PALAONTOGRAPHICAL SOCIETY.
VOL eX I,
FOSSIL FISHES OF THE ENGLISH CHALK.
Part IV.
Paces 129—-152; Puates XX VII—XXXII.
ILLUSTRATIONS OF TYPE SPECIMENS OF
INFERIOR OOLITE AMMONITES.
Prares I—VII; Tirnn-pace.
THE CRETACKOUS LAMELLIBRANCHIA.
Vou. DR Pari V.
Paces 181—216; Pirates XXVITI—XXXIV.
THE BRITISH FOSSIL ECHINODERMATA.
Vou. U, Parr Vv.
Paces 133—188; TrrtLE-Pace AND INDEX.
THE BRITISH CAMBRIAN TRILOBITES.
Part If.
Paces 49—64; Prats V, VI.
DCIS: Gan AP Ose Pais:
Part VII.
Paces exxi—exlviii, 273—358; Puatzs XX XII—XXXV.
IssuepD For 1908.
California Academy of Sciences
RECEIVED BY PURCHASE
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7 » &©XV. Issued June,
Supplement to the Fossil Corals, Part III (Oolitic), by Prof. Duncan (pp. 1—24, pls.
i—vii), with an Index to the Tertiary and Secondary Species.
On The Fossil Echinodermata, Cretaceous, Vol. I, Part V, by Dr. Wright (pp. 161—184,
» XXVI, Issued Oct., 1872, ple: xI—=xliv),
for the Year 1872) mye Fossil Merostomata, Part IV (Stylonurus, Eurypterus, Hemiaspis), by Mr. H.
Woodward (pp. 121—180, pls. xxi—xxx).
The Fossil Trigonie, No. I, by Dr. Lycett (pp. 1—52, pls. i—1x).
bo
CATALOGUE OF VOLUMES—Continued.
The Fossil Echinodermata, Cretaceous, Vol. I, Part VI, by Dr. Wright (pp. 185—224,
pls. xlv—lii). ;
Supplement to the Fossil Brachiopoda, Vol. IV, Part I (Tertiary and Cretaceous), by
Mx. Davidson (pp. 1—72, pls. 1—viii). f
Supplement to the Crag Mollusca, Part II (Bivalves), by Mr. S. V. Wood (pp. 99—231,
Vol. XX VII. Issued Feb., 1874, | pls. viii—xi, and add. plate).
for the Year 1873 | Supplement to the Reptilia of the Wealden (Iguanodon), No. V, by Prof. Owen
(pp. 1—18, pls. i, 11).
Supplement to the Reptilia of the Wealden (Hylwochampsa), No. VI, by Prof. Owen
(pp. 1—7).
The Fossil Reptilia of the Mesozoic Formations, Part I, by Prof. Owen (pp. 1—l4,
pls. 1, 11).
The Post-Tertiary Entomostraca, by Mr. G. 8. Brady, Rev. H. W. Crosskey, and Mr.
wy cians . 19" D. Robertson (pp. i—v, 1—232, pls. i—xvi).
ey Ut eae The Carboniferous Entomostraca, Part I (Cypridinide), by Prof. T. Rupert Jones
ibe tae | and Messrs. J. W. Kirkby and G. 8. Brady (pp. 1—56, pls. i—yv).
The Fossil Trigonie, No. Il, by Dr. Lycett (pp. 53—92, pls. x—xix).
The Flora of the Carboniferous Strata, Part IV, by Mr. EH. W. Binney (pp. 97—147,
pls. xix—xxiv).
ERIK, Issued Dec. 1875., The abe arte uae Cretaceous, Vol. I, Part VII, by Dr. Wright (pp. 225—264,
. > aay 1875 sel a :
for the Year 1875 The Fossil Trigonie, No. III, by Dr. Lycett (pp. 93—148, pls. xx—xxvii).
The Fossil Reptilia of the Mesozoic Formations, Part II, by Prof. Owen (pp. 15—94,
pls. i1i—xxii).
The Carboniferous and Permian Foraminifera (the genus Fusulina excepted), by Mr.
H. B. Brady (pp. 1—166, pls. i—xii).
XXX. Issued Dee.,1876, | Supplement to the Fossil Brachiopoda, Vol. IV, Part II, No. 1 (Jurassic and Triassic),
for the Year 1876 by Mr. Davidson (pp. 73—144, pls. ix—xvi).
Supplement to the Reptilia of the Wealden (Poikilopleuron and Chondrosteosaurus),
No. VU, by Prof. Owen (pp. 1—7, pls. i—vi).
Supplement to the Eocene Mollusca (Bivalves), by Mr. 8. V. Wood, 2 plates.
The Fossil Trigonixw, No. IV, by Dr. Lycett (pp. 149—204, pls. xxvili—xl).
The Hocene Mollusea (Univalves), Part IV, by Mr. S. V. Wood (pp. 8331—361, pl. xxxiv).
XXXI. Issued Feb ,1877, | The Carboniferous Ganoid Fishes, Part I (Palwoniscide), by Dr. Traquair (pp. 1—60,
for the Year 1877 pls. i—vil).
| The Fossil Reptilia of the Mesozoic Formations, Part III, by Prof. Owen (pp. 95—97,
pls. xxiii, xxiv).
The Fossil Elephants (E. antiquus), Part I, by Prof. Leith Adams (pp. 1—68, pls. i—v).
The Fossil Echinodermata, Cretaceous, Vol. I, Part VIII, by Dr. Wright (pp. 265—3800,
pls. lxii A, lxili—] xix).
Index and Title Page to the Fossil Echinodermata, Oolitic, Vol. I (Echinoidea), by Dr.
Wright (pp. 469—481).
The Fossil Merostomata, Part V (Neolimulus, &c.), by Dr. H. Woodward (pp. 181—2638,
: pls. xxxi—xxxvi, and title-page). 4nd
| XXXII. Issued Mar.,1878, pupplemey to the Fossil Brachiopoda; Viol: IV, Part II, No. 2 (Jurassic and Triassic),
for the Year 1878 _ by Mr. Davidson (pp. 145—242, pls. xvii—xxix). a:
The Lias Ammonites, Part I, by Dr. Wright (pp. 1—48, pls. i—viii).
The Sirenoid and Crossopterygian Ganoids, Part I, by Prof. Miall (pp. 1—82, pls.i, 14,
u—v).
Supplement to the Reptilia of the Wealden (Goniopholis, Petrosuchus, and Suche-
saurus), No. VIII, by Prof.,Owen (pp. 1—15, pls. i—vi).
The Pleistocene Mammalia, Part A (Preliminary Treatise), by Prof. Boyd Dawkins
(pp. i—xxxvili).
23
CATALOGUE OF VOLUMES—Continued.
The Kocene Flora, Vol. I, Part I, by Mr. J. S. Gardner and Baron Ettingshausen (pp.
1—38, pls. i—v).
Second Supplement to the Crag Mollusca (Univalves and Bivalves), by Mr. S. V. Wood
(pp. 1, 11, 1—58, pls. i—vi, and title-page).
Vol. XX XIIT. Issued May,1879, } The Fossil Trigoniv, No. V, by Dr. Lycett (pp. 205—245, pl. xli, and title-page).
for the Year 1879 | The Lias Ammonites, Part I, by Dr. Wright (pp. 49—164, pls. ix—xviii).
Supplement to the Reptilia of the Wealden (Goniopholis, Brachydectes, Nannosuchus,
Theriosuchus, and Nuthetes), No. IX, by Prof. Owen (pp. 1—19, pls. i—iv).
The Fossil Elephants (EH. primigenius), Part II, by Prof. Leith Adams (pp. 69 —146,
\ pls. vi—xy). ;
The Eocene Flora, Vol. I, Part I, by Mr. J. S. Gardner and Baron Ettingshausen
(pp. 39—5S, pls. vi—xi).
The Fossil Kehinodermata, Oolitic, Vol. II, Part IIL (Asteroidea and Ophiuroidea),
hee by Dr. Wright (pp. 155—203, pls. xix—xxi, pp. i—iv, and title-page).
a Be lecned ee { Supplement to the Fossil Brachiopoda, Vol. LV, Part ILI (Permian and Carboniferous),
ie by Mr. Davidson (pp. 243—316, pls. xxx—xxxvii).
The Lias Ammonites, Part IIT, by Dr. Wright (pp. 165 —261, pls. xix—xl).
The Reptilia of the London Clay, Vol. II, Part I (Chelone), by Prof. Owen (pp. 1—4,
\ pls. 5, 28)
pls. Ixx—Ixxv).
Supplement to the Fossil Brachiopoda, Vol. IV, Part IV (Devonian and Silurian,
from Budleigh-Salterton Pebble Bed), by Mr. Davidson (pp. 317—358, pls.
XXXvill—xlii).
The Fossil Trigonie (Supplement No. 1), by Dr. Lycett (pp. 1—4).
The Lias Ammonites, Part IV, by Dr. Wright (pp. 265—328, pls. xxii A, xxiis,
xli—xlviil).
The Reptilia of the Liassic Formations, Part III, by Prof. Owen (pp. 83—134, pls.
XXi—xxxill, and title-page).
The Fossil Elephants (EK. primigenius and EH. meridionalis), Part III, by Prof. Leith
Adams (pp. 147—265, pls. xvi—xxvili, and title-page).
» XXXYV. Issued May.1881,
| The Fossil Echinodermata, Cretaceous, Vol. I, Part IX, by Dr. Wright (pp. 301—324,
for the Year 188] |
The Eocene Flora, Vol. I, Part III, by Mr. J. 8. Gardner and Baron Ettingshausen
(pp. 59—86, pls. xu, xiil, and title-page).
Third Supplement to the Crag Mollusea, by the late Mr. 8. V. Wood (pp. 1—24, pl. i).
The Fossil Hehinodermata, Cret., Vol. I, Part X, by Dr. Wright (pp. 325—371, pls.
Ixxvi—lIxxx, and title-page).
Supplement to the Fossil Brachiopoda, Yol. LV, Part V, by Dr. Davidson (pp. 369—383,
and title-page).
Do., Vol. V, Part I (Devonian and Silurian), by Dr. Davidson (pp. 1—134, pls.
1—Vil).
The Lias Ammonites, Part V, by Dr. Wright (pp. 329—400, pls. xlix—lii, lit a,
liii—lIxix).
» XXXVI. Issued June,1882,
; for the Year 1882
The Trilobites of the Silurian, Devonian, &c., Formations, Part V, by the late Mr. J. W.
Salter (pp. 215—224, and title-page).
The Carboniferous Trilobites, Part I, by Dr. H. Woodward (pp. 1—38, pls. i—vi).
Supplement to the Fossil Brachiopoda, Vol. V, Part If (Silurian), by Dr. Davidson
(pp. 185—242, pls. vilimxvii).
The Fossil [rigoniz (Supplement No. 2), by the late Dr. Lycett (pp. 5—19, pls. i—iv
and title-page).
The Lias Ammonites, Part VI, by Dr. Wright (pp. 401—440, pls. 1xx—Ixxvii).
» XXXVII. Issued Oct.,1883,
for the Year 1883
The Eocene Flora, Vol. II, Part II, by Mr. J. S. Gardner (pp. 61—90, pls. x—xx),
The Carboniferous Entomostraca, Part I, No. 2, by Prof. I. Rupert Jones, Mr. J. W.
Kirkby, and Prof. G. 8. Brady (pp. i—iil, 57—92, pls. vi, vil, and title-page). —
The Carboniferous Trilobites, Part Il, by Dr. H. Woodward (pp. 39—S6, pls.,vii—x,
and title-page).
Supplement to the Fossil Brachiopoda, Vol. V, Part IIL, by Dr. Davidson (pp. 243—176,
pls. xviii—xxi, and title-page).
The Lias Ammonites, Part VII, by Dr. Wright (pp. 441—480, pls. Ixxvili—lxxxvi).
» XXX VIII. Issued Dec.,1884,
| The Eocene Flora, Vol. II, Part I, by Mr. J. S. Gardner (pp. 1—60, pls. i—ix).
for the Year 1884. |
24
CATALOGUE OF VOLUMES—Continued.
The Eocene Flora, Vol. II, Part III, by Mr. J. S. Gardner (pp. 91—159, pls.
XX1—xxvii, and title-page).
The Stromatoporoids, Part I, by Prof. Alleyne Nicholson (pp. i—iii, 1—130, pls. i—xi).
The Fossil Brachiopoda (Bibliography), Vol. VI (pp. 1—163), by the late Dr. Davidson
and Mr. W. H. Dalton.
The Lias Ammonites, Part VIII, by the late Dr. Wright (pp. 481—5038, pl. Ixxxviii, and
title-page).
Vol. XXXIX. Issued Jan., 1886.
for the Year 1885 |
la
The Morphology and Histology of Stigmaria Ficoides, by Prof. W. C. Williamson
(pp. i—iv, 1—62, pls. i—xv).
The Fossil Sponges, Part I, by Dr. G. J. Hinde (pp. 1—92, pls. i—viii).
The Jurassic Gasteropoda, Part I, No. 1, by Mr. W. H. Hudleston (pp. 1—56).
The Inferior Oolite Ammonites, Part I, by Mr. 8. S. Buckman (pp. 1—24, pls. i—vi).
The Pleistocene Mammalia, Part VI, by Prof. Boyd Dawkins (pp. 1—29, pls. i—vii).
XL. Issued Mar.,1$87,_
for the Year 1886
”
The Paleozoic Phylopoda, Part I, by Prof. T. R. Jones and Dr. Woodward (pp. 1—72,
pls. 1—x11).
| The Fossil Sponges, Part II, by Dr. G. J. Hinde (pp. 983—188, pl. ix).
, The Jurassic Gasteropoda, Part I, No. 2, by Mr. W. H. Hudleston (pp. 57—136, pls.
ss X LI. Issued Jan., 1888,
for the Year 1887
1—Vvl).
The Inferior Oolite Ammonites, Part II, by Mr. S. S. Buckman (pp. 25—56, pls.
Vii—xiv).
XIX).
The Tertiary Entomostraca (Supplement), by Prof. T. Rupert Jones and Mr. C. D.
Sherborn (pp. 1—455, pls. i—iii).
The Jurassic Gasteropoda, Part I, No. 3, by Mr. W. H. Hudleston (pp. 187—192, pls.
Vil—x1).
SUM ested Nats lbee, The Inferior Oolite Ammonites, Part III, by Mr. 8. 8. Buckman (pp. 57—144, pls. xv,
for the Year 1888 © Sea)
The Devonian Fauna of the South of England, Part I, by the Rev. G. F. Whidborne
(pp. i, 1, 1—46, pls. i—iv).
Title-pages and Prefaces to the Monographs on the Reptilia of the Wealden and
Purbeck (Supplements), Kimmeridge Clay, and Mesozoic Formations, and
e Stromatoporoids, Part II, by Prof. Alleyne Nicholson (pp. 131—158, pls. xii—
| on the Cetacea of the Red Crag.
The Cretaceous Entomostraca (Supplement), by Prof. T. Rupert Jones and Dr. G. J,
Hinde (pp. i—viii, 1—70, pls. i—iv).
The Jurassic Gasteropoda, Part I, No. 4, by Mr. W. H. Hudleston (pp. 195—224, pls.
Xli—XvV1).
The Inferior Oolite Ammonites, Part IV, by Mr. 8.5. Buckman (pp. 145—224, pls.
XXiV—XXXVI).
The Devonian Fauna of the South of England, Part II, by the Rev. G. F. Whidborne
(pp. 47—154, pls. v—vili, vill A, 1x—xv).
XLII. Issued Mar., 1890,
for the Year 1889 ~
The Stromatoporoids, Part III, by Prof. Alleyne Nichoison (pp. 159—202, pls. xx—xxv).
The Fossil Echinodermata, Cretaceous, Vol. II, Part I (Asteroidea), by Mr. W. Perey
Sladen (pp. 1—28, pis. i—viii).
, XLIV. Issued Apr.,1891, |} The Inferior Oolite Ammonites, Part V, by Mr. 8. 8. Buckman (pp. 225—256, pls.
for the Year 1890 XXXVii—xliv),
The Devonian Fauna of the South of England, Part III, by the Rev. G. F. Wiidborne
(pp. 155—250, pls. xvi—xxiv).
Title-pages to the Supplement to the Fossil Corals, by Prof. Duncan.
The Jurassic Gasteropoda, Part I, No. 5, by Mr. W. H. Hudleston (pp. 225—272, pls.
XVlI—xx).
The Inferior Oolite Ammonites, Part VI, by Mr. 8.8. Buckman (pp. 257—312, pls.
3 XLY. Issued Feb., 1892. xlv—lvi).
for the Year 1891) The Devonian Fauna of the South of England, Part IV (Conclusion of Vol. I)
(pp. 251—3544, pls. xxv—xxx1, and title-page).
Vol. II, Part I, by the Rev. G. F. Whidborne (pp. 1—56, pls. i
el)
bo
Or
CATALOGUE OF VOLUMES—Continued.
The Stromatoporoids, Part IV (Conclusion), by Prof. Alleyne Nicholson (pp. 2083—
234, pls. xxvi—xxix, and title-page).
The Paleozoic Phyllopoda, Part II, by Prof. T. R. Jones and Dr. Woodward (pp. 73—
124, pls. x11i—xvil).
Vol. XLVI. Issued Nov.,1892, | 'The Jurassic Gasteropoda, Part I, No. 6, by Mr. W. H. Hudleston (pp. 273—324, pls.
for the Year 1892 ° XXI1—xxvi).
313—344, pls.
» XLVII. Issued Dec., 1893,
The Inferior Oolite Ammonites, Part VII, by Mr. S. 8. Buckman (pp.
lvii—lxxvi).
The Devonian Fauna of the South of England, Vol. II, Part II, by the Rev. G. F.
Whidborne (pp. 57—88, pls. vi—x).
The Fossil Sponges, Part III, by Dr. G. J. Hinde (pp. 189—254, pls. x—xix).
The Fossil Echinodermata, Cretaceous, Vol. II, Part II (Asteroidea), by Mr. W. Percy
Sladen (pp. 29—66, pls. ix—xvi).
The Inferior Oolite Ammonites, Part VIII, by Mr. 8. 8. Buckman (pp. 345—376, pls.
Ixxvli—xcii).
The Devonian Fauna of the South of England, Vol. II, Part III, by the Rev. G. F.
Whidborne (pp. 89—160, pls. xi—xvii).
for the Year 1893 |
The Jurassic Gasteropoda, Part I, No. 7, by Mr. W. H. Hudleston (pp. 325—890, pls.
XXV11—XxxXll).
perpen: Anthracomya, and Naiadites, Part I, by Dr. W. Hind (pp. 1—80, pls.
» XLVIII. Issued Nov., 1894,
”
XLIX. Issued Oct., 1895,
xCill—ciil)
The Fishes of the Old Red Sandstone, Part II, No. 1, by Dr. R. H. Traquair (pp. 63—
90, pls. xv—xviil).
The Crag Foraminifera, Part II, by Prof. T. R. Jones (pp. 73—210, pls. v—vii).
The Jurassic Gasteropoda, Part I, No. 8, by Mr. W. H. Hudleston (pp. 391—444, pls.
XXxii—x]).
for thie Year 189% Carbonicola, Anthracomya, and Naiadites, Part II, by Dr. W. Hind (pp. 81—170, pls.
Xli—xx).
xi).
for the Year sie The ialsvien Oolite Ammonites, Part IX, by Mr. S. S. Buckman (pp. 377—456, pls.
The Devonian Fauna of the South of England, Vol. II, Part IV, by the Rev. G. F.
Whidborne (pp. 161—212, pls. xviii—xxiv).
The Crag Foraminifera, Part III, by Prof. T. R. Jones (pp. 211—314).
The Jurassic Gasteropoda, Part I, No. 9, by Mr. W. H. Hudleston (pp. 445—514,
pls. xli—xliv, and title-page).
eaeponicoes Anthracomya, and Naiadites, Part III, by Dr. W. Hind (pp. 171—182,
pl. xxi, and title-page).
The Gaboutacts Lamellibranchiata, Part I, by Dv. W. Hind (pp. 1—80, pls. i, we
The Devonian Fauna of the South of England, Vol. III, Part 1, by the Rev. G.
Whidborne (pp. 1—112, pls. i—xvi).
L. Issued Oct., 1896,
for the Year 1896 ~
The Crag Foraminifera, Part IV, by Prof. T. R. Jones (pp. vii—xv, 315—402, and
title. page). sae
The Carboniferous Lamellibranchiata, Part II, by Dr. W. Hind (pp. 81—208, pls. ui
—Xv).
The Carboniferous Cephalopoda of Ireland, Part I, by Dr. A. H. Foord (pp. 1—22
pls. i—vii).
The Devonian Fauna of the South of England, Vol. III, Part II, by the Rev. G. F.
Whidborne (pp. 113—178, pls. xvii—xxi).
LI. Issued Dec., 1897,
|
|
|
|
|
The Beers Phyllopoda, Part III, by Prof. T. R. Jones and Dr. Woodward (pp. 125
176, pls. xvili—xxv).
The Carboniferous Lamellibranchiata, Part III, by Dr. W. Hind (pp. 209—276, pls.
XVI—XXvV).
The Inferior Oolite Ammonites, Part X, by Mr. 8. 8. Buckman (pp. i—xxxii, Suppl.
pls. i—1v).
The Caihoniferous Cephalopoda of Ireland, Part II, by Dr. A. H. Foord (pp. 23—48,
pls. viii—xvii).
The Devonian Fauna of the South of England, Vol. III, Part III, by the Rev. G. F.
Whidborne (pp. 179—256, pls. xxii—xxxviii),
d
LII. Issued Dec., 1898,
for the Year 1898
iw)
(oy)
CATALOGUE OF VOLUMES—Continued.
The Paleozoic Phyllopoda, Part IV, by Prof. T. R. Jones and Dr. Woodward
(pp. i—xv, 175, 176, 177—211, pls. xxvi—xxxi, and title-page).
The Cretaceous Lamellibranchia, Part I, by Mr. H. Woods (pp. 1—72, pls. i—xiv).
The Carboniferous Lamellibranchiata, Part IV, by Dr. W. Hind (pp. 277—360, pls.
XXVI—XXXIX).
The Inferior Oolite Ammonites, Part XI, by Mr. S.S. Buckman (pp. xxxiii—lxiv, pls.
vV—xXiv).
Vol. LIII. Issued Dec., 1899,
for the Year 1899
The Cretaceous Lamellibranchia, Part II, by Mr. H. Woods (pp. 73—112, pls. xv—xix).
The Carboniferous Lamellibranchiata, Part V, by Dr. W. Hind (pp. 361—476, pls. xl
—liy).
» LIV. Issued Dec., 1900, |. The Carboniferous Cephalopoda of Ireland, Part III, by Dr. A. H. Foord (pp. 49—126,
for the Year 1900 ~ pls. xvili—xxxil).
| The British Pleistocene Mammalia, Title-page for Vol. I, by Messrs. Dawkins and
Sanford.
The Structure of Carboniferous Plants, Title-page, by Mr. E. W. Binney.
The Cretaceous Lamellibranchia, Part III, by Mr. H. Woods (pp. 118—144, pls. xx—
XXV1).
The Carboniferous Lamellibranchiata, Vol. II, Part I, by Dr. W. Hind (pp. 1—34,
pls. i—vi), Title-page and Index for Vol. I.
» LV. Issued Dec., 1901, | The Carboniferous Cephalopoda of Ireland, Part IV, by Dr. A. H. Foord (pp. 127—
for the Year 1901 | 146, pls. xxxiil—xxxix).
British Graptolites, Part I, by Miss Elles and Miss Wood, edited by Prof. Lapworth
(pp. 1—54, pls. i—iv).
Ganoid Fishes of British Carboniferous Formations—Part I, Paleoniscide, No. 2,
by Dr. Ramsay H. Traquair (pp. 61—87, pls. viii—xviii).
The Cave Hyena, by Prof. S$. H. Reynolds (pp. 1—25, pls. i—xiv).
The Fishes of the English Chalk, Part I, by Dr. A. Smith Woodward (pp. 1—56, pls.
: i—xill).
» YI. Ieenoe pote Te - The Cretaceous Lamellibranchia, Part IV, by Mr. H. Woods (pp. 145—196, pls. xxvii
—XXXViil). ,
British Graptolites, Part I, No. 2,, by Miss Elles and Miss Wood, edited by Prof. Lap-
L worth (pp. i—xxviii, 55—94, pls. y—xiil).
The pe of the English Chalk, Part I, by Dr. A. Smith Woodward (pp. 57—96,
pls. xiv—xx).
The Cretaceous Lamellibranchia, Part V, by Mr. H. Woods (pp. i—xliii, 197—232,
pls. xxxix—xlii), Title-page and Index for Vol. I.
The Carboniferous Lamellibranchiata, Vol. II, Part II, by Dr. W. Hind (pp. 35—124,
,» LVII. Issued Dec., 1903, . pls. vii—xxi).
for the Year 1903 | The Carboniferous Cephalopoda of Ireland, Part V, by Dr. A. H. Foord (pp. 147—234,
pls. xl—xlix), Title-page and Index.
The Lower Paleozoic Trilobites of Girvan, Part I, by Mr. F. R. Cowper Reed (pp. 1—
48, pls. i—vi).
British Graptolites, Part III, by Miss Elles and Miss Wood, edited by Prof. Lapworth,
(pp. xxix—lii, 103—134, pls, xiv—xix).
The Fishes of the Old Red Sandstone, Part II, No. 2, by Dr. R. H. Traquair (pp.
91—118, pls. xix—xxvi).
The Cretaceous Lamellibranchia, Vol. II, Part I, by Mr. H. Woods (pp. 1—56, pls.
i—vlil).
The Carboniferous Lamellibranchiata, Vol. II, Part III, by Dr. W. Hind (pp. 125—
, UVIII. Issued Dec., 1904. - 216, pls. xxii—xxv).
for the Year 1904 | The pes Oolite Ammonites, Part XII, by Mr. S. 8. Buckman (pp. Ixv—elxviii,
Ss. XV—xXIx).
The Lower Paleozoic Trilobites of Girvan, Part II, by Mr. F. R. Cowper Reed
a (pp. 49—96, pls. vii—xiii).
British Graptolites, Part IV, by Miss Elles and Miss Wood, edited by Prof. Lapworth,
(pp. lii—lxxii, 1835—180, pls. xx—xxv).
CATALOGUE OF VOLUMES—Continued.
(pp. 67—90, pls. xvii—xxvi).
The Cee eus Lamellibranchia, Vol. II, Part Il, by Mr. H. Woods (pp. 57—96,
pls. vili—xi).
The Carboniferous Lamellibranchiata, Vol. II, Title-pages and Index, by Dr. W. Hind.
The Inferior Oolite Ammonites, Part XIII, by Mr. S. 8. Buckman (pp. elxix—ceviii,
pls. xx—xxiyv).
The Cornbrash Fauna, Part I, by the Rev. J. F. Blake (pp. 1—100, pls. i—ix).
Vol. LIX. Issued Nov., 1905,
[rs Fossil Echinodermata, Cretaceous, Vol. II, Part III, by Mr. W. K. Spencer
for the Year 1905 |
The Pleistocene Bears, by Prof. S. H. Reynolds (pp. 1—35, pls. i—viii).
The Fishes of the Old Red Sandstone, Part II, No. 3, by Dr. R. H. Traquair
(pp. 119—130, pls. xxvii—xxxi).
The Cretaceous Lamellibranchia, Vol. II, Part III, by Mr. H. Woods (pp. 97—132,
pls. x1ii—x1x).
The Lower Paleozoic Trilobites of Girvan, Part III, by Mr. F. R. Cowper Reed
(pp. 97—186, Title-page and Index, pls. xiv—xx).
The Cambrian Trilobites, Part I, by Mr. P. Lake (pp. 1—28, pls. i, ii).
British Graptolites, Part V, by Miss Elles and Miss Wood, edited by Prof, Lapworth
(pp. Ixxiii—xevi, 181—216, pls. xxvi, xxvii).
» LX. Issued Dec., 1906,
for the Year 1906
and Postscript).
Ganoid Fishes of British Carboniferous Formations, Part I, Paleoniscide, No. 3, by
Dr. R. H. Traquair (pp. 87—106, pls. xix—xxiii).
The Fishes of the English Chalk, Part III, by Dr. A. Smith Woodward (pp, 97—128,
pls. xxi—xxy)).
The Inferior Oolite Ammonites, Part XIV, by Mr. 8. 8. Buckman (pp. ecix—celxii,
Title-pages, Preface, and Index).
The Cretaceous Lamellibranchia, Vol. II, Part [V, by Mr. H. Woods (pp. 133—180,
pls. xx—xxvli).
The Fossil Echinodermata, Cretaceous, Vol. II, Part IV, by Mr. W. K. Spencer
(pp. 91—182, pls. xxvii—xxix).
The British Conulariz, by Miss Ida L. Slater (pp. 1—40, pls. i—v, Title-page and Index).
The Cambrian Trilobites, Part II, by Mr. P. Lake (pp. 29—48, pls. 11, iv).
British Graptolites, Part VI, by Miss Elles and Miss Wood (Mrs. Shakespear), edited
by Prof. Lapworth (pp. xevii—exx, 217—272, pls. xxvili—xxx1).
The Devonian Fauna of the South of England, Vol. IJ, Part V, and Vol. III, Part IV,
by the Rev. G. F. Whidborne (Vol. I, pp. 215—222, Title-page and Index ;
Vol. III, pp. 287—247, Title-page and Index).
The Cornbrash Fauna, Part II, by the Rev. J. F. Blake(pp. 101—102, Title-pageand Index).
,» UXI. Issued Dec., 1907,
for the Year 1907
The Fishes of the English Chalk, Part 1V, by Dr. A. Smith Woodward (pp. 129—152,
pls. xxvii—xxx11).
Illustrations of Type Specimens of Inferior Oolite Ammonites (pls. i—vii).
The Cretaceous Lamellibranchia, Vol. II, Part V, by Mr. H. Woods (pp. 181—216,
pls. Xxvili—xxxiv).
The Fossil Echinodermata, Cretaceous, Vol. II, Part V, by Mr. W. K. Spencer
(pp. 1883—138, Title-page and Index). :
The Cambrian Trilobites, Part III, by Mr. P. Lake (pp. 49—64, pls. v, vi.)
British Graptolites, Part VII, by Miss Elles and Miss Wood (Mrs. Shakespear), edited
by Prof. Lapworth (pp. exxi—exlviii, 273—358, pl. xxxii—xxxy).
, UXII. Issued Dec., 1908,
for the Year 1908
The Sirenoid Ganoids, Part II, by Prof. L. C. Miall (pp. 833—34, Title-page, Preface,
Palxontographical Society, 1908.
THE
Peo ls sal = fet Ss tik
OF THE
ENGLISH CHALK.
BY
ARTA SViItTe WOODWARD, LL.D., FBS
KEEPER OF THE DEPARTMENT OF GEOLOGY IN THE BRITISH MUSEUM; SECRETARY OF THE
PALHONTOGRAPHICAL SOCIETY.
PA Ve
Paces 129—152; Puates XX VII—XXXII.
LOD ON:
PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.
1908.
PRINTED BY ADLARD AND SON, LONDON AND DORKING.
PACHYRHIZODUS. i
iw)
We)
4, Pachyrhizodus subulidens (Owen). Plate XXVII; Text-figure 39.
1842. Raphiosaurus subulidens, R. Owen, Rep. Brit. Assoc., 1841, p. 190.
1842. Raphiosawrus, R. Owen, Trans. Geol. Soc. [2], vol. vi, p. 413, pl. xxxix, fig. 3.
1850. Raphiosaurus lucius, R. Owen, in Dixon, Geol. Sussex, p. 385, pl. xxxix, figs. 1—3.
1851. Raphiosawrus subulidens, R. Owen, Rept. Cret. Form. (Mon. Paleont. Soc.), p. 19, pl. x, figs.
5, 6.
1889. Pachyrhizodus subulidens, A. 8S. Woodward, Ann. Mag. Nat. Hist. [6], vol. iv, p. 351.
1901. Pachyrhizodus subulidens, A. S. Woodward, Catal. Foss. Fishes B. M., pt. iv, p. 43, pl. vii,
figs. 1, 2.
Type.—Anterior portion of maxilla; Sedgwick (Woodwardian) Museum, Cam-
bridge.
Specific Characters.—A small species, the maxilla attaiming a length of about
10 em., the mandible about 15 cm. All teeth slender, very smooth, with the apex
imwardly and backwardly curved. Manilla flattened externally, with sockets for
from 30 to 40 teeth ; premaxilla expanded into a triangular facial lamina. Dentary
bone very deep, but rapidly contracting in front into a narrow thickened sym-
physis; its outer face remarkably smooth, marked with two deep longitudinal
depressions between which the middle part of the bone projects in a rounded
longitudinal ridge; its total number of tooth-sockets not less than 30.
Description of Specimens.—The type specimen (Pl. XX VII, fig. 2), which is the
anterior part of a left maxilla, was originally described by Owen as the dentary
bone of a lizard. A similar maxilla of the right side has been found in association
with part of a dentary (B. M. no. 38566), thus identifying the latter element ;
while another maxilla is associated with a clavicle and scales. These specimens
prove that the head represented in P]. XX VII, fig. 1, belongs to the same species.
In the latter fossil the cranium lacks the ethmoidal region and is incomplete
behind on the right side, but it exhibits its principal characters when viewed from
above (fig. 1 a). The external bones are nearly smooth, marked only in part by
the radiating structural lines, which are most conspicuous in the depressed middle
area of the frontal region. The supraoccipital (socc.) is exposed in a short and
broad band at the back of the cranial roof, and bears a large median vertical crest
on its hinder face. The epiotic (epo.) is also partially seen from above, forming a
prominent angle. The parietal (pa.) is a small nearly square bone at the postero-
external border of the frontal, widely separated from its fellow of the opposite side.
The squamosal (sq.) is larger, but its precise shape and extent are not shown.
Judging by appearances in the fracture on the right side, the parietal and
squamosal join the hinder part of the frontal in forming the roof of an extensive
posterior temporal fossa. The frontal bones ( fr.) are especially large, and their
shape and contour are well shown in fig. la. They are constricted above the
ik¢
130 FOSSIL FISHES OF THE ENGLISH CHALK.
hinder part of the eye, where their outer portion appears to be fused with the
downwardly tapering postfrontal or sphenotic (pif.). The cheek (fig. 1) 1s com-
pletely covered with thin plates, and the rather small eye has an ossified sclerotic.
The postorbital plates (o.), three or four in number, are much elongated antero-
posteriorly, and are traversed near the orbital border by the usual sensory canal,
which is filled in the fossil with oxide of iron. There is a narrow suborbital plate
(or series of plates), also traversed by the sensory canal (so.) ; and there is a short
and deep antorbital (ao.), which appears to be thicker and less flattened than the
others. A narrow plate which tapers to a point in front, slightly overlaps the
hinder part of the maxilla and may probably be regarded as a supramaxilla.
The characteristic maxilla (mv.), with its flattened outer face and nearly straight
oral border, is also well seen, though imperfect behind and shghtly overlapped
above by the cheek-plates. Its long and stout antero-imternal process is exposed by
Fic. 39.—Pachyrhizodus subulidens (Owen); restored drawing of head, left lateral and upper
aspects, about one half natural size—HEnglish Chalk. ag., angular; ao., antorbital; d., dentary ;
epo., epiotic; eth., mesethmoid; /7., frontal; ma., maxilla; orb., orbit; pa., parietal; pm., pre-
maxilla; po., postorbitals; qu.,quadrate ; smax.,supramaxilla; so.,suborbital; socc., supraoccipital ;
sq., Squamosal ; #., upper cheek-plate.
the accidental removal of the premaxilla. Its inner side is shown by another
specimen (Pl. XXVII, fig. 3), im which the slender and slightly curved teeth are
clearly flanked outside by a low thin wall of bone. Remains of the premaxilla
occur in front of the maxilla just mentioned, showing the bases of the usual two large
inner teeth, and suggesting that the bone was expanded into a deep lamina which
occupied more of the face than the premaxilla in the preceding three species. The
mandible occurs in position in the head already described (Pl. XXVII, figs. 1, 1 0),
but it is so much fractured that the characters of the dentary are better shown in
the original of Pl. XXVII, fig. 3a. The symphysis tapers and is much thickened,
but does not bear any teeth within the outer series. The outer face of the bone is
remarkably smooth, and the longitudinal bulging of its middle portion is especially
well seen in the right ramus (fig. 3 7), which is complete below. The teeth are very
large compared with those of the maxilla, and their polished crowns curve backwards
and inwards. Of the opercular apparatus it can only be said that the preoper-
culum (Pl. XXVII, fig. 1, pop.) is much expanded at the angle and apparently
PACHYRHIZODUS. 131
smooth. Nine or ten broad branchiostegal rays (bi.) are fixed to the epihyal (fig.
1b, eph.), while traces of those fixed to the ceratohyal show that they must have
been numerous. It is not known whether a gular plate was present or absent.
The lower segments of the two halves of one branchial arch are fused with their
basibranchial bone (0.a.).
The vertebral centra appear to exhibit a greater tendency towards slight
pitting of the sides than those of the typical species.
The clavicle is characterised by a very wide inwardly-directed expansion (PI.
XXVIII, fig. 1c); and to its posterior border is appended a large postclavicular
scale above the base of the pectoral fin.
A few thin scales associated with the maxilla shown in Pl. XXVII, fig. 3, are
ornamented in their exposed sector with a very fine granulation and a few shallow
and discontinuous radiating grooves (Pl. XXVII, fig. 4). Their extensive
overlapped portion is smooth, without any radiating grooves.
Remarks.—This species is intermediate between the typical Pachyrhizodus and
the typical Thrissopater ; and it now seems probable that the occipital part of a
small skull which I once referred to “ Thrissopater magnus” (Catal. Foss. Fishes B. M.,
pt. iv, 1901, p. 35, pl. v, fig. 2) should be assigned to Pachyrhizodus subulidens.
Horizon and Localities—Zone of Holaster subglobosus : Cherry Hinton,
Cambridgeshire ; Burham and Halling, Kent. Zone of Schloenbachia varians :
Barton, Cambridgeshire.
5. Pachyrhizodus (?) magnus, A. 8. Woodward. Plate XXVIII, fig. 1.
1901. Thrissopater magnus, A. 8. Woodward, Catal. Foss. Fishes B. M., pt. iv, p. 34, pl. v, fig. 1.
Type.—Imperfect head, probably from the zone of Holaster subglobosus ; British
Museum.
Specific Characters.—A species of uncertain generic position, apparently con-
nected with Pachyrhizodus by P. subulidens, which is intermediate between this
and the typical species. Length of maxilla about 7°5 cm., of mandible about
11 cm.; both these bones and the premaxilla resembling those of P. subulidens.
Teeth unusually small, but of the characteristic shape and implantation. Median
depression of cranial roof deep behind, but differing from that of the typical skull
of Pachyrhizodus in not extending further forwards than the transverse ridge
between the orbits.
Description of Specimen.—Vhis species appears to be known only by the type
specimen (Pl. XXVIII, fig. 1), which is vertically crushed so that the cheeks are
displaced outwards, while the antorbital region is “ faulted”? by an oblique trans-
verse fracture.
The most characteristic feature of the cranial roof is the median depression i
182 FOSSIL FISHES OF THE ENGLISH CHALK.
the hinder frontal region, where the bone becomes comparatively smooth. The
small, finely punctate supraoccipital (socc.) is observable at the hinder border of
the depression, while quite posteriorly, on the left side, the epiotic (epo.) 1s crushed
outwards. The limits of the parietal (pa.), squamosal (sq.), and frontal (/r-)
elements can also be distinguished. The frontals are very large as usual, and
exhibit a longitudinal series of pits along either side of the depression, marking
the course of the slime-canal. The terminal mesethmoid (eth.), finely punctate
like the supraoccipital, is relatively small and pointed in front, without any
expansion. The postorbital cheek-plates (po.), apparently three in number, are
large and antero-posteriorly elongated, marked in their hinder portion with shghtly
-adiating furrows, and traversed near the orbital border with the usual shme-canal.
There is a long and narrow suborbital plate (so.), shghtly excavated at its orbital
border, nearly straight-edged below. The antorbital plate (ao.), which is broken
by the fracture on the left side, but nearly complete on the right, is remarkably
large, deep, and narrow. It is expanded into a triangular plate below, somewhat
twisted about an oblique ridge at its middle, and then shghtly expanded again at
the upper end, where it forms part of the upper border of the orbit, and meets
another plate in an oblique suture. The latter plate (w.) forms a small part of the
orbital border, and tapers backwards while separating at least the anterior half of
the upper postorbital from the edge of the cranial roof. A corresponding plate
occurs in the existing Mops (Text-fig. 35, p. 112).
