specimens have been found in the sandstone of Hoburg, and a few also in the su-

perjacent limestone of Nackshejd and Klef in Wamlingbo and Sundre.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 69

5. Platyceras enorme n.
Pl. If figs 59—72.

Theca anceps 1859. Fx. Scumrp (nee Puriitrs) Geologie der Insel Gotland, Archiv Naturk. Wstlands Bd I, 442.
Theea sp. 1867. Lriypstrém Nomina, 23.

Shell straight, cylindrical, with a diminutive spire of one and a half whorls. Many
specimens are curved as a crescent or a bow. The last whorl is considerably develo-
ped and large and the spire has dwindled to a mere appendage to it. In its general
shape the shell thus resembles a diminutive Lituite. The surface is covered by trans-
verse, sinuous strix, the edges of which in the best preserved specimens project as thin
reflexed lamelle with smaller ones between them. Pl. II f. 72. These are intersected
by fine, longitudinal lines, interrupted by the transverse ones as seen in fig. 71. The
aperture, figs 66, 67, is oval or circular with thin lips, often sinuous or wavy. Length
17 millim., diameter at the aperture 8 millim. From the shale at Djupvik in Eksta,
Rikvide in Nar, in the sandstone of Bursvik, in the oolitic beds of Hafdhem, Nas and
Bursvik, and in the limestone beds at Hammar in Kraklingbo, Klinteberg and Lanna
near Slite, from which last locality the Mineral Cabinet of the University of Upsala has
obtained specimens, collected by Professor P. T. Cieve.

This species and the following belong to that group of the Platycerata, which
J. Hatt has called Orthonychia and which is so prevalent both in the Devonian and
the Carboniferous limestone strata.

6. Platyceras cyathinum n.

Pl. VII fig. 22.

Shell conical, nearly straight without spire of whorls, rapidly increasing in width,
spirally twisted in two bends. Surface concentrically striated by fine transverse lines
of growth and wrinkled in the same direction. Aperture circular with thin edges.
Shell thick, consisting of several strata, glossy, opaque with only faint traces of prisms.

Length of the single specimen found 30 millim., breadth of aperture 20 millim.,
at the apex 2 millim.

Only one specimen has hitherto been found in the Crinoidal limestone of Fol-
lingbo.

This species is related to the Bohemian Capulus anguinus Barranpe and kindred.

Fam. V. BELLEROPHONTIDA Mac Coy.

Shell globular or discoid, symmetrical or slightly deviating from the discoid plan,
aperture widened with an angular slit in its dorsal or superior edge, forming by conti-

70 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

nued growth a slit band, which assumes the shape of an elevated keel or also a sunk,
shallow groove; its inferior margin covering a part of the back of the preceding volution.

Table of the genera:
A) Slit band entire, continuous without any openings.
1. Shell globular, involute, apertural lips wide, trumpet shaped. Slit band
broad, sunk.
Bellerophon Montrorr.

2. Shell disciform, laterally compressed, aperture hastate, whorls in several species
not involute, free and not contiguous. Slit band elevated, often forming a sharpedged keel.

Cyrtolites Conran *)

B) Slit band always clevated, perforated by a series of oblong openings. Aper-
ture many times wider than the volutions, ornamental lines spiral. Shell discoid, in-
volute.

Tremanotus HA.

As to the systematic place of this family every one conversant with the concho-
logical literature is aware that there are few palewozoic genera on which the opinions
of the authors have been more divided and differed more widely. For a succinct sur-
vey of these varying opinions it is enough to refer to the works of Dr Koninck”), MerK®)
and Waacen’), where a relation is given in full. Bellerophon has been placed amongst
the Cephalopoda by its first discoverer Hivscu, by its denominator Monrrorr, by Dz
Francr, Mac Coy, Pumuiprs, Porrnock and Curnu. It has been considered as one of
the Heteropoda by Sowrrsy, D’Orsieny, Brony, Desuayes, D’Arcutac and Verneuin”)
Puiwurrr’), Eicnwatp, Owen’), Satter, Woopwarp*) and Apams. It has been numbered
amongst the Gastropoda by Buarmyvitte and Va.encrmnnes (as related to Acera and
Bulla), Fremine (as Actwon), De Konrnck and Picrer (to Emarginula »comme un lien
perdu entre les Emarginules et les Pleurotomaires»), JAmMes Hai, SANDBERGER, (joining
them with Pleurotomaria through Porcellia), Meex and Worruen. Among the most
recent authors SroriczKa’) hesitates between placing Bellerophon in the Heteropo-
da, Opisthobranchiata and Cephalopoda. Inenine*’) denies the affinity of the Bel-
lerophons to the recent Heteropoda and places them in a family of their own, quite

") A new generic type, intermediate between Bellerophon and Cyrtolites is probably formed by the spe-
cies named B. norvegicus by Broaeer in his »Silurischen Htagen, p. 53.

*) Animaux fossiles de la Belgique p. 334.

3) On the affinities of the Bellerophontidee in Proce. Chicago Ac. Se. Vol. I, p. 9.

1) Paleontol. Indica. Ser. XIII p. 126.

°) Geol. Transactions vol. VI, p. 3285.

*) Handbuch der Malacol. p. 285.

1) Paleontology p. 72.

*) Manual of Shells p. 201 to Atlantidie, but in the Supplement edited by R. Tare in 1868 it is placed
as a subfamily to the Pleurotomariz amongst the Haliotide.

) Paleontologia Indica. V. Gastrop. p. 393.

) Nervensyst. der Mollusken p. 143.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. wn:o 6. 71

as Mac Coy already had done before him. But there is no reason to couple them
with the Capulide as Inertnc does, when he thinks that Carinaropsis is the connec-
ting link. This genus is no doubt composed of incongruous elements, some being real
Bellerophons, others Capulide or even Patellidw. The remark of SroniczKa that the
Lepetide are near to Cyrtolites (»Some of the species of Anisomion exhibit a great
relation to species of the palwozoic Cyrtolites, like C? expansus»), loses all its founda-
tion, as it is evident that Cyrtolites expansus of Har is no Cyrtolites, but a Platy-
ceras.

Merk (I. c.) lays, as it is quite right to do, much stress on the aflinity of Tre-
manotus with Bellerophon and Bucania on the one side and with Haliotis and Pleuro-
tomaria on the other. He concludes: »In other words it indicates for the family a
position near the Fissurellide and Haliotidw, and between these groups and the Pleu-
rotomarid».

Waacen (1. c. p. 130) holds the opinion that a more or less close affinity of the
Bellerophontide to the Pleurotomaridex is highly probable. What makes the Bellero-
phons approach the Pleurotomariz is a tendency observed amongst some to grow some-
what obliquely, thus nearing to the conical spiral. In accordance with Dr Konincx") as
this author formerly has stated, I do not think it advisable as Waacen has done, to place
within this group such forms, which, although resembling the Bellerophons in the
general form of the shell, do not show the least trace of apertura] sinus nor of any
slit band. Dr Konrncx holds that such are young Goniatites and it is remarkable that
in the Silurian formation, where no Goniatites are found, also such Bellerophon-like
shells without any slit band are wanting. Such forms are comprehended in the new
genera, which WaaceEn (I. ¢c.) has proposed under the names Warthia, Mogulia and
Stachella. The same is also the case with Mrrk’s Bucanella and Mac Coy’s Euphemus,
though Dr Koninck and Waacen have again adopted the last genus. The slit band
must indeed be considered as one of the most important, if not the most prominent
character of the shell itself. Still it is very difficult absolntely to decide this as well
as other cases of affinity amongst the paleozoic shells, as there may be other genere
as for inst. Scissurella, with a distinct slit band on the shell, without any affinity be-
tween the animal itself and that of Pleurotomaria.

For my own part, I feel inclined to follow the precedence of Merk and accept
the Bellerophontide as most nearly related to Haliotis, a view in which Dr Koninck
also in his last work participates. This view is strengthened by the similarities which
are offered by Tremanotus with its perforated slit band and the sculpture of the sur-
face which in so eminent a degree reminds of that of Haliotis. This position, however,
cannot but remain hypothetical, as no more valid grounds taken from interior resem-
blances and homologies between the soft parts of the animals can be gained. Nor is
there anything in the microscopic structure of the shell that either corroborates or
contradicts such views. Not the least trace of any nacreons stratum has been found
in the Gotlandic Bellerophontide.

1) Mem. de la Soe. Roy. d. Se. de Liége. 1878, p. 340. Fossiles paléozoiques de la Nouvelle-Galles du Sud.

72 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Gen. BELLEROPHON Monvrort.

Syn. 1781 Nautilites Hipscu p. p. Naturgeschichte des Niederdeutschl. I, 23, pl. HI f. 20—23.

1808 Bellerophon Montrorr Conchyl. Systematique, I, 50, 51.

1812 Ellipsolithes Sownrsy p. p. (non Montr.) Min. Conch. vol. 1, 81.

1825 Bellerophus BuatNviutn (»mala emendation Hnrmansen) Man. de Conchyliologie, 4.

1847 Bucania Haut p. p. Pal. N. Y. vol. 1, 32.

1847 Carinaropsis Hatt p. p. Pal. N. Y. vol. 1, 183.

1849 Vasulites HprmaNnsen (non Monte.) Ind. Gen. Malac. Primordia I], 677. See below.

1861 Phragmostoma Haun 14 Rep. N. Y. State Cab., 94.

1882 Waagenia De Kontncx Notice sur la famille des Bellerophontide, Ann. Soc. Géol. de Belgique IX, 14.
This name being already given away by Neumayr it was changed by De Koninck into the fol-
lowing.

1883 Waagenella Dp Koninck Faune Carbonif. Belg. II pt. IV. Explic. des planches, pl. 38.

Shell globose, involute, with the whorls in the same plan or nearly so, concave on
the umbilical side as well as on the apical one, so that no distinction can be made between
them. Aperture circular or oval, suddenly much enlarged, lips thin, continuous, interior or
columellar lip covering the back of the second convolution. The slit band is always distinct,
originating from a deep notch in the middle of the eaterior lip; it is m several species
much varying, being elevated as a keel on the last convolution, sunk as a channel or a flat
hand lower down on the older whorls. It is covered with quite the same sort of semilu-
nar, backwards curved wavelets as are seen in all Pleurotomarie. The umbilicus is in
the small specimens very large and open and is in the older ones covered and hidden be-
neath the refleved margin of the aperture. In some, however, it continues uncovered or
open. The exterior ornamentation of the shell consists of transverse striw, which often are
crossed by longitudinal ones. Moreover there is a peculiar feature, observed in Gotland
specimens, consisting in a serics of thin laminw, which are nothing but the continuation of
the lines of growth. They are gently curved outwards and are most crowded and per-
fect in the umbilical tube, where they have also been best protected against fracture. These
lamine may as in Tremanotus, each in its turn, have formed the successive apertures and
then been partly absorbed, partly abraded and only preserved where they were protected.

In explanation of the synonyms given above the following remarks may serve.
Ellipsolithes Sow. in Mineral Conchology, vol. I pp. 81, 83, 84 is not to be confounded
with Monrrorts genus of the same name which only contains Polythalamia. That of
Sowerby consists of one species of Nautilus, one of Goniatites, and one of Bellerophon
(B. ovatus) according to his own emendation in Min. Conch. vol. 5 p. 107. But Mor-
ris, Cat. Brit. Foss. p. 302, regards them all as Cephalopods. Bucania Haut Pal.
N. York vol. 1 p. 32 is chiefly distinguished thereby that the aperture is dorsally
abruptly expanded and that the volutions are all visible in the umbilicus. In the
fourth volume of Pal. N. York Hatt seems to have abandoned his opinion on the di-
stinetion of this genus and includes it amongst the Bellerophons. The wide aperture
is moreover common with most of the Bellerophons and as to the uncovered and
large umbilicus Desnayrs remarks in the Journal de Conchyliologie vol. I p. 205
»lexistence de lombilic est un caractere indifférent», and not of importance enough to

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. (ie

be of value as generic distinction. Equally unimportant is the character added by Dr
Koninck and WaaceEn that the shell is provided with longitudinal or spiral stria, which
cross the transverse ones. Carinaropsis Hatt Pal. N. York vol. I p. 183 consists of Ga-
stropoda belonging to different genera. Carin. carinata in all probability is a Bellerophon
of the large, compressed species, while C. patelliformis and C. orbiculatus are evidently
Patellid shells. Phragmostoma Hatt 14 Rept. N. York St. Cab. p. 94 is also likely to
be a broad, compressed Bellerophon. Waagenia Dr Konincx Ann. Soc. Géol. de Bel-
gique 1882 p. 14, is distinguished only by eallosities around the umbilical region.
HermMannsen in his Index’) has Vasulites as a synonym. of Bellerophon, but no such
generic name is found in the book cited”) by him. Monrrorr in his Conchyliologie sy-
stématique *) himself cites B. vasulites from Hist. Naturelle des Mollusques, though only
as a specific name.

Various efforts have been made by some authors to arrange the species of Bel-
lerophon in different groups. Dr Konick in his older work*) and Stacne’) both pro-
pose two series, one characterized by an elevated dorsal keel, the other by a sunk slit
band. But as it is evident, that generally in young specimens the slit band is sunk
and in older specimens of the same species becomes an elevated keel and when more-
over this change can be traced in the same specimen, this characteristic is not to be
maintained. Nor is it possible to apply the differences, which lie in an open or clo-
sed umbilicus as this character is changing in one and the same specimen. It seems to
be of more avail to group the different species, at least the Silurian ones, according to
the pattern of the ornamentation. A good characteristic of several species is found in
the size of the angle, in which the transverse striw join the slit band, as well the man-
ner in which they continue towards the sides. There is in very small specimens, of
B. latevittatus especially, a peculiar feature in a strong transverse groove (étranglement)
on the nucleus near the expanded apertural border. It reminds highly of what is seen
in the small individuals of the Goniatites. But as similar grooves or necks are seen
in other Gastropoda, as for inst. in Platyceras and Euomphalus, it needs not point to a
Cephalopodan affinity of the Bellerophons as some authors have thought. This trans-
verse sulcus is quite as deep in the middle of the shell as on the sides.

As to the geological history of this genus in Sweden, it may be remarked that
the oldest specimens are already present in the Inferior Gray Orthoceratite limestone
at Kongs Norrby, from where three different species have been found, and in the Superior
Red Orthoceratite Limestone at Skarpisen, both localities in Ostrogothia. Specimens
have also been collected in almost all Lower Silurian regions of Sweden as Oland and
Dalecarlia. I have not been able to identify with certainty a single species of the
Gotland Bellerophons with those from other Silurian strata, excepting B. trilobatus.
In the shale beds at Westergarn some few, badly preserved specimens have been found

1) Vol. ILgp. 677.
*) Denys-Montrort Hist. Nat. des Moll... . suite 4 I'Hist. N. de Buffon et Sonnini. Vol. IV p. 298.
3) Vol. [ p. 51. Bellerophon vasulites.
4) Anim. foss. de Belgique p. 338.
°) Jahrbuch der Geol. Reichsanstalt 1877, . 3, p. 297.
K. Sy. Vet. Akad. Handl. Bd. 19. Nzo 6. 10

74 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

of a species with considerably enlarged aperture and narrow whorls, representing the
division of Bellerophons named Phragmostoma, which are of such frequent occurrence
in the Upper Silurian shale beds of Scania. But they are too obscure for identification.

Conspectus of the Species:
I. Shell only with transverse striw, radiating in pinnate arrangement from the
slit band:
1 B. sphera n.
B. fasciatus n.
B. globulus n.
B. tenia n.
5 B. fastigiatus n.
6 B. tubulosus n.

Co bo

>

I]. Shell with longitudinal strix or furrows intersecting the transverse ones (=
Bucania WaaGen and Dr Konincx).
7 B. squamosus n.
8 B. Eiseni n.
9 B. elegantulus n.
10 B. latevittatus n.
11 B. gemma n.
12 B. pilula n.
Ill. Shell divided through two longitudinal grooves.
13 B. trilobatus Sow.

1. Bellerophon spheera n.
Pl. IIL figs. 35—38, pl. V figs. 1—16, pl. VII fig. 9.

Shell globular, extremely thin. Surface ornamented by closely set, transverse strix,
which abut upon the slit band in an acute angle of 45° and curve gently outward
in a bow, the convexity of which is directed towards the aperture. There is some
variation, as shown in the figures, with larger, smooth intervals between the strie.
Some faint longitudinal striw crossing them are visible in several specimens. In well
preserved shells and through sections in the umbilicus it is evident that many of the
transverse striw have continued as free, outwardly bent, thin laminze. They have been
especially crowded in the umbilicus, where they also are most completely preserved,
imbedded in the soft shale. Several figures are given on plate V, showing details in
natural size and magnified. Their length amounts to two millimeters and sometimes
more. Where they have been well protected they stand out in relief as narrow hooks.
These lamellae have probably, each in its turn, been the apertural border of the widely
expanded mouth.

The whorls are five and a half, much rounded, and, as seen in transverse sec-
tions, from two to three times as broad as high. The last whorl is much expanded near
the aperture, with the slit band elevated as a blunt keel. The aperture is large, trans-
versally obovate, the lips rather thick, the inner lip bent down as to hide the whorl

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. re
‘

on which it rests. The umbilicus is wide and open in the young specimens; in the
older it becomes by degrees more and more narrow, and is at last so concealed by
the large corners of the aperture and the interior lips, which have grown over it, that
only a little space is left open.

As far as may be judged by the direction of the lines of growth there has been
a deep and acuminate sinus in the outer lip. The slit band is comparatively narrow
and sunk between two faintly elevated lines and covered by distantiated crescent shaped
lines of growth. On the last whorl it changes into an elevated keel, on which every
trace of the crescent shaped lines of growth is effaced. The height of this keel some-
times amounts to more than one millimeter above the surface of the whorl.

The thickness of the shell is much variable, generally thin, excepting along the
interior corners of the aperture, where it covers the umbilicus and is several millime-
ters thick. The shell, in a thin section under the microscope, shows very thin, wavy
lamellx, through which clearer spaces or tubes vertically penetrate, pl. VII f. 9.

Colonies of a bryozoan, a Ceramopora, have often covered large specimens of this
shell with their luxuriant growth and in all probability destroyed the shell, which has
been dissolved, as only a cast of its surface is left on the calcareous basis of the Ce-
ramopora.

Largest diameter 96 millim., breadth of aperture 65 millim., height of the same
55 millim., diameter of umbilicus 15 millim.

This shell has been found very common in the lowest shale near Wisby, in the
superjacent limestone beds at Wisby and Martebo and also in the shale beds at Petesvik.

2. Bellerophon fasciatus n.
Pl. VI figs. 13—14.

Shell globular, the transverse striae of the surface are in regular distances, with
smooth, equal, band like interstices. They join the slit band in an angle of 66° and
then stand out from the band nearly horizontally. The slit band is sunk and narrow.
There are only three whorls visible, but probably they are at least four. The aper-
ture is cordate, the exterior or superior margin with an acute angle and the interior
one arched. Seen from the aperture the shell presents an obovate outline. The um-
bilicus is closed by a fold of the margin of the lowest apertural corner.

Of all the Gotland Bellerophons this is most nearly related to Bell. sphwra, but
differs through its obovate outline and the transverse strix. Height 25 millim., breadth
16 millim., height of aperture 10 millim., breadth 16 millim.

Only four specimens have been found in the middle limestone beds (b) and the
lowest part of c, near Wisby and Kyrkberget in Wisby.

3. Bellerophon globulus n.
Pl. V figs. 25—34.

Shell of somewhat variable form, globular, ovate or elliptical in outline, surface of a
dark, glossy hue, almost smooth, with extremely fine, densely packed transverse striz, which

76 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

join the slit band at an angle of 38°; they bend outwards towards the sides and again
converge towards the umbilicus. The slit band forms an elevated keel with a flat top,
on each side bordered by a fine line and wavy with the minute and delicate lines of
growth. Whorls four and a half, regularly increasing in width, twice as large as high
and consequently not so narrow as in Bell. sphwra. Shell thick and as common in
this genus, at thickest around the umbilicus and at the inferior corners of the aper-
ture. The last whorl, when seen from the side, is straight or only faintly curved, and
its apertural and dorsal contours are nearly parallel, f. 26. In my specimens, which
are not quite complete, the aperture is longer than the rest of the shell. The infe-
rior corners of the aperture near the umbilicus, where the shell is at thickest, are
rounded or cylindrical and completely hide the umbilicus, which in young specimens
is open. Diamet. 20 millims., breadth at the fragmentary aperture 17 millims., height
of the aperture 7 millim.

Occurs in the shale beds of Eksta at Djupvik and in Frojel. It is nearly related
to Bell. sphxera, but differs by having the umbilicus entirely covered by a fold of the
reflexed border of the aperture. The shell is moreover thicker and the direction of
the transverse striaw and their angle when joining the slit band quite different.

4. Bellerophon tezenia n.
Pl. VI figs. 22—25, pl. VII figs. 4—5.

Shell discoid with six much compressed and thin whorls, transverse, nearly el-
liptical in their section, twice as broad as high, their dorsal side only a little convex;
in many nearly flat, the lateral angles very thin and acute. All whorls are visible
on the umbilical as well as on the apical side. The only specimen which shows
some fragments of the expanded aperture makes it not clear whether there has
been an open or closed umbilicus, but it seems likely that it has been more narrow
than may be judged of by its wideness in the other samples. At the aperture, which
seems to have been quite as large as in Bell. sphwra, the shell attains its greatest
thickness and consists of several strata. On other parts, where fragments of it still
are seen, it is very thin. The transverse striw of the surface are nearly straight or
only faintly curved in an angle of 68° near the slit band. This band is narrow and
only a little elevated between two sharpedged lines. Height 60 millim., breadth of
aperture 60 millim., breadth of the last whorl near the aperture 28 millim., height 19
willim. Occurs in the lower limestone beds at Ostergarn and Ardre, and also on
the shore of Hammar in Kraklingbo, and in the soft gray limestone of Lindeklint and Fréjel.

5. Bellerophon fastigiatus n.
Pl. VI, figs. 1—10.

Shell rather more discoid than globular, aperture transverse and triangular in outline,
the base being only slightly arched. It is incomplete, the margins broken off and

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wn:o 6. be

fragmentary. Whorls five, transverse, carinated on the dorsal side. Umbilicus open and
large with steep borders. The transversal striaw of the surface crowded, joining the slit
band in an acute angle of 32°, they ure bent outwards and backwards to the umbilicus.
In several specimens there is an indistinct carina on both sides of the slit band and
parallel to it, placed at the point where the transverse stria are bending backwards.
The slit band is elevated, flat on its top, finely and transversally sculptured, somewhat
concave along its median line and bordered on cach side by two thinedged lines.

This species makes somehow an approach to the genus Cyrtolites by its acumi-
nated dorsal side, its wide umbilicus and its laterally compressed whorls. Height 14
millim., breadth 10 millim., diameter of umbilicus 4 millim., height of aperture 5
millim.

Several specimens have been found in the shale at Djupvik in Eksta.

From the shale beds of Djupvik in Eksta some specimens of Bellerophon lave
been found along with the former, the affinities and exterior characters of which have
been obscured through their bad conservation. But when sectioned they exhibit a pe-
culiar deviation from the other Bellerophons in being evidently asymetric or having the
whorls inclining nearer to the apical side, thus making an approach to a conical-spiral
volution. In this respect they coincide with the new genus Stachella, which Waacen
has instituted, and which chiefly is distinguished through its asymetric whorls. On
plate VI the figures 11, 12 give an idea of these shells.

6. Bellerophon tubulosus n.

Pl. XIX fig. 6B—11.

Shell globular or sphwroidal, with five whorls, thin, excepting around the umbi-
lical region. Surface ornamented with narrow, transverse stripes which meet the slit
band in an angle of 44°. They are elevated at their superior edge, the more so near
the umbilicus, where they also are more numerous. Parallel with this edge they are
finely striated. The slit band is narrow and the crescents of growth indistinct and
distantiated. The aperture is semicircular and its superior lip is slightly angular. The
lips are thin; their inferior side corners are prolonged in earlike lappets, curved like
hooks inwards against the very narrow umbilical opening without closing it. During
continued growth a tubular space is thus enclosed between the outside of the inferior
borders of the aperture and the hooklike, lateral prolongations of the shell. Where
they end they are, moreover, convoluted and directed backwards from the aperture. All
around these peculiar umbilical tubes the shelly matter has been deposited to an amount,
many times surpassing the thin shell on the dorsal side. In one ‘specimen, fig. 6, there
is a trace of a dark colour band around the covered umbilicus. H. 22 mill., breadth
16 mill.

A few specimens have been obtained from the superior limestone near Wisby at
Kalens qvarn and inside that town on Kyrkberget. As to shape and ornamentation
this species somewhat resembles Bb. fasciatus, though this is more angular on the su-

78 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

perior edge of the dorsal side aud has no tubes. As to these B. tubulosus comes near
to b. elegantulus where the enclosed spaces are more narrow.

7. Bellerophon squamosus n.
Pl. V figs. 17—24.

Shell globular, somewhat compressed, the last whorl much enlarged towards the
aperture. Whorls four, rapidly increasing in size, of elliptical section, the last one
subcordate with dorsal keel. Outlines of aperture nearly circular, deeply indented in
the midst of the exterior lip. Lateral and inferior borders smooth and gently curved.
Umbilicus open and only partially concealed through the inferior corners of the aper-
ture, which have grown down outside the same. The transverse lines of growth are
imbricated and project as irregularly curved lamellx, standing out much in relief with
their edges. These edges are extremely thin, as may be gathered from a section drawn
figs. 23—24, pl. V, and, moreover, much irregularly grown in many curvatures. At
the base they regularly join the slit band in an angle of 58°. The interstices are finely
striated by minute ornamental lines, parallel to the lines of growth and longitudinally
grooved. The spaces between the equidistant grooves are gently arched. Where the
grooves meet the transverse laminw, they are a little indented and hence form a wavy
line. The slit band is narrow, but distinct, situated between two elevated lines, so-
mewhat sinuous and more prominent on the last whorl than elsewhere. Height 45
millim., breadth and height of aperture 38 millim.

Found in several specimens at Lutterhorn and Lansa in Faré, Sandvik at Faré-
sund and on Kyrkberget in Wisby.

8. Bellerophon Hiseni n.

Ply Vil tigss 1924

Shell globular with enlarged aperture, as far as visible without laterally bent
margins. Sculpture of the shell very characteristic, consisting of some eight to ten
shallow, longitudinal grooves on both sides of the slit band and parallel with it, form-
ing, as it were, a broad median zone, occupying nearly a third of the dorsal surface.
On both sides of it there are no traces at all of any longitudinal sculpture. These
lines are crossed by fine and closely set transverse lines, which occupy the whole sur-
face and meet the slit band almost rectangularly, being only very slightly curved
towards the aperture. The umbilicus seems to have been open. The slit band which
is not well preserved has probably formed an elevated keel on the body whorl. Height
20 millim., breadth 36 millim., the umbilicus nearly 5 millim.

Only one fragmentary specimen was discovered by Dr G. Ersen in the hard cry-
stalline limestone at Wialmsudd near Farésund in the parish of Bunge.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 79

9. Bellerophon elegantulus n.

Pl. VI figs. 15—18.

Shell thick, globular, umbilicus closed by a convoluted thick fold of the inferior
apertural lip. A little above this fold, there is a transverse groove, partitioned off
from the aperture of the shell through a new fold or process which joins the inner
surface of the aperture. Exterior surface ornamented with regularly distantiated trans-
verse lines of growth, which meet the slit band in a very acute angle of 29°, then
Spread in an arched curve towards the sides. The interstices are densely and longi-
tudinaly wrinkled, as seen in the enlarged figures, giving the surface a finely cancellated
appearance. Slit band narrow and moderately elevated with rare, crescent formed
wavelets. Height 11 millims; width of aperture 12 millim., height of the same 7
millim.

One specimen has been obtained from the middle limestone bands near Wisby.

10. Bellerophon latevittatus n.

Pl. VI figs. 26—28, pl. VII figs. 6—8.

Shell globular, with expanded, transverse aperture. In the only specimen with
the shell preserved the height of the aperture is contained nearly four times in its
breadth. In casts of other specimens, which are almost entire, it is evident that the
exterior lip has been thin and enlarged. Some two millimeters further inside it is
provided with a thick transverse callosity or fold, which continues past the upper side
of the umbilicus, along the exterior sides of the aperture, where it disappears. This
callosity gives to the casts a strange appearance, in a certain way reminding of what
is seen in the young Goniatites. But the same kind of callosity also occurs amongst
other Gastropoda as for instance Platyceras cornutum. The interior or lower lip
of the aperture seems to have been divided in two lobes, as in young specimens of
the Carboniferous Bell. decussatus from Tournai. The umbilicus is open. The orna-
mentation of the surface consists of closely set, elevated, transverse lines, which meet the
slit band nearly rectangularly. They are closely and longitudinally wrinkled. The slit
band is relatively the largest, which any of the Gotlandic species is provided with, ex-
cepting B. gemma, being 1 millim. in breadth on a total diameter of the shell of
4 millim. It is elevated but flat. Height 7 miilims., breadth at umbilicus 6 millim., at
the aperture 10 mm., height of aperture 7 mm. .

Four specimens have been found in the lowest shale beds near Wisby and also
at Ostergarn.

This species comes near to Bell. latefasciatus SanpperGER, Verstein. des Rheini-
schen Schichtensystems, pl. 22 fig. 4.

Ss0 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

11. Bellerophon gemma n.

Pl. XIX fig. 12—14.

Shell globular, last whorl rather rapidly expanding, in section broadly transverse
or elliptical, inclining to crescent shape. The umbilicus is narrow and open. The
ornamentation, which cannot be plainly seen without a strong lens, consists of a large
slit band, covered by the same sort of densely crowded lines which decorate the sides
and join the slit band in an angle of 63°. They are longitudinally streaked with
elevated wrinkles, larger towards the opening and attenuated backwards. H. 5 mmn.,
breadth at the aperture 6 mm. Only a single specimen has hitherto been found in the
shales of Wisby. Another specimen in good preservation from the red limestone of
Sandarfve kulle comes near to the preceding, but differs in the slit band not being
elevated, only at the same level with the other surface, and also in the ornamental
lines being more arched.

12. Bellerophon pilula n.

Pl. VI figs. 29—30.

Shell globular, aperture, as far as preserved, transverse, crescent shaped, more than
four times as broad as high. Umbilicus open. Surface covered by a fine network of
minute, elevated, longitudinal and transverse lines, which enclose regular, quadratic
spaces. The slit band indistinct. Height 3 millim., breadth 2 millim,

Found in the oldest shale at Djupvik in Eksta.

13. Bellerophon trilobatus Sowersy p. p.
Pl. IV figs. 13—15.

Bellerophon trilobatus. 1839. Sowersy in Sil. Syst., 604, pl. 3 fig. 16.

1840. D’Orsieny H. Nat. Cephalop., 209, pl. 7 fig. 24—27. PI. 8 figs. 13 is also
cited, but in the copy of the work, to whieh I have had access there is no
plate 8. Perhaps it has never been published.

1850. D’Ors. Prodr. I, 31.

1854. Morris Cat. Brit. Foss., 288.

1855. Mac Coy Brit. Pal. Foss., 311.

1856. Sanpspereer Verstein. des Rhein. Schichtensyst., 177, pl. 22 f., 1—3.

1867. Sauer Siluria 3d Ed, 534, pl. 34 f. 9.

1873. Ip. Catal. Cambr. Museum, 97, 192.

Shell involute, with three or four broadly and transversally flattened whorls,
which are elliptical in section, and their height contained nearly three times in
their breadth. The dorsal surface is divided in three different longitudinal fields
through two deep grooves near the sides. The median field is at least of double the
size of the lateral ones. As the specimens exist only in casts, there are no vestiges
of the shell itself and it is even doubtful whether it really belongs to this genus as

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. n:o 6. $1

never any trace of the slit band has been found. Of the three varieties which
SANDBERGER (1. c.) has described, his B. tumidus comes most near to the Gotlandic
form. As to the shape it also agrees with the figure given by Sowersy in Silurian
System, although it is larger than his. The figure given by D’Orsieny is altogether
different. Bucania trilobata Conrap ') may also belong to this species. Largest dia-
meter 18 millim., breadth of aperture 22 mm.; height of aperture 9 millim., diameter
of umbilicus 3 mm,

It occurs in the shales of Petesvik in Habblingbo and of Wisby and in the oolite
and sandstone of Bursvik.

Gen. CYRTOLITES Conran.

Synonyms. 1838. Cyrtolites Conrad Ann. Rep. N. Y. Cab., 118.
1838. Phragmolithes Conrap p. p. ibid., 119.
21839. Ditaropus Ravinesavet Bull. Soc. Géol. de France, vol. X, 378.
1845. Microceras Haut Sillim. Journ., vol. 48, 294.
1866. Tropidiseus Menx Proceed. Chicago Acad. Sci., vol. 1, 9.
1880. Tropidodiscus WAaGEN (emendatio) Palaont. Indica XIII, 131.
1882. Tropidocyclus Dr Kontnex Ann. Soc. Géol. de Belgique IX, 12.

Shell discoid, laterally compressed, involute or with free, not contiguous whorls, um-
bilicus open and double, aperture elongate and lanceolate. A dorsal keel originates from
a sinus or slit in the superior border of the aperture and continues more or less elevated,
the interior lip having its form moulded according to the whorl on which it rests.

In spite of all what has been stated”) to the contrary, there can be no doubt,
nor mistake about the type species of this genus and what its first authors meant
thereby. This type is C. ornatus, first named and shortly described by Conran in the
Annual Report of the Geol. Survey of New York 1838 p. 118 and then again more in
full described and figured by Hatt in Palwxontology of N. York vol. I p. 308 pl. 84
f. 1. There has been almost no dissension amongst the American authors as to this
genus. It is of no avail that both Conrap and Hat a few years later united with
the first species other fossils, which are no Gastropoda at all, being in reality Cephalo-
poda, probably Cyrtocerata.*) The first described type must here, as always in similar
cases, be the guiding one, around which to group related species and from which dis-
similar ones are to be discarded. The other coéval genus, Phragmolithes of Conran,
also coincides with Cyrtolites, as has been shown by Hatx in Pal. of N. York vol. I.
p- 188, and in which some lines of growth had been interpreted as septa. Ditaxropus
of RariNesQuE is a most obscure fossil, but may possibly be only a form of Cyrtolites.
Microceras Haut. is doubtingly described as septate, but Merk has in Pal. of Ohio vol.

') Haut Pal. N. York, vol. 2 p. 13, 98. — Planorbis trilobatus Geol. Rep. N. Y., 1838 p. 113.

2) De Konryek Faune Carbonif. I, tv, p. 293. — Waaacen Paleont. Indica, Salt Range Foss. p. 132.
3) Conrav Journal. Acad. N. Se. Philadelphia vol. S p. 270 (C. trentonensis). Hann Pal. of N. Y. I,
p. 188.

K. Sy. Vet.-Akad. Handl. Ba. 19, Nio 6. 11

82 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

1 p. 147 shown that it in no essential characters differs from Cyrtolites. Tropidiscus
Meek, or Tropidodiscus as the name has been emendated by WaaGeEn, is one of those
forms in which the whorls are more numerous and involute than the others and the
dorsal carina thin. As the name had already been preoccupied for a recent shell of
the Planorbide, Dr Konrnox has instead proposed Tropidocyclus, but this as well as
the former ones must be regarded only as synonyms to Cyrtolites. Porcellia Verneuili
D’Ors., Dr Kon. Faune Carbonifere, IH, pt IV, 288, belongs probably also to the genus
Cyrtolites.

There is some difference as to the involution and number of the whorls, and as
to the size and sculpture of the dorsal carina. But the common compressed, discoid,
shape and the form of the aperture, which as to its details is nearly alike in all, are
sufficient grounds to unite them in the same genus.

The geological range of its species is limited in Sweden to the Upper Silurian
formation of Gotland from where five species are known in the shale and sandstone
beds, and three in the superjacent limestone, one species being common to both. Abroad
Cyrtolites continued as far as now is known in both the Devonian and Carboniferous
formations. In North America several species are found already in the Lower Silurian.

Conspectus of the species:

I. Whorls free or scarcely contiguous, few in number.

1. ©. lamellifer n.
2. (C. pharetra n.
I. Shell with contiguous whorls, numerous, disciform.
3. C. arrosus n.
4. (©. obliquus n.
5. (C. euryomphalus n.
C. discus n.
7. ©. orbiculus n.

1. Cyrtolites lamellifer n.

Pl. VI figs. 31—38.

Shell laterally compressed, along the median line of the sides somewhat tumid
and thence elliptic in a transverse section. The surface is transversally ridged by a
succession of regularly distantiated, outstanding lamella, wide apart at the dorsal side,
converging towards the ventral side and most of them meeting. They stand out,
slightly bent against the aperture of the shell (figs. 34, 37), looking like hooks when
seen edgewise. They are about fifteen and represent the successive apertural borders.
They are crossed by regular, elevated longitudinal striea nearly of equal size, separated
by interspaces of the same width. Rectangularly to them, minute threadfine ornamental
lines are running. The dorsal keel or the slit band is moderately elevated and in
direct’ continuation of a deep tongue shaped slit in the middle of the superior lip of
the aperture. The slit| band is even and consists of small arched lines (figs. 32, 38),

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wn:o 6. 83

with their curves directed backwards. A great many of them are direct continuations
of the lateral, projecting lamellae, which thus run without interruption all around the
shell. The whorls are in the most perfect specimens two and a half, open, disjointed.
In some, as that delineated in figure 54, there is only one and a half whorls, the shell
resembling a Cyrtoceras. The aperture is elliptical, acuminated towards the dorsal and
ventral sides. The middle of the inferior lip is elevated into a small, vaulted saddle.
It does not, however, repose on the back of the preceding whorl as in the other spe-
cies. On the ventral side of the shell quite opposite to the slit band, there is a shallow
groove running down towards the apex. Diameter of the aperture 20 millim. in the
fragment of a very large specimen. A complete specimen is 11 millim. at the aper-
ture, the transverse diam. of the aperture is 6 millim., total length 18 millim.

This beautiful shell has been found in several specimens in the limestone beds
(b) in the neighbourhood of Wisby and towards the north as far as Likkershamn.

2. Cyrtolites pharetra n.

Pl. VI figs. 39—51.

Shell discoid, compressed, tumid along the middle line of the sides. The orna-
mentation consists in straight, equally distantiated sulci with blunt edges, but in an
obtuse angle, directed forwards, near the back; they give to the surface an imbricated
appearance and they converge towards the ventral side. They continue without inter-
ruption around the shell, forming at the dorsal carina a sinus backwards and down-
wards. The spaces between the sulci are smooth or slightly striated by fine, longitu-
dinal lines. There are traces of longitudinal colour bands, alternately dark and light
of unequal largeness, as represented in fig. 39. The whorls are two and a half, free
and disjointed, rapidly increasing in width (fig. 45). The dorsal carina is low, almost
vanishing near the aperture, gradually increasing in height backwards and also becom-
ing more narrow. The aperture is ovate or in some approaching to circular, its in-
terior lip reclines on the back of the nearest whorl and is, at the point of contact,
bent in a small saddle. Corresponding to this a groove runs on the outside of the shell
to the apex. The slit in the superior lip is shallow and broad. Length 15 millim.,
longest diam. of the aperture 9 millim., transverse diam. 6 millim.

Only found in the shale at Djupvik in Eksta from where several specimens are
preserved in the State Museum at Stockholm.

3. Cyrtolites arrosus n.
Pl. VI figs. 52—53.
Shell discoid, tumid, involute, whorls three and a half, rapidly increasing in

size. Surface with fine, transverse, regularly curved lamellar lines, with serrulated
edges, as shown in fig. 53. The aperture is oval, the slit seems to have been deep

84 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

and the saddle of the interior lip is large. The keel is blunt to judge by the cast
of it. Height of the shell 33 millim., breadth 23 millim. Height of aperture 20 mil-
lim., breadth of same 15 millim.

Only one specimen has hitherto been found in the limestone of Martebo.

4. Cyrtolites obliquus n.
Pl. VI figs. 54—55.

Shell discoid, a little obliquely involute, terete; ornamental striz most minute,
closely set, with denticulated edges, dorsal carina blunt and narrow. Whorls three and
a half. Diameter of the fragmentary shell 3 millims. From the sandstone of Bursvik.

5. Cyrtolites euryomphalus n.
Pl. VII figs. 10—15.

Shell discoid, involute, surface smooth, rather glossy, ornamented with regularly
distautiated lines, elevated, giving the surface an imbricated appearance. Along the
interior edge of the whorls there runs a narrow ridge, on which the transverse lines
swell in a minute nodule. From this ridge the surface falls off abruptedly towards
the centre of the shell. The whorls are four and a half, gradually increasing in width,
contiguous. The aperture is broader than long, nearly pentagonal, with the dorsal ca-
rina forming a tonguelike processus from the superior edge. The slit band is much
prominent, flat on its outer edge and covered with distantiated, crescent shaped lines
of growth. Diameter 5 millim., breadth of aperture 3 millim.; height 2 millim.; dia-
meter of space enclosed within fhe interior ridge 2 millim. From the shale at Djup-
vik in Eksta. Some twenty specimens known. <A corroded specimen has also been obtained
from the sandstone of Bursvik.

6. Cyrtolites discus n.
Pl. VII figs. 18—21.

Shell discoid or lenticular, slightly tumid, surface with linear, elevated, trans-
verse striw, curved gently backwards on the dorsal side, regularly distantiated and hav-
ing between them much finer, minute lines. Whorls four, gradually increasing, the
last one partially free. Aperture triangular, lower lip nearly straight, horizontal, lateral
margins faintly curved, converging at the narrow dorsal slit. Slit band narrow, eleva-
ted, blunt, not much prominent, covered with small crescent shaped lines of growth.

Largest diameter 7 millim., breadth 3 millim.

The original specimen, which belongs to the Museum of the Geological Survey
of Sweden, has been found in the sandstone of Bursvik. Later, another specimen has
been found in the middle limestone beds near Wisby. This is more smooth without
any smaller lines between the large transverse striz.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. Nn:o 6. 85

It is distinguished from the following through its fewer and broader whorls,
through its lower and blunt slit band and its triangular aperture.

7. Cyrtolites orbiculus n.
Pl. VII figs. 16—17.

Shell discoid, imvolute with all whorls contiguous. Surface with distantiated,
threadfine, elevated, transverse lines, gently curved backwards, the interstices being
smooth or indistinctly finely striated. The whorls are five and a half, at highest near
their inner edge, which sinks vertically to the deep suture. Aperture broadly lanceo-
late. Slit band a thin, prominent keel more elevated than in any other Gotland spe-
cies of this genus.

Largest diameter 13 millim; thickness 4 millim. at the aperture. Only one spe-
cimen has hitherto been found in the shale of Djupvik in [ksta.

Gen. TREMANOTUS Hatt.

1864 Tremanotus Hat Extract of 18th Rept. St. Cab. N. York p. 45.
1868 Gyrotrema Barranvé, according to BiesBy Thes. Silur. p. 167 and also to letters from M. Barranve
himself.

Shell discoid, involute, whorls tumid, visible both from the umbilical and apical side,
consequently with large, open, double umbilicus; aperture with greatly expanded and enlarged
lips, the slit very shallow, continuing in a narrow keel, which is perforated by a number
of oval apertures. These have subsequently been closed with shelly matter.

This genus was founded by James Hatt, as is stated by Merk’), in an Extract
from the 18th Report of Regents N. York. St. Cab. p. 438, which was issued in 1864,
but this extract was never published along with the rest of the 18th Report”), being
only in 1868 joined to the first edition of the 20th Report, with the date 1865 printed
on the sheet wherein the said description is contained. It seems, however, not to be
any valid grounds to follow Hatt in placing it as a subgenus to Porcellia, a genus
which belongs to a much later period and has a deep slit in the exterior lip and a
slit band quite as in Pleurotomaria, but without apertures and, moreover, obliquely spi-
ral. Tremanotus is indeed quite as much different from this genus as from all other
Bellerophontid, excepting Tubina and possibly also Salpingostoma, in the presence of
the apertures on the dorsal keel. It resembles, as to the expanded aperture, some of
the species of Bucania, which genus, as it has been limited by its founder Haux in
the Pal. of N. York vol. I, contains many heterogenous forms, of which several ones
are extant only in obscure casts. Amongst other genera, Tubina Barranve’) is related

1) Meek Proc. Chicago Ac. Se. 1865, vol. I. p. 10.
*) Issued in 1865.
3) Owen Palzontology 1860 p. 71 fig. 71, 8 and also named thus on labels in collections sent from Prag.

86 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

through the rows of apertures along the back and the sides, which, however, are prolonged
into curved, spine like tubes. It seems also that Salpingostoma Frerp. Roumer, Leth.
Geogn., Ed. 1876, Taf. 5 fig. 12, is related through its enlarged aperture and an elon-
gated slit on the back of the last whorl. S. A. Mirier in his Supplement to the Ca-
talogue of American Palwozoic Fossils p. 304, says that »Tremanotus is a synonym for
Bucania. The supposed openings on the cast represent the spines upon the back of
the anterior part of the last whorl of the shell. But this cannot be the case, as the
smallest specimens already are provided with these apertures, which during the conti-
nued growth of the shell become hidden under the overlying whorls. There are no
signs that the borders of the apertures have been formed through spines or tubes ha-
ving been broken from them, they are even and smooth and resemble nothing more
than those seen in the recent Haliotis. The peculiar ornamentation of longitudinal,
coarse lines also augments the probability that both are nearly related to each other.
This must, however, be left as an open question as there are no connecting links, the
Tremanoti disappearing with the Silurian era and Haliotis at the earliest found in the
Miocene strata.

This genus first appears in the Lower Silurian strata of Oland from the Chas-
mops limestone of which island, at Boda, the Swedish State Museum possesses fragments
of a Tremanotus closely related to Tr. longitudinalis, if not identical. :

In the strata of Gotland two species occur:

1. Tr. longitudinalis with whorls of circular section;

2. Tr. compressus with whorls of elliptical section.

1. Tremanotus longitudinalis n.

Pl. III f. 39, 40, pl. IV f. 1—7.

Syn.: Bellerophon dilatatus 1867. Lrxpsrrom (nec Sow.) Nomina fossil. Gotlandiw p. 23. It may be that
this species is identical with Sowersy’s B. dilatatus Sow. Sil. Syst. p.
627 pl. XII figs. 23, 24. According to M’Coys more elaborate descrip-
tion in Palweoz. Fossils p. 309 this species has spiral lines, but as in
neither work any mention is made of apertures on the dorsal keel, I
cannot refer my specimens to the English ones.

Shell thin, discoid, whorls four, visible on both sides, evenly rounded, cylin-
drical and of circular outline in transverse section. Aperture considerably enlarged,
with anterior or outer lip turned up as seen in fig. 3 pl. IV, without any slit, only
with a shallow indenture from which a small groove continues on the inside. Where
fragments are left of the inner stratum of the shell, as at the inner lip of fig. 1 pl.
IV it is smooth with only faint striw and the lip is so much reflexed that it covers
more than two thirds of the whorl on which it reclines. As this interior stratum
often has been destroyed, there is on the aperture commonly only seen the impression
of the outer side. The radiating strix all arround the aperture, seen in the same
figure 1, are impressions of the exterior surface which have been uncovered. The inner-
most opening in the middle of the apertural expansion is transverse or somewhat tri-
angularly cordate, pointed towards the outer lip and broad on the opposite side. The

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 87

outer side is ornamented by longitudinal, elevated bands, of unequal size, large and
narrow, as it were, in pairs with larger interspaces. They are not quite parallel with
the median axis and spreading toward the aperture in a sort of pinnate arrangement,
new ones being intercalated from the dorsal keel. These bands are interrupted by
transverse, sinuose, sunk lines, in older and worn specimens much reminding of the
fringed sutural lines of the diaphragms of the Ammonites. As seen in figs. 4 and 6 pl.
IV these interruptions are very evident along the transverse lines and it is indeed a
new set of longitudinal bands which starts in the front of such transversals. These
are, as may clearly be seen through fig. 39 pl. HI, the edges of the old expanded
apertures, which in perfect and intact specimens must have projected as imbricated
lamella, the one beyond the other, as in some of the Cyrtolites.

Along the median line of the dorsal side an elevated, narrow keel is stretching,
corresponding with the groove on the inside; at some distance from the superior margin
of the outer lip there is a row of clongated, elliptical apertures with elevated borders.
These apertures continue for a while open and become further down on the spire closed
with shelly matter as in Haliotis.

Longitudinal axis of aperture 94 millim., transverse diam. of same 95 millim.,
diameter of last whorl near the aperture 3] millim. Distance from the edge of the
outer lip to the opposite end of the whorl 115 millim.

This, one of the largest of our Silurian shells, has been found in many places on
Gotland. In the oldest shale beds from Halls huk, along the shores north and south
of Wisby, in the shale of Djupvik in Eksta, Petesvik in Habblingbo and further inland
in the shales of Wisne myr in Fardhem, and also in the sandstone of Bursvik. The
superjacent limestone and oolite beds also contain it. It has been found in these
beds at the canal near Westdés in Hall, in Martebo, around Wisby, in a section near
Stjernarfve in Eksta, in the limestone near Lau church and the oolite of Bursvik. From
the uppermost limestone strata it has been obtained at Lutterhorn in Faré, Martebo,
Kalens qvarn near Wisby, the upper limestone of Slite, Wialmsudd at Farésund and at
Fréjelklint. It occurs almost always in casts, only a few specimens having been found
with the shell, which is very thin.

Among nearly related species Treman. trigonostoma Hatt and Wnhirrieip Geol.
Surv. Ohio, vol. II p. 146, pl. VIII f. 5 resembles Tr. longitudinalis in a high degree.

2. Tremanotus compressus n.

Pl DV fies. S—12.

Shell discoid, involute, whorls five, transverse with the lateral diameter largest.
In a section the whorls are of an elliptical outline. In the nuclei, which have been
found, nothing is left of the expanded aperture. There are faint traces of longitudi-
nal lines. The apertures on the dorsal keel are smaller, more regular and closer sct
than in the preceding species, elliptical or ovate. Largest diameter 34 millim. Breadth

88 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

of largest whorl at the aperture 32 millim. Height of the same 18 millim. Occurs
in the limestone beds of Ostergarn, but only as nuclei, also at Hammaren in Kriklingbo.

Amongst formerly known species, Bellerophon Aymestrensis Sow. Sil. syst. p.
616, pl. 6 fig. 12 seems to be nearest related to this species, but there are no apertures
on its back, as far as the evidence goes.

Fam. VI. PLEUROTOMARIDZ’ D’Orpieny.

Since Daur in the Bulletin of the Museum of Comparative Zoology, vol. IX, Aé@ 2
(1881) p. 77 and following, made known the results of his researches on the structure of
the animals of two different species of Pleurotomaria, dredged up from the depths of
the Mexican Gulf there are more valid grounds than before to attribute to the members
of that large genus an independent position in a family of their own. Scissurella which
had long been considered as the only living representative of the Pleurotomarida,
must henceforth be separated from them and receive its place with the Trochidw, while
Pleurotomaria, according to Dati »stands nearest the Trochidw, with features recalling
the Haliotida». This same opinion had indeed also been pronounced by some other
zoologists previous to Dati’s researches on the animals themselves, as by Craus, though
he includes Scissurella in this group.

It is, however, very difficult, on various grounds, to draw the exact limits in
respect to several of the palawozoic forms and to tell with certainty, which are belon-
ging to this family and which are not. It must be borne in mind that there are se~
veral shells, besides the Pleurotomariw and belonging to quite different families, which
are provided with a slit in the exterior lip and a slit band, as nearly as possible re-
sembling that of Pleurotomaria. Scissurella, for inst., is provided with a similar band
and also Emarginula, in both of which the organization of the animals is different from
that of Pleurotomaria. In the Bellerophontide there also occurs a slit band, which in
many of them, though not in all species, is formed upon the same plan as in Pleuro-
tomaria.

The peculiarity in the structure of the body, which has caused the deep slit,
may, no doubt, be shared by several other Gastropoda, else dissimilar, but in them
originating only a shallow notch, as sometimes, not typical, in certain specimens of
Platyceras or typical in all species of several genera, as in the next family, the Euom-
phalide or in the large genus Pleurotoma or in Siliquaria. In none of these, however,
the peculiar slit band is marked by distinct crescent-formed lines of growth or la-
melle, sometimes attaining an enormous development and enclosed within two or even
more distinct elevated lines or lamelle.

The nacreous shell of the true Pleurotomariz is still preserved in a great ma-
jority of the Silurian species which are described further on. There must rest some
doubt concerning those, in which the nacre is not left behind, but which else in all
details are like the Pleurotomaridse and which, provisionally at least, may be included
in this family.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. Nn:o 6. 89

According to the definition first given by Dr France all those palwozoic species,
which have the characteristic, broad slit which by and by during continued growth is
filled up and changed into the equally characteristic slit band, are numbered amongst
them. This family is thus made to contain the following eight palwozoic genera, viz.
Pleurotomaria, Murchisonia, Odontomaria, Brilonella, Porepliva: Catantostoma, Polytre-
maria and Trochotomaria. Of these only two, Pleurotomaria and Miichivonta’ are re-
presented through species in the Silurian formation of Gotland, but in such a large
number that they make up nearly a third of the whole fauna of Gastropoda.

The limits between this family and the following, that of the Euomphalide,
are somewhat obscured through such forms as Pleuronotus (Euomph.) Decewi, in which
there is an approach to the formation of a complete slit band, in connection with a
general form of the shell as in Euomphalus. It is although questionable whether one
of the specimens’) figured by James Hatt and in which the slit band is most promi-
nent really belongs to the same species or to Euomphalus at all.

There are also some shells which have been placed in this family, though they
sometimes exhibit a change of a regular and distinct slit band into the simple, notched,
angulate rib, such as is characteristic of the Euomphali. Pleurotom. planorbis His.
for instance thus forms in a certain degree a connecting link between both families.
But in consequence of such structural variations some confusion has been unavoidable
and some uncertainty ensued which genera are to belong to this or the following fa-
mily. Moreover, genera, which do not at all show the characteristic features, have
been placed amongst the Pleurotomaride, and, again, others, which of necessity must
be numbered with them have been excluded. An attempt to clear up this somehow
is made further down, when the respective genera are treated.

Gen. PLEUROTOMARIA De France.

1810? Hercoles Montrort p. p. Conchyl. System. IH, 274.

1810 Anatomus Monte. p. p. ibid. 278.

1821 Pleurotomaria De France in Frrussac Tableaux Systématiques, p. XXXIV.
1823 Seissurella D’OrBtany p. p. Mém. Soc. H. N. Par. vol. 1, 340.

1825 Pleurotomarium BULAINVILLE Malacologie, 429.

1837 Inachus His. p. p. Leth. Sueec., 37.

1857 Ptychomphalus LL. AGassiz Gross-Britanniens Mineral. Conch. 23, 222.

1842 Scalites Conrad p. p. in EmmMon’s Geol. Rept. 312.

1847 Rhaphistoma Haut Pal. N.-York I, 28.

1859 //elicotoma Saurer Figures and Deseript. of Canadian Organic Remains, Dee. 1, 10.
1876 Huomphalopterus Pero. Rormer Leth. Geogn. Ed. 4. 1:e Theil, Taf. 14 fig. 9.
1883 Gosseletia De Koninck Faune Carbonif. Belg. II, pt. 4, 28.

1885 Agnesia In. Ibid. 99.

1885 Luciella Ip. Ibid. 107.

1883 Mourlonia Ip. Ibid. 245.

Shell of varying shape, trochiform, turbinated, discoid ov globular, with a broad
angular slit near the middle of the exterior lip, continued on the whorls hy a band, which
is bordered by one or two elevated lines on each side and towards which the trans-

1) Pal. of N.-York, vol. V, pt. De ply 29eho 7:
K. Vet. Akad. Handl. Band 19. Nio 6. 12

9O G. LINDTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

verse stria@ of the wpper and lower moiety of the whorls converge in direction backwards.
In most well preserved specimens the shell is nacreous. In some species there is a tendency
to fill up the apex of the shell with solid calcareous matter or even to partition off the
apex by imperforated tabula or diaphragms.

Rich as this genus is in a great number of variously formed’ species, ranging
in time from the basis of the Lower Silurians through all the Paleozoic formations
with well nigh 500 species, it is conceivable, that many attempts have been made to
divide and subdivide it in generic groups of a second order or even only in divisions
of wider or more narrow circumscription. Before attempting to make any such divi-
sions for the Gotlandic species, it may be convenient to take a review of older grou-
pings or of genera which may be considered as synonymic.

As to the claims of Dre France as the first author of Pleurotomaria, it cannot
any longer, as Dani thinks, be doubted that De France really must be regarded as
the author and by almost unanimous consent also has been acknowledged as such.
Dai again (Preliminary Rept. on the Mollusca, Bullet. Mus. Comp. Zool. Vol. IX n:o 2
p- 78) considers, that Sowersy who was the first to publish its characters, is the real
author and that his name has to replace that of Dr France. But the case stands as
follows. The name Pleurotomaria is printed for the first time in Farussac’s Tableaux
Systématiques '), earlier than June 1821 and in December the same year it was characteri-
zed by Sowersy in his Mineral Conchology vol. III p. 139, pl. 278. In 1823 Frrussac
in a Note to the Memoir of D’Orpiany on Seissurella in the »Mémoires de la Soe. d’Hist.
Nat. de Paris», vol. I p. 340, says on Pleurotomaria that »ce genre est connu depuis
longtemps des Naturalistes de Paris et son nom est déja imprimé dans plusieurs ouvrages».
ile does not name any body else but De France as the author. Moreover, JAMES
Sowersy himself before 1825, when the last pages of his »Genera of Recent and Fossil
Shells» were published, in the descriptive letterpress to pl. 205, where Pleurotomaria
is figured, expressly states that he considered Dr France as the author, in saying »the
Pleurotomaria of Dr France», never mentioning himself as the author or making any
claims as such and even not referring to his own previous description in the Mineral
Conchology.

Prominent amongst the synonymic genera is Ptychomphalus L. Acassiz founded
on a shell from the Mountain Limestone, Helicina compressa Sow. It should deviate
from the others in the possession of a callosity on the umbilical centre. But Dr
Koninck in his last work on the Carboniferous Fauna of Belgium includes in Ptychom-
phalus the majority of the Belgian Pleurotomarix of that period, 59 species, and does
not accept the genus Pleurotomaria at all, on the ground that the first species de-
scribed by Dr France have a wide umbilicus. Now the absence or presence of an
umbilicus cannot, as Drsnayrs”) long ago has remarked, have any influence on the

") Tableaux Systématiques des Animaux Mollusques classés en familles naturelles, p. XXXIV. The second
part of this work, »Tableau Systématique de la Famille des Limaces» bears on its title page the date
»Juin 1821», The preceding pages i—xlvij, where Pleurotomaria is catalogued, are, consequently,
still older.

2) Journal de Conchyliologie I p. 209.

KONGL. SV. VET. AKADEMIENS HANDL BAND. !9. w:o 6. 91

creation of new genera, when it is known how this character varies in one and the
same species and that, moreover, a single character seldom is so important as to
distinguish a genus. Amongst the species of Ptychomphalus, established by Dy Koninck
there are several without any callosity at all, and also others where a narrow umbili-
cus is seen. Of the other new genera, ranked by Dr Kontncx with the Pleurotomaride,
such genera as Baylea, Worthenia, Rhineoderma do not show the least trace of any
slit band to judge from the figures, the descriptions and in some instances by such
specimens of them as I have seen. The genus Agnesia again seems to have been
founded only on the distinction of its being sinistral, but as it in other details agrees
with Pleurotomaria and _ sinistral as well as dextral specimens occur within the same
species of Pleurotomaria, as, for inst., Pl. decussata Sanppercer (Versteiner. d. Rhei-
nischen Schichtensystems p. 197, tab. 24 f. 2), there seems not to be valid grounds
to create a new genus out of it. The same may be said in reference to Gosseletia ‘),
Mourlonia and Luciella as none of them has such prominent or permanent characters
as to entitle them to any generic distinction from Pleurotomaria.

Ferp. Rormer’s Euomphalopterus, however aberrant, is nothing but an extreme
form of Pleurotomaria, as will be shown further down. The extraordinary develop-
ment of the slit band is shared by some species which have hitherto been placed
within the incongruous genus Eccyliomphalus, as for inst. Ecc. alatus Ferp. Roemer:
His Odontomaria, Leth. geogn. 4:th Ed. 1 Th. Taf. 29 fig. 10, of which he says that
it »begreift gewissermassen abgerollte Pleurotomariem, is, as it, however, must be
conceded, more straight than any other. As further instances of such Pleurotomaridx
may also be cited Pleurotomaria centrifuga F. Ap. Rormer, Verstein. des Harzgebirges
p. 22, Taf. VII fig. 11°). But, as Ferp. Roemer himself lone ago remarked *), the forma-
tion of scalarid shells can only have a subordinate value as a generic characteristic,
as there are involute or evolute specimens belonging to the same species as we shall
see in the description of Pleurotomaria qualteriata. The same peculiarity in the
growth of the shell occurs also, as is already shown, in Platyceras and even in Euom-
phalus, without there being any grounds to ascribe to it specific, so much the less
any generic value.

The genera Scalites, Rhaphistoma and Helicotoma are founded chiefly on American
fossils and belong to the group of Pl. qualteriata, having the whorls on the apical
side more or less flat and even; the slit band situated on the acute outstanding angle,
which is formed where the apical and the umbilical sides meet. Most authors seem
now to agree that all are identical and coincide with Pleurotomaria.

') This name has already been employed by Cu. Barrois in 1881 for a lamellibranchiate; Ann. Soc. Géol.
du Nord, VIII, p. 176.

) Pleurotomaria extensa Herpenuain Graptolithfiithrende Diluy. p. 18, Taf. 1 f. 10 (= Bellerophon evo-
lutus Haupr Taf. III f. 13) is perhaps only an Euomphalus.

%) Lethaa geognostica, Ed. 3, vol. 1, p- 455. »Es kann jedoch jener Umstand wohl kaum zur Aufstellung
einer eigenen Gattung geniigen, da sehr verschiedene Gasteropoden-Gattungen (z. B. auch Helix) deren
Umginge regelmassig verbunden sind, ausnahmsweise zuweilen in Folge noch nicht niher erforschter
Kinwirkungen frei werden. In keinem Falle diirfen solehe Arten von Euomphalus getrennt werden,
bei welchen jene Trennung der Umgiinge nicht stets, sondern nur vorherrschend sich findet.»

92. G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Besides the above enumerated genera, which have been exclusively, or almost
so, instituted for the reception of species of Pleurotomaria, other genera, which have
uothing in common with that genus, shelter a few true Pleurotomariw, but have not
been placed in the list of synonyms, as their authors did not intend them for Pleuro-
tomarix. So, for inst. Pleurotomaria elliptica His. has been by Dre Koninck included
in the Trochoid genus Flemingia, established by him, but such instances are mentioned
further down in the descriptions and synonyms of the species,

It must be conceded that the limits between this genus and Murchisonia are very
difficult, to draw, a wide field being given to arbitrary individual opinions through the
vagueness attributed to the chief character of Murchisonia, viz. the length of its spire.
It may, nevertheless be practically useful to distinguish such Pleurotomarix, which have
a long, slender spire of more than six, beadlike whorls (= Hormotoma Saurer) as
Murchisonia. In them the nacreous nature of the shell is not so evident as in Pleuro-
tomaria proper. The nature of the Pleurotomarian shell as nacreous has been much
contested, but it admits of no doubt through several Gotlandic specimens, which still
retain the pearly coating interiorly.

The character of the slit in the Silurian specics is rather deviating from what
commonly is represented as its form in secondary and more recent formations. The
lips are in these straight cut and the borders of the slit parallel, but in the Silurian
ones the slit forms an acute angle and the borders are diverging. In some the slit is
linear, as in Peurotom. wxquilatera. As to the slit band, one of the most characteri-
stic features in this genus, it deserves more than a passing attention. It is in almost
all instances hemmed in by at least two, parallel, elevated lines, one to each side, al-
ways distinct. The band itself is of a varying breadth, linear as in Pleur. gradata, pl.
VU, fig. 26, or large, relatively, as in Pleurotomaria exquisita, pl. XI fig. 3. The usual
ornamentation consists in crescent-formed lines of growth, pl. LX, figs. 2, 4, 6, 15 ete.,
with the concavity towards the aperture. These crescents are sometimes crossed by
longitudinal lines as in Pl. claustrata pl. VII f. 31, 34, Pl. glandiformis, PI. biformis,
pl. VII f. 42 or by a longitudinal ridge as in a whole group of Pleurotomaria with
Pl. bicincta pl. VIII figs. 19, 21, 22, 23 as their type. In Pl. limata, pl. X figs. 14—
16, the lamellae of growth have a most extraordinary appearance being thin, prominent,
bent forward, imbricated and in their midst divided through an ovate indenture. The
bordering lines are either very low, of middling size or developed to an enormous
length as lamella. There can be discerned certain gradations, by which the extreme
development in PI. alata is connected with the others. In Pl. claustrata, pl. VU
f. 32, both the bordering lines project so much as to transform the slit band into a
deep groove around the shell. In PI. limata, pl. X fig. 8, 14, they stand forth and
form a sharp keel around the shell. A magnified section of it is represented in pl. X
fig. 14, being included in soft limestone, whereby the most delicate parts are preserved.
The cusps inside are sections of the crescentic lamellae of growth being cut obliquely.
In pl. X fig. 17 a cloven, aliform slit band is figured. The moieties of two lamellw are
seen in their length from the broad, scooped out basis to the pointed apex. In pl.
X figs. 27, 31, 37, details are given of the slit band of Pl. alata showing it, in fig. 27

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 93

(nat. size and magnified) sectioned transversally and the lamelle of growth as in the
former species, riblike with smooth interstices, directed obliquely outward, towards the
aperture of the shell. In fig. 30 the slit band is sectioned along its whole breadth in
a line from the whorl outwards, intersecting some ten lamellae of growth obliquely.
Section fig. 31 is taken parallel to the exterior border, showing the apices of eleven of
the elongated crescentshaped lines of growth. The same large development also obtains
in some other species which form the division »Alatwx» and of which several instances
are given on plate XI. This extraordinary increase of the slit band might at the first
look be regarded as a derived feature that attained such dimensions in the Upper
Silurian times. But on finding shells as low down in the series as in the Lower
Gray Orthoceratite limestone with a quite identical slit band one might as well ask
whether there not has been a regress from the development of this band to what we
find prevailing in a reduced shape during later geological pefiods. As we are not in
possession of materials ample enough from still older strata, we are not able fairly to
build any conclusion on this point. The aliform slit band is easily distinguished from
other lamellar expansions, such as are found in some Trochi and others, by a section,
through which the interior compartments become visible, whereas in the latter shells
the interior is compact.

The character of the slit band varies in the selfsame specimen of some species,
as for instance in PI. elliptica and it changes its nature and shape during continued
growth quite as is the case with the Bellerophons.

Another peculiarity amongst some of the Pleurotomariz is that the apex has been
either filled up with a solid mass of calcareous matter or has been subdivided in se-
veral small compartments through imperforated diaphragms or tabule. This peculiarity
they share with Murchisonia, Loxonema and Euomphalus, amongst which it is common.
At the same time this tendency is often accompanied by the formation of a scalarid
shell.

Species of Pleurotomaria are already found in the Lower Red Orthoceratite lime-
stone of Sweden, beginning with Pleurotomaria qualteriata. Pleurotomaria elliptic:
Histncer also is found in the Upper Gray Orthoceratite Limestone of Sweden. But it
was in the Upper Silurian seas, in the strata, which now make up the chief mass of
Gotland that this genus attained a considerable development in no less than 39 species
and varieties of changing aspect and ornamentation. These species may most con-
veniently be subdivided in groups, according to their agreement as to the chief cha-
racteristic, the slit band, along with which feature several peculiarities follow in the
general form of the shell, its ornamentation, the position of the band on the whorls
etc. I propose then to range the Gotlandic species in the following groups taking the
form and ornamentation of the slit band as the principal ground of division.

I. MULTICARINATZs. Slit band accompanied on each side by one or two lines,
crescents crossed by several longitudinal lines.
1. Pl. scutulata n.
2. Pl. gradata n.

o4 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

asiPl;

4. Bb

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Il. CRISPA.

Linnarssoni un.
voluta n.
claustrata n.
glandiformis 1.
biformis.
latezonata.
Hindei n.
Holmi n.

Wisbyensis.

Slit band with distantiated, sharpedged, regular crescents and smooth

interstices. Shell ornamented by many keels.

12s, Pl
LBsiFels
14. Pl.

Lloydii Sow.
dolium n.
laqueata n.

15. Pl. tubulosa n.
Il. FASTIGIATA. Slit band forming a blunt, elevated ridge, crescents flat, oblique,
densely packed; shell finely striated transversally.

LG. sue.
Icom
13.) Pl

LO pide.
20.- Pl.

robusta n.
lavissima n.
elliptica His.
bicincta Haut.
qualteriata SCHLOTH.

IV. SIMPLICES. Slit band narrow, plain, with small, regular crescents, shell sur-
face simply, transversally striated.

Mile LEA,
yp tanta ts
Yap abe fal
7H aed eB
V. INCISZ.
middle.
2h Py
202) Pt

VI. ALATA.

valida n.

Othemensis n.

comata n.

equilatera WAHLENBERG.

Slit band with large, lamellar crescents which are divided in their
Shell richly ornamented.

labrosa HALt.

limata nom. nov.

Slit band forming a large, thinedged keel all around the shell, both the

bordering lines of the slit band being widened and having developed into thin
lamella, which have coalesced with their edges enclosing the crescents of growth.

2750 Ph
28; /(Pl.
20r UPI

30P PI:

replicata n.

alata WAHLENBERG.
alata, var. subcarinata n.
alata, var. opposita n.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 95

31. Pl. pretexta n.
32. Pl. togata n.
33. Pl. frenata n.
34. Pl. undulans n.
35. Pl. Marklini n.
36. PI. cirrhosa n.

VII. PLANORBIFORMES. Shell discoid, slit band situated on the apical side near
the suture, narrow, much variable to its sculpture. Schizostoma Bronn p. p.
37. Pl. planorbis His.
38. Pl. helicina n.

VIII. NATICOIDEZ. Shell globose, slit band larger than in any other division, at a
level with the other surface, ornamentation of the shell of microscopic, oblique
lines, also crossing the slit band. Only one species known.

39. Pl. exquisita n.

Divisio I. MULTICARINATZ.

1. Pleurotomaria scutulata n.
Pl. VII, figs. 23—25, 28, 29

Shell conical, turbinated, whorls eight and a half, globose or rounded, separated
from each other through a deep suture, spire acuminate. Slit band situated exactly on
the middle line of the free body whorl and close to the suture on the superior, visible
part of the other whorls. It is narrow, somewhat concave and with dense, regularly
curved crescents and one or two faint longitudinal lines crossing them. The enclosing
lines are sharpedged. The slit band is on both sides environed by a belt of different
ornamentation than the other surface and this belt is enclosed by one prominent line
on each side. Within this area there are fine longitudinal and transverse lines cros-
sing and above the uppermost line there is also a broad space equally ornamented. This
median belt with its central slit band projects as a ridge all around the shell (fig. 25).
On each side of the belt there is a longitudinal slight concavity. The ornamentation
of the other surface consists of fine cross lines of equal size, forming nodules where
they meet and enclosing small squares and rhombs. The aperture is large and nearly
ovate. The columellar lip is reflexed and bent a little round the umbilicus, which is
large and funnelshaped.

Height 20 millim., breadth 17 millim. Aperture 11 millim. in height, breadth 9
millim. Apical angle 80°.

This elegant shell occurs in the limestone of Samsugn in Othem, at Stor Wede
in Follingbo and at Kyrkberget in Wisby. There is some variability in its shape, with
more slender spire (angle 55°) from Follingbo or quite the reverse, 85°, depressed, as
those from Samsuegn.

96 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

2. Pleurotomaria gradata n.
Pl. VII figs. 26—27.

Shell conical, trochiform, spire blunt, broad, whorls eight with regularly straight,
sloping sides of faint convexity, abruptedly bent along the superior suture through
the vertical and almost even zone around the slit band. This band is central on the body
whorl and remarkable as being one of the narrowest amongst all the Silurian Pleuro-
tomariw and perhaps amongst all known. It is reduced to a narrow fissure, a mere frac-
tion of a millimetre and thin as a knife edge. It continues open a long way round
the body whorl and the next, and then at last is filled up. But owing to its narrow-
ness it is impossible to discern any crescents on it. Like the related, preceding one,
the slit band is enclosed within a separate zone, differently ornamented from the other
surface and bordered by a narrow line on each side. In this median field there are
only transverse lines crossed by a few, obscure, longitudinal ones. On some distance
a blunt ridge is running on each side. The ornamentation of the whorls consists of
somewhat distantiated, transverse lines, connected by more narrow spiral ones and
parallel to the slit band; in the interstices microscopically minute transverse lines are seen.
The belt around the slit band does not form any prominent ridge as in the former
species, but rather a somewhat concave or straight facet on the whorl. The suture is
shallow. The aperture is rather more broad than high, its columellar lip is strongly
reflexed around the open umbilicus.

Height 22 millim., breadth 20 millim. Apical angle 69°. Another specimen has
24 millim. in height and 23 mill. in breadth. Found in numerous specimens in the
limestone of Sandarfve kulle and also in the gray limestone of Linde kulle.

Ornutert has described a Pl. Virensis from the Lower Devonian of France, and
this comes near to our species through its ornamentation and the slit band, though
its spire is lower.

3. Pleurotomaria Linnarssoni n.
Pl. XX fie. 21-—24)

Shell small, discoid, spire moderately prominent, whorls six, increasing in size
slowly and proportionately. They are adorned with a delicate network, on the apical
side consisting of intercrossing strie of which the transverse ones are directed back-
wards in an acute angle against the slit band. At the intererossing of these lines
small nodules are formed giving the surface a prickly appearance, with small pits in
the interstices. The slit band is placed below a narrow keel which divides the shell
exactly in two halves. It is exceedingly narrow and accompanied on both sides by
longitudinal lines, which are more prominent than the others. On the umbilical side
the whorls are more ventricose than on the opposite and also similarly ornamented,
The aperture is circular and the umbilicus is large and open. H. 4 mill, br. 8 mill.

KONGL SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 97

A dozen specimens have been found in the red limestone of Sandarfve kulle
and a few also in Linde klint. Through its ornamentation and its slit band it is nearest
allied to Pl. gradata from the same localities.

4. Pleurotomaria voluta n.
Pl. XIX fig. 25—29.

Shell discoid, tumid, with slightly prominent spire. Whorls eight, of regular
increase. The shell is on both the apical and umbilical side decorated with sharp,
sigmoid transverse lines curved towards the aperture near the suture and backwards
near the slit band. ‘They are crossed by finer, longitudinal lines, forming minute tu-
bercles where they meet. The section of the whorls is nearly ovate, high, arched
above, flattened below. The belt of the slit band is situated much beneath the middle
line of the body whorl and divides the flattened surface of the shell from the more
tumid. It is relatively large and is crossed by some longitudinal lines. The slit band
itself cannot be discerned through the bad preservation of exactly this part.

Through its general form and as far as can be judged in the conformation of
the zone of the slit band this species comes near to the preceding, from which it,
however, is sufficiently, distinct by its greater tumidity, its ornamentation and wider
umbilicus. Height 4 mill., br. 11 mill., diameter of umbilicus 6 mull.

Two specimens have been found in the red and gray limestone beds of Sand-
arfve kulle.

5. Pleurotomaria claustrata n.
Pl. VII f. 31—36.

Shell conical, trochoid, whorls seven or eight, gently convex, forming an acute
angle at the oblique slit band, which is placed somewhat above the median line of the
whorls. Its surface is almost flat, sloping inward, towards the columellar axis of the
shell, larger than in any other species of its group, bordered by two outstanding la-
mellar edges, as seen in sections, fig. 32 and 36. The crescents are large, distantiated -
and intersected by at least ten longitudinal lines. On the surface of the shell there
are fine, transverse, backwards directed stria, with interstices nearly five times as large
as them, and partitioned off by small striw, distantiated, parallel with the slit band,
causing a likeness with a ladder, as they are enclosed within their interstices and not
connected with each other in continuous longitudinal lines. If seen with a lens they,
at least in some parts of the shell, continue uninterrupted over the transverse lines,
fig. 35. The aperture is transverse, the columellar lip reflexed around the narrow,
but open and funnel shaped umbilicus.

Height 15 millim., br. 18 millim. Apical angle 85°. Specimens have been found
at Likkershamn, Samsugn, Follingbo, Kyrkberget. in Wisby and Snackgirdet near that town.

K. Vet. Akad. Handi. Band 19. Neo G lis

98 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

6. Pleurotomaria glandiformis pn.
Pl. VII fig. 37—38.

Shell elongatedly conical, turbinated, with seven convex whorls. The slit band
is placed a little above the middle line of the body whorl, relatively more narrow than
in the preceding species or nearly half that size. In the other whorls it is situated a
little below the superior suture. The bordering lines are not so prominent as in the
preceding. The crescents are nearly alike, distantiated, regular, crossed by two or three
longitudinal lines. The surface on both sides of the band has a regular, cancellated or-
namentation by equal sized lines, which at their crossing point form a little, elevated
nodule. Suture deep. Aperture elongate, higher than broad, umbilicus narrow, but
open.

Height 19 mill., breadth 15 mill. Aperture in height 8 mill., br. 7 millim. Api-
cal angle 56°.

It has been found in many specimens in the red limestone of Sandarfve kulle,
a few in the gray limestone and also in the neighbouring Linde klint.

This species is very nearly related to the preceding one, having the slit band
formed on almost the same type, but it differs through the ornamentation of the sur-
face where small nodules are formed at the crossing point, as well as in the shape of
the shell and the whorls, which are angular in the former and evenly rounded in this
species.

7. Pleurotomaria biformis n.
Pl. VII fig. 39—492.

Shell broadly conical, turbinated, with seven tumid whorls, four times as broad as
high and having the slit band a little below the middle line of the body whorl and
midway between the upper suture and the median, transverse line of the other whorls. It is
much concave, forming a shallow groove around the shell, with sharp, elevated borders
on both sides. The crescents are fine, narrow, densely packed, more curved than in
the others and crossed by numerous, equally fine, longitudinal streaks. As seen by the
fig. 42 the ornamentation is widely dissimilar above and beneath the slit band, being
imbricate and crossbarred above, and with two different sets of striae below: one con-
sisting of coarse, irregular and distantiated transverse wrinkles, in their direction corres-
ponding with those above the band, though meeting the slit band in a more acute
angle, the other crossing these obliquely, nearly parallel with the slit band. They are
microscopically minute and remind of those which cover the whole shell of Pleurot.
exquisita. There is besides on the whorls an obtuse ridge beneath the slit band, parallel
with it and close above the suture the whorl ends in a somewhat nodular ridge or
string. The aperture is nearly circular, The umbilicus is narrow and open, on its distal
side enclosed by a low ridge, which emanates from the back of the columellar lip, on
its proximal side it is hemmed in by the basis of this lip, which is enlargened as a
broad lamella and nearly hides the umbilicus, when seen from above.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 99

Height 23 millim., br. 20 millim. The aperture has in height 13 willim., in
breadth 10 mill. Apical angle 69°. A specimen from Wisby is 29 millim. high and
at largest 25 mill. Apical angle 71°.

This species has been found in six specimens in the shale at Djupvik in Eksta
and in fifteen specimens in the same shale bed near Wisby; from the later locality
nuclei mostly have been collected. A single specimen from the middle limestone stra-
tum near Wisby belongs probably also to this species, as well as two badly preserved
specimens from Kalens Qvarn, north of Wisby.

8. Pleurotomaria latezonata pn. ')
PL 28 inks ie

Shell conical, turbinated, with five tumid whorls and fragments of the sixth or the
body whorl. Slit band situated on the middle of the free whorl or near the superior
suture in the lower ones. In its ornamentation it resembles much that of the prece-
ding species, but it is not so much concave or scooped out, the crescents are not so
much curved, rather thicker or coarser. The ornamentation below this band consists
in crossbarred stria, with a few larger, longitudinal ribs. The suture is deep. The
shape of the aperture and the umbilicus cannot be ascertained as the shell is broken

in those parts. :
Height 7 millim., breadth 6 millim. Apical angle 77°. Only one specimen has

been found in the middle limestone of Wisby (b).

It comes near to the preceding species through its slit band, but the shape and
ornamentation of the whorls differ, being in this species thrice as broad as high and
in the former nearly four times as broad as high.

9. Pleurotomaria Hindei n.
Pl. XIX f. 15—16.

Shell turbinated with seven tumid, transverse whorls, of which the body whorl is
more than double the size of the others and nearly double as broad as high. The slit
band, which is situated a little below the median line of the body whorl and near the
upper suture in the other whorls, is broad, with thick, projecting margins and covered
with regularly curved crescents of growth. There are some faint traces of longitudinal
lines crossing them. The surface below the slit band is evenly rounded, nearly flatte-
ned out. There are minute, longitudinal, as well as transverse strix of equal size
forming regular squares and at their meeting point there seems to have been a sinall
gibbosity, causing a prickly surface. ‘The umbilical surface is corroded, but, as discer-
nible on some patches, has had the same sculpture. The aperture is nearly circular,
the outer lip thin, the inner one reflexed as to form a little tube along the narrow
umbilicus and broadly enlarged at its basis. H. 15 mill., br. 13 mill.

') IT was not aware that a Pleurot. latifasciata Mac Coy already existed, when I had named this species
Pl, latefasciata on page 18.

100 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND P'TEROPODA OF GOTLAND.

A single specimen found in the limestone at Samsugn in Othem. The form of
the slit band and the sculpture of the surface unite it with the »Multicarinata» and
especially with Pl. scutulata from which it is distinguished through the different slit

band.

10. Pleurotomaria Holmi n.
Pl. XIX fig. 18—20.

Shell conical, turbinated with seven ventricose whorls, body whorl of the same
size as the others taken together, all nearly thrice as broad as high. The slit band
is situated a little below the median line of the body whorl and exactly on the me-
dian line of the other whorls. It is large, projecting, with convex surface. As far as
ean be made out on the much corroded band, the crescents are regular and distan-
tiated. The ornamentation on both sides consists in thin, exert, transverse and longi-
tudinal lines, closely set, forming a dense network with indistinct nodules at the cros-
sing point. The transverse lines have a sigmoid direction and are regularly curved
backwards close to the slit band. Below the slit band there is a sharpedged ridge
near the suture and above that band a slight bulging out of the surface as a callosity
is seen in some specimens. The aperture is circular, and the umbilicus is narrow. H. 15
me or 2 manlil

A few specimens have been found in the middle limestone near Wisby. From
the limestone at Slite a small shell (Pl. XIX f. 17) has been obtained nearly resemb-
ling the former as to its shape and the prominent slit band. This is, however, placed
exactly on the median line of the body whorl and the ornamentation seems to consist
only of transverse striw. H. 5 mill., br. 5 mill.

11. Pleurotomaria Wisbyensis nv.
Pl. XVIII fig. 50—51.

Shell rather depressedly conical, turbinated, with six ventricose whorls separated
by a shallow suture, the apex obtuse and spire short of five whorls, together smaller
than the body whorl. The slit band is placed somewhat above the middle line of the
body whorl and is hidden from view in the smaller whorls. It is prominent and con-
vex as to its surface. The ornamentation below the slit band is of the common reti-
culate crossbar pattern, the longitudinal lines being stronger than the transverse ones.
The same sort of sculpture seems to have oceupied the umbilical surface, but is mostly
effaced. The aperture is circular with thin lips. The umbilicus is deep and wide, and
defined through a sharp, abrupt edge. H. 10 mill. br. 10 mm. Largest specimen from
Samsugn has h. 15 mm., br. 13 mm.

Four specimens have been found in the superior limestone on Kyrkberget in
Wisby and one in the quarries of Samsugn in Othem. It is only in consequence of
it is reticulate sculpture this shell has been placed with the Multicarinate, and its posi-
tion must be afffirmed through the find of more complete specimens.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 10]

Divisio II. CRISPAs.

12. Pleurotomaria Lloydii Sowerrsy.
Pl. VII fig. 43—49, pl. VIII fig. 1.

Pleurotomaria Lloydii 1839 Sow. in Sil. Syst. H, 619, pl. 8 f. 14.
1843 Morris Catal. Brit. Foss. 1 Ed., 158.
Murchisonia Lloydii 1841 Arcutac & Verneuit Bull. Soc. Geol., 160.
1848 Bronn Nomenelator, 748.
1850 D’Orsieny Prodrome J, 31.
1854 Morris Catal., 259.
1855 Mac Coy Palozoic Fossils, 293.
1867 Sauter Siluria, 532.

Shell turbinated, whorls six or seven, ventricose. The slit band is situated exactly
on the middle line of the body whorl and a little below the upper suture of the other
whorls. It is broad, elevated, with an even surface and, as far as can be made out
from the not quite complete specimens, covered with distantiated crescents and smooth
interspaces. Above the slit band there are some twelve longitudinal ridges of equal
size and parallel to them smaller, threadfine lines, both crossed by fine, distantiated
transverse lines. Beneath the slit band the longitudinal ridges are not so numerous,
four at the highest and much unequal. Near the suture the transverse lines are thicker
than higher up. The apex of the shell has been filled up with solid, calcareous matter
and the lowest whorl of the nucleus ends consequently in a blunt point. The aper-
ture is large and obliquely ovate (Pl. VI f. 43). The umbilicus is narrow and open.

Widely spread as this shell is, it seems to be much variable and there are many
Gotland specimens, which only hesitatingly and provisionally can be refered to PI.
Lloydii, as the English species according to the figure given by Sowersy is more elon-
gated and the whorls by far not so ventricose as in the former. Mac Coy 1. ¢. also
says that he has not seen specimens of the same length as in Sowsrsy’s figure. His
descriptions nearly agree with the Swedish specimens.

The variety from the shale beds near Wisby (PI. VII figs 46—49) has still more
ventricose whorls and the parts around the slit band not so much angularly prominent
as in those from the other localities and it may rank as a well distinct variety.

Next, there is a depressed, short form, chiefly found as nuclei with indistinct
impressions of sculpture and with the body whorl nearly elliptical in a longitudinal
section. A few specimens of this, concerning which it for the present cannot be de-
cided, whether it is a variety or an independent species, has been found at Wester-
garn, in Ostergarn at Gannviken and Grogarn, and in Ardre. Its dimensions are: height
32 millim., breadth 31 mm. apical angle 87 °.

The typical specimens of Pl. Lloydii attain a height of 49 millim., breadth of
34 mill., apical angle 56 °.

It has chiefly been found in the shale beds at Wisby, Follingbo, Westergarn,
Djupvik in Eksta, Habblingbo, Alfva saw mill, Qvinnegarda in Hafdhem, the canal from

102. G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Wisne myr in Fardhem, Ostergarn, Stor Myr in Rute, but also in the limestone beds
of Faré, Medebys in Hall, Wisby Kyrkberg, Djupvik in Kraklingbo. It very seldom is
found but in nuclei. In some instances the interior nacreous coating is retained as in
specimens from Ostergarn.

Pl. percarinata Hatt Pal. N. Y. Vol. I p. 177 pl. 38 fig. 4 resembles somewhat
this species.

13. Pleurotomaria dolium un.
Pl. IX fig. 1—3.

Shell turbinated, rotundate, with the body whorl much in excess of the other
three whorls. Slit band situated a little below the middle line of the body whorl,
large, scooped out as to form a regular groove around the shell with somewhat out-
standing borders. The crescents are regular, wide apart, with prominent lamellar edge
and smooth interstices. The ornamentation above the band consists in two or three
obtuse longitudinal ridges, a little nodular where they are crossed by the fine trans-
verse lines, which are obliquely lamellar near the slit band. Beneath this band there
is only a single sharpedged ridge, halfway between the band and the suture, and
oblique, closely set, narrow, transverse lines. Suture very shallow. The aperture is
nearly circular, no umbilicus can be discerned.

Height 6 millim., breadth 5 wmillim., body whorl nearly 4 millim. in length.
Apical angle 77 °.

Only one specimen has been found in the sandstone of Bursvik. It comes near
to the smaller specimens of PI. Lloydii (Pl. VII fig. 43, 44) but is easily distinguished
through its broad slit band, its want of umbilicus and the form of the whorls.

14. Pleurotomaria laqueata n.
Pl. IX fig. 4—6.

Shell turbinated, whorls five, ventricose. The slit band more than a millimeter
in breadth, convex, is situated a little beneath the median line of the whorls, orna-
mented with laminated or, as it were, imbricated crescents. It is bordered by two
sharp edged lines, one on each side, and with jagged outside. On each side of this
band there is a varying number of parallel, clevated, longitudinal ridges. In one
specimen there is only one beneath the band and one above. In another specimen
there are three ridges above the slit band and one below. All these ridges are cros-
sed by transverse, lamellar striae with thin, elevated edges and directed obliquely
against the slit band, which they do not cross. Suture shallow. The aperture is oval
with the columellar lip thick, reflexed, without any umbilicus.

There is some variation as to the distance and number of the transverse striz,
which lie imbricated with lamellar edges and through their varying position giving
the surface a more or less fine striation.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 103

Height 25 millim., width of body whorl 17 millim. Height of aperture 12 millim.
Width of body whorl in a fragmentary specimen 23 millim.

A few specimens have been found in the uppermost limestone of Klinteberg,
Fréjel and Wisby (b. c.).

15. Pleurotomaria tubulosa n.
Pl. IX fig. 7—10.

Shell turbinated, with ventricose whorls, of which only the body whorl and part
of the next are left, in the only specimen, which has been found. The slit band is
placed somewhat beneath the median line of the body whorl, relatively narrow, pro-
minent and much convex, the crescents much more distantiated than in any one of
the other Silurian Pleurotomariw and continue backwards as a narrow tube, which is
overlapped by the next crescent, the whole thus forming a tube in tube system. The
band is bordered by low lines and these and the direction of the striw against. it
distinguish it from the nearly alike keels above and below. There are three narrow
and prominent keels above the slit band and one beneath the same. When crossing
them the transverse, ornamental lines are lifted upwards and obliquely backwards,
more strongly in some of them, than in others. These stronger transverse lines of
growth are in a peculiar manner accompanied by smaller ones in the interspaces be-
tween the keels, diverging in an acute angle from their side or in gentle curves
forming with them an ovale, as is shown in the details of figures 9 and 10. These
lamellate, transverse lines continue also across the suture, which is shallow, and they
are thus connected with the lamelle of the adjoining whorl. The surface between
these large ridges is finely, transversally striated. On the umbilical surface the coarser
strie interlace and form a sort of network, with large meshes. There is no open um-
bilicus, and the aperture seems to have been obovate. Height 26 millim. breadth 25 mill.

Only one specimen from Hammarudd in Kraklingbo.

Divisio Ill. FASTIGIAT ZA.

16. Pleurotomaria robusta n.
Pl. VIII, fig. 2—7.

Shell globular, consisting of six highly ventricose whorls, gradually ascending in
an angle approaching more or less to a right angle, 82—90°. Surface nearly smooth
or with very fine, transverse striw grouped in larger bands. Slit band nearly on the
middle line of the body whorl and near the upper suture in the other whorls. It is
enclosed within two fine, neatly defined lines. A little below its median line it has
an obtuse ridge, thus nearer to the inferior border, and the band consequently standing
out from the surface in an angle, the sides of which are a little concave. The cre-

104 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

scents are thickly set, oblique, with their largest bend coinciding with the median ridge.
Above the slit band some faint longitudinal stria are seen, intersected by distantiated,
transverse ones. Beneath the band there runs an angular keel. The surface is for
the rest almost glossy and shining. The suture is deep. The aperture is large, trans-
verse, the columellar lip is thick, strongly reflexed and nearly hiding the opening of
the umbilicus, which continues in an oblique direction inwards.

The specimens are generally much worn or obscured by corrosion and by for-
eign bodies, which have grown on the surface and it is consequently difficult to get
a clear idea of its appearance. On the nucleus the impression of the slit band forms
an angular, projecting keel. Height 55 millim., breadth at the base 55 millim., aper-
ture 80 iill.

Several specimens have been obtained from the shale beds of Djupvik in [ksta,
and Petesvik in Habblingbo.

17. Pleurotomaria robusta var. levissima n.
Pl. VIII fig. 8—9.

Shell globular, with six whorls, slit band placed exactly on the middle of the
whorl, ornamented with the most delicate crescents and moreover with a narrow
ridge more median than in the former. The band is for the rest, not so much
angularly elevated, rather square cut, as seen in the section. The surface on both
sides of the band is smooth and glossy, with only few obscure spiral bands and with
scarcely perceptible, transverse sinuous striw. The suture is shallow. The aperture
is circular, the interior lip thin, reflexed around the umbilicus which is narrow and
open. Height 17 millim., breadth 19 millim., height of aperture 11 millim.

Found in the shale of Djupvik in Eksta.

18. Pleurotomaria elliptica His.

Pl. VIIL fig. 10—14.
Trochus ellipticus 1829. Hursincer Tabl. ed. 1, 11.
1831. Ip. Anteckn. V, 11, tab. 2 fig. 2, 2, 2,
1831. Ip. Tabla ieds 25) 05
1837. Ip. Leth. 35, tab: 11 fig. 1 a—b.
1841. Ip. Foérteckning 6fver en geognostisk och petrifikatsamling fran Sverige

och Norrige, 61.
1843. Porrtock Geol. Rep. Londonderry, 414, pl. 31 f. 1, very doubtful.
1848. Bronn Nomenelator, 1300.

Turbo antiquissimus 1840. Ercnwatp Sil. Schichtensyst. Estlands, 119.
1842. Ip. Urwelt Russlands, 2, 53, tab. 2 f. 7.

Turbo ellipticus 1846. Ip. Bullet. Moscou, XIX, 104.

Pleurotomaria elliptica 1858. Frrepr. Seamipy Silurform., Esthlands, 203.

1867. TORNeust Lagerféljden i Dalarnes Undersiluriska bildningar, 19.
1876. Ferp. Rormer Leth. geogn. 4 Ed. Atlas, 1 Thi. pl. 5, f. 3.
1880. Anoruin & Linpsrrém Fragmenta siluriea, 13, tab. XV, fig. 8.
Pleurotomaria antiquissima 1860. Brenwaup Leth. Rossica I, 11, 1168, pl. 42 f. 17 ab.
Pleurotomaria subconica 1865. Kuserutr (nee Haun) Veiviser 7, fig. 15.
Flemingia elliptica 1882. Dr Konryek Faune II, pt. 5, 94.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. (9. N:0 6. 105

Shell largely conical, trochiform, with ten gently convex whorls, angular at the
shallow suture where the slit band is placed in the older whorls, being median in the
free body whorl. It is comparatively large, with a longitudinal ridge above the middle
line, not far from the superior border. This, however, as may be gathered from the
figures 10, 12, 14, varies, the ridge being nearest the central line in specimen fig. 14,
which is from the Lower Silurian of Oland at Lerkaka, and more prominent than in
any one of the others. In specimen figure 10, the ridge of the slit band is placed
nearer to the superior border than in the others and is only very little prominent.
The crescents are consequently more or less oblique, as their greatest curve coincides
with this ridge. They are densely set, fine, thicker at the ridge and thinning out
towards the borders. The surface on both sides of the ridge is a little scooped out,
as seen in the profiles delineated. This median ridge does not, however, continue all
the way round, but ceases in the vicinity of the aperture, as seen in fig. 10, upper
detail, where the large slit band is only obscurely hemmed in by bordering lines and
covered with regularly curved crescents. The slit is angular, tongue shaped with evenly
curved sides. On the nucleus the slit band has made an impression as a shallow
groove. The thin shell which seldom is preserved entire, is covered by fine stria,
which meet the slit band as usual in a highly acute angle. At their basis, near the
suture they are more apart and form band like plaits. The aperture is transverse,
with the exterior lip thin and sharp and the interior lip regularly reflexed, but not
so much as to hide the narrow and open umbilicus. Length 30 millim., breadth at
the basis 26 mill., apical angle 71 °.

Only two specimens have been found in Gotland; one, fig. 10, in a detached
block from the Norderstrand near Wisby, the other, fig. 12, from Ostergarn. As to the
derivation of the former, it is questionable whether it really has been included in a
Gotland rock and rather not has been found in an erratic block, of which some, spread
over Gotland, contain Lower Silurian fossils. The specimen from Ostergarn seems
indeed, to judge from the rock, to have been found in the Upper Silurian strata of
that locality.

There cannot be any doubt that this species is the same as that so named by
Hisincer. The original specimens of this author are contained in his own collection,
now in the Paleontological Department of the Swedish State Museum and consist of
two badly preserved nuclei from Dalecarlia, without any traces left of the shell. One of
them, a little compressed from the sides, is the original specimen to his figures in
»Anteckningary pt. 5, two af which have been copied in the »Lethwa Suecica. Later,
several complete specimens have been found in strata of Oland, contemporaneous
with the former. As can be seen on the plate VIII to this work, fig. 14, the Oland
specimen has only trifling deviations in the character of the slit band, such as only
ean be expected in a species of so wide a geological range. There exists then, as I
suppose, no necessity to subdivide this species into new ones, as some later authors
seem inclined to do by always citing »Plenr. elliptica His. sp» There may at the
utmost be mutations. The oldest known mutation is from the Upper Gray Orthocera-

K. Sy. Vet.-Akad. Handl. Bd. 19. No 6. 14

106 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

tite limestone of Dalecarlia and Oland. It has almost the same general form as the
Gotlandic one, the ornamentation is quite the same, the slit band is different by the
longitudinal ridge, though still above the median line of the band, being placed nearer
to it than in any other of the later mutations, where it is placed higher. In the speci-
men from Wisby (fig. 10) the ridge is placed at the highest and in the next from
Ostergarn it is midway between the position in the two former. There are, of course,
in this, as in almost all other species of shells individual variations as to the greater
or smaller convexity of the whorls, the size of the apical angle, of very little im-
portance as to the specific distinction. Thus I think that Pl. subeconica Ksrrutr may
without hesitation be placed in this species. It is not at all identical with Pl. sub-
conica Har, as this author expressly states, that it is »cancellated», whereas the
Norwegian shell only is transversally striated. Murchisonia Hercyniz Bruiines, Paloz.
Foss. Canada p. 158 f. 141, comes also near to Pl. elliptica, but is more elongated,
with more acute apical angle, and may possibly be only a variety of this. PI. elliptica
Gotpruss Petrif. Germ. p. 50, pl. 178 fig. 4, is not at all related to our species. It is
a sinistral and longitudinally carinated, Devonian species, only found as nucleus. Dr
Koninck led by the general, exterior shape thinks, in his Faune Carbonif. de Belgique
II pt. 3, p. 94 that »Trochus ellipticus Hisivcer» ought »probablement» to be placed
in his genus Flemingia, but this cannot be so, since the slit band has been demon-
strated in this species.

In some specimens, as that from Wisby and that figured by Frrp. Rormer from
the Lower Silurian, there is the peculiarity, that the impression of the slit band on
the nucleus is a shallow groove, while it in all other specimens is a distinct keel or
at least not so much grooved. The geological range of this species in Sweden is then,
according to the statements, given above, from the Upper Gray Orthoceratite limestone
included, through the Chasmops limestone into the Upper Silurian shale beds of
Gotland.

19. Pleurotomaria bicincta Hat.
Pl. VIII fig. 15—25.

? Pleurotomaria angulata 1838 Sow. in Sil. Syst., 641 pl. 21 f. 20 (not identical with Pl. angulata Mac Coy
Sil. Foss. Ireland, 16, pl. I f. 17).

Murchisonia bicincta ') 1847 Haut Pal. N. York vol. I, 177 pl. 38 fig. 5 a—h.

1850 Saurer Geol. Survey of Canada, Organic Rem., Dee. I, 19, pl. IV f. 5—6.

Turbo sp. »probably new» 1851 Sauter Qu. Journ. Geol. Soc. vol. VIII, 178, pl. IX feo Lee

Pleurotomaria sp. 1858 Fr. Scumipr Estland, 202.

2? Pleurotomaria latifasciata 1862 Mac Coy Synops. Silur. Foss. of Ireland, 15, tab. I f. 16.

Trochonema (Bunema) fatua 1868 Hatt 20:th Rep. N. York State Cab., 345, pl. 15 f. 7—8. Revised. Ed. 394, tab.
15, fig. 7—8.

Trochonema rectilatera 1872 Hatt & Warrrrenp 24:th Rep. N. York State Cab., 193, figured in the 27:th
Rept. pl. 13 f. 4—5.

Shell conical, turbinated with five or six whorls. Each whorl is moderately con-
vex and shows, when free, three different faces, the inferior one, sloping against the

1) Murchisonia bicincta? Merk & WortHen Geol. Illinois vol. III, 317 pl. 3 f. 4 is too obscure to be
with any certainty regarded as this species.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wn:o 6. 107

central axis, is near the suture swelling in a narrow obtuse ridge, the median face
is parallel to the axis of the shell, and the superior one is moderately convex sloping
outwards. The median face is confined within the characteristic two longitudinal rid-
ges, which are more or less prominent in the different specimens. Of these ridges
the largest or second one from above is the slit band, as may be learned through a
closer inspection and by the direction of the ornamental strix of the surface on each
side of it. As seen in the figures, especially in fig. 23, it is distinctly separated from
the other surface by bordering lines. It is formed on the same plan as in the pre-
ceding species, of oblique, dense crescents, the obliquity of which is influenced by the
position of the longitudinal ridge. This ridge varies as to its position more than in
any other species of this division, being placed in the middle of the band (fig. 19, 21)
or near the superior border (fig. 22) or quite on the contrary near the inferior border
(fig. 23). Its variations as to the size may also be perceived from inspection of such
extremes as figs. 19 and 22.