The premaxilla (pme.), when viewed from the outer face, is triangular in shape,
with a sharp notch in its short posterior border. It meets its fellow of the
opposite side in front of the pointed mesethmoid. There are at least 15 tooth-
sockets in its marginal series; and one larger tooth can be seen within on the
comparatively small palatal extension of the bone. The maxilla (m.) has
a flattened and nearly smooth outer face, bevelled at the oral border, which
exhibits many of the relatively small teeth. Throughout its hinder half it is over-
lapped by the single supramaxilla (sina.), which is also smooth, tapering in front
and ending in a rounded expansion behind. The dentary bone of the mandible (d.)
closely resembles that of P. subulidens, but bears only very small teeth. The
articulo-angular bone (ag.), as usual, is quite short, and the articular facette for
the quadrate (qu.) is on its lowest hinder portion.
Horizon and Locality.—Probably zone of Holaster subglobosus: Hollingbourn,
Kent.
Genus ELOPOPSIS, Heckel.
Hlopopsis, J. J. Heckel, Denkschr. k. Akad. Wiss., math.-naturw. Cl., vol. xi, 1856, p. 251.
Generic Characters.—Skull as in Pachyrhizodus. Teeth solid, robust, and
conical, usually more or less laterally compressed, and enamelled nearly to the
KLOPOPSIS. 133
base, where they are fused with the supporting bone; mandible with a single
close series and an inner pair of relatively large teeth at the symphysis; pre-
maxilla somewhat horizontally extended, bearing one or two relatively large teeth
within the marginal series of very small teeth; maxilla robust, not much arched,
with a single series of teeth which are smaller than those of the mandible.
Vertebree between 50 and 60 in number, the centra not longer than deep, all
shghtly constricted and marked with longitudinal ridges. Pelvic fins opposed
to the dorsal; caudal fin forked. Scales large and delicate, deeply overlapping,
their exposed portion smooth or marked only with shght longitudinal strize or
small shallow pittings.
Type Species.—Hlopopsis fenzli (Heckel, loc. cit., 1856, p. 251, pl. xii, fig. 1),
represented by a nearly complete fish im the Royal Court Museum, Vienna, from
the Cretaceous (supposed Urgonian) of Comen, Istria.
Remarks.—The original specimens of this genus from Comen are crushed in
fissile rock, and do not exhibit much of their cranial structure. More fragmentary
specimens from the Chalk of Bohemia," Westphalha,’ and HKngland display parts of
the skull and jaws, with the dentition.
4.
1. Elopopsis crassus (Dixon). Plate XXVIII, figs. 2
1850. Osmeroides crassus, F. Dixon, Geol. Sussex, p. 376.
1888. Osmeroides crassus, A. S. Woodward, Proc. Geol. Assoc., vol. x, p. 322.
1895. Elopopsis crassus, A. S. Woodward, Proc. Zool. Soc., 1894, p. 659, pl. xl, fig. 1.
1901. Elopopsis crassus, A. 8S. Woodward, Catal. Foss. Fishes B. M., pt. iv, p. 10.
1907. Hlopopsis crassus, A. 8. Woodward, The Naturalist, p. 306.
T'ype.—Imperfect head; Brighton Museum.
Specific Characters.—An imperfectly known large species, the mandible attain-
ing a length of about 10 em. Depth of head at occiput at least equalling length
of cranium. Premaxilla elongate-triangular in shape, bearing a close series of
small conical teeth on its oral border, and two much-enlarged teeth within,
these somewhat laterally-compressed but without sharp edges; maxilla with
gently convex oral border, bearing a regular series of small stout teeth, slightly
largest on the middle of the convexity and decreasing in size backwards ;
mandible rapidly tapering to an almost pointed symphysis, with a series of
laterally-compressed, not sharp-edged teeth, which are longest just m front
of the middle of the ramus, and very small just behind the symphysis. The
teeth generally marked with a few very fine vertical strie.
1 Elopopsis heckeli, A. E. Reuss, Denkschr. k. Akad. Wiss., math.-naturw. Cl., vol. xiii (1857),
p- 39, pl. ui; A. Fritsch, Rept. u. Fische bohm. Kreideform. (1878), p. 41, fig. 61.
2 Elopopsis ziegleri, W. von der Marck, Palxontogr., vol. xv (1868), p. 293, pl. xli, figs. 2—4.
134 FOSSIL FISHES OF THE ENGLISH CHALK.
Description of Specimens.—The type specimen in the Brighton Museum (Willett
Collection, no. 61) comprises the head with the anterior part of the abdominal
region of a large fish, much fractured and crushed, exhibiting part of the
pectoral fin on the left side and part of the dorsal fin behind. The right side
of the head is represented in Pl. XXVIII, fig. 2, an upper view of the ethmoidal
region is given in fig. 2a, and separate drawings of the left premaxilla and
imperfect dentary are given in figs.2) and 2c. There are more fragmentary
specimens in the British Museum, two of these exhibiting a considerable portion
of the trunk. There is also a specimen in the collection of Mr. Henry C. Drake,
¥.G.8., of Hull.
The superficial bones show no ornamentation, merely the lines of growth, and
in places sensory canals. The cranial roof (so far as it can be examined in the
type specimen and in B. M. no. P. 10218) appears to resemble that of Pachyrhizodus
(Text-fig. 39), both in general contour and in the separation of the parietals by a
small supraoccipital bone. The mesethmoid (Pl. XXVIII, fig. 2 a, eth.) is short
and broad, truncated in front. The cheek is completely covered with thin bony
plates, which are for the most part smooth and never tuberculated. There are
three postorbitals (fig. 2, po.), which are marked only by inconspicuous radiating
grooves and by the usual slime-canal, from which a few branches radiate back-
wards (B. M. no. P. 10320). The lowest postorbital, which is the largest, meets a
long and narrow suborbital plate (so.), which rapidly tapers at each end and is
only marked on the middle of its smooth outer face by a few ridges radiating
apparently from the traversing slme-canal. The antorbital must have been small,
but is unknown.
The mandibular suspensorium is nearly vertical, so that the quadrate articula-
tion is beneath the occiput. The premaxilla (fig. 2, pmw.; fig. 26) is relatively
small, elongate-triangular in shape, and does not meet its fellow of the opposite
side in the median line, the wide mesethmoid intervening. On its oral margin the
bone bears a single regular series of very stout, small, conical teeth, which are
sometimes slightly inclined backwards and inwards. Within this outer row the
premaxilla also bears one or two comparatively large, smooth, conical teeth. In
the type specimen (fig. 2) the anterior inner tooth, shown only by the base, is the
smaller of the two; while the well-preserved, posterior inner tooth occurs at about
the middle of the bone. Both are somewhat laterally compressed, but not to sharp
edges. ‘The maxilla (fig. 2, mw.) is very large, extending backwards beyond the
orbit, and overlapped above by a long and narrow supramaxilla (sma.), which
tapers to a point in front. The upper border of the maxilla is notched near its
anterior end just behind the prefrontal facette, and at the extremity of the
suborbital cheek-plate; its oral border is gently convex and curves slightly
inwards. The maxillary teeth resemble the teeth of the premaxilla, but, except
at the anterior end, they are somewhat larger, and they are often distinctly
ELOPOPSIS. 135
marked by vertical striations at the base (fig. 35). Behind the few foremost, the
teeth are remarkably uniform in size, and in the gaps between them may be seen
the points of developing successional teeth (Brit. Mus. no. P. 10337). Their
apices are frequently blunt, as if worn. ‘The dentary bone of the mandible is
imperfect and mot well seen in the type specimen (fig. 2c), but is better shown by
a comparatively small specimen (fig. 3). It tapers in front to an almost pointed
symphysis, where it is thickened at the surface of contact with its fellow of the
opposite side. The oral border of the bone is wavy in front, and the lower part
of its outer face is traversed by a deep longitudinal groove, in which would
probably le the slime-canal. On the edge of the dentary there is a single series
of sharply-pointed conical teeth, which are somewhat laterally compressed (though
not to sharp edges), and marked with vertical striations (fig. 3a). In the anterior
convexity these teeth are quite small, but those of the rest of the series are much
larger than the marginal teeth of the upper jaw. The developing successional
teeth evidently alternate with those in function. The large inner symphysial
tooth (seen in fig. 2c, its base in fig. 3) 1s a little laterally compressed, but nearly
round in section. Many sections of teeth are observable in the fossils and exhibit
no trace of a pulp-cavity.
The bones of the opercular apparatus are remarkably thin, large, and smooth,
showing only a shght waviness parallel with the margins. The preoperculum
(fig. 2. pop.) is much expanded at the angle and in the lower lmb, and bears
marks of slme-canals which radiate backwards from the main slime-canal of its
anterior border. ‘The branchiostegal rays must have been numerous, in probably
not less than 20 pairs, according to the type specimen, but only the hinder 14
pairs are satisfactorily known (B. M. no. P. 10320).
The vertebral centra (fig. 2d) are strengthened by a few longitudinal ridges,
which extend between the stout anterior and posterior rims. They are not much
constricted, and none are longer than deep. The neural and hemal arches in the
caudal region are much flattened from side to side, and sharply inchned backwards.
In the pectoral arch, the clavicle, supraclavicle, and post-temporal are expanded
into large, smooth plates, which are thin and readily flake in the fossils. There
also appear to be enlarged postclavicular scales. The fins are almost unknown,
but the base of the dorsal in B. M. no. P. 10217, shows that it was in the middle
of the back, not remote.
The scales are large, thin, and very deeply overlapping, arranged m regular
series. Their small exposed sector is sometimes quite smooth, sometimes impressed
by very small pittings (fig. 4). The lateral line does not appear to form a ridge,
but the canal traversed by it is conspicuous in flaked specimens.
Affinities—In the characters of its maxillary dentition H. crassus agrees most
closely with H. ztegleri, from the Cenomanian of Westphalia, but these two species
apparently differ in their mandibular dentition.
136 FOSSIL FISHES OF THE ENGLISH CHALK.
Horizon and Localities.—Zone of Rhynchonella cuvieri: Wouldham, Kent
(G. E. Dibley Coll.) ; South Ferriby, Lincolnshire (H. C. Drake Coll.). Probably
zone of Terebratulina gracilis: Malling, near Lewes, Sussex. Probably also zone
of Schloenbachia varians: Barrington, Cambridge (Sedgwick Museum).
Genus THRISSOPATER, Giinther.
Thrissopater, A. Giinther, Figs. and Descript. Brit. Organic Remains, dec. xiii (Mem. Geol. Surv.,
1872), No. 1.
Generic Characters—Trunk somewhat laterally compressed; abdomen com-
pressed to an edge. Skull as in Pachyrhizodus. Teeth conical and enamelled
nearly to the base, where they are fused with the supporting bone; a single series
in the dentary, premaxilla, and maxilla. Premaxilla without inner horizontal
extension; a single supramaxilla. Vertebree about 50 m number, the centra
rarely deeper than long, slightly constricted, smooth or delicately ridged. An
enlarged postclavicular scale above the pectoral fin; pelvic fins opposed to the
short dorsal; anal fin relatively small; caudal fin deeply forked. Scales small or
of moderate size, usually ornamented with delicate radiating ridges; no enlarged
or thickened ridge-scales ; lateral line inconspicuous.
Type Species.—Thrissopater salmoneus (Ginther, loc. cit., 1872, no. 1, pl. 1),
from the Gault of Folkestone, Kent.
Remarks.—This genus appears to differ only very shghtly from Pachyrhizodus.
The dentition is more feeble, without inner teeth on the premaxilla. The trunk
seems to have been less rotund.
A skull showing a gular plate, which I once assigned to T'hrissopater (Catal.
Foss. Fishes B. M., pt. iv, p. 35), now proves to belong to Osmeroides. The gular
plate, therefore, still remains unknown.
1. Thrissopater megalops, A. 8S. Woodward. Plate XXVIII, fig. 5.
1901. Thrissopater (?) megalops, A. 8. Woodward, Catal. Foss. Fishes B. M., pt.iv, p. 35, pl. vii, fig. 4.
Type.—Imperfect head probably from zone of Holaster subglobosus ; British
Museum.
Specific Characters.—Posterior suborbital plates relatively narrow, their extent
not exceeding one quarter the length of the skull; orbit very large, its width con-
siderably greater than one third the length of the skull; teeth of premaxilla
relatively long and slender, larger than those both of the maxilla and dentary.
Opercnlar apparatus relatively narrow, its width not exceeding one third the
length of the skull. Radiating lines on anterior scales few and indistinct.
PROTELOPS. 137
Description of Specimen.—The only satisfactory specimen of this species
hitherto discovered is the type (Pl. XXVIII, fig. 5). It is an imperfect head,
broken in the rostral region, but sufficiently well preserved to exhibit its generic
and specific characters. The typical constitution of the hinder part of the cranial
roof is clearly seen, and there is the usual longitudinally-extended median
depression. ‘The comparatively short and deep postorbital cheek-plates (po.) are
three in number; and above them there appears to have been another plate (w.)
which extended forwards enough to meet the deep and narrow antorbital (ao.)
above the large orbit. There is a single suborbital (so.) below the eye. . i" ri,
‘Va ;
F1a.
eS)
6.
NI
PLATE XXXI.
Protosphyrena ferox, Leidy ; rostrum, left side view, with imverted
symphysial end of dentary beneath, one half nat. size; also (1a, 1)
two transverse sections of rostrum showing extent of internal
cavity, one half nat. size.—Zone of Holaster subglobosus ; Blue Bell
Hill, Burham, Kent. 8. J. Hawkins Collection (B. M. no. P. 6529).
d., dentary inverted ; v., vomer.
Ditto; right premaxilla, incomplete behind, outer and (2a) lower
views, two thirds nat. size—Ibid. Mrs. Smith’s Collection (B. M.
no. 49012).
Ditto ; left premaxilla, incomplete anteriorly, outer view, two thirds
nat. size.—Ibid. Harford Collection (B. M. no. P. 5634).
Ditto; right maxilla, inner view, with (4) lower view of anterior end.
—Ibid. Harford Collection (B. M. no. P. 5651a). y., antero-
internal process.
Ditto; portion of large left maxilla, outer view.—Zone of Holaster
subglolosus ; Halling, Kent. Wetherell Collection (B. M. no. 45092).
Ditto; left mandibular ramus, incomplete behind, outer and (6a) upper
views, one half nat. size.-—Chalk; Kent. Enniskillen Collection
(B. M. no. P. 3955). d., dentary ; spl., splenial.
Ditto; lower front tooth, inner view, showing hollow (s.) for successional
tooth at base.—Zone of Holaster subglobosus; Blue Bell Hill,
Burham. §. J. Hawkins Collection (B. M. no. P. 6550).
Ditto; transverse section of part of tooth, highly magnified, also (8)
outline of transverse section of tooth.
Unless otherwise stated, figures are of the natural size.
PAGE.
148.
148.
148.
149.
149.
149,
150.
150.
PALAZONTOGRAPHICAL SOCIETY,1908.
A.S. Woodward, English Chalk Fishes. PIO
West, Newman imp
A.H.Searle del.et lith.
Protosphyrena.
Eira.
bo
6.
PATH XXOCH.
Protosphyrena ferox, Leidy; anterior end of right mandibular ramus,
outer, (1 a) upper, and (10) end views.—Chalk; Kent. Bowerbank
Collection (B. M. no. 39438). d., dentary ; spl., splenial.
Protosphyrena sp.; hypural bone, showing anterior process (p.) and a
Chalk ; Sussex.
few overlapping fin-rays (7.), two thirds nat. size.
Egerton Collection (B. M. no. P. 1483).
Ditto; hypural bone, showing large anterior process (p.), two thirds
nat. size-—Cambridge Greensand. B. M. no. 35160 a.
Ditto; portion of pectoral fin, two thirds nat. size.—Zone of Holaster
subglobosus ; Merstham, Surrey. B. M. no. 41079.
Ditto; preaxial portion of upper end of left pectoral fin, showing the
rays (7.) clasping the first and second baseosts (1, 11), anterior and
(5a) upper views.—Chalk; Kent. Toulmin Smith Collection
(B. M. no. 41695).
Ditto; portion of left pectoral arch with base of fin, posterior and (6)
English Chalk. 3B. M. no.
P. 7573. cl., clavicle; cor., coracoid; f., vacuity; pc., pre-
inner views, two thirds nat. size.
coracoid; 7., fin-rays; sc., scapula; vill, eighth baseost.
Unless otherwise stated, figures are of the natural size.
PAGE.
150,
LO:
150.
150.
PALZZEONTOGRAPHICAL SOCIETY,!I908.
A.S.Woodward, finglish Chalk Fishes. Pi i
A.H.Searle del.et lith.
West,Newman imp
Protosphyrena.
PALAHONTOGRAPHICAL SOCIETY.
INSTITUTED MDCCCXLVIL.
VOLUME FOR 1908.
LONDON:
MDCCCCVITI.
TYPE SPECIMENS OF INFERIOR OOLITE AMMONITES.
THE type specimens of Ammonites concavus, A. murchisone, A. striatulus, and
A. jugosus, originally described and figured by the Sowerbys in their ‘ Mineral
Conchology,’ have already been re-figured and discussed by Mr. 8. 8. Buckman in
his ‘ Monograph of the Ammonites of the Inferior Oolite Series,’ vol. i, published
by the Paleontographical Society in parts between 1887 and 1907. The type
specimens of the other species in the Sowerby Collection are now illustrated by
new figures in the accompanying seven plates. It has been deemed useful to
reprint the original descriptions for reference.
It has not been possible to trace the type specimens of Ammonites braikenridgi,
A. brongniarti, A. contractus, and A. gervillii.
eS TIO Rabat is.
I.—Ammonites banksii.
II.— as blagdeni.
TL— - a and A. banksi, with text-figures of A. sowerbit.
Ye xa brocchit.
Vi— ¥e brodiwi and A. parkinsoni.
VI.— = leviusculus, A. subradiatus, A. corrugatus, and A. brown.
VII— ,, humphriesianus and A. brodict.
Unless otherwise stated, the figures are of the natural size.
ILnUSTRATIONS
PY ee een CEE BINS
OF
INFERIOR OOLITE AMMONITES
[IN fe SOWERBY- COLLMCTION.
PDE BY SE, Senn TAN:
HON DON:
PRINTED FOR THE PALAONTOGRAPHICAL SOCIETY.
1908.
The Palzontographical Society is indebted to Mr. 8. 38.
Buckman, F.G.S., for assistance kindly rendered in_ the
preparation of several of these Plates.
PLATE I.
Ammonites banksii, J. Sowerby, Min. Conch., vol. 11, p. 229, 1818, pl. ce.
[ Brit. Mus. no. 43910. |
© Snecific Characters.—Discoid, very thick; inner turns exposed; sides concave,
largely tuberculated ; front fluted, shghtly convex; aperture transverse, almost
three times as long as wide.
“A very bold formed shell; the narrow sides of the whorls are much relieved
from each other, they are convex, and occupied by about 10 large obtuse tubercles:
the great width of the convex margin, which is obtusely fluted, gives the whole a
very massive appearance. There are about five turns, the last but one is in
diameter equal to the thickness of the whole.
“In a valuable packet of fossils belonging to the Inferior Oolite, sent by some
disinterested friend at present unknown to me, from the west of England, was the
ponderous mass represented in this plate; it contains the ferruginous grains
peculiar to that rock, with Belemnites, fragments of other shells, and also a piece
of wood, changed almost into charcoal. I hope my friend will make himself
known, and communicate the locality.
“JT have indulged my feelings of esteem and friendship, by giving this
magnificent Ammonite the name of that staunch supporter of science in general,
and of natural history in particular, who has presided so long and so ably over
the Royal Society.”
[See also Pl. ITI, fig. 2.]
PALZ ONTOGRAPHICAL SOCIETY, !908.
Types, Interior Oohte Ammonites -
A Dat. size
.H. Michael del. et hth
? ih 4 na
. ~
PAB le
Anmonites blagdeni, J. Sowerby, Min. Conch., vol. 1, p. 231, 1818, pl. eci.
[Brit. Mus. no. 43908. |
* Specific Characters.—Subcylindrical, obtusely fluted, umbilicate; umbilicus
reaching to the margin, conical, with large radi terminating upon the edge in a
tubercle ; aperture transverse, quadrangular, three times as wide as long.
“The umbilicus is deep; 1t occupies the whole side; the tubercles round its
edges, about 22 in each turn, are obtuse in the cast of the inside, but where there
are some remains of the outer surface they appear ‘to be spiniform, there are four
or five furrows on the front to each; the front is very shehtly convex.
“A massive specimen from the lower Oolite, containing Belemnites, other
Ammonites, etc.: it was given to me by my lamented friend, Dr. J. C. Lettsom.
I have named it after the Imghly discerning, meritorious, yet most unassuming
Sir Charles Blagden. The analogy between this and the preceding may remind
conchologists of the long cordial friendship subsisting between Sir Charles and Sir
Joseph Banks.”
[See also Pl. ITI, fig. 1.]
PALA.ONTOGRAPHICAL SOCIETY, 1908.
Oolte Ammonites. PL. IL.
Bale & Danielsson, 14 imp
Ammonites blagdem.
PLATE III.
F ta.
1. Ammonites blagdeni, J. Sowerby ; front view of specimen, Brit. Mus. no. 43908.
2. Ammonites banksii, J. Sowerby; front view of specimen, Brit. Mus. no. 49910.
Side view, nat. size. Inner whorls, enlarged. Portion of outer whorl, enlarged.
Ammonites sowerbui, J. Sowerby, Min. Conch., vol. ui, p. 285, 1818, pl. cexiii.
[ Bristol Museum. |
** Specific Characters.—Discoid, carmated, with about eight spiniform tubercles
upon each whorl; keel defined, entire; aperture elliptical. Var. 8 aperture
circular, keel sometimes impressed.
** Volutions about four, the inner ones concealed to the bases of the tubercles ;
the outer part of the volutions has many gentle undulations; the imner part is
even, except that the base of each tubercle is extended towards the centre in an
obtuse ridge. The keel nearly separated from the body of the shell; it is round
and entire.
“In var. B the ridges from the bases of the tubercles are more prominent, and
the keel sometimes so far sunk as to have a furrow on each side of it. The inner
whorls of var. a appear to be more gibbose than the outer ones.
“Mr. Miller considers the shell figured as one of his rarest specimens ; his
collection has also to boast of several smaller specimens, belonging to var. 8, which
vary in the gibbosity of the whorls; they were all found at Dundry, in the Inferior
Oolite.”’ .
PALAZONTOGRAPHICAL SOCIETY, I908.
lypes, Inferior Oohte Ammomites Pl.
i,
oe
perter on
ete
Bale & Damelsson, ita amp
F.H Michael del. et bth
PASE | Vs,
Ammonites brocchii, J. Sowerby, Min. Conch., vol. 1, p. 233, 1818, pl. ecii.
[Brit. Mus. no. 43906. ]
“ Specific Characters.—Compressed ; sides hollow, radiated ; inner whorls half
concealed ; front circular, with many obtuse ridges; aperture lunate.
“ Volutions three or four, very round ; twenty radii extending nearly half over
them; the rest of their surface is covered by nearly six times as many obtuse,
arched, not very prominent ridges. Were the hollow sides considered as
umbilicate, the umbilicus would be conical but would have no defined edge; the
aperture is lunate, inclining to transversely elliptical. Thickness half the diameter.
The septa are remarkably numerous, and finely sinuated.
“From the same friend, and probably from the same place, although of a greyer
colour, as A. banksw, 1 received the large specimen; it seems to have been exposed
to the weather.
“The small specimen is from Dundry, by favour G. W. Braikenridge, Esq.
“The name is to commemorate the author of a recent valuable work upon the
fossil shells of his own country.”
1908.
PALZ.ONTOGRAPHICAL SOCIETY,
ieee
Types, Inferior Oohte Ammonites.
Bale & Danielsson, Lt¢ imp .
F.H. Michael del et hth.
jaunt
=
Ammonites broce
ite te
ee a
‘
h gtr
-T , aa
PLATE “Y;
ia,
1. Ammonites brodicei, J. Sowerby, Min. Conch., vol. iv, p. 71, 1822, pl. eccli. [ Brit. Mus. no. 43905. ]
“ Specific Characters. —Largely umbilicate, gibbose, costated ; coste radiating, large and numerous,
terminated upon the sides of the whorls by obtuse tubercles, front rounded, plicated; aperture
transversely oblong, curved.
“Somewhat resembling Ammonites broechii, tab. 202, but less gibbose and more strongly marked.
The radiating ribs are shehtly curved: from each of the tubercles that terminates them proceed about
four plaits or lesser ribs, that pass around the front, and meet the tubercles upon the opposite side:
this part of the inner volutions is concealed.
“This shell was given me a long while ago, as found on Portland Island, but with some doubt, by
my kind and worthy friend, Jas. Brodie, Esq., whose name I wish to perpetuate: from the appearance
of the stone I should rather suspect it to have come from the under or Ironshot Oolite.”
[See also Pl. VII, fig. 3. ]
Fie.
2. Ammonites parkinsoni, J. Sowerby, Min. Conch., vol. iv, p. 1, 1821, pl. ccevii. [| Brit. Mus. no. 43925. |
“ Specific Characters.—Discoid, with numerous highly elevated radii; whorls numerous, the imner
ones exposed ; radii slightly arched, bifid near the front which is very narrow and plain.
“ Volutions numerous, with slightly convex sides and narrow edges: the arched radii are bent
forward at their outer ends, and nearly meet at an acute angle upon the front, but do not pass over
it: the edge of the shell is nearly flat, in the cast it is hollow in consequence of the removal of the
siphuncle ; the aperture is oblong, narrowest towards the front.
“This is the Ammonite so frequently split, polished, and sold at Bath: its outer surface is also
often ground and polished, showing ramifying, sinuated, or simply undulated edges to the septa,
according to the depth to which it has been worked. Misled by worked specimens that had lost the
flat space in the middle of the edge, I have erroneously referred this species to the Am. giganteus,
at page 55 of vol. i while speaking of such as are found near Keynsham, and those fine specimens
given me by Dr. Lettsom, all of which are flatter than even the variety a of the giganteus, and have
more whorls. The species before us occurs chiefly in Lyas, a stratum not known to contain any
silicious deposit; it is consequently never imbedded in Chert or Flint, like the A. giganteus B. I
suspect it also may be found in the lower beds of the Ironshot Oolite, as the specimen now figured is
from near Yeovil, and contains vestiges of ferruginous grains. Iam indebted to the kind attention
of Dr. W. E. Leach for preserving it from the gothic hands of the mason, who is often as destructive
of the essential characters of fossils, as some dealers still continue to be of the natural forms of recent
shells, and who rob them without mercy of venerable coats that had resisted with various success the
combined efforts of numerous sea-born enemies, whose ravages even leave marks more worthy of
contemplation than the formal beauty betrayed by the file or polishing brush. -
“A section, showing the chambers filled partially with crystallised Carbonate of Lyme, is given at
tab. 12 of British Mineralogy. It often extends to 18 inches or more in diameter, and when cut thin
and viewed by transmitted light, offers a specious excuse for the unscientific mason.”
1908.
PALAZONTOGRAPHICAL SOCIETY,
AWA
Ee
Tmonites
3 abervor wo olate sAten
Bale & Damielsson, Lt amp
del. et lath
el
ne
c.Ammonites parlanson
rodicei.
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SC
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1. Ammonit
PLATE VI.
Fras.
1,2. Ammonites leviusculus, J. de C. Sowerby, Min. Conch., vol. v, p. 73, 1824, pl. eceeli, figs. 1, 2.
[| Brit. Mus. no. 43950 a, b.]
“ Specific Characters.—Discoid, carinated, umbilicated, obscurely radiated; carina distinct; radii
waved, alternately long and short, slightly elevated ; umbilicus. small, exposing parts of the inner
whorls ; aperture sagittate.
“ One half of the diameter of the shell is occupied by the aperture, a third of the other half by the
umbilicus, in full grown individuals; in young ones the umbilicus is larger. The front is obtuse with
a large prominent keel in the middle of it; the sides are rather convex marked with waved, elevated
radii, that are broader and less conspicuous on the outer whorls of the full grown shells. In young
shells the aperture is oblong, rather square; as the shell grows older, the aperture becomes longer,
more deeply notched by the preceding whorl, and narrower towards the front.
“Found in the inferior or Ironshot Oolite, at Dundry by G. W. Braikenridge, Esq., to whose
liberality we are indebted for a series of specimens.”
Fie.
3. Ammonites subradiatus, J. de C. Sowerby, Min. Conch., vol. v, p. 23, 1823, pl. cecexxi, fig. 2.
[ Brit. Mus. no. 43943. |
“ Specific Characters.—Lenticular, umbilicated, carinated, and radiated; radii twice curved,
ob[s jcure excepting near the margin, where they are bifid; umbilicus small; keel entire; aperture
sagittate.
“The edge of this lenticular Ammonite is rather obtuse, and the carina not much relieved ; the
sides are nearly smooth, for the curved radii are very obscure excepting near the edge after they have
become forked or divided, as some of them are, into three or even four short ribs; the thickness is
about one fifth of the diameter.
“ Found several years ago on the road from Bath to Bristol; it has been broken out of a mass of
the Ironshot Oolite; no other specimen has reached our Cabinet.”
Fie.
4. Ammonites corrugatus, J. de C. Sowerby, Min. Conch., vol. v, p. 74, 1824, pl. ccccli, fig. 3.
[| Brit. Mus. no. 43951 a. |
“ Snecific Characters.—Discoid, carimated and umbilicated, strongly radiated; carina distinct ;
radii waved, sometimes furcated, elevated; umbilicus broad, exposing parts of the inner whorls ;
aperture obovate ; front obtuse.
““Resembling the last {Ammonites leviusculus|, but thicker, with more prominent radi, and a
broader front.
“ From Dundry, with the A. leviusculus.”
Fie.
5. Ammonites browni, J. Sowerby, Min. Conch., vol. i, p. 114, 1820, pl. cclxiu, figs. 4, 5.
[ Brit. Mus. no. 43966. |
“ Specific Characters.—Discoid, with radiating undulations ; inner whorls half exposed, with large
tubercles upon each side; marginal undulations many, central ones few, rising into tubercles ; front
rounded with a distinct keel; aperture cordate.
“Tn general appearance very much like the last [Ammonites koenigi|, but rather thicker and
sufficiently distinguished by the keel and knobs upon the inner volutions.
“From Dundry, by favour of my good friend G. W. Braikenridge, Esq. I wish by the name of
this Ammonite to commemorate R. Brown, Esq., a gentleman of general knowledge and an excellent
botanist.”
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PALA ONTOGRAPHICAL SOCIETY. 1908.
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PE Aa VA:
Fras.
1,2. Ammonites humphriesianus, J. de C. Sowerby, Min. Conch., vol. v, p. 161,
£329; PL DS fie: a. [ Brit. Mus. nos. 43908 a, b. |
“ Specific Characters.—Discoid, thick, radiated, inner whorls exposed; front
rounded, radii large, numerous, rising into a tubercle on each side of the whorl,
where they branch into three ; aperture arched, oblong.
“Composed of about four or five whorls, which are almost wholly exposed,
more especially the outer ones; the radii are straight, gradually rising towards a
conical tubercle, which in the outer whorls occupies about the middle of each side,
and is distant from the suture, but in the inner ones is placed close to the suture
that separates the turns; the inner whorls have a much flatter front than the
outer, whence their sections are quadrangular, whilst the aperture of a large shell
is almost lunate.
“The two specimens figured of this Ammonite are from the stock of
Mr. George Humphries. They were marked Sherborne, and appear to come from
the Ironshot or Inferior Oolite: the larger one is only a polished half.
The same
species occurs abundantly at Bayeux in Normandy of a brighter colour.”
Fie.
3. Ammonites brodiwi, J. Sowerby; front view of specimen. Brit. Mus.
no.
43905.
PALZONTOGRAPHICAL SOCIETY, 1908.
Types, Inferior Oohkte Ammonites Pl Wie
FH. Michael del. et bth Bale & Damelsson,! td mp
>
LC 7 fs ) \ \ £ = Fs 2
1.2. Ammonites humphresianus. 5. Ammonites brodicet.
ae
he
ox
Ks
Ve ny
Palxontographical Society, 1908.
A MONOGRAPH
OF THE
CRETACKOUS LAMELLIBRANCHTA
ENGLAND.
HENRY WOODS, M.A.
UNIVERSITY LECTURER IN PALHZOZOOLOGY, CAMBRIDGE,
VOL. Ik PARTY.
VENERIDA, CARDIIDH, DICERATIDH, MONOPLEURIDA, AND
CORBULIDA.
Paces 181—216; Puares XXVITI—XXXIV.
HONDON:
PRINTED FOR THE PALMONTOGRAPHICAL SOCIETY.
1908.
‘=
PRINTED BY ADLARD AND SON, LONDON AND DORKING.
DOSINIOPSIS. 181
Genus—Dosiniopsis, 7’. A. Conrad, 1864.
(‘ Proc. Acad. Nat. Sci. Philadelphia,’ p. 213.)
Dosiniopsis susroruNDA (Sowerby), 1836. Plate XXVIII, figs. 1—6.
1836. Cyrueraa suprotunDA, J. de C. Sowerby. ‘Trans. Geol. Soc., ser. 2, vol. iv,
pp. 240, 341, pl. xvii, fig. 2.
1850. VeENus = A. @Orbigny. Prodr. de Pal., vol. ii, p. 159.
1854. CyrHEerea — J. Morris. Cat. Brit. Boss.; ed. 2; p. 201.
1870. Venus FI’. Stoliczku. Paleeont. Indica, Cret. Fauna S.
India, vol. in, p. 161 (Caryatis).
Description—Shell rather thick, rounded, oval or somewhat orbicular, of small
or moderate convexity ; length rather greater than height; moderately, sometimes
considerably, inequilateral. Antero-dorsal margin long, concave. Anterior
margin rounded, passing gradually into the considerably curved ventral margin.
Postero-dorsal margin very long, convex, with a considerable ventral slope.
Posterior margin rounded. Umbones small, pointed, close together, shghtly
curved anteriorly. Lunule elongate, depressed, distinctly limited. Escutcheon
narrow, depressed, with a sharp border. Pallial sinus rather large, sub-angular.
Ornamentation consists of fine concentric striz, and growth-lines.
Hinge: In the right valve three strong, nearly straight, diverging cardinal
teeth, of which the anterior and median are closer together and diverge at a
smaller angle than the median and posterior, the last being divided by a shallow
longitudinal groove; there is a small posterior lateral tooth and an elongate
anterior pit. In the left valve the anterior of the three diverging cardinal teeth is
nearly vertical, the median is the stoutest, and the posterior is oblique and slender ;
the anterior lateral tooth is elongate and parallel to the lunular margin; the
posterior lateral is very small.
Measurements :
(1) (2) (3) (4) (5)
Length . 34 31 29 28 5 26 mm.
Height . 32 : 28 ; PAGS I 26 : 23D, Ss
(1—5) Blackdown.
From Blackdown; in the Bristol Museum.
Type.
Distribution.—Upper Greensand (zone of Schlanbachia rostrata) of Blackdown.
24,
182 CRETACHOUS LAMELLIBRANCHIA.
Dosinropsis CAPERATA (Sowerby), 1826. Plate XXVIII, figs. 7—10.
1826. Venus caperata, J. de C. Sowerby. Main. Conch., vol. vi, p. 31, pl. dxvin,
fies. 1-3.
1850. — — A. dOrbigny. Prodr. de Pal, vol. ii, p. 159.
1854. CyruEerEa — J. Morris. Cat. Brit. Foss., ed. 2, p. 200.
1865. Venus caperara, I’. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste.
Croix (Matér. Pal. Suisse, ser. 4),
pe 189:
1868. -- A. Briart and F. L. Cornet. Meule de Bracquegnies
(Mém. cour. et Mém. des Sav.
étrangers, vol. xxxiv), p. 74, pl.
vu, figs. 6—8.
1870. — == I’. Stoliczha. Paleeont. Indica, Cret. Fauna S. India,
vol. 11, p. 160 (Caryatis).
? Non 1845. = — A. @Orbiqny. Pal. Frane Terr. Crét., vol. ii, p. 445,
gny ‘ \y
pl. ccelxxxv, figs. 9, 10 (V. wniformis,
Prodr. de Pal., vol. 1, p. 236).
Description.—Shell oval, convex, moderately or considerably inequilateral ;
length rather greater than height. Antero-dorsal margin concave. Anterior
margin rounded, passing gradually into the convex ventral margin. Posterior less
convex than the anterior margin, sometimes subtruncate. | Postero-dorsal margin
long, shghtly convex. Umbones prominent, curved anteriorly. Lunule ovate.
Palhal sinus rather large, sub-angular. Ornamentation consists of strong, regular,
concentric ribs.
Hinge: In the right valve three stout cardinals separated dorsally, the anterior
and median being close together and nearly vertical, the posterior oblique and
divided by a longitudinal groove ; there is an anterior elongate pit and a strong
posterior lateral tooth. In the left valve the median is the stoutest of the three
vardinals and is sometimes joined dorsally to the nearly vertical anterior cardinal ;
the posterior cardinal is slender and very oblique; the anterior lateral is strong,
elongate and parallel to the lunular margin.
Measurements :
(1) (2) (3) (4) (5) (6) (7) (8)
engihye ote a ob. 80. 28 2926 6 25.5 21 .- elo mm.
Heigtitpeer o0so) 20 0. oO MP e2aro sy 22, 28 .. | NBO V4,
(1—8) Blackdown.
Remarks.—Internal casts from the Folkestone Beds of Pulborough were
referred to this species by Forbes. I have not seen any specimens which would
enable me to record the occurrence of J). caperata in the Lower Greensand.
CYPRIMERIA. 183
Lype-—From Blackdown; in the British Museum.
Distribution.—Upper Greensand (zone of Schlaubachia rostrata) of Blackdown
and Haldon. Recorded by Barrois from the Upper Greensand of Lulworth, and
by Jukes-Browne from the Upper Greensand of the Isle of Wight.
Genus—Cyprimeria, 7’. A. Conrad, 1864.
(‘ Proc. Acad. Nat. Sci. Philad.,’ 1864, p. 212, and ‘Amer. Journ. Conch.,’ vol. ii, 1866, p. 102.
Stoliczka, ‘ Palaont. Indica, Cret. Fauna 8. India,’ 1870, p. 157.)!
Subh-genus—Cycrorisma, W. H. Dall, 1903.
(‘ Proc. U.S. Nat. Mus.,’ vol. xxvi, 1903, p. 357. Syn. Cyclothyris, T. A. Conrad in W. C. Kerr’s
‘Geol. Rep. N. Carolina,’ vol. i, Appendix 1 (1875), p. 8. Non Cyclothyris, M’Coy, 1844.)
Cyprimerta (Cycnorisma) vectensis (Morbes), 1845. Plate XXVIII, figs. 11—18.
1845. Venus vecrensis, H. Forbes. Quart. Journ. Geol. Soc., vol. i, p. 240, pl. 11,
fio. 4.
1850. — — A. d Orbigny. Prodr. de Pal., vol. ii, p. 118.
1854. — — J. Morris. Cat. Brit. Foss., ed. 2, p. 231.
1865. — — FJ. Pictet and G. Campiche. Foss. Terr. Crét. Ste.
Croix (Matér. Pal. Suisse, ser. 4),
p- 188.
1870. - — F. Stoliczka. Paleont. Indica, Cret. Fauna 8S. India,
vol. i, p. 160.
? 1883. — — W. Keeping. Foss., ete. Neoc. Upware and Brickhill,
p. 125.
Description.—Shell oval, or nearly orbicular, a little longer than high, regularly
convex, slightly or moderately mequilateral. Margin rounded. Umbones small,
pointed, somewhat curved forwards. Lunule indistinct, not impressed, limited by a
faint line. Palhal sinus angular, directed upwards. Margins of valves smooth.
Surface of shell smooth except for small, mconspicuous, concentric ridges, and
occasional growth-rings.
Hinge: In the right valve an anterior and a median cardinal and two posterior
laminar teeth (which together represent the posterior cardinal) diverge from
under the umbo; the anterior is directed forwards, the median is nearly vertical,
1 The following European species are referred by Conrad and by Stoliezka to the genus
Cyprimeria: Cyclina primeva, Zitt., Dosinia eretacea, Zitt., Circe discus (Math.), Circe concentrica,
Zitt., and Arcopagia rotundata, @Orb. Holzapfel figures Cyprimeria Geinitzi (Mill.) and C. moneta,
Holz., from the Aachen Greensand.
184. CRETACKOUS LAMELLIBRANCHIA.
and the two posterior slope obliquely backwards. In the left valve a long, oblique
laminar, posterior cardinal; a median cardinal (which is divided); and an
anterior cardinal, diverge under the umbo, from which they are separated by a
narrow space or channel. In front of the anterior cardinal the anterior part of
the hinge-plate is concave.