The surface is densely covered by transverse, fine, elevated strix, which are
directed backwards from the suture in an elegant curve. Above the slit band they
continue nearly vertically and again above the uppermost ridge curve backwards.
There is some variation as to their fineness and proximity, of which figures are given.
From Gothemshammar there is a peculiar variety (figs. 24—25) agreeing in all par-
ticulars with the described specimen, but being provided with a ridge beneath the slit
band, midway between this and the suture. The aperture is elongated, nearly twice
as long as broad, the exterior lip angular, thin and sharp, the inner lip reflexed in a
large, smooth fold, which is often scooped out longitudinally and entirely covers the
umbilicus.

The nucleus is strangely globose in the older whorls, only angular in the body
whorl, and a thin covering of a nacreous stratum is left behind on it.

Dimensions. Largest specimen 65 millim. in height, 35 mill. in breadth, apical

angle 62 °. Height. Breadth. Apical angle.
Specim. fig. 15 45 mm. 33 mm. i Sias
== ills 45 » 3) ob Site
— 24 LO» Gore G2y::

By this and many other instances may be found how little reliance can be put on the
size of the apical angle as a specific character. This beautiful and characteristic shell
has been found in several specimens in many localities of Gotland, in Faré at Lansa,
at Slite in the shale beds and the superimposed limestone, Gothemshammar, Ostergarn,
Ardre, Samsugn in Othem, Martebo, in the limestone of Wisby, at Stor Wede in Fol-
lingbo, Krokstiide in Tofta, Westergarn, Djupvik in Eksta and in a section between
Stjernarfve and Lefvede, on the shore of Kylley, in the canal near Atlingbo church.
This species has a geological range from the Lower Silurian strata of Borkholm
in Esthonia, through the Upper Silurian into the Upper Helderberg strata of the
Devonian group. Turbo bicingulata F. A. Roemer Palwontogr. vol. 3 pl. V fig. 20
from the Devonian of the Harz mountains is probably also identical. Its geographical
distribution is equally wide, as it besides Sweden occurs in N. America, Scotland,

108 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Ireland and Russia. It is consequently one of the most characteristic Gastropods of
the Silurian formation. That there should be a great amount of variation in a form
of such wide a horizontal and vertical distribution is nothing more than could be
expected, As the figures show, there are elongated and short forms. The variety
from Esthonia, fig. 17, is the shortest and more coarsely striated, the body whorl nearly
double the size as the others. Its height is 28 millim., its breadth 30 mm. The spe-
cimens from the limestone of Slite, figs. 18, 19, are also short and broad reminding
of the Devonian form which Hann and Wurrrre rp have called Trochonema rectilatera.

20. Pleurotomaria qualteriata ScuLoruem.
Pl. XIII fig. 15—16.

Helicites qualteriatus 1820. Scuioru. Petref. Kunde, 103.
1822. Ip. Nachtriige, 61, tab. XI f. 3a—c.
Solarium ? petropolitanum 1830. Panper Beitriige zur Geogn. Russlands, 150, tab. I f. 3 a—3b, tab.
28 f. 14.
Euomphalus qualteriatus 1834. Gonpruss in Kiopen, Versteiner. Mark Brandenburgs, 155.

1835. Bronn Leth. Geogn. t:e Aufl. Bd I, 94, Taf. IL f. La,b.
1840. ErcnuwaLp Schichtensyst. Estlands, 115.

1844. Go.pruss Petrefacta Germanizx II], 81, tab. 189 f. 3.
1845. Vernevuit Russia, vol. 2, 333, tab. 23 f. 1 a—b, 2 a—b.
1848. Savrer Memoirs Geol. Survey LI, 1, 356, pl. XIV f. 7.
1858. Frizpr. Scumipr Geol. Estlands, 206.

1865. Ksrrutr Veiviser, 7

1567. ToRNeuist Lagerfoljden i Dalarne, 19.

1869. Karsrrn Versteinerungen... in Schleswig und Holstein. 43, tab. 14
fig. 9 a—b.

1880. AnGeLIn & Linpsrrom p. p. Fragmenta Silurica, 12, tab. XV f. 10, 11
(excl. fig. 12—14).

Pleurotomaria lenticularis 1843. Conrad in Emmons Geol. N. York pt. Il, 392—393 f. 101,2 & 102.
Pl. lenticularis Hann Pal. N. Y. vol. I, 172 is quite different.
Euomphalus gualteriatus 1848. Bronn Nomenel., 480.

1854. Frrp. Roemer Leth. geognostica ed. 3, I, 1, 459, tab. 2, f. 1 a—b.
1860. Ercuwaup p. p. Letheea rossica I, u, 114.

Straparollus qualterianus 1850. D’Orsieny Prodr. I, 6.

Straparollus pseudoqualteriatus 1850. Ip. Ibid. I, 30.

Rhaphistoma qualteriatum 1859. Santer Canad. Organic Remains, Dec. I, 13.
2Ophileta Ottawensis 1860. Briturxes Canadian Naturalist, 166, fig. 9—10.

Shell discoid with short, flat spire of five and a half whorls. The apical side
is gently convex or nearly flat and the sutures are very shallow. The whorls are on
the umbilical side more convex, increasing in height and convexity near the umbilicus,
which is large and open.

The angle formed by the slit band is interposed between the umbilical and apical
sides and is highly acute, of 30°. Its limits are designated through the converging
threadfine ornamental lines of the surface which for the rest is smooth. The slit band
is at largest on the apical side and there separated frem the other surface through
no distinct bordering lines. The crescents are fine and indistinct.

As may be perceived from the dimensions given below, the Gotland mutation of
this species is more discoid than the older, which are relatively higher in their last whorl.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. n:o 6. 109

The Gotland specimens are only nuclei and consequently the details of the sur-
face have been taken from Lower Silurian specimens of nearly the same form.

In the oldest shale beds near Wisby six specimens or nuclei have been found in
situ and thus there is certainty that they have not been transported. As may be scen
through the dimensions given, they are more flat than those from the Lower Silurian
strata. Largest diameter 43 millim., height 15 millim. Breadth of the largest whorl 16
millim., height of the same 11 mill., while in one of the Lower Silurian ones the
largest whorl near the aperture is 18 millim. in breadth and in height 13 mill. A spe-
cimen from Borkholm in Esthonia has the aperture of 18 mill. in height and 20 mill.
in breadth. Specimens which nearest resemble this are first met with in the upper-
most strata of the Lower Red Orthoceratite limestone from Killa in Oland. It then
occurs in numerous specimens in the Lower and Upper Gray Orthoceratite limestone of
Dalecarlia and Oland and also of other provinces, and returns again in the uppermost
limestone strata of the Lower Silurian. Coéval with this species there lived at least
one nearly allied species and two others which have been rather confounded with them.
The characters of all four are shortly given below, in order in some way to clear up
the distinctive features of these very common fossils.

1. Pleurot. qualteriata Scunotu. 1820, with flat, horizontal or faintly convex apex,
slit band largest on the apical side, only discernible through the direction of the sculp-
tural lines.

As to the quaint name of this species it seems that Scunoruem, when he com-
pares it with Helix gualteriana, had intended to name it gualteriana or gualteriata,
but that through some error the g had been changed into a q. He, nevertheless, re-
tained the later, without giving any clue to its derivation.

2. Pleurot. obvallata Wanvenserc 1818 (Petref. Svec. p. 73 tab. IV fig. 1—2)
with prominent apex of steplike whorls, slit band (pl. XII fig. 18) large on the api-
cal side, narrow on the umbilical. side; in its centre with densely packed crescents,
nearly resembling those of Pleur. bicincta. This species is more common than the
former and it has, in the same way, filled up the apex with solid calcareous matter.
It is found in the Lower and Upper Gray Orthoceratite Limestone of Oland and Dale-
carlia. Then there are two other species which belong to a quite different type, as
they have the slit band built upon the same plan as prevails in the Division of the Alatz.

1. Pleurot. marginata Ercuwatp. This forms the transition to the next ex-
treme species. It is large, with six ventricose, contiguous whorls, on the apical
side sunken in a wide, open funnel, their inner face abruptedly sloping inwards. The
slit band on the inferior edge of the whorls is thin, lamellar, and winglike. The sur-
face is finely, transversally striated, on the umbilical side there are broad plaits. It
occurs in the Lower and Upper Gray Orthoceratite limestone of Oland. A variety,
with the youngest whorls uncoiled, belongs also to this species and occurs in the
youngest limestone beds of Oland. There are several diaphragms in the apex of this
shell. This species is related to the Canadian Ophileta as it has been described by
SALTER in »Canad. Organ. Remains». Dec. 1 p. 16, through the slit band is more de-
veloped in PI]. marginata.

PO: “G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

1. Plewrot. sp. (==? Eccyliomphalus alatus Roemer, ? Helicites centrifugus Wax-
LENBERG, see also PI. XV, fig. 12—14 in »Fragmenta Silurica). This is a smaller species
than the former, more uncoiled and tending to complete scalarid formation. The in-
side of the whorls is not so steep as in Pl. marginata and the funnel formed on the
apical side not so regular as in that. The sculpture is more distinct of coarse trans-
verse lines and the slit band is more prominently alate or laminar than in them. This
occurs in the Lower Gray Orthoceratite limestone, in the Upper Red and Upper Gray
Orthoceratite limestone and also in the Chasmops limestone of Oland.

It is of such forms as this, that the genus Eccyliomphalus has been built up,
commingled with others, as evolute Euomphali. To elucidate their distribution in
time the following table may serve.

| tare
Lower Red |Lower Gray| Upper Red |Upper Gray Ghasmons Youngest eee Shale
Orthoe. Orthoc. Orthoe. Oxrthoe. Tan aie _ | Limestone ie Ses of
Limestone. | Limestone. | Limestone. | Limestone. : | of Oland. Dal em Gotland.
| alecarlia.
| -
1 Pl. qualteriata Secu. __._...- * * * ? *
12 Pl. obvallata Wau. ......------- * *
3 Pl. marginata Eicuw. -........-.- * * *
(PAPAS NA) out canes ee eee : 4 + * 4

Divisio IV. SIMPLICES.

21. Pleurotomaria valida n.

Pl. IX fig. 11—13.

Shell elongate, turbinated, with seven or seven and a half whorls, which are ven-
tricose, the superior ones forming an obtuse angle midway between the median line
of the whorl and the suture where the slit band is situated.

The whorl is almost flat beneath the slit band sloping suddenly inwards towards
the suture. There are only some slight traces left of the sculpture of this uncom-
monly thick shell, and it consists in transverse striw. The slit band is very large,
nearly 4 mill. across, the height of the whorl being 27 mill. The aperture is oblong
and the columellar lip thick and reflexed, so as to hide the umbilicus of which there
is no trace, as the columella is solid. The shell seems to have been much exposed and
weathered before it was enclosed in the limestone. ,

It has been found in a hard, crystalline limestone near Lillugn in a wood between
the parishes of Ardre and Alskog. PI. inflata Mac Coy, Sil. Foss. of Ireland p. 15
pl. 1 f. 15, somewhat resembles this shell in form.

') Pl. replicata, nearly related to this, is found in the Gotland shale.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wN:o 6. 111

This is the largest of the Gotlandie Pleurotomariw, attaining a length of 1,03
decimeter and a width of 60 millim. ‘The thickness of the shell near the umbilicus is
5 millim. and in the body whorl of the largest specimen 6 m. m.

22. Pleurotomaria Othemensis pn.
Pl. IX fig. 14—16.

Shell elongate, turriculate, with seven ventricose whorls, which form an obtuse
angle along their median line, where the slit band is situated. This band is relatively
large, with convex surface, covered with regular, distantiated crescents. It is hemmed
in by two much projecting lamelle which grow out in converging direction. The or-
namentation is only transverse, of lamella, with a peculiar wavy or broadly indented
edge. The aperture is ovate, the outer lip thin, with the broad slit in the middle,
the inner lip a little more thickened, reflexed around the narrow umbilicus. H. 34
mill., br. 25 mill. Apical angle 63°. It has been found in several specimens in the
richly fossiliferous limestone of Samsugn in Othem. It might at first have been taken
for a variety of the former. But its more narrow slit band, placed on the median line
of the whorls, which are more angular than in PI. valida, and its peculiar ornamen-
tation sufficiently distinguish it as an independent species.

23. Pleurotomaria comata n.
Pl. IX fig. 18—19.

Shell regularly turbinated with seven ventricose whorls. Slit band placed on
the median line of the body whorl, high up near the suture on the lower whorls, con-
cave, with the bordering lines only slightly projecting, crescents microscopically mi-
nute, crowded. The ornamentation of the surface consists in densely packed, nearly
straight, threadfine lines. Aperture ovate, umbilicus open, narrow. Length 9 millim.,
breadth 7 millim. Apical angle 64°.

Occurs in the shale of Djupvik, from where the State Museum at Stockholm has
obtained several specimens.

It is nearly related to the preceding, but differs through more globose whorls,
the higher position of the slit band and the sculpture of that band, as well as that
of the surface.

24. Pleurotomaria cequilatera Wancenperc.
Pl. IX fig. 20—29.

Helicites wquilaterus 1818. Wantenpere Petrif. Svec., 73!).
1828. Tistnc. Anteckn. IV, 237.

1) The date of most of the species published by Wan LenperG must be changed to 1818 instead of 1821,
as so often has been used. His memoir »Petrificata Telluris Svecana» in the eighth volume of the »Acta

112. G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Delphinula equilatera 1829. Husincer Tableau Ed. 1, 10,
1831. Ip. Tableau Ed. 2, 8.
1831. Ip. Anteckn. 5, 113.
ERuomphalus cequilaterus 1837. Tp. Letheea, 36, tab. XI f. 8.
1841. Ip. Foérteckning, 55.
Pleurotomaria equilatera 1848. Bronn Nomenclator, 1012.
Straparollus aquilaterus 1850. D’Orpieny Prodr. I, 29.

Shell globular or disciform, with short spire of seven whorls, resembling those
of an Helix. The slit band is only a little below the middle of the body whorl, and
close to the suture, near the upper border of the other whorls. It is narrow and open
for a long way from the aperture on the body whorl. Its surface is even and the
bordering lines are lamellar, projecting. No definite sculpture is discernible owing to
its considerable narrowness. The surface of the shell is sculptured with fine, recurved
transversal lines. The whorls are somewhat flattened below the slit band, rounded on
the umbilical surface. The aperture is transversally oval, the umbilicus wide, and all
whorls visible. Diameter 45 millim., height 20 millim.

Occurs in the shale beds (a) at Wisby, in the limestone of Samsugn in Othem,
Stor Wede at Follingbo, Westéss in Hall, Kyrkberget of Wisby, Kalens Qvarn near
Wisby, the hill of Bara, Wialmsudd at Farésund and also Faré, Lutterhorn and Stor
Myr in Rute. The Mineralogical Cabinet of the University of Upsala has a specimen
collected by Professor P. T. Creve in the limestone of Slite.

There exists a great variability in this shell, especially as to the width of the
umbilicus and the height of the spire as remarkable through the figures of the typical
specimen of Wantenperc, which has been kindly lent from the Mineralogical Cabinet
of Upsala, with its low spire and flattened whorls to these globose shells delineated in
the figs. 26 and 27. Through the former, fig. 20—22, there can be no doubt of what
Wantensera really meant by his species. But there is no reason with him and Hr-
SINGER to suppose that it also has been found in the Lower Silurian. I have not
seen a single specimen from that formation appertaining to this species. In Histncrr’s
own collection there are specimens from Holmestrand in Norway, badly preserved, and
by him called Euomph. ewquilaterus. One specimen, the best, may possibly belong to
this species. In the same collection there are also specimens from Gotland called
Euomph. wquilaterus. They are five, much worn specimens of Oriostoma discors from
Kapellshamn and one specimen of Pleurotomaria undulans. Excuwarp, Leth. Rossica I,
1, 1170, adopts also this species, but the identification is questionable, as well as that
of Ksgrutr in Veiviser p. 24.

Socictatis Regis Scientiarum» was indeed printed already in 1818, as Wanienperc himself says in the
beginning of the »Additamenta» to that memoir, page 293 of the same volume. The statement there
given is: »Postquam anno 1818 impressa fuerat Commentatio de Petrificatis Svecanis» ete. The me-
moir had also been early enough distributed by its author to some geologists, as can be perceived by
what Broneniarr says in his »Crustacés fossiles» (1822) p. 2, vizo.. M. Wantenpere, dont le tra-
vail... west vent & ma connaissance quien 1819». But on the title page of volume VIII, containing
the collected memoirs and papers, the year 1821 is printed, as it was not issued complete before
that year.

KONGL. SV. VET. AKADEMIBNS HANDL. BAND. 19. N:o 6. 113

Divisio V. INCISA.

25. Pleurotomaria labrosa J. Hatt.

Pl. IX figs. 30—38.

Pleurot. labrosa 1859. J. Hatt Pal. N. York vol. III, 339, pl. 66 f. 1—5, pl. 67 f. 6.
Pleurot. balteata 1867. Linpstr6m (not Purtittps) Nomina foss. Gotl., 23.

Pleurot. labrosa var. oecidens 1868. J. Haut 20:th Rep. N. York St. Cab. I:st Ed. 345.

Pleurot. occidens 1868. Hatt 20:th Rep. I:st Ed. 364, pl. 15 (6) fig. 11—12.

1868. Ip. 20:th Rep. Revised Bd., 392, pl. XV f. 11—12, pl. XXV f. 9—10.
1875. Hatin & Wuirrietp Geol. Survey of Ohio, vol. II, 142, pl. 8 f. 2.
1877. Ogntert Bull. Soc. Geol., 585, pl. IX f. 6, 6a.

1877. Muitier American Fossils, 160.

Shell turbinated, with a short spire and the body whorl enlarged many times
the size of the other whorls. Whorls five, almost flat or horizontal beneath the large
and prominent slit band, above it convex and ventricose. This band is situated beneath
the median line of the whorls, it is oblique with the surface directed downwards; the
thin and sharp edges (fig. 35) transform it into a deep groove, somewhat wavy in its
course (fig. 33). The crescents (fig. 34) are thin, deeply incised lamella, concentrically
striated, obliquely hiding behind each other. The inferior, flat side of the whorls is
transversally striated by crowded lines of growth, which are crossed by a several ele-
vated, longitudinal strix in some specimens, while they are completely wanting in
others. The superior moiety of the whorls is ornamented by a number of spiral ribs,
which together with the longitudinal lines form a regular, cancellated trellis work.
There are also finer transverse strie. The slit in the aperture continues open for a
long distance. The aperture is rather rhomboidal and angular in the four corners,
below, above and at the sides, in the lowest corner acuminate. The exterior lip is
thin and sharp, the interior or columellar border thick, smooth and callous, folded
back tightly against the body whorl, so that no umbilicus is visible. Height 48
millim., breadth 45 mill., longitudinal diameter of the aperture 35 mill., transverse
diam. 30 mill.

It occurs in the soft shale at Wisby, at Westergarn, where the most numerous
specimens have been found, Stora Carlsé, Ejmunds, in the canal between Atlingbo
church and Hogran, Klints in Boge and Lansa in Faré. It does not occur in the lime-
stone beds above the shale.

This species is interesting in consequence of its being one of the few which
continue in the Devonian formation. It was first described by Hati from that forma-
tion and Orutert later also found it in the oldest Devonian strata of the north of
France. Its geographical range is also great, as it has been found in England, besides
in N. America and France. In England it has been found in the Wenlock Strata at
Walsall according to a specimen in the Museum of Practical Geology in London, of

K. Sy. Vet. Akad. Handl. Bd. 19. Nizo 6. 15

114 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

which Dr G. J. Hinpr kindly has sent me a cast to compare. It has often been
confounded with Pleurot. balteata Pnitiirs which is a quite different species, as I have
learnt also through a cast kindly sent from Dr Hinpr.

26. Pleurotomaria limata nom. nov.
Pl. X fig. 2—17.

Euomphalus carinatus 1839. Sowersy in Sil. Syst.. 616, pl. 6 f. 10.
1843. Morris Catal. Brit. Fossils Ed. 1, 144.
1847. Murcmison Silurian Rocks of Sweden, Qu. Journ. Geol. Soc. Lond., 29, 49.
1854. Morris Catal. 2:d Ed., 247.
1867. Satter Siluria 3:d Hd., 531, pl. 24 f. 11.
1873. Ip. Catal. Cambridge Foss., 157.
Straparollus carinatus 1850. D'Ors. Prodr. I, 29.

Shell globular with short spire or turbinated with elongated spire and ventri-
cose whorls. The former variety, figs 2—6, is from the southern localities of Gotland,
mentioned below, the later, figs. 7, 8, 10, from the northern ones. The slit band is
placed a little above the middle line or exactly on it in the body whorl, near the
upper suture on the other whorls. As to its course it follows not always the same line,
but deviates from it obliquely as seen in figure 7. It is much prominent, more so
than in any one of the preceding and nearly as much as in the following. Details of
it are given in figs. 14—17. The crescents are of a most peculiar shape, figs. 15—16,
being lamelle divided into two lobes through a large, oval slit widening backwards.
The two lobes are of unequal size, the lower one usually larger. The deep groove
in the midst between them is longitudinally as well as concentrically striated. These
lamellae have grown longer in the same proportion as both the bordering edges have
changed and, as seen in the longitudinal section fig. 17, become elongated as thin
lamella, directed obliquely towards the aperture and thinning out near the outer
margin. The slit band thus attains to a large size and in some as much as five millim.
in a transverse line. See fig. 12. In fig. 14 there is an enlarged transverse section,
in which two pairs of the lobes have been cut through.

The depressed variety has five whorls, sloping in an acute angle to the slit band.
The aperture is transversally ovate, broader than high. The surface is richly sculptured
by a great number of spiral lines, varying from three to ten or more, crossed by lines
parallel with the lines of growth. Beneath the slit band the spiral lines are more
numerous and close, forming with the transverse lines a fine trellis work of minute
meshes and points, nearly alike the surface of a fine polishing file, fig. 3, 13. The
umbilicus is either open as to show all whorls, fig. 6, or partially concealed through
the acute angle formed by the interior lip of the aperture, f. 3.

The elongated variety, figs. 7—12, from the northern localities of Gotland is
turbinate with longer spire and ventricose whorls. There is usually only one spiral
ridge above the slit band, seldom two, but much prominent. Beneath the slit band
there is a varying number from a single longitudinal line to quite as many as in the

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 115

former variety. The shell consists of two strata of which the interior one is smooth
aud glossy. The aperture is obliquely ovate, higher than broad and the umbilicus
narrow. In some, fig. 7, 8, the suture is very deep. The slit band is also placed
lower, than in the former, where it is close to the suture on the smaller whorls.
Dimensions of the lower form: height 32 milim., width 55 mill, height of aperture
15 millim. The elongated variety has in height 32 millim., breadth 35 mill., aper-
ture 21 mm.

The shorter variety is found at Klinteberg and Lilla Carlsé in the limestone
beds, in the shale beds at Wisby, Gnisvard, Westergarn and Stora Carlsé. The elon-
gated form is found in the limestone beds of Wisby, Likkershamn, in the canal near
Westéés in Hall, Samsugn in Othem, Lannaberget near Slite, Wialmsudd in Bunge,
Lutterhorn in Faré, Kalens Qvarn, Kristklint in the bay of Kapellshamn.

Pleurotomaria crenulata Mac Coy, Palewoz. Fossils p. 291, pl. 1 K. f. 45, may
also be referable to this species, but I cannot be sure of it through the description
and figure alone. There cannot be any doubt left that this species really is the E.
carinatus of Sow. since Murcuison says he also found it in Gotland and, above all,
since I have had occasion to see a cast of the original specimen of Sowerby in the
Mus. of the Geol. Soc. of London from the Aymestry Limestone at Aymestry.

Murcutson says in the »Postscript» to the paper on the Silurian Rocks of Sweden:
»Mr SowerBy is responsible for the E. carinatus, which is distinct from Inachus sul-
catus Hisincer.» This statement, even if the figure in the Silurian System did not
show the identity, must suffice to dispel the identification of this shell with Inachus
costatus or centrifugus as Morris |. c. and Bronn Nomenclator p. 478, have it.

I have been obliged to give this species a new name, as there already before
exists a Pleurotomaria carinata Sow. 1834, Mineral Conch. p. 247.

Divisio VI. ALATZs

(Euomphalopterus F. Roemer.)

27. Pleurotomaria replicata n.
Pl. XIII fig. 39—44.

Shell evolute, with lowly sunk spire, whorls three and a half, wide apart. Slit
band situated on the lower and exterior edge of the trigonal whorls, consequently directed
downwards towards the apical side, as usual with so many Pleurotomarix having this
band winglike or expanded. Like that in PI. alata it is enormously widened, figs
42—43, into an aliform lamina, nearly as long across as the widest diameter of the
whorl. The crescents closely set, elongated as lamellx, directed outwards towards the
aperture. In a section across the band, fig. 43, more than twelve crescents may be seen
cut across. A section along the exterior edge of the aliform band reveals, fig. 44,
the extreme, thin outlines of the much distantiated crescents. A section of the
whorls, fig. 39, gives the figure of a nearly isoscele triangle, the short basal line of

116 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

which is the sloping, interior umbilical side and the both equal sides are the exterior
and the apical sides. There is thus a narrow ridge running along the middle of the
umbilical side, being in older whorls as thin as a knife edge. The ornamentation con-
sists of transversal, regularly distantiated, narrow lines, somewhat wavy and enclosing
between them numerous, minute lines, parallel with them. When reaching the wing
of the slit band they are bent in a gentle curve backwards. On the umbilical side
the sculpture is more coarse and consists of imbricated lamella.

Length of whorl and slit band near the aperture 21 millim. Length of slit band
alone 10 millim. Breadth of whorl near the aperture 10 millim.

Only one specimen has hitherto been found in a detached stone on the shale
beds near Wisby, which probably, as far as can be judged by the rock, belongs to the
Upper Silurian of Gotland and the oldest shale.

This species is related to Eccyliomphalus alatus Ferp. Roemer Leth. Geogn. 1876,
tab. 5 fig. 5, in which, however, the apical spire is elevated into an apex on the wm-
bilical side, the slit band is shorter and the section of the whorls is rather more oval
than triangular. E. alatus or a nearly related species also occurs in the Upper Red Or-
thoceratite limestone of Oland, while another, which comes near to Pleurotomaria repli-
cata, has been found in the Upper Gray limestone of Dalecarlia. These fossils have
been numbered with Eccyliomphalus, but I shall further down attempt to show that
this genus cannot be retained, as it contains either evolute Pleurotomarix as this
species and kindred, or evolute Euomphali, the peculiarity of the uncoiled whorls being
in no way any characteristic sufficient enough for generic distinction, when taken alone.
This Pl. replicata is a direct development from such forms as those described with
Pl. qualteriata and connects them with the group Alatea, being probably in genetic
connection with the fourth of these Qualteriate.

28. Pleurotomaria alata Wau enserc.
Pl. X, fig. 18—82.

Cornu Ammonis levis vestigium. 1730 Brome.u, Lithogr. Svec. in Act. liter. Scient. Svec. p. 31.

Turbinites alatus 1818. WauuenserG Petref. Svec., 69. tab. LI f. 6—8.
1828. Huisincer Anteckn. 1V, 221, 237.

Turbo dlatus 1824. Konic Icones fossilium sectiles, pl. IX fig. 107.

Delphinula alata 1829. Hisrneer Tableau ed. 1, 10.

1831. Ip. Anteckn. V, 113.
1831. Ip. Tabl: ed. 2, 8;

Huomphalus alatus 1829. Broneniarr Tableau des terrains, 428.
1837. Huistneer Lethea, 36, tab. XI f. 7 a—b.
1839. AnGeLIn Museum Paleontologicum Scandinav. N:o 30.
1839. Sowerby Sil. Syst., 631, pl. 13 f. 28.
1841. Hutstneer Forteckn., 55.

1843. Morris Brit. Fossils, Ed. 1, 144.

1847. Murcutson Quart. Journ. Geol. Soc., 29.
1848. Bronn Nomenclator, 478.

1848. Purtries Mem. Geol. Survey II, 1, 356.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. wN:0 6. 117

Euomphalus alatus 1854. Morris Brit. Fossils Ed. 2, 247.
1855. Pieter Traité de Pal. III, 155, pl. LXII f. 12.
1862. Mac Coy Synopsis Sil. Foss. Ireland, 13.
1867. Sauter Siluria 3 Ed., 531, pl. 25 f. 4.
1867. Linpsrrom Nomina foss. Gotl., 23.
1867. Quensrept Handbuch der Petrefaktenkunde, 506, tab. 45 f. 64.
1868. Bressy Thesaurus Siluricus, 153.
21871. Baty Figures of Characteristic British Fossils pt. III, pl. 21 f. 7 (scarcely).
1873. Sauter Cat. Cambr. Mus., 157.
1882. QuensteptT Petrefaktenkunde Deutschlands 1:e Abth. 7:e Bd., 327, tab. 197 f. 41
Schizostoma alatum 1842, D’Arcuiac & Vern. Trans. Geol. Soc. Lond. 2:d Ser. vol. VI, 365.
Straparollus alatus 1850. D’Orsiany Prodr. I, 29.
Pleurotomaria alata 1858. Fr. Scumipr Esthland, 201.
Euomphalopterus alatus 1876. Ferp. Roemer Leth. Geogn. tab. 14 f. 9a—9b.

Shell turbinate, spire broad and short, consisting of six or seven tubular whorls,
circular in section, fig. 29. The slit band is placed above the median line of the
whorl, nearly on a level with the upper edge of the aperture. This large, lamellar
slit band, which is built on an exactly homologous plan with that of Pleur. replicata
and Pl. limata, occupies a belt around the shell, which on the last whorl attains a
length across of 12 millm. in the largest specimens, the whole diameter being 50 mm.
It is directed at first obliquely upwards, fig. 29, 30, and turns at the exterior edge
abruptedly downwards in a curve, which sometimes has the appearance of a hook, f. 30,
32. Along its outermost margins this lamina is in some specimens folded in undulations
f. 24. If this large slit band be split in two halves along its median line, it is found
on each side to consists of two thin strata (f. 27) the exterior one transversally stria-
ted on its surface and the interior one quite smooth and transparent. Within these
are enclosed the crescentic laminw and through their development the space between
the bordering laminew seems to be divided into a number of narrow compartments
(fig. 27, the enlarged portion). They are wider apart near their exterior ends and
converging towards the whorls. When the slit band is sectioned transversally across
these crescents the appearance shown in fig. 30 is produced. The curved outlines of
ten obliquely sectioned, crescentic lamelle are seen in the dark shale between the
bordering edges of the slit band. These enclosing lamelle are in direct continuation
with the exterior darker stratum of the shell, composed of minute, angular lamina.
Within this exterior stratum another of clear crystalline calcite lies, often retaining a
nacreous lustre. There are absolutely no communications, nor perforations or tubes
between the interior cavity of the whorls and the spaces separating the crescentic lamella
of the slitband as Frrp. Rozmer has supposed. The interior cavity is closed as in
other Pleurotomarie. Along the exterior edge of the slit band, fig. 31, the ends of
the crescents are discerned, especially when a little cut; the thin edges of the band
are usually broken on the older whorls, f. 22.

The umbilical side of the shell is nearly cup shaped, being hemmed in around
the edges by the high, turned up slit band and sunk towards the umbilicus, around
which there is an elevation.

The surface is only transversally striated, the stria running straight down to
the slit band and, chiefly on the umbilical side, directed towards the aperture and

118 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

at the very edge of the laminal slit band turning back from the aperture, quite
as is the case in all Pleurotomarix with transverse stria on the surface. The small-
ness of the apertural slit in this and similar species causes this dissimilarity from
the other Pleurotomarix. Around the umbilicus a small ridge is running, a little
knotty where the transverse lines cross it. On the spire the transverse lines are more
distantiated, elevated, and formed by the lines of growth. The aperture is circular,
the lips sharp and thin, not reflexed, the exterior one extending into a triangular ap-
pendix, a narrow groove, representing the sinus or the slit, which here is reduced to a
minimum. The umbilical side of the aperture is deeply insinuated, almost as much as
in some of the Devonian shells which D’Arcutac and Verneui have placed in the
genus Schizostoma, Sch. radiata for instance, but which probably are different from
Brony’s Schizostoma. The umbilicus is very wide and open and all whorls are seen
to the bottom of the umbilical funnel. On the umbilical side of the slit band there
are in some specimens discerned two or three darker spiral bands, a little deepened
in the shell, somewhat reminding of rests of colour bands.

Largest specimen 26 iillim. in height, 5! millim. in breadth. Another specimen
attains 18 millim. in height, 35 millim. 1 breadth, the umbilicus has 9 millim. in dia-
meter and the slit band is 7 mill. wide across.

This characteristic species has been found in numerous specimens in almost all
strata of Gotland, in the shale beds of Wisby, Westergarn and Slite, in the limestone
of Lutterhorn and Lansa of Faré, of Slite, Samsugn in Othem, Klinteberg, Westdés in
Hall, Kylley, Kalens Qvarn, Stora Carlsé, the canal of Atlingbo.

This species has by Ferp. Roemer been made the type of a new genus Kuom-
phalopterus, which is characterized by tubular perforations through the lamellar edge,
which surrounds the shell, and also penetrate through the walls of the shell into the
interior of the whorls. But, as stated above, there do not exist any such perforations
in the walls of this shell and the tubes are, as shown above, nothing but the spaces
between the lamellar crescents of the slit band. Nor has ever any operculum been
found to this species‘) or to other Pleurotomariz. There is consequently, not any reason
to place this in a new genus, at the highest this and the following ones may form a
subgenus to Pleurotomaria.

29. Pleurotomaria alata var. subcarinata.
Pl. X fig. 33—37.

This small variety differs chiefly in having an obtuse ridge beneath the slit band,
and where it runs, the whorls are angular, while in Pl. alata, figs. 18, 19, the whorls
are rounded on the corresponding surface. There is a revolving ridge around the um-
bilicus in this, as well as in the principal form, though not in all specimens. There
is no reason to consider this as more than a variety of the former, as there are some

') See Zivren Handbuch der Paleontologie Bd. 1, 2 Abth. p. 206, where he describes an operculum of
Kuomphalopterus, but which in reality belongs to some Oriostoma.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o0 6. 119

few specimens of Pl. alata, fig. 28, which also show a very faint rib nearly on the same
place as in the variety. Height 8 millim.; breadth 16 mill.

From Djupvik in Eksta, Lingsarfve in Nas, Faré, Westergarn and in the oolitic
limestone of Bursvik.

30. Pleurotomaria alata var. opposita n.
Pl. X. fig. 38—40.

Shell trochiform, broader than high, spire of five or six whorls, more ventricose
than in the preceding varieties of the species. Slit band situated a little above the me-
dian line of the whorls. Beneath the band, near the suture, a narrow keel is seen and
there is none around the umbilicus. This variety is best distinguished by the direc-
tion of the transverse striw, which, as seen in fig. 39, are more prominent and elevated
than in the others and are obliquely turned against the aperture, quite opposite to
what obtains in most of the other Pleurotomarix. The ends of the larger strix radiate
in an expanded brush of minute strim, fig. 40. In the preceding forms the strix meet
the slit band either rectangularly or directed backwards. Height 7 mill., breadth 15 mill.

From the shale at Petesvik in Habblingbo.

31. Pleurotomaria pretexta n.
Pl. XI fig. 1—7.

Shell trochiform, moderately elongated, with six whorls, which are convex and
evenly rounded below, the umbilical side almost flat. The keel formed by the slit
band is broad, near its junction with the whorls on both sides ornamented with a
strongly prominent, spiral ridge, on which the transverse stria form nodules. The band
is placed a little above the median line of the body whorl and on the other whorls
high up, close to the suture. As seen in fig. 5 its interior crescentic lamella are very
closely packed, elongated and reach obliquely forwards to the margin of the keel. This
margin, fig. 6, is sometimes folded in a number of small wavelets, nearly as in
Pl. undulans though more regularly. The transverse striw of the surface are ap-
proached, although at regular distances, and have some smaller, parallel ones in the
interstices. The aperture is circular and a little angular in its interior corner and the
umbilicus open and narrow. Height 13 mill., breadth 16 mill, aperture 6 millim., um-
bilicus 3 millim.

Occurs in the lowest shale beds near Wisby.

This species is nearly related to Pl. alata, from which it is readily distinguished
by the elevated ridges near the edge of the slit band.

32. Pleurotomaria togata n.
Pl. XI fig. 8—13.

Shell trochiform of seven angular whorls, slit band thick and short, fig. 15,
placed above the median line of the body whorl and close below the suture in the

120 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

other whorls. It shows in the margin, fig. 12, the ends of the enclosed crescents,
which are formed upon the same plan as in the other »Alate». In a transversal sec-
tion, fig. 13, the uncommonly thick shell substance of the bordering lines encloses a
most narrow slit band. Beneath the slit band an angular ridge is seen and below that
the wall slopes abruptedly inwards to the suture. The surface is transversally divided
into large sinuous folds, the interstices being streaked with minute, parallel lines, fig.
12. The umbilical side, fig. 10, is comparatively smooth and glossy, the transverse lines
being most conspicuous near the margin, where, a little inwards, a blunt rib runs pa-
rallel with it, corresponding to a similar one on the lower side, though not so distinct.
Another ridge, more distinct, encircles the umbilicus, which is open, but narrow. The
aperture is circular as well as the section of the whorls, the lips are thin and sharp-
edged without being reflexed.

Dimensions of the specimen figured: height 12 millim., breadth 20 mill, aperture
te TMU

Several species are found in the shale beds of Wisby and Petesvik in Habblingbo.

33. Pleurotomaria frenata n.
PL Xai tips iA.

Shell turbinate of five ventricose whorls. Slit band situated only a little above
the median line of the whorls, its keel is short, of triangular section, with broad base
of plaited folds, fig. 14, with angular ends. The crescents of the band are as wide
apart at their ends as in the other species. The surface on both sides is covered by
fine, minute striw, wavy and interlacing, forming a reticulate surface like that of the next
species. The striae are directed towards the aperture and turn backwards only on
the slit band. The aperture is regularly circular with thin, sharp lips, the wmbilicus
iS open.

Dimensions. Height 19 millim., breadth 26 mill., aperture 11 millim. Five spe-
cimens have been found in the shale beds near Wisby.

This species is intermediate between Pleurot. praetexta and Pleur. undulans, uni-
ting a slit band like that of the former with an ornamentation resembling that of the
latter.

34. Pleurotomaria undulans pn.
Pl. XI. fig. 15—23.

Kuomph. equilaterus 1867. Linpstr. Nomina, 23.

Shell helicoid, thin and fragile, and consequently usually crushed and distorted, spire
short, whorls six, ventricose. Slit band situated nearly on the middle line of the body
whorl, on the other whorls close to the upper suture, which it covers, very narrow and
often enlargened into a thin lamina, which is bent and folded into a succession of irregular
waves, as delineated in the figures. Its interior structure coincides entirely with that

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 121

of the others in this group. Fig. 23 represents it sectioned across with some ten cre-
scentic lamella obliquely cut, and fig. 22 is a section rectangular to the former. In
fig. 21 a magnified portion of a cloven band is delineated, where in the interior the
elongated, crescentic lamella are directed obliquely, diverging outwards. The whorls are
beneath the slit band rounded and covered by fine, threadlike, elevated striw, equally
distantiated. Above the slit band the transverse striz are still finer and more numerous
and a little sinuous. The striw are directed towards the aperture till they reach the
slit band lamina, on which they turn backwards. The aperture is transversally ovate,
almost twice as broad as high and the lips thin and sharp. The umbilicus is open
and measures nearly a third part of the diameter. Some specimens still retain the
nacreous lustre very vividly on the nucleus. A nucleus, fig. 20, shows traces of a ridge
around the umbilicus, which, however, has not been observed on the outside of the
more complete specimens. But this, as well as similar impressions on the inferior
surface of the whorls may be due to the crushing of the specimen. Height 20
millim., breadth 28 mill., breadth of the umbilicus 9 mill. in a shell having 25
millim. in a transverse line.

Found in the shale and limestone in the vicinity of Wisby, and also in south
along the coast in the shale at Gnisvird and Westergarn and in north as far as the

shale of Halls huk.

35. Pleurotomaria Marklini n.
Pl. XI, f. 24—26.

Shell trochiform, nearly flat on the umbilical side. Whorls six with even sides.
Slit band placed a little above the median line of the whorls, thin and folded in ir-
regular wavy curves. The sculpture consists in transverse, oblique lines, which on the
umbilical side are coarse, callous ridges. Aperture obliquely ovate, umbilicus open,
but narrow. Height 14 mill., br. 18 millim, aperture in height 6 mill., breadth 7 mill.

Three specimens have been found in the limestone of Klinteberg and the figured
one is from the Marklinian Collection in Upsala.

36. Pleurotomaria cirrhosa n.
Bl Xd 2729, ple XU, fig, 13,

Shell large, trochiform, nearly flat on the umbilical side, whorls seven, modera-
tely convex. Slit band situated a little above the median line of the whorls, forming
an extremely thin lamina with narrow edge. It is folded regularly and transversally
by grooves parallel with the transverse stri~ and in the older whorls its broken
margins have coalesced with the surface of the next younger whorl. The ornamenta-
tion on both sides of the band consists of gently curved strix, turning backwards from
the aperture and meeting in an acute angle at the slit band. The interstices between

the strive are crossed by short, irregular, unconnected lines between which the surface
K. Vet, Akad. Handl. Band 19. Nio 6 16

122 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

is deepened, and thence having a pitted aspect. The aperture is obliquely elliptical,
broader than high. The lips seem to have been thin, not reflexed. The umbilicus is
open and wide and all whorls are visible inside.

Height 55 mill., breadth 1,1 decim. Body whorl near the aperture 52 mill. across.

About eight specimens of this large shell have been found in the lower lime-
stone strata of Ostergarn and a smaller in the uppermost limestone of Linde klint.

As the specimens found are mostly nuclei and only few traces or shreds of the
shell are left, there may be some doubt if this species belongs to Pleurotomaria. But
the direction of the transverse striae seem to warrant such a supposition, even if there
is no certain evidence in the section of the very thin slit band lamella, pl. XI fig. 28.

Divisio VI. PLANORBIFORMES.

37. Pleurotomaria planorbis Hisincer.
Pl. XIX fig. 30—39.

Turbinites centrifugus 1828. Histncer (not WaHLENBERG). Anteckn. IV, 221, 237, tab. VI f. 2.
Helicites? centrifugus 1828. Ip. Ibid. in the explan. of the figures.
Euomphalus centrifugus 1829. Ip. Tableau, ed. 1, 10.
1831. Ip. Anteckn. V, 114, tab. 1 fig. d.
1831. Ip. Tableau, 9.
1848. Bronn. Nomenlator, 478.
1854. Morris. Catal. Brit. Foss. Sec. Ed., 247.
1855. Mac Coy. Paleozoic Fossils, 297.
1867. Sauter, Siluria, 231, 531.
1873. Ip. Catal. Cambr. Foss., 156, 172.
1876. Ferrp. Roemer, Lethea Geogn. Taf. 14 f. 13.
Euomphalus substriatus 1829. Histncer Tableau ed. 1, 11.
1831, Ip. Anteckn. V., 114. Tab. 1 fig. e:
1831. Ip. Tableau ed. 2, 9.
Centrifugus planorbis 1835. Hrsineer, according to Bronn Leth. geogn. Ed. 1, Bd. 1, 97.
1848. Bronn Nomenclator, 256.
Tnachus sulcatus 1837. Huis. Lethea Suec., 38, tab. XII f. 1 a—e.
1841. In. Forteckn., 55.
1867. Linpstr. Nomina, 29.
1882. Quensrevt Petrefaktenkunde Deutschlands 1e Abtheil. 7r Bd., 395, tab. 200
fig. 81.
Straparollus sulcatus 1850. D’Orsieny Prodr., 30.

Shell disciform, with five whorls, rapidly increasing in size in the following ratio.
Body whorl 22 mill., in breadth.

9 wil » »
3 Srp »
4 3 » »
5 2 » »

The slit is at first large and broad and forms, where it ends, a narrow, acute
angle. It, as well as its continuation, the slit band, is situated on the apical side of
the shell, close to the suture as in the following species. It is comparatively nar-
row, elevated above the surface as a thin string and included only by the straight ed-
ges of the shell, though in a few instances there are obscure traces of bordering lines.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. Zo

The crescents vary as to their shape, as may be seen by the figures, being commonly
dense, regular and distantiated or thick and oblique with the greatest bend near the
outer lip. But then there are specimens showing, at least for some distance, an angu-
larity in the transverse striw instead of the slit band, a conformation quite resembling
that which prevails amongst the Euomphalida and of which also traces are seen in
some of the Murchisoniz.

The whorls are nearly tubular or quite as much rounded on the umbilical as on
the apical side although they in some instances seem to be somewhat more flattened on
the umbilical side. On the apical side there are on the body whorl about fourteen
narrow, longitudinal keels, alternately larger and smaller. The uppermost one, which
separates both faces, is the largest of all, blunt and horizontally outstanding. These
keels are crossed by regular, elevated, threadlike strix, between which are others still
more minute and fine. These meet the slit band on both sides as usual in an acute
angle directed backwards. On the umbilical side there are dense, fine, transversal
strie, bent in a great curve backwards, and then, near the keel, forwards. In some
specimens there are as many as seven low, only slightly, elevated, longitudinal keels,
which are more distinct in the young specimens than in the older ones. In these usually
no keels at all are visible.

The three oldest whorls are filled with an organic deposit of a solid, calcareous
mass, ending in a concave surface, without any sign of diaphragms. In most specimens
this apex is often deciduous. The interior whorls are tightly enclosed by the exterior
ones, the longitudinal keels of all being interlocked with each other in the interstitial
grooves. The whorls have never been found disjointed, though this seems to have
been the impression of Hismncrr, probably owing its origin to the observation of the
nucleus alone, when the uncommonly thick shell bad been removed.

The aperture is circular, approaching to transversally elliptic, its outer lip being
more prominent and protruding, sloping inwards in a gentle sigmoid insinuation.

Greatest diameter 66 millim. Height of body whorl 22 millim.

This shell has been found chiefly in the lowest, marly shale beds of Gotland, in
numerous specimens, well preserved, at Grogarn and other places of Ostergarn, in the
limestone beds of Ardre, and also in the shale of Fardhem, Wisne myr, on which the
limestone beds of Sandarfve and Linde repose. From the limestone strata of Oster-
garn a single specimen has been obtained.

Histncer and Bronn considered this very characteristic shell so much distinct
from the so called Euomphali, with which it commonly had been placed, as to create
for its reception new genera. It seems that the former in a letter to Broyn in 1835
proposed to name it Centrifugus*) led by a mistaken notion that this fossil was iden-
tical with the Turbinites centrifugus of WAHLENBERG”), which cannot be the case, as that
shell rather, as far as can be judged, is either a Pleurotomaria of the evolute form or
an evolute Euomphalus, of which both genera there have been specimens found in the
Orthoceratite Limestone of Dalecarlia, the only stratum from which WAHLENBERG cites

1) Nomenclator p. 256.
?) Petrificata Telluris Svecane p. 71.

124 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

his Centrifugus. He does not anywhere mention it as found in Gotland. I cannot,
however, find that Hismvcrr himself ever in his published writings made any use of
the generic name Centrifugus. It occurs only with Bronn for the first time in Lethea
geognostica ed. 1, Bd I p. 97, which part of the volume was published already in
1835 as may be concluded by referring to the half yearly Catalogue of the German
booksellers for that year. This genus included Centrif. costatus His., the type speci-
men of which is kept in the Cabinet of the School at Wisby and certainly is the shell
of a Cephalopodan, probably a Trochoceras. The second species which Bronn names, C.
planorbis, is identical with the sulcatus of Hisincer as can be seen by Bronns Nomen-
clator p. 256"). But already in 1837 in the Lethwa Suecica Hisincer gave it the
name Inachus. As this name in 1798 had been bestowed on a crustacean by FAsrictus,
it could not be retained even if the fossil did form an independent genus. The pre-
sence of the characteristic slit band, which has not been before observed *), at once
settles the question of its systematic place. It must, however, be conceded, as has
been pointed out above in the description, that there are some features in the position
and structure of the band, which remind of Euomphalus. It seems that De Koninck,
Faune Carbonif. de Belgique II, partie II p. 107, intended to give this species the
generic name Polytropis instead of Inachus, but as he is citing Kuomph. dicors as the
typical species, the name Polytropis must be identified with Oriostoma, of which
see below.

In 1831 Hisivcer gave the figure of his Euomph. substriatus, Anteckningar V
tab. I fig. e, which as far as can be seen, without access to the unknown type speci-
men, is a species of Trochoceras found at Faré. He, however, in the Lethaa unites
this form with In. sulcatus, giving it as the umbilical side. Now a glance on the ci-
ted tab. I fig. d § e, is convincing that both «@ and e are apical sides of different shells
and he must himself have been aware thereof, as the latter figure in the Lethxa is
drawn in a reversed position, so as to match the apical side.

EKuomphalus carinatus, Sowrersy, identical with the Pleurotomaria described above
as P. limata, has also by some English authors been confounded with Pl. planorbis,
but it is certainly distinct from it as Murcuison*) also conceded and as has been more
particularly stated above.

’

38. Pleurotomaria helicina nv.
Pl. XI figs. 34—37.

Shell discoid, with short, nearly flat spire of five whorls. The slit band is large,
placed beneath the median line of the body whorl, hidden from view on the other
whorls through the covering, lower edge of the next whorls. The crescents are obscure,
distantiated. The surface is smooth and glossy with some few, indistinct transverse
grooves and lines of growth, which are curved backwards. The aperture is nearly

1) »Hisineer 1835 in litteris» he says 1. e.

*) In Quensrep1’s Petrefaktenkunde Deutschlands 1:e Abth. 7:r Bd. pl. 200 f. 81 a good delineation
shows the slit band, but this has not been remarked by him in the letterpress.

3) Qu. Journ. Geol. Soc. 1847 in the Postscript p. 1 to »Silurian Rocks of Sweden».

KONGL. SV. VET. AKADEMIENS HANDL BAND. (9. N:0 6. 125

circular with thin lips. The peristome is interrupted. The umbilicus is open and
wide, showing all the interior whorls. It is accompanied by a spiral groove near the
interior border of the whorls.