Measurements :
(1) (2) (3) (4) (5)
Length . 38 32 : 31 28 24 mm.
Height . 34. ; 29D 29 26 ZrO! a5
(1—5) Crackers, Atherfield.
Affinities —This species shows some resemblance to Venus vendoperana
(Leymerie), especially to the example figured by Pictet and Renevier,! but the
umbones are less prominent and the lunule is less distinct.
Type.—The type came from the Crackers of Atherfield, but cannot now be
found.
Distribution.—Lower Greensand (Crackers) of Atherfield. Recorded from
the Atherfield Clay and Bed vi of Atherfield by Fitton. Recorded by Topley
from the Atherfield Beds of Peasmarsh and Shalford.?
Cyprimeria (Cycnortsma) parva (Sowerby), 1826. Plate XXVIII, figs. 19—23 ;
Plate XXIX, figs. 1—3.
1826. Venus parva, J. de C. Sowerby. Min. Conch., vol. vi, p. 32, pl. dxvin,
figs, 4—6.
1845. Lucrna ¥ sonrpuLA, FE. Forbes. Quart. Journ. Geol. Soc., vol. i, }». 239, pl. ii,
ioe lg
1850. Venus parva, A.d’Orbigny. Prodr. de Pal., vol. ii, p. 159 (not Blackdown).
== Luctna soniputa, @Orbigny. Ibid., vol. ii, p. 118.
1854. Cyrnerea PARVA, J. Morris. Cat. Brit. Foss., e!. 2, p. 201 (partim).
Luctna sonipuLa, Morris Ibid., ed. 2, p. 208.
1865. Venus parva, F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. Croix
(Matér. Pal. Suisse, ser. 4), p. 188.
1870. — — F. Stoliczka. Paleont. Indica, Cret. Fauna 8. India, vol. 1,
p. 160 (Caryatis).
— Lucina ? soripuna (? Mysta), Stoliczka. Ibid., vol. iii, pp. 252, 262.
? 1895. Venus ef. parva, H. Tiessen. Zeitschr. d. deutsch. geol. Gesellsch., vol. xlvii,
p. 484.
1 Pictet and Renevier, ‘Foss. Terr. Aptien’ (‘ Matér. Pal. Suisse,’ ser. 1, 1855-56), p. 71, pl. vii,
fig 9. Pictet and Campiche, ‘Terr. Crét. Ste. Croix’ (‘Matér. Pal. Suisse,’ ser. 4, 1865), p. 181, pl. exi,
12:
x
=h
9
I have not seen the specimen recorded by Keeping from Upware.
CYPRIMERIA. 185
Non 1840. Venus parva, A. Goldfuss. Petref. Germ., vol. ii, p. 246, pl. cli, fig. 4
(V. Goldfussi, Geinitz, 1850; V. subparva,
VOrbigny, 1850).
— 1841. — — F. A. Romer. Die Verstein. d. nord-deutsch. Kreidegeb.,
p. 72 (Venus subinflexa, Romer, 1836).
— 1846. = — A. FE. Reuss. Die Verstein. der bohm. Kreideformat., pt. 2,
320; pl. xiy tess Vos 7.
== 1 fexa33. — — A. v. Strombeck. Zeitschr. der deutsch. geol. Gesellsch.,
vol. xv, p. 146.
—- 1868. — — A. Briart and F. L. Cornet. Meule de Bracquegnies (Mém.
cour. et Mém. des Sav. ¢trangers,
vol. xxxiv), p. 75, pl. viii, figs. 1, 2.
— 1877. CyrHerea parva, G. Bohm. Zeitschr. der deutsch. geol. Gesellsch., vol. xxix,
p. 241.
— 1883. Venus cf. parva, A. Fritsch. Stud.im Gebiete der bohm. Kreideformat., iii,
Iserschicht., p. 109, fig. 77.
— 1885. Venus parva, F. Notling. Die Fauna d. baltisch. Cenoman. (Paleont.
Abhandl., vol. 11), p. 32, pl. v, fig. 11.
—= lees}. = — Fritsch. Op. cit., v, Priesen. Schicht., p. 98, fig. 118.
Description—Shell small, oval, convex, moderately imequilateral. | Antero-
dorsal margin slightly concave, or nearly straight, formmg a rounded angle with
the anterior margin which curves rapidly to join the convex ventral margin.
Posterior margin rounded or subtruncate. Postero-dorsal margin slightly convex.
Umbones rather prominent, curved inwards and forwards. Lunule broad, ovate,
more or less projecting, limited by a groove. Palhal simus large, angular.
Ornamentation consists of small, somewhat irregular, concentric ribs, and occasional
erowth-rings.
Hinge: In the right valve the anterior and median cardinals are stout and
nearly parallel, and the two posterior teeth (which represent the posterior cardinal)
are oblique and diverging; in front of the anterior cardinal is a groove, bounded
by a ridge above and below, parallel to the inner margin of the hinge-plate. In
the left valve the anterior and median cardinal teeth diverge widely under the
umbo and the posterior cardinal is oblique; the anterior cardinal 1s continued
forward into a ridge along the inner margin of the hinge-plate.
Measurements :
(1) (2) (3) (4) (5) (6) (7) (8)
engi. 2075 21). 205 20" 19, 6s | 4S 0" mm!
Bleraite ea NAP oa, Hedy. sie Ole lege aallOmem, mAs See Dinos,
(1) Perne-bed, East Shalford.
(2—8) Crackers, Atherfield.
The differences between this species and C. (Cyclorisma) rotomagensis
Affinities.
are given below.
The form from Bracqueentes, which was referred to Venus parva by Briart and
Cornet, is less elongate.
186 CRETACEOUS LAMELLIBRANCHIA.
The hinge differs from that of other species of Cyclorisma in that the anterior
tooth in the left valve is continued forwards into a ridge at the inner margin of
the hinge-plate.
Lucina ? solidula, Forbes, appears to be identical with Venus parva, Sowerby ;
the type is missing, but other specimens which are in the Museum of the Geological
Society and were probably identified by Forbes, are undoubtedly examples of
V. parva. The type of Lucina ? solidula, so far as one can judge from the figure,
seems to have been rather shorter than most examples of Venus parva.
Venus Orbignyana, Forbes! from the Crackers of Atherfield, is stated to be
allied to V. parva. The type is missing, but a specimen named J’. Orbignyana in
the Museum of the Geological Society appears to be a small example of Cyprina
Saussurt (p. 181).
Remarks.—Examples of this species vary somewhat in convexity, in relative
height and length, in the prominence and position of the umbones, and in the
projection of the lunule at the margin where the valves meet. The types are
internal casts from Parham, and they agree, except in being shghtly more convex,
with casts from Hast Shalford, where specimens with the shell preserved are also
found. The latter do not differ from the perfectly preserved specimens found in
the Crackers of Atherfield.
T'ype.—From the Sandgate Beds of Parham Park, in the British Museum.
Distribution.—Lower Greensand: Perna-bed, Crackers, and Bed 45 of Ather-
field. Perna-bed of Sandown. Atherfield Beds of Peasmarsh and Shalford.
Sandgate Beds of Parham Park.
Cyprimmria (Cyctortsma) roromacEnsts (d’Orbigny), 1845. Plate XXIX, figs. 4—6.
1845. Venus rHotomacensis, A. d’Orbigny. Pal. Frang. Terr. Crét., vol. iii, p.
443, pl. ecelxxxv, figs. 1—5.
1850. — porHomacensts, d’Orbigny. Prodr. de Pal., vol. 1, p. 194.
1865. - rotomaAceEnsis, I’. J. Pictet and G. Compiche. Foss. Terr. Crét.
Ste. Croix (Matér. Pal. Suisse,
ser. 4), p. 190.
1870. = F.. Stolickza. Paleeont. Indica, Cret. Fauna S.
India, vol. iii, p. 161 (? Caryatis).
Remarks.—The English examples of this species are internal casts occasionally
with small portions of the shell preserved. D’Orbigny’s specimens were obtained
1 «Quart. Journ. Geol. Soc.,’ vol. i (1845), p. 240, pl. ii, fig. 5; d’Orbigny, ‘ Prodr. de ales
vol. ii (1850), p. 118; Morris, ‘Cat. Brit. Foss.,’ ed. 2 (1854), p. 231; Pictet and Campiche, “ Foss.
Terr. Crét. Ste. Croix’ (‘Matér. Pal. Suisse,’ ser. 4, 1865). pp. 184, 188; Stoliczka, ‘Paleont. Indica,
Cret. Fauna 8. India,’ vol. 11 (1870), p. 160.
CY PRIMERIA. 187
from the Cenomamian of Rouen. Hnelish specimens agree with those found at
Rouen, except that in many cases the shell is somewhat shorter relatively. The
surface is ornamented with concentric ribs. In C. (Cyclorisma) rotomagensis the
shell is more convex, more inequilateral, and the postero-dorsal margin has a
greater slope than in C. (Cyclorisma) parva. The hinge appears to be unknown.
Distribution.—Base of the Chalk Marl of Maiden Newton and Chard. Chloritic
Marl of Melbury, Woolcombe, Maiden Bradley and the Isle of Wight.’
Cyprimerta (CychorismMa) FaBpa (Sowerby), 1827. Plate XXIX, figs. 7—13.
1827. Venus rasa, J. de C. Sowerby. Min. Conch., vol. vi, p. 129, pl. dlxvii, fig. 3.
1850. — — A.d@Orbigny. Prodr. de Pal., vol. u, p. 159 (partim).
1854. = — J. Morris. Cat. Brit. Foss., ed. 2, p. 230 (partim).
1868. — — A. Briart and F. L. Cornet. Meule de Bracquegnies (Mémn.
cour. et Mém. des Sav. ctrangers,
vol. xxxiv), p. 73, pl. vii, figs.
9 10:
1870. = — F. Stoliczka. Palewont. Indica, Cret. Fauna S. India, vol. iii,
p. 160.
1873. — — H. B. Geinitz. Das Elbthalgeb. in Sachsen (Paleonto-
graphica, vol. xx, pt. 2), p. 65, pl. xvin,
fies. 9, 10.
J. Kiesow. Schrift. d. nat. Gesellsch. in Danzig, N.F., vol. v,
p. 239.
? 1885. — — F. Notling. Die Fauna d. baltisch. Cenoman. (Paleont.
Abhandl., vol. 11), p. 32, pl. vi, fig. 1.
xv
—
GO
CO
is)
|
|
Non 1840. — — A. Goldfuss. Petref. Germ., vol. ii, p. 247, pl. cli, fig. 6 (V.
subfaba, d’Orbigny).
— 1848. = — H. B. Geinitz. Die Verstein. von Kieslingswalda, p. 13, pl. ii,
figs. 7—9.
== JE. — — A.dOrbigny. Pal. Franc. Terr. Crét., vol. in, p. 444, pl.
ecelxxxv, figs. 6—8.
— 1846. _- — A. E. Reuss. Die Verstein. der béhm. Kreideformat., pt. 2,
p. 21, plexi, ney:
— 1847. — — J. Miiller. Petref. der Aachen. Kreidef., pt. 1, p. 24.
— 1859. — uimmeERsA, Miller. Ibid., Supplement, p. 13.
-— 1863. — FaBa, A. v. Strombeck. Zeitschr. d. deutsch. geol. Gesellsch., vol.
xv, p. 147.
1 An imperfect left valve from the Cenomanian (Bed 12) of Whitecliff, South Devon, was
identified by C. J. A. Meyer with Venus Goldfussi, Geinitz, ‘Das Quadersandst. oder Kreidegeb. in
Deutschland’ (1850), p. 154, pl. x, figs. 7, 8; ‘Das Elbthalgeb. in Sachsen’ (‘ Palzeontographica,’ vol.
xx, pt. 2, 1873), p. 67, pl. xviii, figs. 16, 17. There is not sufficient evidence to confirm this identifica-
tion ; the anterior part of the specimen is more produced than in the case of the examples figured by
Geinitz.
188 CRETACEOUS LAMELLIBRANCHIA.
Non 1863. Venus rasa, ht. Drescher. Ibid., vol. xv, p. 348.
— 1884. Cyprimerta FraBA, HL. Holzapfel. Ibid., vol. xxxvi, p. 467, pl. vu, fig. 1.
— 1889. Tapers rasa, H. Holzapfel. Die Mollusk. Aachen. Kreide (Palonto-
graphica, vol. xxxv), p. 165, pl. xiii, figs. 7-10.
— 1897. Venus (Tapes) rasa, A. Fritsch. Stud. im Gebiete der bohm. Kreide-
format., vi, Chlomek. Schicht , p. 63,
fig, 80.
— 1901. F. Sturm. Jahrb, d. k. preussisch. geol. Landesanst.
fiir 1900, vol. xxi, p. 82.
Description.—Shell oval, of moderate convexity, with flattened sides, con-
siderably inequilateral. Antero-dorsal margin short, shehtly concave. Anterior
margin rounded, passing gradually imto the slightly convex ventral margin.
Postero-dorsal margin long, slightly convex, with a moderate or considerable
ventral slope. Porterior margin short, rounded or subtruncate. Umbones small.
Lunule elongate, not impressed, faintly limited. Ornamentation consists of small,
regular, concentric ribs.
Hinge: In the right valve the anterior and median cardinals are stout, diverge
shghtly, and are directed forwards, and reach the lower margin of the hinge-
plate; the two posterior teeth (which represent the posterior cardinal) are
laminar, oblique and diverging. In the left valve the anterior and median
cardinals are rather stout and diverge; the posterior cardinal is slender and
oblique. In front of the anterior cardinal there is a concave space on the hinge-
plate in both valves.
Measurements :
(1) (2) (3) (4) (5)
Length . 30 ; 29 : 29 . 28 ; 27 mm.
Height. 25 24. 22 : 21 22a.
(1—5) Blackdown.
Affinities —Venus Archiaciana, dOrbigny,' from the Senonian of Charente-
Inférieure, is somewhat similar in form to CU. (Cyclorisma) fuba, but the surface
of the shell is smooth.
A species found in the Aachen Greensand has been identified by Goldfuss,
Holzapfel, and others with Sowerby’s Vewus faba, but was regarded as distinct by
VOrbigny and G. Miller. It differs from Sowerby’s species in the greater
curvature of the ventral margin and the more pointed posterior extremity ; also the
posterior teeth in the right valve are less widely separated and are more oblique.
In d’Orbigny’s figure of Venus faba the ornamentation is coarser than in English
examples, but a specimen from the Cenomanian of Rouen (one of the localities
cited by d’Orbigny) differs but little in this respect from Blackdown specimens.
Remarks.—Vhe principal variation consists in the amount of the ventral slope
1 «Pal. Frang. Terr. Crét.,’ vol. iii (1845), p. 449, pl. ceclxxxvi, figs. 6, 7.
CLEMENTIA. 189
of the postero-dorsal margin. In the type specimen that slope is small, so that
the outline of the shell-is distinctly oval. The position of the umbones also varies,
so that some specimens are more inequilateral than others.
Specimens found in the Gault of Black Ven are usually somewhat crushed and
often larger than Blackdown examples ; some are more elongate and agree closely
with Venus sublevis, Sowerby (see below).
Type.—¥rom Blackdown; in the British Museum.
Distribution.—Upper Greensand (zone of Schlenbuchia rostrata) of Blackdown
and (?) Devizes. Gault of Black Ven.
CYPrRIMERIA (CYCLORISMA) SUBLEVIS (Sowerby), 1836. Plate X XIX, fig. 14.
Y)s » Wg
1836. Venus? sustavis, J. de C. Sowerby. Trans. Geol. Soc., ser. 2, vol. iv, pp.
242, 342, pl. xvu, fig. 5.
1850. Venus susitmvis, A. d’Orbigny. Prodr. de Pal., vol. ii, p. 159.
1854. — = J. Morris. Cat. Brit. Foss., ed. 2, p. 231.
1870. — = F. Stoliczka. Paleont. Indica, Cret. Fauna S. India,
vol. ii, p. 161.
Remarks.—The only specimen which I have seen is the type. It differs from
QO. (Cyclorisma) faba only in being more elongate, and seems to be merely an
individual variation. Venus immersa, Sowerby,! also known by the type only
(Plate XXIX, fig. 15), does not appear to differ from V. sublevis. The types of
both are in the Bristol Museum and come from the Upper Greensand of Blackdown.
Genus—CLuEMENTIA, J. H. Gray, 1840.
(‘Synopsis Brit. Mus.,’ p. 149.)
Sub-genus—Fiavenvia, A. J. Jukes-Browne, 1908.
(‘ Proc. Malacol. Soc.,’ vol. vii, p. 167.)
CiementTIA (FLaventiA) Ricorpeana (d’Orbigny), 1845. Plate XXIX, figs. 16—18.
1845. Venus Ricorpeana, A. d’Orbigny. Pal. Franc. Terr. Crét., vol. ii, p. 431,
pl. ceclxxxu, figs. 1, 2.
1 Sowerby, ‘Trans. Geol. Soc.,’ ser. 2, vol. iv (1886), pp. 242, 342, pl. xvu, fig. 6; d’Orbigny,
‘Prodr. de Pal.,’ vol. ii (1850), p. 159; Morris, ‘Cat. Brit. Foss.,’ ed. 2 (1854), p. 231; Stoliczka,
‘Paleont. Indica, Cret. Fauna S. India,’ vol. 1ii (1870), p. 161. Non Venus immersa, Miller, ‘ Petref.
der Aachen. Kreidef.,’ Supplement (1859), p. 13; Reuss, ‘ Die Verstein. der bohm. Kreideformat.,’
pt. 2 (1846), p. 20, pl. xli, fig. 11; Kner, ‘ Denkschr. d. k. Akad. Wissensch. Wien, Math.-Nat. Cl.,’
vol. ii (1852), p. 311, pl. xvi, fig. 20.
25
190 CRETACHKOUS LAMELLIBRANCHIA.
1850. Venus RrcorpEana, A. d’Orbigny. Prodr. de Pal., vol. 11, p. 76.
1855. — = G. Cotteau. Moll. Foss. de ’Yonne, p. 64.
1865. — — F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste.
Croix (Matér. Pal. Suisse, ser. 4),
p. 169.
1870. — = F’. Stolicaka. Paleout. Indica, Cret. Fauna S. India,
vol. ii, p. 159.
Description.—Shell oval, convex with flattened sides, considerably inequilateral,
anterior part higher than the posterior part. Anterior margin regularly rounded,
passing gradually into the slightly curved ventral margin. Postero-dorsal margin
long, convex, with a considerable ventral slope. Posterior margin short, oblique,
forming a rounded angle with the ventral margin. Umbones broad, curved
forwards. The part of the shell behind a line between the umbones and the
postero-ventral angle slopes rapidly from the flattened sides. Lunule elongate,
limited by a groove. Escutcheon elongate, deep, limited by a sharp edge.
Ornamentation consists of sharp concentric ridges. Pallial sinus angular,
somewhat ascending.
Measurements :
(1) (2) (3) (4) (5)
Length 56 52 ; 52 : 50 ; 43 mm.
Height ; AZ 40) 39 35 34 a,
(1) Atherfield Beds, Peasmarsh.
(2, 5) Perna-bed, Atherfield.
(3) Hythe Beds, Lympne.
(4) Hythe Beds, Pulborough.
Affinities. —English specimens differ from d’Orbigny’s figure in the more rapid
ventral slope of the postero-dorsal margin. Jam indebted to Professor Boule for
comparing photographs of specimens trom the Lower Greensand with the examples
in the d’Orbigny collection which appear to be the types, and he states that in
the latter the shell is less elongate and the postero-dorsal border has a greater
slope than in d’Orbigny’s figure, consequently the photographs agree much more
closely with the types than with the figure. M. A. de Grossouvre has been good
enough to lend me a specimen of CU. (laventia) Ricordeana from the Lower Aptian
of Seignelay, Yonne, one of the localities mentioned by dOrbigny, and a
comparison of that with English examples leaves no doubt as to their specific
identity.
The generic position of Clementia (Flaventia) Ricordeana is at present some-
what uncertain since none of the specimens shows the hinge; but on account of
the resemblance in the form of the shell to that of C. (Flaventia) ovalis it is
probable that this species belongs to the sub-genus Flaventia. C. (laventia)
CLEMENTITA. Om
Ricordeana is less elongate and its postero-dorsal margin is more convex and slopes
more rapidly than in Venus sub-Brongniartiana VOrbigny.!
Remarks.—This is probably the species which has been recorded by some
authors from the Lower Greensand as Venus ovalis and Astarte substriata, Leymerie.
The proportions of length and height vary considerably in different specimens.
Distribution.—Lower Greensand (Perna-bed) of Atherfield. Atherfield Beds
of Hast Shalford, Redhill, and Peasmarsh. Hythe Beds of Hythe, Lympne, and
Pulborough. ®
CLEMENTIA (FLAVENTIA) OvALIS (Sowerby), 1827. Plate X XIX, figs. 19—26.
] g
1827. Venus ovauis, J. de C. Sowerby. Min. Conch., vol. vi. p. 129, pl. dlxvu,
fig. 1 (not fig. 2).
1850. _: — A.dOrbigny. Prodr. de Pal., vol. ii, p. 159.
1854. _ — J. Morris. Cat. Brit. Foss., ed. 2, p. 231 (mot from the
localities given).
1870. — — F. Stoliczka. Paleont. Indica, Cret. Fauna S. India, vol.
ili, p. 160.
Non 1840. —- —_ A. Goldfuss. Petref. Germ., vol. ii, p. 247, pl. cli, fig. 5
(Venus subovalis, VOrbigny, 1850).
— 1846. ~- — A. H. Reuss. Die Verstein. der béhm. Kreideformat., pt. 2,
p. 21, pl. xxxiv, fig. 22.
— 1847. — — J. Miiller. Petref. der Aachen. Kreidef., pt. 1, p. 24.
== Meio) = — H.Credner. GZeitschr. d. deutsch. geol. Gesellsch., vol. xx,
joy UATE
— 1884. Cyrnerra ovatts, HE. Holzapfel. Ibid., vol. xxxvi, p. 464, pl. vii, figs. 2—4.
— 1888. -— — G. Miller. Jahrb. d. k. preussisch. geol. Landesanst. fiir
1887, p. 427.
— 1889. a — Fi. Holzapfel. Die Mollusk. Aachen. Kreide (Paleon-
tographica, vol. xxxv), p. 169, pl. xiii,
figs. 11—15.
— — VENUS — A. Fritsch. Stud. im Gebiete der bohm. Kreideformat.,
iv, Teplitz. Schicht., p. 80, fig. 69.
— 1898. CyrnerrA — _ G. Miiller. Mollusk. d. Untersen. v. Braunschweig u.
Ilsede, p. 66. pl. ix, fig. 15.
— 1901. — — F. Sturm. Jahrb. d. k. preussisch. geo]. Landesanst. fiir
1900, vol. xxi, p. 88.
Description.— Shell clongate-oval, of moderate convexity, considerably nequi-
lateral. Antero-dorsal margin rather long, concave. Anterior margin rounded,
1 Leymerie, ‘Mém. Soe. géol. de France,’ ser. 2, vol. v (1842), pp. 5, 25, pl. v, fig. 7; d’Orbigny,
‘Pal. Franc. Terr. Crét.,’ vol. iii (1845), p. 482, pl. ecelxxxii, figs. 3—6; Pictet and Campiche, ‘Terr.
Crét. Ste. Croix’ (1865), p. 168, pl. exi, fig. 1.
192 CRETACEOUS LAMELLIBRANCHIA.
passing gradually into the considerably curved ventral margin. Postero-dorsal
margin long, convex. Posterior margin short, rounded. Umbones prominent,
pointed, with a considerable anterior curvature. Lunule ovate, faintly limited.
Ornamentation consists of growth-rings and (in well-preserved specimens) of
numerous small, regular, concentric ribs. Pallial sinus deep, ascending, with
rounded end.
Hinge: In the right valve the anterior and median cardinals are strong, and
diverge below the umbo ; the posterior cardinal is long, oblique, curved, and
divided into two parts of which the anterior is shorter than the posterior. In
the left valve the anterior and median cardinals are strong and diverge below
the umbo; the posterior cardinal is laminar and very oblique.
Measurements :
(1) (2) (3) (4) (5) (6)
Iheneth 7 44° AO. 37 ---34 =; 32°. 380 mm,
Meret =. oo, . Bl e.o6d2 2 920 <4 27. . 923 4,
(1—6) Blackdown.
Affinities. —The form from the Aachen Greensand which was referred to this
species by Goldfuss and others possesses an anterior lateral tooth.
Remarks.—In Sowerby’s figure the lunule projects more than in any specimen
which I have seen, but in other respects the examples from Blackdown agree with
that figure.
Type.—The type came from Blackdown, but cannot now be found.
Distribution.—Upper Greensand (zone of Schlanbachia rostrata) of Blackdown. !
Recorded by Jukes-Browne from the Upper Greensand of Devizes.
Genus—Catusta, O. A. Ll. Moreh, 1853.
(‘ Catalog. Conchyl. de Yoldi,’ ii, p. 27.)
Canlisra PLANA (Sowerby), 1813. Plate XXX, figs. 1—6.
1813. Venus puanus, J. Sowerby. Min. Conch., vol. i, p. 58, pl. xx, lower figures.
1854. CyrHErEA puaAna, J. Morris. Cat. Brit. Foss., ed. 2, p. 201.
21845. Venus pruana, A. d’Orbigny. Pal. Frang. Terr. Crét., vol. iii, p. 447, pl.
ecelxxxvi, figs. 1—3 (? partim).
! The type of Venus submersa, Sowerby, from the Upper Greensand of Pinhay, cannot be found.
I have seen no specimen which could be referred to that species. Barrois, however, records it from
the Upper Greensand of Lulworth. J. de C. Sowerby, ‘Trans. Geol. Soc.,’ ser. 2, vol. iv (1836), pp. 242,
342, pl. xvii, fig. 4; d’Orbigny, ‘ Prodr. de Pal.,’ vol. ii (1850), p. 159; Morris, ‘Cat. Brit. Foss.,’ ed. 2
(1854), p. 231; Stoliczka, ‘ Palwont. Indica, Cret. Fauna S. India,’ vol. iii (1870), p. 161 (Caryatis)
Barrois, ‘ Terr. Crét. Supér, de l’Anglet. et de l’Trelande ’ (1876), p. 90.
CALLISTA. 193
1850. Venus piana, A. d’Orbigny. Prodr. de Pal., vol. 1, p. 159.
1865. a — EF. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. Croix
(Matér. Pal. Suisse, ser.
4), p. 190.
1867. — — HE. Guéranger. Album Paléont. de la Sarthe, p. 13, pl. xvii,
fig. 11.
1868. — — A. Briart and F. L. Cornet. Meule de Bracquegnies (Mém.
cour. et Mém. des Say.
étrangers, vol. xxxiv), p. 72,
pl. vil, figs. 3—5.
? Non 1846. Venus puana, A. H. Reuss. Die Verstein. der bohm. Kreideformat., pt. 2,
p. 21, pl. xli, fig. 14.
? — 1879. CyruErREa (Caryatis) pLANA, J. F. Whiteaves. Mesoz. Foss., vol. i (Geol.
Surv. Canada), p. 149,
pl. xvii, fig. 14.
Description.—Shell oval, sometimes more or less triangular, rounded, moderately
convex, considerably inequilateral; length greater than height. Antero-dorsal
margin long, concave. Anterior part of valve more or less produced, with
rounded margin. Ventral margin forming a considerable curve. Posterior margin
short, rounded or slightly truncate. Postero-dorsal margin convex, much longer
than the antero-dorsal margin. Umbones rather prominent, pointed, close
together, curved anteriorly. Lunule long, cordiform, distinctly limited.
Escutcheon not defined. Ornamentation consists of small concentric ridges, with
stronger growth-ridges at intervals. [Fine radial ribbing is occasionally seen in
the posterior part of well-preserved specimens. Pallial sinus fairly large, angular
or sub-angular, shghtly ascending.
Hinge: In the right valve the anterior and median cardinals are nearly
vertical, slightly diverging, and separated dorsally, the posterior cardinal is
oblique, long and divided, its posterior part is much longer than the anterior part,
and the latter nearly meets the anterior cardinal under the umbo; in front of the
cardinal teeth there is a shallow, elongate pit with shghtly raised upper and lower
margins. In the left valve the stout anterior and median cardinals diverge from
under the umbo, the anterior tooth being nearly vertical; there is a long slender,
oblique posterior cardinal, and an elongate, ridge-like anterior lateral tooth, which
is grooved or corrugated.
Measurements :
( (2) (3) (4) (5) (6) (7) (8) (9)
Length . 72 69 638 62 54 652 48 44 35
Height . 63 5/7 0653 51 46 48 41 37 29
(1—9) Blackdown.
mm.
bb)
Affinities. —Specimens from Senonian deposits of Kurope have been referred to
194, CRETACEOUS LAMELLIBRANCHIA.
Venus planus, Sowerby, by several authors;' and so far as I can judge from the
few figures which have been published, they seem to differ but little from
Sowerby’s species. ‘The example from Aachen figured by Goldfuss agrees closely
with specimens from Blackdown except that the lIunule projects more at the
margin. Holzapfel has compared Aachen with Blackdown specimens, and
confirms Goldfuss’s identification. The example figured by d’Orbigny® differs
in having a large and deep escutcheon.
Specimens from the Trichinopol Group (near the base of the Ariyaliir Group)
were identified by Stohezka*® with Venus planus.
~The absence of a channel under the anterior right cardinal, and the occurrence
of fine radial ornameritation connect this species with Callista. The palhal sinus,
however, resembles that of Pitavia. The anterior lateral tooth in the left valve is
much less prominent, and the corresponding pit in the right valve much smaller
and shallower than in either Callista or Pitarvia. This species is the type of the
section or sub-genus Callistina, Jukes-Browne.*
This is a common fossil at Blackdown. The variations seen
Remarks.
consist in the proportion of height to length, the more or less triangular or oval
outline, and the more or less produced anterior part of the shell.
Type.—From Blackdown; in the British Museum.
Distribution.—Upper Greensand (zone of Schlaenbachia rostrata) of Blackdown
and Haldon. Recorded by Jukes-Browne from the Upper Greensand of Devizes,
the Isle of Wight, ete.
Family—CARDIID AL, Lamarck.
Genus—Prorocarnia, H. Beyrich, 1845.
(‘ Menke’s Zeitschr. f. Malakozool.,’ p. 17.)
PROTOCARDIA ANGLICA, sp. nov. Plate XXX, figs. 7 a,b; Plate XXXI, fig. 1.
Description.—Shell large, convex, with flattened sides, subquadrate, moderately
1 Goldfuss, ‘ Petref. Germ.,’ vol. ii (1840), p. 238, pl. exlvii, fig. 4; Miller, ‘ Petref. der Aachen.
Kreidef.,’ (1847), pt. 1, p. 25; Drescher, ‘ Zeitschr. d. deutsch. geol. Gesellsch.,’ vol. xv (1863), p.
344; Brauns, ‘ Zeitschr. f. d. gesammt. Naturwiss.,’ vol. xlvi (1876), p. 868; H. Schroder, ‘ Zeitschr.
d. deutsch. geol. Gesellsch.,’ vol. xxiv (1882), p. 275; Holzapfel, ‘Die Mollusk. Aachen. Kreide’
(‘ Paleontographica,’ vol. xxxv, 1889), p. 171, pl. xiii, figs. 16—18; Vogel, ‘Hollindisch. Kreide’
(1895), p. 42.
2 D’Orbigny subsequently separated the Senonian form under the name Venus subplana, ‘ Prodr.
de Pal.,’ vol. ii (1850), p. 237. See also V. Renauwxiana, dOrbigny, ibid., p. 194.
3 Stoliezka, ‘ Paleeont. Indica, Cret. Fauna 8. India,’ vol. 11 (1870), pp. 151, 160, 169, pl. vii, figs.
1—4.
* Proce. Malacol. Soc., vol. viii (1908), p. 156.
PROTOCARDIA. 195
inequilateral, length and height nearly equal. Antero-dorsal margin nearly
straight. Anterior margin convex, curving rapidly to join the ventral margin,
which is moderately or slightly convex. Posterior margin truncated, forming
angles with the ventral and postero-dorsal margins. Umbones large, curved
forwards, with a sharp carina extending in a curve to the postero-ventral angle
and limiting the flattened, steeply-sloping posterior area, the dorsal portion of
which is concave. Shell depressed in front of the umbones.
Ornamentation: Sides of shell nearly smooth except for numerous, very small,
concentric ribs which are separated by flat interspaces. ‘The posterior area 1s
covered, except near the postero-dorsal margin, by 12 strong radial ribs.
Measurements :
(1) (2) (3)
Length ‘ 80 ; 76 : 46 mm.
Height . 78 Waa 46s
(1—-3) Crackers, Atherfield.
Affinities—This species resembles P. Forbesi (Pictet and Renevier),' from the
Lower Aptian of Ste. Croix, but the umbones are less prominent, and the ribs on
the posterior area are less numerous.
It is also similar to P. dimpressa (Deshayes),” but is distinguished by the
smaller curvature of the ventral margin, the greater flattening of the sides of the
shell, and the more considerable curvature of the umbones.
Distribution.—Lower Greensand (Crackers) of Atherfield.*
PROTOCARDIA SPHHROIDEA (Forbes), 1845. Plate XXXI, figs. 2, 3.
1845. Carpium spHmRoipium, H. Forbes. Quart. Journ. Geol. Soe., vol. i
p. 243. pl. ii, fig. 8.
1850. — == A. @Orbigny. Prodr. de Pal., vol. ii, p. 79.
1852. = NECKERIANUM, I’. J. Pictet and W. Roux. Moll. Foss. Grés
verts de Genéve, pp. 424,
425, pl. xxx, fig. 3.
= — SPHHROIDEUM, Pictet and Roux. Ihbid., p. 546.
1854. — — J. Morris. Cat. Brit. Foss., ed. 2, p. 193.
?
1 «Foss. Terr. Aptien’ (‘Matér. Pal. Suisse, ser 1, 1856), p. 79, pl. viii, fig. 4; Pictet and
Campiche, ‘Terr. Crét. Ste. Croix (Matér. Pal. Suisse, ser. 4, 1866), p. 261.
2 D’Orbigny, ‘Pal. Frang. Terr. Crét.,’ vol. iii (1844), p, 20, pl. ccxl; Pictet and Campiche,
op. cit., p. 249.
3 Some specimens of Protocardia from the Lower Greensand of Atherfield were referred by Forbes
to Curdium peregrinorsum, VOrbigny, but that identification was doubted by Pictet and Campiche.
The specimens at present available are insufficient for exact determination. See Forbes, ‘ Quart.
Journ. Geol. Soc.,’ vol. 1 (1845), p. 243.
196 CRETACKOUS LAMELLIBRANCHIA.
1856. Carprum spHmroipreum, I’. J. Pictet and FE. Renevier. Foss. Terr. Aptien
(Matér. Pal. Suisse, ser. 1),
Dada ple ix, lige 3.
1866. _ —- FE. J. Pictet and G. Campiche. Foss. Terr. Crét.
Ste. Croix (Matér. Pal. Suisse,
ser. 4), p. 260.
1871. = = (¢ Lavicarpium), EF’. Stoliczka. Paleont. Indica,
Cret. Fauna 8. India,
vol. ii, p. 213.
Description.—Shell stout, large, much inflated, Ingher than long, slightly
inequilateral. Anterior and ventral margins rounded. Posterior margins trun-
cated, forming angles with the postero-dorsal and ventral margins. Umbones
prominent, with a small forward curvature, and an inconspicuous carina extending
to the postero-ventral angle and lhmiting the flattened postero-dorsal area.
Ornamentation consists of regular, broad, flat, concentric ribs separated by
narrow grooves. On the posterior area strong growth-ridges are present.
Measurements :
(1) (2) (3) (4) (5)
Length . 79 76 : es ‘ 69 : 47 mm.
Height . 84. ‘ 91 ‘ 87 87 ’ 48,
(1—5) Perna-bed, Isle of Wight.
Affinities —Pictet and Campiche state that this species is very near to
C. imbricatavium (Deshayes),! but that the posterior area is more flattened and
forms an angle with the sides of the shell; also the truncated posterior margin is
relatively longer.
Remarks.—In this species the radial ornamentation of the posterior area is
either very indistinct or quite obsolete. There is considerable variation im relative
height and length of the shell.
T'ype.—From the Lower Greensand (Perna-bed) of Sandown; in the Museum
of the Geological Society.
Distribution.—Lower Greensand (Perna-bed) of Atherfield and Sandown.
Recorded by Topley from the Hythe Beds of Hythe.
ProrocarpiA, sp. Plate XX XI, fig. 4.
The collection of Upper Greensand fossils made by the late W. Vicary, which
is now in the British Museum, contains two imperfect right valves (No. L 17041)
1 D’Orbigny, ‘ Pal. Frang. Terr. Crét.’ (1844), vol. iii, p. 18, pl. ccxxxix, figs. 4—6; Leymerie,
‘Mém. Soc. géol. de France,’ ser. 2, vol. v (1842), p. 4, pl. v, fig. 2; Pictet and Campiche, ‘Terr.
Crét. Ste. Croix’ (‘ Mater. Pal. Suisse,’ ser. 4, 1866), p. 258, pl. cxxi, figs. 6,7. The specimens referred
to C. imbricatarium by Forbes are examples of Unicardium vectense (p. 163) ; see Forbes, ‘ Quart.
Journ. Geol. Soc.,’ vol. 1 (1845), p. 243.
PROTOCARDIA. no7
from Haldon, which resemble in shape the higher forms of P. spheroidea, but the
umbones are narrower and more curved, and the carina is more distinct.
Better specimens are needed before a satisfactory comparison can be made. The
occurrence of P. sphxroidea in the Upper Greensand (zone of Pecten asper) of
Wiltshire has been recorded by Mr. Jukes-Browne.
ProrocarDIA, sp. Plate XXXI, fig. 5a, b.
(S
Description.—Shell globose, with rounded outline, shehtly mequilateral, height
and length nearly equal. Umbones low, curved anteriorly. The posterior
part of the shell (except near the postero-dorsal margin) is ornamented with from
ten to twelve strong radial ribs; the remainder of the shell bears numerous, small
concentric ribs.
Affinities. —This species resembles P. peregrinorsa (@’Orbigny),' but the area
with radial ribs is relatively larger, and the concentric ribs are finer.
Remarks.—The only specimens seen are two in the Museum of Practical
Geology and two in Mr. Lamplugh’s collection.
Distribution.—Speeton Clay (zone of Belemmnites lateralis, D, 4) of Speeton.*
Prorocarpia Hinnana (Sowerby), 1813. Plate XXXI, figs. 6 a—c; Plate XXXII,
fio. 1—6.
1813. Carprum Hituanum, J. Sowerby. Min. Conch., vol.i, p. 41, pl. xiv
(upper figure).
1819. — — Lamarck. Hist. nat. Anim, sans Vert., vol. vi, p. 20.
1837. —- — A. Goldfuss. Petref. Germ., vol. ii, p. 220, pl. cxliv,
fig. 4.
— — _- FP. Dujardin. Mém. Soe. géol. de France, vol ii
p. 224.
184.0. — — H. B. Geinitz. Char. d. Schicht. u. Petref. des
sachs. Kreidegeb., pt. 2, p. 53.
1841. — = F. A. Romer. Die Verstein. d. nord-deutsch.
Kreidegeb., p. 71.
1842. — ReQquenianum, P. Matheron. Catal. Foss. du Départ. des
Bouches-du-Rhone, p. 157,
pl. xvui, fig. 6.
1 «Pal. Frang. Terr. Cret.,’ vol. iii (1844), p. 16, pl. ccxxxix, figs. 1—3,; Pictet and Campiche,
‘Terr. Crét. Ste. Croix’ (‘ Matér. Pal. Suisse,’ ser. 4, 1866), p. 254, pl. exxi, figs. 1, 2.
2 Internal casts of a globose and nearly equilateral “ Cardiuwm” (perhaps Protocardia), from the
Spilsby Sandstone of Donnington, are in the Sedgwick Museum.
26
198
CRETACEKOUS LAMELLIBRANCHIA.
Carpium Hinuanum, H. B. Geinitz. Die Verstein. von Kieslingswalda,
p13) pleat, tgs. LO salals
= _ A. @Orbigny. Pal. Frang. Terr. Crét , vol. iii, p.
27, pl. ccxliil.
Prorocarpia Hinuana, HL. Beyrich. Menke’s Zeitschr. f. Malakozool., p. 18.
_— -— A. H. Reuss. Die Verstein. der bohm. Kreide-
format., pt. 2, p. 22, pl. xlv,
gear
a — H. B. Geinitz. Grundr. d. Verstein., p. 421,
pl. xix, fig. 4.
Carpium Hiiianum, H. Forbes. Trans. Geol. Soc., ser. 2, vol. vii, p. 146.
~— — A. dOrbigny. Prodr. de Pal., vol. ii, p. 162.
Prorocarpia Hinuana, H. B. Geinitz. Das Quadersandst. oder Kreidegeb.
in Deutschland, p. 154.
Carpium Hitianum, F. Rimer. Kreidebild. v. Texas, p. 49, pl. vi, fig. 12.
Prorocarpia Hitiana, H. G. Bronn. Lethea Geogn., vol. ii, p. 302,
pl. xxx, fig. 12.
Carpium Birrons, A. HE. Reuss. Kreideschicht. i. d. Ostalpen, p. 145,
pl. xxvii, fig. 19.
— Hitianvum, J. Morris. Cat. Brit. Foss., ed. 2, p. 192.
Prorocarpia Hiniana, BR. Drescher. Zeitschr. d. deutsch. geol. Gesellsch.,
vol. xv, p. 346,
Carpium (ProrocarpiaA) Hitiana, K. A. Zittel. Die Bivalv. d. Gosaugeb.,
I, p. 42 [146], pl. vii, figs. 1, 2.
-— Hitxianum, F. J. Pictet and G. Campiche. Terr. Crét. Ste. Croix
(Matér. Pal. Suisse, ser. 4),
pp. 268, 273.
-- — QO. Fraas. Aus dem Orient, I, p. 91.
—- - HB. Guéranger. Album Paléont. de la Sarthe, p. 15,
pl. xx, figs. 3, 11.
— — A. Briart and F. L. Cornet. Meule de Bracquegnies
(Mém. cour. et Mém. des Sav. ctrangers,
vol. xxxiv), p. 66, pl. vii, figs. 4, 5.
Prorocarpia Hiuuana, Ff. Romer. Geol. v. Oberschles., p. 334, pl. xxvi,
fig. 2.
Prorocarpium Hituanum, I’. Stoliczka. Paleont. Indica, Cret. Fauna S.
India, vol. i111, pp. 209, 219, pl. Xi,
figs. 8—10, pl. xii, figs. 1—3.
— _ H. B. Geinitz. Das Elbthalgeb. in Sachsen
(Palzontographica, vol. xx,
pt. 1), p. 230, pl. 1, figs. 11, 12.
CaRrDIUM — var. MoaBITIcUM, L. Lartet. Ann. Sci. géol.,
vol. 111, p. 53, pl. xu, fig. 9.
ProrocarpiA Hiunana, D. Brauns., GZeitschr. f. d. gesammt. Naturwiss.,
vol. xlvi, p. 266.
Prorocarpium HiuiAnum, A. Fritsch. Stud.im Gebiete der bohm. Kreide-
format., il, Weissenberg. u. Malnitz.
Schicht., p. 112, fig. 64.
PROTOCARDIA. 199
? 1878. Prorocarptum Hinianum, O. Fraas. Aus dem Orient. IL Geol. Beobacht.
am Libanon, p. 70.
1882. Carpium (Prorocarpium) Hinianum, P. de Loriol. Gault de Cosne, p.
69, pl. viii, fig. 17.
1884. Protrocarprum Hitnanum, J. F. Whiteaves. Mesoz. Foss. (Geol. Surv.
Canada), vol. i, p. 228,
pl. xxx, fig. 5.
Carpium (Prorocarpta) Hirtanum, C. FE. Hamlin. Mem. Mus. Comp.
Zool., vol. x, No. 3, p. 50.
1895. Protrocarpium Hin.anum, R. Michael. Zeitschr. d.deutsch. geol. Gesellsch.,
wo
|
|
vol. xlv, p. 282.
1897. — — A. Fritsch. Stud. im Gebiete der bohm. Kreide-
format., vi, Chlomek. Schicht.,
p. 52.
— — Rh. Leonhard. Kreidef. in Oberschles. (Pal-
eontographica, vol. xliv), p. 28.
1898. —_ _ A. Fritsch. Stud. im Gebiete der bohm. Kreide-
format., 11, Iserschicht., p. 98.
1901. Prorocarpta Hinnana, F. Sturm. Jahrb. d. k. preussisch. geol. Landes-
anst. fiir 1900, vol. xxi, p. 79.
1902. — -— A. Quaas. Kreidebild. in der libysch. Wiiste
(Paleontographica, vol. xxx, 2),
p. 218, pl. xxiv, fig. 18.
1904. == = R. Fortau. Bull. Instit. Egyptien, ser. 4, no. 4,
p. 331.
— = var. UMKWELANENSIS, Rt. Etheridge, jun. Second
Rep. Geol. Surv. Natal and
Zululand, p. 79, pl. 1, fig. 16.
1906. = — var., H. Woods. Cret. Fauna of Pondoland (Ann.
8. African Mus., vol. iv), p. 307,
pl. xxxvii, fig. 6.
Description.—Shell convex, with flattened posterior slope, nearly equilateral ;
outline more or less sub-quadrate, rounded, sometimes nearly oval; usually a
little higher than long, but rarely with the height and length equal. Anterior
margin either fairly convex and forming a rounded angle with the antero-dorsal
margin, or very convex and passing almost gradually imto the antero-dorsal
margin. Anterior margin passes gradually into the ventral margin, which may be
considerably convex, but is usually only shghtly convex, with its posterior part
nearly straight and forming a more or less well-marked angle with the posterior
margin. The latter is truncated, slightly convex, and forms an obtuse angle with
the postero-dorsal margin. Umbones of moderate size.
Ornamentation consists (except on the posterior part of the shell) of numerous,
very regular, rounded, concentric ribs separated by narrow furrows; these ribs
become smaller or nearly obsolete near the antero-dorsal margin. On the posterior
200 CRETACEOUS LAMELLIBRANCHIA.
slope of the shell, and sometimes for a short distance in front of it, are from 10 to 15
(usually 12 or 13) strong, more or less angular ribs, separated by broad furrows,
both being crossed by well-marked growth-ridges. Sometimes some of these ribs
are divided at their summits by a narrow, longitudinal groove. he ribs become
rather smaller dorsally and are absent near the postero-dorsal margin. Internal
margins of valves smooth, except the posterior part with radial ribs, which is
serrate.
Measurements :
CS) 8) GE) GS) Gai) (= (2) (0) (11) (12)
Length 51 48 44 44 438 41 38 36 36 32 2¢ 19 mm.
Height 47 47 44 42 41 39 36 386 34 295 26 18 ,,
(1—12) Blackdown.
Affinities —Although this species has a very wide geographical distribution
and a long range in time, yet the principal variations seen in specimens found
at different horizons and in different kinds of sediment consist in the number and
coarseness of the concentric ribs. The modifications do not appear to be more
than varietal, and such as would be found at the present day in examples of a widely
distributed species.
In the example from the Cenomanian figured by d’Orbigny the shell is rather
higher and the ornamentation coarser than in specimens from Blackdown, but in
the latter respect it agrees with examples found by the late C. J. A. Meyer in the
Cenomanian of South Devon. One specimen from the Cenomanian of Sarthe,
shown in Guéranger’s photographic illustrations, agrees in its ornamentation with
Blackdown examples.
The Cenomanian form figured by Rémer (1870), and the examples from
higher horizons figured by Geinitz (1843) and by Goldfuss agree closely with Black-
down specimens. Coarser ribbing is found in specimens from the Gault of Cosne,
showing that that character is not limited to examples from horizons above the
Blackdown Greensand.
Protocardia bifrons (Reuss) is more rounded than P. Hillana, but does not seem
to be specifically distinct.
Cardium marticense, Matheron, and C. Requienianum, Matheron, were regarded
by d’Orbigny and by Zittel as synonyms of P. Hillana.
Specimens from the Trichinopoli Group of Southern India were identified with
P. Hillana by Forbes and by Stoliczka, who stated that they were unable to draw
any line of separation between the Indian and Kuropean examples. The concen-
tric ribbing is coarser in most of the Indian forms, and in some the smooth inner
portion of the posterior area is relatively larger than in specimens from Blackdown. !
! See Stoliczka’s fig. 10a.
CARDIUM. 201
P. delicatula, Stoliezka,' and P. pondicheriense (d’Orbigny),’ are allied to
P. Hillana.
P. biseriata (Conrad),? from Syria, possesses coarse concentric ribs, and is
regarded by Blanckenhorn as a variety of P. Hillana.
Remarks.—Hxamples of this species are common at Blackdown, but probably on
account of the uniformity of the conditions under which they lived, do not show
any very striking variations.
There are some differences in the proportion of length and height ; usually the
former exceeds the latter shghtly, but occasionally the two are equal. The outline
of the shell is sometimes oval, but more usually subquadrate. The radial ribs vary
in number from 10 to 15, and sometimes the area with these ribs is continued for a
short distance in front of the posterior slope.
The number of concentric ribs in 10mm. (measured between 34mm. and
44mm. from the umbo) varies from 15 to 19.
T'ype.—From Blackdown, in the British Museum.
Distribution.—Upper Greensand (zone of Schlenbachia rostrata) of Blackdown,
Haldon, Whitecliff (South Devon), Peak Hill near Sidmouth, Devizes, and
Ventnor. Cenomanian of Dunscombe. Recorded by Jukes-Browne from the
Chloritic Marl of the Isle of Wight.
Genus—Carpium, Linneus.
(‘Syst. Nat.,’ ed. 10, 1758, p. 678; ed. 12, 1766, p. 1121.)
Carpium Ispersoni, Forbes, 1845. Plate XXXII, figs. 7—10.
1845. Carprum Issertsont, FH. Forbes. Quart. Journ. Geol. Soc., vol. i, p. 248,
pole wie tikes, BP
1854. = = J. Morris. Cat. Brit. Foss., ed. 2, p. 192.
1856. a — F. J. Pictet and E. Renevier. Foss. Terr. Aptien
(Matér. Pal. Suisse, ser. 1), p. 78,
Plax tes: lh 2:
1866. — — F. J. Pictet and G. Campiche. Terr. Crét. Ste. Croix
(Matér. Pal. Suisse, ser. 4),
p. 262.
1871. — = (Lavicarpium), F. Stoliczka. Paleont. Indica, Cret.
Fauna S. India, vol. iu, p. 213.
1 «Palwont. Indica, Cret. Fauna 8. India,’ vol. iii (1871), p. 220, pl. xiii, fig. 8.
Stoliczka, ibid., p. 220, pl. xii, figs. 4—7.
3 « Official Report U.S. Exped. Dead Sea, etc.,’ by W. F. Lynch (1852), p. 216, pl. vi, figs. 38, 39
(non 40); R, B. Newton, ‘Geol. Mag.,’ (1898), p. 400, pl. xv, fig. 11. P. Hillana var. typica,
M. Blanckenhorn, ‘ Beitr. zur Geol. Syriens: Kreidesyst. in Mittel u. Nord-Syriens’ (1890), p. 89.
202 CRETACEOUS LAMELLIBRANCHIA.
Description.—Shell small, inflated, oval, a little higher than long, shghtly
inequilateral. Anterior margin rounded, passing gradually imto the convex
ventral margin. Posterior margin subtruncate, higher than the anterior margin.
Umbones prominent, with a faint carma extending to the postero-ventral extremity
and forming the limit of the flattened postero-dorsal area. Margins of valves
serrate.
Ornamentation consists of numerous small, shehtly-raised radial ribs separated
by narrow grooves; anteriorly the ribs become gradually smaller and are absent
or indistinct near the antero-dorsal margin; on the postero-dorsal area the ribs
are stronger and the grooves broader than elsewhere, and the anterior margins of
these ribs are sometimes serrate. In well-preserved specimens faint concentric
linear ridges are seen.
Measurements -
(1) (2) (3) (4) (5)
Lemeth— =~ 17 Lovo & 14-2 14. 10°5 mm.
Height . 18 ; LG 15 145. dT par oa
(1—5) Crackers, Atherfield.
Affinities.—See C. Cottaldinum (p. 203).
In form (. [bbetsoni resembles CO. Raulinianunm, VOrbigny,'’ but the latter is
distinguished by its broader grooves which bear pointed projections.”
In the specimens figured by Pictet and Renevier from the Aptian of the Perte
du Rhéne the umbones are more prominent than in English examples of
C. Ibbetsoni, but Pictet and Campiche, who were able to compare examples from
Atherfield with those obtained from the Perte du Rhone, felt no doubt as to
their specific identity.
Type.—From Atherfield, in the Museum of the Geological Society.
Distribution.—Lower Greensand (Crackers) of Atherfield.
1 «Pal. Frang. Terr. Crét.,’ vol. iti (1844), p. 25, pl. cexlii, figs. 7—11.
2 C. Raulinianum is recorded by Morris from the Lower Greensand of the Isle of Wight, and by
Topley from the Atherfield Beds of Peasmarsh and Shalford. Specimens from the Atherfield Clay
were referred to C. subhillanum, Leymerie, by Forbes, but that identification was regarded as doubtful
by Pictet and Campiche ; the form of the shell cannot be made out satisfactorily, but the ornamenta-
tion resembles that of C. Ibbetsoni. An internal cast from the Lower Greensand of Upware was
referred with doubt to C. subhillanum by W. Keeping (‘ Foss. Neoc. Upware and Brickhill,’ 1883,
p. 119) ; the specimen is now in the Sedgewick Museum, Cambridge, and seems to me insufficient
for determination. A specimen with radial ribs, from the Lower Greensand of Maidstone, was named
Cardium Benstedi by Forbes, but was too imperfect for figuring; the type is in the Museum of the
Geological Society (No. 2124) ; no other specimen has been seen. Forbes, ‘ Quart. Journ. Geol. Soc.,’.
vol. 1 (1845), p. 244; Pictet and Campiche, ‘ Foss. Terr. Crét. Ste. Croix’ (‘ Matér. Pal. Suisse,’ ser 4,
1866), p. 267.
CARDIUM. 203
Carpium Corraupinum, d Orbigny, 1844. Plate XXXII, fig. 11 a—e.
1844. Carprum Corratpinum, A. d’Orbigny. Pal. Franc. Terr. Crét., vol. in,
p. 22, pl. cexlu, figs. 1—4.
1850. — — @’ Orbigny. Prodr. de Pal., vol. ii, p. 79.
1866. — — F. J. Pictet and G. Campiche. Terr. Crét. Ste.
Croix (Matér. Pal. Suisse, ser. 4),
p. 246, pl. exviu, figs. 1, 2.
1871. — — F. Stoliczka. Paleont. Indica, Cret. Fauna S.
India, vol. i, p. 212.
1883. -- - W. Keeping. Foss., etc., Neoc. Upware and Brick-
hill, p. 118, pl. vi, fig. 4.
1884. — — O. Weerth. Die Fauna des Neocom. im Teutoburg.
Walde (Paleont. Abhandl., vol. ii),
p. 44, pl. ix, fig. 3.
— — OERLINGHUSANUM, Weerth. Ihbid., p. 44, pl. ix, fig. 4.
1895. — Corraupinum, G. Maas. Zeitschr. der deutsch. geol. Gesellsch.,
vol. xlvii, p. 263, pl. vii, figs. 2, 3.
1900. — — A. Wollemann. Die Biv. u. Gastrop. d. deutsch. u.
holland. Neocoms (Abhandl. d.
k. preussisch. geol. Land., Nn. F.,
pt. 31), p. 107.
Description.—Shell oval, inflated, shgehtly inequilateral, rather higher than long.
aterior and ventral mareins rounded. sterior mare ‘e or less tru 4
Ant 1 tral margins rounded. Posterior margin more or less truncated
Umbones rather high, sharp, curved inward and forward, with an indistinct carina.
Uml ther high, sl , curved inward and forward, with an indistinct ca
Ornamentation consists of numerous, small, regular, radial ribs, which are
rather more prominent on the posterior area than on the sides of the shell.
Measurements :
Length : a: : : 2Ay mam
Height : : : 23 Ome.
Upware.
Affiiities.—This species closely resembles C. Lbbetsoni, but differs in having the
posterior area less flattened and the outline of the shell more rounded. ‘The
English specimens of C. Cottaldinum are larger than those of C. Lbbetsomi, but are
not sufficiently numerous or well-preserved for exact comparison.
In C. Cottaldinum the shellis relatively higher than in CU. Voltzt, Leymerie.'
CU. landeronense, de Loriol,” appears to be closely related to CU. Cottaldiuwm.
Type.—D’Orbigny’s specimens came from the Neocomian of Wassy (Haute-
! For references see Pictet and Campiche, ‘Terr. Crét. Ste. Croix’ (‘ Matér. Pal. Suisse,’ ser. 4,
1866), p. 247. .
> P. de Loriol and V. Gilliéron, ‘ Urgonien Infér, de Landeron’ (1869), p. 14, pl. i, fig. 12.
204 CRETACKOUS LAMELLIBRANCHIA.
Marne), Brillon (Meuse), St. Sauveur and Auxerre (Yonne). The specimens
figured by Keeping are in the Sedgwick Museum.
Distribution.—Lower Greensand of Upware.!
Carpium, sp. Plate XXXII, fig. 12 a, b.
Internal casts of a globose form of Cardium occur in the Lower Greensand of
Seend and Faringdon. On one specimen (No. 21272, Museum of Practical
Geology) a portion of the shell is preserved, and its ornamentation resembles that
of CO. Ibbetsoni and C. Cottaldinum. The form of the shell seems to be rather more
like that of OC. Lbbetsont than of C. Cottaldinwm.
CaRDIUM, spp.
Specimens of Cardiwm from the Cenomanian of Dunscombe, South Devon, were
referred by C. J. A. Meyer to C. alternans, Reuss, and C. alutacewm, Goldfuss.
Better preserved specimens are needed before these determinations can be con-
firmed.
CARDIUM TURONIENSE, Woods, 1897. Plate XXXII, figs. 13—15.
1897. Carprum TURONIENSE, H. Woods. Quart. Journ. Geol. Soc., vol. liii, p. 389,
pl. xxvii, figs. 20—22.
Description.—Shell small, oval, higher than long, inequilateral, much inflated,
postero-dorsal part compressed. Umbones prominent, with a considerable anterior
curvature. Ornamentation consists of many strong radial ribs. Length, 6 mm.;
height, 7 mm.
Affinities.—This species shows some resemblance to CU. cenomanense, d’Orbigny,”
but is more inequilateral owing to the much greater curvature of the umbones ;
also the ribs are less numerous, and tubercles appear to be absent from the
grooves.
T'ype.—In the Sedgwick Museum, Cambridge.
Distribution.—Chalk Rock of Cuckhamsley.
! Some small specimens found in the Ferruginous Sands of Shanklin may perhaps be referred to
C. Cottaldinum, but they are too imperfectly preserved for exact determination.
2 «Pal. Frang. Terr. Crét.,’ vol. iii (1844), p. 37, pl. cexlix, figs. 5—9.
CARDIUM. 205
Carpium, sp. Plate XXXII, fig. 16 a, b.
1897. Carpium, sp. cf. cenomanensn, H, Woods. Quart. Journ. Geol. Soc., vol.
hii, p. 389, pl. xxvii, figs. 23, 24.
Internal casts, similar in form to C. cenomanense, @Orbigny, are found in the
Chalk Rock of Cuckhamsley. A part of the shell is imperfectly preserved on one
specimen and is ornamented with fine radial ribs. A cast measures: height, 8 mm. ;
length, 8 mm.; thickness, 7°5 mm.
Carpium, sp. Plate XXXII, fig. 17 a—e.
''wo internal casts from the Chalk of Norwich (one of which was found by the
late T. G. Bayfield) are inthe British Museum (Nos. 19448, 420105). The shell
is much inflated, so that the height and thickness are approximately equal; the
height is considerably greater than the length. The umbones are prominent.
‘he postero-dorsal part of the shell is flattened and shows indications of fine radial
ribs.
This species shows some resemblance to CU. ventiicosum, d’Orbigny,' but is
relatively higher.
Sub-genus—GRranocarpium, W. MW. Gabb, 1869.
(“ Geol. Survey California,” ‘ Paleont.,’ vol. 11, p. 266.)
CaRDIUM (GRANOCARDIUM) PROBOSCIDEUM, Sowerby, 1817. Plate XXXII, figs. 18, 19;
Plate XXXITI, figs. 1—3.
1816. Carprira tuBERcuLATA, J. Sowerby. Min. Conch., vol. ii, p. 97, pl. exliii.
(Non Cardium tuberculatum, Linnzus).
1817. Carpium prososcrpEum, J. Sowerby. Min. Conch., vol. ii, p. 127, pl. clvi,
fig. 1.
1835. — Gentranum, J. de UC. Sowerby. Ibid. (Systematical Index), vol. vi,
p- 242.
1854. — proBoscipEuM, J. Morris. Cat. Brit. Foss., ed. 2, p. 193.
— — Genrianum, Morris. Ibid., p. 192.
1866. -~ pRoBoscipEuM, F. J. Pictet and G. Campiche. Foss. Terr. Crét.
Ste. Croix (Matér. Pal. Suisse,
ser. 4), p. 269.
1 C. ventricoswm is recorded from the Upper Greensand (zone of Pecten asper) of Lulworth by
Barrois (‘ Terr. Crét. Supér. de ? Angleterre et de lIrelande,’ 1876. p. 92). I have not seen any
English example of that species.
27
206 CRETACEOUS LAMELLIBRANCHIA.
1866. Carptum Gentianum, Pictet and Campiche. Ibid., p. 269.
1871. — proposcipEUM, I’. Stoliczka. Palweont. Indica, Cret. Fauna 8.
India, vol. ii, p. 213 (Acantho-
cardium).
— GentranuM, Stoliczka. Ibid., p. 213 (Acanthocardium).
1882. — progoscipEuM, P. de Loriol, Gault de Cosne, p. 91, pl. xi, fig. 4.
1900. — Genrianum, LH. T. Newton and A. J. Jukes-Browne. In Jukes-
Browne, Cret. Rocks of Britain,
vol. i, p. 448.
Description.—Shell stout, very convex, oval, higher than long, shghtly mequi-
lateral. Anterior margin rounded; posterior margin truncated, forming an
angle with the postero-dorsal margin. Umbones prominent.
Ornamentation consists of radial ribs separated by narrow grooves; the
stronger ribs bear prominent, angular, laterally compressed tooth-like projections,
which may be rather larger near the posterior margin than elsewhere; in the
spaces between the stronger ribs are two (sometimes one or three) smaller ribs with
similar but smaller tooth-like projections. Margins of valves toothed.
Measurements -
(1) (2) (3) (4) (5)
Length 63 59 58 57 47 mm.
Height 74 5 70 ‘ 68 : 65 : o4 ,,
(1—5) Blackdown.
Affinities —A form from the Cenomanian was referred by dOrbigny to
U. productum, Sowerby,' the type of which comes from the Senonian of Gosau.
This identification has been accepted by Zittel, Holzapfel and others, but not by
Pictet and Campiche, and de Loriol. The specimen figured by d’Orbigny? is
probably an example of CO. proboscidewm, Sowerby, and differs from C. productum
in the distinct differentiation of the ribs into a larger series separated by smaller
series.
The differences between OC. Gentianwm and C. proboscideum seem to be due
entirely to their different modes of preservation. The former is found in the
Upper Greensand of Devizes and Ventnor; the shell is absent, but the sand which
filled the interior of the shell now forms a natural cast of the exterior, showing
more or less imperfectly the character of the ornamentation; usually the spines
are represented by stumps only or are almost completely obliterated. In these
specimens the original form of the shell has been more or less considerably
1 «Trans. Geol. Soc.,’ ser. 2, vol. 111 (1832), p. 417, pl. xxxix, fig. 15; Goldfuss, ‘ Petref. Germ.,’
vol. ii (1837), p. 221, pl. exliv, fig. 7; Zittel, ‘ Bivalv. d. Gosaugeb.,’ pt. i (1864), p. 37, pl. vi, fig. 1;
Holzapfel, ‘‘ Die Mollusk. Aachen. Kreide ” (‘ Paleontographica,’ vol. xxxv), p. 179, pl. xvii, figs. 1—5 ;
G. Miller, ‘ Mollusk. d. Untersen. v. Braunschweig u. Ilsede’ (1898), p. 63, pl. ix, figs. 18, 14.
2 «Pal. Frang. Terr. Crét.,’ vol. iii (1844), p. 31, pl cexlvii; Guéranger, ‘ Album Paléont. de la
Sarthe’ (1867), p. 15, pl. xx, figs. 8—10.
TOUCASIA. 207
modified by pressure. On the other hand the shell in C. proboscidewm, from
Blackdown, is replaced by silica, so that both its ornamentation and original shape
are perfectly preserved.
French examples were identified by d’Orbigny! with this species, for which he
proposed the name Cardiwm Moutonianum since the specific name (tuberculata)
under which Sowerby originally described the species had already been used.
Sowerby, however, in the index at the end of vol. vi of the ‘ Mineral Conchology,’
had already substituted Gentianwm for the name which he originally used. I have
not seen any specimen of CU. Moutonianwm, and am unable to say whether or not it
is really identical with C. Gentianum, but m d’Orbigny’s figures the difference in
the sizes of the ribs and tubercles is seen on the anterior and posterior parts of
the shell only.
C. Carolinum, VOrbigny,” and C. inequicostatum, Matheron,* are closely related
to, and perhaps identical with, C. proboscidewm.
Types.—C. proboscideum, from the Upper Greensand of Blackdown, and
Cardita tuberculata (Cardium Gentianwm), from the Upper Greensand of Devizes,
are in the British Museum.
Distribution.—Upper Greensand (zone of Schlanbachia rostrata) of Blackdown,
Haldon, Devizes, and Ventnor.
Family—DICERATIDA, Dall.
Genus—Toucasta, H. Munier-Chalmas, 1873.
(‘ Journ. de Conchyl.,’ ser. 3, vol. xxi, p. 74. Douvillé, ‘ Bull. Soc. géol. de France,’ ser. 3, vol. xv,
1887, p. 762.)
Toucasta LonspaLEt (Sowerby), 1836. Plate XXXII, figs. 4—6.
1836. Dicrras Lonspariu, J. de C. Sowerby. Trans. Geol. Soc., ser. 2, vol. iv,
pp. 268, 338, pl. xin, fig. 4.
1850. Caprotina Lonspaui, A. d’Orbigny. Prodr. de Pal., vol. ii, p. 109
(parti).
1854. Diceras Lonsparu, .J. Morris. Cat. Brit. Foss., ed. 2, p. 201.
1855. Requrenta Lonspauer, S. P. Woodward. Quart. Journ. Geol. Soc.,
vol. xi, p. 53, fig. 29.
1871. — Lonspatu, F. Stoliczka. Paleont. Indica, Cret. Fauna
S. India, vol. iu, p. 233.
1 «Pal. France. Terr. Crét.,’ vol. iii (1844), p. 34, pl. cexlviii; and ‘ Prodr. de Pal.,’ vol. 11 (1850),
p. 162.
2 Op. cit. (1844), p. 29, pl. cexlv.
3 «Catal. Foss. des Bouches-du-Rhéne’ (1842), p. 157, pl. xviii, figs. 3, 4.
208 CRETACEOUS LAMELLIBRANCHIA.
Remarks.—The examples of Toucasia Lonsdalei are in the condition of internal
casts in a ferruginous sandstone, so that it is difficult to compare this with other
species. ‘The casts show a considerable amount of variation in form. D’Orbigny,
de Loriol, and Pictet and Campiche included Requienia carinata, Matheron,' from
the Urgonian of Orgon, as a synonym of Sowerby’s Diceras Lonsdalet; but Prof.
Douvillé? and M. Paquier® think that the identity of the two forms is doubtful
and can only be determined by a careful comparison of Hnglish specimens with
internal casts of 7. carinata. Prof. Douvillé* suggests that there is a resemblance
between 7’. Sewnesi and 7’. Lonsdale.
Type.—The type, which is stated to have come from near Calne, cannot now
be found. The specimen from which Woodward’s outline figure was drawn is in
the British Museum, No. 88825.
Distribution.—Lower Greensand of Stock Orchard, south of Calne. Recorded
by Morris from Lockswell Heath, south-west of Calne.
Familyj—MONOPLEURIDA, Fischer.
Genus—GyropleurA, H. Dowvillé, 1887.
(‘ Bull. Soc. géol. de France,’ ser. 3, vol. xv, p. 768.)
GYROPLEURA CorNucoPIm (d’Orbigny), 1847. Plate XX XIII, fig. 7 a, b.
1847. CHama cornucopia, A. d’Orbigny. Pal. Franc. Terr. Crét., vol. ii, p. 689,
pl. eccelxiv, figs. 3—7.
1850. a — d’ Orbigny. Prodr. de Pal., vol. 11, p. 170.
1868. — — F. J. Pictet and G. Campiche. Terr. Crét. de Ste. Croix
: (Matér. Pal. Suisse, ser. 5), p. 7.
1871. — — F. Stoliczka. Paleont. Indica, Cret. Fauna S. India,
vol. ii, p. 234.
1887, GyYROPLEURA — H. Douvillé. Bull. Soc. géol. de France, ser. 3, vol.
KVP: (Cl, es 3
Remarks.—Two specimens from the Chloritic Marl of Dorset agree m form
with examples of G. cornucopiex from the Cenomanian of Rouen (the locality
1 «Catal. Foss. des Bouches-du-Rhone’ (1842), p. 104, pl. u, figs. 1,2; Caprotina Lonsdalii,
d’Orbigny, ‘Ann. Sci. Nat. Zool.,’ ser. 2, vol. xvii (1842), p. 180; Requienia Lonsdalii, VOrbigny,
‘Pal. Franc. Terr. Crét.,’ vol. iv (1850), p. 248, pls. dixxvi, dlxxvii; Caprotina Lonsdalii, de Loriol, in
Favre, ‘ Rech. géol. dans Savoie,’ vol. i (1867), p. 386, pl. C, fig. 22; Requienia Lonsdalii, Pictet and
Campiche, ‘Terr. Crét. Ste. Croix’ (‘ Mater. Pal. Suisse,’ ser. 5, 1868), p. 14, pl. elxi.
2 «Bull. Soe. géol. de France,’ ser. 3, vol. xvii (1889), p. 630.
3 “Les Rudistes Urgoniens,’ I (‘ Mém. Soc. géol. de France,’ Paléont. XI, 1903), p. 41.
* Op. cit., pe 632.
GYROPLEURA. . 209
of the type) and with d’Orbigny’s figs. 4 and 5. The ornamentation in this
species is imperfectly known; most of the examples from Rouen are either
internal casts or have only portions of the shell present, on which the orna-
mentation is rather indistinct. In one specimen from Dorset part of the shell
of the fixed valve is preserved; the radial ribs are not so prominent as in
G. inequirostrata, but concentric lamelle are distinct.
Distribution.—Chloritic Marl] of Melbury Park and Chaldon, Dorset. Recorded
by Jukes-Browne from the base of the Lower Chalk of Chard and Maiden
Newton.
GYROPLEURA INEQUIROSTRATA (Woodward), 1833. Plate XXXIII, figs. 8—13.
1833. Drceras nequrirostratus, S. Woodward. Geol. Norfolk, p. 47, pl. v, fig. 22.
1854. CHama rnm/qurrostraTa, J. Morris. Cat. Brit. Foss., ed. 2, p. 194.
Description.—Shell much inflated. Right valve large, oval, attached by a
considerable portion of the anterior side; umbo prominent, poimted, imcurved
anteriorly. Left valve capuliform, with the umbo near the hinge-margin.
Ornamentation consists of strong, lamellar radial ribs, which are undulose
where they cross growth-rings. The ribs have strongly serrate summits and
are separated by rather broad, flat, smooth interspaces; sometimes the serrations
are replaced by numerous transverse, scale-like structures. Near the fixed part
of the right valve the ribs are more numerous than on the flank.
Measurements of fixed value :
(1) (2) (3) (4)
Length . . 22 : 19 16 : 14 mm.
Height . 28 26 ; 20 1S) %5
(1—4) Norwich.
Affinities. —G. ciplyana (de Ryckholt),' from Ciply, differs from this species
in having the ribs more widely separated and in the presence of small ribs in
the interspaces and on the sides of the main ribs. G. russiensis (d’Orbigny)”
resembles closely G. inequirostrata and was regarded by Morris as a synonym of
the latter, but it possesses small ribs on the sides of the main ribs.*
1 «Mélanges Paléont.,’ pt. ii (1851), p. 179, pl. xu, figs. 12, 13; Douvillé, ‘Bull. Soc. géol. de
France,’ ser. 3, vol. xv (1887), p. 744, pl. xxviii, fig. 11; Holzapfel, ‘ Mollusk. Aachen. Kreide’ (1889),
p- 189, pl. xix, figs. 5, 6; Wollemann, ‘ Fauna d. Liineburg. Kreide’ (1902), p. 75, pl. ui, figs. 5, 6.
2 Murchison, de Verneuil, and de Keyserling, ‘ Géol. de la Russie,’ vol. 11 (1845), p. 496, pl. xl,
figs. 831—33 ; Douvillé, ‘ Bull. Soc. géol. de France,’ ser. 11, vol. xv (1887), p. 775, pl. xxviii, fig. 13.
3G. Miinsteri (v. Hagenow) is probably related to G. inequirostrata, See Ravn, ‘ Mollusk. i
Danmarks Kreidtafl. I, Lamellibr.’ (1902), p. 126, pl. iv, figs. 10, 11.
210 CRETACEOUS LAMELLIBRANCHIA.
T'ype.—From Norwich; in the British Museum.
Distribution. —Upper Chalk (zone of Belemnitella mucronata) of Norwich.
GYROPLEURA, sp. Plate XXXIV, fig. 1 a—d.
Description.—Right valve inflated, attached by a large portion of the dorsal
surface. Left valve convex, subquadrate, with a poimted and incurved umbo.
Right valve ornamented with numerous, small radial ribs which bear transverse
nodes or scales. Left valve with relatively few, stout ribs bearing strong, some-
what irregular, transverse scales or lappet-like projections.
Affinities.—The ornamentation on the right valve is finer and that on the left
valve coarser than in G. cenomanensis (d’Orbigny') ; also the transverse ornamenta-
tion of the ribs is much coarser and less regular.”
Remarks.—The portion of the right valve which was attached includes the
umbo and the neighbouring parts, whereas in most examples of Gyropleura only
the part in front of the umbo is attached. The size of the area which was attached
is larger than usual, but m other species it is seen that that area varies considerably
in size in different examples.’
The only specimen seen was collected by Mr. Francis R. B. Williams.
Distribution.—Upper Chalk (zone of Actinocamar quadratus) near the groyne
at Seaford.
Family—CORBULIDAS, Fleming.
Genus—Corbuta, J. G. Bruguiere, 1797.
(‘Encye. Mé¢th.,’ Tabl. Vers., pl. 230.)
Corpunta ancuLata (Phillips), 1829. Plate XXXIV, figs. 2—5.
1829. Isocarpra ancunata, J. Phillips. Geol. Yorks., p. 94, pl. ii, figs. 20, 21
(ed. 3, 1875, p. 252).
1841. — — F. A. Rimer. Die Verstein. d. nord - deutsch.
Kreidegeb., p. 70.
1854. — — J. Morris. Cat. Brit. Foss., ed. 2, p. 204.
1 «Pal. Frang. Terr. Crét.,’ vol. iv (1850), p. 261, pl. dxcv, figs. 1—4.
2 Douvillé, ‘Bull. Soc. géol. de France,’ ser. 3, vol. xv (1887), p. 771, pl. xxviii, fig. 7.
’ In a specimen figured by Griepenkerl the surface of attachment is unusually large; ‘Senon v.
Konigslutter’ (‘ Palzont. Abhandl.,’ v, 1889), pl. vii, fig. 3.
CORBULA. 211
1865. Isocarpia? aneutara, IJ. Pictet and G. Campiche. Foss. Terr. Crét. Ste.
Croix (Matér, Pal. Suisse,
ser. 4), p. 240.
1871. Isocarpra anauuata, I. Stoliczka. Paleont. Indica, Cret. Fauna S. India,
vol. i, p. 194,
1877. Isocarpra? aneunata, G. Bohm. Zeitschr. d. deutsch. geol. Gesellsch.,
vol. xxix, p. 24].
1889. Isocarpia anauLata, G. W. Lamplugh. Quart. Journ. Geol. Soc., vol. xlv,
p. 616.
1900. — _ A. Wollemann. Die Biv. u. Gastrop. d. deutsch. u.
hollind. Neocoms (Abhandl. d. k.
preussisch. geol. Land., N. F., pt.
31), p. 114.
1905. Corsuta (Isocarp1a) anautata, LH. Harbort. Fauna d. Schaumberg-Lippe-
schen Kreidemulde (Ibid.,
pt. 45), p. 81.
1906. Isocarpra aneuLata, A. Wollemann. Die Biv. u. Gastrop. nord-deutsch.
Gaults (Jahrb. d. k. preussisch.
geol. Land., fiir 1906, vol. xxvii),
p. acd.
Description.—Shell with sub-quadrate outline, rounded, occasionally sub-
triangular, very convex, equivalve, more or less considerably inequilateral ; length
ereater than height. Anterior part produced, rounded; ventral margin shghtly
curved; posterior margin truncate, slightly convex, somewhat oblique, forming
angles with the ventral and dorsal margins. Postero-dorsal margin sloping
ventrally. Umbones moderately large, curved inward and more or less considerably
forward, with a carina extending to the postero-ventral angle, cutting off a large,
flattened postero-dorsal area. The part of the valve in front of the carina is
regularly convex. Lunular region depressed.
Ornamentation consists of fine concentric strie.
Measurements :
(1) (2) (3) (4) (5) (6) (7)
Length . 7:1 6°8 6:2 6 6:0 = Jo10) 2) Aro ami:
Height . 60 . 55 DO! Uae Or. ee gs Alin eet O ee.
(1—7) Speeton.
Affinities —This species shows some resemblance to C. gaultina (see p. 214), but
is more nearly quadrate in outline, relatively longer, of larger size, and without
distinct ribs.
C. angulata is fairly common in the Speeton Clay, but no specimen showing the
hinge appears to have been found, so that the generic position assigned to this
species by Philips was presumably based on the external character of the shell.
Pictet and Campiche thought that it probably belonged to Cyprina. Wollemann
states that it is most lkely a Oorbula, and Harbort, who has seen the hinge,
212 CRETACEOUS LAMELLIBRANCHIA.
definitely refers it to that genus; if this view of its position is confirmed it will be
necessary to substitute a new name, since angulata had been previously used by
Lamarck for a species of Corbula from the Kocene.
Distribution.—Speeton Clay (zones of Belemuites jaculum and B. brunsvicensis)
of Speeton.'
CorsuLa striatuta, Sowerby, 1827. Plate XXXIV, figs. 6—12.
1827. CorsuLa srriatuLa, J. de C. Sowerby. Min. Conch., vol. vi, p. 189, pl.
dlxxui, figs. 2, 3.
1846. — — A, d’Orbigny. Pal, Franc. Terr. Crét., vol. ili, p. 459,
pl. ceclxxxvii, figs. JI—13.
1850. = — A. @Orbigny. Prodr. de Pal., vol. u, p. 118.
1854. _- — J. Morris. Cat. Brit. Foss., ed. 2, p. 196.
1858. = — FJ. Pictet and HE. Renevier. Foss. Terr. Aptien (Matcr.
Pal, Suisse, ser. 1), p. 176.
1864. — — EF. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste.
Croix (Matér. Pal. Suisse, ser. 4),
p- 36.
1870. — — F. Stoliczka. Paleont. Indica, Cret. Fauna §8. India,
vol, i, p. 40.
1895. — =: G. Maas. Geitschr, der deutsch. geol. Gesellsch., vol.
xlvii, p. 257.
= = L&vIs, Maas. Ibid., p. 257.
1900. — sTRIATULA, A. Wollemann. Die Biv. u. Gastrop. d. deutsch. u.
hollind. Neocoms (Abhandl. d. k.
preussisch. geol. Land., N. F., pt.
31), p. 144.
Non 1840. — — A. Goldfuss. Petref. Germ., vol. 11,p.251, pl. cli, fig. 16
(C. substriatula, VOrbigny, 1850).
— 1847. — — J. Miller. Petref. der Aachen. Kreidef., pt. 1, p. 25,
pl. ui, fig. 8.
— 1854. — — A.d@Archiac. Bull. Soc. géol. de France, ser. 2, vol. xi,
p. 209, pl. iv, figs. 14, 15.
— 1858. _ — J. Vilanova-y-Piera. Mem. geog.-agric. de Castellon,
pl. i, fig. 14.
— 1867. —- — O. Fraas. Aus dem Orient, p. 92.