Height 5 millim., breadth 16 iill.

Occurs plentifully in the shale beds of Djupvik in Eksta and has also been found
in a few specimens in the shale of Wisby.

As to its depressed spire and the position of the slit band this species resembles
very much some Devonian Schizostomata figured by Gotpruss in his Petref. Germanix,
plate 188 figs 4—-6.

Divisio VIII. NATICOIDEZ.

39. Pleurotomaria exquisita n.
Pl. XI, figs. 30—33. .

Shell ovato-globose, naticoid, glossy, with five ventricose whorls, of which the
body whorl many times surpasses the others in size. The slit band is situated above
the median line of the body whorl and is in the others completely hidden under the
covering lower edge of the superjacent whorl. It is comparatively large, on a level
with the other surface and enclosed by a fine, distinct line on each side and crossed by
irregularly distantiated, linear crescents, which are a little oblique, fig. 32. Some three
or four shallow grooves run rectangularly to these along the median line of the band.
The transverse lines of growth are bent in curves directed from the aperture back-
wards, those above the slit band being more curved than the others. In the opposite
direction, obliquely crossing them, almost microscopically minute striw are seen, on
both sides of the slit band, as well as on this band. Those above the slit band do
not cross its superior bordering line, but follow it in a highly acute angle, densely
packed. They are sinuous and bifurcated. Those on the slit band are in direct con-
tinuation with those below, which are sinuous without bifurcation, more distantiated
and more oblique. The suture is so shallow, that the whorls on both sides of it form
nearly an even line. The aperture is obliquely elongated, longer than broad, the lips
are thin, the inner one reflexed around the umbilicus, which is of moderate size.

Dimensions: height 9 millim., breadth nearly 10 mm.

This beautiful little shell, one of the most remarkable through its peculiar orna-
mentation, has been found in numerous specimens in the shale beds of Djupvik in
Eksta. There is probably also a specimen from the shale of Wisby.

Gen. MURCHISONIA D’Arcurac & Verneuin.
1841. Murchisonia D’Arcutiac & Vern. Bull. Soe. Geol. XII p. 154.
1859. Hormotoma Sauter Canad. Organ. Remains Dec. [ p. 18.
Shell elongated turriculate, whorls numerous, slowly increasing in size, oldest whorls
filled with organic deposit of calcareous matter. Slit band and ornamentation as in Pleu-
rotomaria. Nacreous lustre not observed.

126 G. LINDTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

It is very difficult to find any characteristics wherewith to distinguish those
forms called Murchisonia in a ready manner from Pleurotomaria. According to the
authors of this genus the aperture should be »terminée a sa base par un canal trés
court ou tronqué>. But in several Pleurotomariw the superior corner of the aperture
may also be seen to be protracted in an angle. Sauer in Canad. Org. Remains, vol. I
p- 18 divides this genus in Murchisonia proper with acutely carinated whorls and
Hormotoma with beaded, rounded whorls and rounded aperture. But while then in
the former genus many Pleurotomarix with broad spire have been included, it is more
practical with Bronn to include all banded shells with elongated and slender spire of
many whorls whether carinated and ornamented or plain, in Murchisonia and consider
it as a subgenus merely to Pleurotomaria.

This genus occurs as early as in the Bala limestone of the Cambrian formation,
according to Sauter, Catal. Cambr. Foss. p. 68, and continued through all Paleozoic
formations, while in the Mesozoic ones no such elongated Pleurotomariz are known with
any degree of certainty. With us in Sweden they are scarce in the Lower Silurian,
a large species, related to the Esthonian M. insignis Ercuw., having been found in a few
specimens at Grasgard and Segersta in Oland in the uppermost limestone beds. In the
Upper Silurian, again, of Gotland they are numerous and especially there are nuclei of
such elongately whorled forms, which also may be Loxonemata, filling the strata in
several places. Of some species the shell has always been destroyed and they are known
only by the impression of it in the rock. This is very strange as the shell of the nearly
related Pleurotomarie is often well preserved in the same strata. The slit band is built
upon the same plan as in Pleurotomaria. In Murchis. deflexa there is a peculiar devia-
tion, as described in detail further down, when the superior margin attains so large a
development that it, in its downward growth, hides the band. In M. attenuata the slit
band is changed, on the body whorl, into a ridge, on which the apex of the angular
transverse lines rests, quite as in the Euomphalide.

As there, at least in the first division of this genus, is a certain similar uni-
formity prevailing in the ornamentation of the shell, the position of the slit band,
the sbape and the size of the whorls, these will be the chief characteristics for distin-
guishing the various species. The genus may be fitly divided in two groups.

Divisio I. SIMPLICES.

Ornamentation uniform of backwards directed stria meeting the generally large
slit band in an acute angle; position of the band and shape and size of the whorls
giving the characteristics.

1. M. cingulata His.
2. M. cava n.

3. M. moniliformis n.
4. M. obtusangula n.
5. M. subplicata n.

6. M. compressa n.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 127

7. M. attenuata His.
8. M. paradoxa n.

Divisio Il. ORNATA.,
Shell more or less richly ornated, slit band enclosed by one or more variously
sculptured bordering lines. Almost all very small species.

9. M. erispa n.

10. M. munda n.

11. M. tortuosa n.

12. M. imbricata n.
M. cancellata n.

14. M. cochleata n.
M. deflexa n.

Divisio I. SIMPLICES.

1. Murchisonia cingulata His.
Pl. XII fig. 9—10.

?Turbinites levis major ete. 1738 Bromexi Lithogr. Svec. in Acta Lit. Svecie vol. III p. 37.

Turritella cingulata 1829. Hisincer p. p. Tableau ed. 1, 11.
1831. Ip. p. p. Anteckn. V, 115, tab. II f. 1.
1831. Ip. p. p. Tableau ed. 2, 9.
1837. Ip. p. p. Letha, 39, tab. XII, f. 6 a.
1841. Ip. Férteckning, 561).
Murchisonia cingulata 1841. D’Arcuiac & VerRNeEvIL Bull. Soc. Géol. de France vol. XII, 159.
1867. Linpsrrom Nomina, 23.
Terebra? sinuosa 1848. Sauter Mem. Geol. Survey II pt. 1, 357, pl. 14 f. 2.

Again, the following synonyms do not belong to this species.

Murchisonia cingulata M Coy Paleozoic Fossils, 293.

Satter Cambr. Catal., 172.

M’Coy Sil. Foss. Ireland, 6.

KygERULF Veiviser, 29.

Murca. Vern. & Keys. Russia, vol. II, 339.

Krause Zeitschr. d. deutsch. Geol. Ges. 1877, 22.

Kiesow Ueber silurische und devonische Geschicbe Westpreussens 1884, 58.
Pleurotomaria cingulata Bucu Beitr. zur Gebirgskunde von Russland, 116.

EtcuwaLp Leth. rossica I, 2, 1166, pl. 43 f. 2.

Shell elongate, turreted, rather slowly increasing, whorls seven, almost conical,
slightly ventricose and with shallow suture. Slit band 3 millims. wide, situated above
the middle of the body whorl and on the other whorls near the upper suture, at a
level with the surface of the shell, the crescents small and narrow, very dense. The
ornamental lines are transversal, uniform, dense, turned in a highly acute angle towards
the slit band. The aperture is ovate, higher than broad. The umbilicus is very nar-
row and nearly hidden by a reflexion of the columellar lip.

1) In a foot-note to this Histncer added: (Pleurotomaria?)

128 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Height 63 mill., width of body whorl 28 mill., width of smallest whorl 7 mill. .
Height of aperture 19 mill., width of the same 15 mill. Apical angle 36 °.

The original specimen of Hisincer, now figured anew, pl. XII f. 9, has been
found by him in a detached stone near the church of Gothem. The rock is a
variety of oolite, peculiar to a quarry at the base of Bara backe and consequently
there cannot be any doubt of its being derived from that place. Quite similar
specimens have been found in the gritty limestone near Gothems hammar. Those
from neighbouring quarries in Hoérsne are also nearly allied, though there is some little
difference as to the relative size of the whorls.

Fragments of a fine specimen have been obtained from the canal near Westdis
in Hall. Nuclei which in all probability belong to this species to judge from their
shape, have been found in the hard shale of Petesvik in Habblingbo. They are larger
than those from Gothem measuring as much as 35 mill. in width of the body whorl.
The Museum of Copenhagen has specimens from Nias.

2. Murchisonia cava n.
Pl. XII fig. 4.

Shell cylindrical, turreted, whorls, only six left in the fragmentary specimens,
ventricose, rather angular near the slit band. This is narrow, situated exactly on the
middle of the body whorl and near the upper suture in the other whorls, more deeply
excavated than in any other species of its group, the crescents oblique, distantiated.
Aperture ovate. Dimensions of specimen from Djupvik in Eksta: h. 51 mm., br. 28 mm.
Specimens have been obtained from Martebo, Djupvik in Eksta, Hérsne and the lime-
stone near Wisby.

3. Murchisonia moniliformis pn.
Pl. XII fig. 5—6.

Shell tapering, turreted, narrow in proportion to its length. Whorls eleven,
globose, with deep suture, rapidly increasing in size. Slit band nearly in the middle
of the whorls or a little above it, slightly concave. Aperture ovate, with lips much
reflexed both near the columella and in the superior border. Umbilicus hidden through
the reflexion of the columellar lip.

Length 56 millim., breadth 11 mill., apical angle 22°.

From the sandstone and the oolite of Bursvik, where it is common.

4. Murchisonia obtusangula np.
PL oly fio ez al deaaleoe

Shell turreted, moderately tapering, with twelve ventricose whorls widened on
the middle in an obtuse angle, where the elevated slit band is situated. The aperture
ovate. The umbilicus is hidden through a fold of the columellar lip. Ornamentation
in this and the two preceding species almost the same as in M. cingulata.

Height 30 mill., br. 10 mill. Apical angle 29°.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. 129

The typical specimens are derived from the limestone beds of Kyrkberget (Rackar-
backen) in Wisby. Others are from Lummelund, Samsugn in Othem, Lutterhorn in
Faré, and some specimens from Wialmsudd may perhaps also belong here. Those
from Samsugn, fig. 11—12, are much altered through corrosion and in some there is
a false appearance as if the slit band were lineated longitudinally, but this may on
closer inspection and comparison be traced to changes after the fossilization. These
specimens, however, are somewhat less angular than those from the other localities.

5. Murchisonia subplicata n.
Pl. XII fig. 8.

Shell short and thick in comparison with its congeners. Whorls nine, slowly
increasing, widened on the middle into an obtuse ridge where the shallow slit band
is placed. The inferior border of the whorls is folded into a callous ridge, which
overlies and partially covers the deep and narrow suture. The aperture is ovate, the
inner lip reflexed and the umbilicus a narrow fissure.

Height 27 millim., breadth 21 mill., apical angle 35 °.

In all, six specimens have been obtained from Lummelund in the superior limestone.

6. Murchisonia compressa n.
BMW es dip — 19:
»Turritella? (Turbo L.)» 1828. Hisineer Anteckningar IV, 221, tab. VI f. 3.
Turritella cingulata 1831. In. p. p. Anteckn. V, 115, tab. II f. 1 (nucleus).

1837. Ip. p. p. Lethea Suec., 39, tab. XII fig. 6b.
»Stenkirnor af Turritellers 1841. Ip. Foérteckning, 56.

Shell elongately turriculate, with slowly tapering whorls, only moderately ven-
tricose, numerous — as many as 18 have been numbered in one specimen. The ratio
of the increase in the whorls is in this species much slower than in any other, the
breadth augmenting much faster than the height, as is made evident through the follow-
ing comparative table of the dimensions of the whorls in five species.

M. cingulata. M. cava. M. compressa. M. attenuata. M. obtusangula.
Two specimens.
Spec. A. Spec. B.
Height of whorls. Breadth. H. Br. IL. Br. H. Br. H. Br. A. Br.

Body whorl 17mm. 31mm. 12mm. 22mm. 9mm. 20mm. 17mm. 20mm. 18mm. 22mm. 7mm. 11mm.

Pee me [Er a as 10 » 19> 8 » kS oy Lo» 15 » 17 » 18 » 6 » 9 »
Fs ie OL Oi. 18. > Si: 15 » 7h ean li ay 10 » 12 » 12 » Ape 4 » 8 »
AM. Tene Ta? » — = ee ts at ane Sy) 6 » 10 » 9 » tin ow 3 » 6 »
iy Perse — — —_— — 6» 13» ho» — 6 » — 3» De
Gan ee —_ — — a 5 » 12 » D9 » AD
(tr Ea Spe —_ —— — _— 5 » 10 » os 3 »
Srl bees m ssa — — — aes 4 » 9 » — = — — 1 » Aw Ay
Oe ks . » _— 4 » 8 » — — —— = — —

i ILO} Gee, Ne same a — — — 8 » aed) == —— — — — —

ALLE 1 a KS thie) 6 » — —— — = — —s

LO Bees — — —_ ae 3.» 6 » — —= =

K. Vet. Akad. Handl. Band 19. N:o 6 17

130 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTERORODA OF GOTLAND.

The apex of the spire is in all specimens, which have been investigated, filled
up with solid calcareous spar of a brownish colour, without any trace of transverse
diaphragmata. The nuclei have a glossy surface and look as if the interior walls of
the shell had been porcellanous. The slit band is prominent a little above the middle
of the whorls, it is narrow and slightly concave along its median line. The aperture
is rather obovate approaching to the cireular. The umbilicus seems to have been
large and open as shown by longitudinal sections when there is no compact columella
(fig. 18), but an open tubular axis interiorly.

Very frequent in the inferior limestone of Ostergarn at Grogarn and Katt-
hammarsvik, but almost only as nuclei, on which traces of the sculpture of the shell
are visible. It has also been found in the neighbouring strata of Kraklingbo and
Ardre, and it is probable that some nuclei from the limestone of Wisby belong to
this species.

Height 80 millim., breadth 21 mill., apical angle 22°.

This common species has usually been confounded with Murch. cingulata, as
Hisincer himself did, till he in his »Férteckning ofver Svenska petrificatery, edited 1841,
p. 56, separates it from M. cingulata, without giving it any new name.

7. Murchisonia attenuata Hisincer.
Pl. XII fig. 20—24.

Turbinis marini nucleus lapideus levis ete. Brometi Act. Lit. Suec. 1738 vol. UI p. 37.

Turritella attenuata 1840. His. Leth. Suec. Supplem. Secundum, 4. tab. 37 f. 7.
1841. Ip. Foérteckning, 56.
1848. Bronn Nomenclator, 1351.
Murchisonia attenuata 1867. Linpstré6mM Nomina foss. Gotl., 23 (nee. Murchisonia attenuata Hai 1856,
Trans. Albany Instit. vol. IV, 27).

Shell elongate, whorls seven in the most complete specimens, though there have
certainly been many more. The whorls are ventricose, nearly as long as broad, some-
what angular where the slit band is projecting. This band is narrow, placed a little
below the median line of the body whorl and quite on the middle line of the other
whorls. It has an even surface, fig. 24 section, the crescents are regular, fig. 23.
But near the aperture in large specimens the transverse ornamental stria above and
beneath are confluent with the band without any separating or bordering lines and
it continues only as an elevated ridge, sometimes not clearly distinct from the
surface. In this feature it shows relations to such genera as Euomphalus and
Loxonema (for inst. pl. XV fig. 9) and also to Pleurot. planorbis His. The shallow
suture crosses the longitudinal axis in a line more oblique than in the other species.
There is no umbilicus and the aperture is oblong, the uppermost corner acumi-
nated, its columellar lip thin, reflexed. Height 51 millim., width of body whorl
18 millim.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. LSE

The original specimen of Histvcer is from Ostergarn from where lately more
specimens have been obtained, and quite similar ones are very common in the lowest
shale near Wisby. It has also been found in the limestone of Gothemshammar, in
the shale beds and limestone of Slite, on Furillen, in Follingbo and in the limestone
at Kalens Qvarn.

8. Murchisonia paradoxa n.
Pl. XXI fig. 1—3.

Shell cylindrical, turreted, slowly increasing in width, whorls seven in the best
preserved of two fragmentary specimens. The slit band is situated a little above the
median line of the whorls, if is elevated, with a flat surface, crescents regular, dense,
placed obliquely on the band which is crossing the axis of the shell in a highly acute
angle. The whorls which are of equal breadth and height, are of an only slightly
convex outline, though a little more bulging out in one of the specimens. They are
adorned with minute transverse lines of the same pattern as in M. attenuata and
M. cingulata. The uppermost margin of the whorls is at first constricted by a
shallow groove, then widened in a stringlike rib, which covers the basis of the over-
lying whorls. The state of preservation of the specimens prohibits to ascertain the
shape of the aperture and the umbilicus. Height of most complete specimen 36 mm.,
br. 10 mm.

Rate of growth of the whorls:

H. Br.
1 “10mm: 10 mm.
2 8 » 9 »
3 7 » 8 »
4 Hh tl»
5 Ht yD 6 »
6 ibe 5) 5 »

Two specimens have been obtained from the gray limestone of Lindeklint.

Divisio Il. ORNATA.

9. Murchisonia crispa n.
Pl. XII fig. 13—14.

Shell turriculate, obese, thick, with six ventricose whorls which at their lowest
edge near the suture are constricted, forming a narrow vertical belt. The slit band is
placed much beneath the middle line of the whorls, a little above the suture. It is not
distinctly separated from the other surface through bordering lines and the cre-
scents are in direct continuation with the transversal lines. These are distantiated,
lamellar, imbricated. The slit is well preserved, short and tongue shaped. No um-

132 4G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

bilicus is visible and the aperture is ovate. Height 21 millim., breadth 12 millim.
Apical angle 38 °.

It has been found in the coralliferous limestone of Lindeklint and Sandarfve
kulle, one specimen from each locality.

10. Murchisonia munda n.

Pl. XIII fig. 6.

Shell turriculate, terete, with eight short, ventricose whorls, twice as broad as
high. The narrow, ropelike sht band forms a prominent angle a little below the
median line of the body whorl and a little above the same line in the other whorls,
It is hemmed in by two distinct lines and its surface is prominent and convex, the
crescents are distantiated, smooth, lamellar and imbricated, quite as in that group of
the Pleurotomariw, which has been called Crisp. In this feature the four first species
of the Murchisonix ornate are similar. Above the band, and parallel with it, a small
ridge runs on the body whorl. The surface is transversally striated by gently undula-
ting, lamellar, densely placed lines, imbricated as it were. For the rest the shell is
quite smooth without any longitudinal or transverse striw. The aperture is nearly
obliquely elliptic and the columellar lip thin and reflexed, hiding the umbilicus.

Height nearly 6 millim., breadth 3 millim.

A few specimens found in the marly strata of the upper limestone of Slite.

It comes near to the preceding species as to the ornamentation, though this is
much finer in M. munda.

11. Murchisonia tortuosa n.

Pl. XIII fig. 4, 5, 13, 14.

Shell turriculate, of nine ventricose whorls, nearly twice as broad as high, an-
gulated a little below the middle of the whorls, where the chordlike slit band is
placed. This band is narrow, convex and outstanding, composed of nearly tubular and
lamellar crescents, which cover each other successively, in an imbricating way. The
lowest part of the whorls is abruptly bent in towards the suture in a face, whereby
the suture is uncommonly deep. There is a low ridge between the slit band and
the umbilicus parallel with the former. In one specimen, fig. 13 there are also two
or three low ridges on both sides of the slit band. The ornamentation consists for the
rest in transverse, sinuous, lamellar stria. On the umbilical part there is also much
variation, in some a succession of concentric ridges, cut by striae, which are sinuous,
as in fig. 14, or in others, as in fig. 5, only transverse striae and concentric ones near
the edges. H. 11 mm., br. 6 mill.

The aperture is ovate, the inner lip reflexed and hiding the umbilicus.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. wN:o 6. oo

Only two specimens have been found, one from the crinoidal limestone of Stor
Wede in Follingbo and the other variety from a limestone ridge near the church
of Burs. ©

12. Murchisonia imbricata n.
Pl. XIII fig. 7—12.

Shell turriculate, elongate and slender, fig. 7, or short and terete, fig. 8; whorls
nine, broader than high. The slit band is prominent as a sharp edge, nearly on the
middle of all whorls or a little above. It is narrow, the crescents are long, protracted
and tube shaped, slender at their origin beneath the next preceding and slowly widening
till they form an_ erect, ‘somewhat reflexed edge, fig. 11, 12. This form of the cre-
scents very much reminds of that in Pleurotomaria tubulosa, pl. IX f. 8, though the
crescents are more narrow and elongate in Murchisonia imbricata. The same sort of slit
band also distinguishes this species from the two nearly related, preceding ones. In
the two varieties, fig. 7, 8, the ornamentation of the surface is thus far dissimilar, that
it is finer in the elongated form, than in the other. There are in both transverse,
oblique strix, somewhat elevated and lamellar at their edges and thence causing an
imbricated appearance. They are crossed by a low and narrow ridge above the slit
band on the body whorl and by a more prominent, sharp ridge on all whorls near
the suture, which is very deep. On the umbilical side the striw are finer and closer.
The aperture is nearly circular and its columellar lip reflexed, though not so much as
to hide the narrow umbilicus. H. 5 millim. br. 2 mill.

This little, beautiful shell occurs plentifully in the marly seams of the upper
limestone of Lotsbacken in Slite and a few specimens have also been found in the
limestone near Kalens Qvarn and both in the red and gray limestone of Sandarfve kulle.

13. Murchisonia cancellata n.
Bi ORIEL fie. 2

Shell turriculate, with eight transverse whorls of greater breadth than height, an-
gulated on the middle, where the slit band is situated. This band is enclosed within
two longitudinal, sharply projecting lines on each side and these again have between
them a narrow concave belt, streaked with short, oblique lines. The slit band proper
is thus very narrow, concave, the crescents of so small a size as not to be distingui-
shable. The other shell surface is cancellated by transverse and longitudinal threads of
equal size, though somewhat unequally distantiated. The aperture is nearly ovate, the
umbilicus is larger than in the others. Height of the most complete specimen 8 mill.,
br. 4 mill.

Some specimens have been found in the red limestone of Sandarfve kulle. From
this locality there is also a variety with more ventricose whorls, which seems to have
been larger.

134 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND P'TEROPODA OF GOTLAND.

14. Murchisonia cochleata n.
Pl. XIII fig. 2—3.

Shell turriculate, slender and tapering with twelve or thirteen whorls, much an-
gulated and prominent along the median line. The sides of the whorls on both sides
of the slit band are rather much more concave than in any of the preceding species,
and constricted into a vertical ring near the lower suture. The slit band is promi-
nently convex, hemmed in only by the uneven edges of the surface, and covered by
very unequal, regularly curved crescents of which some prominent are mingled with
fainter. The ornamentation on both sides consists of transverse, much curved, ele-
vated sulci, remote, the interstices striped with minute stria. On some distance from
the slit band three or four elevated ridges are crossing them; the largest is placed at
highest above the band, encircling the umbilical surface. On this same surface there
are several others, low, concentric ridges, which are crossed by finer and more closer
strie. The aperture is nearly circular and the columellar lip largely reflexed, widened
in a broad lamina near its superior corner and hiding the opening of the umbilicus.
The suture is distinct and slightly impressed. H. 18 millim. br. 8 millim.

This species has been found in some 30 specimens in the red limestone of Sand-
arfve kulle and also a few from the limestone of Katthammarsvik in Ostergarn.

15. Murchisonia deflexa n.
Pl. XX fig. 16.

Shell turriculate, with nine transverse, tumid whorls, carinated through many sharp,
longitudinal keels. The whorls rapidly increase in size in the following regular proportion:

i. Br.
1 or body whorl, 4 mill. 8 mill.
2 Sits? GO >
3 hs AL
4 1,5 » 30am)

the breadth thus increasing exactly in the double ratio of the height. A longitudinal section
of the whorls gives an oval, nearly pyriform outline, broadest above and narrow below.
The slit band, the greatest peculiarity of this species, is situated a little above the
median line of the whorls. It is a narrow and excavated groove, covered with
oblique crescents. Its superior, bordering line has grown out in a vaulted lamella, which
is bent down over the band so much that it completely hides it and its surface only
can be seen where this lamella is broken. This superior lamella is thin and sharp
edged, like a claw in the section, the inferior bordering line again is short, blunt and
horizontal. As seen in the section, fig. 6, the slit continues open along half the
body whorl. The surface on both sides of the slit band is delicately and finely cancel-
lated by lines of which the transversal ones above the slit band curve backwards only

KONGL SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 135

on the very edge of the covering lamella. Those below the band form a large curve,
directed forwards with its greatest convexity and with its upper end at the slit band bent
backwards. The transverse lines are nearly thrice as large as the longitudinal ones
and, where they meet, a thick, blunt nodule is formed. Above the slit band there are
two longitudinal keels and one smaller around the umbilicus. Close below the slit band
a sharp longitudinal keel is running and the lowest edge of the whorl is widened into a
narrow ridge, which covers the much impressed suture. A great peculiarity, which has not
been observed in any other species of the Murchisoniz, nor in any other gastropodan shell
of the Silurian formation, consists in two interior, longitudinal keels, of which one
narrow and thin, follows the inner wall of the outer side of the shell from the lower
corner of the outer apertural lip, where it is placed a little below the lowest keel.
It continues on the same level through the whole shell, as may be seen in the longi-
tudinal section, given in fig. 6. On the nucleus this ridge has of course occasioned
an impression as a narrow groove, fig 4. The other keel runs higher up near the top
of the whorls on their umbilical side and corresponds with the narrow ridge, which is
visible around the umbilicus. These may in some way be regarded as formations ho-
mologous with the continuous ridges which interiorly cover the walls of the Nerinwe.

The aperture is large, obovate, its outer lip is thin, the inner is lamellar, reflexed
and at broadest in its superior corner. The umbilicus is narrow, where it opens, and
continues downwards as a hollow axis.

The shell has in many specimens, especially on the interior side, an intense ochra-
ceous yellow colour, but whether this is due to later mineral agencies or to its retain-
ing anything of the original colouring is uncertain. H. 12 mill., br. 8 mill. Height
of aperture 4 mill., br. 4 mill.

In all, nine specimens have been found of this curious shell in the gray lime-
stone of Linde klint, on its northernmost side, and also a few specimens on Sandarfve
kulle in the gray and red limestone.

Fam. VII. EUOMPHALIDZ De Kontnck.

Shell discoid or turriculate, on the apical side or on the middle of the body whorl
provided with a shallow notch in the outer lip, in continuation of which there runs on the
surface of the whorls a slender, elevated ridge, on which the transverse strie are forming
a small angle, directed backwards without any resemblance with a true slit band. The apex
of the shell is commonly filled with solid caleareous matter of an organic deposit or even
divided in various compartments through transverse, tmperforated diaphragmata.

In adopting the name given by Dr Kontnox') to this family it is in a much more
restricted sense than he intended and such genera as Straparolus, Straparollina, Maclurea
and Rhaphistoma are according to the definition given above not to be included. The
shells of this family, of which only the genera Euomphalus, sensu strictior?, and Loxonema

1) Faune du Caleaire Carbonif. de la Belgique, II, 1m p. 107.

136 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

are Silurian, have a slit in the lower edge of the exterior lip, much more shallow than
that of the Pleurotomaride and nearly alike that in Pleurotoma and also in Turritella’).
During the growth this slit is never changed into a real slit band as in the Pleuroto-
maridxe, at the highest there is a narrow ridge, where the lines of growth are curved
backwards. When we see how mollusca, in other respects dissimilar, are provided with
this slit in their shell, it is indeed very questionable whether the Loxonemata only on
that ground are so nearly related to the genus Euomphalus as to be included in the
same family as here proposed. There may, however, be added the similarity in the
consolidated apex, and they may thus, at least provisionally, be regarded as related
and Loxonema in a certain way to hold the same position to Euomphalus as Murchi-
sonia holds to Pleurotomaria.

Gen. EUOMPHALUS Sowersy p. p.

1814 Huomphalus Sow. p. p- Mineral Conch. I, 97.

1833 Bifrontia-Drsuayes p. p. Deser. Coqu. foss. des environs de Paris, 221.
1835 Schizostoma Bronn Lethawa Geogn. Hd. 1, 95.

1843 Eecyliomphalus Portiock p. p. Report Geol. of Londonderry, 411.

Shell discoid with contiguous or disjointed whorls; on the apical side of the aperture
a shallow and obtuse slit or sinus is sttuated, the traces of which are seen on the whorls
as a more or less elevated ridge, towards which the lines of growth are turning their api-
cal angle. The apex of the shell is filled with a solid calcareous deposition of organic
origin und is often subdivided through transverse diaphragms.

After the detailed expositions of the aflinities of this genus as given by De Ko-
NINCK in his latest grand work and by SroniczKa*), Waacen®) and Ernermcr gr‘) only
a few remarks need be added, chiefly to show the standing point in this question of
J. Sowrrsy and Drsnayes, the conchologists who have most essentially influenced the
opinion of others.

When James Sowersy in February 1814 published his new genus Euomphalus
in 4 IX of the Mineral Conchology p. 97, he founded it on such species as Euomph.
pentangulatus, catillus and nodosus, all provided with the small notch in the corner of
the aperture on the apical side and a ridge in connection with it on the surface of the
whorls. But already in April the same year he joined with them in that very genus
others as E. discors, rugosus etc., which do not share in the peculiarity of conforma-
tion, distinctive of the former. Consequently, when we are to fix the characters of
Euomphalus it must be in the original conception of its author. Next, the opinions of
Drsnayes are of great importance, as most of the subsequent authors seem to have fol-
lowed him. In 1830°) he did not accept Euomphalus as an independent genus, but

1) Booger Watson Mollusea of the Challenger Exp. in Journ. Linn. Soe., Zoology, vol. 15, p. 220.
*) Paleeontologia Indica V, p. 247.

3) Pal. Ind. XIII p. 86.

4) Ann. mag. N. H. 5th Ser. vol. 5, p. 480.

5) Encycl. Method., Hist. Nat. d. Vers, vol. II p. 162.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND (9. N:0 6. 137

creates a section of it in Solarium, comprising all the three, first original species of
Sowersy. The later species, viz. E. discors, rugosus and funatus he says belong to
Turbo, and others again to Delphinula. He then quite rightly distinguished the true
Euomphali from the others and in all probability assigned to the E. discors etc. their
true place.

In the same work he in 1832’) identifies Straparolus of Monrrort with Euom-
phalus or Solarium. As the confusion in this respect has originated with him and as
most of the later authors have participated his views, it may be as well, here at once
to try to clear up this matter. Monrrorr established, as is well known, his genus Stra-
parolus*) in 1810, taking Str. Dionysii as the typical species. On comparing speci-
mens of this shell with specimens of E. pentangulatus or E. catillus it must, however,
be evident that they cannot possibly be regarded as of the same genus. In Straparo-
lus the shell has rounded, tubular whorls without the least trace of ridges, only with
some faint, longitudinal stripes and the transverse striw are not angular, as in Euom-
phalus, in Euomphalus again the whorls are angular and provided with the distinctive
ridge on the apical side. It is, moreover, highly questionable whether Straparolus is
identical with those Silurian shells which formerly were confounded with Euomphalus,
as E. discors etc. These have in the present memoir, in consequence of the nacreous
structure of the shell and the characteristic opercula been placed amongst the Turbi-
nide and in the genus Oriostoma. No opercula have ever been found belonging either
to Euomphalus sensu strict. or to Straparolus nor are they nacreous. If it steadily is
kept in view that Straparolus not at all is identical with Euomphalus s. str. and scar-
cely with Oriostoma, a great deal of difficulties will be overcome.

A change is made in 1833°) by Desnayes thus far that he creates a new genus
Bifrontia and in this he ranges E. catillus, while the other two species are left with
Solarium as before. It cannot be denied, that there is a certain resemblance between
such shells as the Gotlandic E. tuba and Dersuaynrs’ Bifrontia ammonoides and B.
Deshayesii*) and likewise amongst recent shells, Omalaxis (Bifrontia) supranitida Woop
has a shape that reminds of that of the palaozoic.

In his last great work*®) he maintains Euomphalus as a genus distinct from So-
larium, though belonging to the same family. He is further (1. c. p. 678) willing to
accept Bronny’s Schizostoma for E. catillus. As to the last mentioned genus, established
with E. catillus as type, it was rejected by Frrp. Roemer"), who regards the indented
curvature of the aperture too insignificant as a generic character. It may, however,
be questioned whether this genus ought not to be retained for such Devonian species

1) Vol. IIL p. 986.

*) Conchyliologie System. II, 174.

3) Description des Coquilles foss. des Environs de Paris IT p. 221. This work is dated 1824 on the title
page, but it was published in small parts and it lasted till 1839 before it was completed. According
to Hermannsen Indic. Generum, Bifrontia was published in 1833.

4) Anim. sans vertébres dans le Bassin de Paris, II pl. 26 f. 22—28.

°) Anim. sans vertébr. dans le basin de Paris. Vol. Il, 660.

5) Leth. Geogn. 3:e Aufl. 1 Bd, 456.

>
K. Sy. Vet.-Akad. Handl. Bd. 19. N:o 6. 18

138 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

as Schizostoma Pusozii and Sch. radiatum, which are of a type entirely different from
K. catillus.

To sum up the chief results now gained, I believe:

l:o) that Euomphalus is to be maintained in the sense which Sowersy at first
gave it.

2:0) that Straparolus, as well as Oriostoma must be removed from Euomphalus
as not identical with it and belonging to different families, Oriostoma being one of
the Turbinide.

3:0) that of the Silurian shells Euomphalus along with Loxonema must be re-
garded as members of the family of the Euomphalide Dr Kon. p. p. and

4:0) that this is to have its systematic place next to the Pleurotomaride, as there
are forms linking both together.

Eecyliomphalus, the only remaining synonymic genus, the identity of which
with Phanerotinus is doubtful, comprised, when first established, two species and the
author, Porriock, lays stress on »its great resemblance to an unrolled Euomphalus».
And, in fact, these species come near to such as our E. Gotlandicus and E. triquetrus.
But by and by quite different shells were introduced into it. Eccyl. alatus Fern. Ror-
MER, concerning which species see above at page 110, is an instance of the adventitious
forms. This genus has thus come to contain species of evolute Euomphali and like-
wise evolute Pleurotomarix. It must, consequently, be broken up, and its species be
distributed in these genera. both the typical species are Euomphali.

The genus Euomphalus has a wide geological range. In Sweden the oldest spe-
cimens have been found as deep down in the Lower Silurian as in the Lower Gray
Orthoceratite limestone of Dalecarlia, from where the specimen, delineated on pl. XIII
fig. 36—38 has been derived. It is evolute, with three widely separated whorls of cir-
cular section, the aperture angulated in its lowest corner, where the large and distinct
slit, fig. 36, is situated. The ridge in continuation of this runs very sharp along the
whole apical side of the whorls. The ornamentation consists of imbricated, transverse
strie, curved back in an acute angle, where they cross the apical ridge. The oldest
whorls on the visible part of the apex is divided in chambers through at least four
transverse diaphragmata. I have named this interesting species Huomphalus Angelini
in remembrance of the indefatigable and gifted man, Professor N. P. AncELin who devo-
ted his life to the investigation and elucidation of the paleontology of Scandinavia.

Next in order of time we find a Euomph. obtusangulus’) which resembles the
Upper Silurian E. Walmstedti and E. precursor, in the Leptena limestone of Dalecar-
lia. In the Upper Silurian of Gotland there are five species, besides fragments indica-
ting others. It is well known that there have been several species found both in the
Devonian and Carboniferous formations expecially in the later, where the genus seems
to have attained its culmen. Whether the Euomphali had continued during the Meso-
zoic times is uncertain. They have, it is true, been recorded as occurring in the Tri-
assic Rocks of Austria”). But the form of these presumed Euomphali does, certainly

1) AnceLiIn & LinpstromM. Fragmenta Silurica p. 12 pl. XVII f. 19—20.
2) See the works of KiipstEin and Lavse.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. 139

not harmonize with that of the paleozoic Euomphali. As SroniczKa has shown’),
most of the Jurassic forms belong to the genus Discohelix, of which there probably
already is a representative in the Devonian strata of Nassau”). It is possible that this
genus has continued during the Tertiary times and still survives in the Mediterranean
and Atlantic seas.

As to the species here described in this genus, E. tuba n. may be only provisio-
nally included in it, as it deviates somewhat in its form and possibly rather is an
Oriostoma. On the other hand, it must by future researches be decided whether Orio-
stoma angulatum WAHLENBEBG rather not is an Euomphalus.

1. EKuomphalus Gotlandicus n.
Pl. XIII fig. 19—31.

Shell disciform, involute or disjointed, at the highest with five whorls. These
are cylindrical and nearly triangular in section, the slit and its concomitant ridge being
on the apical side. The oldest mutation or variety, which occurs in the shale beds,
has only the nucleus left and is generally involute (figs. 19—22) with a wide and open
umbilicus showing all whorls. The aperture is in the best specimens triangular, the
ridge forming an angle, the outer lip thin, a little reflexed outwards. The tendency to
disjoint can be traced in specimens where the whorls are coiled in, but have some free
space between them, to those where they are quite uncoiled as in figs. 23—25. From
the same geological horizon the specimens figured in figs 30—31 have also been ob-
tained. In the uppermost limestone strata near Wisby hitherto only uncoiled speci-
mens have been found as shown in figures 26—29. In them the aperture is more
triangular than in the involute forms from Wisby a. The ornamentation of the sur-
face is nearly alike in all, consisting of thin, transverse threads bent in an angular
line curved backwards from the apertural slit. This slit is situated nearly in the
middle of the lower edge of the aperture and forms a highly obtuse angle. The three
oldest whorls are filled with solid calcareous deposit, figs. 22, 29, and the uppermost
surface of this stratum is deeply concave.

H. 20 mill., br. 42 mill. of involute specimen.

H. 15 mill., br. 39 mill. of uncoiled specimen.

The involute variety is found in great numbers in the lowest shale near Wisby,
and also at Westergarn and Stormyr in Rute. The uncoiled variety is found in the
same localities and moreover in the uppermost limestone beds of Kyrkberget in Wisby
and at Kalens Qvarn, Hogran, the shore of Slite, Weskinde.

From the shale of Wisby some nuclei have been obtained in all particulars re-
sembling the common involute one, excepting in having some slight longitudinal ridges
along the apical side. They are, however, not in a sufficiently good state of preserva-
tion for description and delineation.

') Gastropoden der Hierlatz Schichten. Sitzungsberichten der Ak. Wiss. Wien, Bd 43, 1, p. 180,
*) Euomphalus rota Sanps. Nassau p. 212, pl. 25 f. 5,

140 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

2. EKuomphalus triquetrus nv.
Pl. XII, fig. 32—35.

Shell discoid, of triangular section, with four whorls, of which the older are
contiguous and the body whorl free through almost its whole length, rapidly widening,
much more so than in E. Gotlandicus and it is broadly expanded at the aperture.
The three smaller whorls, which form the apex, are filled with a homogenous, cal-
careous deposit, only interrupted by a transverse diaphragma in the second whorl.
On the interior side of the umbilical surface the nucleus of the body whorl has a
shallow, longitudinal groove, being the impression of some internal ridge. The um-
bilical side is the Jargest, nearly flat, and the two other shorter sides meet in an obtuse
angle on the apical side. The aperture is transversally triangular, broader than high,
the inferior corner acuminated. It is oblique and the superior lip more prominent
than the inferior one. The notch in the inferior lip is broadly triangular, fig. 35,
and deeper than in the preceding species. H. of aperture 16 mm., br. 22 mm., dia-
meter of the shell 51 mm.

Specimens have been obtained from the shale and limestone of Slite, from Boge,
Westkinde and Hogran.

3. Euomphalus tuba un.
Pl. XVIII fig. 6—8.

Shell globular, with a low, though prominent spire and four tubular whorls.
They are ventricose, with slightly elevated ridge in continuation of the apertural in-
dentation. The suture is deep and the whorls sink much abruptly towards it. The
ornamentation consists in narrow longitudinal threads, which are crossed by indistinct,
transverse lines of growth, coarser and finer, forming an obtuse angle in the same
line as the slit is situated. The aperture is circular and the lips thin, the umbilicus
is narrow, but open.

H. 7 millim., br. 10 m.

A single specimen from the limestone of Samsugn in Othem. A nucleus from
Martebo of larger dimensions may possibly also belong to this species.

4. Euomphalus preecursor n.
Pl. XVIII, fig. 9—11.

Shell discoid, spire moderately prominent, of five whorls, rapidly increasing in
size, the body whorl in breadth surpassing all the others. The narrow characteristic
keel is seen a little below its median line, having inside it towards the suture a flat
surface. On the umbilical side of the body whorl there is a narrow, sharp keel nearer

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19, N:0 6. 141

to the umbilicus than the exterior margin, on the inside of which a scooped out belt
is formed, being bordered by a sharp edge where the umbilicus begins. The striation
on the surface is only transversal, slightly bent in a sinus where it crosses the keel.
The strix are narrow, elevated and thread like. The aperture is transversally ovate,
the umbilicus rather narrow. H. 6 mm., br. 17 mm., diameter of umbilicus 5 mm.
Another specimen: H. 5 mm., br. 11 mm., umbilicus 3 mm. ‘Two specimens from the
shale of Wisby. From Dalhemsa, near Nya Slitegards, the museum possesses a single
specimen, which perhaps is only a variety of this species. It is, however, different in
not having the inferior keel so prominent and the whorls are convex, not flat between
the keel and the suture. Oi the umbilical side it is more conformed to the former.

The shape and sculpture of E. pracursor remind of the far larger species from
younger paleozoic formations.

5. Euomphalus Walmstedti n.
Pl. XVIII fig. 12—14.

Shell discoid, spire on a level with the body whorl, whorls seven. On the
apical side a blunt ridge is running longitudinally and the surface of the whorl inside
it and the suture is sloping towards the suture or even a little scooped out. The
median line of the whorl, on the dividing line of the apical and umbilical side, is
obtusely carinated. A little inside the longitudinal axis of the umbilical side there is
a sharp, narrow keel, from which the side slopes gently inward. A narrow, sharply
defined groove marks the suture on the umbilical side. The transverse striation, the
only one extant, is extremely fine and the striw are slightly angulated when crossing
the inferior ridge. The aperture is transversally ovate, angulated, the umbilicus wide
and open. H. 4 mm., br. 13 mm., umbilicus 4 mm. Several specimens have been
obtained from the red limestone of Sandarfve kulle. There are also specimens from
Samsugn in Othem and Klinteberg, which probably are only varieties of this species.
They have the whorls more rounded and the keels blunt or nearly evanescent. The
wider umbilicus and the conformation of the whorls around it, as well as the quite
different striation, distinguish this species from the former.

Gen. LOXONEMA Puitrrs.

1841 Lowonema Pury. Paleozoic Foss. Cornwall, p. 98.

Shell turriculate, with long, slender spire of ventricose whorls; u shallow indenture
occurs in the exterior lip of the aperture. The lines of growth and also the ornamental
ones are bent in an obtuse angle, the apex of which is situated in a line with the aper-
tural indentation. The aais is solid and the oldest whorls are jilled with an organic
deposit of homogenous calcite as in the preceding genus.

142 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Of the species first included within this genus almost all have the characteristic
features of »the oblique prominent thread like stria which cover the surface in all the
typical species» and as also the etymology of the name implies. In spite of such
expressly given characteristics by the first author later naturalists have placed within
the limits of this genus shells which are ornamented in a quite different manner, and
rather should be regarded as belonging to other genera. Only such shells, in which
the ornamental strie form an angle along the median line of the whorls or near that
line conformably to the first typical species, should be placed here.

Michelia of Ap. Ferp. Rormer') comprises shells with nearly the same ornamenta-
tion as in Loxonema, but with whorls and spire more like those in Trochus or Terebra.

Species of Loxonema have been found in the Silurian and Devonian formations.

A few have also been found in the Carboniferous limestone, though a great many
have been introduced in this genus without showing the distinctive characteristics.
But of all those described as Loxonema by Lause*) from the Triassic strata of St.
Cassian not a single one can be regarded as appertaining to that genus.

In the Silurian of Gotland five species have been found, differing from each
other in the shape and relative size of the whorls as well as in the position of the
insinuation and the character of the angular strix.

1. Loxonema sinuosum Sowerrsy.
Pl. XV fig. 1—5, 7.

Terebra? sinuosa 1839. Sowerby in Sil. Syst. 619 tab. 8, fig. 15 (not Saurer in Mem. Geol. Survey
II, 1, 357, pl. 14 f. 2, which is = Murch. cingulata H1s., Loxonema

sinuosa Puitiies Pal. Foss. Cornwall 99 pl. 38 f. 182 is a Devonian
species distinct from the Silurian and has to be renamed as it is of later date).
Loxonema sinuosum 1848. Bronn Nomenclator, 670.
1850. D'Orspieny Prodrome I, 29.
1854. Morris Catal. Brit. Foss. Ed. 2, 255.
1859. Sater Siluria 3 Ed., 549 tab. 24 f. 3.
1873. Ip. Catal. Cambr. Foss., 172.
Holopella (obsolete Sow. aff.) 1867. Linpstrém Nomina, 23.

Shell elongate, turriculate, with eight whorls, which are transverse, broader than
high, ventricose, constricted in a narrow belt close at the suture and the lowest edge
of the whorl hiding and covering the suture. Suture crossing the axis of the shell
in a very acute angle. The surface is covered by very fine, elevated lines, which are
bent in a nearly rectangular curve, along a line somewhat below the transverse median
axis of the whorl corresponding with the position of the obtuse indentation of the
aperture. The stria are finest on the body whorl, being more and more coarse and
changed into elevated, angular ridges on the older whorls. The aperture is ovate,
the columellar lip having besides it only a narrow, umbilical fissure open, which is

') Paleontographica Bd. 3, p. 73.
*) Denkschriften der Ak. d. Wiss. zu Wien 1868 Zweite Abth., p- 60,

KONGL. SV. VE'’. AKADEMIENS HANDL. BAND. 19. N:o 6. 143

completely closed in the interior, the columella being solid, fig. 4. The apex is a homo-
genous mass of calcareous spar, fig. 4, and consequently the nuclei, fig. 5, are ending
in an obtuse truncation. H. 24 millim., width of body whorl 12 millim.

Size of the whorls in two specimens.

Spec. A. Spec. B.
Whorls. H. Br. Whorls. H. Br.
1 8 mm. 12 mm. 1 Semin.) Zeman:
2 Bi oath 9” >» 2 On > Shh
3 5 . Go) 3 An) 7 »
4 3} » 5 » 4 3) » 5 »

Very common in the shale at Djupvik in Eksta and also in few specimens

from Wisby.

2. Loxonema attenuatum n.

Pl. XVIII fig. 3—5.

Shell elongated, turriculate, of 8-9 whorls, nearly as high as broad and in some
specimens exactly so, moderately ventricose or even approaching to a cylindrical shape
with straight sides, a little constricted around the inferior edge and slightly covering
the shallow suture. The apex of the angular and very fine strix is situated a little
higher than those of the preceding species or near the median line. The corrosion of
the surface has caused a false appearance as of a slit band. The aperture is longer
than broad, oval, the interior lip broad and reflexed; no umbilicus is visible. Length
of a fragment 27 millim., breadth of body whorl 9 mill, probable length of complete
specimen 35 mill. Dimensions of whorls in four specimens:

A, whorls. H. Br. B, whorls. H. Br. C, whorls. H. Br. D, whorls. H. Br.
1 10mm. 11 mm. 1 8mm. 10mm. 1 9mm. 9mm. 1 wanting.
Dy ~ kay 8 » 2 iG?) 8 » Py tS) (op) 2 @mm. 8mm.
3 yD) 6 » Si Aue) — Sai) 5» By 6 »
AL By oy — 4 4 » 4 »
ay oD SD

Nine specimens have been found in the limestone of Samsugn in Othem.
A fragment of a large Loxonema from Follingbo somewhat reminds of this spe-
cies but cannot be defined with certainty.

3. Loxonema intumescens pn.
Pl. XV fig. 6.

Shell turriculate, with a slowly tapering spire, of which six whorls are left.
These are ventricose, larger than high in the following ratio.

144 4a. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Whorls. H. Br.
Lh sk ieee hoe ae 10 14
2. ee tbe a ff 11
3, See 5 8
4 ovale bide i 4 6
D, eiciieuee ke ee 3 5
Oath ne | «A ete 2 4

The increase is consequently more rapid in the youngest whorls. The suture is
moderately deep and the whorls are regularly rounded down to it, without any con-
striction. The apices of the angular strix are placed on the middle of the whorls
and resemble those of Lox. sinuosum. H. 32 millim., br. 14 mm.

Only one specimen has been found in the upper limestone near Wisby and there
are also some from Westergarn.

4. Loxonema strangulatum np.
Pl. XV fig. 8—10.

Shell turriculate, long and slender, of at least six whorls. As may be seen by the
dimensions, given below, the whorls are of nearly double the height against the width.
They are only moderately ventricose, as to appear almost cylindrical, the suture is
oblique, more so than in the other Gotland species. The lowest part of the whorls
is constricted in a rather broad belt just above the suture. The ornamentation con-
sists of the usual striw, bent backwards on the middle of the whorls in a sharp rect-
angular sinus.

Height of longest specimen from QOstergarn 47 millim., br. 8 mill. Height of
second whorl in the Klintebere specimen figured 8 millim., breadth 5 millim.

‘Found in the limestone of Ostergarn and Klinteberg.

5. Loxonema? fasciatum n.
Pl. XV fig. 11, pl. XX fig. 7.

Shell slender, elongate, turriculate, with about 16 slightly convex whorls, glossy,
though covered with exceedingly minute transverse striw, which are curved backwards
in an angle. The apex of this angle is obliquely arched and taken together the apices
of all striw form, exactly above the median line of the whorl near the upper suture,
a relatively large band, somewhat resembling the slit band in Murchisonia, as for in-
stance M. crispa. It is however not clearly defined from the ambient surface, through
bordering lines and the species may, untill further information is gained, be left with
Loxonema. The whorls are a little longer than broad. The aperture is ovate. H. 13
millim., br. 2 mm.

A few specimens have been found in the red limestone of Sandarfve kulle.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. 145

Fam. VIII. TROCHIDZ D’Ors.
Gen. TROCHUS L.