— 1870. — — H. Credner. Zeitschr. der deutsch. geol. Gesellsch.,
vol. xxii, p. 236.
1 The type of Corbula punctum, Phillips, from Speeton, cannot be found, and I have not seen any
specimen which could be satisfactorily identified with that species. Phillips, ‘ Geol. Yorks.’ (1829),
p. 122, pl. ii, fig. 6.
CORBULA. 213
Non 1885. CorBULAMELLA STRIATULA, J. Bohm. Verhandl. d. nat. Vereines d. preuss.
Rheinl., vol. xlii, p. 144.
— 1887. — — F. Frech. Geitschr. d. deutsch. geol. Gesellsch.,
vol. xxxix, p. 173, pl. xii, figs. 5—8.
— 1888. = — G. Miller. Jahrb. d.k. preussisch. geol. Land.,
fiir 1887, p. 436.
1889. CorBuLa sTRIATULA, O. Griepenkerl. Senon. v. Konigslutter (Palezont.
Abhandl., vol. iv), p. 69.
1897. == = A. Fritsch. Stud. im Gebiete der bohm. Kreide-
format., vi, Chlomek. Schicht., p. 64,
fig. 83.
— 1901. CorspuLametia striatuLa, F. Sturm. Jahrb. d. k. preussisch. geol. Land.,
fir 1900, vol. xxi, p. 88.
Description.—Shell ovate, usually much inflated, produced and _ pointed
posteriorly, inequilateral, slightly mequivalve. Anterior and ventral margins
rounded. Posterior margin short, obliquely truncated. Umbones broad, strongly
incurved, with a carina extending to the postero-ventral angle and cutting off
a flattened postero-dorsal area. Ornamentation consists of numerous concentric
ribs which extend on to the postero-dorsal area, where they are narrower and more
distinct.
Measurements :
(1) (2) (3)
Length ; Onn ; 6:0 E 5°5 mm.
Height 5:0 : 4:2 : Ar) ,,
(1) Atherfield Beds, East Shalford ; (2, 3) Crackers, Atherfield.
Affinities —This species is distinguished from C. neocomiensis, d’Orbigny,' by
the smaller and more pointed posterior end. It differs from C. substriatula in being
less inequivalve and in possessing a distinct carma. Wollemann considers that
QO. levis, Maas, is identical with C. striatula. Another form which appears to be
closely allied is C. neverisensis, de Loriol,” from the Gault of Cosne.
Remariss.—This species varies considerably in convexity and in relative length
and height. The shorter, more globose, and more distinctly rostrate forms agree
with the type. The more elongate and less convex forms are not so numerous,
and although differing considerably in shape from the globose forms, yet they
agree with them in other respects and do not appear to be specifically distinct.
Specimens from the Lower Greensand of Punfield resemble C. striatula, but
possess stronger concentric ribs—in some cases, as in the example figured (Plate
XXXIV, fig. 13), the ribs are considerably stronger, but in others the difference
is not so great.
1 «Pal. Franc. Terr. Crét.,’ vol. iti (1846), p. 457, pl. ecelxxxvii, figs. 3—5, and ‘ Prodr. de Pal.,’
vol. ii (1850), p. 76.
2 «Gault de Cosne’ (1882), p. 43, pl. v, figs. 23—25.
28
214. CRETACEOUS LAMELLIBRANCHIA.
Type.—Internal casts from the Hythe Beds of Pulborough, in the British
Museum.
Distribution.—Lower Greensand: Crackers of Atherfield. Recorded by Fitton
from the Perna-bed, Atherfield Clay, and Beds VI—IX, XIII, XIV near Atherfield.
Ferruginous Sands of Shankhn. Atherfield Beds of Peasmarsh, Hast Shalford
and Sevenoaks. Hythe Beds of Pulborough. Folkestone Beds of Folkestone.
CorpuLa GAuLTINA, Pictet and Campiche, 1864. Plate XXXIV, figs. 14—16.
1864. CorBuLa GauLTina, F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste.
Croix (Matér. Pal. Suisse, ser. 4),
p- 34, pl. ec, figs. 3, 4.
1870. — — F. Stoliczka. WPaleont. Indica, Cret. Fauna 8. India,
vol. in, p. 40.
Description.—Shell subtriangular, rounded, inflated, shghtly imequivalve, a
httle longer than high, moderately inequilateral. Anterior margin rounded.
Posterior margin subtruncate, oblique. Umbones prominent, rather high, curved
forward, with an inconspicuous carina cutting off a concave postero-dorsal area.
Ornamentation consists of small, concentric ribs.
Measurements :
(1) (2) (3) (4)
Length ; 55 : 5:0 : 4c 6 4-0 mim.
Height : 50) ' Avd é 4-0 . 310°.
(1—4) Gault, Folkestone.
Affinities.—In this species the shell is relatively shorter and more inflated than
in C. elegantula, VOrbigny.’
CO. gaultina may perhaps be, as was pointed out by Pictet and Campiche,
identical with CO. socialis, d’Orbigny,” of which no sufficient diagnosis has been
given.
Remarks.—Numerous individuals of this species are found close together in
groups. When the surface of the shell is not perfectly preserved the ribs become
indistinct.
Type.—From the Gault of Folkestone.
Distribution.—Lower Gault (Bed 2) of Folkestone.
1 «Pal. France. Terr. Crét.,’ vol. ii (1846), p. 460, pl. ecclxxxviii, figs. 14—17.
» «Prodr. de Pal.,’ vol. i1 (1850), p. 136.
CORBULA. 215
CorBuLa TRUNCATA, Sowerby, 1836. Plate XXXIV, figs. 17—22.
1836. CorBuLA TRUNCATA, J. de C. Sowerby. Trans. Geol. Soc., ser. 2, vol. iv,
pp. 240, 341, pl. xvi, fig. 8.
1850. — = A. @Orbigny. Prodr. de Pal., vol. ii, p. 160.
1854. = — J. Morris. Cat. Brit. Foss., ed. 2, p. 196.
1868. — — A. Briart and F. L. Cornet. Meule de Bracquegnies
(Mém. cour. et Mém. des Sav. étrangers, vol. xxxiv),
p- 81, pl. vi, figs. 13—15.
1870. — — F’. Stoliczka. Paleont. Indica, Cret. Fauna S. India,
vol. ii, p. 40.
(7) 1895. — ef. —- E. Tiessen. Zeitschr. d. deutsch. geol. Gesellsch.,
vol. xlvui, p. 485.
Non 1846. — — A. ad Orbigny. Pal. Frang. Terr. Crét., vol. iii, p. 461,
pl. ccelxxxvii, figs. 18—20 (? C.
Goldfussiana, Matheron).
Description.—Shell subquadrate or subtriangular, elongate, rounded, moderately
convex, inequilateral, shghtly mequivalve, considerably longer than high. Anterior
margin well rounded. Ventral margin slightly convex, its posterior part bending
upwards. Posterior margin obliquely truncated, forming an acute angle with the
ventral margin and an obtuse angle with the dorsal margin. Umbones broad,
with a carina extending to the postero-ventral angle and cutting off a flattened or
concave postero-dorsal area. Ornamentation consists of numerous fine, concentric
ribs which are continued on to the postero-dorsal area.
Measurements :
(1) (2) (3) (4)
Length . ; 9 8°5 8 75 mm.
Height . : : O25 6 SAS) Due
(1—4) Blackdown.
Afjiities—This species is less elongate than C. truncata, d@’Orbigny, and is
also distinguished by its concentric ornamentation. It differs from C. lineata,
Miller,’ in the greater obliquity of the posterior margin and in the more numerous
concentric ribs.
Type.—From Blackdown, in the Bristol Museum.
Distribution.—Upper Greensand (zone of Schlenbachia rostrata) of Blackdown.
1 Holzapfel, “Die Mollusk. Aachen. Kreide” (‘ Paleeontographica,’ vol. xxxv, 1889), p. 146, pl. x,
figs. 16—19.
216 CRETACEOUS LAMELLIBRANCHIA.
CorBULA ELEGANS, Sowerby, 1827. Plate XXXIV, figs. 23—28.
1827. CorsuLa ELEGANS, J. de C. Sowerby. Min. Conch., vol. vi, p. 139, pl. d1xxii,
fig. 1.
1850. _ os A. dOrbigny. Prodr. de Pal., vol. 11, p. 160.
1854. a a J. Morris. Cat. Brit. Foss., ed. 2, p. 195.
? 1867. = — ?, E. Guéranger. Album Paléont. de la Sarthe, p. 12,
pl. xvi, fig. 1.
1870. a — F. Stoliczka. Paleont. Indica, Cret. Fauna S. India,
vol. i, p. 40.
Non 1846. — -- A. @Orbigny. Pal. Franc. Terr. Crét., vol. in, p. 460,
pl. eccelxxxviui, figs. 14—17 (C. elegantula, VOrbigny,
1850).
Pe isl = == ?, A. d@Archiac. Mém. Soc. géol. de France, ser. 2,
vol. 11, p. 302.
Description.—Shell subtrigonal, rounded, very convex, inequivalve, inequi-
lateral, a little longer than high.
Right valve with the anterior part sloping rapidly to the margin; anterior
margin rounded; ventral margin convex, its posterior part curving upwards.
Posterior part produced, compressed, separated from the sides by a groove passing
from the umbo to the postero-ventral angle; on the dorsal side of the groove is a
small carina. Posterior margin truncated, forming approximately a right angle
with the straight postero-dorsal margin. Umbo prominent, sharp, curved con-
siderably inward and somewhat forward. Ornamentation consists of strong,
broad, concentric ribs separated by narrow grooves, except on the postero-dorsal
area, which is nearly smooth.
Left valve smaller, less convex, and with smaller ribs than the right valve.
Postero-dorsal area separated from the side of the valve by a groove or sharp
carina.
Measurements :
(1) (2) (3) (4)
Leneth . ; ; 6 DD 5 4°5 mm.
Height . : 4 Av75 4rd 4A. OF Oe ae
(1—4) Blackdown.
Affinities —This species is distinguished from C. elegantula, dOrbigny, by its
broader concentric ribs and rostrate posterior end. It is less globose, less pointed
posteriorly, and has stronger ribs than C. substriatula, d’ Orbigny.
Type.—From Blackdown, in the British Museum.
Distribution.—Upper Greensand (zone of Schlenbachia rostrata) of Blackdown
and Haldon. Recorded by Price from the Upper and Lower Gault of
Folkestone.
PLATE XXVIII.
Genus—Dosiniopsis, Conrad.
Fias.
1—6. D. subrotunda (Sow.). Upper Greensand, Blackdown. Sedgwick
Museum, Cambridge; except fig. 2, British Museum, No. L17067.
(Pest).
1, 2,6. Right valves.
3. Interior of right valve x 1}.
4, 5. Left valves. 5b, interior of 5a.
7—10. D.caperata (Sow.). Upper Greensand, Blackdown. Sedgwick Museum.
(P. 182).
7,8. Right valves. 76, hinge x 1}.
9,10. Left valves. 10, interior of 10a; 10 c, dorsal view.
Genus—CYPRIMERIA, Conrad.
11—18. C. (Cyclorisma) vectensis (Forbes). Lower Greensand (Crackers),
Atherfield. Sedgwick Museum. (P. 183.)
11,12. Right valves. 116, dorsal view of 11 a.
13, 14. Hinges of right valves. 13, a small specimen x 2.
15,16. Left valves.
17. Hinge of left valve x 14.
18. Internal cast of right valve. Exact horizon not known.
19—23. OC. (Cyclorisma) parva (Sow.). Lower Greensand (Crackers), Atherfield.
Sedgwick Museum. (P. 184.)
19a, right valve; b, dorsal view of both valves.
20. Hinge of right valve x 3.
21—23. Left valves. 216, part of 21 a near the ventral margin x 4.
PALA ONTOGRAPHICAL SOCIETY, I906
Volll PLATE. XxXvill
CRETACEOUS LAMELLIBRANCHIA.
: al
London Stereoscopic Vo.
PLATE XXIX.
CYPRIMERIA (continued).
I—3. ©. (Cyclorisma) parva (Sow.). Lower Greensand (Crackers), Atherfield,
except fig. 8. Sedgwick Museum, Cambridge. (P. 184.)
la, left valve; b, anterior view of the same specimen,
2. Hinge of left valve x 3.
3. Perna-bed, East Shalford. Internal cast of left valve.
4—6. OC. (Cyclorisma) rotomagensis (VOrb.). 4, 5, Chloritie Marl. (P. 186.)
4. Wooleombe. Museum of Practical Geology, No. 18735. Right valve, with
part of the shell preserved.
», Maiden Bradley. Museum of Practical Geology, No. 18746. a, internal
cast of right valve; b, dorsal view of the same specimen.
Ox
5. Cenomanian, Rouen. M. Fortin’s Collection. Left valve with shell
~
preserved.
7—15. C0. (Cyclorisma) fuba (Sow.). Upper Greensand, Blackdown. Sedgwick
Museum, except figs. 11, 14,15. (P. 187.)
7—9. Right valves.
10. Hinge of right valve x 2.
11. Left valve. Museum of Practical Geology, No. 19774.
12. Dorsal view of both valves.
13. Hinge of left valve x 1}.
14. The Type of Venus sublevis, Sow. Bristol Museum. (P. 189.)
15. The Type of Venus immersa, Sow., somewhat crushed. Bristol Museum.
Genus—CLEMENTIA, Gray.
16—18. C. (Plaventia) Ricordeana (VOrb.). Lower Greensand (Perna-bed),
Atherfield. Sedgwick Museum. 16, 17, right valves; 18a, left
valve; b, dorsal view of the same specimen—the lunule is drawn
from another specimen. (P. 189.)
19—26. (©. (Flaventia) ovalis (Sow.). Upper Greensand, Blackdown. Sedgwick
Museum, Cambridge, except figs. 20, 23, 26. (P. 191.)
19—22. Right valves. 20, Museum of Practical Geology, No. 19778.
23. British Museum, No. L19444. Interior of right valve.
24. Hinge of right valve x 1}.
25 a, left valve; b, dorsal view of the same specimen.
“
26. Museum of Practical Geology, No. 19814. Hinge of left valve x 1}.
PALZONTOGRAPHICAL SOCIETY, 1908
CRELACROUS
LAMELLY
BRANCHIA.
Wid AN, IPILINIEE OO
London Stereoscopic Co. Imp.
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PLATE XXX,
Genus—Catuista, Morch.
Figs.
1—6. C. plana (Sow.). Upper Greensand, Blackdown. Sedgwick Museum,
Al onnlawa Pp ”)
Cambridge. (P. 192.)
la, right valve; b, ornamentation on the postero-ventral part x 6.
2. Hinge of right valve. The part anterior to the middle of the anterior pit is
drawn from another specimen.
3—6. Left valves. 306, interior of 3a; 3c, dorsal view of 3a; 4b, anterior view
of 4a.
Genus—Prorocardia, Beyrich.
7. LP. anglica, Woods. Lower Greensand (Crackers), Atherfield. Sedgwick
Museum. a, left valve X 2; b, dorsal view X 1. (P. 194.)
TA. Brock,
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PLATE XXXI.
Prorocarpia (continucd).
anglica, Woods. Lower Greensand (Crackers), Atherfield. Sedgwick
Museum, Cambridge. Right valve. (P. 194.)
spheroidea (Forbes). Lower Greensand (Perna-bed). (P. 195.)
2. Sandown. British Museum, No. L8247. a, left valve; b, dorsal view of the
same specimen. x +4.
3. Atherfield. York Museum. a, left valve; 6, posterior view of the same. x $.
5
sp. Upper Greensand, Haldon. British Museum, No. L17041.
Right valve. (P. 196.)
sp. Speeton Clay (zone of Belemnites lateralis), Speeton. Mr. Lamp-
lugh’s Collection. a, right valve X 2; b, dorsal view of both valves
Kies (P1977)
Hillana (Sow.). Upper Greensand, Blackdown. Sedgwick Museum.
a, left valve; b, posterior view of a; c, part of the posterior area
x 4h (P97)
TA. Brock, del.
PALZ ONTOGRAPHICAL SOCIETY, 1908
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PLATE XXXII.
Provocarpta (continued).
ITillana (Sow.). Upper Greensand, Blackdown. Sedgwick Museum,
Cambridge. (P. 197.)
Left valve.
Right valves.
Interior of left valve.
ox ee GC =
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Hinge of right valve.
Dorsal view of both valves.
Genus—Carpium, Linneus.
Ibbetsoni, Forbes. Lower Greensand (Crackers), Atherfield. Sedg-
wick Museum, Cambridge. (P. 201.)
7a, vight valve; 6, dorsal view of both valves; c, posterior view; d, anterior
view ; e, portion of ornamentation of posterior area x 4; /, ornamentation
near the middle of the ventral border x 4.
8,9. Right valves.
10. Left valve.
. Cottaldinwm, VOrb. Lower Greensand, Upware. Sedgwick Museum.
a, right valve; b, dorsal view of both valves; c¢, posterior view ;
d, ornamentation of posterior area X 4; ¢, ornamentation near the
mid-ventral border X 4. (P. 203.)
. sp. Lower Greensand, Seend. Museum of Practical Geology, No.
21273. a, right valve; b, dorsal view. (P. 204.)
turoniense, Woods. Chalk Rock, Cuckhamsley. Sedgwick Museum.
(P. 204.)
13 a, internal cast of right valve x 1}; b, anterior view of the same x 1}.
14. Internal cast of left valve x 15.
15. Ornamentation drawn from a wax mould of an external cast x 6.
sp. Chalk Rock, Cuckhamsley. Sedgwick Museum. Internal cast.
a, right valve ; b, dorsal view of both valves. (P. 205.)
. sp. Upper Chalk (zone of Beleminitella mucronata), Norwich. British
Museum, No. 19443. Internal cast. a, left valve; b, dorsal view
of both valves; c, posterior view. (P. 205.)
(Granocardium) proboscideum, Sow. Upper Greensand, Blackdown.
Sedgwick Museum. (P. 205.)
18. Right valve. The anterior marginal part is drawn from another specimen.
19. Left valve. Dorsal part decorticated.
PALZONTOGRAPHICAL SOCIETY, 1908
Volll PLATE Xxxlil
=
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CRETACEOUS LAMELLIBRANCHIA.
London Stereoscopic Co. Imp.
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PLATE XXXII.
Carpium (continued).
Fras.
I—3. OC. (Granocardium) proboscideum, Sow. Upper Greensand, Blackdown.
Sedgwick Museum, Cambridge. (P. 205.)
la, right valve; b, anterior view of the same.
2a, interior of left valve; b, dorsal view of the same.
3. Hinge of right valve.
Genus—Toucasts, Munier-Chalmas.
4—6. T'. Lonsdalet (Sow.). Lower Greensand, Stock Orchard, near Calne.
Internal casts. (P. 207.)
4. Both valves. Museum of Practical Geology, No. 22720.
5. Lower valve. Museum of Practical Geology, No. 22721. x +4.
6. Upper valve. British Museum, No. 88825.
Genus—GyYROPLEURA, Douvillé.
4}
G. cornucopie (VOrb.). Chloritic Marl, Melbury Park. Museum of
Practical Geology, No. 22440. a, right valve; 6, posterior view of
both valves. (P. 208.)
8—13. G. inequirostrata (Woodw.). Upper Chalk (zone of Belemnitella mucro-
nata), Norwich. 8—10, British Museum, No. 21002. 11—13,
Norwich Museum. (P. 209.)
8a, right valve; b, posterior view of both valves; c, ornamentation of right
valve x 8.
9a, left valve and umbo of right valve ; b, posterior view of both valves.
10. Ornamentation of right valve near the ventral margin x 12.
11. Right valve. Internal cast.
12. Anterior view of both valves. Internal cast.
13 a, left valve and umbo of right valve; b, posterior view of both valves
Internal cast.
PALZ ONTOGRAPHICAL SOCIETY, i908
Voll PLATE. Xx xill
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CRETACEOUS PAME IED TE 2 AINI@ eis
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14—16.
17—22
23—28
PLATE XXXIV.
GYROPLEURA (continued).
Gi, sp. Upper Chalk (zone of Actinocamaa plenus), Seaford. Mr. F. R. B.
Wilhams’ Collection. a, left valve and umbonal part of right valve ;
b, posterior view of both valves; c, ornamentation of left valve x 3;
d, ornamentation of right valve xX 3. (P. 210.)
Genus—Corsuta, Bruguiere.
C. angulata (Phill.). Speeton Clay, Speeton. 2, 5, Sedgewick Museum ;
Y > >) >] to) )
3, 4, Mr. Lamplugh’s Collection. (P. 210.)
2a, left valve; b, dorsal view of both valves; c, anterior view. x 5.
3, 4. Left valves x 5.
5. Right valve x 5.
. striatula, Sow. Lower Greensand (Atherfield Beds), Hast Shalford ;
except 7 and 12, from the Crackers, Atherfield. Sedgwick Museum.
Keone (e. 2t2)
6—10. Right valves. 9b, dorsal view of 9a.
11 a, left valve; 6, dorsal view of both valves.
S
12. Anterior view of both valves.
ei
VU. sp. Lower Greensand, Punfield. Museum of Practical Geology,
No. 22723. Right valve, the posterior part broken, x 5. (P. 213.)
C. gaultina, Pict. and Camp. Gault, Folkestone. x 5. (P. 214.)
14. Sedgwick Museum. a, right valve; b, dorsal view of both valves; c, anterior
view.
15, 16. Museum of Practical Geology, Nos. 22727, 22728. Left valves.
'. truncata, Sow. Upper Greensand, Blackdown. Sedgwick Museum.
Xo bias)
17—19. Right valves.
20, 21. Left valves. 206, dorsal view of 20a.
22a, posterior view of left valve x 5; b, ornamentation near the middle of the
aad,
~
\
ventral margin x 10.
~
\=2
. elegans, Sow. Upper Greensand, Blackdown. Sedgwick Museum.
x 5. (PB. 216.)
23—26. Right valves.
27. Anterior view of both valves.
28 a, left valve and umbo of right valve; 6, dorsal view of a.
PALZONTOGRAPHICAL SOCIETY, 1908
Volll PLATE X¥X1V
CRETACEOUS LAMELLIBRANCHIA.
London Stereoscopic Co. hr
PALAHONTOGRAPHICAL SOCIETY.
INSTITUTED MDCCCXLVI.
LON DOWN
MDCCCXCI—MDCCCCVIII.
MONOGRAPH OF THE BRITISH FOSSIL ECHINODERMATA FROM
THE CRETACEOUS FORMATIONS.
Vou. I1.—AstTEROIDEA AND OPHIUROIDEA.
Mr. Sladen is the author of pages 1—66, Plates I—XVI, while Mr. Spencer
is the author of the remainder of the Volume. Mr. Spencer desires to express
his indebtedness to Dr. F. A. Bather for much help and advice in his share of
the work.
ORDER OF BINDING AND DATES OF PUBLICATION.
| ISSUED IN VOL. |
Bee | ee SUED IN VO.) pe pareutED
Title-page | res | 1908 | December, 1908
1—28 | [Vin ' ago9 | April, 1891
2966 | IX-XVI 1893 December, 1893
67—90 | XVII-XxvI | 1905 Novemben 1905
Eley, | XOXGV Ali XONGIONG | 1907 December, 1907
133—138 (including Index) _— 1908 | December, 1908
The Plates are intended to be collected and bound at the end of the Volume.
A MONOGRAPH
Beis H FOSSIL
HCHINODERMATA
FROM
THE CRETACKOUS FORMATIONS.
VOLUME SECOND.
Eh ASTRO A AND OPRELUROMDEA’
We PERCY SLADHN, Fils. mes,
AND
WK SPENCER, BAS, EGS:
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PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.
1891—1908.
it
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AS VEO IN OG ROA Po
ON THE
Pee iS ELS O55. I
HCHINODERMATA
FROM
THE CRETACKOUS FORMATIONS.
VOLUME SECOND.
Eb ASE Oma AND OPEN U E.Omp iA.
LENE
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PAI SEB:
Paces 1383—138; TirLE-pacr anp INpDEx.
LON DOW:
PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.
1908.
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PRINTED BY ADLARD AND SON, LONDON AND DORKING.
:
ADDENDA ET CORRIGENDA. 133
almost all Cretaceous Asteroids, and in quite young forms of the order “ Crypto-
zonia,’ the margin of the disc and arms is bordered by specially prominent plates
> The abactinal series are called “ Supero-marginalia,”’ and the
—the “ Marginalia.’
actinal series the “ Infero-marginalia.”
Primary Inter-vadialia.—See Centrale.
fadialia.—Vhe abactinal series of plates along a major radius are called the
‘achalia.
TRadius.—A line drawn from the central point of the disc to an extremity of
the arm is called the “ Major radius,” R.A line drawn from the central point of
the disc to a point half-way between two radu is called the * Minor radius,” vr.
This is sometimes called an “ Jnter-radius.”
Spiie-pits—Depressions in a plate for the articulation of spines (see p. 118).
Ventro-lateralia.—The plates on the actinal surface of the Asteroid excluding
the infero-marginalia and the adambulacralia. In the inter-radial regions these
plates are often rhomboidal. A typical view of an isolated plate of this descrip-
tion is given (Pl. XXIX, fig. 4).
ADDENDA ET CORRIGENDA.
Page 24, line 19, for Schiilze read C. I’. Schulze.
Page 26, Locality, etc., for Upper White Chalk near Norwich read Hard Chalk,
West Norfolk, the precise locality unknown.
Page 67, line 11, for Goniaster compactus read Goniaster (Goniodiscus) compactus,
and omit all reference to Forbes, 1848.
Page 69, line 15, for Stellaster comptoni read Goniaster (Stellaster) Compton.
Page 71, line 4, for Stellaster elegans read Goniaster (Stellaster) elegans.
Page 89, line 8 from end, for Bourguetiocrinus read Bourgueticrinus.
Page 90, last line, for Upper Greensand read Lower Chalk.
Page 95, line 3, for Sladen read Forbes.
Page 95, line 13, for (p. 89) read (p. 89, Pl. XXV, fig. 7).
Page 101, line 9 from end, the first reference should read Opnrura, Lamarch:,
1801. Systeme des Animaux sans Vertebrés, p. 350. The date of the reference
given is 1816.
Page 102, line 12, for 1841 read 1840.
134. FOSSIL ASTEROIDEA.
Page 103, line 10, add cor-anguinwm zone, Northfleet, Kent, and Blandford,
Dorset.
Page 103, line 11, add in synonym: Oputura surrata? Forbes, 1843. Proc.
Geol. Soc., vol. w, p. 254.
Page 103, line 4 from end, for parvisentum read parvisentis.
Page 106, line 7, after #5060 add and M5061; under Locality insert Molhestone.
Page 117, line 12 from end, for M. read Metopaster.
Page 117, line 7 from end, for M. read Mitraster.
Page 117, line 2 from end, for M. read Metopaster.
Page 118, line 3 from top, for M. read Mitraster.
Page 118, line 7 from top, for M. read Metopaster.
Page 118, line 9 from top, for M. read Metopaster.
Page 118, line 12 from top, for M. read Mitraster.
Page 119, line 3 from end, for bipunetatus read bispinosus.
Page 120, line 13 from end, for bipunctatus read bispinosus.
Page 130, table and line 7 from end, for bipunctatus read bispinosus.
Page 121, lnes 2, 4, 6, for S. read Stawranderaster.
Pl. IV, figs. 2—4, for Lower read Upper.
Pl. V, fig. 1, for Tomidaster sulcatus read Calliderma Smithix (see p. 125).
Pl. VU, figs. law and 2a, for ? Nymphaster Coombit read Calliderma Smitha
(see p. 122°
Pl. X, fig. 4, for Metopaster Parkinsow read Metopaster uncatus (see p. 124).
Pl. XIX, fig. 3, for Nymphaster Coombii read Calliderma Sivithix (see p. 122).
Pl. XXI, fig. 2, for Pentagonaster robustus read ? a young form of Pycinaster
angustatus (see p. 95).
Pl. XXIV, fig. 1, for Pentaceros abbreviatus read Hadranderaster abbreviatus
(see p. 125).
Pl. XXV, fig. 2, for Upper Greensand read Lower Chalk.’
Pl. XXV, fig. 6, for Genus ? sp. ? (p. 93) read ? Stauranderaster argus (p. 99).
P]. XXV, fig. 7, for Pentaceros? n. sp. (p. 89) read Pycinaster angustatus
(pp. 89, 95). |
Pl. XXV, fig. 8, for marginal read internal.
Pl. XXVI, fig. 1, for Pentaceros punctatus read Pycinaster senonensis (see p. 95).
Pl. XXVI, fig. 4, for Calliderma mosaicum read Pycinaster angustatus (see
Pp. 99).
Pl. XXVI, fig. 4, for From the Lower Chalk read From the Upper Chath.
Pl. XXVII, fiz. 36, for abactinal read actinal or adoral.
Pl. XXVII, fig. 3c, for side read right side.
' Mr. H. Woods informs me that recently he has been able to match the matrix in which this
rossil is embedded.
ADDENDA. ET CORRIGENDA. 135
PL XXVIL for Ophiura parvisentum read Ophiura parvisentis.
Pl. XXVII, fig. 4, before natural size insert slightly less than.
Pl. XXIX, fig. 12, for Sladen sp. read Sladen.
On all Plates (except XXVI) for Culliderma mosaicum read C. Sinithie (see
p. 122).
On all Plates for Metopaster Bowerbankii, M. Mantelli, M. zonatus, read M.
Parkinson (see p. 124).
On all Plates for Metopaster cingulatus read M. wicatus (see p. 124).
On all Plates for Pentaceros bulbiferus, P. Boysti, P. coronatus, P. bipunctatus,
P. squamatus, P. pistilliferus, P. ocellatus, P. argus, read corresponding species of
Stauranderaster (see p. 125).
On all Plates for Pentagonaster megaloplax, read P. quinqueloba (see p. 108).
Abactinal
Acalia ...
Actinal
Adambulacral plates
Adradialia
Ambulacral
Amphiura
— cretacea
Amphiurid ...
Arthraster
—— cristatus ...
Dixoni
senonensis
Asterias Dunkeri
— _jurensis
— lunatus
— quinqueloba
Schulzii
tabulata
Astrogonium ...
angustatum
Bowerbankii
Coombii
compactum
— Hunteri
— latum ...
= lunatum
Mantelli
— mosaicum
_- Parkinsoni
rectilineum
rugatum
= Smithii
sublunatum
-— uncatum
Ast ropecten
Astropectinida
INDEX.
PAGE
131
100
131
131
131
131
ae SLOG
107; xxviii
106
91, 131
93, 118; xxix
ooo Ml, Wisse seqyatit, sSi0bs
93
109
108
25
107
109
108
24
22
42
15
67
59
12
27
38
9
32 |
32
63
6
51
47
90
90
Calliderma
= latum
~ mosaicum
= Smithie _..
Centrale
Ceelaster Couloni
Comptonia
comptoni
— elegans
Cryptozonia
Cupulaster pauper
Dorigona
Euasteroidea ...
General characteristics
Generic and specific characters
Glossary
Goniaster
= angustatus
Bowerbankii
compactus
— Coombii
— Hunteri
= latus
lunatus
= mammillata
Mantelli
marginatus
mosaicus ...
Parkinsoni
rectilineus
regularis
rugatus
semilunata
PAGE
4, 122, 129
12 Gs sity a
9, 123; v, vi, vil
6, 1155 123% a5 vat
132
109
69
69 ; xvii, Xvill
(Lee xvi
100
109
69
° INDEX.
PAGE
Goniaster Smithii 6
— sublunatus 51
== uncatus 47
Goniodiscus aft 24
— Bowerbankii 42
~ Hunteri 59
~- Mantelli 3
— Parkinsoni 32
— rectilineus 32
== rugatus ... 3)
= sublunatus 51
a= uneatus... 47
Hadranderaster é WD, AKO)
-- abbreviatus... 114, 118, 125
Hosia ... 24,
Key-table 114
Linckia 100
Linckiide 100
Marginalia oe a 132
Metopaster Be 30, 97, 124, 128
— Bowerbankii . 425 xv, XVI
-- cingulatus 533 XIV
— cornutus ... 5 a, UN sayy
— Mantelli a a 38; xii
=== Parlinsoni 31, 114,117, 124; ix—xu,
XV1
= quadratus 97, 118
= sublunatus Bs eee anol
= uneatus Alig, Milisse sei, sony Shy
— zonatus AS 3 xi
Mitraster Dales
— compactus ... . 67, 118; xvi, xxvi
== Hunteri 5); WUE S abs, Salil, Say
— rugatus 63, 118; xvi
Nectophiure ... x Le P06
Nymphaster _ 1A, 73, 94, 122, 129
-— Coombii Wy, WBS abt, \yabl
— marginatus poate WIM oye, yan!
— oligoplax 19, 114, 116; vin
—_ radiatus er Wily 9g xan,
-— rugosus 94, 117; xxix
V7
PAGE
Ogmaster 69
Ophidiaster 100
Ophioglypha ... 101
— bridgerensis 110
== texana ... WI
Ophiolepididie 101
Ophiolepis 101
Ophiotitanos ee SOM
— leevis 105 ; xxvill
— magnus 106 ; xxviii, xxix
— tenuis 104; xxviii
Ophiura 101
— Ja heelivn 103 xxvii
eranulosa 111
— parvisentum 103; xxvil
— pulcherrima 112
— gerrata 102; xxvu
Ophiuroidea 101
Oreaster 76
— Boysii 80
— )ulbiferus Ha
— coronatus 82
—- ocellatus 85
— obtusus 7A.
— pistilliformis 88
— pistilliferus ... 88
Ornament 113
Pedicellarise 114
Pentaceros a 76
= abbreviatus 86, 125; xxiv
— bispinosus Oe 87, 125: xxi
= Boysu 80, 125; xxil, xxii, xxvi
bulbiferus (ily WSS sos FSS, You
= coronatus ep IS Sake, vOun yy Xoo;
== dilatatus 110
os ocellatus ... 85, 125. xxv
= pistilliferus 88, 125; xxv
= punctatus . 88, 95; xxvi
= senonensis 81, 95
a= squamatus Solar xx
Pentacerotidee 76, 99
Pentagonaster 24, 73, 122, 129
== lunatus 25, 116; iw
— megaloplax 27, 108; iv
— obtusus 74, 115; xxii
— quinqueloba 108, 114, 116
21
138 INDEX.
PAGE
Pentagonaster rectilineus —... ae we aaron
_— regularis ott ch 5 oil
~- robustus oe es (BI So:0h
—- semilunatus ... os oo SS
Pentagonasteride —... a. Ga sony, Be
Pentagonasterine ; ie ee a A
Phanerozonia... om ee me ae 3
Phylogeny... 3 ms Ww soe
Primary inter-radialia or oe oglos
Pycinaster... ‘ : By. 95, 131
-- aneustatus 93, 95,119; ix, xxi, xxv,
XXV1
— senonensis 95, 114, 119; xxvi, xxix
Pyenaster ... ee Ne 21, 95
_ angustatus 21, 95; ix, xxi, xxv, xxv
— ChaSSTIS Meee Rt CXR, IIS) s sxx
Radialia =e Be 365 pi we 33
Radius ae se = a 133
Specific and generic characters s pee
Spine-pits —... a a elves
Stauranderaster ie an O30
— argus oe 99; xxv, Xxix
PAGE
Stauranderaster bipunctatus (= bispinosus) 119
-— bispinosus ... aft: me 2
— Boysii ie re 120, 125
— bulbiferus 113,119, 120, 121, 125
= coronatus ... 114, 120, 125
— ocellatus ... ue OAL PAs)
= pistilliferus a 1205 1125
— squamatus ... £ 120, 125
Stellaster ws ee » oY
_- albensis ... Bae - = 102
— Comptoni ... es =a a) 169
-- Coombii ... os? bat pon LL
— elegans. r oy hee. Ol
— Schulzii ; ao OS)
Tomidaster sulcatus ... Se nes eels
Mosia en ~ ae ny. a son
— lunata ... se Fé ast ee 20)
— regularis oa a ae coll
| Ventro-lateralia ie ne. = joe 1G}
|
Zygophiure ... 2 oe aN ae OL
ADLARD AND SON, IMPR., LONDON AND DORKING,
Palxontographical Society, 1908.
A MONOGRAPH
BRITISH CAMBRIAN TRILOBITES.
IPEEEEUP wb AKS McA, BG...
ST. JOHN'S COLLEGE, CAMBRIDGE.
PART EE.
Paces 49—64; Puates V, VI.
LONDON:
PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.
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OROMETOPUS PRANUNTIUS. 49
one quarter the width of the head, bounded by well-defined axial furrows, and in
front by a strong furrow separating it from the frontal limb ; neck-furrow distinct,
but no definite glabellar furrows. Cheeks wide, moderately convex, sometimes with
a prominent ridge extending from the anterior corners of the glabella to the genal
angles; united in front of the glabella by a prominent frontal limb ; occipital
furrows strong; a small lobe separated off from the cheek in the angle between
the axial and the occipital furrows. Hyes crescentic, placed near to the occipital
furrow, and about halfway between the glabella and the external margin. Facial
suture marginal or infra-marginal in front; running nearly straight backwards to
the eye, then outwards to the marginal rim, and finally backwards and a little
inwards to the posterior margin. Margin forming a narrow raised rim, uniform in
width, striated on the doublure. Genal angles produced into long slender spines,
which curve at first a little outwards and then backwards, extending far beyond
the tail.
Thorax of seven, or sometimes fewer, segments, narrowing slightly towards the
posterior extremity. Axis forming nearly one third of the total width in the first
three segments, narrowing posteriorly. Pleure straight, horizontal, grooved, the
first three terminating in blunt points, the rest truncate and apparently bent
downwards at the tips.
Tail wide but very short, forming a flat triangle. Axis narrow, conical,
reaching nearly to the posterior margin, showing traces of four rings. Lateral
lobes flat, with a very faint furrow near the anterior margin. Margin bent down-
wards.
The largest specimens attain a length (exclusive of the genal spines) of nearly 2cm.
This species is closely allied to O. elatifrons, and the differences are probably
even less than they appear at first sight, and are due in part to the less perfect
preservation of the specimens. In the specimen figured the glabella is more
quadrate than in the Shineton form and is not produced posteriorly into a spine,
but it is somewhat flattened by pressure, and other specimens from the same
locality suggest, though they do not prove, that the glabella was not very different
in shape from that of O. elatifrons, and was perhaps produced posteriorly in a
similar fashion. There are, however, other differences which appear to be real.
In O. elatifrons the space in front of the glabella, between it and the raised marginal
rim, 1s concave ; in O. prenuntius it is convex, and is separated from the gelabella
by a distinct furrow. The ridges which run across the cheek from the anterior
corners of the glabella to the genal angles are absent in O. elatifrons, but they are
not always very distinct even in the present species... The genal spines in
1 These ridges are similar to those described and figured by Salter in T'rinucleus gibbsi (Mem.
Geol. Surv., vol. i, p. 319, pl. xii, fig. 10), and, as appears to be the case in that species, are probably
only the result of lateral pressure acting upon a rather abrupt bend.
8
50 BRITISH CAMBRIAN TRILOBITES.
O. prenuntius are longer than in O. elatifrons, and, where they spring from the
cheeks they are often more strongly bent outwards. In both species the number
of thoracic segments may vary, even in forms which in other respects appear to
be adult. In O. prenuntius none of the specimens have more than seven; in
O. elatifrons the few specimens which afford any evidence on this point have either
eight or nine.
The type specimens of Salter’s Ampye prenuntius are unfortunately unknown,
and appear to have been lost; but Salter states that in this form the glabella is
short and not produced to the margin, and there is a narrow convex rim around
the head. In these characters it agrees with Orometopus and differs from the true
Ampyz. The specimens were found at Pen-y-clogwyn, near ‘T'remadoc ; and in the
Jermyn Street Museum there is a specimen from this locality which was labelled
Ampyx but which belongs to the species here described. Further, Mr. Fearnsides
tells me that the beds at Penmorfa, in which his specimens of Orometopus
prenuntius were found, may be traced to Pen-y-clogwyn, where the same horizon
is seen. There is, therefore, very strong presumptive evidence that the species
here described is identical with Salter’s Ampyx prenuitius.
Horizon and Localities—Upper Tremadoc : Pen-y-clogwyn and Penmorfa, near
Tremadoc ; Ceunant-y-garreg-ddu and Amnodd Bwll, Areng. The Amnodd Bwll
specimens occur in material of the same character as the specimens of Shumardia
pusilla var. morvensis from the same locality.
Family OLuNipe.
Genus OLENUS, Dalman emend. Angelin.