1758 Trochus L. Syst. Nat. ed. X, 756.

1879 Paleotrochus J. Hau Pal. N. York vol. V pt. Il, 133.

1881 Flemingia De Konixcx Faune II, m1, 94.

1882 Fotrochus WuirrreLp Bullet. N:o 3 of American Museum of Natural History p. 77.

It is with great diffidence the following species have been described as belonging
to the old genus Trochus. The only reason for placing them there is the general
exterior shape of the shell, it having not been possible to find any evidences from the
microscopic structure of the shell nor from any traces of a nacreous stratum or an
operculum. On the other hand, there are so many genera of shells which have per-
sisted from the Silurian age through all the following and still continue, and it may
therefore not be thought an impossibility that also the Trochi existed already in the
Silurian times. Moreover, it is generally adopted that species of Trochus have been
found in the Devonian rocks, where they, however, as well as in the Carboniferous
limestones, not are numerous. Most of these paleozoic Trochi are nearest allied to
that division, where the inner lip is thin or only slightly thickened, and the umbilical
side flat. A few, as Tr. profundus and Tr. cavus ‘) evidently belong to a section of
Paleozoic Trochi, out of which Wurrrietp (1. c.) has established his genus Eotrochus.
They have exactly the same cup shaped conformation of the umbilical side, which has
led some authors *) to place similar ones from the Jurassic formations with the Phoridx
in the genus Onustus. I think, however, that the Paleozoic may, at least for the
present, be retained in Trochus. On comparing the beautiful figures of Tr. lamellosus
for instance in D’Orpicny’s Pal. Francaise, Terr. Jurass. pl. 311 fig. 11—13, the re-
markable similarity with the Silurian Tr. cavus and profundus is evident. There is in
all the same cup shaped umbilical surface, the thin, lamellar border around it and the
open umbilicus. There are no traces of any nacreous stratum. The columella, probably
solid in some, is in many replaced by a wide, open, funnel shaped axis. The apex of
the whorls is filled up with a calcareous deposit.

Sixteen species have been discovered in the limestone beds of Gotland, none
having hitherto been found in the subjacent shales. These species may be divided
into the following groups.

I. TRANSVERSI, transversally ornamented by oblique lines.
1. Tr. Gotlandicus n.
2. Tr. fulminatus n.
3. Tr. mollis n.
1) Probably also Tr. Stuxbergi and undulans.
*) Hupreston Contributions to the Pal. of the Yorkshire Oolites. Geol. Mag. 1884, p. 293.

K. Sv..Vet. Akad. Handl. Bd. 19 Nio 6. 19

146 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

4. Tr. Stuxbergi n.
5. Tr. undulans n.
6. Tr. profundus n.
7. Tr. cavus n.

8. Tr. Lundgreni n.
9. Tr. Kolmodini n.

II. GARINATI with longitudinal keels.
KO: Tr: Dabli,n,

11. Tr. Wisbyensis n.

12. Tr. lamellosus n.

III. INCISI with angulately impressed suture.
13. Tr. incisus n.

14. Tr. gyrans n.

15. Tr. densestriatus n.

IV. SPINOSI with spiny processes along the suture.

16. Tr. astraliiformis n.

No species has as yet been found in the Lower Silurian beds of Sweden.

Div. I. TRANSVERSI.

1. Trochus Gotlandicus n.
Pl. XIV fig. 1—11.

Shell broadly conical, sides even, only slightly convex, whorls seven, transversally
striated by the oblique, backwards directed, lamellar, wavy lines of growth, which over-
lap each other and consequently give the surface an imbricated appearance. They vary
finer (fig. 1) or coarser (fig. 6). Where the umbilical and apical faces of the last whorl
meet they form an acute angle which often is prolonged into a horizontal, solid keel.
The umbilical surface is nearly flat, smooth, striated by minute, dense lines. The
aperture is oblique, almost triangular. The outer lip is thin and sharp, the inner lip
reflexed. The umbilicus is closed and there is a marked circular depression around
it, defined by a narrow, thread like ridge. The columella is solid. The suture is shallow,
often covered by the lamellar keel of the preceding whorls, and the outlines of the
different whorls run in a continued profil without any interruption. The apex of the
shell is filled up with solid calcareous matter. A peculiar reticulated structure is shown,
fiz. 9, in thin, transparent cuts of the shell.

H. 18 mill., br. 35 millim.

It occurs plentifully at Lansa and Lutterhorn on Firé, in the limestone of Slite,
Hall near Westéés, in the coast all along the shore from Likkershamn to Wisby. A single
nucleus has been found in the shale near Wisby and probably belongs to this species.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 147

2. Trochus fulminatus np.
Pl. XIV fig. 12—13.

Shell small, broadly conical with five ventricose whorls and deep suture. The
ornamentation is peculiar and characteristic. The distantiated, transverse lines are a
little below the middle of the whorls suddenly bent in an obtuse angle, thus forming,
as it were, a lower field of stria on the belt next above the suture. The aperture is
transversally obovate, the lips thin, the umbilicus closed and the central part of the
umbilical face deeply depressed and surrounded by a low ridge. H. 10 willim.,
br. 10 mm.

A few specimens of this characteristic little shell have been found in a white
crystalline limestone north of Wisby, along the shore of Westkinde and Lummelund.

3. Trochus mollis pn.
Pl. XIV fig. 14—17.

Shell large, broadly conical, of six tumid whorls, which are only obtusely cari-
nated between the apical and the umbilical surfaces. The sculpture differs totally
from that of the preceding ones and consists only in microscopically minute, transverse
stria, very regularly distantiated from each other. The aperture is obliquely elliptical,
the outer lip thin and sharp, the interior lip strongly reflexed or thickened. The
umbilicus is almost hidden through it and is only discerned as a narrow slit.

H. 21 millim., br. 27 millim.

Some specimens have been found in the limestone of Klinteberg and Samsugn,
and also in Lilla Carlsd, from where the Mineralogical Museum of Copenhagen has
obtained a specimen.

4. Trochus Stuxbergi n.
Pl. XIV fig. 59—69.

Shell small, obtusely conical of five or six whorls, which are ventricose, most
tumid near their inferior edge and the sides above nearly vertical. The ornamentation
consists of sigmoid, obliquely transverse, laminar striw. The umbilical and the apical
sides are separated through a horizontal ridge, the extreme, thin margins of which are
much broken and jagged and are left behind in their old place on the older whorls,
having coalesced with the shell. The thin edges of this ridge form an upwards direc-
ted rim around the umbilical surface giving it a saucer-shaped appearance, elevated in
the centre around the narrow, but completely open umbilicus. The aperture is circular
or obovate, fig. 59. The outer lip is, when entire, thin, but thickens towards its upper-
most corner, where the horizontal ridge is situated. H. 11 mill., br. 13 mm. Another
specimen h. 7 mill., br. 9 mill.

148 «a. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Several specimens have been obtained from Klinteberg and Samsugn, and also
from Kyrkberget in Wisby.

It reminds, as to the ornamentation, of Trochus Gotlandicus, but the transverse
strie are more straight in that species and sigmoid in Tr. Stuxbergi, moreover the
umbilical side and the shape of the whorls is quite different in both.

5. Trochus undulans pn.
Pl. XVI fig. 8—10.

Shell small, obtusely conical of five tumid whorls, bulging out near their inferior
part and with the sides above straight and vertical, whence the body whorl acquires
a cup shaped appearance or also they are of a concave outline, fig. 8. The oblique,
transverse lamelle of growth are distantiated, and have their projecting edges much
wavy and folded in a great number of sinuosities, quite peculiar to this species. The
umbilical side is nearly flat, in the centre excavated into a deep funnel, on the bottom
of which the opening of the narrow umbilicus is seen. The horizontal ridge which
all around borders this surface is thin and wavy. The aperture is circular, enclosed
within thick lips, the outer one being especially large and in its uppermost corner
angulated.

H. 8 mill., br. 12 mill.

Only three specimens have been found, two from the upper limestone beds of
Slite and the third from Samsugn in Othem.

6. Trochus profundus n.
Pl. XVI fig. 11—13.

Shell of moderate size, broadly conical with large periphery of the umbilical side
and short spire. Six whorls of somewhat concave contour. The ornamentation con-
sists of oblique, transverse striz or rather steplike gradations following each other at
wider distances than the strie in the preceding species. When seen in a section,
cutting them transversally they have a serrated appearance. The umbilical side is quite
smooth and glossy, excavated or cup-shaped, through the large, very thin, upwards
directed borders, which encircle the upper side of the whorls and the aperture. This

is circular and lies at some distance inside the border of the shell. A

Qe shallow, curved groove in direct continuation with the aperture, indicates

the place the animal occupied when protruding itself from the shell.

“TE Sena SORRL The outer lip is thin and sharp, the interior one thicker and straight.

dus, natural size. The umbilicus is open and wide; the axis is open as seen in the annexed
woodeut. H. 13 mm., br. 16 mm.

Two specimens have been found in the limestone of Samsugn in Othem. In
this, as well as in the following species and Tr. Stuxbergi and Tr. undulans, the

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 149

formation of the umbilical side in some way reminds of the appearance of the same
side in Trochita and Galerus, but perhaps more so of that in Onustus or Phorus
(f. inst. Ph. exutus). Their great. accordance with such Jurassic forms as Trochus
lamellosus D’Orsicny is also already above indicated. There is also a Lower Silurian
genus Clisospira, first described by Bruuines in Canada, and also found in the beds of
the red Trinucleus shale of Ostergétland, nearly allied to these forms.

7. Trochus cavus n.
Pl. XVIII fig. 15—17.

Shell broadly conical, with a large periphery of the umbilical side and obtuse
apex. Whorls five or six, of faintly concave outline, transversally striated, striae gently
arched, distantiated with smooth interstices. Section of whorls transversally elliptic.
The suture is completely hidden by the superior borders of the whorls, which have
coalesced with the younger whorls and thus form an even apex. The umbilical side
is a deep, cup shaped hollow, more like that of a Phorus than that of the preceding.
The encircling borders of the shell are higher and thinner. In a shell of 17 millim. in
length there is a vertical height of 10 millim. for this umbilical hollow. Its surface
is almost smooth, only with indistinct, transverse striw. The bottom, a gently cleva-
ted belt around the umbilicus, is formed by the upper side of the body whorl, which
is more flat and expanded than in Tr. profundus. It is separated from the thin lips
of the border through a slightly elevated, narrow, annular stripe. The aperture is
ovate, lips thin and sharp, the umbilicus is open and wide. Height 9 millim, br. 20 mm.
Another specimen h. 14 mm., br. 22 mm. Fragment of a large specimen 30 mm.
in breadth.

Some specimens have been obtained in the red and gray limestone beds of the
hills of Linde and Sandarfve.

8. Trochus Lundgreni n.
Pl. XIV fig. 46—53.

Shell large, broadly conical, whorls eight, rapidly increasing, slightly convex,
superior border enlarged into a broad lamellar ridge, horizontally outstanding and
separating the umbilical surface from the apical. This ridge is visible on all whorls
and projecting beneath the shallow suture. As seen in the magnified section of this
ridge, fig. 52, its interior cavity has been divided through about five, transverse dia-
phragms. On looking at fig. 47 and the magnified corner of the aperture, it can be
questioned whether these apparent interior, transverse diaphragms are not rather to be
regarded as the sections of several such apertural edges, as seen in fig. 47, formed
inside each other, every new one smaller than its predecessors. In fig. 53, showing a
weathered edge, there are also some such apertural corners brought forward. The
ornamentation consists of narrow oblique sigmoid striz. On the slightly convex

150 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

umbilical side the striaw are still finer. The aperture is nearly circular, only widened
into a small angular wing in the superior corner. The outer lip is thin and narrow,
the inner lip strong, reflexed back towards the umbilicus and partially concealing it.
The columella is open for a little more than half its total length, solid towards the
apex. The shell which is thickest around the narrow but open axis, consists of two
distinct layers of which the interior one is dark and transparent, the exterior pale
and opaque. H. 26 mm., br. 38 mm.

It occurs at Samsugn in Othem, from where some twenty specimens have been
found and also in the limestone of Lutterhorn in Faré, where a smaller and more
conical variety occurs.

9. Trochus Kolmodini n.
Pl. XIV fig. 32—34.

Shell elongated, acuminately conical, of six whorls, with slightly concave outline.
The ornamentation consists in lines of growth regularly curved backwards and equally
distantiated, their edges clevated into a fine and sharp lamina. The interstices are
smooth. The umbilical side is flattened and finely striated. An obtuse angle is formed
between it and the apical side. The suture is acutely impressed and deep. The aper-
ture is transversally elliptical, the outer lip thin and sharp, the inner lip folded back
and hiding the umbilicus. H. 12 millim., br. 10 mill.

A single, but complete specimen has been obtained from the limestone of Stor
Wede in Follingbo.

Divisio Il. CGARINATI.

10. Trochus Dalli n.
Pl. XIV, fig. 18—21.

Shell turbinated, ventricose, with five whorls, which are minutely and densely
striated. Along the middle of the whorls there are two longitudinal ridges close to
each other, not much prominent, softly convex; the aperture is circular, outer lip thin,
inner lip reflexed along its entire length and hiding the umbilicus. The suture is
moderately deep. H. 13 wmill., br. 15 mill. Specimen, fig. 21, is of a variety with
broader whorls.

Several specimens have been found in the limestone of Kyrkberget in Wisby.

11. Trochus Wisbyensis.
Pl. XIV fig. 35—43, 45.

Shell of much variable shape, obtusely or elongately conical, with lone tapering
I yi g ’ s 8
spire, whorls six or seven, ventricose and broader than high. The ornamentation is

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:o 6. 151

also highly variable, transversally oblique lines running either uniformly as in fig. 36
and 39 or distantiated and elevated at their edges into thin lamelle. In a longitudinal
direction there are in most specimens (fig. 36, 40) two keels on both sides of the
middle of each whorl, much distant from each other. In others again, as specimen
fig. 39, there is only one ridge, the uppermost one, and in such as fig. 41, 43 there
are no less than three keels, a third placed just above the suture. A fourth is follow-
ing the outer edge of the umbilical surface, fig. 42. The aperture is transversally
oblongate, with thin lips, of which the inner one is reflexed and hides the umbilicus.
H. 23 mill., br. 19 mill.

From the limestone of Kyrkberget in Wisby, where many specimens have been
found, from Samsugn in Othem, from the limestone of Ar, and from Lutterhorn in Fard.

12. Trochus lamellosus n.
Pl. XIV fig. 44, pl. XV fig. 52—54.

This species differs from the preceding chiefly in the ornamentation. The trans-
verse lines are much distantiated and elevated at their edges to projecting lamine.
At the suture they intercross with the pointed continuations from the striz of the
next whorl. It has been found in the canal near Westéds in Hall. H. 12 mm.,
br. 10 mm.

Another extreme form of this species has been found in the limestone of Samsugn in
Othem by Professor P. T. CLEvr, the only specimen of which belongs to the Mineral
Cabinet of the University of Upsala and has been delineated on plate XV fig. 52—54.
It is elongate, turriculate of seven whorls, which taper rather rapidly towards the
apex. On the body whorl there are two longitudinal keels as in the former, having
between them an excavated zone. The uppermost keel of the lower whorls is almost
hidden, coinciding with the suture and partially covered by the lowermost border of
the following whorl. There are distantiated, transverse lines running obliquely and by
being folded in projecting thin lamine they form the keels. The aperture is obliquely
elliptical and the interior lip which is thin, nearly hides the umbilicus, of which only
a narrow slit is to be seen. The umbilical side is almost flat, covered by densely set,
transverse, thin laminae. H. 13 mill., br. 9 mill.

Divisio III. INCISI.

13. Trochus incisus n.
Pl. XIV fig. 22—31.
Shell regularly conical of six gradually increasing whorls evenly sloping, with

slight concavity or even in some specimens of convex outlines. Body whorl ven-
tricose with the umbilical side moderately convex, a narrow slightly elevated keel

152 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

encircling its middle line. This keel is situated just below the suture in the older
whorls, which are hidden as to their upper part. The surface is striated by oblique,
exquisitely fine, a little serrulated lines, directed backwards. The deeply incised suture
is most characteristic though there are variations as to its depth. For instance a shell
from Follingbo, fig. 19, same locality as fig. 26—27, has rather no incision at the
suture or one only very shallow, the inferior border of each whorl beginning further
down on the next preceding. The aperture is circular, the outer lip thin, the inner
lip reflexed. The umbilicus is narrow, but open. H. 17 mill, br. 17 mill. Length
of aperture 9 mill., width 10 mill. Several specimens have been found at Kyrkberget
in Wisby, Samsugn in Othem, Stor Wede in Follingbo; from Likkershamn there are
specimens in the Mineralogical Museum of Copenhagen.

14. Trochus gyrans n.
Pl. XVIII, fig. 18—20.

Shell regularly conical of eight tumid whorls, which are carinated along their
median line and just above the suture form a horizontal, flat surface like a narrow
band along the inferior part of the whorls, bordered upwards by a narrow ridge.
The sculpture consists in fine strix, which are somewhat more irregular than in the
preceding. The aperture is circular and the outer lip thin, the inner one thickened
and there is the appearance of a sinus where both lips meet at the lower end of the
aperture. The structure of the umbilicus is peculiar. It is a wide, funnelshaped
opening, limited partially by the inner lip and partially by a sharply defined wall,
which is encircled by a narrow ridge and is continued spirally down to the more
narrow and deeper opening. H. 19 millim., br. 15 mill.

Two specimens have been found on Kyrkberget in Wisby together with the pre-
ceding, to which it is nearly related. It differs, however, chiefly through its peculiar
and characteristic umbilicus.

15. Trochus densestriatus n.
Pl. XVIII fig. 34—23.

Shell minute, elongately conical of six whorls with slightly concave outline.
3eneath the shallow suture there is a low, elevated ring around the upper edge of the
whorls, which on the body whorl is situated exactly where the apical and the umbilical
surfaces meet. There are regular, dense, microscopically fine streaks, running nearly
vertical on the whorls, slightly arched. The aperture is rather obovate and the lips
thin and sharp, the outer one bent inwards and the inner one narrowly reflexed, no
umbilicus is visible. H. 5 millim., br. 3 mill. Four specimens have been collected in
an earthy, bituminous limestone at Hessle in Ostergarn.

It comes near to Tr. incisus, but is sufficiently well distinguished through its
peculiar striation and the angular aperture.

KONGL./SV.. VET. AKADEMIENS HANDL.* BAND. 19. N!o 6... © - 153

16. Trochus astraliiformis n.
Pl. XIV fig. 54—58.

Shell conical, tapering to a narrow apex from a broad body whorl. Eight whorls.
Their upper border lacerated, as it were, by thick, spinous projections, the base of
which completely conceals the adjoining suture. These processes are formed by reflexed
folds of the successive lines of growth, as may best be seen on the umbilical surface
of the shell. A little beneath this edge there is a longitudinal bulging out of the
whorls. Between the lines of growth the convex surface of the shell is smooth or
most finely, transversally striated. The aperture is nearly circular, apiculated in the
superior corner, the lips thick and refiexed, the umbilicus is scarcely visible. The
sculpture of the umbilical side consists in thick and coarse callous lines of growth. at
a regular distance from each other. H. 12 millim., br. 18 mill. A few specimens have
been ,collected at Klinteberg.

Fam. IX. UMBONID® Apams.
Gen. PYCNOMPHALUS n.‘)

Shell thick, trochiform or globose, the inner lip of the aperture with a thick callosity,
which like a ridge surrounds the umbilicus.

This genus has been placed amongst the Umbonide in consequence of the callo-
sity, which encloses the wide umbilicus. Most of the other genera have the umbilicus
completely covered by a far larger callosity as in Umbonium (= Rotella).

There is a genus Rotellina Dp Kontycox Faune II, m p. 92 from the Carboniferous
formation of Belgium, which according to the figure given, seems to agree nearly with
our, but as the descriptive letterpress expressly states that there is no umbilicus, I
have not been sure of the identity and could not refer the Gotland species to it.

Pitonellus Montrorr has also been placed with the Umbonide, but they have the
umbilicus completely covered up. The same is also the case with Umbonium helici-
forme Gotpruss from Paffrath.

As to the identity of this genus with Platyschisma see below in Pychn. acutus.

Of the genus Pycnomphalus I have found the following three species in Got-
land.

1. Pycnomphalus obesus n.
Pl. XV fig. 64—67.

Shell helicoid, with five ventricose whorls in a short spire. There are no orna-
ments excepting some indistinct, transverse lines, which are curved backwards. The
aperture is circular, the outer lip thin, the inner lip thickened through an accumula-
tion of the shelly matter, nearly five times as thick as in the outer lip. The umbilicus

1) IIvzvdg, dense, thick, dugadoc, umbilicus.
K. Vet. Akad. Handl. Band 19. N:o 6. 20

154 «G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

is open, narrow at its mouth, most widened in the midst of the shell. The columel-
lar tube is consequently of unequal width, being more narrow where the callosities are
opposite, and widening below them and in consequence its contours form zigzag lines
as shown in fig. 65. H. 16 millim., br. 23 millim.

Found in the limestone of Wialmsudd near Farésund and at Lansa in Faro.

2. Pycnomphalus acutus pn.
Pl. XVI fig. 1—s.
?Platyschisma helicites Sow. Siluria 4th Ed. pl. 34 f. 14—15.

Shell, trochiform with short spire of seven whorls. The surface is covered by
fine, densely set, equal stria, meeting in an acute angle from both the apical and the
umbilical sides, where the sharp, dividing keel is projecting on the median line of the
whorls. At regular distances there are deeper or more distinct transverse furrows,
dividing the small striz in narrow fields. The umbilicus is open and much wider
than in the preceding species. The aperture is transversally elliptical. The outer lip
widened into a prominent angular apex, forming the keel, the inner lip thickened in
its upper part, nearly thrice as thick as the outer lip. A very indistinct spiral line
accompanies the keel on its inferior side. H. 10 millim., br. 25 mill. Several speci-
mens have been found in the Trimerella limestone of Wialmsudd together with P.
obesus. It has also been found in the shales of Westergarn and Djupvik in Eksta and
in the limestone of Ostergarn, Ardre, Wisby (Kyrkberget) and Nyhamn in Lummelund.

It is possible, that this species is identical with the Silurian Platyschisma helici-
tes Sow. Sil. Syst. But I have not been able with any certainty to make out this
identity, as there are such conflicting opinions in the fourth Edition of Siluria, where
on page 162 a figure of it is given, quite different from that on plate 34 fig. 14—15.
Both can hardly represent the same species. The first figure rather resembles a va-
riety of Euomphalus Walmstedti, and the second, again, which, however, consists ot
mere nuclei, seems to coincide more with P. acutus. But if this be the case, that
species cannot be retained in the genus Platyschisma, as it is expressely stated that this
genus has »a very wide, shallow sinus in the middle of the outer lip»). There is not
the least trace of any sinus in the Gotland specimens.

3. Pycnomphalus trochiformis n.
Pl. XVI fig. 7.

Shell large, broadly conical, of at least seven whorls, slowly increasing in height’).
Sides even, without any convexity, of rectilinear outline. Surface of the only specimen
1) Mac Coy Pal. Foss. p. 533.
*) The ratio of increase in the only specimen is:
Whorls. Height. Breadth.
1 8 31
2 6 26
3 5 20
4
5

4 14
3 10.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 155

extant so much weathered, that no sculpture can be discerned, excepting some indistinct,
crescent formed transversal lines. Along the upper border of the whorls a narrow,
slightly elevated string is seen, being the uncovered portion of the acuminate ridge,
that divides the apical side from the umbilical. The later is almost flat. The aper-
ture is transversally elliptical and the umbilicus wide, surrounded by the elevated cal-
losity, which emanates from the thickening of the inner lip. H. 28 millim.; br. 32
mill. Only one specimen is known, belonging to the collection of the school of Wis-
by, derived probably from the upper limestone near that town.

Fam X. TURBINIDZ A.peEr.

In following the precedence of S..P. Woopwaxrp*) and partly also of Zirren’) I
place the following five genera within this family. Some of the shells, which I have com-
prised within the genus Oriostoma, have by DesHayes and most authors after him been
numbered with the Solariide. One of the latest authors, SroriczKa®*), does it on account
of the presumed similarity of its operculum to that of Torinia and the more so to
that of Omalaxis, with which recent genus also some of the paleozoic forms have been
regarded as identical. But besides, that nearly similar forms of opercula also occur in
other families, as the Siliquariw, the Vermetide and the Turritellide, there is another
circumstance which makes it probable that the paleozoic shells under consideration
cannot belong to the Solariide. It consists namely in the important feature that se-
veral of its species have retained the most evident traces of a nacreous layer, both in
the genus Oriostoma as well as in Cyclonema. Moreover the operculum is solid and
shelly not chitinous as in the former genera. These genera, which thus closer agree
with the Turbinide than with the Scalariide are the following.

Oriostoma Munier-Cuatmas, with short spire, surface richly ornamented by lon-
gitudinal carinz, crossed by variously sculptured, transverse strie. Operculum conical,
solid and shelly with narrow coils. Umbilicus large and open.

Cyclonema Hatt, with high spire, ornamentation of fine, slightly prominent lon-
gitudinal keels, crossed by equally fine, transversal strie. Operculum depressedly coni-
cal with large coils and hollow inside. No umbilicus or a very narrow one.

Trochonema Saurer, turbinate, whorls angular through several distantiated sharp
keels, umbilicus large, open.

Eunema Sauter, small, turriculated, with one or several narrow keels and other
sculpture, umbilicus closed.

Craspedostoma n. gen., shell globose, naticoid, with the lips widened to a broad
frame around the aperture, lower end of interior lip enlarged into an aliform appendix.

1) Manual of Moll. 2d Ed. 263.
?) Handb. Palzont. 1,2, 187.

2<3

3) Paleontologia Indica V, 249.

156 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Gen. ORIOSTOMA Munier-Cuatmas.

1814 Euomphalus Sow. p. p. Min. Conch. vol. 1, 97.
1864 Omphalotrochus MrEK. Rep:t. Geol. Survey of California, Paleeont. vol. I, 16.
1876 Oriostoma Mun.-Cuatmas Journal de Conchyliologie vol. XVI, 103.
1881 Polytropis De Koninck Faune Carbonif. II,m 107.

Shell discoid, with short spire, rarely high, whorls tubular, ventricose, joined, seldom
a little disjointed near the aperture, longitudinally sculptured with prominent keels, aper-
ture with thin lips without any sinus, generally continuous, umbilicus wide and open. In
several species the nacreous lustre of the interior shell strata is retained on the nucleus.
The operculum is caleareous and solid, on the inner side smooth with a thick, elevated
rim around the margins, outside conical, sometimes higher than broad, covered by a number
of spiral coils ornamented with exceedingly thin lines. Mostly large shells, but some species
also small.

Besides the above, in the list of synonyms enumerated genera, which have ex-
clusively or almost so been applied to the species of this genus, there is also a num-
ber of other genera, in which some of them have been included as in Turbo by Pic-
TET, Delphinula by Htsrncer and others, Trochilites and Helicites by ScHLoTHEM, Tur-
binites by WantenperG and ScuLoTHerm. Straparolus Monrrort might, according to
several authors, embrace species of this genus, but the first species described are not
known to have had any operculum and their ornamentation differs. If we strictly con-
fine ourselves to the species, which Sowrrgy, when he at first established his genus
Euomphalus, included into it, we must find that later created species such as E.
discors, E. rugosus, E. funatus etc. essentially differ from the former in having an en-
tire aperture without any slit as in those, which form the genus Euomphalus sensu
strictior’ and must be ranged near the Pleurotomaridx. Delphinula, employed by Hisry-
GER, is now applied to species from later formations and generally regarded as a sy-
nonym for Omalaxis, which has a chitinous operculum. Omphalotrochus MEEK may in
some degree be related to or even contain species of this group, but the name indi-
cates an affinity, which is not borne out by the evidence given by the operculum of the
Silurian specimens. Polytropis De Koy. seems, to judge of the expressions of this author,
at first to have been intended instead of Inachus (In. sulcatus His. is a Pleurotomaria), but
De Kontncx then cites Euomph. discors as the typical species and consequently the name
is synonymous with Oriostoma. The Devonian Oriostomata lately described by Ozntert,
as far as I am able to judge by specimens kindly sent from him, belong to the same
generic group as the Silurian, which formerly had been confounded with the Euom-
phali and both consequently must be placed in the same genus Oriostoma. The De-
vonian species however are all small and no operculum has as yet been found with
them.

The distinction between Oriostoma and Cyclonema, the next genus, is not quite
as clear as desirable, when the operculum is wanting. When an Oriostoma varies in
having a long spire, it nearly resembles a Cyclonema, but these never have the umbi-
licus as large as the former.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 157

In certain species of Oriostoma, which have a single longitudinal keel near the
suture, there is at first sight some resemblance with species of Euomphalus, but the
apertural sinus is here reduced to a short notch, which through the folding of the
aperture originates the keels. These notches never attain to such large dimensions as
the sinus in the Euomphalide and moreover they disappear in the body whorl of many.

The shells of this genus are amongst the most common in the Silurian strata of
Gotland and through their large numbers they offer a great variety of forms, which
make it a most difficult task to distinguish specific groups neatly from each other.
The great variability of the ornamentation and the almost imperceptible passages from
one form to another highly increase this difficulty. The oldest notions of the Swedish
Oriostomata are those given by Bromett in his Lithographia p. 32, 36, where several
are described under the name of Cornu Ammonis, but only one elearly enough to be
identified, viz. J@ 21, »Ejusdem generis Neritite majores» which is Oriostoma sculptum.

In the Lower Silurian formation of Sweden hitherto not a single species has
been found belonging to this genus. In Gotland the following sixteen species and va-
rieties have been detected and they may be divided in two groups.

A) with spire moderately prominent and the umbilicus deep and open.

1. Oriostoma discors Sow.

2. » var. rugosum Sow.
3. ©. contrarium n.

4. O. globosum Scutoru.

5. 10: » var. sculptum Sow.
6. O. coronatum n.

7. O. acutum n.

8. O. Wisbyense n.

9. O. angulifer n.

10. O. Roemeri n.

11. O. helicinum n.

12. O. alatum n.

B) with short spire and planorbiform shell, the whorls on the umbilical side
quite as much visible as on the apical one.

13. Oriostoma angulatum WaunLEnBerc.

14. O. lineatum n.

15. O. nitidissimum n.

16. O. dispar n.

Besides these species there is evidence of at least three species more through their
opercula, described below, but as no shell has been found to match them, they must
for the present be left undeterminated.

1. Oriostoma discors Sow.

Pl. XVI fig. 20—36, pl. XVII fig. 1—5.

Euomphalus discors 1814. Sow. Min. Conch. vol. I, 113, pl. 52 f. 1.
1857. AGassiz in Sowerby Gross Brit. Mineral Conch. 61, tab. 36.

158 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

1839. Sow. Sil. System, 626 pl. 12 f. 18.
1843. Morris Catal. Brit. Foss., 144.
1847. Murcutson Qu. Journ. Geol. Soc., 29.
1848. Bronn Nomenclator, 479.
1854. Morris Catal. 2d Ed, 247.
1855. Mac Coy Palzoz. Foss. 298.
1858. Fr. Scumimr Estland, 204.
1859. Sauter in Siluria 3d Ed. 548, pl. 24. f. 12.
1867. Linpstrom Nomina, 23.
1873. Sauter Catal. Cambr., 156.
Turbinites cornu arietis 1818. Wantenpere Petref. Suec., 68, pl. III fig. 9, 10.
1828. Hrs. Anteckn. IV, 257.
Delphinula cornu arietis 1829. Hts. Tabl. 10.
1831. Ip. Tabl. ed. 2, 8.
1831. Ip. Anteckn. V, 113.
Euomphalus cornu arietis 1837. Ip. Leth. Suec., 36, tab. XI fig. 6.
1841. Ip. Forteckn., 55.
1848. Bronn Nomencl., 479.
1858. Fr. Scumipr Estland, 204.
1867. Linpstrom Nomina, 23.

Straparollus discors 1850. D’Orsieny Prodr. I, 29.
Turbo cornu arietis 1850. In. ibid., 30.
Polytropis discors 1881. Der Kon. Faune Carbon. Belgique. I,m1, 107.

Shell discoid, spire short, or, in the variety called E. cornu arietis by WaAHLEN-
BERG, prominent, with six whorls, which are carinated on their inferior surface by
blunt, longitudinal keels of varying number and prominence, from three to eight in
the typical form. In the elongated variety there are three on the inferior surface,
but as many as eight on the umbilical one. The surface slopes from the lowest
keel towards the suture which is shallow. The keels are crossed by narrow, trans-
verse, undulated lines of growth, giving the surface an imbricated appearance. The
transverse strive of the umbilical surface are curved sigmoidally and have grown out into
thin, prominent lamella. The great amount of variation as to the ornamentation in
these shells may be gathered from the numerous figures given. The aperture is trans-
verse, its superior margin sigmoidally bent, the outer lip thin and notched or angu-
lated where the keels are formed, the inner lip is thick. The umbilicus is wide and
open and all whorls are visible. H. 23 mill. br. 73 mill.

It occurs at Lansa on Fard, at Wialmsudd on Farésund; in the upper limestone
beds of Wisby and in the shale of Wisby and most plentifully at Westergarn.

In the variety »cornu arietis» the umbilicus is relatively less wide and the course
of the striz on the umbilical surface is more straightly directed backwards. The
aperture is also more circular. H. 28 mill., br. 39 mm. Largest diameter of the aper-
ture 16 mill. It has been found at Lansa and Lutterhorn in Faré, also at Alnase by
Prof. P. T. CrLeve, in the crystalline limestone of Wialmsudd, in the canal near West-
6ds in Hall, Samsugn in Othem, Follingbo, Bara, Kristklint in Kapellshamn, Hérsne,
Martebo, in Kyrkberget in Wisby, at Walve ref, Westergarn and Klinteberg, thus chiefly
n the higher strata. The rule holds good in these, as in so many others, that the
spiral ridges are more prominent in small specimens or on the old whorls of the larger
ones and are apt to disappear on the larger and younger whorls.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 159

The variety figured pl. XVII f. 4 is in some way a transitional form to the
following.

2. Oriostoma discors Sow. var. rugosum Sow.
Pl. XVII fig. 5—10.

Delphinula 1811. Parkinson Org. Rem. III, 77, pl. VI f. 7—8.
Euomphalus rugosus 1814. Sow. Min. Conch. I, 113, pl. 52 f. 2.
1839. Iv. Sil. Syst., 626, pl. 12 f. 19.
1843. Morris Catau., 145.
1847. Murcurtson Qu. Journ. Geol. Soc., 29.
1848. Bronn Nomenclator, 481.
1854. Morris Catal. 2d Ed., 248.
1855. Mac Coy Paleoz. Foss., 298.
1867. Sauter Siluria, Ed. 4, 532, pl. 24 f. 13.
1871. Batty Charact. Br. Foss. pl. 21 f. 8.
1873. Sauter Catal. Cambr. Foss. 157.
Euomph. angulosus 1814. Sowersy Min. Conch. vol. I, 114, pl. 52 f. 3.
Helicites catenulatus 1818. Wautens. Petref. Suec., 72.
1828. Hts. Anteckn. IV, 237.
Delphinula catenulata 1829. Ip. Tableau ed. 1, 10.
1831. Ip. Tabl. ed. 2, 8.
1831. Ip. Anteckn. V, 114, tab. 1 fig. a.
Euomphalus catenulatus 1837. Iv. Lethea. 37, tab. XI f. 9.
1840. Ib. Forteckn., 55.
1858. Fr. Scumipr Esthland, 204.
1867. Linpstr6m Nomina, 23.
1876. Ferrp. Roemer, Leth. Geogn. pl. 14 f. 8.
1883. Quvensrepr Petrefaktenkunde Deutschlands, le Abth. 7r Bd, 397, pl. 200 f. 90
(not fig. 91).
Straparollus rugosus 1850. D’Ors. Prodr. I, 29.
Straparollus catenuiatus 1850. Ip. Ibid. 30.

Shell nearly discoidal, spire only a little prominent or turbinated, whorls six,
carinated by eight or ten longitudinal keels, interrupted on pretty equal distances by
large, sinuous lines of growth, which are elevated in a backwards reflexed fold at the
point where they meet the keels, giving in their totality an imbricate or roughly scaly
appearance to the surface. Between the larger lines, which are much distantiated,
the surface is sculptured by minute lines, parallel with them. The umbilicus is open
and the aperture circular with a continuous peristome of thin lips. H. 37 mill., br.
68 mill. The lips of the aperture are much unequal, the exterior one being prominent,
the interior, deeply insinuated, expecially at its superior corner, the distance between
both amounting to 28 millim. in one of the largest specimens. It occurs frequently,
though not so common as the former, in Faré, at Wialmsudd, Samsugn in Othem,
Lannaberg in Slite, Méner in Boge, Stor Wede in Follingbo, Martebo, Kalens Qvarn
and Galgberget near Wisby, in the shale beds of that town, Ostergarn both in the
shale and the limestone, Ardre, Bara hill, Linde, Klinteberg and Frdéjel.

The range of variability is very wide within this group. Along with shells of short
spire, long spired or turbinate shells occur, and together with those of rare transverse
imbrication, there are others which have it dense. The specimens from Ostergarn and
Klinteberg are commonly almost disciform, those from Samsugn with long spire and

160 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

transverse imbrication dense. The oldest form from the lowest beds of the marly
shale of Wisby (Pl. XVII f. 5—7) is turbinate, with only three longitudinal keels and
a low one around the umbilicus. The ornamentation is for the rest the same.

This Or. rugosum differs from Or. discors in the more distantiated, transverse
lamine and in their folds being considerably reflexed backwards on the keels. Such
a variety of O. discors as that figured pl. XVII f. 1—2, connects both.

3. Oriostoma contrarium n.
Pl. XX fig. 8—15.

Shell sinistral, turbinate, with six terete whorls. The apex is sunken and the ex-
treme tip is hidden beneath the next whorls, fig. 15. The surface is transversally and
obliquely striated by regularly distantiated lamellar ribs, often dividing in two and
again uniting, a little wavy in their edge, which is sharp and thin. They are curved
sigmoidally upwards towards the umbilicus. The aperture is obliquely ovate or even
circular with thin lips and continuous peristome. The inferior part of the exterior lip
is folded in and thus narrowing the aperture. The umbilicus is wide and large. It
is defined by a narrow ridge, which is most prominent in young or small specimens,
fig. 13, indistinct or only as a swelling in the older. The shell substance is thick,
especially in the body whorl. Owing to the different state of preservation the aspect
of the surface varies, being corroded in some and only the basal lines of the lamelle
left, fig. 14. H. 24 millim., br. 41 millim. Another specimen has in h. 24 mill., br.
23 mill.

It has been obtained from the shale of Wisby, from the limestone beds of Lansa
and Lutterhorn in Faréd, Wialmsudd, Samsugn in Othem, the canal of Westéds in Hall,
Kyrkberget in Wisby and Hoburg.

4. Oriostoma globosum Scutotuem.
Pl. XVII, fig. 24, 25, 29—31, pl. XVIII, fig. 24, pl. XX, fig. 16.

?Valuata sulcata 1776. Waucu, der Naturforscher, Neuntes Stiick, 278, tab. IV f. 5.
Delphinula 1811. Parkinson Organic Remains, 78, tab. V. f. 18. ;
Trochilites globosus 1820. ScuiotuEr Petrefactenkunde, 162.
Euomphalus funatus 1823. Sowrrsy Miner. Conch. vol. V, 71, tab. 450 f. 1 & 2.

1839. Ib. Sil. Syst., 626 pl. 12 f. 20.

1843. Morris Cat. Brit Foss., 144.

1848. Bronn Nomenclator, 479.

1849. Brown Illustrations of the fossil Conchology of Great Britain and Ireland, 81, pl.

XLII figs. 24, 25.

1854. Morris Catal. 2d Ed. 248.

1855. Mac Coy Pal. Foss., 298.

1858. Fr. Scumipr Geol. Estl., 202.

1862. MCoy Sil. Foss. of Ireland, 13.

1867. Satter Sil. ed. 4, 531, pl. 25 fig. 3.

1871. Baruy Charact. Brit. Fossils, pl. 21 f. 9a, 9b.

1873. Sautrer Catal. Cambr. Foss., 90, 157.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 161

Skenea funata 1828. Fuiemine Brit. Anim., 314.
Delphinula subsuleata- 1829. Hts. Tableau ed. 1, 10.
1831. Ip. Anteckn. V, 114, tab. I f. bb.
18315) iby Tabliceds 2:78!
Euomphalus subsuleatus 1837. Hus. Leth., 37, tab XI fig. 10.
1840. Id. Forteckn. 55.
1867. Linpstr. Nomina, 23.
Straparollus subsuleatus 1850. D'Or. Prodr., 30.
Turbo funatus 1850. In. Ibid. 30.

Shell moderately elongated, globular, with six ventricose whorls. The longitudinal
carine vary in a high degree as to their number, size and ornamentation according
to the different localities and to the size of the specimens. On the body whorl there
may be as many as 14, of which those on the apical side are the largest. As a rule
it holds good that each alternate keel is of the same size, one more narrow, sometimes
scarcely perceptible, being situated between a larger one. Each keel is composed by
a succession of imbricated,. more or less crowded folds, which at the outer lip haye
the aspect of shallow notches. The smaller longitudinal strix are thread fine, seldom
imbricated. Sometimes there are two of equal size beside each other. In young spe-
cimens the keels are smooth, not imbricated. The interspaces are crossed by trans-
verse lines, fine and coarse. In a variety from Hammarudd in Kraklingbo the keels
are low and sharp and the lines of growth continue more sharply defined than in the
typical forms, at regular distances. The same variety also occurs in Faro.

The aperture is circular, the lips are thin, the umbilicus is very narrow but
deep and confined within a sharp and prominent keel, outside which there is one still
larger, with a broad groove, scooped out between them. In several specimens the na-
creous lustre is still preserved on the nucleus, where the shell has peeled off. H. 37
mill., br. 53 mill.

The operculum, which has been found in situ in some instances, is disciform and
of a perfectly circular outline. See fig. 24. Its inner surface is bordered by an ele-
vated, narrow edge, section magnified pl. XVII f. 25. Inside this edge the smooth sur-
face is more or less excavated near the centre, for the rest it is flat. The exterior
surface is more or less elevated near the centre in an obtuse top, having, when seen
from the side, a faintly concave outline. The different relations in size may be found
from the following dimensions. Operculum from Westergarn: height 4 mill., diameter
13 mill. Operculum from the hill of Sandarfve: h. 4 mill. diamet. 14 mill.

In the sculpture of the spiral lines they all nearly agree with those figured on
pl. XVII fig. 25 and pl. XVIII f. 24. These are very tightly wound and their spi-
rality is evident only by following one of them, else they look as if concentric. They
are at least twenty whorls. The surface of these coils is obliquely crossed by a great
number of smaller, also elevated lines or coils; the uppermost are highest and more
prominent, the others decreasing regularly. This peculiar ornamentation is best shown
in thin sections, enlarged under the microscope as seen in the figure 24 pl. XVIII. It
is then evident that the spiral coils form narrow ridges, which are nearly vertical to
the diameter of the operculum and that the ornamental lines are most numerous on

the lower surface of the coil, the uppermost being largest and more wide apart. As
K. Sy. Vet.-Akad. Handl. Bd. 19. Nio 6. 21

162 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

to its chief mass the operculum consists of a compact, dull, gray limestone nearest
the outside, but the interior mass is converted into clear, crystalline calcareous spar
and distinct lines in this indicate special strata of growth of which it is made up.

As seen in fig. 25 pl. XVII thin and narrow coils are alternating with larger
and the partitions are more deeply cut, than in any of the other forms of opercula
and the lobes directed vertically.

O. globosum has been found in the shale beds of Wisby, Westergarn, Stora
Carlsé, Petesvik, Burge in Fardhem, at the canal from Wisne myr, Ejmunds 4, Slite,
Hall, Lutterhorn and Lansa on Faré, Hammar in Kraklingbo, in the limestone beds of
Gothemshammar, Ganthem, Rute, Wialmsudd, Samsugn, Martebo, Hoérsne, Klinteberg,
Lilla Carlsé and Sandarfve kulle, Frdjel.

The operculum has been found in the shale of Wisby, Follingbo, Sandarfve kulle,
Eksta (Djupvik), Westergarn, Linde klint and Slite.

It seems that this common and widely spread shell has been first described by
Watcu as cited above, when he writes »Von der versteinten valuata sulcata des Rumpus.»
»Das Original des gegenwartigen kommt... mit der unter Num. 5 daselbst (in Rumpu’s
work) befindlichen valuata sulcata sehr genau tiberein. Das Petrefact ist aus dem
Mecklenburgischen, weiss von Farbe und hart versteint». The accompanying figure may
well be accepted as representing Or. globosum. Through the liberality of Professors
Breyricn and Dames of Berlin I have had for inspection the very original specimen of
Scutotuem’s Trochil. globosus, which is kept along with his other collections in the
Museum of the University of Berlin. On the original label is written »aus Gothland
in Uberg (angs) Kalkstein». It is badly preserved, to a great part imbedded in the
rock, a ball of limestone from the shale beds, possibly of Wisby or Stora Carlsé. It
belongs to a variety with only few keels on the umbilical side and the transverse strix
much distantiated. It is indeed quite the same which later by Sowgersy was named FE.
funatus, which name, although long used, must give way for the older of ScHnoTHEIM.

I cannot decide whether Euomph. funatus Ercawaup Leth. rossica I, 2 p. 1152
belongs to this species or not.

5. Oriostoma globosum, var. sculptum Sowersy.
Pl. XVII fig. 41—42.

Nerititee majores, striati et juxta longitudinem spirarum quasi sulcati, BRomeLL 1738 Lithogr. Suec. p. 36.

Delphinula funata 1829. His. Tabl. ed. 1, 10.
1831. Ip. Ibid. ed, 2, 8.
1831. Ip. Anteckn. V, 114.
Euomphalus funatus 1837. Ip. Lethea, 37, but not the figures pl. XI fig. 11, which are copied from Sowrr-
BY’s HE. funatus Min. Conch. pl. 450.
1840. Ip. Foérteckn., 55.
Euomphalus sculptus 1839. Sow. in Sil. Syst., 626, pl. 12 fig. 17.
1845. Morris Catal. Brit. Foss. 145.
1848. Bronn Nomencl. 481.
1854. Morris Catal. Brit. Foss., 248.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 163

Euomphalus sculptus 1855. Mac Coy Paleeoz. Foss. 299.
1862. Ip. Sil. Foss. Ireland, 14.
1867. Satter Siluria 4th Ed. 532, pl. 9 f. 27, pl. 25. f. 2.
1873. Ip. Catal. Cambr., 90, 157.
Turbo momus 1850. D’Ors. Prodr., 50.
Euomphalus lautus M. Coy, Sil. Foss. Ireland, 14, pl. 1 fig. 12 belongs possibly also to this species.

Shell with short or only slightly prominent spire of five ventricose whorls. The
surface is covered by numerous, closely set, revolving lines, alternately large and nar-
row, the larger attaining twice the size of the lesser. They are generally so densely
packed that there is no space left between them. The transverse lines of growth form
on them crescent shaped notches, one for each line. The aperture is circular, the lips
are thin and the umbilicus is narrow and open. H. 34 mill., br. 44 mill.

There are so many transitional forms, connecting this species with the former
that it is indeed a necessity to merge them into one and same species. In Siluria,
3d Ed. p. 236 Satter says that Eu. sculptus »appears to be only a variety of Eu.
funatus». R. Evruermpce jr (Ann. Mag. N. H. 5th Ser. vol, 7 p. 31) also inclines to
regard both forms as identical, though his opinion that »sculptus» may only be the young
condition of Eu. funatus cannot be upheld, as we have specimens of sculptus quite as
large as »funatus». Moreover the opercula are not different. I have such from Djup-
vik in Eksta and they only slightly differ from that figured on Pl. XVII f. 25. The
dimensions are in one specimen: height 3 mill., diam. 9 mill.

The chief distinguishing feature of this Or. sculptum from Or. globosum is the
great number of its revolving keels, which in some specimens amount to as many as
fifty. Through their proximity or their distance many gradations in sculpture arise.
The same is the consequence of the different fineness or coarseness of the transverse
strie. In some these striew are prominent and distantiated, in others fine, perhaps corro-
ded, the first coinciding with the presence of distantiated revolving keels, the later
with the narrow and numerous keels. But however dissimilar in sculpture, they all
have the same operculum and around the narrow umbilicus there are two elevated
keels as in Or. globosum. The more globose shells have a greater number of keels,
closely crowded and there is consequently a continuation of frills on the surface.

In specimens from the same locality the amount of variation, especially in the
sculpture of the revolving keels, is very great, nay, even in the same specimen sculp-
tured keels alternate with almost smooth ones. But these, especially in the »sculptum»
forms, show a very fine and microscopically minute, transverse ornamentation, which
of course is through corrosion destroyed in exposed localities and thus causing a smooth
surface. Of the »sculptum» group there may be thus discerned at least two minor sub-
divisions.

1. The shell has no less than fifty longitudinal keels, but in common with the
other varieties a belt near the suture without any revolving keels and in the wide and
deep umbilicus, environed by keels. This has been found in the canal near Wests
in Hall, at Faérdsund, and in some specimens at Samsugn, Othem. A nearly similar
variety occurs in the shale of Djupvik in Eksta and Wisby, with some 25 longitudinal

164 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

ridges and more finished sculpture than in the former. Also found at Lansa and
Lutterhorn in Faré, Sandvik at Fardésund, Klinteberg and the shales of Stora Carlsé.

2. There is an intermediate variety between this sculptum and Or. globosum from
Martebo, and from the marly limestone beds above the shales of Eksta and also Lilla
Carlsé. It has the ridges distant on the apical surface, crowded on the umbilical, thus
combining both the funatus and sculptus characters in the same specimen. This has
also been found in Martebo, Samsugn, Slite, Medebys in Hall, Sproge and Hoburg.

Although Hismvcer copied Sowersy’s figures of E. funatus, as seen by comparing
their figures’), he, in his own collection, partly gave that name to the shell which So-
WeERBY later denominated as Eu. sculptus. The English authors refer to »sculptus» spe-
cimens with numerous crowded keels, but in that number possibly several different
species may have been confounded. M’Coy Brit. Pal. Foss. p. 299, says »that the ab-
sence of the transverse scale like sculpturing and the... more numerous ridges, easily
separate this from the E. funatus», It,is indeed most bewildering to discern in all
this mass of similar and yet, as their opercula prove, specifically different forms and
mistakes can scarcely not have been avoided in my arrangements of them.

6. Oriostoma coronatum n.
Pl. XVII fig. 11—16, 18—22.

Shell large, globular, turbinate, spire short, whorls five, ventricose, angular through
the many projecting keels with perpendicular walls between them. On the body whorl
there may be seen as many as seven or even nine keels on the exterior side from the
suture to the highest point of the umbilical side and on that side at least five. Smal-
ler keels intervene between them. The large keels are crenated by blunt spines, for-
med by regularly distantiated, oblique folds, causing the often ocurring cone in cone
structure. Where these folds are perfect, their edges are considerably thin, a little
forward bent or generally having the shape of small crescents. The interstices, which
are nearly five times as large as the keels, are almost smooth, transversally striated
by microscopically minute lines, directed obliquely, or nearly perpendicular, backwards
from the suture to the umbilicus. The aperture is circular, the outer lip thin, the in-
ner lip thickened, almost reflexed. Around the umbilicus there is a deep and broad
groove (fig. 14) bounded by two high and prominent keels, of which the interior one
is short and forms the nearest enclosure of the narrow, spirally wound umbilicus.
H. 40 mm. br. 53 mm.

The operculum is very frequent and has in some instances been found in situ.
It is button shaped, perfectly circular, more or less elevated. The dimensions are in
four specimens from Ostergarn as follows:

1) Diam. 20 mm. Height 8 mm.

2 ) » 20 » » 10 aay
3) » 15 » » (Riseo6)
4) » Pil » » 6 »

1) SoweRBY Miner. Conchol. pl. 450 fig. 1 (the uppermost one) and fig. 2 (but reversed and restored in
Lethea 1. c.),

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 165

The inside is bordered by an annular callosity (fig. 18) and the enclosed area
is glossy, sculptured by numerous, microscopic striae, concentric in a zone nearest the
border, in the centre spirally curved, where also the surface is somewhat excavated.
On the outside the numerous coils are rather flat and broad, as shown in fig. 16, on
their inferior face ornamented with some fine, concentric strice below a larger one.
Their appearance in a transverse section is given in fig. 22, to be compared with that
of Oriost. globosum in fig. 25. The lobes of the sectioned coils are broad and short,
with low divisions between them and their tops only finely jagged by the parallel lines.

This shell, as well as its operculum, has been found most numerous in the lower
limestone beds of Ostergarn, also in Ardre, Gothem, in the Rhizophyllum beds near
the church of Lau, and in the limestone beds of Lindeklint.

It is distinguished from its congeners through its more richly sculptured keels,
nearly smooth interstices, only finely sculptured and by the peculiar operculut.

From the subjacent shale beds, such as, they are in the canal of Wisne myr in
Fardhem, I have obtained specimens of a shell nearly resembling O. coronatum. In
some, however, the sculpturing is intermediate between this and O. funatum.

From Martebo numerous specimens of an operculum have been obtained, which,
however deviating, still, through certain common details of shape, prove to be related
to the operculum of Or. coronatum. Pl. XVII figs. 32—-35. The shell to which it
has belonged is for the present not known, though the operculum is far from being
rare. In its form it resembles as nearly as possible the modern artillery projectiles,
being elongately conical in outline, fig. 32. They commonly have the same height as
the diameter or sometimes higher. Some are constricted transversally along the median
line. The dimensions of three specimens are:

1) Diam. 13 mill. Height 16 mill.
2) » 13 » » Wil »
3) » LSS Vg » 10.»

The coils on the outside are directed obliquely outwards or nearly parallel with
the diametral axis of the operculum and are considerably shorter and broader than
those of Or. globosum.

The narrow, ornamental lines which are crowded on these coils, fig. 54, are most
numerous and prominent on the inferior side, short and scarce on the upper half
of the coils. On the inner side the annular edge is prominent, the centre deeply ex-
cavated and the spiral distinct. A similar operculum has also been found in the up-
per limestone beds of Slite.

Mr Rog. Erueripcer jr has described and figured") several opercula of which some
are identical with the Gotlandic. Figures 9 and 9@really represent one of the conical
opercula from Martebo which I once sent to the British Museum. In fig. 12 an oper-
culum is seen, nearly corresponding with that from Westergarn, figured in my plate
XVII fig. 24. Fig. 14 probably represents one of the »sculptum» varieties, as ETHERIDGE
also believes, though with some hesitation. But it is only the impression of the inner

1) Ann Mag. N. H, 5th Ser. vol. 7, p. 25 pl. IL.

166 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

side of the operculum on the limestone or shale, which forms the nucleus of the shell.
That it is only a cast and not the operculum itself, may be found by comparing the
inside, drawn in fig. 9 of Erneriper’s plate, with fig. 14. Quite similar impressions
have been found in several specimens in Gotland. The Oriostomata figured by the
ETHERIDGE in figs. 10—11, much resemble O. sculptum, but the opercula seem to deviate
in shape as well as in sculpture from that, which with absolute certainty is known as
belonging to that species. The operculum, fig. 13, is possibly identical with one from
Hogrin. Mr Frep. Smirue has also given a notice with figures »On the opercula of
the Silurian Gastropoda» in the Proceedings of the Cotteswold Naturalists Field Club
for 1877—78 p. 62. The specimens figured are evidently badly preserved and belong
to some unknown species, the shell of which resembles Or. sculptum, but the sections
given of the operculum show (figs. 3—4) that it cannot belong to that species.

Barty’) has given a figure of the operculum of »Euomphalus funatus SowrrBy»
but it seems to be different from that ,described above, and rather more loosely coi-
led, resembling that in fig. 44 pl. XVII of the present memoir.

Lately Warrraves”) has described two opercula, of which, at least one, pl. Il f.
11 & pl. VI f. 7, comes near to that of Or. coronatum. The second operculum, pl.
III f. 10, again, is nearly related to those of Cyclomena described below.

7. Oriostoma acutum n.
Pl. XVII fig. 37—40.

Shell globose, turbinate, with spire of six ventricose whorls, angular through the
projecting, narrow, revolving keels. On the apical surface there are three keels, sepa-
rated by large interspaces, on the umbilical side they are much crowded, amounting to
ten before the first umbilical ridge is attained. Between this and the interior umbili-
cal ridge some five or six smaller ridges lie in a gently excavated, large groove. The
innermost ridge closely environs the deep and narrow umbilicus. All these revolving
keels are almost smooth, with sharp or rounded edge, only finely notehed by minute,
transverse striw. These are in the interstices directed backwards and so fine that only
a few, regularly distantiated ones are perceptible without a lens. Between them the sur-
face looks nearly smooth, but is in reality finely striated. The aperture is circular
and both lips are thin. H. 37 mill., br. 45 mill.

But for the find of the operculum of this shell in situ, it might easily enough
have been mistaken for a variety of O. globosum, from which it, however, differs
through the minute, transverse striae, the regular angularity of its apical side and the
regularity of the umbilical funnel. The operculum is acuminately conical, nearly of
the same height as breadth. The inner side is almost flat, the bordering edge is nar-
row and low, the central whorl is nearly on a level with the other surface and through
corrosion any sculpture, if formerly extant, has been destroyed. The coils on the out-
side are exceedingly narrow and close. They are formed like the sharp, thin, knife like

1) Figures of Charact. Brit. Fossils pt. III pl. 21 fig. 9 b.
*) Geol. Survey of Canada. Palzeoz. Fossils, vol. II pt I, p. 33.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 167

whorls of a screw, giving the outline of the operculum a serrated appearance as shown
in the sections 39 & 40. They are directed rectangularly to the longitudinal axis of
the operculum or only slightly curved upwards. They are quite smooth without any
smaller, ornamental lines. The dimensions of the operculum are in two specimens:
ACriteisnt 11> walle Br.) 12:
B. » 10» yeas

In Martebo almost the same type of operculum has been found detached without
any shell pertaining to it. Pl. XVII fig. 36. It deviates, however, in having the coils
more distantiated.

Or. acutum has been found in many fine specimens in a seam of marly limestone
at Slite, along with several opercula, of which one im situ. It has also been found in
a few specimens at Linnaberget of Slite.

With an operculum so deviating from that of the other Oriostomata, it may in-
deed be questioned whether this species does not belong to another generic or subge-
neric division, what must be left for future researches to decide.

8. Oriostoma Wisbyense n.
Pl. XVII f. 26—28, 45—46.

Shell globular, turbinate, small, of six ventricose whorls. There are only few
longitudinal keels, two larger on the apical surface, the lowest leaving a smooth belt
between itself and the suture. They are sharp, narrow and prominent, a little jagged
by irregular notches. Next them follow at equal distance two smaller keels around
the median line of the body whorl and then on the umbilical side a large belt inter-
venes, with only faint indications of a few longitudinal lines. Around the umbilicus
two large keels leave between them a nearly smooth zone, only finely transversally
striated. The transverse strie are gently inclined backwards, somewhat thick, swollen,
in other parts fine. All specimens, found in two localities, agree in all particulars and
are thus constant in their characters. The umbilicus is wide and deep, showing all
whorls. H. 18 mm., br. 18 mm. Spec. B. H. 14 mm., br. 17 mm.

The operculum, which has been found in situ in one specimen and in several
detached specimens, is in the largest specimen of a combined cylindrico-conical shape,
being from the base and a while upwards cylindrical, then at the top changing into a
conical shape. The inner side is bordered by a rather broad and elevated edge, the
enclosed surface smooth, deeply sunk towards the centre, where the whorl is situated.
The numerous coils of the outside are more distantiated than in the preceding, with
their edges directed upwards. All striw decorating them have now disappeared, if
once present, and in a section the whorls consequently only show as distantiated, blunt
teeth. H. 5 mill., br. 12 mill. One specimen, pl. XVII f. 47, possibly belonging toa
different species is elevated and regular, acuminately conical, h. 6 mill., br. 7 mill.
From the shale of Wisby numerous opercula have been found, closely resembling those
now described, pl. XVII f. 43—44, and almost entirely changed into iron pyrites. Their
coils are however more thick and less numerous. When seen in a section they are nearly

168 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

horizontal, triangular. The contour of the whole operculum is also more cylindrical.
The inside is a little more deepened than in the others. The shell to which it has
belonged is not yet known. H. 8 mill., br. 8. mill.

Oriost. Wisbyense has been found in the middle limestone stratum of Wisby and
at Kalens Qvarn.

9. Oriostoma angulifer n.
Ph RX fer 17-221

Shell turbinate, globular with moderately elongated spire, of six angular whorls,
the lower surface of which forms the spire into an evenly sloping cone, intersected by
the narrow and deep suture. There are from three to four fine and acute keels on
the body whorl, one near the sutural groove, one a little below the median line of
the whorl and one around the umbilicus. Between the two later there are on smal-
ler specimens one more and indications of yet smaller ones. The transverse striation
of the surface is microscopically minute and consists of nearly vertical, straight strie.
The aperture is polygonal, higher than broad with thin lips. The umbilicus is wide
and open. H. 6 mill., br. 8 mill.

Six specimens have been found in a soft, gray limestone from a canal near Her-
revik in Ostergarn. This little shell comes near to Or. Wisbyense through its few
keels and the deep umbilicus and also reminds of Oriostoma angulatum with its an-
gular contour, fine ornamentation and deep suture.

10. Oriostoma Roemeri n.
Pl. XVIII f. 22—29.

Euomphalus cornu arietis 1838. ANGELIN Museum Paleont. Svecic. W 10.
Euomphalus funatus 1867. Lixpstrom Nomina, 23.
1876. Ferrv. Roemer Leth. Geogn. Atlas pl. 14 f. 12.

Shell turbinate, globular, with six ventricose whorls. The longitudinal ornamen-
tation predominates entirely and the surface is consequently covered by chord like
keels, going close from the suture to the umbilicus, as many as 43 in some specimens.
They are all nearly of the same size, only a few narrow are mingled with them. They
continue without interruption close to the suture, without there leaving any zone free.
The transverse striation is visible as scaly, crescent like indentations on the revolving
lines, which sometimes are as if cut up in a great number of thin laminw. These
transverse imbrications vary much as to proximity and shape, being, when close to-
gether, only as lamellar crescents, when more wide apart, as longitudinal tubes, cone
in cone shaped. There are no ridges around the umbilicus, more elevated than the
other ridges. The umbilicus is narrow and partially hidden by the reflexed border of
the inner lip. The aperture is circular and both lips are thin. The shell is very thin
and it is almost impossible to find a specimen which is not crushed or distorted. On
the nucleus fine traces of the interior nacreous coating are seen. H. 30 mill., br. 36

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 1[9. N:o 6. 169

mill. This is the common proportion, but in a few instances the shell is so much
elongated, as to be higher, than broad, fig. 25, h. 40 mill., br. 34 mill.

Of the operculum of this species the State Museum in Stockholm possesses three
specimens in situ, of which two are too fragmentary for description. In one shell
there is the impression of the interior side on the nucleus. <A cast in plaster of Paris
shows that this side nearly resembles that figured on plate XVII fig. 35, the central
whorl being larger, the marginal rim flattened and the central concavity not so deep.
It is probable that the outer side, which is not preserved in any specimen, also re-
sembles that of Or. globosum.

This species is very common and is indeed the most characteristic one in the
shale beds around Wisby and also in the overlying limestone. A few specimens
have also been found in the shale beds of Gnisvard and Westergarn, proving the con-
temporaneity of these strata with those of Wisby. There are also single specimens
from the upper and lower strata of Hallshuk.

Or. Roemeri, which easily might be confounded with some of the varieties of
Or. sculptum, differs from them through the continuity of the longitudinal ridges close
to the suture, while they are somewhat more distantiated in the later and there is a
space left free without any revolving lines between the lowest keel and the suture.
The umbilicus is narrow in Or. Roemeri, wide and open in O. sculptum and environed
by two higher ridges, while in Or. Roemeri all ridges are of the same size.

Besides the opercula, which with absolute certainty can be referred to the prece-
ding four species or are most nearly related to them, there are some others which
belong to unknown species of other genera, also unknown, but probably of the same
family. They may be described here in connection with the former.

1. Pl. XVII fig. 53—55. Four specimens of this variety have been found in
the middle limestone beds of Wisby. They are regularly circular, depressed, nearly
flat, thin, attaining their largest thickness around the borders and at thinnest in the
centre. Section fig. 54. The coils on the outside are rather irregular or, as it were,
occasionally evanescent, thick and coarse around the margins, narrower and more indi-
stinct near the centre. The marginal coils are obscurely ornamented by finer, con-
centric lines. On the inside, which is shallow and concave there is no elevated annular
rim as in the preceding type, the whole surface is sloping without interruption, smooth
and glossy, to the centre, where a broad, faintly distinguished whorl is seen. Diam.
13 millim.,,thickness of margin 2 millim.

2. Pl. XVII fig. 56. <A single specimen with the inside affixed to the rock has
been obtained from Samsugn in Othem. It is of obovate outline, flat, the numerous
coils are coarse and angular. A section, fig. 56, reveals that they are narrow lamelle,
inwards bent, at largest near the margin and diminishing towards the centre. It is
thickest along the margin. Longest diameter 18 millim., the shortest one 15 mill.,
thickness at the margin 2 millim.

3. Two specimens from the upper limestone of Hogrin. The outline is obo-

vate, the outer side, the only one accessible, is entirely flat, without any prominence
K. Vet. Akad. Hand]. Band 19. Nio 6. 22:

170 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

near the centre. It is extremely thin, more so than in the preceding two forms. The
coils are narrow, numerous and regular. Their sides are ornamented by numerous, thin
and narrow lines, nearly parallel with the coils, but sectioning them in slight obliquity.
Longest diameter 12 millim., shortest diam. 10 mill. Thickness of margin scarcely 1
millim.

If these three forms of opercula belong to a common generic type, as I think,
the following one differs so essentially from them, that it must be regarded as belong-
ing to an other genus, which for the present is quite as unknown as the former.

4. Pl. XVII fig. 57. From the shale beds near Wisby four specimens of the lar-
gest operculum known in Gotland, have been obtained. But only the outside is visi-
ble, the extremely thin shell firmly adhering with the inside to the soft shale. It is
circular, flat, covered by thick laminar, elevated, spirally wound coils, in all twelve.
They have broad bases and obtuse tops. They leave between them deep interspaces,
nearly as large as themselves and they lean with their tops towards the centre. The
largest diameter is 32 mill. and it must consequently have appertained to a very large
shell, possibly to Cyclonema? giganteum, of which a few specimens are found in the
same beds.

The opercula of the Oriostoma pattern have sometimes been compared with
those extant in several recent genera as Torinia and Omalaxis. The operculum of
Torinia is, however, constructed upon a quite different plan, its inside is wholly dis-
similar, protruding in the centre in a rod like prolongation, while the operculum of
the paleozoic shells is sunken in the centre. Moreover, both Torinia and Omalaxis
have entirely chitinous opercula, whilst the palwozoic ones evidently from the beginning
were shelly. I have not found any other opercula resembling the paleozoic ones more
than that figured by D’Orsieny in his »Paléontologie Frangaise, Terrains Crétacés», pl.
186 bis, f. 183—17 and which, according to him, |. c. p. 228, has belonged to unknown
species of Turbo. It comes nearer to those of Cyclonema, than those of Oriostoma.
D’Orpicny remarks that the coils are »trés rapprochés, comme chez les Trochus pro-
prements dits». And, in fact, the opercula of Cyclonema, of which see below, in a
nigh degree resemble the operculum of the Trochoid Livonia as to the outside, espe-
cially in the ornamentation by fine, oblique lines.

11. Oriostoma helicinum n.
Pl. Il fig. 27—31, Pl. XX fig. 30—33.

Shell globular, heliciform, with short spire ending in a blunt point, whorls four
and a half, convex; suture shallow. Ornamentation consisting only of a succession of
fine, transverse lines bending backwards on the median line of the last whorl and then
again forwards on the umbilical side, very close and with smooth interstices. They
are arranged as it were in small groups divided through shallow furrows which give
the shell a wavy contour. There are absolutely no traces of any longitudinal lines even
in the best preserved specimens and the surface of the whorls is glossy and shining

KONGL SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 171

with a brownish tint. In other specimens again there are very distinct bands of the
original colour left, transverse, at regular distances, brown on the white surface of the
shell, parallel with the sculptural lines. The aperture is circular and its rim not con-
tinuous, interrupted at the interior lower corner. Outer lip thin, the interior one with
a somewhat callous border, umbilicus narrow and deep, entirely open and defined along
its periphery by a low and narrow ridge, which inwards sinks perpendicularly and
meets the sloping funnel of the umbilicus.

Dimensions: height 15 millim., breadth 18 millim. Aperture: high 11 millim.,
broad 10 millim.

From Samsugn in Othem, the canal near Westdds, Halls huk, in the uppermost
stratum and from Wialmsudd.

12. Oriostoma alatum n.
Pl. XVI fig. 14—19.

Shell disciform, whorls rather transversally dilatated, increasing rapidly in width
from the minute apex of three whorls. Whorls in all six. A narrow, laminar, sharp
edged keel divides the umbilical and the apical surfaces and thus gives the shell a
slight resemblance to Pleurotomaria alata and the allied species. But in this species
the laminar keel is solid and the transverse stria continue in the same direction on
both sides of it. Parallel with the keel there run some five narrow, thread fine lines,
equally distantiated on the apical side and, likewise on the umbilical side, five, though
more indistinct. The transverse striw are distinct, rather coarse and regularly directed
backwards. The aperture is transverse, obovate, the outer lip on the middle of its
height thickened by the keel, else thin, the interior lip thin, only expanded and thicker,
where it joins the whorl. The umbilicus is wide and so open that all whorls are
seen inside it. Specim. A, h. 14 mill., br. 23 mill.; B, height 10 mill, br. 24 mill.;
sp. C, h. 14 mill., br. 44 mill. One specimen has been obtained from the middle li-
mestone strata near Wisby and three from the higher strata of Kyrkberget in Wisby.

13. Oriostoma angulatum Wautenszerc.
Pl. XX fig. 34—41.

Aelicites supra-angulatus 1818. WaunLEeNBERG Petref. Tell. Sv., 72}).
Helicites angulatus 1818. Ib. ibid., 73.

1828. His. Anteckn. IV, 237.
Euomphalus angulatus 1829. Ip. Tableau ed. 1, 10.

Leslee iw. ib. ted: 2, 9s

1831. Ip. Anteckn. V, 114.

1848. Broxn Nomencl., 478. .
Inachus angulatus 1837. Hustneer Leth., 37, tab. XI f. 12.

1840. Ip. Forteckn., 55.

1867. Linpstr. Nomina, 23.
Euomph.? supra-angulatus 1837. His. Leth., 37.

1848. Bronn Nomencl., 482.
Straparollus angulatus 1850. D’Ors. Prodr., 30.

') Errore Helic. supragranulatus pro Hel. supraangulatus apud Bronn Nomenclator p. 572, 1848.

172 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND P'TEROPODA OF GOTLAND.

Shell discoidal, planorbiform, spire of eight whorls, depressed or only slightly
prominent. Whorls cylindrical, terete with several sharp keels, which are more pro-
minent and distinct in young specimens than in older, where they are more or less
obliterated. On the apical side there are two sharp and prominent, narrow keels, lea-
ving a flat band between them, one close to the suture, the other and larger on the
outside. Between the interior keel and the next whorl a deep, narrow groove is going
and the innermost apical whorls are in many instances sunk as a shallow depression.
The middle of the body whorl and also of the others is encircled by a highly acute
keel and on the umbilical side there are at least three such, forming between them
sharply marked facets, of which the lowest is abruptly turned down. On the umbi-
lical side there are thus at least four different faces. The apical keels disappear du-
ring the continued growth of the shell and instead of the seven original keels there
are on the body whorl finally only four or five on the umbilical side. The contour
of the whorls is, when all keels are present, a regular octogon, fig. 37, as the surface
between the keels is nearly straight or only slightly concave. The fine, transverse striz
run almost straight down over the keels, only a little bent forwards on the keels. In
fullgrown or large specimens the aperture is circular and the umbilicus is wide and
open, more so than in most of the other shells. There is some variability, for instance
in several specimens from Follingbo, where the whorls on the apical side are so much
sunk, that there is a spire on the umbilical side. In some there are no keels at all
on the larger whorls, not even near the umbilicus, and the whorls are uniformly tu-
bular. There is also a tendency in the body whorl to disjoint itself from the other
whorls, as remarkable in specimens from Farésund. Br. 66 mill., h. 18 mill.

The figure given by Hisincrr of his Inachus angulatus is bad and exaggerated.
There are four specimens with Histvcer’s hand named thus in his own collection, of
quite the same variety as mine. But the type specimen of his figure is not amongst
them, it is probably from the Museum of Upsala. That Wautenpere’s Helicites supra-
angulatus is identical with this species, is corroborated through his type specimen,
which I have been able to see through the kindness of Prof. Cimve and it quite agrees
with the large specimens from the limestone of Wialmsudd.

SALTER’) says that »Inachus angulatus Hrsrnvegr, is probably an extreme form of
the group (of Trochonema) with a greatly depressed spire». This statement can hardly
be accepted and the fossil in question is here retained within Oriostoma. It may
through future researches be decided whether it should not rather be placed with the
Euomphali, from which it, however, differs in the want of any notch in the last whorls
and the concomitant ridges. The transverse strize are, moreover, bent forwards on the
keels, not backwards.

This is a very abundant and well preserved shell in some localities: Lansa and
Lutterhorn of Faré, Wialmsudd and Sandviken at Farésund, Lanna near Slite, Sams-
ugn in Othem, Qvarnbacken of Slite, Kylley, Enholmen, Barabacke, Follingbo, Kalens
Qvarn, Wisby in the uppermost limestone, Klinteberg, Stora Carlsé near Altaret. It
thus occurs exclusively in the uppermost, crystalline limestone.

1) Geol. Survey of Canada, Canad. Org. Remains, Decade I, 27.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. hee

14. Oriostoma lineatum n.
Pl. XX fig. 42—44.

Shell discoid or nearly so, with short spire of five ventricose whorls. The suture
is deep and the surface is uniformly lineated by thread fine, elevated, narrow, longi-
tudinal ridges continuing without interruption from near the suture to the upper mar-
gin of the umbilicus. They are a little larger and more distantiated on the rounded, middle
line of the shell. The interstices between them are nearly smooth and the transverse
lines which cross them are straight and minute, only in the umbilical opening they
are more prominent. The aperture is circular with thin lips and the inner one clo-
sely moulded to the preceding whorls, the umbilicus is wider than in any of the other
species, with all whorls visible. H. 16 mill., br. 44 mill.

In the Paleontological State Museum of Stockholm twelve specimens are preser-
ved, all from the limestone of Klinteberg, and four from the uppermost limestone of
Fréjel. From the limestone beds nearest above the oolite in Wamlingbo I have ob-
tained a fragmentary Oriostoma, which somewhat resembles the preceding. The trans-
verse striz are wavy and coarse, and there seems to be a deep groove along the su-
ture on the apical side. It forms probably a new species.

15. Oriostoma nitidissimum n.
Pl. XXI fig. 4—10.

Shell small, disciform, apex on a level with the outer whorls; five whorls in all,
evenly rounded without any keels or longitudinal striation at all. They are transver-
sally and most finely striated by straight lines, running to the open umbilicus. The
suture is shallow. The aperture circular and the lips thin. H. 3 mill, br. 8 mill.

It is very common in the red limestone of the hills of Sandarfve and Linde and
a few specimens also from the gray limestone. A shell occurring in the limestone of
Stor Wede in Follingbo is probably only a variety of this. It is more ventricose in
the body whorl, the umbilicus is more narrow, and the perpendicular striation is not
so dense as in the other form.

16. Oriostoma dispar n.
Pl. XXI fig. 11—14.

Shell planorbiform, low on the apical side as well as on the umbilical one and
excavated on both sides. Whorls five and a half, rounded on the apical side, flatte-
ned on the umbilical one and there provided with a prominent keel in the margin.
The transverse striz are distantiated on the umbilical side, finer on the apical side,
and directed at first backwards near the suture, then straight down, past the keel and
on the umbilical side forwards. The aperture is nearly circular, a little angular through
the outgoing keels. H. 2 mill., br. 7 mill. A single specimen has been found in the
limestone of Follingbo.

174 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Gen. CYCLONEMA Hac.
Cyclonema 1852. Hatt Pal. N. York vol. II, 89.

Shell turbinate, whorls ventricose, finely striated or carinated by longitudinal ridges,
which are more developed than the transverse ones, which often are wanting. The shell has
been nacreous, as can be seen by the traces left by the interior stratum on the nucleus.
The operculum is broadly conical, with some ten large coils outside, impressed by a shallow
groove along their superior border and streaked by oblique, transversal lines.

This genus comprises Litorina like shells, which differ from Oriostoma chiefly
through their operculum and through the regularly predominating, longitudinal orna-
mentation. In consequence of their characteristic operculum, which so much resem-
bles that of the Turbinide, they cannot any longer be regarded as Litorine as SroniczKa
has proposed.

In the strata of Gotland twelve species have been found and in the Lower Silu-
rian of Dalecarlia and of Oland there have been detected some well preserved speci-
mens of this genus.

1. Cyclonema delicatulum n.
Pl. XV figs. 27—44.

This shell, being one of the most common and characteristic of the Silurian for-
mation of Gotland, is, as may be seen by the many figures and by the dimensions be-
low, one of the most variable, with forms ranging between elongate Murchisonia like
shells to depressed globular ones like Natica. But the many transitional forms and
above all the characteristic ornamentation unite them. They are, moreover, found in
the same stratum and often on the same locality. The most common variety is figu-
red on plate XV fig. 28. It has four or five whorls, ventricose, with deep suture.
The body whorl is almost as long as all the others taken together. The ornamenta-
tion of the surface is a most delicate net work of fine, sharply elevated spiral lines
and equal sized transverse lines, which intercross them and at the meeting point form
a small blunt tubercle. The surface of each quadrangle, enclosed by these lines, is
with the aid of a magnifying lens seen to be minutely and transversally lineated. The
figures 42—44 on pl. XV, show how the form of these quadrangles varies in different
species according to the distance and position of the crossing lines, being elongate or
equal sided or transverse. Besides the now mentioned, prevalent type of the shell, there
are more elongated ones, of 6 or 7 whorls, the body whorl being equal to a third of
the whole length. The most extreme of the elongated ones is figured. In figures
40—41 the outlines of its antipodes are given, almost globular with enormously large
body whorl and short spire. The specimen figured on pl. XV fig. 45 is probably only
a corroded specimen of this form from the shale of Wisby.

The aperture is rounded, the exterior lip sharp and thin, entire, the inner one
thin, reflexed. There is no umbilicus. The common variety has in length 12 mill.,

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:o 6. 175

br. 10 mill. One of the extreme varieties is in length 14 mill., br. nearly 14 mill.,
height of aperture 10 mill. Another, the opposite extremity is 26 mill. in height and
it has probably, when the apex was entire, attained 30 mill. in height, br. of body
whorl 14 mill. height of aperture 11 mill.

This is one of the most abundant Silurian Gastropoda from the neighbourhood
of Wisby in the middle limestone (b) and also, though not so common, from the shale.
From the sandstone of Bursvik a small specimen has been obtained, which highly re-
sembles the Wisby specimens as to their ornamentation, but it is not certain that it
belongs here.

Cycl. delicatulum may. possibly be the shell designated by AnGexin in his Mu-
seum Palezontol. Suecicum as M# 49 Littorina? striata, but I have not succeeded to
find a complete series of that collection, containing this species with the others.

2. Cyclonema? apicatum n.
Pl. XVIII fig. 36.

Shell elongate, conical, whorls five, the body whorl more than double the size
of the others. They are moderately convex and the suture only slightly impressed.
On the body whorl there is a blunt angle, where the umbilical surface begins. It is
there the semblance as of a slit band, like that in the Pleurotomariz of the division
Multicarinati, but not sufficiently clear enough to decide if the shell really is a Pleu-
rotomaria. The surface is finely cancellated and the transverse strix are helow the
angle bent backwards. The band like sculpture is visible only on the body whorl.
The aperture is elongate, ovate, the lips are thin and sharp, and there is no trace at
all of any umbilicus.

The peculiar elongate, succinoid shape sufficiently distinguishes this shell from
similar. H. 7 mill., br. 5 mill.

This shell has been found in two specimens in the red limestone of Sandarfve hill.

3. Cyclonema cancellatum pn.
Pl. XVIII fig. 25—27.

Shell moderately large, turbinate, with seven ventricose whorls, of which the body
whorl is nearly twice as large as the spire. The surface is evenly rounded without any
prominent keels and it is regularly cross bared by thread fine, longitudinal lines and not
quite so prominent, transversal ones, covering the whole surface with minute quadran-
gles. Some of the longitudinal lines are at irregular distances rather more prominent.
The transverse lines have uniformly the same size and take in several specimens a
gentle curve backwards, run else straight and near the umbilicus directed forwards.
The aperture is obovate, the lips thin, the outer one in some specimens with a shal-
low, gently curved notch which also is clearly indicated by the above mentioned course
of the transverse striw. There is no umbilicus. H. 36 mill., br. 42 mill.

176 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Several specimens found in the limestone of the hills at Sandarfve and Linde.
Besides its size and shape this species is distinguished from the nearly allied C.
delicatulum through its ornamentation, which is different as to its direction and size.

4. Cyclonema distans n.
Pl. XVIII fig. 37.

Shell small, turriculate, of five whorls, of which the body whorl is nearly as
high as the spire. There are eighteen sharp, distinct, distantiated keels and the trans-
verse lines which intersect them are also distantiated but narrow. They are directed
slightly backwards, but converge on the umbilical side. H. 8 mill., br. 6 mill.

Only a single specimen has been found in the limestone of the hill of Sandarfve.

5. Cyclonema striatum His.
Pl. XVII fig. 48, pl. XVIII fig. 39—42.

Turbo striatus 1837. Husincer Anteckn. VI, 109, pl. VIII f. 2.
1837. Ip. Lethaa, 38, tab. XII fig. 5.
1840. Ip. Forteckn., 55.
1867. Linpstr. Nomina, 23.
Turbo Leda 1850. D’Ors. Prodr. IJ, 30.
Turbo striatus 1877. Kravusr Zeitschr. d. deutsch. Geol. Gesellsch., 23, can only with doubt be referred to
this genus.

Shell turbinate, with six ventricose whorls, suture deep and immersed; there are
only spiral, closely set lines, which vary in their distance from each other, but gene-
rally leave an interstice smaller than themselves. Around the umbilicus they are more
distant and more prominent. The last whorl is free near the aperture, which is quite
circular without any reflexed lips, which are sharp all around. The original specimen
of Histneer is figured here anew; it is fragmentary and the revolving lines are more
distant than in other specimens. In his collection there are two specimens thus de-
nominated, the smaller one is only a cast without shell from the shale of Hégklint. The
larger specimen, the figured one, is from Klinteberg and the Paleontological Museum
also has specimens from that locality as well as from Ostergarn, Samsugn in Othem
and the shale beds of Wisby. H. 16 mm., br. 14 mm., diam. of the aperture 6 mm. Turbo
corallii Sow., and Trochonema pauper Hatt 20:th Rep. p. 343, pl. 15 f. 5, 6 (= Cyclonema
pauper Hatt 20:th Rep., Docum. Ed. p. 395 pl. 15 f. 5, 6) come near to this shell.
The largest specimens somewhat resemble smaller specimens of Or. globosum or sculp-
tum. The narrowness or total want of any umbilicus, the elevated spire of rounded
whorls, the circular, nearly free aperture, however, distinguish them sufficiently.

From the limestone of Samsugn a specimen has been obtained with an oper-
culum in reversed position in its aperture. It has no doubt belonged to the shell,

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wn:o 6. 177

being of exactly the same size as the aperture. It is of quite the same shape as that
delineated on plate XVII fig. 48. It is depressedly conical, of about twelve coils and
perfectly circular outline. The coils are large, convex, with the superior border bent
out in a thin, laminar edge, the suture between them is shallow. The transverse, oblique
strie are distinct. The inside is deeply concave and in well preserved specimens
almost all the coils are seen, the outermost forming the elevated bordering rim.
Dimensions: diameter 6 millim., height 5 mill., thickness of margin 1 millim.

In the crystalline limestone near Westerby in Ardre there occur numerous nuclei,
which through some fragments of the shell with its sculpture make it evident that they
have been nearly allied with Cycl. striatum. There seems to have been some varia-
bility in the size and distance of the longitudinal, threadlike stria. The whorls are
six, tubular. Along with these shells, the only ones found there, lie a great number
of detached opercula of a type, quite corresponding to that of Cycl. striatum, though
modified in details. Its size also tallies with that of the shell. It is figured on plate
XXI fig. 66. It is of perfectly circular outline, moderately and obtusely conical.
Coils on the outside about twelve, large and broad, proportionately more so than in
Cycl. striatum. A little below the upper rim a shallow groove runs. The thin edges
of the coils are cloven by a narrow slit running along thei. The interspace between
the adjoining coils is very shallow. The outer sides are ornamented by densely crowded,
exceedingly fine and minute, oblique and transversal streaks, reminding of the somewhat
larger ones on the outside of the operculum of many of the recent Trochide and Tur-
ritellida. On the inside the centre is environed by a thick, callous whorl which en-
circles the innermost concavity. Around the whorl the surface is smooth and there is
no annular rim. This great dissimilarity of the interior surface indicates a different
specific type, which, however, can, for the present, not be succinctly enough described
as the shell is so imperfectly preserved. Dimensions of the shell: H. 23 mill., br. 18
mill. H. of operculum 5 mill., diameter 11 mill.

In connection with the forms of opercula, now described, two more may here
be mentioned, because they evidently belong to the same generic type.

1. Pl. XVII, fig. 50—52. From the lower strata of Ostergarn found in a few spe-
cimens. These resemble, as to their exterior, those from Ardre with their large, eight or
nine coils which also have a shallow groove running along their superior border. The
minute, transverse striz are not conspicuous and the top of the coils is more lacerated
by longitudinal slits. The inner side is also more excavated, fig. 50, and the central
whorl not so prominent. An annular rim is formed by the inside of the outermost
coil. H. 3 mill., diam. 8, thickness of the margin 1 mill.

2. Pl. XVII, fig. 49. This is acuminately conical, higher than broad, the base
is crushed, but it has probably had a circular outline. The coils are broad, band like,
ascending like steps, about fifteen. There are indistinct, oblique, transverse lines, nearly
parallel with the edges of the coils. A single specimen has been found in the upper-
most limestone of Lannaberg in Slite. Diameter 10 mill., height 17 mill. It has to
all appearance been still longer.

K. Sy. Vet. Akad. Hand]. Bd. 19. Nio 6. 23

178 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

6. Cyclonema zonatum n.
Pl. XVIII fig. 48—44.

Shell small, turbinate, with obtusely elevated spire of six whorls. These are
evenly rounded, the body whorl of the same size as the spire. The keels are longi-
tudinal, rounded, with interstices of equal size. The keel which is situated a little
below the median line of the body whorl is larger than the others and more distan-
tiated from the nearest and there thus originates a zone or a belt around the whorl.
Microscopically minute, transverse lines are crowded on the keels, deviating only slightly
from a vertical direction. Near the suture the longitudinal lines also are larger and
they leave a smooth zone between them and the suture. The aperture is obovate and
the umbilicus is narrow. H. 15 mm., br. 14 mill.

Four specimens derived from the red limestone of the hill of Sandarfve. There
is also from the same locality a very large specimen (h. 18 mm., br. 18 mm.) which
perhaps belongs to this species. The longitudinal keels, however, are, below the middle
of the whorl, not so distinct, nor is the zone so definite. A shorter variety with
larger strie has been obtained from the shale beds north of Skaret in Fréjel.

7. Cyclonema adstrictum n.
Pl. XV fig. 49.

Shell turbinate, of three whorls. The body whorl more than double the size
of all the others. It is nearly of elliptical outline, suddenly constricted in a more
narrow neck just above the suture; the next whorl is conically rounded without any
constriction. The surface is smooth and only through the magnifying lens a fine lon-
gitudinal striation is revealed, as of engraved lines, crossed by irregular short, arched
lines. The aperture is obovate with thin lips. There is no umbilicus. H. 15 mm.,
br. 16 mm.

Some specimens have been found in the red limestone of the hill of Sandarfve. This
is possibly identical with Naticopsis concinna Mac Coy Sil. Foss. Ireland p. 13, pl. I
fro.lO,

8. Cyclonema carinatum Sowersy.
Pl. XVIII fig. 28—30.

Turbo carinatus 1837. Sow. Sil. Syst., tab. 5 f. 28.
1843. Morris Catal, Brit. Foss. 165.
1848. Bronn Nomencl., 1358.
Turbo octavia 1850. D’Ors. Prodr. I, 30.
1854. Morris Brit. Foss., 283.
Litorina octavia 1855. Mac Coy Paleoz. Foss., 305.
Cyclonema octavia 1859. Sauter ap. Siluria ed. 3, 548, pl. 24 f. 4.
1873. Ip. Cat. Cambr. Foss., 156, 172, 185.

KONGL. SV. VET. AKAEMIENS HANDL. BAND. 19. wn:o 6. 179

Shell turbinate, acuminate, with six ventricose whorls, the five inferior whorls
with two sharp keels each. On the body whorl there are a variable number of 8 or
10 keels of which the lowest two are largest and most prominent, the most inferior
leaving a larger zone between itself and the suture than the space to the next keel.
There is also a low keel near the suture. The surface between the keels is finely and
transversally striated by dense, obliquely backwards slanting streaks. The aperture is
almost ovate, higher than broad and the umbilical opening is narrow, being in some
specimens covered by the inner lip, which is reflexed towards the columella. H. 30
millim., br. 25 mill., height of aperture 15 mill.

It has been found at Djupvik in Eksta, Samsugn in Othem, north of Skaret in
Fréjel and at Follingbo, Slite and Petesvik in Habblingbo.

8 a. Cyclonema carinatum Sow. var. glabrum n.

Shell small, turbinate, acuminate, five ventricose whorls with three or four lon-
gitudinal, distantiated keels on the apical side of the body whorl. They are entirely
wanting on the umbilical side which is almost smooth, only ornamented with the
same sort of faint, transverse stria as on the apical side. Around the umbilical cavity
a short, sharp ridge starts from the upper edge of the aperture, which is obovate,
acuminate below. The umbilicus is narrow. H. 8., br. 6 mill. It has been found toge-
ther with the typical specimens in the shale of Djupvik in Eksta.

8 b. Cyclonema carinatum Sow. var. multicarinatum n.
Pl, XVIII f. 31—32.

This differs chiefly from the main species through the numerous and small lon-
gitudinal keels, the nearly circular aperture and the large and open umbilicus. The
keels are as many as 14 on the body whorl and from five to seven on the whorls next
in size. On the body whorl the keels are more distantiated a little above the suture.
As many forms connect it with Cyclon. carinatum, forma typica, there is no cause to
represent it as a species of its own. H. 19 mill., br. 17 mill. Several specimens have
been obtained from the shale of Djupvik in Eksta.

9. Cyclonema nodulosum n.
Pl. XVIII fig. 33—35.

Shell variable with long or short spire, with deeply impressed suture, whorls six,
nearly disjointed, as seen by section fig. 35, with 8—10 distantiated keels. It differs
from Cycl. carinatum in the peculiarity that the transverse oblique strie at regular
distances are more elevated than the others, and where they cross the keels, they form
a small tubercle or nodule through which the surface acquires a retiform aspect. All
specimens have a wide umbilicus and the axis is hollow. The aperture is circular with
thin lips and almost free from connection with the next whorl. H. 20 mill., br. 16
mill. It has hitherto been found only in the shale of Djupvik in Eksta and Frdjel.

180 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

10. Cyclonema? tenuissimum n.
Pl. XVIIL fig. 38.

Shell globose with six whorls, the body whorl several times as large as the spire.
The ornamentation consists of narrow spiral lines, very fine and closely set, especially
on the umbilical side. The suture is partly filled up by the overlying whorls. The
aperture is transversally ovate and the lips thin. The umbilicus is deep and funnel
shaped. H. 10 mill., br. 11 mill.

There is only one specimen as yet found from the limestone of Follingbo.

11. Cyclonema? giganteum n.

There exist only some fragments of the nucleus, by which it can be concluded
that this shell was turbinate with much ventricose whorls, of which three are extant in
the same specimen. There are also impressions of fourteen moderately elevated longitu-
dinal keels, the interstices between which are finely and transversally striated. This
fossil which in its size so much surpasses the other Cyclonemata, as well as almost
all other Silurian shells, can only hesitatingly be referred to this genus with which it
else coincides as to the ornamentation of the surface. H. 86 mill., breadth of body
whorl 95 mill. It has been found in the shale beds near Wisby and in Lummelund.

12. Cyclonema perversum n.
Pl. XXI fig. 55—56.

Shell sinistral, to judge by the only existing fragment of three ventricose whorls,
elongated or turreted, ornamented by numerous thread like, somewhat irregular and
unequal, longitudinal striw. These are crossed, especially near the aperture by coarser,
elevated lines of growth and for the rest by narrow, impressed lines. The suture is
moderately deep, the aperture is elongate and angular, acuminate in its upper and in-
ferior corners and on the middle of the inner lip. The lips are thin and straight.
The umbilicus is visible as a narrow slit. Size of the fragment: height 16 millim., br.
12 mill.

The single specimen has been found in the upper gray limestone beds of the
hill of Linde.

Grn. TROCHONEMA Satrer.
1859 Satter Canad. Organ. Remains Dee. 1, 27.

Shell turbinate, elongated, keeled, with wide and open umbilicus, surrounded by an
elevated keel.

I have adopted this genus for a widely spread shell, which cannot aptly be uni-
ted with any of the previously known. Satter thinks that Inachus angulatus Hisrn-
GER (Oriostoma angulatum) probably is an extreme form of this group, but I cannot

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. wi:o 6. 181

find that there is any foundation for this supposition. Trochonema differs from Oriostoma
through its elongate spire and from Cyclonema in the sculpture and the wide and open
umbilicus.

1. Trochonema turritum n.
Pl. XXI fig. 15—19.

Shell elongated, turbinate, of seven whorls, angulated through the prominent
keels of which there are six on the body whorl, besides the sharply eminent one
around the umbilicus. The three lowest keels are sharper than those on the umbilical
side. The transverse lines of growth are thin, lamellar, with sharp edges, more or
less distantiated, the interstices varying in breadth from nearly two mill. to close con-
tiguity of the lamellew. On the keels they are bent in a little tubular fold. The in-
terstices are finely and minutely striated by lines parallel with the enclosing lamelle.
On the umbilical ridge the transverse lamelle are crowded and the strize converge in
the interior of the umbilicus. The aperture is obovate, the longitudinal axis being
the longest. Its outer lip is angular through the shallow notches, which cause the
longitudinal keels. The inner lip is straight and not reflexed. H. 37 mill., br. 29.

A great number of specimens has been found at Samsugn in Othem and also a
few in Martebo, in the limestone of Kyrkberget, Wisby, and on Galgberget near Wisby.
There is a more slender variety from Klinteberg, small, with the lamella more nu-
merous and crowded and the umbilicus narrow, reduced to a slit.

2. Trochonema muricatum n.
Pl. XVIII fig. 52—53.

Shell turriculate, acuminate, upper whorls rapidly increasing in size. Whorls six,
angular, body whorl with four large keels, the uppermost around the umbilicus. They
are lacerated with broad, acuminated points at regular distances all round. Each of
them is, as it were, a complex of the folded edges of several transverse lamellae, which
have a nearly straight direction. The aperture is elongate, angular through all the
keels in the outer lip. The inner lip is curved and thin. The umbilicus is wide and
open. H. 14 mill., br. 12 mill. A single specimen has been found in the middle li-
mestone strata of Hoburg.

In the list of the distribution of the species I had placed this shell in the ge-
nus Eunema Satter, but I now find, on closer consideration, that it cannot be kept
there, but rather corresponds with Trochonema.

Gen. CRASPEDOSTOMA gen. nov.’)

Shell globular, naticoid, commonly with transverse lamellar ribs. Aperture circular,
enclosed within an enormously enlarged and thickened border, formed by successive, thin
strata, in the superior, inner corner elongated in an acute spur and a smaller, corresponding
one in the inferior corner. The inner lip is bifurcated. The umbilicus is deep and narrow.

1 Kouonédor, collar, ocWua,. mouth, aperture.

182 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

This is a well characterized genus with its peculiarly framed lips and lamellar
ornaments of the shell. I have placed this genus with the Turbinide in consequence
of the congruence of its shell with several of the Liotide of which group there are
some representatives not only recent and tertiary, but also in secondary strata. What
Sroticzka says’). of Liotia is wholly applicable to the Gotlandic fossils in question.
He says: »The Liotide are usually of small size, sub-orbicular, with short spire, trans- —
versally and spirally ribbed, often umbilicated, with the aperture circular, having more
or less thickened and continuous margins». In the figure of Liotia Gervillei, given by
S. P. Woopwarp’), there is seen an acuminated spur projecting from the lower or
median edge of the inner lip quite as in ours. Strange enough no similar shells seem
to have been hitherto found in the Devonian and the Carboniferous Formations, as |
cannot find any mention made of such in the works of GoLpruss, SANDBERGER and
De Koninck.

D’Orsieny®) has described and figured a »Delphinula reflexilabrum», which comes
very near to our genus through its »bouche ronde, avec un bord fortement épaissi,
et réfléchi en un large péristome tranchant». It is derived from the Middle Lias of
France.

In the Upper Silurian of Gotland I have found six species and in the Lower
Silurian hitherto not a single one has been discovered.

1. Craspedostoma spinulosum n.
Pl. III fig. 32—34.

Shell globular, naticoid, last whorl several times as large as all the others. Whorls
four, of which three form the short spire. Suture shallow. The surface is richly or-
namented by transverse ribs, situated at regular distances and there provided with
blunt spines. These spines, being regularly distantiated, form rows which also conti-
nue on the reflexed outside of the lip and give its extreme edge a serrated outline.
The aperture is ovate, inferiorly somewhat more narrow. The outer lip with a broad
border forming an expansion at right angle to the outside of the last whorl, projec-
ting above it to the length of two millimetres. It is evident that there has been a
spur or processus on the interior, upper edge, and probably also beneath the inferior
corner of the aperture but both have been broken. It is imbricated by the wavy lines
of former lips, resting in their place, while the aperture has been more constricted.
The inner lip is straight, bifid, thin and smooth, but does not cover the narrow and
deep umbilicus. H. 14 millim., br. 15 millim., length of aperture outside the lip 18
millim., inside 7 millim.

From the limestone of Hoburg, between the oolite and crinoidal limestone strata,
where I found one specimen.

1) Paleont. Indica, Gasteropoda of the Cretac. Rocks, 351.
*) Manual of Shells, pl. 10 f. 14.
3) Paléont. Frang. Terr. jurassiques, 317, pl. 323 f. 14—16.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 183

2. Craspedostoma elegantulum n.
Pl. II fig. 58, pl. XXI fig. 20—29.

Shell globose, naticoid, whorls five, body whorl enormously developed, the others
forming a small, obtuse spire. The thin, transverse ribs are densely packed, running
obliquely, directed backwards toward the umbilicus. Their edges are minutely frilled
in a succession of diminutive wave lines and bent backwards, as to resemble hooks in
longitudinal sections. In older specimens, at least from some localities, the ribs are
distantiated, with smooth interstices near the aperture. Thread fine, longitudinal lines
cross them, especially distinct on the smaller whorls. They are usually more distan-
tiated than the transverse ones, though there also is variability and the longitudinal
strie are more close and numerous, pl. Il fig. 58. The aperture is obovate, rounded above,
pointed below, the outer lip is large and bent obliquely outwards, thin, and its inte-
rior corner, where it meets the inner lip, is prolonged in a triangular, acuminated
tooth which stretches far backwards and nearly reclines on the body whorl. The inner
lip is narrow, straight, near the umbilicus divided in two diverging branches through a
triangular slit between them. Of these the shorter one ends on the inner wall of the
umbilicus, while the longer borders the umbilicus on the outside. The umbilicus is
narrow and deep. H. 20 mill., br. 25 mill.

Several specimens have been found in the upper limestone strata of Slite,
Samsugn, Stor Wede in Follingbo, Nya Slitegards in Dalhem and Klinteberg.

3. Craspedostoma elegantulum var. brevispira n.
Pl. XXI fig. 30—34.

This variety is small, globular, with five whorls, spire short as not to be visible
when the shell is seen from the side. The aperture is large and widened. The supe-
rior spur is relatively shorter than in the former, more narrow and pointed. The or-
namentation of the surface is finer and more reticulate, the edges of the transverse
ribs only a little outstanding and obtuse. The umbilicus is wide and the two branches
of the interior lip widely diverging. H. 5 mill., br. 7 mill.

A few specimens have been found in the limestone of the hill of Sandarfve.

4. Craspedostoma filistriatum n.
Pl. XXI fig. 35—38.
Shell globular, helicoid, body whorl considerably enlarged, the spire prominent,

though obtuse, whorls four. The surface is smooth, nearly glossy, without any pecu-
liar ribs, of which there only are a few distantiated traces. The ornamentation con-

184 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

sists of minute and closely set transverse, nearly straight striz, crossed by more ir-
regular, wavy, impressed, longitudinal lines. The aperture is obovate, almost as in Cr.
elegantulum, but situated deep beneath the outgoing frame, which above is prolonged
in the characteristic spurlike process and below in an obtuse lappet. The interior
lip is bifid in the same manner as the others. On the outside of the body whorl near
the aperture there is a transverse, shallow groove dividing the enlarged apertural frame
from the deeply hidden aperture proper. This frame is here as in Craspedostoma ele-
gantuluin very thin und sharp edged. H. 10 mill., br. 13 mill.
Two specimens have been obtained from Klinteberg and one from Samsugn.