The name Olenus was substituted by Dalman for the name Puaradowides
previously proposed by Brongniart, and the species which he enumerates are
nearly the same as those given by the latter author. he only exceptions are
that Dalman places in this genus the Mntomostracites bucephalus of Wahlenberg
and removes the Hntomostracites laciniatus of the same writer. Brongniart’s
genotype was Paradoaides tessim, and when it became necessary to divide the
genus, the name Paradovides was limited to those forms in which the glabella is
swollen in front, while Dalman’s term Olenus was by common consent employed
for those in which the glabella is rectangular or parabolic in outline. Subsequent
discovery showed that even with this hmitation the genus Olenus is too large and
varied to admit of satisfactory definition, and Angelin accordingly restricted it to
forms of the type of Olenus gibbosus and Olenus truncatus. The name, however, is
still very often employed in a wider sense, and the following table by E. Persson’
! Geol. Foren. Stockholm Foérh., vol. xxvi (1904), p. 525.
OLENUS. 51
will be found useful. It shows the distinguishing features of the more important
genera which are commonly included under the name of Olenus sensu lato.
if 8. Acerocare.—Tail entire.
(7. Peltwra.—Tail spined.
(6. Spherophthalmus. — Glabella — con-
I. Inermes.—No cheek-spines
: | siderably higher than the strongly
II. Abruptz.—Cheek- ( (4) Pleurz with _
é arched cheeks.
spines abruptly long spines
5. Ctenopyge.— Fixed cheeks flat, im-
projecting from clined to the glabella.
the outer bor- 4. Leptoplastus.—Cheek - spine _ short,
der of the (b) Pleuree with slightly bent.
cheek short spines Ls. Hurycare.-—Cheek-spine long, broad,
strongly bent.
III. Continue.—Cheek-spines in direct [ 2. Parabolina.—Strong spines to tail.
continuation of the outer margin | 1. Olenus.—Tail entire, or with rudi-
of the cheek | mentary spines.
In the section Abrupte the cheek-spines originate well in front of the posterior
margin and spring abruptly from the outer border of the head, making a distinct
angle with the exterior margin. In the Continue the cheek-spines, as in most
Trilobites, arise at the genal angles, and the outer edge of the spine is the direct
continuation of the outer border of the head.
In Persson’s classification no place is found for Brégeger’s sub-genus Para-
bolinella. It is, however, one of the Continue, and as the tail is without spines it
falls into the same division as Olenus proper. In several other respects it is more
closely connected with Olenus than with Parabolina.
Limiting the genus Olenus to the species similar to Olenus gibbosus it may be
defined as follows:
General form depressed, ovate. Head nearly semi-circular, with the genal
angles produced into spines, which are in direct continuation of the outer margin
of the cheeks. Glabella nearly rectangular, but narrowing slightly towards the
front, with two or three pairs of oblique glabellar furrows. Facial suture running
from the anterior margin backwards to the eye, and thence backwards and out-
wards to the posterior margin, cutting the latter some distance within the genal
angle. KHyes placed shghtly in front of the middle of the cheek, and some
distance from the glabella, connected with the glabella by a distinct ocular ridge.
Thorax of 13—15 segments ; the anterior pleurz facetted, shghtly bent downwards
beyond the fulcrum, the posterior pleurz nearly horizontal, without fulerum or
facet; all the pleurz spined and grooved. ‘Tail small, semi-circular or triangular,
sometimes entire, sometimes with a small spine at the anterior angles.
52 BRITISH CAMBRIAN TRILOBITES.
1. Olenus truncatus (Briimnich). Plate V, figs. 1—’.
1781. Trilobus truncatus, Briinnich, Kong. Dansk. Vidensk. Selsk. Skrift., Nye Samling, Férste Deel,
p. 3d.
1827. ‘Trilobites gibbosus var., Boeck (pars), Mag. for Naturv., 1827, p. 24, fig. 8.
1838. Trilobites gibbosus var., Boeck (pars), Keilhau’s Gea Norv., p. 143.
1843. ? Olenus gibbosus, Burmeister, Organ. d. Trilob., p. 81, pl. i, fig. 9.
1854. Olenus truncatus, Angelin, Pal. Scand., p. 43, pl. xxv, fig. 1.
1857. Olenus gibbosus var., Kjerulf, Geol. d. siidl. Norw., p. 284.
1865. Olenus gibbosus var., Kjerulf, Veiviser ved geol. excursioner i Christiania omegn, p. 2.
1882.? Olenus truncatus, Brogger, Die Silur. Etagen 2 und 3, p. 98, pl. xii, figs. 5, 5 a—e.
Our British specimens of this species being very much compressed and dis-
torted, the following description is based on specimens from Andrarum in Scania.
Head about two and a half or three times as broad as it is long, straight in
front. Glabella narrow, less than the width of the cheeks, short, separated from
the front margin by a space about equal to half its own length, nearly parallel-
sided, truncate in front, with three pairs of eglabellar furrows and a well-marked
occipital furrow. Cheeks wide. LHyes fairly large, crescentic, placed nearly in
the middle of the cheeks, distant from the glabella considerably more than half
the width of the latter, connected with the anterior corner of the glabella by a
straight ocular ridge which runs at right angles to the axis. Facial suture
running slightly outwards from the anterior margin to the eye, and behind the eye
curving rather strongly outwards and meeting the posterior margin some distance
within the genal angle. Free cheeks bent somewhat downwards, with faint
vascular markings which radiate from the eye; the posterior border of the free
cheek not quite in line with that of the fixed cheek but turning shghtly forwards.
Margin narrow. Genal spines short, directed outwards.
Thorax of thirteen segments, narrowing backwards from about the seventh
or eighth segment. Axis a little wider than the pleurz. Pleurze straight, in the
first five or six segments bent sheghtly downwards near the tips and with
articulating facets, in the later segments nearly horizontal and not facetted ; in the
anterior segments bluntly poimted, in the later seements produced into short
spines, the spine on the tenth segment beimg apparently the longest; all the
pleure grooved, the groove being rather broad and, except near the extremities,
lying in the middle of the pleura.
Tail small, triangular. Axis broad, consisting of five segments, reaching
nearly, if not quite, to the posterior margin; bluntly conical. Lateral lobes
narrower than the axis, with (on each side) three distinct broad grooves, and a
fourth indistinct, all the grooves nearly at right angles to the axis, the ribs
between the grooves marked by a fine intermediate line. Margin narrow, without
spines.
Dimensions. —Full-grown specimens commonly attain a length of 20—25 mm.
OLENUS TRUNCATUS. 53
The British specimens of Olenus truncatus with which I am acquainted are
invariably very badly preserved and have often been mistaken for Olenus cataractes.
Belt, however, recognised the presence of the species in the Dolgelly district. From
O. cataractes it is easily distinguished by the shortness of the glabella, which is only
about half as long as the head, while in O. cataractes it extends nearly to the anterior
margin. ‘The breadth of the cheeks, the distance of the eye from the glabella, and
the triangular tail with five segments to the axis also serve to distinguish O. truncatus
from O. cataractes.
In the very imperfect state in which the specimens are usually found in Britain
it is not always easy to separate O. truncatus from O. gibbosus. The head of Olenus
truncatus is broader in proportion to its length and is straight or even emarginate
in front, while in QO. gibbosus the outline is nearly a segment of a circle. The genal
spines of O. truncatus are directed somewhat outwards, while in O. gibbosus they
run directly backwards. The axis of the thorax is narrower in O. gibbosus, and
there are fifteen instead of thirteen thoracic segments. In Olenus truncatus the
axis of the tail is broad and consists of five segments, and the lateral lobes are
narrow ; in O. gibbosus the axis 1s narrow and consists of at least seven segments,
while the lateral lobes are comparatively broad. The margin of the tail is entire
in Olenus truncatus, while in O. gibbosus it bears a small spine on each side, but it
is not often that the spine is sufficiently well preserved to be distinct.
Olenus micrurus is easily distinguished by its long glabella and small quadrate
tail; O. longispinus by its long backwardly-directed genal spines and its broad and
short tail, which has a circular rather than triangular outline.
Synonymy.—The earher writers do not distinguish between the Tvrilobus
truncatus of Brimnich and the Hntomostracites gibbosus of Wahlenberg, and
Briinnich’s own account would apply equally well to either species. He gives the
number of segments as twenty, but probably he included the rings of the tail, and
it may be remarked that he reckons twenty-four segments in his T'rilobus
[ Calymene]| tuberculatus. Wahlenberg identifies Briimnich’s species with his own
Hntomostracites paradowissimus, which 1s a Paradowides. Dalman and Burmeister
give T'rilobus truncatus and Hntomostracites gibbosus as synonyms.
Angelin appears to have been the first to recognise the differences, and his
definition of the two species has been accepted by most subsequent authors.
The form Trilobites gibbosus var. of Boeck and Olenus gibbosus var. of Kjerulf is
not sufficiently described by those authors to be identified, and it is on the
authority of Brégger that I have meluded it in the synonymy. The species
figured by Brégger himself and referred by him with some doubt to Olenus
truncatus shows six distinct segments in the axis of the tail.
Horizon and Localities—Lower Lingula Flags: Dolgelly; Cae Gwernog,
Mawddach Valley.
DA BRITISH CAMBRIAN TRILOBITES.
2. Olenus gibbosus (Wahlenberg). Plate V, figs. 8—10.
1821. Entomostracites gibbosus, Wahlenberg, Petrif. Tell. Suec., p. 39, pl. i, fig. 4.
1822. Paradoxides gibbosus, Brongniart, Crust. Foss., p. 35, pl. ii, fig. 6.
1827. Olenus gibbosus, Dalman, Om Palead., K. Vet. Akad. Hand]. (1826), p. 256.
1837. Olenus gibbosus, Hisinger, Leth. Suec., p. 19, pl. iv, fig. 3.
1854. Olenus gibbosus, Angelin, Pal. Scand., p. 44, pl. xxv, fig. 5.
1867. Olenus gibbosus, Belt, Geol. Mag., vol. iv, p. 295, pl. xii, fig. 5 a, b.
Head rather more than twice as broad as it is long, the outline forming a
seement of a circle. Glabella prominent, raised above the level of the cheeks,
narrower than the cheeks, short, separated from the front margin by a space
about equal to half its own Jength, narrowing slightly towards the front, truncate,
with three pairs of oblique glabellar furrows, of which the first pair is very
indistinct, occipital furrow well defined. Eyes moderate, crescentic, placed nearly
in the middle of the cheeks, distant from the glabella more than half the width of
the latter, connected with the anterior angles of the glabella by straight ocular
ridges which run nearly at right angles to the axis. Facial suture running
backwards and shghtly outwards from the anterior margin to the eye and thence
more strongly outwards to the posterior margin, which it cuts some distance
within the genal angle. The cheeks and frontal limb slope steeply downwards in
front of the glabella, less steeply towards the sides; fixed cheeks rather wide ;
free cheeks with faint vascular markings which radiate from the eyes. Margin
narrow, upturned in front. Genal angles produced into spines which are directed
backwards.
Thorax of fifteen segments, narrowing backwards from the sixth or seventh
seoment. Axis narrower than the pleure. Pleure straight and nearly hori-
zontal, the anterior segments facetted; anterior segments pointed, the later
seements produced into spines; all the pleurz grooved, the grooves being slightly
oblique.
Tail triangular. Axis narrow, rather less than the width of the lateral lobes in
front, almost cylindrical, with either six or seven distinct rings besides the
terminal portion, reaching to the posterior margin. Lateral lobes flat, with about
four shallow and rather indistinct furrows, the ribs between being interlined.
No definite marginal rim; a minute lateral spine on each side opposite the third
axial ring.
Dimensions —TVhe British specimens are very variable in size, but sometimes
attain a length of 35 mm. or more.
The presence of this species in the Lingula Flags of the Dolgelly district was
recognised by IT’. Belt. Many of the specimens are complete, but the state of
OLENUS MICRURUS. a)
preservation is poor. It is, however, readily distinguished from all the other
British species of the genus except O. truncatus and O. longispinus by the shortness
of its glabella. From O. truncatus it is distinguished by the rounded outline of the
head, the backwardly-directed genal spines, the narrow axis of the tail and thorax,
and the larger number of rings on the axis of the tail. The thorax consists of
fifteen segments instead of thirteen as in that species, and the tail bears minute
lateral spines. Owing to the state of preservation, however, it is seldom possible
to make use of the last two characters.
From 0. longispinus it is distinguished by the course of the facial suture in front
of the eye, the number of segments in the thorax and the tail, and the outline of
the tail, which, in O. longispinus, is circular rather than triangular.
Horizon and Locality —Lower Lingula Flags: Tyn-y-groes, Dolgelly.
3. Olenus micrurus, Salter. Plate V, figs. 11, 12.
1849. Olenus micrurus, Salter, Mem. Geol. Surv., Brit. Org. Remains, dec. i, pt. ix, p. 1, pl ix,
figs. 1, 2 (fig. 3 doubtful).
1866. Olenus micrurus, Salter, Geology of North Wales, Mem. Geol. Surv., vol. ui, p. 300, pl. u,
fig. 5 (fig. 6 doubtful).
=
General form depressed, narrowing somewhat rapidly towards the tail.
Head semi-circular. Glabella forming about one third the width of the head,
reaching forwards nearly to the anterior margin; almost oblong in shape, but
narrowing very shehtly and somewhat rounded in front, with a well-marked
neck-furrow and two (or possibly three) pairs of oblique glabellar furrows. Hyes
moderate, set a little in front of the middle of the cheeks and distant from the
elabella Jess than half the width of the latter, united with the anterior extremity
of the glabella by an oblique ocular ridge (which is very imperfectly shown in the
type specimen). Facial suture running from the anterior margin backwards to the
eye, and thence backwards and outwards to the posterior margin, which it cuts some
distance within the genal angle. Margin narrow, even in width. Genal spines
short, directed somewhat outwards as well as backwards.
Thorax of fourteen segments, increasing shghtly im width to the sixth or
seventh seement, and thence decreasing rapidly, the last two segments being very
narrow. Axis forming nearly one third of the total width in the anterior segments,
more than one third in the posterior segments. Pleure straight and horizontal,
obliquely grooved, the anterior pleure shghtly facetted; all, except perhaps the
first two, produced into backwardly-directed spines, which appear to attain their
ereatest length about the seventh segment.
Tail very small, subquadrate, shghtly emarginate behind the axis. Axis
cylindrical, wider than the lateral lobes, reaching to the posterior margin, showing
only one ring marked off from the rest. Lateral lobes flat, with a faint furrow
56 BRITISH CAMBRIAN TRILOBITES.
near the anterior border. Margin forming a raised rim, produced into a very short
spine on each side at the anterior angle.
Dimensions.—The length of the type-specimen shown in Plate V, fig. 12 must
have been about 35 mm.
The length of the glabella, which reaches nearly to the anterior margin,
distinguishes Olenus micrurus from all the other British species of the genus
excepting O. cataractes and O. mundus, and from these forms it 1s separated chiefly
by the characters of the thorax and the tail. In O. cataractes and O. mundus the
general shape is ovate, while in O. micrurus the body tapers rapidly from the
sixth or seventh thoracic segment, and the pleurz of the last two segments are
very short. The tail of O. micrurus is quite characteristic, with only one ring
differentiated upon the axis, and with the lateral lobes narrow and showing only
one faint furrow near to the anterior border.
The presence of the small spine at the anterior angles of the tail is not noted by
Salter, but it is distinctly visible in the specimen figured on Plate V, fig. 12, which
was one of his types. It is, however, by no means conspicuous, and can only be
seen when the specimen is lighted in a particular direction.
Olenus nicrurus is commonly quoted as a characteristic species of the Lingula
Flags, but so far as I am aware the only specimens in our museums which can be
referred with certainty to this species, are the two from near Trawsfynydd which
are shown in Plate V and upon which Salter’s figure appears to have been based.
The specimens from the Cwm-y-Swm Mine and from Marchllyn Mawr, to which he
refers, are much too imperfect for specific determination.
Horizon and Locality.—Lower Lingula Flags: Trawsfynydd.
4. Olenus cataractes, Salter. Plate V, figs. 13—17; Plate VI, fig. 1.
1864. Olenus cataractes, Salter, Mem. Geol. Surv., Brit. Org. Rem., dec. xi, pt. viii, p. 1, pl. viii, figs.
14, 14a, b.
1866. Olenus cataractes, Salter, Geology of North Wales, Mem. Geol. Surv., vol. iii, p. 300, pl. v, figs.
23, 23 a, 0.
1878. Olenus caractaci, Salter MS., Cat. Cainb. and Sil. Foss. Mus. Pract. Geol., p. 10.
Head semi-circular, marginate, produced into spines at the genal angles.
Glabella about one third the width of the head, reaching nearly to the anterior
margin, nearly parallel-sided but narrowing very slightly forwards, rounded in
tront, with a well-defined neck-furrow and three pairs of oblique glabellar furrows,
of which the first is very faint. Cheeks wide, free cheeks sometimes with faint
vascular markings radiating from the eye. Eyes small, crescentic, placed a little
in front of the middle of the cheeks, and distant from the glabella about half the
OLENUS CATARACTES. 57
width of the latter, united with the anterior end of the glabella by a very faint
ocular ridge. Facial suture running from the anterior margin backwards to the
eye, and thence backwards and outwards to the posterior margin, which it cuts
some distance within the genal angle. Margin narrow, even in width; genal
angles produced into spines which are directed backwards and are about as long as
the head.
Thorax of fourteen or fifteen segments, decreasing in width from the sixth or
seventh segment backwards. Axis about equal in width to the pleura. Pleura
nearly straight and horizontal, obhquely grooved; the fulcrum of the first segment
placed about half way between the axis and the extremity of the pleura, in the
following segments successively further out until in the seventh or eighth segment
it has disappeared ; outside the fulcrum the pleurz are shghtly bent downwards
and facetted, and end in short pots; beyond the seventh segment there is no
facet and the extremities are produced into spines directed backwards, the spime
of the tenth segment being the longest.
Tail small, sub-triangular. Axis forming about one third of the whole width,
conical, terminating bluntly a little in front of the margin, composed of four
seoments (including the terminal portion). Lateral lobes flat, with three broad,
shallow, outwardly-directed grooves, of which only the first is well defined; the
ridge between the first two grooves marked by a narrow impressed line. Margin
narrow, even, bearing on each side near the anterior angles a short, sharp,
backwardly-directed spine.
Dimensions.—Very variable, length from 10—40 mm.
From Olenus truncatus, O. gibbosus, and O. longispinus this form is readily
distinguished by the length of the glabella, which reaches forwards nearly to the
anterior margin, and this character is easily recognised even in very imperfect
specimens. Olenus micrurus presents a closer resemblance, and is distinguished
chiefly by the rapid narrowing of the hinder part of the thorax, the smallness of
the tail, and the presence of only one distinctly differentiated ring upon the
pygidial axis.
It often happens that in distorted specimens Olenus cataractes presents a
striking general resemblance to Parabolina spinulosa, and this is especially the
case when the specimen is laterally compressed. The thoracic segments then
appear to terminate in long spines, and even the tail may seem to bear several
spines, while the characters of the head are not strikingly different. It will be
observed, however, that the eye is placed considerably further back than in
Parabolina spinulosa, and the thorax is not provided with a row of tubercles upon
the axis. These characters will usually serve to distinguish between the two
forms in all but the most fragmentary specimens.
But the form with which O. catavactes is most nearly allied is O. mundus,
9
58 BRITISH CAMBRIAN TRILOBITES.
which is found along with it at Trefgarn Bridge. So close, indeed, is the
resemblance that the latter may ultimately prove to be only a young stage of
O. cataractes. There are, however, certain differences which appear to be
constant, and I have not yet discovered any intermediate forms. In O. mundus
the ocular ridge is much more strongly marked, the pleural spines are shorter,
the axis of the thorax bears a median tubercle upon each segment, and the axis
of the tail has only two or possibly three rings differentiated upon it instead of
four. Owing, however, to the small size of the specimens and the increasing
vagueness of the segmentation towards the end of the axis, but little importance
can be attached to the last character. O. cataractes is usually considerably larger
than O. mundus, but occasional specimens approach the latter in size.
Salter’s figure of Olenus cataractes is evidently a restoration, but he states that
the specimen is from Treflys and is in the Museum of Practical Geology, and
hence it would appear that the specimen upon which the restoration is chiefly
based must be that which is shown in Plate V, fig. 18. He lays some stress upon
the fact that the second and third pairs of glabellar furrows are continuous across,
but this is a pecuharity which is often met with in other species of the genus and
which appears to depend upon the mode of preservation—being due, in fact,
merely to the crumpling of the test between two points of weakness. The really
continuous glabellar furrows in such forms as Spherophthalmus alatus present a
very different appearance.
Owing to the imperfection of his material, Salter failed to observe the lateral
spines of the tail, but they are very clearly shown in the beautiful specimens
collected by Mr. Turnbull at Trefgarn Bridge, and they are distinctly visible in
some of those from the Maentwrog Falls, although, owing to the compression and
distortion of the specimens, they are lable to be overlooked.
Horizon and Localities—Lower Lingula Flags: Caen-y-coed, Maentwrog
Valley; Treflys, Criccieth; Portmadoc; Tal-y-sarnau; Trefgarn Bridge, Haver-
fordwest.
5.
5. Olenus mundus, sp. nov. Plate VI, figs. 2
General form depressed, ovate.
Head semi-circular, marginate, produced at the genal angles into short spines.
Glabella not quite so wide as the cheeks, narrowing very slightly forwards,
truncate in front, reaching nearly to the anterior margin, from which it is
separated by a space rather wider than the margin itself; neck-furrow strong ;
three pairs of glabellar furrows, of which the second and third are strongly
marked and very oblique, while the first is fainter and less oblique. Cheeks
rather wide; free cheeks with faint vascular markings radiating from the eye.
OLENUS MUNDUS. 59
Hyes of moderate size, set a little in front of the middle of the cheeks and distant
from the glabella about half the width of the latter, united with the anterior end
of the glabella by a strong ocular ridge which reaches the glabella just in front of
the first glabellar furrow. Facial suture running from the anterior margin back-
wards and slightly outwards to the eye, and thence more decidedly outwards to the
posterior margin, which it cuts nearly opposite to the end of the first thoracic
pleura. Margin narrow, even in width; genal spines slender, short and sometimes
bent shghtly outwards.
Thorax of fourteen segments, considerably narrower than the head, the
decrease in width regular and gradual. Axis rather wider than the pleure, bear-
ing a row of median tubercles (which are rather indistinct). Pleurze straight, the
fulcrum of the first segment placed about half way out, in the later segments
distant from the axis about two thirds the length of the pleure; pleure bent
shghtly downwards beyond the fulcrum, especially in the anterior segments, which
are facetted. The points of the first segments very short and directed outwards,
those of the later segments progressively longer and more and more backward in
direction, but all are short.
Tail small, short, rounded or subtriangular. Axis conical, blunt, forming
about one third the width, reaching to the posterior margin, consisting of three or
four segments. Lateral lobes very shghtly arched, marked by two fairly strong
furrows with a fine intermediate line. Margin sometimes shghtly expanded at
the anterior angles, as if it bore a small spine.
Diinensions—Leneth 6 or 7 mm.
The only species with which this form is likely to be confounded is Olenus
cataractes, and from this it 1s distinguished by its small size, the prominence of
the ocular ridges, the shortness of the pleural spines and the presence of tubercles
on the axis of the thorax. All these, except the last, are characters which might
reasonably be expected to disappear with age, and it 1s quite possible, therefore,
that O. mundus is the young of O. cataractes. It is the absence of intermediate
forms and the presence of the axial tubercles in the smaller form which prevent
me from accepting this view without further evidence.
Olenus mundus was found by Mr. V. M. Turnbull at Trefgarn Bridge,
Haverfordwest, along with Olenus cataractes and several minute and immature
forms, which may be the young of either species. | The material in which they le
is scarcely fine enough to preserve the details of these larval forms, and the
margins of the heads and tails and the extremities of the pleure are usually
lost or buried in the matrix. The most nearly perfect of the specimens is shown
in Plate VI, fig. 4, and in this the glabella extends forwards to the anterior margin
and is completely divided by transverse furrows into five segments, of which the
last appears to represent the occipital rng. The ocular ridge springs from the
60 BRITISH CAMBRIAN TRILOBITES.
first segment and runs close to the exterior margin, reaching nearly half way to
the genal angle. The thorax seems to consist of six segments and the tail of three,
but the division between the two regions is indistinct. The other specimen figured
is not so nearly perfect, but shows the margin of the head more clearly.
The presence of these young forms is, perhaps, an additional argument in
favour of the view that Olenus mundus is merely a stage in the development of
Olenus cataractes.
Horizon and Locality.—Lower Lingula Flags: Trefearn Bridge, Haverfordwest.
6. Olenus longispinus (Belt). Plate VI, figs. 6, 7.
1868. Conocoryphe ? longispina, Belt, Geol. Mag., vol. v, p. 9, pl. i, figs. 12—14.
Head nearly semi-circular, with the genal angles produced into long, slender,
backwardly-directed spines. Glabella very short, nearly as broad as long, about
two thirds the length of the head, and rather less than one third the width, nearly
parallel-sided, trancate in front, with two pairs of oblique glabellar furrows.
Hyes placed in the middle of the cheeks, distant from the glabella rather more
than half the width of the latter, united with the anterior angles of the glabella
by strong curved ocular ridges which run nearly at right angles to the axis.
Facial suture running inwards and backwards from the anterior margin to the
eye, and thence outwards and backwards to the posterior margin, which it cuts
nearly opposite to the end of the first thoracic pleura. Cheeks moderately convex.
Margin narrow; genal angles produced into long, slender, backwardly-directed
spines, which reach nearly as far as the end of the tail.
Thorax of fourteen segments, widening shghtly to the sixth segment, and
thence narrowing rather rapidly backwards. Axis about equal in width to the
pleurze in the anterior segments, narrower in proportion in the posterior segments,
each axial ring with its lateral extremities tuberculate and also bearing a small
median tubercle, which, however, is not always very distinct. Pleure straight,
obliquely grooved, the anterior pleure distinctly bent down at the fulerum and
produced into short outwardly-directed points; the extremities of the later
segments unknown.
Tail broad and short, rounded in outline. Axis narrower than the lateral
lobes, reaching to the posterior margin, consisting of three or four rings. Lateral
lobes flat, with three furrows. Margin entire.
Dimensions.—Length about 18 mm.
No other British species possesses the very long genal spines characteristic of
this species. Olenus truncatus and O. gibbosus, both of which have short glabellas,
PARABOLINA. 61
are the species which approach it most nearly in the characters of the head, but
in O. longispinus the glabella is proportionally even shorter and considerably wider
than in those forms, the sides are more nearly parallel, and it is more sharply
truncate in front; the eyes are placed further back and nearer to the glabella, and
the anterior branch of the facial suture runs inwards to the eye. In all the other
British species the glabella reaches nearly to the anterior margin.
The thorax differs from that of the other British species excepting O. mundus
in bearing a median tubercle upon each axial ring.
In the shortness and breadth of the tail the species is unlike any of the true
Oleni.
As has already been observed by Mr. F. R. C. Reed,’ Olenus longispinus presents
several of the features characteristic of Parabolinella, and very possibly it should
be referred to that genus. It is in the characters of the tail and the inward course
of the anterior branch of the facial suture that the chief resemblance les, but it
differs from the typical species of Parabolinella in the extreme shortness of the
elabella, the backward position of the eyes, and perhaps in the number of thoracic
segments. It appears to be an intermediate form, but for the present I prefer to
put it in Olenus rather than mm Parabolinella.
Horizon and Locality.—Upper Lingula Flags: Dolgelly ; Moel Gron; Penmorfa.
Genus PARABOLINA, Salter.
The genus Parabolina is closety allied to Olenus, but is distinguished by the
following characters: The glabella is long, more or less truncate in front, and
separated from the anterior margin by a very narrow frontal limb; the eyes are
placed far forwards and very near to the anterior angles of the glabella ; the thorax
consists of twelve segments; the pleurze are obliquely grooved and terminate in
spines ; the tail bears several spines upon each side.
The name was originally proposed by Salter in 1849” for a section of the genus
Olenus (sensu luto), characterised by possessing twelve thoracic segments and
a spinose tail. Angelin elevated this section to the rank of a distinct genus. It is
undoubtedly a very clearly-defined group, and, as Olenus, in the wider sense,
includes too great a variety of forms to admit of precise definition, I propose to
follow Angelin’s example.
1 Geol. Mag. [4], vol. vii (1900), p. 254.
* Mem. Geol. Surv., Brit. Org. Rem., dec. ii, pt. ix, p. 2.
62 BRITISH CAMBRIAN TRILOBITES.
1. Parabolina spinulosa (Wahlenberg). Plate VI, figs. 8—11.
1821. Entomostracites spinulosus, Wahlenberg, Petrif. Tell. Suec., p. 38, pl. 1, fig. 3.
1822. Paradowides spinulosus, Brongniart, Crust. Foss., p. 32, pl. iv, figs. 2, 3.
1827. Olenus spinulosus, Dalman, Om Palead., p. 256, pl. vi, fig. 4.
1837. Olenus spinulosus, Hisinger, Leth. Suec., p. 19, pl. iv, fig. 2.
1838. Trilobites gibbosus, var. (pars), Boeck, Keilhau’s Gea norv., p. 143 (teste Brogger).
1843. Paradoxides spinulosus, Burmeister, Organ. d. Trilob., p. 80.
1854. Parabolina spinulosa, Angelin, Pal. Scand., p. 46, pl. xxv, fig. 9.
1857. Olenus spinulosus, Kjerulf, Geol. d. siidl. Norw., p. 284 (teste Brogger).
1864. Olenus (Parabolina) spinulosus, Salter, Mem. Geol. Surv., Brit. Org. Rem., dec. xi, pt. viii,
pl. vii, fig. 16.
1864. Olenus (Parabolina) serratus, Salter, ibid., p. 4, pl. viii, fig. 5.
1865. Parabolina spinulosa, Kjerulf, Veiviser ved geol. excursioner i Christiania omegn, p. 2.
1866. Olenus (Parabolina) serratus, Salter, Geol. of North Wales, Mem. Geol. Surv., vol. iii, p. 301,
ple, figs./6,"7.
1873. Olenus (Parabolina) spinulosus, Salter, Cat. Camb. and Sil. Foss. Mus. Cambridge, p. L.
1882. Parabolina spinulosa, Brogger, Die Silur. Etagen 2 und 38, p. 100, pl. i, figs. 12 a—e.
1904. Parabolina spinulosa, Persson, Geol. Foren. Stockholm Forh., vol. xxvi, pl. ix, fig. 24.
Head forming approximately a segment of a circle but with the anterior
margin nearly straight. Glabella rather less than one third the width of the
head, almost rectangular but narrowing slightly towards the front and with the
anterior angles rounded, reaching forwards nearly to the margin. Three pairs of
oblique glabellar furrows, of which the first is shorter, less oblique and less
strongly marked than the others; occipital furrow well defined especially at the
sides, the occipital rig divided by two oblique furrows into a central portion
which bears a median tubercle, and two anterior lateral portions. Eyes of
moderate size, placed far forwards and very close to the anterior angles of the
glabella, with which they are connected by strongly marked ocular ridges. Facial
suture running directly backwards from the anterior margin to the eye, and thence
outwards and backwards to the posterior margin, which it cuts nearly opposite to
the extremity of the first thoracic pleura and some distance within the genal
angle. Frontal limb very narrow; fixed cheeks very narrow in front of the eye,
widening rapidly backwards, with a strong neck-furrow ; free cheeks ornamented
with branching and anastomosing ridges, which radiate from the eye; the posterior
margin not in line with that of the fixed cheeks but turning slightly forwards.
Head surrounded by a narrow marginal rim and furrow; genal angles produced
into long, slender, backwardly-directed spines.
Thorax of twelve segments. Axis forming about one third of the whole width,
ach segment provided with a median tubercle. Pleure shghtly bent downwards
towards their outer extremities, produced into spines, which in the first few
segments are rather short, but from the fifth or sixth segment onward are of
considerable length ; the spines of the first segment directed somewhat outwards,
PARABOLINELLA. 63
those of the later segments progressively more and more directly backwards; all
the pleurz deeply grooved by oblique furrows which are continued into the spines.
Tail somewhat triangular, without any raised margin. Axis broad, conical,
reaching to the posterior margin, formed of four segments (including the terminal
portion), of which all but the last bear a median tubercle. Lateral lobes flat,
composed, apparently, of three pleure similar to the posterior thoracic pleure,
and each produced into a long backwardly-directed spine, the first pleura nearly
at right angles to the axis, the others oblique. Besides the three spines on each
side there is a pair of spines immediately behind the axis.
Dimensions.—Very variable; length from 8 to 30 mm., commonly about 25 mm.
The form with which Parabolina spinulosa is most likely to be confounded is
Olenus cataractes. In perfect specimens the differences are sufficiently obvious ;
but, as has already been remarked in the account of O. cataractes, compressed
specimens of that species often appear to bear long thoracic and pygidial spines.
They may, however, be distinguished by the more backward position of the eyes
and the absence of axial tubercles ; and a close examination will usually show that
the appearance of long spines is due to wrinklings on the surface of the slate in
which the specimen les.
Some of the British specimens of Parabolina are very small, and in some the
spines of the tail and thorax seem to be very short, so that at first sight they
appear to differ from P. spinulosa. I have, however, been unable to recognise any
of the other species described by Moberg’; and the shortness of the spines seems
to be due in some cases to the youth of the individual and in others to the fact that
the extremities are imperfectly preserved. The specimen from Mr. G. J.
Williams’s collection shown in Plate VI, fig. 11, is one of the most distinct of these
forms ; but other specimens, which Mr. Williams has kindly lent me, and which came
from the same locality, seem to indicate that there are stages intermediate between
this and the normal Parabolina spinulosa. For the present, therefore, I look upon
these small and short-spined forms as stages in the development of that species.
Horizon and Localities—Upper Lingula Flags: Rhiwfelyn, Craig-y-Dinas,
Mawddach Valley; Nant-y-derbyniad; Nant Cistfaen, Llyn Tryweryn; Bryn
Cyfergyd, Cwm Cynfal; Carreg Wen, Borth; Penmorfa; Penmaenpool; Gwern-
y-barcud, Dolgelly.
Genus PARABOLINELLA, Brégger.
The genus Parabolinella resembles Parabolina in some respects, but possesses
an entire instead of a spinose tail. There are also other important differences,
and the genus appears to be connected (through Olenus longispinus) with Olenus
proper rather than with Parabolina.
' Geol. Foren. Stockholm Firh., vol. xx, pp. 259—277.
64 BRITISH CAMBRIAN TRILOBITES.
The glabella is rectangular, sometimes narrowing slightly towards the front,
shorter than in Parabolina, with two or three pairs of glabellar furrows, of which
the last two pairs are very oblique; the frontal limb between the glabella and
the anterior margin is fairly wide. ‘he eyes are placed about half way between the
anterior and posterior margins and very close to the glabella, with the anterior
angles of which they are connected by oblique ocular ridges. The facial suture runs
inwards and backwards from the anterior margin to the eye and thence outwards
and backwards to the posterior margin. ‘The number of thoracic segments varies,
but in the adult (in all the species in which the number is known) it is never less
than fourteen. The tail is broad, rounded in outline, marginate, and without
spines.
1. Parabolinella williamsoni (Belt). Plate VI, fig. 12.
1868. Conocoryphe ? williamsonii, Belt, Geol. Mag., vol. v, p. 9, pl. ii, figs. 7—11.
1873. Olenus plantii, Salter, Cat. Camb. Sil. Foss. Mus. Cambridge, p. 11.
1900. Olenus (Parabolinella) planti, F. R. C. Reed, Geol. Mag. [4], vol. vii, p. 303, pl. xu,
roe Ih
Head semi-circular. Glabella nearly rectangular, narrowing shghtly towards
the front and with the anterior angles somewhat rounded, separated from the
marginal rim by a broad frontal limb; two pairs of glabellar furrows, both very
oblique and both obsolete near the axial furrows, the last pair meeting in the
middle of the glabella, the first pair nearly meeting; neck-segment defined by a
furrow, which becomes weak towards the middle and obsolete near the axial
furrows, obscurely divided into three portions by oblique furrows, which pass
from the posterior lateral angles of the segment nearly to the middle of the
occipital furrow ; the central portion thus defined bears a very indistinct median
tubercle. Eyes placed about half way between the anterior and posterior margins,
very near to the glabella, with the angles of which they are connected by oblique
ocular ridges. Facial suture running from the anterior margin backwards and
inwards to the eye and thence backwards and outwards to the posterior margin,
which it cuts at a distance from the axial furrow less than the width of the
glabella. Margin formed by a narrow raised rim.
Thorax probably of fifteen segments. Axis as wide as the pleure in the
anterior part of the thorax, but in the posterior part not much more than half the
width of the pleurz, some of the rings showing very obscure indications of median
tubercles. Pleure straight, obliquely grooved, shghtly bent down at the fulcrum,
which in the anterior pleurz is placed very near the axis, in the posterior pleure
far out ; the anterior pleuree distinctly facetted and terminating in points directed
PATE Vi
FIGS PAGE.
Olenus truncatus (Brinnich). 52
1-3. Swedish specimens. 1, nearly complete; 2, head; 3, free cheek. Olenus schists,
Andrarum, Scania. Collected by Dr. J. E. Marr. Sedgwick Museum.
4—6. Some of Belt’s specimens. Upper Maentwrog Beds, Dolgelly. British Museum, 17558
(fig. 4), 1.7561 (fig. 5), 17556 (fig. 6). (Belt Collection.)
7. Tail. Lower Lingula Flags, Cae Gwernog, Mawddach Valley. Sedgwick Museum.
Olenus gibbosus (Wahlenberg). 54
8. Nearly complete specimen, showing the lateral spine on the margin of the tail. Lower
Maentwrog Beds, Dolgelly. British Museum, I 7546. (Belt Colfection.)
9. Head and part of thorax. Lower Maentwrog Beds, Dolgelly. British Museum, 17548.
(Belt Collection.)
10. Head. Lower Maentwrog Beds, Dolgelly. British Museum, I 7538. (Belt Collection.)
Olenus micrurus, Salter. 55
11, 12. Salter’s types. Lower Lingula Flags, Trawsfynydd. Museum of Practical Geology,
8948. (Both specimens are on the same slab of rock, and both are in the form of
external moulds. The figures are drawn from artificial casts of these moulds.)
Olenus cataractes, Salter. 56
13. Probably Salter’s type. Lower Lingula Flags, Treflys, Criccieth. Museum of Practical
Geology, 8946.
14. Complete but distorted specimen. Lower Lingula Flags, Caen-y-coed Quarry, Maentwrog.
Sedgewick Museum. (The counterpart of this specimen is in the Museum of Practical
Geology, 8879.)
15. Specimen distorted by cleavage, apparently with long thoracic and pygidial spines. This
appearance is due to wrinkling of the surface of the slate. Lower Lingula Flags,
Caen-y-coed Quarry, Maentwrog. Sedgwick Museum.
16. Thorax and tail. Lower Lingula Flags, Trefgarn Bridge, Haverfordwest. Collected by
Mr. V. M. Turnbull. Museum of Practical Geology, 22715.
17. Specimen showing fourteen thoracic segments. Lower Lingula Flags, Trefearn Bridge,
Haverfordwest. Collected by Mr. V. M. Turnbull. Museum of Practical Geology,
22717.
All the figures on this plate are drawn natural size,
1ISO08
PALZ ONTOGRAPHICAL SOCIETY,
Lake, Camerian Irilobites.
a
Olenu
™ aTty
PLAT He Vil.
FIGS. PAGE.
Olenus cataractes, Salter. 56
1. Specimen showing the points of the thoracic pleure. The last thoracic segment appears
to be fused with the tail, which accordingly bears two spines on the left-hand margin,
instead of one. Lower Lingula Flags, Trefgarn Bridge, Haverfordwest. Collected by
Mr. V. M. Turnbull. Sedgwick Museum. Nat. size.
Olenus mundus, sp. nov. 58
2,5. Forms supposed to be adult. Lower Lingula Flags, Trefearn Bridge, Haverfordwest.
Collected by Mr. V. M. Turnbull. Sedgwick Museum, x 4
4,5. Young forms. Lower Lingula Flags, Trefgarn Bridge, Haverfordwest. Collected by
Mr. V. M. Turnbull. Sedgwick Museum. x 20.
Olenus longispinus (Belt). 60
6. Probably one of Belt’s types. Locality uncertain (labelled Conocoryphe bucephala, Upper
Ffestiniog Beds, Dolgelly; but the name and probably the horizon are incorrect).
British Museum, 17592. (Belt Collection.) x 1J.
7. A shellac cast of a specimen now unknown. Upper Dolgelly Beds, Dolgelly. British
Museum, 17577. (Belt Collection.) x 1.