5. Craspedostoma involutum n.
Pl. XXI fig. 39—42.

Shell small, globose, helicoid, whorls five, spire short but prominent, the trans-
verse ribs numerous, close, with frilled edges where they meet the longitudinal strie,
which resemble those of the other species. The aperture is obovate, acuminate below,
the broad frame is broken away. The inner lip is bifid as in the others, its outer
branch straight and somewhat thickened, but its inner branch does not continue straight
down as in the others, it is convoluted around the central axis of the conical hollow
which it forms and thus hiding the umbilicus: h. 9 millim., br. 11 millim.

Four specimens have been found in the highest limestone stratum of Wisby on
Kyrkberget.

6. Craspedostoma glabrum n.
Pl. XXI fig. 43—54.

Shell globular, small, naticoid, thin, whorls five, with short, though prominent
spire and the body whorl many times surpassing the others in size. Surface apparently
smooth with only a few, much distantiated, transverse sigmoid ribs, which are faintly
prominent with an obtuse edge. Between them the surface is most distinctly longitu-
dinally striated by somewhat wavy and graduated lines and transversally to them and
parallel with the ribs there are microscopically minute lines. The aperture is circular
or obovate, environed by exceedingly broad, reflexed lips, forming a large frame around
it, of such enormous size that in relation to it the shell looks as an appendix. This
frame is prolonged in a large, acuminated spur near the umbilicus, which it nearly
completely covers and its lowest corner near the spire is also elongated in a triangu-
lar spur. The surface of the frame is finely lineated by the parallel, superimposed strata
of growth of successive lips, giving it an imbricated appearance. The umbilicus is
narrow. Only the largest specimens are provided with an inner branch of the inner
lip. H. 18 mill, br. 13 mill., breadth of aperture 11 mill.

Most abundant in the red and gray limestone of the hill of Sandarfve.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 185

Fam. XI PHORIDZ Gray.

Gen. AUTODETUS noy. gen.')
1884 Anticalyptrwa Quenstept Handbuch der Petrefaktenkunde, 3e Aufl., 673.

Shell broadly conical, sinistral, affied with the truncated apea to other marine bodies,
whorls externally not visible, no suture, aperture narrow, transverse, with a blunt, toothlike
projection near the centre of the flat, umbilical surface. There is no umbilicus, the axis is
solid. The shell is interiorly subdivided in bladderlike compartments along the exterior wall.

This curious little shell has by its first describers been referred to several recent
genera as Calyptreea, Capulus and Trochita, with none of which it, however, on closer
inspection can be regarded as related. This is chiefly found through the aspect of
the volutions in the interior, the characteristic sculpture of the umbilical surface and
its peculiar way of fixing itself with the apex to the hard structures of other animals.
In outward appearance it has certainly a great similarity to species of the recent genus
Galerus and also in some degree in the form of the aperture, which in some species of
Galerus have a tooth like prolongation. There seems, however, to be more reason to re-
gard it as a precursor of the recent Phoridw. The shape of the aperture as well as the
ornamentation of the umbilical surface justify this comparison. But instead of fixing
other objects to its shell, as its recent relatives, it fixed itself to larger objects.

This is, perhaps with exception of Clisospira, the oldest known representative of
this curious family, as there is before none older known than Xenophora or Pseudo-
phorus antiquus Merk*) and Phorus Bouchardi Euc. Destonescuamps®) both from the
Devonian formation. Then none is found before the Jurassic time. Perhaps also Tro-
chita antiqua? Merk") belongs to this family. But, as surmised above, it may be que-
stioned whether such Silurian shells as Trochus cavus, Tr. profundus etc. do not ra-
ther belong to the Phoride and to the genus Onustus.

Autodetus calyptratus Scurenk.
Pl. I fig. 17—24, pl. XXI fig. 57—60.

Capulus calyptratus 1854. Scurenk Uebersicht des Schichtensystems Liy- und Esthlands, 83.
1858. Fr. Scumrpt Geol. Hsthlands, 206, but not Patella mitreola Eicuw. Bull. Moscou
1854, I, 94.

Calyptrea calyptrata 1860. Ercuwatp Leth. rossica I,m, 1104, pl. 51 f. 13.
1867. QuernstepT Handbuch der Petrefaktenkunde 2e Aufl., 526, f. 117.

Trochita calyptrata 1867. Linpsrrom Nomina fossil. Gotl., 23.
Anticalyptrea calyptrata 1884. Quenstept Handb. d. Petref. 3:e Aufl., 673.

Shell irregularly conical, sinistral, with the truncated and affixed apex forming
a flat surface. A few large specimens from Lau and Hoburg seem to have freed
themselves at an early stage of growth and have a bluntly pointed apex, without.

1) *Avrodetog, who has bound himself.

2) Geol. Survey of Ohio, vol. I, 221.

3) Bull. Soc. Lin. de Normandie VI, 151.

#) Proceed. Ac. Nat. Sc. Philad. vol. 23, 82.

K. Vet. Akad. Handl. Band 19. N:o 6 24

186 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

any scar of the attachment. The whorls are in most specimens not apperceptible on
the outside, but through sections it has been made out that there with certainty are
six. They are almost smooth, not separated by any regular suture and are finely and
transversally striated by exceedingly narrow lines. These, which run in an oblique
direction, are crossed by more conspicuous, though minute lines and parallel with these
or with the umbilical border there are irregular ridges or constrictions or even edges
of the lines of growth. The affixed apex has often been strengthened by radiciform
offshoots, which give the shell a strange, nearly corallian aspect, and this is also the
case when two Autodeti have grown close together and, as it were, clasp each other
with their roots. In the youngest specimens the ornamentation, pl. XXI f. 58, is
better preserved and we see that the oblique, transverse lines are by far larger than
the delicate, longitudinal ones. The umbilical surface is much more distinctly circum-
scribed in this shell than in any other, excepting, perhaps, such forms of Trochi as T.
cavus and T. profundus. Its borders are very thin and seldom entire, but broken and
fragmentary. Inside the surface is moderately concave, elevated in the centre around
the axis in a faint convexity. Around this or as far as the thin margins reach, a
wreath of small bladders, of much unequal size in different specimens, as seen by figs.
18 and 22 pl. I, is stretching. These and the whole central surface are covered by
minute, wartlike prickles, amongst which curved striw radiate from the axis to the
periphery. There is no umbilicus and the axis is solid. The aperture is a narrow,
transverse slit with the upper lip laminar and ending in a blunt, broad, triangular
spine, which is bent a little upwards near the centre of the umbilical side. The inner
lip is thick and is distinctly separated from the surface. Around the inferior side of
the aperture the shell has, as in the recent Phoride, a covering of a thin, glossy stra-
tum of porcellaneous shell matter.

A longitudinal section, pl. I fig. 28, through the axis reveals five or six whorls
of elliptical shape and nearly similar to those seen in other regular shells and not at
all analogous to the spiral lamine in Calyptrea and Trochita. But there is a charac-
teristic feature in it, worthy of attention, and consisting in an accumulation of small
bladder like cells along the inferior corner near the wall of the whorls. These blad-
ders, in some cases amounting to as many as six above each other, are thus comprised
in an angle between the roof of a lower whorl and the floor of the next. They form
the circle along the inside of the umbilical border, described above, and may there be
seen in their original shape when uncovered. In pl. I fig. 19, rows of these bladders
are seen in a corroded specimen, indicating the wanting lines of the suture. These
bladders are then evidently formed on the top of the whorls along the thin rim of
the umbilical surface and are again covered during the growth of the shell by the
new whorls. By pl. I fig. 18 it can be found that they originate, as could be ex-
pected, near the outer corner of the upper apertural lip and thus had been formed
along with the aperture. As to the nature and homologies of these bladders, I can
for the present only compare them with the interior partitions through transverse la-
ming in several shells as in Triton corrugatus Lam.’). But there is the essential dif-

1) Woopwarp Manual of Shells, ed. 1, 100.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 187

ference that in this and similar (species of Conus ete.) the partitions are inside the
whorls and only near the apex, whilst in Autodetus they are decidedly outside the
whorls and everywhere along the suture.

The apical whorls are often filled with shelly matter and solid. H. of a speci-
men 6 mill., br. 8 mill. Another specimen from Lau, h. 5 mill., br. 9 mill.

The smallest or youngest specimens might easily be mistaken for young annelid
tubes. A few have been delineated on plate XXI figs. 57—60. Specimen, fig. 59—
60, is the youngest, nearly 2 millim. in diameter, broadly affixed, of nearly three whorls,
without the thin, umbilical border and with the centre of the axis prominent as a point.
Next we have, figs. 57—58, larger specimens, nearly 3 millim., where the thin border
just is beginning to appear. In this, as well as in the yet smaller, previous shell, the
ring of bladders is already present on the bottom of the aperture.

This characteristic shell is distributed nearly over the whole island and has been
met with in all strata, in the lowest shale beds, as well as in the uppermost limestone.
It is, however, more abundant in the southern localities. It has been found in the shale
beds of Halls huk, of Djupvik in Eksta and in the contemporaneous sandstone of Burs-
vik. The State Museum has further obtained it from the limestone beds at Medebys in
Hall, Likkershamn, Slite, Wisby, Ostergarn, Grétlingbo, Lau, from the oolite of Bursvik
and the middle and uppermost limestone of the hill of Sandarfve and Hoburg. It has
also been found in the isle of Oesel in corresponding strata, where ScuRENK first disco-
vered it.

Fam. XII. LITORINIDZ Gray.

Gen. HOLOPEA Hatz p. p.

21845 Cyclora Haut p. p. Sillim. Journ. vol. 48, 294.
1847 Holopea Ip. p. p. Pal. N. York vol. I, 169.
1866 Litiopsis Epw. Forsss according to Satrer in Mem. Geol. Survey, III, 346.
Shell globose, naticoid, with short spire, smooth whorls with faint, transverse striae,
outer lip thin, inner lip reflewed, peristome interrupted, umbilicus deficient or narrow.

According to the first definition given by Hatt these shells were difficult to dis-
tinguish from Cyclonema, as he states that the surface is cancellated. But in his la-
ter descriptions in Paleont. of N. York vol. III p. 294, species have been described
which are similar to the Gotlandic ones, enumerated below and also correspond with
those referred to Holopea by Satter in Mem. Geol. Survey vol. II p. 347, where also
species with high spire are included, which probably rather had to be numbered with
another genus.

1. Holopea nux n.
Pl. XV fig. 62.

Shell moderately large, ventricose, nearly globose, with short spire and body
whorl many times the size of the spire. Whorls five, obscurely and transversally stri-

188 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

ated. H. 17, br. 17. Fragment of a larger specimen 20 mill. broad. In the limestone
of Sandarfve kulle, Linde klint and from Samsugn.

2. Holopea transversa n.
Pl. XV fig. 59—60.

Shell minute, globose, with acuminate, though short spire, whorls five, ventricose,
smooth or glossy, body whorl transverse, aperture obovate, outer lip thin and sharp,
inner lip thick, reflexed and hiding the umbilicus. H. 7, br. 7,5 mill. Only a single
specimen found in Follingbo.

3. Holopea perforata n.
Pl. XVIII fig. 45.

Shell minute, globose, transverse, spire short and acute, whorls five, ventricose,
their surface smooth, only transversally wrinkled by a few, depressed lines of growth,
directed backwards or nearly vertical. Aperture obovate, or almost circular, both lips
thin, the inner one not reflexed. Umbilicus open, relatively wide. H. 12 mill., br.
13 mill. Two specimens from Kyrkberget in Wisby.

This species and the preceding one seem to form part of those shells which com-
pose the genus Cyclora of Hatt, but which well may be united with the Holopee.

4. Holopea nitidissima n.
Pl. XV fig. 50—51.

Shell minute, elongate, with five ventricose whorls, surface glossy, with faint
transverse striae. Suture slightly impressed. Aperture obovate, acuminated below, outer
lip thin, continuing on the body whorl without meeting the much shorter inner lip,
which is reflexed and hides the umbilicus. H. 8 mill., br. 6 mill. From Follingbo and
Kyrkberget in Wisby.

5. Holopea applanata n. .
Pl. XV fig. 46—47.

Shell elongate with five whorls of nearly conical outline, transversally and mi-
nutely striated, somewhat concave above the suture, which lies in a groove on the
inferior border of the whorls. Aperture obovate, outer lip thin, continuing on the
body whorl, without meeting the inner lip, which is thick and reflexed, hiding the
mbilicus. H. 10 mill., br. 7 mill. In all seven specimens from Kyrkberget in Wisby.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 189

Fam. XIII. SCALARIDA Broperip.

Gen. CALLONEMA Ha t.

1865 Isonema Merk and WorrHen p. p. Proceed. Ac. Nat. Se. Philad., 251.
1879 Callonema Hatu. Paleont. N. York vol. V,11, 50.

Shell elongate or short and globular, ornamented by transverse, distantiated lamellar
ribs, aperture circular, peristoma continuous.

This genus was established by Hatx to include some Devonian and Silurian spe-
cies which had to that time been numbered with Isonema, though they rather did not
correspond to the definition given to that genus by its authors Meek and WorTHEN.
I follow the subsequent authors who have placed the genus Callonema amongst the
Scalaride. In Sweden it had already appeared in the Lower Silurian times, as there
are fine species of it in the Leptena Limestone of Dalecarlia.

1. Callonema obesum pn.
Pl. XV fig. 27.

Shell thick, trochiform, of the same length and breadth, with transverse whorls,
broader than high, regularly increasing in size. Whorls five, ornamented with oblique,
chordlike, lamellar ribs, directed in a gentle curve, going from the suture backwards.
The surface acquires through them a fluted appearance, as these chords are more close
together than in the next species, finer and more regular. The aperture and the um-
bilical side are destroyed in the only specimen extant. H. 8 mill., br. 8 mill. This
specimen belongs to the Museum of the University of Copenhagen, and has been found
by AncELIN probably in the limestone of Wisby.

2. Callonema scalariforme n.
Pl. XV f. 24—26.

Shell elongate, turriculated and slender, of six moderately ventricose whorls.
Surface ornamented by obliquely transverse, thread like lamellew, and between them
with parallel lines of growth. The aperture is ovate and the lips thin. The lamelle
project beneath each other as scales, the younger beneath the older and they may pro-
perly be regarded as the edges of successive apertures. H. 15 mill., br. 10 mill. Ano-
ther specimen h. 10 mill., br. 5 mill., height of aperture 4 mill.

Some specimens from the middle limestone of Wisby.

Gen. HOLOPELLA Mac Coy.

Syn. 1852. Holopella Mac Coy Brit. Pal. Foss., 303.
1881. Aclisina De Kontncx p. p. Faune Carbonif. II, 3, p. 86.

Shell elongate, slender, smooth or finely striated, peristome continuous.

190 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

This genus should, according to Mac Coy be characterized through its remar-
kably convex whorls, which are ornamented by »slightly arched striz» or even cancel-
lated by transverse and spiral strie. Dr Koninck’s Aclisina then seems in no parti-
cular to differ from Holopella. The specimens are generally small. It has probably
occurred in the Lower Silurian of Sweden; at least Loxonema dalecarlicum Liypstrém*)
may rather be classed with Holopella and it is derived from the Leptawna Limestone
of Dalecarlia. In the Upper Silurian of Sweden there are three species, described be-
low. The genus has continued during the Devonian, the Carboniferous and probably
also during the Triassic times.

1. Holopella teres n.
PE XV fig Gl.

Shell elongate, thick, with seven whorls, which are smooth and transverse, twice as
wide as high, with glossy surface. Aperture circular, outer lip thin, the inner lip thick,
large and reflexed not only over the umbilicus, but also at the lower edge of the aper-
ture. H. 6 mill., br. 38 mill. Found in Slite.

2. Holopella regularis n.
Pl. XV fig. 12—13.

Shell moderately large, elongate, turriculate, with five ventricose whorls, separated
by a deep suture. The surface is smooth, glossy, covered by extremely fine, slightly
sigmoidally wound lines, the aperture ovate, below acuminate, with sharp and thin
lips. Umbilicus deficient. H. 21 mill., br. 10 mill. The aperture 8 mill. heigh, 6
mill. broad. The specimen figured belongs to Adjunct M. Krinrperc, who found it in
the shale beds of Wisby. It has also been found in the shale of Petesvik in Habblingbo.

8. Holopella minuta n.
Pl. XV f. 63.

Shell one of the tiniest found, being so uncommonly narrow in relation to the
length, regularly elongated and slender of eight globose whorls, one and a half time
as wide as high, regularly striated with fine, curved lines, having their greatest bend
along the median line of the shell. H. 7 mill, br. 2 mill. Occurs frequently in the
red limestone of Sandarfve kulle.

Fam. XIII. PYRAMIDELLIDZ Gray.
Gen. MACROCHILINA Baye.

1841 Macrocheilus PuiiLirs Paleoz. Foss. Cornw., 103.
1842 Plectostylus Conrap Proceed. Ac. N. Sc. Philad. 275.

!) AncELIN & LrnpstR6M, Fragmenta Silurica p. 14, pl. XV, f. 19.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. n:o 6. 191

1860 Soleniscus Mxrk and WortHEN p. p. Proc. Ac. N. Se. Philad., 467.
1879 Duncania Bayie Journ. de Conchyliologie, vol. 19, 35.
1880 Macrochilina Ip. ibid. vol. 20, 241.
Shell elongate, bulimoid, terete, aperture ovate, columellar lip considerably thickened
toward its base and twisted, often so much that an acute, revolving plait is formed.

I have ventured to place three species of Gotland Silurian shells within this
genus, mostly on acconut of their’general habitus. But this position seems also justi-
fied through the conformation of the inner lip, which, though not showing such a
distinct plait as in some of the Carboniferous species, is evidently tortuous as in many
of them and the Devonian ones.

The oldest authors placed these fossils with Buccinum as HornicHaus or Bucci-
nites ScutoTHEem, and of the subsequent names Soleniscus ought to have the priority,
as Macrocheilus as well as Plectostylus were already preoccupied. But as this genus
according to the revision of Wurrs’) contains chiefly species, which, whith their gutter-
like prolongation of the superior corner of the aperture, indicate relations with the large
division of the Siphonostoma, it can only partly be admitted as synonymic. Dunca-
nia, given by Bayi, had already twice been employed for corals, fossil and recent,
and its author consequently changed it into that now prevalent.

1. Macrochilina cancellata n.
Pl. XVIII fig. 46—47.

Shell elongate, bulimoid, terete, with seven much convex whorls, the body
whorl being nearly of the same length as the spire. The suture is rather impressed
in consequence of the globosity of the whorls. The surface is most finely ornamented
by minute striw, which intersect each other longitudinally and transversally, forming
small regular quadrangles. The aperture is elongated and ovate, the outer lip is thin,
the inner lip thick and slightly twisted in its central part. There is no umbilicus.
Height 30 mill., br. 19 mill. Eight specimens have been obtained from the hill of
Linde and two from Sandarfve.

2. Macrochilina bulimina n.
Pl. XV fig. 14—16, pl. XVIII fig. 48—49.

Shell elongate, bulimoid, whorls seven, moderately ventricose, body whorl in
length equal with the spire. Suture slightly impressed. Surface covered only with
rather irregular, transverse strie, finer and coarser intermingled. The aperture is elon-
gate, the outer lip sharp and thin, the interior one thickened towards the base, slightly
twisted and hiding the umbilicus. H. 17 millim., br. 10 millim. Another specimen,
h. 25 mill.,@br. 13 mill.

1) Proceed. Un. St. National Museum, vol. VI, 184.

192 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Several specimens have been found in the limestone of the hills of Sandarfve
and Linde.

This species comes very near to the Lower Silurian Holopea exserta Forsss,
Mem. Geol. Survey vol. III, p. 347, but is rather not so much ventricose.

3. Macrochilina fenestrata n.
Pl. XV fig. 17—18.

Shell elongate, slender, conical, with five whorls in the only, fragmentary spe-
cimen. ‘These whorls have a nearly conical outline and are very little convex, the suture
is shallow. The surface is almost smooth, reticulated by transverse and longitudinal,
impressed lines of extreme minuteness, forming regular, fenestrate quadrangles, relati-
vely more quadrate and larger than in M. cancellata. The aperture is elongate, acu-
minate and narrow below, widened and rounded above. ‘The outer lip is thin, the
inner one is thick and somewhat tortuous. H.12 millim., br. 5 millim.

A single specimen has been found in the limestone of Samsugn in Othem.

Fam. XIV. SUBULITID n.

Shell elongate, fusiform, aperture oblong, narrow, slightly, but most distinctly canali-
culated in the superior corner near the columella and thus a short siphon is formed. Whorls
generally straight, conical, smooth and unadorned and the suture very shallow.

In this family I enclose such paleozoic shells as Subulites and Euchrysalis. Bu-
limorpha Wuirrretp and Fusispira Hatt probably also belong here. What characteri-
zes them all, besides the elongate and smooth shells and the narrow aperture with in-
complete peristome, is the important feature of a distinct apertural canal, situated ex-
actly as in all Siphonostomata and quite as much developed as in several of them,
where it has attained its smallest dimensions. This will be found on comparing such
genera as Pisania, Metula, Mangelia and especially Daphnella with Subulites, as will
be done more in full further on.

We see, consequently, in this family the most ancient representatives of the great
section of the Siphonostomous shells. Hitherto the oldest known species of that
group have been found in the Triassic strata of St. Cassian in Austria. Shells bearing
affinity to Fusus and Fasciolaria, if not strictly belonging to these genera, but at all
events to the section of the Siphonostomata, have been described by Laupn*). The
limits of the range of the Siphonostomata in time must then be removed as far back as
to the youngest beds of the Lower Silurian, where there are species of Subulites found
in the Leptwna limestone of Sweden. In Esthonia species of Subulites have also been
discovered in the contemporaneous strata.

1) Fauna der Schichten von St. Cassian, III Gastrop. Denkschriften der Akad. der Wissensch. zu Wien,
Bd 28, 2e Abtheil., 31.

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wn:o 6. 193

The systematic place of the species of this family is by far not as easily cleared
up as their nature of siphonostomous shells and I think, that this question must for
the present be left undecided.

Gen. SUBULITES Conrap.

1842 Subulites Conrap Nat. Hist. of N. York, Geol. vol. II, 392, fig. 3.
1843 Polyphemopsis Portiock, Rept. Geol. of Londonderry, 415.

Shell slender, elongate and fusiform. Whorls straightly conical or only slightly con-
vex, suture shallow, and on both sides a nearly rectilinear outline is formed. Shell thin,
fragile and unadorned, last whorl elongated. Aperture elongate’ or more than double the
length against the breadth. It is narrow, the outer lip thin and its lowest corner prolon-
ged into a small acuminated hook, which is most characteristic. The inner lip is involute,
thus forming a central canal around the axis, and it ends above abruptly in a transverse
line, from which the apertural edge continues in a rounded arch. They have a tendency
to grow obliquely along a curved axis.

On plate XVIII a sketch of the aperture of the recent, siphonostomous Daphnella
limnziformis L. has been given, fig. 64, to compare with that of Subulites ventricosus,
figs. 58 & 59, and of Subul. curvus fig. 61. The great accordance, especially between
fig. 64 and fig. 59, is striking. In all there is almost the same form of the aperture, on
the columellar side the same narrow coating of a thin porcellanons stratum, and, above
all, uppermost the peculiar and characteristic notch which indicates where the sipho
is protruded in the recent shells and probably also had been protruded in the extinct
ones. As far as this evidence goes, there is every reason to conclude that Subulites,
as well as the related genera, also have been siphonostomous. The transverse sections
of Subulites and Euchrysalis, figs. 62 & 68, show the inflected columellar lip in the
same manner as a similar section of Daphnella, fig. 63, while the section of a holosto-
mous, recent Turritella, fig. 69, is quite different.

The oldest specimens of this genus already occur in the Leptena Limestone of
Dalecarlia. In the »Fragmenta Silurica»*) I have with some hesitation described a
species as Subulites elongatus Porrtock, but I now think that it is identical with Heli-
cites utricularis WAHLENBERG”) and that it thence is to be named Sub. utricularis. This
genus seems to be restricted exclusively to the Silurian formation.

1. Subulites ventricosus Ha tt.
Pl. XV fig. 19—21, tab. XVIII fig. 58—AS9.

Subulites ventricosa 1852. Hat Pal. N. York, Il, 347, pl. 85 f. 7.
1865. Ip. 20th Rept. N. Y. St. Cab., 346, pl. 15 f. 1.

1) Pac. 3, pl. XV f 21—23.
*) Petref. Suec. p. 72.

K. Sv. Vet, Akad. Hand]. Bd. 19. N:o 6 25

194 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Subulites brevis 1865. WuincHett and Marcy, Fossils of the Niagara Limestone of Chicago in Mem.
Boston N. H. Soc., vol. I, 100, pl. IL f. 19.
1868. Meek and WortHen Geol. Survey of Illinois, III, 362, pl. 5 f. 6.
Subulites ventricosus 1868. Hari 20th Rept. N. Y. St. Cab. Revis. Ed., 398 pl. 15 f. 1.

Shell, short, thick, with five whorls, body whorl in length equal to the other
four whorls, with which it forms a small angle. Seen from the side the axis is slightly
curved. The aperture is narrow, elongate, inferiorly acuminate, above rounded; lower
lip continued downwards in an acuminated point. The outer lip thin and sharp,
somewhat inflexed, inner lip involuted, bent in a gentle curve and covered with a thin
coat of porcellanous shell matter. The siphonal notch is small, but distinct and di-
rected obliquely towards the outer lip. H. 388 mm., breadth 20 mm., h. of aperture
19 mm., breadth 10 mm. There is commonly only the nucleus left and the few ve-
stiges of the shell and its ornamentation show a smooth surface. Through the exte-
rior resemblance with American specimens, which I owe to the kindness of Messrs S.
A. Mitter and Worrnen, I have thought it most convenient to refer the Swedish spe-
cimens to the same species as the American ones.

It occurs in the soft shale at Hallshuk north and south of Wisby, Gnisvard,
Walve ref, Westergarn, also from Faré and the canal in Rute. Prof. Creve found

specimens in Haftingsklint.

2. Subulites ventricosus, var. curvus pn.

Pl. XVIII, fig. 60—61.

Shell slender, bent in a crescent shaped curve, the body whorl forming with the
apical ones a larger angle than in the preceding. Whorls six, elongated, slightly con-
vex, smooth, the suture shallow. The aperture is narrow and nearly elliptical, acumi-
nated below and widened above, where the sipho is situated. The inferior corner of
the outer lip is widened in a downwards directed thorn. H. 33 millim., br. 15 millim.
This variety which I consider as an evolutional form or mutation of the preceding,
has been found only in the upper limestone beds near Wisby at Kalens Qvarn and
Kyrkberget and in the limestone of Samsugn.

It differs from Sub. ventricosus chiefly in the more slender shape which is so

much curved.

3. Subulites attenuatus n.
Pl. XV fig. 22, 23, 48, pl. XVIII fig. 62.

Shell elongate, slender, fusiform, with seven whorls, body whorl nearly twice as
long as broad, axis of the shell straight, not curved. Surface of the extremely thin
shell smooth, without the least traces of ornamentation preserved on the patches still
left. Aperture elongate, narrow, nearly four times as long as broad. Lips thin, lower
corner of outer lip prolonged in a little acuminated thorn. Aperture on columellar

KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. wn:o 6. 195

side gently curved, lip much involute. H. 60 millim., br. 19 mill., length of body
whorl 35 mill., width of same 6 mill., length of aperture 29 mill., width of same 8
illim.

Abundant at Lansa and other places in Faré, at Wialmsudd in Bunge, in the
canal from Stormyr in Rute, in Martebo, in the shale beds of Wisby, Westergarn and
Gnisvard.

The specimen delineated on plate XV fig. 48 deviates thus far, that it is more
slender and the whorls relatively much longer than wide, but as there is only one
specimen as yet found, I cannot ascertain if it is a distinct variety or species.

Gen. EUCHRYSALIS Lause.

Buchrysalis 1868. LauBeE Denkschriften der Akad. der Wissensch. in Wien 2e Abtheil., 69.

Shell elongate, widest at the middle of its length, whorls short and numerous, smootl:
and glossy, suture shallow, the aperture long, narrow, outer lip sharp and thin, the mner
lip involute as in Daphnella, ending upwards in a very shallow notch.

After having compared specimens of Euchrysalis fusiformis Minster from St.
Cassian with specimens from Gotland described below, I cannot but think that they
all belong to the same genus. The Silurian species deviates, however, from the Tri-
assic ones in having a fine sculpture on the glossy surface. The characteristic fori
of the aperture and the general shape of the shell itself is quite identical. No species
seem hitherto to have been found in the Devonian and Carboniferous formations.

Euchrysalis lineolata n.
Pl. XVIII fig. 65—68.

Shell conical, tapering, slender, acuminated and straightly grown, with nine whorls,
regularly increasing in size, the body whorl being only twice as large as the next pre-
ceding. The whorls are only slightly convex or tumid around their middle and the
suture is not much impressed. The surface is sculptured by perpendicular, equidistant,
minute ridges, which have their inner side thrice as large as the exterior one. For
the rest the surface is smooth. The aperture is, as far as visible, elongated and poin-
ted below, widened above. The columellar lip is involute and the siphonal notch,
above, only just perceptible. H. 13 millim., br. 4 mill. Another specimen: h. 18 mill.,
br. 4 mill.

A dozen specimens have been found in the beds of the red and gray limestone
of the hills Sandarfve and Linde.

196 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Additional genus, the systematic place of which is at present uncertain.

Gen. ONYCHOCHILUS n.*)

Shell ovate, sinistral, aperture narrow as a slit, oblique, outer lip with thick border,
the inner lip involute, elongate and curved like a claw, probably with a rudimentary si-
phonal notch. The umbilical region is excavated and deepened into a funnel, wide above
and narrow downwards.

This genus must remain provisional untill more specimens have been collected,
apt to further elucidate its structure and systematic place.

1. Onychochilus physa n.

P]. XV fig. 55—58.

Shell tumid, ovate, sinistral, whorls four, the last being of more than double the
size of all the others taken together. The surface is transversally striated, parallel
with the outer lip, the strie fine, like ribs, running nearly straight from the suture to
the umbilicus. The aperture is obliquely elliptical, the outer lip thick, turned out in
a narrow elevated rim, the inner one involute and the whole side narrow. The um-
bilical region is partly destroyed and partly covered as not to be discernible. H. 4
millim., br. 3 millim. Another specimen is 8 millim. in height.

Two specimens, found in the uppermost limestone of Slite by Prof. P. T. Creve,
are preserved in the Museum of the University of Upsala.

2. Onychochilus reticulatum n.
Pl. XXI fig. 61—65.

Shell small, trochoid, obese, whorls four, tumid, body whorl more than twice
surpassing the other whorls. Their sides are straight or even, only slightly convex
and the suture is shallow. The ornamentation consists of fine, longitudinal striz cros-
sed by thicker, transverse, elevated ridges, nearly double as large and running obli-
quely from the suture backwards to the umbilicus. There are small, indistinct tuber-
cles at their meeting. The aperture is oblique and narrow, a little more widened at
its superior edge. Both lips are thin and the inner one shows the peculiar, clawlike
curvature. The umbilicus is a funnel, wide upwards and narrowing downwards. Sectio-
ned longitudinally the whorls show an elongated kidney like shape, being somewhat
impressed on the inner side, turned against the umbilical funnel. H. 4 millim., br. 3

mnillim. Three specimens have been obtained from the red limestone of the hill of
Sandarfve.

1) “Ovvs, claw, zeidog lip.

KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. -n:o 6. 197

3. Onychochilus? cochleatum n.

Pl. XVIII fig. 54—57.

Shell small, narrow, sinistral, elongately turriculate. The fragmentary specimens
have only five whorls left. These whorls are short, depressed, nearly disciform, with
? ’
an acute ridge around their median line and another ridge on the umbilical side.
Transverse lines, regularly distantiated, cross these ridges in a highly acute angle. To
>] oD ? oO o y {2}
judge by the fragments the columellar side of the aperture has been narrow and cur-

ved and the umbilicus open and wide. H. 6 mill., br. 4 mill.
From the limestone beds of Slite and Sandarfve.

198

G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

APPENDIX A.

Table showing the succession of the Paleozoic strata of Sweden.

Ih

OW bo

1. Cambrian.

Oldest sandstone beds of Westrogothia etc. Eophyton and Fucoid sandstones
at Luenas.
Paradoaides-schists.
a) Zone of Paradoxides Kjerulji. Hyolithus. A »Metoptoma» found by Scama-
LENSEE according to Lysy.
) Parad. Ocvlandicus.
) Parad. Tessini. »Metoptoma» Barrandei Lysy.
) Parad. Davidis.
) Parad. Forchhammeri.
f) Agnostus levigatus.
Olenus-schists.
Dictyonema-schists.

' Il. Lower Silurian.
Ceratopyge-limestone.
Lower Graptolite-schists.
Orthoceratite-limestone.
a) Lower red limestone. Pleurotomaria.
b) Lower gray limestoné. Bellerophon. Euomphalus
c) Upper red limestone. Metoptoma.
d) Upper gray limestone. Conularia.
Middle Graptolite-schists.
Chasmops-limestone. Conularia. Tremanotus.
Ti inucleus-schists. Phanerotinus (?).
Brachiopod-schists. Platyceras.
Upper Graptolite-schists (Retiolites shale of Borenshult ete.) Conularia. »Patellay
antiquissima. Murchisonia.

Leptena-limestone of Dalecarlia. Platyceras. Cyclonema. Callonema. Holopella. Subulites.

Ul. Upper Silurian.

Llandovery-beds near Wisby in Gotland, also at Stygfors and Nitsjé etc. in
Dalecarlia.

Wenlock shale and sandstone of Gotland. Signed a, see page 7.

Limestone beds of Gotland, Scania and Jemtland, shale and sandstone beds
of Scania. The Gotland beds are signed 6 and ¢ on pages 7 & 9 and
following.

KONGL. SV. VET.

AKADEMIENS HANDL. BAND.

19. N:0 6. 199

APPENDIX B.

Index to the generic names applied to the Gastropoda of the
Paleeozoic Period.

Aclis Loven 1846, Ind. Moll. 16, used by
White 1881, App. to Rep. U.S. Geol.

Survey vol. III, xxxv, for a Carbonif. |

shell.

Aclisina De Koninck 1881, Faune du Cal- |
caire Carbonif. de la Belgique I,m, |

86. Like a Holopella.

Acroculia see the next.

Acrocylia Patties 1841, Paleozoic. Foss. of
Cornwall, 93. As the name is deri-
ved from @xgoyv apex and #vd@ I roll,
it must be written as here. Identic
with Platyceras, which is prior.

Acrocyllia HERMANNSEN 1846, Indicis Gen.
Malac. primordia, 15. See Acrocylia.

Actita Fischer von WaLpHEIM 1823, Mém.
de la Soc. imp. d. Naturalistes de Mos-
cou vol. VI, 234. Deriv. extitye, living
near the shore. Intended not only for
the recent genera Capulus and Pile-
opsis, but, as seen in Bull. de Moscou
1844, 832, FiscHer also included Car-
boniferous Platycerata in it.

Agnesia De Kon. 1883, Faune Carb. Belg.
Il,ur, 99. A sinistral Pleurotomaria.

Ampullacera Quoy & Gamarpd 1832, Voy.
Astro]. Zool. II, 196. Used by De
Kontnck 1843 in Anim. Foss. Carbonif.
Belg. 486. One of the Pleurotomaridee
= Scalites according to Dr Kon. 1881.

Ampullaria Lamx 1799, Prodr. 76, employed
by Sowersy 1825, Min. Conch. VI, 40,
for shells of the Belgian Carbon. Form.
probably Euomphali.

Anatomus Montrorr 1810, Conch. Syst. Il,
278. = Pleurotomaria p. p.

Anomphalus Merk & WortHEN 1866, Pro-
ceed. Acad. N. Se. Philadelphia, 268.
Seems to be one of the Umbonide.

Anthracochiton RocHepruNne 1882, Ann. Se.
Géol., XIV, 26. Carbonif.

Anticalyptrea QuEnstepT 1884, Handbuch
der Petrefaktenkunde, 3e Aufl., 673.
Autodetus.

Autodetus Lixpstr6m 1884, Silurian Gastro-
poda of Gotland, 185. One of the

Phoride.

Baylea De Kon. 1883, Faune II,1v, 68, Fam.
Pleurotomaride ?

Bellerophon Montr. 1808, Conch. System.
Pole

Bellerophus BuatNvitte 1825, Malac. 477.
»Mala emendatio» of the preceding,
says HErRMANNSEN.

Beloplazus Orntert 1381, Mem. Soc. Geol.
de France, 3 Ser. vol. II, 17. A Devo-
nian Chitonid; type Chiton sagittalis
SANDBERGER.

Bifrontia DzesHayEs 1833, Descript. Coq.
Foss. des environs de Paris II, 221.
Contains chiefly Tertiary species, but
DesHayeEs also ranged Euomph. catil-
lus in this genus.

Brilonella Kayser 1873, Zeitschrift Deutsch.
Geol. Gesellsch., 672. A Devonian shell
of the Pleurotomaride.

Bucanella Meex 1870, Proceed. Amer. Phi-
los. Soc, vol. 11, 426.

900 G.

Bucania Hatt 1847, Pal. N. York I, 32.
A Bellerophon with cancellated orna-
mentation.

Buccinites SCHLOTHEIM
kunde, 127.
Devonian Macrochiline.

Buccinum L. 1758, S. N. ed. X, 734. Hornic-
HAUS and others used it for species of

1820, Petrefacten-
Contains, besides others,

Macrochilina.
Bulimella Hari 1858, Transact. Albany In-

stit. vol. IV, 29. = Macrochilina? The |

name is preoccupied by PFrerrreR in
1852.

Bulimorpha Wuitrietp 1882, Bullet. J 3, |

American Museum Nat. Hist., 74.

Callonema Hatt 1879, Pal. N. York vol. V,
pt. II, 50. The species of this genus
were formerly regarded as belonging
to Isonema.

Calyptrea Lam. 1799, Prodr., 78. Autode-
tus was first considered to belong to
this genus by Ercuwatp Leth. ross. I,
pt. 2, 1104.

Capreolus R. Eruermer Sr 1878, Qu. Journ.
Geol. Soc. vol. 34, 603, lapsu pro Ca-
pulus.

Capulus Montrorr 1810, Conch. System.
Il, 54 has been applied by various
authors to most species of Platyceras.

Carinaropsis Hatt 1847, Pal. N. York, I,
183. Species of Bellerophon and Le-
petopsis.

Catantostoma SANDBERGER 1842, Lronn. &
Bronn Jahrb. 392. Fam. Pleurotoma-
ride.

Centrifugus Histncer 1835 in a letter to
Bronn according to Lethea Geogn.
vol. 1 ed. 1, 96. = Inachus His:

Cerithium ADANSON 1757, Seneg. 153. Used
by VerneuiL and others for Silurian
shells of different genera.

Chelodes Davipson & Kine 1874, Qu. Journ.
Geol. Soc., 167, a subgenus of Chiton.

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Chemnitzia D’Ors. 1839 in Wess and Ber-
THELOT Iles Canar.... HEeERMANNSEN.
Ind. I, 222 identifies Loxonema Puit-
tips and Phasianella p. p. Goupr. with
this genus.

Chiton L. 1758, S. N. X, 667. BarranpeE
Syst. Sil. Boh. Ill, 175 has a species
of Chiton, which belongs to Chelodes.

Chonechiton CARPENTER 1882 according to
Datt Proceed. Un. States Nat. Mu-
seum, 1882, 280. Carbonif. Belgium.

Cirridius Dn Kon. 1882, Faune, I,m, 101
= Cirrus Dre Kon. 1843 not Sow.

Cirrus SowERBY 1816, Min. Conch. I, 93 =
Euomphalus according to Sowrrsy him-
self 1 ‘ci page:

Clisospira Brnurncs 1865, Pal. Foss. I, 186.
A Lower Silurian species probably al-
lied to Autodetus or the Phoride.

Codonochilus (not Codonocheilus) Wurr-
EAVES 1884, Geol. Surv. of Canada, Pa-
leoz. Foss. vol. HI pt. I, 17. Upper
Silurian Canada.

Coelocentrus ZivTEL 1882, Handbuch d. Pal.
1 Bd., 206 = Cirrus De Kon. Euomph.
Goldfussi D’Arcu. & VurN is the type.

Conchopeltis Watcorr 1876, 28th Rept. State
Cab: Ni. Ys..938. .A.Patellordsor a
Pteropod?

Conchula STHININGER 1855, Geognost. Be-
schreibung der Eifel, 46. Differs from
Scoliostoma through the shape of the
aperture, which is parallel with the
axis of the shell. Devonian.

Craspedostoma Liypstr. 1884, Silur. Gastro-
poda of Gotland, 181.

Cryptenia E. Destonccuamps 1865, Bull.
Soc. Linnéenne de Normandie, 424. A
Pleurotomaria found in the Carbonife-
rous strata and also in Lias.

Cyclonema Hauu 1852, Pal. N. Y. vol. I, 89.

Cyclora Hart 1845, Sillim. Journal, vol.
48, 294.

e
- Da

KONGL. SV. VET. AKADEMIENS HANDL.

Cyrtolites Conrad 1838, Ann. Rep. N. Y.
State Cab., 118.

Cyrtonella Haut 1879, Pal. N. Y. vol. V, pt.
II...1.28;

Delphinula Lam« 1804, Ann. du Muséum IV,
108. Gotpruss and Hisincer have re-
ferred several of the Oriostomata to
this genus. True Delphinula begin to
appear in the strata of St. Cassian.

Dentalium L. 1758, S. N. ed. X, 785. The
oldest species known are Devonian.

Ditaxopus Rarresqur 1839, Bull. Soc. Geol.
X, 878. Perhaps a Bellerophon.

Duncania Bayiy 1879, Journ. de Conchy-
hiologie vol. 19, 35, later changed into
Macrochilina.

Eecyliomphalus (not Ecculiomphalus) Porr-
Lock 1843, Rep., 411. Most species
nothing but evolute Euomphali. Ac-
cording to the derivation the name is
to be written as above.

Elenchus Humpenrey 1797, Mus. Calonnia-
num..., according to Mac Coy Carb.
Foss. Ireland, 42, a species in the Old
Red Sandstone of Ireland, but may
probably belong to another genus.

Ellipsolithes Sowrersy 1813, Min. Conch.,
vol. I 81, non Montrort, whose genus
embraced only Polythalamia. Sowersy
has himself later in Min. Conch. vol.
5 p. 107 corrected his species and in-
dicated two as Cephalopoda and one,
Eu. ovatus, as a Bellerophon.

Entalis Gray 1840, Syn. Brit. Mus.... See
Waacen. Pal. Ind. XII p. 180.

Hotrochus Wurrrietp 1882, Bullet. Amer.
Mus. N. Hist. # 3 p. 77.

Huchrysalis Lause 1868, Denkschriften Akad.
Wissensch. zu Wien, 2:e Abtheil. 69.
Silurian and Trias.

Eulima Risso 1826, Hist. 1V p. 123, Loxo-
nema and Polyphemopsis are synony-

mous according to HeRMANNSEN.

K. Sv. Vet.-Akad. Handl. Bd. 19. Nzo 6.

BAND. 19. N:0 6. 201

Eunema Saurer 1873, Catal. Mus. Cambrid-
ge, 156.

Kuomphalopterus Frerp. Roemer 1876, Leth.
Geogn. Atlas. Taf. 14. f. 9. — Type,
E. (Pleurotomaria) alata, Silurian.

Euomphalus Sow. 1814, Min. Conch. vol. 1, 97.

Euphemus Mac Coy, 1844 Carbonif. Foss.
of Ireland, 25. Although M’Coy him-
self later, in Brit. Paleeoz. Foss., 308,
declared that this genus was identical
with Bellerophon, the slit band having
by oversight been described as defi-
cient, WaAaGEN and Deg Konrycx have
again tried to revive it. But on com-
paring the species described by both
these authors as belonging to Euphe-
mus, it is easily found that the Eu-
phemus of WaaGrn cannot be recon-
ciled with that of Dre Kontncx. While
the latter author as Euphemi describes
K. Urii and other Bellerophons, Waa-
GEN makes us acquainted with several
forms so strange, that it may be doub-
ted whether they are Gastropoda at
all or not rather Cephalopoda of some
new genus.

Exogyroceras Merk and WorrTHEN 1868, Geol.
Survey of I[linois, vol. III, 509.

Fissurella Brug. 1789, Eneyel. method. vol. I
p- XIV, paleozoic according to GoLp-
russ and Mac Coy, but Juertme, Moll.
p. 78, says that they are met with
first in Trias.

Flemingia Dn Kon. 1882, Faune II, im, 94.

Fusispira Hau 1870, 24th Rep. St. Museum
N.pMorkyp.4229t

Glyptobasis Dr Kon.. 1883, Faune, I, m1, 92.
Similar to a Trochus.

Glyptochiton Dw Kon. 1883, Faune I, m,
Die

Gosseletia Dp Kon. 1883, Faune II, m, 28.
The name is already in 1881 preoc-

26

202

cupied for a Lamellibranchiate by Cu.
Barros in Ann. Soc. Géol. du Nord
VIII p. 176. Pleurotomaria.

Gryphochiton Gray, 1847, Proc. Zool. Soc.
p. 70. Devon. and Carbon.

Gyrotrema Barranpe 1868, apud Biassy.
Thes. Silur. p. 167 = Tremanotus.
Hatt.

Helcion Montrorr 1810, Conch. Syst. II p.
63, applied by some to paleozoic Pa-
tellids.

Helicites ScutoruEtm 1813, Jahrb. VII p. 35.
Contains species of different genera,
as Euomphalus, Pleurotomaria, Orio-
stoma.

Helicotoma Satrer 1859. Dec. I, Geol.
Survey of Canada, 10 = Euomphalus
and Pleurotomaria.

Helminthochiton Saurer 1846, Proc. Geol.
Soc Lond, 49, Si, 2) £.-6-

Hercynella Kayser 1878, Fauna der alte-
sten Devonabl. d. Harz, 101. = Pili-
dium Barr. Mss not Fores.

Holopea Hatt 1847, Pal. N. Y. vol. I, 169.

Holopella Mac Coy 1852, Brit. Pal. Foss., 303.

Hormotoma Saurer 1859, Canad. Organ.
Remains Dec. I, 18. = Murchisonia.

Tgoceras Watt 1859,. Pal N. Y. vol IU,
330. = Platyceras.

Inachus Histncer 1888, Lethea, 37. Name
preoccupied for a Crustacean. Consi-
sted of three species of which one, I.
sulcatus, is a Pleurotomaria, I. angu-
latus, is a Oriostoma and I. costatus a
Cephalopodous shell, probably a Tro-
choceras.

Isonema Merk and Wortuen 1865, Proce.
Acad. Nat. Se. Philad., 251.

Lepetopsis Wurrrietp 1882, Bullet. Amer.
Museum of Natural. Hist. 4% 3, 67.

Litiopsis Epw. Forses accord. to SALTER
1866 in Mem. Geol. Survey III, 346 =
Holopea.

G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Litorina Frr. 1821, Tabl. System., XXXIV.
Several of the palewozoic species, which
have been called Cyclonema, were re-
garded as Litorine by PrcTer.

Loricites CARPENTER accord. to Dati, Pro-

U. S. Nat. Mus. 1882, 281, A

Carboniferous Chitonid from Belgium.
1841, Paleoz. Foss. of

ceed.

Loxonema Putt.
Cornwall, 98.

Luciella Dn Kon. 1883, Faune Carbonif.
Belgique U,1v, 107. A Pleurotomaria.

Maclurea Emmons 1848, Geol. N. Y. I,
ol.

Maclurita BuaINnviILLE 1825, Malac., 424.

Maclurites Le Sueur 1818, Journ. Ac. N.
S. AVOlamnette,

Macrochilus (not Macrocheilus) Pun. 1841,
Palwoz. Foss., 103.

Macrochilina Baye 1880, Journ. de Con-
chyliologie 3 Ser. vol. XX, 241. = Ma-
crochilus & Duncania.

Margarita Leacu 1819, Journ. de Phys.
464, Waacen Salt Range Fossils, 111.

Metoptoma Puttu. 1836, Geol. Yorkshire pt.
2, 223.

Michelia F. A. Rormer 1854, Paleontogra-
phica Bd. 3, 73. Near Loxonema.
Microceras Hatui 1845, Sillim. Journ. vol.

48, 294.

Microdoma Mrex and WorrTHEN 1866, Phi-
ladelphia Proceed. 269.

Mitchellia De Kon. 1876, Foss. du Nouv.
Galles du Sud I, 128.

Mogulia Waacrn 1880, Salt Range Foss,
Paleont. Indica vol. XIII, 131.

Mourlonia Dr Kon. 1883, Faune Carbonif.
de Belg., 245. = A Pleurotomaria.

Murchisonia D’Arcutac & VerneuiL 1841.
Bull. Soc. Géol. XII, 154.

Narica Ricruz 1841, according to D’Ors.
Moll. Cub. I, 389, used by De Koninck
1844, Anim. Terr. Carbonif., 475.

KONGL. SV. VET. AKADEMIENS HANDL.

Nassacites Krieger 1823, Gesch. der Urwelt
Th. 2, 417. = Machrochilina?

Natica Apanson 1757, Sénégal., 172. D’Or-
picNy and Picrrr consider that this
genus is represented in the Silurian
formation, probably = Platyceras.

Naticella Swainson 1840, Malac., 345. There
are species referred to this genus de-
scribed from the Silurian and Carbo-
niferous formations, but probably be-
longing to other genera.

Naticodon De Rycxnorr 1852, Mélanges
paléontologiques, 75, in Mém. Cour.
Acad. R. d. Sci. de Belgique Ire pt.,
75. Carboniferous.

Naticopsis Mac Coy 1844 Synops. Carbo-
nif. Spec. of Ireland, 33.

Natiria De Kon. 1881, Faune Cale. Carbo-
nif. Belg. II, im, 5.

Nerita L. 1758 S. N. ed. X, 776, N. hali-
otis Sow. Sil. Syst. = Platyceras.
Neritomopsis WaacEN 1880, Pal. Ind. XI,

106.

Niso Risso 1826, Hist. IV, 218. Employed
by Dr Kontvcx in Fossiles Pal. de Nouv.
Galles du Sud 1876, 127, for a Devo-
nian species.

Odontomaria Frrp. Rormpr 1876, Leth.
Geogn. 1 Theil. Taf. 29, f. 10, Devonian.