Parabolina spinulosa (Wahlenberg). 62
8. A rather small specimen. Upper Lingula Flags, Rhiwfelyn. Mr. G. J. Williams’
Collection. (Drawn from an artificial cast of the specimen, which is an external
moulds),
Llyn Tryweryn. Mr. G. J. Williams’ Collection, x 3.
Parabolinella williamsoni (Belt). 64
12. Cranidium, parts of thorax, and tail, probably in their natural relitive positions. Upper
Lingula Flags, Moel Gron. Sedgwick Museum. (Drawn from an artificial cast of the
specimen, which is a mould. The counterpart of the specimen is in the British Museum,
59291. Figured by Mr. F. R. C. Reed as Olenus [| Parabolinella| planti, Geol. Mag.,
1900, pl. xii, fig. 1.) Nat. size.
PALA ONTOGRAPHICAL SOCIETY, 1908
Lake Cambrian Trilobites. PLATE Vy]
x4 ae
R ell 7 7 al
qa . oes a
Brock, de] London Stereoscopic Co. im
Palxontographical Society, 1908.
A MONOGRAPH
BRITISH GRAPTOLETES.
BY
GERTRUDE L. ELLES, Sc.D.,
LATE GEOFFREY FELLOW, NEWNHAM COLLEGE, CAMBRIDGE ;
AND
ETHEL M. R. WOOD, D.Sc.
[Mrs. SHAKESPEAR],
OF NEWNHAM COLLEGE, CAMBRIDGE; AND THE UNIVERSITY OF BIRMINGHAM.
EDITED BY
CHARGES GAPWORTE tu 3); 2. i:8:,
PROFESSOR OF GEOLOGY IN THE UNIVERSITY OF BIRMINGHAM.
PARES VA.
PaGEs cxxi—exlviii, 273—358; Puares XXXII —XXXV.
LON DON:
PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.
1908.
PRINTED BY ADLARD AND SON, LONDON AND DORKING.
HISTORY OF RESEARCH. CXXl
another—whether the different individuals have been developed by budding from
the ccenosare, or whether they are developed from, and connected with the one
immediately preceding—must be considered to begin already in the sicula, even if
it has been convenient, for the sake of description, to distinguish one part as the
‘connecting canal.’ ”
The “ connecting canal,” as defined by Holm, is the canal which “ arises almost
simultaneously with the left theca and the common canal for the left half of the
polypary,’ and which “crosses the dorsal side of the sicula and gives rise to
the third theca and the common canal for the right half of the polypary.” (This
canal is not the same as that for which Tornquist used the term ‘“‘ connecting canal,”
and Térnquist has later proposed the name “ crossing canal” for Holm’s structure.)
The Virgula.—His observations lead him to the conclusion that “a virgula
corresponding to that in Diplograptus and Monograptus cannot occur in the
Dichograptide,” at any rate ‘embedded in the dorsal side of the branches.”
Even in those cases in which the “sicula is embedded in the polypary, a
virgula need not of necessity be present,’ and Holm fails to find any trace of one
in Phyllograptus.
He points out that the “cylindrical chitinous thread which originates as a
result of growth within the apertural end of the sicula” in Diplograptus, etc., as
described by Wiman, “stands evidently in no relation whatever to the real virgula,
but may be regarded as an apertural spine.” And he draws especial attention
to the fact that “the presence of a virgula has hitherto been considered as the
main character of Graptolites” (Rhabdophora), “although such was never
described or expressly mentioned except in the groups Diplograptide, Mono-
eraptidee, and Retiolitide.”
The structure of Didymograptus minutus, D. gracilis, and D. gibberulus is
described in detail.
The genus T'etragraptus, of the development of which little was known, is
shown by Holm to pass through the same early stage as a Didymograptus
(“ Didymograptus stage”). The four stipes arise by a “direct splitting of the
common canal by a vertical wall” on each side of the connecting canal. This
structure is worked out in specimens of 7’. Bigsby.
The development of the genus Phyllograptus is proved to be practically identical
with that of Tetragraptus, but the branches, instead of having “four independent
periderm walls, form a single, cruciform, four-winged, longitudinal septum.” The
sicula is embedded in the polypary, but no virgula has been detected.
This memoir is illustrated by excellent figures.
The second important paper, published in 1895, was by Wiman, and was
perhaps even more far-reaching in its results.
The author commences with an account of the methods adopted by him for
preparing the specimens examined.
CXXI BRITISH GRAPTOLITES.
1895. He next discusses certain controversial points with refer-
Wimen. ence to the work of Térnquist and Holm. He accepts the
“Ueber die Grapto- facts obtained by Tornquist, and considers that their diffe-
liten,” * Bull. Geol. — rences of opinion concern questions of terminology only.
Instit. Upsala,’
By the term “theca” he means “a part of the test of
art. no. 6.
a bilaterally symmetrical animal,” and he repeats that ‘“ the
individuals corresponding to the thecze were developed from other similar indi-
viduals, and not from a substance contained in any common canal.” “ This,” he
writes, “is not only clear from the course of the growth-lines,” but receives
additional support from the recent discoveries made by himself as to the structure
of the Dendroidea, in which there is no common canal.
He acknowledges the correctness of Térnquist’s view that there is possibly
always a longitudinal septum in Diplograptus.
He agrees generally with Holm as to the structure of Didymograptus, but
considers it advisable to retain the word “sicula,” though he regards it as
probably the first theca, and he accepts Holm’s view that the apical part of the
sicula is the initial part and the youngest.
Wiman then gives a classification of the Graptolitidz in general. This agrees
in essentials with that proposed by Lapworth (1873), but is modified in some
particulars.
The family of the Monograptide is first described, and the typical structure of
a Monograptus is exemplified in Monog. dubius, M. lobifer, and M. discus.
He places the genus Azygograptus in the family of the Monograptide on
account of its having only one row of cells, but he considers it to be a Didymo-
graptus-like form in which one branch is missing and that it probably belongs
to the Dichograptidee, with which it is also contemporaneous.
Dimorphograptus raay be considered as a transition form between the Diplo-
graptide and the Monograptidee.
The Dichograptide he divides into two sub-groups according as they resemble
Didymograptus or Tetragraptus.
He points out that in Didymograptus the opening between the sicula and
the first theca may not only occur on the initial or the apertural part, but may
occupy very different positions on the bilaterally symmetrical sicula.
In the Graptoloidea he believes there is no “essential difference”? between
monopodial and dichotomous branching, though in the Dendroidea it would have
more significance.
Wiman attaches considerable importance to Hopkinson’s discovery of partition
walls in Tetrag. serra between the common canal and the thece, and he indicates
the analogy between this structure and that in the Dendroidea. He suggests that
the “ Graptoloidea are only the most superficial periderm of the Dendroidea” :
“the proximal projections of the thecee in the Dendroidea, which fill the common
HISTORY OF RESEARCH. CXXill
canal with many delicate tubes,’ were “still thinner in the Graptoloidea and less
likely to be preserved, so that they have almost entirely disappeared, and have only
exceptionally left behind traces of their existence.”
The structure of the Diplograptide is next discussed, and Diplograptus
uplandicus, n.sp., and Climacograptus Kuckserianus, Holm, are taken as examples.
An interesting new form—Climacog. retioloides—is also described.
The family of the Phyllograptidee is retained by Wiman with full knowledge
of the demonstrations of Holm that its structure is essentially similar to that of
Tetragraptus.
The histology of the Graptolite periderm is next discussed, and Wiman
concludes that in Monograptus there are only three layers, a middle thick one and
a thin one on each side of it.
Retioloidea.—In the group of the Retioloidea Wiman gives a full description
of the structure of [etiolites nassa.
Dendroidea.—Vhe latter part of Wiman’s paper is of especial interest, containing
many new facts of far-reaching importance connected with the group of the
Dendroidea.
Wiman shows by means of sections that “in all Dendroidea there can be
distinguished three different kinds of individuals: nowrishing individuals (which
he also calls thecz, since they doubtless correspond to the thecz in the Grapto-
loidea), budding individuals, and sewual individuals or gonangia.”
The Dendroid structure is described in great detail in the case of several
species and genera of the Dendroidea. In all cases the budding individual never
opens to the exterior, but itself gives rise to three new individuals, and these, as
they grow, gradually fill up the whole of the cavity of the mother budding theca.
The species described include Dictyonema rarum, LD). peltatum, J). tuberosum,
and D. flabelliforme. Dendrograptus (?) elandicus, LD. (?) balticus, D. (?) bottnicus,
and Ptilograptus suecicus.
The method of branching in the Dendroidea is carefully worked out in
Dendrog. (?) elandicus.
In Ptilograptus swecicus the structure is somewhat different. ‘The branches
carry twigs” which spring out alternately to right and left, and “ these consist of
four individuals, opening one after the other.”
The mode of growth of these various forms of Dendroidea is very different,
some having a sicula, others having a disc from which a stem proceeds. In
Dictyonema peltatum “a large number of branches spread centrifugally within a
b]
dise,”’ and then rise up, “branch, anastomose, and join again by means of the
ordinary connecting fibres.” ‘* The proximal ends of the branches ” in this species
do not “ possess the intricate structure that characterises the distal parts,” and
resemble those in a Monograptus.
Wiman shows clearly from the foregoing that the older generic diagnoses of the
CXX1V BRITISH GRAPTOLITES.
Dendroidea, drawn up as they were when practically nothing was known of their
structure, are now of little value, but he admits that a new classification would
as yet be impracticable and inadvisable.
As respects the systematic position of the Graptolites he considers that it is
impossible to say more than that the ‘“ Graptolites are bilaterally symmetrical
Invertebrates.”
Phylogeny.—Wiman discusses the relationship between the Graptoloidea and
the Dendroidea, and considers that “they are two parallel stocks of equal value
in which the division of labour is performed in somewhat different ways.”
“In the Graptoloidea the different functions (while all the individuals of the
first order remain the same) are shared among different organs.” “In the
Dendroidea, on the other hand, the different functions are shared by three different
forms of individuals of the first order.”
The theory that the Graptoloidea are descended from the Dendroidea seems to
him very improbable; while the reverse idea, namely that the Dendroidea are
descended from the Graptoloidea, meets with greater favour, as it is usual for
“division of labour in a colony to bring about a difference of individuals.”
The mode of life of the Graptolites is next dealt with, and Wiman concludes
that the only possible view to take is that ‘‘ the Graptolites, in some way or other,
stood upright ” and lived in the “ deeper littoral regions.”
The paper concludes with an Appendix giving an abstract of Ruedemann’s
discoveries of colonies of Diplograptus attached by their virgulas, and some of the
points referred to there are discussed and criticised. Exception in particular is
taken to Ruedemann’s idea that these colonies were provided with a swimming
bladder.
Considerable light had already been thrown on the mode
of life and development of the Diplograptidze by Ruedemann’s
discovery of some remarkable specimens of forms referred by
1895.
Ruedemann,
“Synopsis of the Mode :
of Growth and Develop. him to Diplograptus pristis and Diplog. pristiniformis (after-
ment of the Graptolitic wards named Ruedemanu). The first notice of this was
genus Diplograptus,” given in an abstract published by him in the American
mee dou chee Journalior Seience.
ser. 3, vol xlix, no. 294. : : ; :
Ruedemann summarises his conclusions as follows:
(1) These two species grow in “ compound colonial stocks which appear in the
fossil state as stellate groups.”
(2) “The virgule are joined to a central connecting stem, the ‘funicle’ of
Hall, which is mostly extended to a vesicle of quadrangular shape.” The funicle
is “enclosed in a central disc” which is a “thick, chitinous capsule” also
quadrangular in shape.
(3) “The central dise is surrounded by a verticil of oval capsules,” in number
four to eight or more. Some of these oval appendages are seen to contain sicule
HISTORY OF RESEARCH. CXXV
“ which radiate from an axial club-shaped protuberance within the vesicle, to which
they are joined by the filiform prolongation of their pointed ends.” Ruedemann
compares these vesicles with the gonangia of recent Hydrozoa.
(4) Overlapping the gonangia and even the proximal ends of the stipes, there
is an organ which he compares with the air-bladder or pneumatocyst of the
Discoideze and which he regards as having acted as a float.
(5) The siculee “at the time of developing the first two hydrothecs, possess a
quadrangular plate, joined by a small node in the centre to the end of the filiform
proximal process’”’; while at a slightly later stage of development four oval
impressions can be seen around the central node. This quadrangular plate (or
probably vesicle) develops into the pneumatocyst, the central node into the funicle
and central disc, and the small oval impressions probably indicate the gonangia.
(6) From the position of the sicule at the remote end of the stipes the “ so-
called proximal sicula-bearing end of the single stipes appears in the compound
colonial stock as the distal one.” “The stipe grows backward towards the centre
and the sicula is carried to the distal end.”
(7) With regard to the affinities of the Graptolites, Ruedemann points out that
by the “ possession of a pneumatocyst and the arrangement of the reproductive
organs at the bases of the stipes, the colonial stocks of Diplograptus had a general
similarity to those of certain Siphonophora, while the chitinous structure of the
hydrothecz and gonangia can be only referred to the Sertularians.”
1895. Matthew described in 1895 some new species of Clono-
Matthew, G. F.., graptus, Bryograptus, etc., from the lower part of Division 3
“Two new Cambrian of the St. John Group. Clonograptus proximatus, sp. nov.,
Graptolites with Notes esembles Clonog. tenellus in many respects; unlike the latter
on other Species of : : mae : - re
Craptalidie of that it occurs in association with Dictyonema flabelliforme and not
Age,” ‘New York Acad. above it. Matthew distinguishes Clonograptus from Bryo-
Sci. Trans.,’ August — graptus by its bemg “devoid of the sicula, or with the sicule
29th. obscure, absorbed, or merged in the funicle.” Four species of
Bryograptus are described and figured: Bryog. patens, B. spinosus, BD. lentus, LD.
retroflexus? A fragment of Callograptus is figured and two specimens of
Dictyonema flabelliforme, showing “ short rootlets developed from the proximal end
of the sicula.” As regards the occurrence of the last-named form in America,
Matthew states that the species was not a ‘solitary Graptolite,” as in some parts
of Hurope, but was associated sparingly with Bryograptus and Clonograptus.
As to the phylogenetic relationships of the Graptolites he writes, ‘‘ the succes-
sion of the Dichograptide in the Cambrian and Lower Ordovician is a good
exemplification of increased condensation of structure due to selection; for the
many-branched forms of the former are gradually replaced by the V'etragraptt and
these by the Didymograpti of the Upper Arenig.” He repeats his former view
that the Bryograpti were the ancestors of Dictyonema.
CXXV1
1895.
Lake,
“The Denbighshire
Series of South
Denbighshire,” ‘ Quart.
Journ. Geol. Soc.,’
vol. li.
1895.
Perner,
‘Htudes sur les Grapto-
lites de Boheme,”’ pt.
ii; ‘ Monographie des
Graptolites de I’ Ktage
Ds
BRITISH GRAPTOLITES.
During the same year Lake noted the existence of both a
Wenlock and Lower Ludlow Graptolitic fauna in the Den-
bighshire series of 8. Denbighshire.
The second part of Perner’s work on the Bohemian
Graptolites, including the species found in Ktage D, was pub-
lished in 1895. Several new species are described and
figured, but owing to the poor state of preservation and
fragmentary condition in which these are found in Bohemia,
any certain identification of them is a matter of difficulty.
The following are described and figured :
Dichograptus (2?) leptotheca, n. sp.
Tetragraptus caduceus.
Didymograptus.—(Group A)—D. bifidus, D. Murchisoni, D. denticulatus, D.
oligotheca, D). indentus var. nanus, D. spinulosus, D.
D. Wapworthi, D. bifidus var. incertus, ). vacillanoides.
clavulus, /). Barrandei,
(Group B)—D. v-fractus.
(Group C)—D. pennatulus: D. linguatus, D. lonchotheca, D. pennatulus var.
hamatus, J). retroflexus.
Dicellograptus anceps.
Cryptograptus tricornis.
Climacograptus tectus.
Diplograptus pristis, D. euglyphus var. angustus, D. lobatus, J. lingulitheca,
D. terres, D. insculptus, D. rugosus var. Fritschi, D. truncatus, D. foliaceus var.
vulgatus.
Dendrograptus constrictus.
A table is given showing the range of each species.
A useful list of works published on the Graptolites in general and an historical
account of the Graptolites in Bohemia, are prefixed to this second part of Perner’s
work.
1895.
Nicholson and Marr,
“ Phylogeny of the
Graptolites,” ‘Geol.
Mag.,’ dee. 4, vol. ii.
that the next most important point as “‘indicatine genetic relationship,’
I g )
An important paper bearing on “The Phylogeny of the
’ was published by Nicholson and Marr in 1895.
The authors conclude (1) that ‘the character of the hydro-
thece is the most important point to retain in view in
Graptolites ’
separating different families of the Graptoloidea”’; and (2)
’
is the
angle of divergence of the stipes; while the number of stipes, on which the
present classification of the Graptolites largely depends, is relatively insignificant.
In consonance with these conclusions, the authors take the eight known species
of Tetragraptus, and group round each of them those species of Dichograptus,
HISTORY OF RESEARCH. CXxvil
Bryograptus and Didymograptus which agree with them most closely in the character
of the thece and the “angle of divergence.” Group 1 contains Bryograptus
Callavei, Tetrag. Hicksti, and Didymog. affinis; Group 3 Bryog. ramosus, Tetrag.
fruticosus and Didymog. Murchisoni; Group 6 Tetrag. Bigsby, Didymog. gibberulus,
and an unknown Dichograptus, and so on. In those cases where, in any corre-
sponding place in a given group, there 1s no species with the required characters to
fill the gap, the authors confidently assert that further research will probably
reveal its existence. The authors hold that the members of each of these groups
are phylogenetically related, and that it is very difficult to understand how the
“extraordinary resemblances between the various species of Tetragraptus and
Didymograptus have arisen, if, as usually supposed, all the species of these genera
have descended from a common ancestral form for each genus, in the one case
’
four-branched, in the other case two-branched;” ‘‘on the other hand, it is
comparatively easy to explain the more or less simultaneous existence of forms
possessing the same number of stipes, but otherwise only distantly related, if we
imagine them to be the result of the variation of a number of different ancestral
types along similar lines.” They suggest that the genus Monograptus also may
contain “‘ descendants of more than one family.”
The authors point out that if their conclusions are correct, the present nomen-
clature would have to be eventually altered. Meanwhile they propose to retain such
names as Monograptus, Didymograptus, etc., as “ generic’ names, but the “ species
placed under these different groups do not belong to definite genera” (in the strict
biological sense of the word): they constitute cases of what Buckman terms the
“hetero-genetic homceomorphy ” of forms which are only distantly allied to one
another.
They adduce briefly reasons for this “special case of mimicry, and endorse
Clement Reid’s suggestion that the variations in form may be connected with the
supply of food”; the necessity of providing food brought about a reduction in
the number of stipes, and also a change in the direction of these stipes. Those
series of hydrothecee which were farthest apart would have a better chance of
obtaining food, and thus the “angle of divergence” increased from a very small
angle until it reached its maximum of 360° in Phyllograptus, Diplograptus, ete.
Variations in the form of the hydrothecz may also be explained on the same ground.
In a note to this paper, Nicholson and Marr suggest the new specific name of
Tetragraptus inosculans for those forms which resemble Tetrag. Ligsbyi, but in
which the stipes are in contact or even more or less fused.
1895. ; : :
Hall T. S. Hall discussed at considerable length the question
“Notes on Didymo- Of the synonymy of Didymograptus caduceus in a paper
graptus caduceus, with published in 1895. He concludes that Salter’s name D.
remarks on its caduceus has priority over D, gibberulus, and therefore the
” «Proc. Roy.
eo) tae lather should talleont of use:
Soe. Victoria,’ vol. viii.
CXXViil BRITISH GRAPTOLITES.
1896. Ruedemann’s preliminary notice on the development of
Ruedemann, Diplograptus was followed about a year later by a more com-
“ Development and
Mode of Growth of
Diplograptus,” ‘N.Y. ; : =
State Geol. Annual modified as the result of a further investigation of additional
Report’ for 1894. material.
With regard to the general form of the complete frond of D. pristis and D.
plete paper fully illustrated. His previous views are here
repeated and amplified, but in afew cases they are somewhat
Ruedemanni, which consists of many stipes arranged so as to radiate outwards from a
central point—the funicle, these stipes are of three different lengths, and are con-
nected together to an approximate central form by their virgulas, ‘‘or more
properly hydrocauli.” Ruedemann distinguishes between the virgula proper and
the hydrocaulus, ‘‘ which forms the connecting stem and is a canal containing the
virgula of the rhabdosome included in its distal part.”
’
As to the function of the central disc ‘‘ which encloses the funicle,”’ it may have
served to support the bases of the stipes, it was ‘certainly a protection to the
funicle,’ and it may have served as a float.
The basal cyst consists of “ two segments resting in the middle on both sides of
a subquadrate base, and the test is comparatively thin. The gonangia and rhabdo-
somes which proceed from the central dise and funicle, occur below the basal cyst.
Ruedemann at first regarded this organ as a “ float” or swimming bladder, and
believed that the Graptolites floated, on account of (1) the extreme length and
thickness of the hydrocaulus im some specimens, which “makes it difficult to
imagine how such an extremely thin stem could have supported the long and
broad rhabdosome in any other than a suspended position”; (2) the absence of any
evidence of the sessile nature of the colonies; and (8) their wide distribution,
which would be accounted for by their floating habit. This view of their floating
habit, however, Ruedemann relinquished in this second paper, on account of the
discovery of a large slab in which more than a hundred colonies of D, Ruedemanni
are spread out regularly. He considers that the “improbability of such an array
of nicely ordered, apparently undisturbed stellate groups having been drifted
together is obvious.” The hydrocauli and rhabdosomes possess only a very slight
flexibility, and therefore it was only where there were no currents in the sea that
one could hope to find entire colonies.
He abandons the floating theory previously held by him, and suggests that the
basal cyst was “buried in the detritus” on the floor of the ocean, and served to
procure stability for the colony.
He compares the gonangia or vesicles containing the sicule with certain organs
in the Sertularians, and considers that they resemble in all the more important
features the Sertularid gonangium, which contains a cylindrical column, the
“blastostyle,’ and he thinks that the possession of these organs and also their
structure are arguments for the hydrozoan nature of the Graptolites.
HISTORY OF RESEARCH. CXX1X
Ruedemann next discusses briefly the various supposed reproductive organs
described by previous authors, and suggests that the “ bi-thecee” observed by
Holm in Dictyonema should rather be compared with the nematophores of the
Plumularians than with gonangia.
He deals with the development of the sicula at some length, and considers that
while there is “conclusive” evidence that numerous sicule left the gonangia, it is
also clear that others did not sever their connection with the parent colony, but
grew out into new rhabdosomes.
The development of Diplog. pristis is worked out by him in detail, and his
results may be summarised as follows:
(1) The detached sicula is attached by means of a small round node to a basal
appendage.
(2) The hydrocaulus gradually lengthens and more and more thece are formed.
(3) ‘The node becomes the central disc and funicle. The sicula produces at
first one theca, then a second, third, ete.”
(4) The growth of the gonangia (four small capsules) begins with the budding
of the first thece.
(5) The gonangia mature and open, the sicule, however, remaining connected
with the parent colony, the basal cyst, funicle, etc., are all present.
(6) The sicule grow out to rhabdosomes.
(7) A second generation of gonangia begin to grow, and the process is
continued.
The “number and length of the rhabdosomes increase with the age of the
whole colony.”
Affinities—As respects the affinities of the Graptolites, he merely states that
they should be placed in a distinct class—the Rhabdophora.
He concludes his paper with a reply to some of the objections raised by Wiman,
especially with regard to the terms employed for the various structures. He
maintains that the “central discs” of Dichograptus and Diplograptus are “ geneti-
cally identical,” but he relinquishes the employment of the term “funicle”’ for the
connecting stem of Diplograptus. He argues also in favour of the “ gonangia”-
like nature of the capsules described by him.
1896.
Giirich, In the same year, 1896, Giirich published a paper,
“Bemerkungen zur Remarks on the genus Monograptus,” in which he discussed
Gattung Monograptus,” the structure, the shape of the thecal aperture, and also the
‘ Zeitsch. d. deutsch. . . .
biology of the Monograptidee in general.
geol. Gesell.,’ vol. xlviii. By gral S
As regards the histology of the Graptolite skeleton, he recognises the four
structural layers described by Perner, but considers that the appearances are
capable of a different explanation. He adds many new facts regarding these, and
is “not the organic structure of a special
5)
considers that the layer “ with coigns ’
s
CXXX BRITISH GRAPTOLITES.
layer of the rhabdosome wall, but a peculiar calcite deposit formed during the
process of fossilisation, the formation of which was only possible when the skeleton
of the rhabdosome wall—namely the black layer—was surrounded by an organic
integument.”
The * palisade” layer (layer with colonnettes) he also regards as another form
of the calcite deposit surrounding the black layer. Giirich concludes from his
investigations that the chitinous skeleton of the rhabdosome in the living condition
was surrounded by a skin, but that it 1s impossible to say of how many layers
this skin consisted, or what were their particular histological peculiarities. The
existence of such an outer skin is proved by the presence of growth-lines, and the
chitinous skeleton, instead of being external, is mesodermal. ‘These conclusions of
Giirich are in accordance with Wiman’s views (‘ Ueber die Graptolithen,’ 1895).
The form of the aperture in Monograptus priodon is dealt with, and Giirich
disputes Jaekel’s idea of a laterally expanded projection, pointing out that the
theca in this form is merely a “tube whose open oval end is bent back towards
the sicula.” He gives a figure showing a schematic reconstruction of the cells of
this species.
The paper concludes with remarks on the mode of life of the Monograptide.
He considers that it is very improbable that they were attached to the sea floor,
and argues that their geological distribution, their method of preservation, etc.,
speak in favour of their being Plankton.
Ruedemann’s discovery of colonies of Diplograptus justifies us, he considers, in
concluding that the Monograptidz possessed a swimming bladder, and also that a
large number arose from one and the same stock. In this case the relationship
between the rhabdosome, sicula and disc becomes of primary importance, the form
of the aperture is secondary, and is the result of such a relationship. He re-
figures and discusses his schematic representation of the differences between the
Monograptus erecti and M. reverst groups.
In 1896 Gurley published a paper entitled ‘North
1896.
Gurley, American Graptolites,’ in which he gives a complete list of
“ North American American forms, discusses the synonymy of many of the
Graptolites,” “Journ. genera and species, and describes a large number of new
Geol.,’ vol. iv, no. 1. : x £
species, without, however, figuring them.
Description of Species—The followmg forms are referred to or described:
Phyllograptus ? eambrensis, Dryograptus? multiramosus, Dichograpsus remotus, D.
abnormis, Tetragrapsus acanthanotus, Didymograpsus bipunctatus, D. perflexus,
D. geminus, D. hirundo, D. convexus and D. sagitticaulis.
The generic name Stephanograptus should, he considers, take precedence of
Helicograptus and Ceenograptus: two new species are described: S. crassiusculus
and S. exilis. Azygograptus is represented doubtfully by one species 4. ? Walcottt.
HISTORY OF RESEARCH. CXxxl
Other forms noted are Leptograptus ? macrotheca, Dicellograptus intortus var. poly-
thecatus, D. Gurleyi, D. elegans; Dicranograptus furcatus, D. Nicholsoni, vav.
arkansensis, var. whitianus, var. parvangulus, var. diapason; Climacograptus
antiquus, C. caudatus, var. laticaulis, CU. oligotheca, C. cwlatus, C. phyllophorus ;
Diplograpsus stenosus ; Glossograptus arthracanthus; Lomatoceras (he thinks that
this name has clear priority over Monoprion or Monograptus, and so far as he can
ascertain has never been used for the name of an insect); Gladiolites (instead of
Retiolites) venosus ; Reteograptus Geinitzianus ; Dictyonema cf. neenah, D. perexile,
(=D. delicatulum, Dawson, preoccupied), ). actinotum, D. Blairi; Desmograptus
macrodictyum, J). devonicus ; Dendrograptus unilateralis, ). arundinaceus, D. cf.
serpens.
Gurley describes three species of Caryocaris which “from its resemblance to
Dawsonia may be a Graptolite”; the species are C. Wrightii, C. oblongus,
and C. curvilatus. Dawsonia is represented by two new species: D. monodon
and D. tridens. A new genus—Phycograptus—is proposed and two species of
this genus are described: P. brachymera and P. levis. Thamnograptus Barrandi
is also referred to, and it is suggested that the “thecze appear to have been
excavated out of the substance of the branch.”
1896. The second part of this paper, which was published three
Gpnley, months later, deals mainly with the “ Vertical Range of the
“ North American ; jf : ; ;
Gentolien = youn Graptolites in America,” and detailed tables are given,
Geol.,’ vol. iv, no. 3. | Showing their distribution and range.
In addition, a new species is described, viz. Diplograpsus Ruedemanni, being
one of the forms mentioned by Ruedemann as D. pristiniformis in his paper on
the ‘‘ Mode of Life of the Graptolites.”
1896.
Elles and Wood,
“On the Llandovery
and Associated Rocks including the zone of Ltastrites maximus. They also found
In 1896 Elles and Wood recorded the existence of an
Upper Birkhill graptohtic fauna at Conway, North Wales,
of Conway,” ‘Quart. representatives of the faunas characteristic of the overlying
2 1 5) ~
Journ. Geol. Soe.,’ vol. Tarannon and Wenlock Shales.
ln.
In the year 1896 T. 8S. Hall recorded the existence of
ree: . Ordovician Graptolites from two or three localities in North-
Hall, T. 8.,
Eastern Victoria.
“On the Occurrence of ; es f ; :
He considers that judgmg from the species of Dicello-
Graptolites in North- ‘
Eastern Victoria,” graptus, Dicranograptus, Diplograptus and Climograptus identi-
‘Proc. R. 8. Victoria,’ fied by him the beds appear to belong to the “ higher part of
vol. ix (new series). the Ordovician.”
In 1896 Wiman published the results of his researches on the structure of the
Dendroidea by a paper on a new species of Dictyonema—D. cavernosum.
CXXXIl BRITISH GRAPTOLITES.
eon He gives special attention to the structure of the proximal
Wiman, : 7
“Ueber Dictyonema attachment (“ haftscheibe ”’).
end and shows how the first thecz originate from the disk of
cavernosum,” ‘Bull. By means of cross sections he finds that two individuals
Geol. Inst. Upsala,” of different sizes appear to arise from the disc of attach-
poly oth eons ment, and he gives various explanations as to their origin.
He inclines to the view that the larger individual was the older and was
originally free-swimming, and that from it the smaller budding individual was
developed. Another explanation which he considers probable is, that both thecee
were produced from an older and non-chitinous individual which was originally
free-swimming.
1897.
Tornquist, In 1897 Térnquist published the first part of his Mono-
“On the Diplograptide graph on “The Graptolites of the Rastrites Beds.” In this
and the Heteroprionide
of the Scanian Rastrites : : 5
Beds,” “Acta Reg. Soe. and describes and figures several species of Diplograptus and
he deals with the Diplograptide and the Heteroprionide,
Physiog. Lund.,’ vol. | Climacograptus, some of which are new to science.
Vill.
Description of Species—The descriptions and illustrations are excellent, and
are specially concerned with the elucidation of the detailed structure of the
proximal end, which had previously remained almost unnoticed. The species
described include the well-known forms: Climacograptus scalaris, C. rectangularis,
C. wndulatus, Diplograptus palineus, D. folium, D. acwminatus, D. cometa, D.
tamariscus, D. bellulus, D. longissimus, and in addition two new species: Climacog.
medius and Diplog. cyperoides, and a new varietal form, Dimorphog. Swanstona
var. Kurcki.
Tornquist considers that “at present it is advisable to retain the genus Diplo-
graptus undivided,” and he therefore does not adopt the sub-generic names of
Petalograptus and Cephalograptus.
Terminology.—Térnquist discusses various questions of terminology, and
endeavours to bring the nomenclature employed by Wiman, Holm and himself
into uniformity. He considers that the terms “obverse”? and “reverse”’ aspects
are hable to less ambiguity than those of “sicula”’ and “ anti-sicula” side, and he
also prefers the names “ primary” and “secondary” to the “left” and “right”
for distinguishing between the two series of thece. He proposes the term
“prolific side ” for that side of the sicula which “ communicates with the proximal
cavity of the rhabdosome.” 'The opposite side he calls the “ dorsal” side.
He also suggests the new name “virgella” for the “so-called proximal
prolongation of the virgula.”
He discusses in some detail the question of the exact application of the words
“ thecz ”’ and “common canal,” and thinks that the term ‘“‘ theca” is a convenient
HISTORY OF RESEARCH. CXXxill
one for that part of the common chamber “ which is capable of being broken off.”
He therefore considers that it is “advisable to retain the word theca in its
original sense,” and if a new word be necessary, to give one to ‘‘that portion of
the periderm which corresponds to an individual zooid once living within” (that is
to say the theca and its contributory part of the common canal combined).
Although Toérnquist agrees with Holm that the sicula is the covering of the
first zooid, he considers it very advisable to distinguish “im practice, between sicula
and thece,” and therefore does not apply the term “ first theca” to the sicula.
Range and Distribution —Tornquist prefaces his paper with an account of the
seven Graptolite Zones in the Rastrites Beds of Scania. These are very similar
to those given by Tullberg, with the addition that the lowest zone, 7. ¢. that of
Diploqraptus acuminatus, is here recognised in Scania for the first time.
ae In 1897 Perner published the first section of the pure
pee part of his Monograph on the “ Graptolites of Bohemia.
« Btudes sur les Grap- This part contains a description of the species of Graptolites
tolites de Boheme,” — found in the lower layers of the band E.i., which corresponds
Prague, pt. i, to the Llandovery-Tarannon beds of England.
oe: Description of Species.—In the genus Diplograptus Perner
describes and figures the well-recognised species of Diplograptus palmeus,
D. bellulus, D. (Glyptograptus) vesiculosus, D. tamariscus, D. sinuatus, D. ovatus, and
D. modestus.
In the genus Cephalograptus he includes C. cometa and OC. foliwm.
The genus Climacograptus comprises CO. phrygionius, C. scalaris, and the new
species C. bohemicus.
Rastrites is represented by R. Linnei (= R. fugax, Barr.), Rh. peregrinus,
including two new varieties, var. longispinus and var. approximatus, and a new
species, J’. Richteri.
The group of Leptopodes in the genus Monograptus includes M. argutus,
M. attenuatus, M. cyphus, M. limatulus, and a new species, M. tubiferus.
In the group of the Orthopodes Perner describes M. leptotheca, M. Hisingert,
M. crenulatus, M. Sedgwicki, M. Halli, and a new variety of M. jaculum, t.e. var.
variabilis.
The group of Helicopodes contains M. planus (= M. reswrgens, Linnars.), M.
convolutus, M. proteus, M. triangulatus, M. tuwrriculatus, M. communis and a new
species, M. mirus, Barr., sp. ms.
In the group of the Opisopodes, Perner discusses at some length the exact
identity of Monograptus Becki, and shows that Barrande had confused three dis-
tinct forms, all from different zones, under this single specificname. He refigures
the true M. Becki and also describes M. lobiferus, two new varieties (var. Lapworthi,
and var. undulatus), WM. runcinatus, M. crispus, M. deatrorsus, M. distans, M.
Clingami, M. (Rastrites) gemmatus, and the following new species: M. retusus,
CXXX1V BRITISH GRAPTOLITES.
M. Marri, M. Holmi, WV. densus, M. Nicholsoni, M. Clingani var. tenera, and
var. Hopkinsoni.
The group of Kamptopodes contains M. nuntius.
The genus Retiolites is represented by Rk. perlatus and I. obesus.
1897. In the year 1897, Walther, of Jena, published in the pages
Lapworth, of the ‘ Zeitschrift der deutschen geologischen Gesellschaft’
“Die Lebensweise der a memoir on the “ Mode of Life of Fossil Sea Animals.”
Graptolithen,” in
Walther’s
“Ueber die Lebensweise
fossiler Meeresthiere,”’
‘Zeitsch. d. deutsch, he had already dealt with the classification of the Graptolites
geol. Gesell.,’ vol. xlix, in 1873, and their distribution in 1879-80.
Heft. 2.
This memoir includes (pp. 238-258) an article by Lapworth
on “ The Mode of Life of the Graptolites.” In this, Lapworth
dealt with this subject in the same comprehensive manner as
He adduces the facts known with reference to the relative
distribution of the Graptolites in the various types of sediment within the British
Isles, and shows that these facts go to prove that :
(1) The presence of Graptolites in any of our British rock-layers stands
in some way related to the presence of carbonaceous matter in the sediments in
which the Graptolites occur.
(2) Although Graptolites are found in all our Proterozoic sediments, yet they
are normally and typically restricted to regions where much carbonaceous matter
was deposited.
(3) The relative abundance of Graptolites in any single layer or rock-group is
im some way connected with the calm of the sea-floor where the carbonaceous
deposits were laid down (for the material in which the Graptolites lie embedded
is usually so impalpable in grain that the gentlest current would have removed it) ;
and that the most typical and richest British Graptolite-bearing beds are those
which accumulated at the slowest rate.
It is next shown that the Graptolites themselves did not supply the car-
bonaceous matter in the sediments, nor did they live where they are now found.
The carbon-producing organisms must also have been strangers to the locality, and
it is inferred that these must have been floating sea-weeds.
The distribution of the black sediments and their thinness both point in the
same direction ; they are deposits formed mainly from the relics of floating sea-
weeds, arranged in quiet waters parallel to the shore, having been drifted by
currents and sinking when waterlogged to the bottom. The presence of Grapto-
lites associated with these is in harmony also with the abundance of Hydroid
organisms living on the fronds of the Sargassum sea-weed of the present day,
which have been drifted from the shore, and become accumulated in special
regions of the ocean or swept by currents into almost all latitudes.
These conclusions being conceded, we have what appears to be the clue to the
mode of life and the general line of evolution of the Graptolites, including both
HISTORY OF RESEARCH. CXXXV
virgulate and non-virgulate forms. The Cladophora or non-virgulate forms, like
the modern Sertularians and their allies, must have been fixed to rocks in the
shallow parts of the sea-shore, and therefore stationary, or to floating objects of a
comparatively large size. The Rhabdophora or virgula-bearing Graptolites, on
the other hand, were attached to floating sea-weeds, and were therefore drifted far
and wide over the waters of the sea at the mercy of winds and currents. ‘The non-
virgulate forms grew vertically upwards, and like their modern representatives,
were more or less tree-lke. The virgulate forms hung vertically downwards,
being pendent to the under side of the sea-weed by a thread-like fibre, which in its
earliest stages constituted the “‘nema’”’ proceeding from the apex of the sicula, and
which, in the later forms of the Rhabdophora, growing with the general growth of
the rhabdosome, constituted the “solid axis or virgula.” In other words the
Rhabdophora form a special section of the Graptolites, modified for a pseudo-
planktonic mode of existence. The modification commenced in later Cambrian
times, within the limits of the genus Dictyonema. Some forms of this genus are
provided with a short stem and a dise of attachment, and some examples, even of
the same species, may have grown vertically, while others may have assumed a
pendent position. Abundant examples, however, are met with in which the stem
is lengthened out into a long, thread-lhke hydrocaulus or nema. In these forms
the pendent mode of attachment is the only one possible. In harmony with this
we find that once this change from dendroid to pendent is initiated, the Graptolites
become world-wide in their distribution and remarkable for their abundance.
In the successive stages of the evolution of the Rhabdophora in time, the
number of branches is gradually reduced, and they become turned more and more
backwards and upwards towards the light. A first stage is typified by the oldest
family (the Dichograptidz), in which the nema is lengthened, and within the limits
of which the branches bearing thece, originally turned downwards owing to their
pendent position, turn in the successive genera backwards and upwards towards
the line of the nema. The angle of divergence of the branches gradually
increases thus from 0° to 360°, and in the Phyllograptide the branches, which by
this time have been reduced to four in number, attach themselves to each other
dorsally and grow backwards up the line of the nema, and the thecze have
practically recovered their upward direction.
In a succeeding stage (the Diplograptide) the branches are reduced to two in
number, and the nema, which apparently lengthens with the growth of the
organism, has become a typical virgula.
In the final stage (the Monograptidz) the branches are typically reduced to one,
and the evolutionary series is closed.
It is pointed out that difficulties exist, especially as regards the Dicello-
grapta (Leptograptide and Dicranograptide), but if it be accepted, even as a
broad generalisation, that the typical nema- and virgula-bearing Rhabdophora were
CXXXVl BRITISH GRAPTOLITES.
pendent forms attached to floating sea-weed, this generalisation harmonises the
previously known facts as respects their special mode of occurrence, their universal
dissemination, their superabundance in carbonaceous deposits, their restricted
geological range, and their broad lines of evolution in time.