Omphalotrochus Merk 1864, Rept. Geol. Sury.
California. Paleont. vol. 1, 16. Rela-
ted to Oriostoma, not a Pleurotoma-
rian as De Koninck thinks.

Onychochilus Lrxypstrém 1884, Silurian Ga-
stropoda of Gotland, 196.

Ophileta Vaxuxem 1842, Geol. N. Y. vol.
Ill, 36.

Oriostoma Munier-Cuatmas 1876, Journal
de Conchyl. vol. XVI, 103. Comprises
several paleozoic forms which have
been regarded as Euomphali, without
being provided with the characteristic
slit in the aperture.

BAND. 19. N:0 6. 203

Orthonena Mrrx & WortHen 1861, Proc.
Acad. N. Se. Philad., 146, Carbonife-
rous.

Orthonychia Hatt 1843, Rept. 4th Distr. N,
Y. Geol. Sury., 172. <A division of
Platyceras.

Orthostoma Conrap 1838, Ann. Rep. N. Y.,
119. Perhaps a disjointed Euompha-

lus, perhaps a Cephalopod.

Paleacmea Hart 1873, 23d Rept. N. Y.
St. Cab., 242.

Palewotrochus Hau
V, pt. II,° 133.

Patella L. 1758, S. N. ed. X, 780.

Patellostium WaAascen 1880, Pal. Ind. XII,
131. One of the Bellerophons.

Phanerotinus Sow. 1844, Min. Conch. vol.
Will; ;29:
disjointed whorls,
large cristate lamina along the dorsal
side. Is it related to the alate Pleu-
rotomari?

Phasianella Lamx 1804, Ann. du Muséum,
IV, 295. According to Waacen Pal.
Indica XII, 109, Carboniferous.

Phorus Mont¥rort 1810, Conch. Syst. II, 158.
According to Euprs-DESLONGCHAMPS,
Bullet. Soc. Linnéenne de Normandie
VI, 146 there is a Devonian species.

Phragmolithes Conrad 1838, Rept. N. Y.
Geol. Surv., 119. = Cyrtolites.

Phragmostoma Hatt 1861, 14th Rept. N. Y.
State Cab., 94.

Phymatifer De Konrtncx 1881, Faune II, m,
149. Related to Porcellia.

Pileopsis Lamx 1812, »Extrait d'un Cours» ete.
according to Herrmannsen Index H,
268. Anim. sans Vertebr. 1822, vol. 6,
2 p. 16. The fossil species of LAMARCK
are tertiary, the majority is recent.

Pilidion BARRANDE 1865, according to Bics-
By. Thes. Silur. 161, 168.

Pithodea Dr Kontnck 1881, Faune H, 1m, 88,

1879, Pal. N.Y. vol.

A very interesting form with
fa)
plano-spiral and a

204° G:

Pitonellus Montrort 1810, Conchyl. System.
Tak Z0;

Platyceras Conrad 1840, Ann. Rept. Geol.
Surv.) N.¥s205:

Platystoma (not Platyostoma) Conr. 1842,
Acad. Nat. Sci. Philad. Journ. 1839—
42,1275.

Platy(o)stomella R. Evruprines jr 1880, Proce.
R. Phys. Soc. Edinb., 163, Carbonif.

Platyschisma Mac Coy 1844, Carbonif. Foss.
of Ireland, 38.

Plectostylus Conrad 1842, Journ. Ac. N.
Sc. Phil. 1839—42, 275.
in 1837 preoccupied by Beck for a
Helicid shell.

The name

Pleuronotus Hatt 1879, Pal. N. Y. vol. V, |

pt. Il, 188. = Euomph. Decewi.
Pleurotomaria De France 1821 in FErus-
sac, Tabl. Syst., XXXIV.
Pleurotomarium Buatnvitte 1825, Malac.,
429, »male» HeRMANNSEN.
olyphemopsis PorrLock 1843, Rept. Geol.
Londonderry, 415, probably = Subu-

lites.

Polytremaria D’Ors. 1850. Prodr. I, 122.
Carbonif.

Polytropis De Kontyck 1881, Faune II, m1,
107. = Oriostoma.

Porcellia LiEvertté 1835, Mém. Soc. Géol.
de France II, 39.
Portlockia De Kon: 1881, Faune II, my, 81.
Priscochiton Biturncs 1865, Paleeoz. Foss.
Canada J, 394. Lower Silurian.
Proboleum Carpenter according to Dai
1882, Proc. N. S. Nat. Mus. 281, a
Devonian Chitonid.

Protalochiton Rocursrune 1882, Ann. Soc.
Geol. XIV, 30, Carbon.

Pseudophorus Merk 1873, Geol. of Ohio I,
222.

Pterochiton CarpENntTER according to Daui
1882, Proc. U. S. Nat. Mus. 281, Bel-
gium, Ireland, Carbonif.

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Ptychomphalus AGassiz 1837 in Gross-Bri-
taniens Mineral Conchologie von James
Sowerby. Deutsche Bearbeit. von Ag.,
23 and 222,

Pycnomphalus Lixpsrr. 1884, Silurian Ga-
stropoda of Gotland, 153.

Rhabdopleura Dr Kon. 1881, Faune I, m, 75.

Rhaphistoma Haut 1847, Pal. N. Y. J, 28.

Rhineoderma Dr Kon. 1883, Faune, I, 1v, 103.

Rhombochiton Dp Kon. 1883, Faune II, rv, 206.

Rotella Lam. 1822, Hist. VII, 6. According
to Dr Koninck a fossil species occurs
in the Carbonif. form. of Belgium.

Rotellina Dr Kon. 1888, Faune I, rv, 92.

Sagmaplacus OruLert 1881, Mém. Soe.
Geol. de France 3me Ser. Tome II, 15
a Chitonid.

Salpingostoma Frrp. Rormer 1876, Leth.
Geogn. Taf. 5, £12

Scevogyra WutrrieLp 1877, Paleontology
of Wisconsin, 2538.

Sealites Conrad 1842, Emmons Geol. Rep.,
a2.

Scissurella D’Ors. 1823, Mém. Soc. H. N.
Par. I, 340.

Schizostoma Bronn 1835, Lethea, Ed. 1 vol.
lle QAaxe

Scoliostoma M. Braun 1838, N. Jahrbuch, 291.

Serpularia A, F. Rormer 18438, Geol. Harz-
gebirge, 31. = Pleurotomaria.

Siphonaria Sow. 1824, Gen. of Shells, pl.
143. Used by Barranpbe according to
Biessy, Thes. Sil., 168 for a Bohe-
mian Patelloid.

Solarium LamK 1801, Syst. anim. s. vert.
86. De Koninck used 1843 this name
for Euomphalus or Pleuronotus.

Soleniscus’ Mrrex & Worruen 1860, Proc.
Ac. N. Se. Philad., 467, Carbonif.

Spirorbis, SrerNinGer 1831, Bemerkungen
itiber die Verstein. in der Eifel. Srer-
NINGERS Sp. maximus belongs to the
Devonian Euomphalus.

KONGL. SV. VET.

AKADEMIENS HANDLINGAR.

Stachella WAacEN 1880, Pal. Ind. XII, 132. |

Stomatella LamK 1809, Phil. zool., I, 321.

Used by Barranper accord. to Biassy |

Thes. Sil., 168.

Stomatia LamK 1801, Syst. anim. s. vert.,-

96. Pricrer and Juertnc think that
there are Silurian species.

Straparollina Brruines 1865, Palwoz. Foss.
of Canada, 223.

Straparolus Montrort 1810, Conch. syst.
Wye W44.

the French »Rouleau».
Strobeus Dr Kon. 1881, Faune IJ, m1, 25.
= Elenchus Mac Coy not Humpnrey.
Strophites Dawson 1880, Amer. Journ. Sc.
& Arts 3d Ser. vol. 20, 412.
vonian Landshell?

Strophostylus Hatt 1859, 12th Rept. N. Y- |
Probably a Platyceras. |

St. Cab., 20.

Subulites Conrap 1842, N. Hist. of N. Y.,
vol. II, 392.

Sulcochiton Rycxuour 1862, Journ. Conch.
X, 259.

Terebra Apanson 1757, Seneg., 49, used
by Sowersy for Loxonema_ sinuosa.
Sil. Syst.

Trachydomia Merx and Worrnen 1866,
Geol. Survey Illin. vol. 2, 8364. Carbonif.

Tremanotus Hatt 1868, 20th Rept. N. Y.
State Cab. 399.

Trochilites ScutoTHem 1820, Petrefakten- |

kunde, 156.

Trochita Scuum. 1817, Essai, 184, Mac Coy
Carbonif. Foss. Irel., considers a fossil
to belong here. There are also other
palwozoic species by mistake referred
to this genus.

Trochonema Saurer 1859, Canad. Organ.
Remains I, 27.

Trochotremaria Rycxuout, Carbonif. of Bel-
gium aecording to Zirret Paleont. Bd
it, 2, 881:

Derived from o7ee/0s, tor- |
sus, and Rollus, a barbarous word for |

A De- |

BAND. 19. w:o 6. 205

Trochus L. 1758, S. N. Ed. X, 756.

Tropidocyclus De Kontnck 1882, Mém. Soc.
Geol. de Belg. t. IX, 12.

Tropidiscus Mrrx 1866, Proc. Chic. Acad.
Se. vol. I, 9. = Cyrtolites.

Tropidodiscus W AAGEN 1880 Palzont. Indica,
XIII, 131, name of the former emen-
dated by WaacGen.

Tryblidium Lrxpstr6m 1880, in Fragmenta
Silurica, 15.
Tubina Barr. 1860,

logy, 71.

Turbina De Konrnck 1881, Faune I, 10, 67.

Turbinilopsis De Kon. 1881, Ibid. 89.

Turbinites ScutoruH. 1820, Petref.-kunde
163, WAuLENBERG applied it to several
species of Oriostoma.

Turbo L. 1758, S. N- X, 761, Picter and
D’OrpicnNy gave this name to several
of the Oriostomata and Cyclonemata.

Turbonellina Dr Kon. 1881, Faune II, 1, 77.

Turbonitella De Kon. 1881, Faune II, m, 72.

Turritella LamK 1801, Syst. anim. s. vert.
89. Used for Murchisonia and other
spirally wound shells by several au-
thors.

Tychonia De Kon. 1881, Faune I], m, 7.

Umbonium Linx 1807, Beschreib. Rostocker
Samml. III. 136, Devon.

Vasulites HERRMANNSEN 1849. Index JI, 677,
cites it as used by Monrrort in »Suites
a» Burronn-Sonint IV, 298.

Waagenella De Konincx 1883, Faune II, tv.
Explic. des planches n:o 38, for
Waagenia De Kontncx 1882, Ann. Soc. Geol.
de Belgique t. IX, 14, which name had

already been preoccupied.

Warthia WAaGEN 1880, Pal. Indica XIII, 151.

Worthenia De Kon. 1883, Faune III, rv, 64.

Xenophora Fiscoer von WaALDHEIM 1806,
»Museum Demidowianum, 213». Merk
and WorrHEN ranked a Carbonif. spe-
cies in this genus.

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KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. w:o 6. 207

PLATE I.

The originals to the figures belong to the Swedish State Museum of Natural History in Stockholm, unless otherwise stated.

208
Fig. 1-— 3.
» A—— 8
» 9—12
» 13—16
» 17-24.
» 25—31.
» 2s
» 33—37.
» 38—39.

G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Pxiate lI.

Conularia cancellata SanpB. pag. 42. Fig. 1 spines on the lowest row with broken points,
whence the circular openings, f.. 2 part of two transverse ridges highly magnified, f. 3
longitudinal section. ‘The long spines are those on the ridges, the short ones are sections of
the ridges where no spines are found.

Conularia bilineata n. p. 45. F. 4 lateral view, f. 5 section near the upper margin, f. 6 surface
near the apex magnified, f. 7 the same higher up between the two median septa, f. 8
ornamentation in lower part of the shell.

Conularia monile n., p. 44. F. 11 transverse lines magnified and sectioned longitudinally, f. 12
transverse section of transverse lines.

Conularia levis n., p. 45. Fig. 15 transverse section of specimen fig. 13., fig. 16 surface of
fig. 14 enlarged.

Autodetus calyptratus Scurenk, p. 185. Fig. 17 shell in its natural position and grown on a
Favosites, figs 17a— 22 other specimens and details of apex and umbilicus, fig. 24 part
of the longitudinal section magnified to show the cellular structure outside the whorls.

Tryblidium reticulatum n., p. 55. Fig. 27—28 apex of a young specimen, f. 29 interior stratum
with traces of colour bands, f. 30 muscular sears of the inside, f. 31 longitudinal section
of the shell.

Patella (Olana) cochlear 1. Recent. Inside to show the muscular scars.

Tryblidium unguis n., p. 56. Fig. 36 inside of apex with oval pit like a sear, f. 37 inside of
shell with muscular scars.

Nacella deaurata Gmeputy, recent from Foua, to compare the exterior shape with the preceding.

K Vet. Akadem. Handl.Bd.19 N° 6 G.Lindstrom: Silurian Gastropoda of Gotland P11

sei

Central-Tryckenet, Stockholm

G. Liljevall del2 lith

» yin! nu? ' ! he at :} , : t ht "
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210 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

1— 4.

H—= ish

9—10.
11—15.
16—17
18—27
28.
29—31.
32—36.
37— 38.
39—40
41—43
44—45.
46 —A47.
48.
49—50
51
52.
53—57
58.
59—72
73—78

Puate II.

Chelodes Bergmani Davipson & Kine, p. 51. Same specimen as figured by Davipson.

Another specimen also from Klinteberg, 7—8 in natural size.

Chelodes Gotlandicus n. p. 52, from Grétlingbo.

A specimen from Grotlingbo, f. 13—14 nat. size.

A specimen from Bursvik, nat. size.

Shorter valves from Grétlingbo, f. 20—21 nat. size.

Chiton sp. indet. Recent. Interior side to compare with fig. 25.

Platyceras cornutum HIsincEr p. 63.

From Wisby, details of ornamentation magnified. ns

From Faro, f. 32—33 resembling Nerita haliotis Sow., 34—36 like a Ianthina.

From Eskelhem, »Strophostylus».

Large specimen from Faré, nat. size.

From Klinteberg, with lobate aperture. Compare Plat. niagarense Hatt the 28 Rept. N. Y. St.
Cab. pl. 28 f. 2—4.

Nucleus from shale beds of Wisby.

From Klinteberg, loosely coiled.

From middle limestone of Wisby.

From Klinteberg, disjointed whorls.

Drawn from Hisincer’s original specimen to »Pileopsis cornutay as exact as possible, nat. size.

Drawn from HisiNcer’s original specimen to »Pileopsis suleata» being corroded sample of the
following variety, nat. size.

Variety »loricatum» from Klinteberg f. 55 umbilical side, f. 56 the apical one.

Craspedostoma elegantulum n. p. 183.

Platyceras enorme n. p. 69, various specimens, with details of ornamentation, all from Rikvide
in the parish of Nar.

Platyceras disciforme n. p. 68, from the sandstone of Hoburg in nat. size, ornamentation highly
magnified.

K Vet Akadem.Handl.Bd.19 Ne 6

G Lindstrom: Silurian Gastropoda of Gotland PLII

G. Liljevall del.& ith

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Fig.

212

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6— 9
10—18.
19—26
27—31.
32—34.
35—38.
39—40.

G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Prate Ill. ,

Tryblidium reticulatum n. p. 55. Fig. 1 & 2 microscopical vertical and horizontal sections of the
shell, showing its strata perforated by tubes of unknown, parasitic organism, f. 3 another
vertical section, f. 4 vertical section with apparently tubular structure, formed by small de-
pressions or pits on the surface of the shelly strata, f. 5 sarface of shell from the margin
of the aperture, magnified; the elevated, white dots being the filled up tubes of the parasitic
organism.

Platyceras cornutum His. p. 63. Fig. 6 from Klinteberg, with aperture evidently moulded
after the surface of some other organism on which it had been fixed, f. 7—9 from Wisby.
Platyceras prototypum Puiu. p. 67. Fig. 10—10 a from Klinteberg, f. 11—12 from the shale of
Wisby, identical in ornamentation with specimens of Platystoma niagarense, f. 13—14
from the hill of Sandarfve, f. 15 ornamentation of the same and profile of a transverse ridge,
f. 16 a pair of its apertural lamelle, f. 17 vertical section of seventeen lamelle, as they
were left in situ imbedded in soft limestone, slightly magnified, f. 18 one of the lamella

highly magnified to show its intimate structure.

Platyceras cornutum His. p. 63. Fig. 19—22 vertical sections of the shell, f. 23 interior surface
of the shell seen under the microscope; f. 24 part of the same still more magnified, f. 25—26
horizontal sections of the shell.

Oriostoma helicinum n. p. 170, from the canal near Westéds in Hall.

Craspedostoma spinulosum u. p. 182, from Hoburg, f. 34 nat. size.

Bellerophon sphera n. p. 74, from the shale of Wisby.

Tremanotus longitudinalis n. p. 86, from Lutterhorn in Faré, with apertural expansions left in situ.

Glindstrom: Silurian Gastropoda of Gotland P1. Ill

——
G Liljevali del.& lith

re 3S 4 isi} he

2138

&

»

»

214° G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Puate IV.

1— 7. Tremanotus longitudinalis n. p. 86, all specimens from Wisby, f. 5 dorsal keel with apertures,
from a cast, f. 6 magnified details of the same, showing septa like, curved lines, going
transversally, marking where apertural lamelle have been situated. -

8—12. Tremanotus compressus n. p. 87, from Ostergarn.

13—15. Bellerophon trilobatus Sow., p. 80, from Petesvik, Habblingbo.

LIV.

otland P.

Ui

dstrom: Silurian Gastropoda of (

G. Lin

iijevall del. ith

1
L

K Vet.Akadem. Hand] Bd.19 N°6

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215

216 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PYTEROPODA OF GOTLAND.

Pirate V.

Fig. 1—16. Bellerophon sphera n., p. 74. Fig. 3 cast of »dorsal» part with the elevated slit band and section
of the same, f. 4 the same from the side, f. 7, surface of a variety with lateral view and
section, f. 8 slit band enlarged, f. 10 section of the innermost whorls, with the hooklike
lamelle of the surface, f. 12 section of a large specimen with exceedingly thick walls around
the umbilicus, f. 13—16 details of surface sculpture around the umbilicus.

» 17—24. Bellerophon squamosus n., p. 78. Fig. 17—19 specimen in nat. size, f. 20 smaller specimen in
natural size and its slit band in f. 21, f. 23 section of the shell with the thin lamellar processes
from the lines of growth, f. 24 curves formed by the extreme edges of these lines of growth,
sectioned horizontally.

» 25—34. Bellerophon globulus n., p. 75. Fig. 34 enlarged view of the umbilicus.

urian Gastro

Hil UP

26.

i

K Vet. Akadem.Handl.Bd.19 1

19

Central-Tryckerié

G.Liljevall del.& lith

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218 G.

1—10:
11—12
13—14
15—18
1G)
22—25
26—28.
29—30
31—38
39—51
52—53
54—55

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Pirate VI.

Bellerophon fastigiatus n., p. 76. Fig. 10 side of the largest whorl.

» undeterminated species, p. 77, sections showing the great obliquity of the shell.

» fasciatus n. p. 75.

» ’ elegantulus n. p. 79.

» Ejiseni n. p. 78. "

» tenia n. p. 76. Specimens from Ostergarn, original to f. 22 belongs to the

Museum of the School of Wisby.

Bellerophon latevittatus n., p. 79.

» miula n. p: SOPs = :

Cyrtolites lamellifer n. p. 82, f. 37 details of ornamentation and lateral view of the outstanding
lamelle, f. 38 the slit band near the aperture, much magnified.

Cyrtolites pharetra n. p. 83. Fig. 39 specimen with traces of colour bands, magnified, f. 43
lower lip of the aperture, f. 50 groove beneath the inferior apertural lip, in which the apex
of the shell is lodged.

Cyrtolites arrosus n., p. 83.

» obliquus n., p. 84.

G. Lindstrom: Silurian Gastropoda of Gotland P1 VI

K Vet. Akadem. Hand] B. 19 N°6

G.Liljevall del.& lith.

a

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;

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MIENS: HANDL. BAND. 19. N:o 6.

‘PLATE VIL.

—

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219

aa

220 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Puate VII.

1— 3. Conularia aspersa n. p. 46.

4— 5. Bellerophon tenia n. p. 76. The original specimen belongs to the Mineralogical Museum of

the University of Copenhagen, from Ostergarn.

6— 8. Bellerophon latevittatus nu. p. 79. Nuclei from the shale of Wisby, with a peculiar, transverse,
1 Pp Ys Pp

necklike constriction.

ie Bellerophon sphera n., p. 74. Microscopic, vertical section of the shell.

10—15. Cyrtolites euryomphalus nu. p. 84.

16—17. » orbieulus n., p. 85.

18—21. » discus n. p. 84, the original specimen belongs to the Museum of the Geological
Survey of Sweden.

22. Platyceras cyathinum n. p. 69.

23—25. Pleurotomaria scutulata n. p. 95.

26—27. » gradata un. p. 96.

28—30 » scutulata u. p. 95. Fig. 28—29 from Samsugn, f. 30 from Follingbo.

31—36. » claustrata n. p. 97. The original specimen of f. 34 belongs to the Miner.

Museum of Copenhagen.
37—38. Pleurotomaria glandiformis n. p. 98.
39—42. » biformis n. p. 98. Fig. 42 magnified details of slit band.

43—49. » Lloydi Sow. p. 101, f. 43—44 from Djupvik, Eksta, f. 45—46 from Petesvik in

Habblingbo, 47—49 from Wisby.

:

==
/

KVetAkadem.Handl.B.19.Ne6 G Lindstrom: Silurian Gastropoda of Gotland P). V1
Se

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222. (G: LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Prats VIII.

il, Pleurotomaria Lloydi Sow., p. 101.

Y= 1 » robusta, n. p. 103. Specimen from Eksta. .

Ss) es) » o> var. lavissima n. p. 104. x

10—14. » elliptica His., p. 104, f. 10—11 from Wisby, 12—13 from Ostergarn. Fig. 14 slit

band magnified and section of it, from Lerkaka in Oland.

15—25. Pleurotomaria bicincta Hauu, p. 106. Fig. 15—16 specimen from Westergarn, f. 17 from
Borkholm in Esthonia, belonging to the Mineral Cabinet of the University of Upsala, f. 18—19
large specimen in natural size from the limestone of Slite, belonging to the Marklinian
Collection of Upsala, f. 20 specimen natur. size from Ardre, f. 21—22 details of slit
band, specimens from Follingbo, f. 23 slit band of specimen from Firé, f. 24—25 from
Gothemshammar.

G.Lindstrom: S

K Vet Akadem.HandI.B19 Ne6.
—

G.Liljevall del & lith

~~ > —_——" 7 Sow _
es >

a¢-<a ee
_ KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 545

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PLATE IX.

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224° Ge

toe
4— 6
TOE
11—13
14—17
18—19
20—29
30—38.

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Puate IX.

Pleurotomaria dolium n., p. 102.
» laqueata u., p. 102, f. 4 the original specimen belongs to the Museum of the

School of Wisby, f. 5—6 from Klinteberg.
Pleurotomaria tubulosa n., p. 103 from Kraklingbo.

» valida n. p. 110.

» Othemensis n. p. 111, f. 17 the umbilicus seen from above.

» comata n. p. 111 from Eksta.

» equilatera WAHLENBERG p. 111, f. 20—22 the original specimen of WAHLENBERG

from the Mineralogical Cabinet of the University of Upsala, somewhat restored as to the
aperture and sections of the slit band, f. 23—24 from Kyrkberget in Wisby, f. 25—26 from
the shale of Wisby, f. 27 ventricose variety from Samsugn.in Othem, belonging to the Min.
Cab. University of Upsala, f. 28 from Samsugn in Othem, f. 29 section of two whorls to
show the shape and place of the slit band.

Pleurotomaria labrosa Hatt, p. 113, fig. 30—36 from Westergarn, f. 37—38 from Klints
in Boge. Fig. 36 section along the median axis of the slit band.

K Vet Akadem.Hand1.B.19 N° 6.

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Fig.

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18—32.
33—37.
38—40.

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

PLATE X.

Pleurotomaria latezonata n., p. 99.

» limata u., p. 114, f. 2—5 from Klinteberg, f. 6—9 from the middle limestone
strata of Wisby, f. 10—11 variety from the canal near Westéds in Hall, f. 12 specimen from
Wisby seen from the umbilical side with a largely developed slit band, f. 13 details of
ornamentation of the slit band and the surface around the umbilicus, f. 14 transverse section
of the slit band, imbedded in fine grained rock, f. 15—16 slit band of two different specimens,
magnified, f. 17, part of a slit band cloven in two parts along its median line to show how
the crescentic lamellae continue outward to the thin bordering lines.

Pleurotomaria alata H1s., p. 116. All the originals to the figures from Wisby. Fig. 23,
near the aperture the cresceutic lamellae between the bordering laminw are conspicuous as
black lines below the surface and they are partially restored by dotted lines where they have
been broken away, f. 24 inferior surface showing the wavy edge of the slit band, f. 25
ornamentation of umbilical surface, f. 27 details to elucidate the structure of the slit band,
f. 28 omamentation of apical surface from a specimen with a ridge, f. 30 transversally
sectioned slit band, magnified, f. 31 extreme edge of a slit band, f. 32 variety from Wisby
with downwards anh inwards curved slit band.

Pleurotomaria alata, var. subcarinata n., p. 118, f. 33 specimen from Lingsarfve in Nis, enclosed
in an oolitic nodule, figs 34—37 from Djupvik in Eksta.

Pleurotomaria alata, var. opposita n., p. 119, from Habblingbo, f. 39 apical side of body
whorl and part of next whorl, f. 40 ornamentation of umbilical side and slit band.

uahG Fi A

K. Vet Akadem.Handl B.19 Ne 6. G.Lindstrém: Silurian Gastropoda of Gotland P] X

Georg Liljevall, del. 1th

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15—23.
24— 26
21—29
30—33
34—37

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Priatse XI.

Pleurotomaria preterta n., p. 119. Fig. 5 the slit band cloven, the lower stratum shows the
oblique, cresceutic lamelle of the slit band. Fig. 7 part of the surface around the slit band
and its both parallel ridges.

Pleurotomaria togata u., p. 119. Fig. 12 part of apical surface from the suture to the rim of
the slit band, f. 13 longitudinal section along the whorls.

Pleurotomaria frenata n., p. 120.

» undulans n., p. 120. Fig. 21 with details of the structure of the slit band.
Fig. 22 slit band sectioned along the outer rim, f. 23 slit band sectioned transversally.

Pleurotomaria Marklini n., p. 121.

» cirrhosa n., p- 121 longitudinal section, f. 29 part of apical surface witb the
thin, wavy slit band solded to the body whorl, f. 28 section of the same.

Pleurotomaria exquisita n., p. 125, f. 33 section of two whorls showing how the superior
one is overlaying the inferior. ~ ;

Pleurotomaria helicina u., p. 124.

K.Vet.Akadem. Handl.B19 Ne 6

GLindstram: Silurian Gastropoda of

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PLATE XII

230 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

1— 3:
4.

i= @
ie

8.

910:
11—12.
13—14.
15—19
20—24.

Puate XII.

Pleurotomaria cirrhosa n., p. 121, specimen from Ostergarn, with details of surface.
Murchisonia cava n., p. 128, from Martebo and details of the slit band.

» moniliformis n., p. 128, from the sandstone of Bursvik.

» obtusangula n., p. 128.

» subplicata n., p. 129.

» cingulata His. p. 127, f. 9 the type specimen of Hisincer, which he delineated

in »Letheea Suecica» on pl. XI fig. 6 a. In natural size.
Murchisonia obtusangula n., p. 128.

» crispa n., p. 131.

» compressa n., p. 129. Fig. 15, nucleus with traces of sculpture, fig. 17 one
of the largest nuclei with an obtuse end above the filled up apex, fig. 18 longitudinal
section along the median axis, fig. 19 transverse section of the apex, showing the dark
apical whorls, filled with organic deposit, and the lighter nucleus of the younger whorls.

Murchisonia attenuata Histncer p. 130.

K Vet Akadem. Hand1.B19 Ne 6

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. AKADEMIENS HANDLE. BAND. 19. N06. 281

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4— 5.

6.

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13—14
15—16
ile.
1931
32—35
36 —38
89—44

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Prate XIII.

Murchisonia cancellata n., p. 133.

» cochleata n., p. 134.

» tortuosa n., p. 132.

» munda mm, p. 132.

> imbricata n., p. 1383. Fig. 7 slender, finely striated variety; fig. 8 the thicker and

more coarsely striated, f. 9—12 details of aperture, umbilical region and slit band.

Murchisonia tortuosa n., p. 132.

Pleurotomaria qualteriata Scutoru., p. 108. Fig. 15 from the shale of Wisby. Fig. 16
ornamentation and slit band in specimen from Lerkaka, Oland.

Pleurotomaria obvallata WanLENB., p. 108. Fig. 17 section of the shell, f. 18, details of the
slit band; lowest figure, slit band on the apical side; middle figure, section of the edge,
uppermost figure, slit band from the umbilical side. From specimens belonging to the
Museum of the Geol. Survey of Sweden from the upper gray Orthoceratite Limestone at
Wangsgirdet in Dalecarlia.

Euomphalus Gotlandicus n., p. 139. Fig. 19—25 specimens from the shale of Wisby. Fig.
26—29 evolute specimens from Kyrkberget in Wisby, the mucleus lying beside the shell, the
apex of which is filled with organic deposit; fig. 30—31 from Westergarn.

Euomphalus triquetrus n., p. 140.

» Angelini n., p. 138. Lower Silurian from the inferior gray Orthoceratite Limestone
at Utby, Lindgarden in Dalecarlia, fig. 38 sculpture on the lateral surface.

Pleurotomaria replicata n., p. 116. Fig. 39 from the aperture, apical side downwards, f. 40
from the umbilical side, f. 42 slit band magnified, interiorly the oblique crescentic lamelle
are seen, f. 43 transverse section of slit band, f. 44 slit band along is exterior edge.

KVet.Akadem.Handl.B 19. N26.

ADEMIENS ‘HANDL. BAND. 19. N:0 6._ 233

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234 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

1—1 1h.
12—13
14—17
18—21
22—31
32—34
35—43
44.

45.

46—53
54—58
59— 69

Priate ‘XIV.

Trochus Gotlandicus n., p. 146, fig. 1—2 from Kyrkberget, Wisby, 3 from the limestone (b.)
of Wisby, 4—7 from the canal near Westéds in Hall f. 8, var. without ridge from Kyrk-
berget in Wisby, f. 9 microscopical section of the ‘shell, f. 10—11 from the limestone
of Wisby.

Trochus fulminatus n., p. 147. ‘

» mollis n., p. 147, f. 14—16 from Klinteberg, f. 17 from Samsugn.

» Dalli n., p. 150.

» meisus n., Pp. 151. Fig. 22—23 from Kyrkberget in Wisby; f. 24—25 from Samsugn
in Othem; f. 26—80 from Stor Wede in Follingbo; f. 31 from Kyrkberget in Wisby.

Trochus Kolmodini n., p. 150.

» Wisbyensis u., p. 150. All species from the limestone of Wisby, excepting f. 43
from the canal near Westéés in Hall.

Trochus lamellosus n., p. 151.

» Wisbyensis n., p. 150.
» Tundgreni n., p. 149, fig. 46—50 from Samsugn in Othem, f. 51 from Lutterhorn in
Faro, f. 52 transverse section of the keel showing different lines of growth hidden inside it,
f. 53 the keel from without.

Trochus astraliiformis u., p. 153, from Klinteberg, specimens figures 56-——57, belonging to
the Marklinian Collection in Upsala.

Trochus Stuebergi n., p. 147. Fig. 59—61 from Klinteberg, f. 62—69 from Samsugn in Othem,

KVetAkadem Handl.B 19 N2

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48.
49.
50—51
52—54
55—58
59—60
61.
62.
63.
64—67

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

PLATE XV.

Loxonema sinuosum Sow. p. 142, from Djupvik, Eksta.

» intumescens n., p. 143.

» sinuosum Sow. bs

» strangulatum n., p. 144, f. 8—9 from Klinteberg, f. 10 from Ostergarn.
» fasciatum n., p. 144.

Holopella regularis n., p. 190. The original belongs to Adjunct M. Kuinrsere in Wisby.
Macrochilina bulimina n., p. 191.

» fenestrata n., p. 192.
Subulites ventricosus Haut p. 193.
» attenuatus n., p. 194.

Callonema scalariforme u., p. 189. The original to fig. 26 is preserved in the Museum of the
School of Wisby.

Callonema obesum n., p. 189. The original belongs to the Mineralogical Museum of the
University of Copenhagen.

Cyclonema delicatulum u., p. 174. The original to fig. 30—31 belongs to Hr H. Hepsrrom
in Wisby.

Probably a corroded specimen of the former.

Holopea applanata n., p. 188.

Subulites attenuatus n., var. p. 194.

Cyclonema adstrictum u., p. 178.

Holopea nitidissima n., p. 188.

"rochus? lamellosus var. p. 151. The original from the Mineralogical Cabinet of the University
of Upsala.

Onychochilus physa n., p. 196. The originals from the Min. Cab. of the Univ. of Upsala.

Holopea transversa n., p. 188.

Holopella teres n., p. 190.

Holopea nua n., p. 187.

Holopella minuta n., p. 190.

Pycnomphalus obesus n., p. 153.

G. Lindstrom: Silurian Gastropoda of Gotland Pl. XV

ny

G.Liljevall del f

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KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 237%

PLATE XVI.

238 G. LINDSTROM, ON THE SILUKIAN — AND PTEROPODA OF GOTLAND.
goon oe.

Pirate XVI.

1— 6. Pycnomphalus acutus n., p. 154. From Wialmsudd.

7 » trochiformis n., p. 154. The original belongs to the Museum of the School of Wisby.
8—10. Trochus undulans n., p. 148. Fig. 8 from Samsugn. Fig. 9—10 from Slite.

11—13. » profundus n., p. 148. This species is probably rather to be considered as an Onustus.
14—19. Oriostoma alatum n., p. 171.

20— 36. » discors Sow., p. 157. Fig. 20—28 from Westergarn, f. 29 from Faré, Lutterhorn,

f. 30 from Kyrkberget in Wisby, f. 31 from the canal in Hall, f. 32—83 from Kyrkberget
in Wisby, f. 34—36 from the canal in Hall.

K Vet. Akadem. Handl. B.19 N°6.

2 —
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32—35
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41—42
43—44
45—46
47.
48.
49.
50—52
53 —55
56.
57

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Prater XVII.

Oriostoma discors Sow., p. 157. Fig. 1—2 from Hall, f. 3-—-5 from Wisby.
i Me aD var, rugosum Sow. p. 159. Fig. 6—7 from Norderstrand near Wisby, f. 8—9
from Ostergarn, f. 10 from Martebo.
Oriostoma coronatum n., p. 174. -
Operculum of an unknown Oriostoma from Ostergarn making a new type, besides those described
in the letter press, where it has been accidentally omitted.
Oriostoma coronatum n. Opercula.

» globosum ScuLoruEm, p. 160. Fig. 24 from Westergarn, f. 25 from Samsugn.
» Wisbyense n., p. 167.
» globosum ScunorH. from Martebo. p. 160.

Opereula of unknown Oriostoma from Martebo p. 165.
Operculum from Martebo p. 167.
Oriostoma acutum n., p. 166.
» globosum Scuuor. var. sculptum Sow., p. 162.
Opercula from the shale bed of Wisby, p. 167.
Oriostoma Wisbyense, n., p. 167, the operculum.
Operculum of unknown Oriostoma from Kilens Qvarn p. 167.
Cyclonema striatum His. p. 177 the operculum from Samsugn in Othem.
Operculum of unknown Cyclonema from Slite p. 177.
Opercula of unknown Cyclonema from Ostergarn p. 177.
Opercula of unknown shell from shale and limestone of Wisby, p. 169.
Section of an operculum from Samsugn, genus and species unknown, p. 169.
Operculum of unknown shell, natural size, from the shale beds of Wisby p. 170.

K Vet. Akadem. Handl. B19 N°6 G. Lindstrom: Silurian Gastropoda of Gotland PI. XVII

G. Liljevall, del. & lith. Central-Iryckeriet Stockholm

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6— 8.
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18—21
22—23
24.
25—27
28—29
30.
31—32
33—35
36.

37.

38.
39—42
43—44
45.
46—47
48—49
50—51
52—53
54—57
58—59
60—61
62.
63—64
65—68
69.

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Prats XVIII.

Tryblidium radiatum n., p. 58.

Loxonema? attenuatum n., p. 143.
Euomphalus tuba n., p. 140.
» precursor n., p. 140.
» Walmstedti, n., p. 141.

Trochus cavus u., p. 149. If not rather an Onustus?

» gyrans n., p. 152.

» densestriatus n., p. 152.
Oriostoma globosum Sow. p. 161. Microscopic section of two coils of the operculum.
Cyclonema cancellatum n., p, 175.

» carinatum Sow., p. 178.

» carinatum, var. glabrum n., p. 179.

» carinatum, var. multicarinatum n., p. 179.

» nodulosum n., p. 179.

» apicatum n., p. 175.

» distans u., p., 176.

» tenuissimum n., p. 180.

» striatum His., p. 176. Fig. 39 is from the original of Histncer, preserved in the

State Museum at Stockholm. Fig. 41—42 from Samsugn.
Cyclonema zonatum n., p. 178.
Holopea perforata n., p. 188.
Macrochilina cancellata n., p. 191.
» bulimina n., p. 191.
Pleurotomaria Wisbyensis n., p. 100.
Trochonema muricatum u., p. 181.
Onychochilus cochleatum n., p. 197.

Subulites ventricosus p. 193.
» ventricosus, var. curvus n., p. 194.
» attenuatus n. p. 194, transverse section.

Daphnella limneiformis L. Recent, to compare with the aperture of Subulites and Euchrysalis,
f. 63 transverse section.

Euchrysalis lineolata n., p. 195.

Turritella sp. Recent, transverse section to compare with those of the preceding shells, showing
the dissimilarity in holostomous and siphonostomous shells.

K. Vet. Akad. Hand]. Bd 19, Ne 6

C. Hedelin del

i kan Ae Alrite nt aoe mn hi dives iP
pit wile ef: dition, —. rebteagpy ve tnd ;

ff piitonw tt tel iil

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hee YAP hina

=
Sits

244 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

We

2.

3— 4
5.

==1il
12—14.
1G
17—20
21—24
25—29
30-—39

Prars XOX

Conularia aspersa n., p. 46.

Tryblidium unguis n., p. 56. Fragment of a shell with well preserved muscular scars, five pair
on each side, and on the left hand, upper figure, three enlarged, especially to show the
intimate structure of the largest sear.

Paleacmea solarium n., p. 59. Fig. 4 nat. size.

Platyceras disciforme un., p. 68.

Bellerophon tubulosus n., p. 77.

» gemma u., p. 80.
Pleurotomaria Hindei u., p. 99.
» Holmi n., p. 100. Fig. 20 from original in the Museum of Wisby.
» Linnarssoni n., p. 96.
» voluta n., p-, p. 97.
» planorbis His., p. 122. Fig. 34 part of the apical surface, near the suture, slit

band changed into an angulated ridge, f. 35—86 part of the apical surface, f. 37 aperture,
enlarged, from the apical surface to show the slit and the band. Fig. 39, slit band enlarged.

126.

9N

4
L

K Vet Akad. Hand]. Bd

—_ 1

KONGL. SV. VET. AKADEMIENS HANDL.

~

PLATE XX.

BAND.

19.

N:0 6.

246 G.

ee
7.
8—15.
16.
17—21
2229.
30—33.
34—41
42—44

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Pirate XX.

Murchisonia deflera n., p. 134. Fig. 3 the shell surface with the partially covered slit band.
Loxonema fasciatum u., p. 144. :
Oriostoma contrarium n., p. 160. Fig. 8—9, from Hall, f. 10 from Kyrkberget in Wisby,
f. 11—15 from Samsugn.
Oriostoma globosum ScuLoru. p. 160.
» angulifer n., p. 167.
» Roemeri u., p. 168.
» helicinum n., p. 170. Fig. 30—31 with colour bands from Samsugn, f. 32 from the
canal in Hall, f. 33 from the uppermost limestone of Halls huk.
Oriostoma angulatum WAHLENBERG, p. 171, f. 34—37 from Faré, f. 38—41 from Samsugn
in Othem.
Oriostoma lineatum n., p. 173.

4h

43

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KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 247

PLATE XXI.

248 «OG.

1— 3.

4—10.
11—14.
15—19
20—29
30—34.
35—38.
39—42.
43—54.
55—56.
57— 60.
61—65.
66.

LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Pirate XXI.

Murchisonia paradova n., p. 131.
Oriostoma nitidissimum n., p. 173. Fig. 4—7 from Sandarfve, f. 8—10 from Follingbo.
» dispar n., p. 173.

Trochonema turritum n., p. 181.

Craspedostoma ‘elegantulum n., p. 183, f. 20—24 from Samsugn, f. 25—26 from Slite, f.
27—28 from Follingbo, f. 29 from Klinteberg. Fig. 23 part of the surface enlarged, the
left side covered with rock as common, the transversal ribs only visible; f. 24 transversal
section of the columellar lip, where it is bifid, f. 26 part of the surface; in the inferior
figure the lighter, wavy parts between the darker, broken edges of the transverse ribs are
formed by calcareous mud on which are seen impressions of the now missing, backwards
reflexed edges of the ribs. The upper figure, a longitudinal section of the inferior one,
elucidates this, the dark portions being the shell and the curved ribs, their continuation
marked by dotted lines, the light mud filling the interspaces. ‘

Craspedostoma brevispira n., p. 183. Fig. 32 surface partly covered by rock, partly free.

» jilistriatum u., p. 183.

» involutum n., p. 184. Fig. 42 transverse section of columella, showing how it is
bifid as in the other species.

» glabrum n., p» 184. Fig. 49 section across the outer lip and partly across the

body whorl. The superior branch being the lip, the inferior one the shell, the inside of the
aperture being to the right.

Cyclonema perversum n., p. 180.

Autodetus calyptratus ScHRENK, p. 185, young specimens.

Onychochilus reticulatum n., p. 196.

Cyclonema sp. indet. operculum from Westerbys in Ardre, p. 177.

K Vet Akad. Handl.B.19.Ne 6 Le. ; J ___GJindstrém: dih

G Liljevall del & lith.

KONGL.

Acroculia
cornuta, 64.
euomphaloides, 64.
haliotis, 64.
prototypa, 67.
sulcata, 64.

Anticalyptraa
calyptrata, 185.

Autodetus, 185.
calyptratus, 185.

Bellerophon, 72.
dilatatus, 86.
Eiseni, 78.
elegantulus, 79.
fasciatus, 75.
fastigiatus, 76.
gemma, 80.
globulus, 75.
Jatevittatus, 79.
pilula, 80.
sphera, 74.
squamosus, 78.
tenia, 76.
trilobatus, 80.
tubulosus, 77.

Callonema, 189.
obesum, 189.
sealariforme, 189.

Calyptrea
calyptrata, 185.

Capulus
Braunt, 64.
calyptratus, 185.
ewomphaloides, 64.
haltotis, 64.
neritoides, sulcata, 64.
sulcatus, 64.

Centrifugus
planorhis, 122.

Chelodes, 48.
Bergmani, 51.
Gotlandicus, 52.

Conularia, 39.
aspersa, 46.
bilineata, 45.
cancellata, 42.
crenijgugata, 42.
curta, 42.
levis, 45.
monile, 44,
proteica, 42.
quadrisulcata, 42.
Sowerbit, 42.

K. Sv. Vet. Akad. Handl.

VET. AKADEMIENS HANDLINGAR.

INDEX.

Names printed in italics are synonyms.

Craspedostoma, 181.
brevispira, 183.
elegantulum, 183.
filistriatum, 183.
glabrum, 184.
involutum, 184.
spinulosum, 182.

Cyclonema, 174.
adstrictum, 178.
apicatum, 175.
brevispira, 67.
cancellatum, 175.
carinatum, 178.
delicatulum, 174.
distans, 176.
giganteum, 180.
glabrum, 179.
multicarinatum, 179.
nodulosum, 179.
octavia, 178.
perversum, 180.
striatum, 176.
tenuissimum, 180.
zonatum, 178.

Cyrtolites, 81.
arrosus, 83.
discus, 84.
euryomphalus, 84.
lamellifer, 82.
obliquus, 84.
orbiculus, 85.
pharetra, 83.

Delphinula
equilatera, 112.
alata, 116.
catenulata, 159.
cornu arietis, 158.
Sunata, 162.
Ssubsulcata, 161,

Euchrysalis, 195.
lineolata, 195.

Euomphalopterus
alatus, 117.

Euomphalus, 136.
equilaterus, 112.
alatus, 116.
Angelini, 138.
angulatus, 171.
angulosus, 159.
carinatus, 114.
catenulatus, 159.
centrifugus, 122.
cornu artetis, 158.
discors, 157.

Bd. 19. N:o 6.

BAND. 19. n:o 6. 249

Euomphalus
Junatus, 160, 162, 168.
Gotlandicus, 139.
gualieriatus, 108.
precursor, 140.
qualteriatus, 108.
rugosus, 159.
sculptus, 162.
substriatus, 122.
subsulcatus, 161.
supraangulatus, 171.
triquetrus, 140.
tuba, 140.
Walmstedti, 141.
Flemingia
elliptica, 104.
Helicites
equilaterus, 111.
angulatus, 171.
catenulatus, 159.
centriyugus, 122.
qualteriatus, 108.
supraangulatus, 171.
supragranulatus, 171
Holopea, 187.
applanata, 188.
nitidissima, 188.
nux, 187.
perforata, 188.
transversa, 188.
Holopella, 189.
minuta, 190.
regularis, 190.
teres, 190.
Inachus
angulatus, 171.
sulcatus, 122.
Litorina
octavia, 178.
Loxonema, 141.
attenuatum, 143.
fasciatum, 144.
intumescens, 143.
sinnosum, 142.
strangulatum, 144.
Macrochilina, 190.
bulimina, 191.
eancellata, 191.
fenestrata, 192.
Murchisonia, 125.
attenuata, 130.
bicineta, 106.
eancellata, 133.
cava, 128.

32

250 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND.

Murchisonia
cingulata, 127.
cochleata, 134.
compressa, 129.
crispa, 131.
deflexa, 134.
imbricata, 133.
Liloydti, 101.
moniliformis, 128.
munda, 132.
obtusangula, 128.
paradoxa, 131.
subplicata, 129.
tortuosa, 132.

Natica
glaucinoides, 64.
pared, 64.
subparva, 64.
Wenlockensis, 67.

Naticopsis
parva, 64,

Nerita
haliotis, 64.
prototypa, 67.
spirata, 67.

Ophileta
Ottawensis, 108.

Onychochilus, 196,
cochleatum, 197.
physa, 196.
reticulatum, 196.

Oriostoma,. 156.
acutum, 166.
alatum, 171.
angulatum, 171.
angulifer, 167.
contrarium, 160,
coronatum, 164.
discors, 157.
dispar, 173.
globosum, 160.
helicinum, 170.
lineatum, 173.
nitidissimum, 173.
Roemeri, 168.
rugosum, 159.
sculptum, 162.
Wisbyense, 167.

Paleacmea, 58.
solarium, 59.

Pileopsis
cornuta, 63.
sulcata, 63.
vetustis (vetustatis), 64.

Platyceras, 59.
cornutum, 63.
cyathinum, 69.
disciforme, 68.
enorme, 69.
loricatum, 67.
prototypum, 67.

Platyschisma?
helicites, 154.

Platystoma
niagarensis (=e), 64,

Pleurotomaria, 89.
equilatera, 111.

Pleurotomaria,
alata, 116.
angulata, 106.
antiquissima, 104.
balteata, 113.
bicincta, 106.
biformis, 98.
cirrhosa, 121.
claustrata, 97.
comata, 111.
dolium, 102.
elliptica, 104.
exquisita, 125.
frenata, 120.
glandiformis, 98.
gradata, 96.
helicina, 124.
Hindei, 99.
Holmi, 100.
labrosa, 113.
levissima, 104.
laqueata, 102.
latefusciata, 106.
latezonata, 99.
lenticularis, 108.
limata, 114.
Linnarssoni, 96.
Lioydi, 101.
Marklini, 121.
occidens, 113.
opposita, 119.
Othemensis, 111.
planorbis, 122.
pretexta, 119.
qualteriata, 108.
replicata, 116.
robusta, 103.
scutulata, 95.
subcarinata, 118.
subconica, 104.
togata, 119.
tubulosa, 103.
undulans, 120:
valida, 110.
voluta, 97.
Wisbyensis, 100.
Polytropis
discors, 150.
Pycnomphalus, 153.
acutus, 154.
obesus, 153.
trochiformis, 154.
Rhaphistoma
qualteriatum, 108.

' Skenea

funata, 161.
Solartum
petropolitanwm, 108.
Straparollus
equilaterus, 112.
alatus, 117.
angulatus, 171.
carinatus, 114.
catenulatus, 159.
discors, 158.

pseudoqualteriatus, 108.

qualterianus, 108.

Straparollus
rugosus, 159,
subsulcatus, 161.
sulcatus, 122.

Strophastylus

cyclostoma, 67.

Subulites, 193.
attenuatus, 194.
brevis, 194.
curyus, 194.
ventricosus, 193.

Terebra
sinuosa, 127, 142.

Tremanotus, 85.
compressus, 87.
longitudinalis, 86.

Trochilites
globosus, 160.

Trochita
calyptrata, 185.

Trochonema, 180.
fatwa, 106.
muricatum, 181.
rectilatera, 106.
turritum, 181.

Trochus, 145.
astraliiformis, 153.
cayus, 149.

Dalli, 150.
densestriatus, 152.
ellipticus, 104.
fulminatus, 147.
Gotlandicus, 146.
gyrans, 152.
incisus, 151.
Kolmodini, 150.
lamellosus, 151.
Lundgreni, 149.
mollis, 147.
profundus, 148.
Stuxbergi, 147.
undulans, 148.
Wisbyensis, 150.

Tryblidium, 52.
radiatum, 58.
reticulatum, 55.
unguis, 56.

Turbinites
alatus, 116.
centrifugus, 122.
cornu arietis, 158.

Turbo
alatus, 116.
antiquissimus, 104.
carinatus, 178.
cornu arictis, 158.
ellipticus, 104.
junatus, 161,
Leda, 176.
momus, 1638.
octavia, 178.
striatus, 176.

Turritella
attenuata, 130.
cingulata, 127.

Valuata
sulcata, 160.

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