1897.
Frech, In 1897 Frech published an extended monograph on the
“Lethea Geognostica,” Graptolites in general, in his continuation of Roemer’s great
EN CN SLE OBOE work ‘ Lethza Palzozoica,’ which was left unfinished at his
Roemer’s ‘ Lethea
; death.
Palzozoica,’ vol. 1.
In addition to epitomising and illustrating the discoveries and conclusions of
previous observers, Frech made many new theoretical suggestions, especially as
regards the classification of the Graptolites.
Organisation of the Graptolites.
Frech commences with discussing the organisation of the Graptolites, dealing
first with :
A. Organisation of the Fully-grown Animal.—Broadly speaking, he adopts the
views of Ruedemann with relation to the so-called pneumatophores, gonangia, etc.,
and extends them to all the Diplograptide. In the Dendroidea, however, he
regards the gonothecz of Wiman and Holm as corresponding to the nematophores
of the Hydrozoa.
As regards the structure of the test, Frech does not adopt Perner’s view of the
existence of a fourth layer.
Frech lays great stress on the free-swimming or floating character of the
Rhabdophora, and explains many of the peculiar structures found in Graptolites
by the assumption that they were connected with their swimming mode of life.
He recognises four different modifications of swimming organs :
1. The bladder in Diplograptus physophora is a “ rudder-lke propelling organ.”
The same is the case with the vesicle in Monograptus pala, of which he gives a
theoretical drawing of colonies attached to a float. 2. The so-called disc at the
base of Climacograptus bicornis he regards as having served in some way for the
movement of the animal. 38. A third modification is found in Cephalograptus,
where the “‘ whole surface of the hydrothecee has widened and taken on a rudder-
like form.” He gives a theoretical drawing of Petalograptus foliwm attached to a
float. 4. A fourth modification occurs in Dicellograptus divaricatus, in which a
membrane exists between the branches.
All these aided in giving the Plankton colony-animals an undulating up-and-
down movement rather than a forward one. As it is doubtful whether all the
Monograpti possessed floats, the “ float,” therefore, must not be regarded as an
organ of systematic importance. In those forms that have a float, “the axis
HISTORY OF RESEARCH. CXXXVIl
is the rudder-stem, and the float itself the rudder-fins;” the fixed Dendroidea
have no such organ.’
Frech does not regard the spine-like appendages to the apertures of the cells,
as found in the Glossograptidz, as of systematic importance, but as protective
organs, “ perhaps also sensory.”
Frech divides the Graptolites into two main groups, differing from each other
in the development of the axis, the rudder floats, and common canal, and also in
their embryonic stages.
Orver 1: Axonophora.—This includes Diplograptus, Climacograptus, Dicrano-
graptus, Dicellograptus and Monograptus. The sicula is distal in position, and the
later polyps insert themselves between the apex of the sicula and the central
bladder. The apertures are directed inwards (proximally), a virgula is present,
a common canal absent. The mode of life is planktonic, with a passive or active
movement.
Orper 2: Avonolipa.—This includes the Dichograptidze and the Dendroidea.
The sicula is proximal, and the younger cells grow distally, their apertures being
directed outwards. A common canal for the ccenosarc exists in the Dichograptide,
but not m the Dendroidea. “ A virgula has not been observed in any of the main
types of this order, in spite of numerous microscopic sections.”
The Retiohtidi, according to Frech, correspond in the structure and arrangement
of the hydrothece, and in the presence of an axis, to Diplograptus ; and [etiolites
is a “younger derived form” of that genus. As regards the Dendrograptidi,
Frech accepts Wiman’s opinion that they had no axis, and he considers that
there are many points of contact between the Dendrograptidi and the Dicho-
eraptidi.
B. Hmbryonal Development of Graptolites.—Frech gives a summary of
Ruedemann’s and of Wiman’s work, and accepts their conclusions. As regards
Ruedemann’s work, he seems to think that in addition to the primary hydro-
rhabdosomes, there should be “secondary hydro-rhabdosomes,” arising direct
from the proximal part of the virgula, or from the central plate, and having no
sicule, thus producing a colony like that seen in Letiograptus, and he tries to
account for the paucity of these non-siculate secondary hydro-rhabdosomes.
Frech emphasises strongly his opinion that “an analogy exists between the
development of the Axonolipa and the Tabulate Corals,” while “the embryonal
polyp of Phyllograptus has the greatest similarity to the primary calyx of
Pleurodictyuwm.” He considers that the terms “ Hydrozoa” and “ Anthozoa,”
which are founded on living forms, are in no way applicable to their Palzeozoic
ancestors. He places the Graptolithide as the third member of the following
series :
(a) 1, Archarocyathinia. (8) 2, Acalephe; 3, Graptolithide ; 4, Tabulata ;
5, Stromatoporoidea. (c) 6, Pterocorallia, All except the first and last ‘“ take
t
CXXXVII BRITISH GRAPTOLITES.
the place of the modern Hydrozoa, and are perhaps phylogenetically related
to them.”
C. The Position of the Graptolites in the Zoological System.—The Axonophora
and Axonolipa are very distinct, the only point of similarity between them being
the form of the sicula. He discusses at great length the relationship of the
Graptolites to the Sertularians, but thinks that all the resemblances are superficial.
Between the Dendrograptidi and living Plumularians, however, there is much direct
relationship in the organisation of the grown animal, and the only main distinction
between them is the want of a common canal in the former, and the shape of the
embryonic polyps.
D. Classification.—The classification adopted by Frech differs in many respects
from that proposed by British and Swedish workers, and the number of genera
and species, are, in the majority of cases, materially decreased. His classification
is as follows:
Orver I.—AxXono.ipa.
1. Dendrograptidi.—(Hydrotheez dimorphous, larger nutritive and smaller
protective polyps, branching irregular.)
(a) Dictyonema.—Nineteen species are recorded, and D. flabelliforme and
D. tuberosum are re-described.
(b) Callograptus.—C. Salteri and C. elegans are described.
(c) Dendrograptus.—Nine species are recognised and several figured.
(d) Ptilograptus.—Four species are recognised, and P. acutus is described
and figured.
(Frech considers that Thamnograpsus, Inocaulis and Corynoides are “ imcom-
pletely known, and their systematic position uncertain.”’)
2. Dichograptidi.—(This includes the Dichograptide, Leptograptide, and the
Phyllograptide.) Free-swimming hydrothece, one kind only, branching dicho-
tomous.
A. Sub-family Didymograptini (two main branches) :
(a) Bryograptus.—B. Kjerulfi (= B. Callavet), B. retroflerus, B. ramosus,
B. Hunnebergensis and B. sarmentosus. (He gives a table showing
the phylogenetic relationship of the genus.)
(b) Cenograptus s. str.. OC. gracilis and C. fragilis, and including
T'richograptus.
Pterograptus, sub-gen.—P. elegans.
Pleurograptus, sub-gen.—P. linearis, Amphigraptus (A. divergens).
(c) Didymograptus—In the group of D. Murchisoni he includes
D, Murchison var. gemina, D. dentatus (indentus), D. v-fractus,
D. nitidus ; in the group of D. flaccidus (Leptograptus ex parte),
D. extensus, D. minutus, D. jlaccidus ; and in the group (or sub-
genus) of D. gibberulus that species only.
HISTORY OF RESEARCH. CxexIx
B. Sub-family Tetragraptini (four main branches).
(a) Dichograptus.—D. octobrachiatus and D. Logan.
Temnograptus, sab-gen.—T'. Milesi, T'. reticulatus, 1. annulatus, 1.
diffusus, ’. eepansus, T'. Richardson, and a new species, 7’. Barroisi
(=Rowvilligraptus Richardsoni, pars).
Clonograptus, sub-gen.—C. tenellus, C. flewilis, C. rigidus, C. multa-
fasciatus, C. Thureaua.
(b) Tetragraptus.—In the group of 7’. Bigsbyi,—T'. Bigsbyi, T. bryonoides,
T. denticulatus, T'. fruticosus, and 7. octunarius. In the group of
T'. Headi,—T. Head, T'. alatus, T. quadribrachiatus.
c. Sub-family Phyllograptini (four main branches which grow together dorsally).
Phyllograptus.—P. typus, P. Wicifolius, P. Anna, P. angustifolius, P. Loringt.
Orper IT: AxonopHora.
3. Climacograptidi.—(Hydrothece at right angles, outer edge straight, indented
by the thecal apertures.) This includes, in addition to Climacograptus, the
Dicranograptide, and the Glossograptidee.
(a) Letiograptus.—R. eucharis, R. tentaculatus, R. ? Geinitzianus.
(b) Climacograptus—The group of C. bicornis includes CU. bicornis, the
new species CU. Nicholsoni, and C. antennarius. The group of
C. scalaris, C. Scharenbergi, C. typicus, C. estonus mut. Kucker-
sianus, CO. estonus, O. scalaris, OC. caudatus, O. internexus, C. Wilsone
and CU. retiolowes.
(c) Dicranograptus.—D. ramosus, D. Clingaii, D. Nicholsoni.
Dicellograptus, sub-gen.—D. anceps, D. complanatus, D. divaricatus,
D. Morrisi, D. moffatensis, D. intortus, D. Forchammert, D. patulosus,
D. sextans, D. elegans.
(d) Monoclimacis, n. ¢—Rhabdosome with only one row of cells, hydro-
thece like Climacograptus. M. vomerinus, M. personata, M. crenu-
laris, M. continens, M. spinulosa.
The genus T'rigonograptus probably belongs to this group.
4, Diplograptidi.im(Rhabdosome with two rows of cells; hydrothecae oblique ;
outer edge toothed.)
(a) Diplograptus.—
Group I includes D. pristis, D. foliaceus, D. teretiusculus, D. sertularcides
n.s., D. physophora, D. bellulus, D. gracilis, and D. palmeus.
Group IT (=Glossograptus) mcludes D. Whitfield, D. wplandicus and
D. cf. aculeatus.
Glyptograptus, sub-gen.—D. amplexicaulis, D. tamariscus.
Orthograptus, sub-gen.—O. quadrimucronatus.
Petalograptus, sub-gen.—P. foliwm mut. ovato-elongata, P. foliwm, and
P. ovatus.
ex] BRITISH GRAPTOLITES.
Cephalograptus, sub-gen.—C. cometa.
(b) Dimorphograptus.—D. elongatus, D. Swanstont.
5. Monograptidi.—(Rhabdosome with one row of cells, rarely branched. Hydro-
thecz of many kinds.)
(a) Rhabdosome simple :
i. Monograptus.—(Hydrothece of many forms and bent round in a
distal direction, attached to the axis.)
In the group of M. priodon he includes M. priodon mut. Clintonensis
var. Hlemingi, M. galensis, M. riccartonensis, M. cultellus.
In the group of M. Bechi,—M. Becki, M. cygneus, M. scanicus, M.
Barrandei, M. attenuatus.
In the group of M. runcinatus,—M. runcinatus, M. dextrorsus, M.
nodi fer.
In the group of M. twrriculatus,—M. turriculatus, M. proteus, M.
spiralis, M. triangulatus. In addition he describes M. resurgens
and M. Clingant.
i. Pristiograptus.—(Hydrothece, asin Diplograptus, neither elongated
nor bent round.)
In the group of P. frequens he includes P. frequens, P. dubwus,
P. colonus, P. Toemeri, P. jaculum, P. Hisingeri, P. leptotheca,
P. uncinatus, P. leintwardinensis, P. pala.
In the group of P. gregarius,—P. gregarius, P. cyphus.
In the group of P. testis,—P. testis, and P. discus.
il. Linograptus n. g.—(Like Pristiograptus, but the sicula and hydro-
thecee both open distally.) L. Nilssont, L. concinnus, L. Sander-
sont, L. tenuis, L. bohemicus.
iv. Rastrites.—(Hydrothece straight, not connected with the axis.)
Rh. Linnei, R. maximus, R. fugaw var. distans, R. peregrinus,
R. hybridus, R. gemmatus, R. capillaris, R. Barrandet.
(b) Rhabdosome branched :
Cyrtograptus.—C. Grayie, C. Murchisoni, C. rigidus, C. pulchellus,
CU. Linnarssoni, C. Carruthersi.
6. Retiolitidi.—(Rhabdosome with two rows of cells, perisare consisting of a
network of chitinous threads.)
(a) (Hydrothece oblique) :
1. Retiolites.—R. Geinitzianus, I. venosus, R. australis.
u. Stomatograptus, sub-gen.—N. grandis.
in. Lasicgraptus.—L. bimucronatus, L. costatus, L. margaritatus.
(b) Gothograptus, n. ¢.—(Hydrothece vertical.) G. nassa.
The range and distribution of the Graptolites and dealt with in some detail, and
a table is given of their geological distribution.
HISTORY OF RESEARCH. exh
In 1897 Elles published a paper on the “ Sub-genera
ane Petalograptus and Cephalograptus,’ mm which she adduced
“The Sub-genera evidences that these sub-genera are quite distinct, and readily
Petalograptus and distinguished the one from the other. She worked out care-
Cephalograptus,” fully the structure of the various species belonging to the
‘Quart. Journ. Geol.
Sa eee sub-genera, especially that of the proximal end, showimg that
oc., vol. lim.
it differs in important particulars in the two groups.
From her study of these species she concludes that the Petalograpti have been
derived from Orthograptus foliaceus through O. truncatus, and the Cephalograpti
direct from the Petalograpti, Cephalograptus petalum being the intermediate form.
Description of Species—The following species are re-described in detail and
re-figured, Pelalog. foliwm, P. palmeus, var. latus, var. tenuis, and var. ovato-
elongatus, P. ovatus, Cephalog. cometa, and two new species, P. minor and CU.
petalum.
In this year also Wiman gave a further account of his
1897.
Wiman,
‘“‘ Ueber den Bau einiger
extended researches on the structure of the Graptolites
describing and figuring a large series of cross-sections which
Gotliindischen Grapto- he had made of some Graptolites from Wisby in Gothland
liten,” ‘Bull. Geol. preserved in silicified limestone.
. aq ]y 7 117 0 ¢
Inst. Upsala,’ vol. iui, He figures a good specimen of Dictyonema cavernosum
art. no. 10. . : : - 7:
provided with stolons, one of Dictyonema (2) tuberosum and
one of Climacograptus. Other forms dealt with are isolated specimens of
Dendroidea, which, however, he does not attempt to refer to definite species.
In a paper read before the Durham Philosophical Society
1898. : :
A. Meek summarised the researches of Holm and Ruedemann
Meek, A.,
“On Graptolites,”
‘Proc, Univ. Durham _ lites.
Phil. Soc.,’ vol. i, pt. 2. He lays stress on the supposed absence of a virgula in the
Dichograptidz, and suggests that as they “do not seem to
have possessed a means of fixing themselves,” “it must be supposed that they
had the power of movement and temporary attachment with whatever the living
contents of the theese provided.” Forms like Phyllograptus he thinks were
“purely crawling forms—say by means of tentacles or pseudopodia.”
He tentatively suggests that the presence or absence of a virgula might form
respecting the structure and mode of growth of the Grapto-
the basis of a new classification.
1898. In 1898 T. S. Hall made a further contribution to the
Hall, T. 8., eraptolitic fauna of the Lancefield Beds, Victoria, which con-
‘ Victorian Graptolites,’ ; sacs ; ;
Pees, i firmed his original views that they underle the Tetragraptus
part , ‘“Graptolites of
the Lancefield Beds,” Jruticosus zone.
; Pantin Brie ae Sarena dened
‘Proc. Roy. Soc. Vie- Description of Species. — He describes and figures a
toria,’ n.s., vol. xi, pt.2.. number of new species of Graptolites, including Bryograptus
exli BRITISH GRAPTOLITES.
Victorie, Biryog. Clarki, Leptog. antiquus, Didymog. Pritchardi (a form occasionally
possessing three branches), ). Taylori, V'etray. decipiens, Dictyonema pulchellum,
and he re-describes and figures Clonog. flewilis, C. magiuificus, C. rigidus var. tenellus,
Phyllograptus species and Dictyonema Macgillivrayt.
According to Hall, Leptograptus and Bryograptus here occur together on the same
slabs, and he explains this unusual association by concluding that in Victoria
Bryograptus ranges up to the Ordovician.
1898.
Elles, In 1898 Elles published a revision of the Graptolite fauna
“The Graptolite Fauna of the Skiddaw Slates of the Lake District, the forms found
of the Skiddaw Slates,”
‘Quart. Journ. Geol.
Soe.,’ vol. liv.
in these rocks beme re-described, and particular attention
being paid to details of structure.
The development of Bryograptusis worked out in B. Kjerulfi, B. cf. Callavei, and
B. raimosus ; and anew variety, var. cumbrensis, is described. The following species
are described : Clonograptus fleailis, O. cf. tenellus, Clonograptus sp. ; Loganograptus
Logani; Trichograptus fragilis ; Temnograptus multiplee ; Trochograptus diffusus ;
Schizograptus reticulatus, S. tardifureatus, sp. noy.; Plewrograptus vagaus ; Ptero-
graptus sp.; Dichograptus octobrachiatus, D. separatus, sp. nov.; T'etragraptus quadri-
brachiatus, T. Headi, T. crucifer, T. Bigshyi, 1’. serra, and two new species, 7. pendens
and 7'. Postlethwaitii; Phiyllograptus ilicifolius var. grandis, noy., P. Anna, P.typus,
P. angustifolius ; Didymograptus gibberulus. The structure of this last species is
worked out in detail, and a somewhat anomalous point of structure is noticed,
namely, the apparent presence of a second connecting canal, uniting the second
theca of the primary stipe with the first theca of the secondary stipe.
The following species of Didymograptus are re-described: D. nitidus, D.
Nicholsoni, D. affinis, D. extensus, D. patulus, D. gracilis, D. fasciculatus, D. v-
fractus, var. volucer, D. indentus, var. nanus, D. bifidus.
The genus Azygograptus is considered by Elles to belong to the Dichograptidee
(comp. Wiman) rather than to the Nemagraptide, on account of the structure
of the proximal end being similar to that in the Dichograptidee. A. Lapworth,
A. celebs, A. suecicus, are re-described, together with Leptograptus sp.; Dicellog.
moffatensis ; Diplog. dentatus, D. ef. teretiusculus, D. appendiculatus ; Climacog.
Scharenbergi ; Cryptograptus ? antennarius, C. Hopkinson ; Glossograptus fimbriatus,
G. of. Hincksu, G. armatus ; Trigonograptus ensiformis, 1’. lanceolatus ; Thamno-
graptus Dovert. Some of the above-mentioned species are figured.
The range and distribution of the various species of Graptolites are given ; the
Skiddaw Slates are divided into zones and compared with similar beds in South
Wales and Sweden, the sub-divisions of the Skiddaw Slates agreeing closely with
those given by Marr in 1894.
As regards the phylogenetic relationships of the Skiddaw Slates Graptolites,
Elles agrees with Marr and Nicholson in the main, namely, that (1) the re-
a
HISTORY OF RESEARCH. exh
semblances between species of different genera are of genetic origin, and therefore
(2) of systematic value; (3) im any natural group the forms with relatively fewer
branches were developed from the more complex forms, and therefore (4) the so-
called “genera” are far more of a chronological than of a zoological significance.
She considers, however, that the various forms are “most probably the result
of development along certain special lines.”
According to her, therefore, there is a “Group relationship ” ; for example, “ all
the ‘tuning forks’ Didymograpti have been derived from what may be termed the
fruticosus type of Tetragraptus, though not all from 7. fruticosus itself.”
She divides them into two main groups, (1) those derived from Bryograptus,
(2) those derived from Clonograptus.
In the first group there are five sub-groups :
(a) Group containing Bryograptus ramosus var. cumbrensis, Tetrag.
pendens, and Didymog. indentus.
(b) Group containing Bryograptus ramosus var. cwmbrensis, Tetrag. fruti-
cosus, and Didymog. furcillatus.
(c) Group containing Bryograplus ramosus var. cwmbrensis, Tetrag. Postle-
thwart, and Didymog. bifidus.
(1) Group containing forms derived from V'etragraptus Bigsbyi.
(ec) Group containing forms derived from Bryograptus Callavei.
In the second group there are three sub-groups :
(a) Group containing Dichograptus octonarius, T'etrag. serra, and Didymo-
graptus arcuatus.
(b) Group containing Loganograptus Logan, Didymograptus octobrachiatus,
D. extensus, and Tetragraptus quadribrachiatus.
(c) Group containing T'etragraptus Headi and Didymograptus patulus.
Elles does not regard the angle of divergence of the branches as of phylogenetic
importance ; the mode of development has been simply in the direction of “failure
in dichotomous division.”
1899.
Perner,
“ Bitudes sur les Grap-
tolites de Boheme,” — pleting the descriptive part of his work. It is devoted to a
Prague, part iii, description of the Graptolites of the upper part of Stage E.
sect. b.
In 1898 Perner published the second section of the third
part of his monograph on the Graptolites of Bohemia, com-
Description of Species—In the group of the Opisopodes of the genus Mono-
graptus, he describes and figures the well-known forms: Monog. priodon, M.
riccartonensis, M. latus, M. sartorius, and M. vesiculosus, and the new species and
varieties M. priodon var. rimatus, var. validus, /. Jaekeli, /. unguiferus, and M.
Suessi.
In the group Leptopodes Perner re-describes M. Nilssoni of Barrande and
exliv BRITISH GRAPTOLITES.
clears up the previous confusion as to the exact identity of this species, showing
that Barrande had originally included three different species under this name.
The group Prosopodes includes Monog. Roemeri, M. dubius, M. colonus, M.
chimera, M. testis, MW. bohemicus, and the following new species: M. Kayseri, M.
hercynius, 1/. gotlandicus, . subcolonus, J. largus, M. transgrediens, M.
vicinus, MV. ultimus, /. clavulus, W. Fritschi, 1/. bohemicus var. rarus.
The group Helicopodes includes only Monog. spiralis var. subconicus.
The group Orthopodes contains M. crenulatus and M. vomerinus.
The genus Cyrtograptus 1s represented by Cyrtog. jflaccidus, C. Tundgreni,
O. Murchison, C. Carruthersi, and the new species (VU. tubuliferus.
Under the genus fetiolites Perner describes Retiolites Geinitzianus, R. (Gotho-
graptus) nassa, and Stomatograptus grandis.
A memoir of very great importance as regards its bearing
1899.
Praehtand Lome: on the range and zonal value of the Graptolites was published
“The Silurian Rocks of in 1899. This was H. M. Geological Survey Memoir on the
Britain,” vol. i, “Silurian Rocks of Scotland.” The officers of the Survey
Scotland. :
confirm Lapworth’s conclusions respecting the zonal distri-
bution of Graptolites in the rocks of the Southern Uplands, and employing these
fossils as zone indices, they work out and illustrate in detail the geology of the
districts in which they occur in the course of their description of the entire Upland
Sequence.
1899.
Tornquist,
In 1899 Toérnquist published the second part of his
“The Monograptide
of the Scanian Rastrites Scat ei ;
Beds,” ‘Acta Univ, Beds.” This is devoted to the study of the Monograptide.
Monograph on the “ Graptoltes of the Scanian Lastrites
Lund.,’ vol. xxxv.
Térnquist employs throughout the terminology adopted by him in the first
part of this work.
The following synopsis is given of the species of Monograptidee described,
the grouping being based mainly on the form of the polypary and the character of
the sicula and thecz.
A. All the thecee of the same type; each wholly adnate to the proximal wall of
the theca next succeeding.
(a) Sicula attaining a length of more than 4 mm; rhabdosome curved.
M. qregarius and M. acinaces.
(b) Sicula not exceeding 2 mm. in length; rhabdosome stout, straight.
M. leptotheca, M. jaculum, M. nudus, M. regularis, n. s.
(c) Sicula not exceeding 2 mm. in length; rhabdosome stout, proximally
incurved. M. inopinus, n. s.
(7) Sicula not exceeding 2 mm. in length; rhabdosome arcuate, gradually
widening from the proximal extremity. MM. tenuis.
HISTORY OF RESEARCH. exlv
(e) Sicula not exceeding 2 mm. in length; rhabdosome slender, distally
straight, or irregularly bent. M. incommodus, n. s.
B. Thecz dimorphous: the distal ones of the same type as that characteristic
of the preceding section, each of the proximal thecze wholly, or at least distally,
free from the succeeding theca.
(2) Rhabdosome gradually widening. MM. revolutus var. austerus, nov.,
M. difformis, n. s., M. cf. cyphus.
(b) Rhabdosome abruptly acquiring its normal width. M. limatulus.
c. All the thece of the same type; each being wholly, or at least distally, free
from the theca next in advance.
(a) Rhabdosome stout and straight, or only having the sicular portion
bent backward. M. runcinatus, M. priodon, M. Sedqwickti, M.
harpago, N. 8s.
(b) Rhabdosome slender, proximally arcuate, but not enrolled, distally
straight or irregularly bent. M/. elongatus, n. s.
(c) Proximal portion of the rhabdosome forming a more or less complete
flat or sub-conical spiral, or at least showing a tendency to form
such a figure; prolific side convex. J/. denticulatus, n. s., M.
jfimbriatus, M. triangulatus, M. nobilis, n. s., M. decipiens, n. s., M.
convolutus, M. subconicus.
(d) Rhabdosome coiled up in an elongated conical helix bearing thecz on
the convex margin. WM. turriculatus.
(e) Rhabdosome enrolled in a conical spiral-bearing theca on the concave
margin. M. proteus.
(f) Rhabdosome forming a narrow flat spiral, bearing thecz on the
concave margin. M. discus.
(7) Rhabdosome fish-hook-shaped ; prolific side concave. M. exiguus.
Térnquist poimts out that he does not imagine that the above arrange-
ment is “in every respect anatural one, though he is of opinion that several of the
sub-divisions may be found to coincide with true natural groups.”
1899.
Tornguist, In a short stratigraphical paper published the same year,
“Nagra anteckningar TT Synquist noticed the various localities where the Upper
om Vestergotlands hia ws ae c ;
birerilereke Caapte: Silurian Graptolitic zones are recognisable in Vestrogoth-
litskiffrar,” ‘Geol. land.
Foren. Forh.,’ bd. 21.
1899.
Bal Se In 1899 Hall published a general account of the Grapto-
é oe ae lite-bearing beds of Victoria, and their divisions, comparing
ing Rocks of Victoria, fo) ?
Australia,” ‘Geol.Mag.,’ them with those of Hurope.
dec. 4, vol. vi, no. x.
exlvi BRITISH GRAPTOLITES.
Hall describes and figures three new species of Graptolites, namely T'etra-
graptus projectus, Goniograptus macer and T'rigonograptus Wilkinsoni, and a
species of Monograptus which he does not name ; he re-describes Didymog. gracilis
and Dichog.octonarius,and re-figures Bryograptus Victorix, and Leptograptus antiquus.
He recognises four main divisions in the Lower Ordovician of Victoria :
(1) Lancefield Series, (2) Bendigo Series, (3) Castlemaine Series, and (4) Darri-
will Series. The Graptolites characteristic of each group are fully given. The
Upper Ordovician is represented in a few localities, but the Silurian contains only
one or tio species of Graptolites.
A special point dwelt upon in this paper is the apparent want of harmony
between the Graptolite zones of Australia and of Europe. Thus, in addition to
the occurrence of Bryograptus and Leptograptus in association, Hall considers that
Loganograptus appears very high up in the series, and never in association with
Phyllograptus typus, while Didymog. bifidus, which is characteristic of an Upper
Arenig Fauna in Europe, here disappears before Phyllograptus typus.
In 1900 Elles published a paper on the ‘Zones of the
ae Wenlock Shales,” demonstrating the systematic chronological
“The Zonal Classifica. ®trangement of the various species of Graptolites in the
tion of the Wenlock | Wenlock Rocks of Britain. A few new species were described,
Shales of the Welsh and many already well-known forms, all with special regard
Borderland,” ‘Quart. to the structure of the proximal end.
Journ. Geol. Soc.,’
lly Under the species Monograptus Flemingit Elles recognises
vol. lv1. : :
four varieties, a, B, y, and 8, which are valuable zonally, as
they are practically confined to certain definite horizons. The same is the case
with M. vomerinus, of which she recognises three varieties; M. flexilis, M.
irfonensis, and M. testis var. inornatus, are new forms. A new species of
Cyrtograptus, OC. symmetricus, is also described.
The Wenlock Shales are worked out in (1) the Builth district, (2) the Long
Mountain, and (3) the Dee Valley. Elles finds that in the Builth district they
are capable of division into six zones characterised by species of Cyrtograptus, and
that the majority of these Wenlock zones are also to be found in the other areas.
The evidences adduced in this paper prove for the first time in Britain, that the
Wenlock Shales are as capable of Graptolitic zonal division as are the Birkhill
Shales, and that these British Wenlock zones run parallel to the Wenlock zones
already suggested by Tullberg for Scandinavia.
1900. In the same year Wood worked out the Graptolitic. fauna
Wood, of the Lower Ludlow Shales, and proved that these were
Eve horas lenis equally capable of division into Graptolite zones.
Formation, and its piers eee 5 Athos :
Graptélite Raat? Range and Distribution—tIn this paper the distribution
‘Quart. Journ. Geol, Of the Ludlow Graptolites is first worked out in the typical
Soe.,’ vol. lvi. Ludlow District, and four zones are recognised. Similar zones
HISTORY OF RESEARCH. exlvu
are afterwards shown (with the addition of a fifth zone) to hold in the main in the
Builth District and Long Mountain area of the Welsh Borderland. Brief notes
are also given of the Ludlow graptolitic fauna in the Dee Valley, the Lake
District, South Scotland, Dudley, and the Abberley Hills.
Description of Species.—The following species, which had been already named
by previous observers, are re-described and re-figured :
Group I.—M. dubius, M. twmescens var. minor, M. gotlandicus, M. ultimus.
Group II.—M. colonus var. ludensis, M. Roemeri.
Group IIT.—M. chimera var. Salweyi, M. leintwardinensis.
Group IV.—M. wieinatus var. micropoma.
Group V.—WM. scanicus.
Group VI.—Gothograptus nassa, M. Nilssoni, M. bohemicus.
The following new species are figured and described: M. vulgaris, var. a, var.
b, WV. tumescens, M. comis, WM. colonus var. compactus, MV. varians, var.a, var. b,
var. pumilus, WM. chimera var. a, M. leintwardinensis var. ineipiens, M. wncinatus
var. orbatus, MV. crinitus, [etiolites spinosus,
1900.
Lapworth, H.,
«The Silurian Sequence
of Rhayader,” ‘ Quart.
Journ. Geol. Soc.,’
vol. lvi.
He shows that in the district of Rhayader there occur representatives of all the
Llandovery-Birkhill Graptolitic zones as well as of the Tarannon; these zones are
A third paper of especial stratigraphical importance
was published durimg this year by H. Lapworth on the
“Silurian Sequence of Rhayader.”
mapped by him in detail.
He deseribes and figures three new species: Climacograptus parvulus, C.
extremus, and Diplograptus magnus, and gives a description of Diplog. imodestus,
which had previously been figured only.
1900. In the year 1900 Hall published the results of his exami-
Hall, T.S., nation of a collection of Graptolites made by Mr. E. F.
“On a Collection of
Graptolites from
Pittman from Mandurama.
Mina eanis > GREORAS Hall describes and figures three forms which he considers
Geol. Survey, N.S. 2¥@ new, but only names two, namely, Climacograptus affinis
Wales,’ vol. vii, pt.1. and Diplograptus mandurame.
eer In 1901 Newton described and figured a slab of Grapto-
Newton: lites collected by Mr. Jessop from the province of Carabaya,
“Note on Graptolites Peru. The species to which these belong is uncertain, but
from Peru,” ‘Geol. they closely resemble Diplograptus truncatus, Lapw. They
Mag.,’ dec. 4, vol. vii, aye “indicative of beds near the uppermost part of the
NO. Vi. . .
Lower Silurian.”
In the year 1901 Térnquist published the results of his researches on
the Phyllo-Tetragraptus beds of Scania and Vestrogothland, and recognised
exlvii BRITISH GRAPTOLITES.
in these beds for the first time the existence of five distinct
901.
ae se ZONES :
Tornquist, ; Ti ay BS AT fee
1 Geaptolites of thé (a) Zone of ich agraptus pin llograriontes:
Lhawen Zoncsonihe (b) Gone of Didymograptus balticus.
Scanian and Vestro- (c) Zone of Phyllograptus densus.
gothian Phyllo-Tetra- (d) Zone of Isograptus gibberulus.
graptus Beds,” ‘ Acta
Univ. Lund.,’ vol.
Xxxvii, pt. 2, no. 5.
(e) Zone of Phyllograptus cf. typus.
The Orthoceras Limestone intervenes between the last
two zones, and therefore the contrast between the faunas
of these zones appears to be greater than between the others.
Before proceeding to the description of species, Térnquist suggests and
explains certain terms which he employs throughout this paper.
The branch which “issues on the same side of the sicula as the first theca,”
he calls the “ primordial stipe,” the other he names the ‘ complemental stipe.”
He also distinguishes between the various parts of the first theca, and
designates them: (1) The “initial portion,” (2) ‘“ramifying portion,’ and
(3) “ apertural portion,” or true theca.
Térnquist again points out that there has been considerable confusion in the
employment of the term “ connecting canal,” and that it can no longer be applied
to “that part of the complemental stipe which crosses the sicula” in Didymo-
graptus, etc., and he suggests the new name of “ crossing canal.”
In his figures he adheres to the old method of drawing them with the apex of the
sicula directed downwards, though he “ by no means under-rates the motives which
may have prevailed upon some authors to figure these fossils in a different position.”
Térnquist recognises the two genera established by Moberg as Isograptus and
Meandrograptus, though he is undecided whether to regard them as sub-genera of
Didymograptus or as distinct genera.
Under the genus Didymograptus, sensu latiori, he describes and figures :
Didymog. suecicus, D. patulus (=D. hirundo), D. extensus, D. constrictus, D. balticus,
D. vacillans, D. filiformis, D. flagellifer, Tullb. MS., and the new species D.
undulatus, D. demissus, /). geometricus, ). Holmi, ). prenuntius, /). validus,
D. Kurcki, and D. Mobergi.
The genus Isograptus mcludes the one species I. gibberulus, and Tornquist adds
a few additional notes on the structure of the initial end.
The genus Mexandrograptus also comprises only one species: M. Schmalenseei ;
the structure of this peculiar form is well brought out by the illustrations.
1901. In 1901 Moberg described and figured a new species of
Moberg, Pterograptus under the name of P. scanicus, and he compares
“ Pterograptus scanicus, it with Holm’s species P. elegans. This species occurs
n. sp.,’ ‘ Geol. Foren.
at Fagelsang associated with a Climacograptus and Didyino-
Forh.,’ bd. 23 Be ae
graptus gemiivus.
PETALOGRAPTUS. 273
Sub-genus Petalograptus, Suess.
1851. Petalolithus, Suess, Ueber Bohmische Graptolithen, p. 20.
1873. Petalograptus, Lapworth, Geol. Mag., vol. x, p. 500.
The sub-genus Petalograptus, as here accepted, includes all those Diplograpti
in which the polypary was more or less tabular in transverse section, and the thecee
were rounded tubes approximating in form and appearance to those of Phyllo-
graptus. Within these limits, the outline of the polypary varies from foliform
(Petalog. folium) to wedge-shaped (Cephalog. cometa).
It is found convenient to refer to the special group or section constituted by
the more wedge-like forms under Hopkinson’s title of Cephalograptus, and to the
collective group constituted by all the other forms of the sub-genus under the
title of Petalograptus proper.
The appearances presented by the thecz in this sub-genus naturally vary
with the general outline of the tabular polyparies. In the more leaf-like forms
belonging to Petalograptus proper, the axis of the theca is curved and directed
outward, so that the apertural edge, though straight and normal, appears concave
and lies obliquely with respect to the general ventral margin of the polypary.
In the more wedge-like forms grouped under Cephalograptus the axis of the theca
is straight and directed upward, so that the flattened-out apertural edge is straight
and practically horizontal.
The mode of development of the initial parts of the polypary is the same as
that characteristic of the Diplograptide in general. But in the group Cephalo-
graptus we find a special modification, which consists in the postponement of the
growth of th. 1? from th. 1! until after the latter has grown up to, or beyond,
the apex of the sicula, and the sicula itself is thus left entirely free on one side,
in the unprotected manner of that in the familes of the Dimorphograptide and
the Monograptide. The Cephalograpti are, however, none the less clearly true
Diplograptide ; for their polypary is biserial throughout, whereas in the
Dimorphograptide the polypary is uniserial in its earlier portion and _ biserial
in its later portion, and in the Monograptide the polypary is uniserial from its
commencement.
Group I. Petalograptus (proper).
Petalograpti in which the polypary is foliiform; proximal end somewhat pro-
tracted, never rounded. Sicula embedded, completely visible only in the obverse
aspect of the polypary. Septum complete or partial. Thece of various lengths,
axis curved, apertural margins concave and oblique in compressed examples.
36
bo
a |
Petalograptus palmeus s.s. (Barrande).
1850.
1851.
pl. viii, figs. 1, 2, 4.
1852.
1853.
8—10.
1876-1880.
1880-1881.
26—28.
1887.
1890.
figs. 39, 41—48.
1898.
p- 9, figs. 29—35.
1897.
1897.
BRITISH
Diplograptus palmeus, Geinitz, Die Graptolithen, p. 21, pl. i, figs. 5
GRAPTOLITES.
Plate XXXII, figs. 1 a—d.
Graptolithus palmeus, Barrande, Grapt. de Bohéme, p. 59, pl. iui, figs. 1—7.
Petalolithus palmeus and parallelo-costatus, Suess, Ueber Bohmische Graptolithen, pp. 20, 21,
19;
Diplograptus palmeus, Richter, Zeitsch. d. deutsch. geol. Gesellsch., vol. v, p. 455, pl. xu, figs.
Diplograptus palmeus, Zittel, Traité de Paleont., vol. i, p. 305, fig. 214 d, e.
Diplograptus palmeus, Linnarsson, Geol. Foren. Forhandl., vol. v, p. 522, pl. xxiii, figs.
Diplograptus palmeus, Tornquist, Geol. Foren. Forhandl., vol. ix, pp. 478—481.
Diplograptus palmeus, Geinitz, Graptoliten des k. mineralog. Mus. Dresden, p. 26, pl. A,
Diplograptus palmeus, Tornquist, Structure of Some Diprionide, Acta Univ. Lund., vol. xxix,
Petalograptus palmeus s.s., Elles, Quart. Journ. Geol. Soe., vol. liu, p. 193, pl. xiv, figs. 1—4.
Diplograptus palmeus, 'Tornquist, Diplog. and Heteroprionide of Scanian Rastrites Beds,
Acta Reg. Soc. Physiog. Lund., vol. viii, p. 10, pl. i, figs. 25, 26.
Polypary from 1
3 cm. in length, widening at once to a breadth of 2°5—3 mm.,
and this bemg maintained the polypary has sub-parallel sides, but is rounded
off distally. Thecze twelve to fourteen in 10 mm., alternate, with an average
length of 2mm., three times as long as wide, overlapping two thirds of their
length; apertural margins concave, oblique.
= <
Description.—The sicula has usually a length of about 2 mm., and extends up
»
to the base of th. 37;
Fias. 188 a and b.—Petalograptus
palmeus (Barr).
|
7
a “Y
y 9)
a b
a. Complete specimen, reverse aspect,
but showing sicula. Nat. size.
Zelkovice, Bohemia. Figured, Elles,
Quart. Journ. Geol. Soc., liii, pl. xiv,
fig. 1. Coll. Brit. Museum (Nat.
Hist.).
b. Reverse aspect of young specimen,
showing sicula pressed through.
Dobb’s Linn, Birkhill Shales. Coll.
Geol. Survey of Scotland, Edin-
burgh,
it is therefore longer relatively to the thece than that of
Petalog. folium. In the Gala-Tarannon examples the
virgella seems to have been particularly stout and
strong, but in the examples occurring at lower
horizons this spine is either wanting altogether, or
is only represented by a short fragment.
Th. 1' originates close to the aperture of the
sicula, and grows outward and upward at once, and
its axial line makes a very decided curve; th. 1?
erows in a manner very similar to that of Petalog.
folium except that its curvature is greater and is
developed earlier than in that species, so that the
sicula is not free for so large a fraction of its length
on the right side. In the obverse aspect of the poly-
pary the sicula is apparently free for about one
quarter of its length on the right side, but im the
reverse aspect the aperture is seen to the left only, the remainder being concealed
PETALOGRAPTUS. 2795
by the growth of th. 1° and the subsequent thecal bases. Th. 1* here runs along
the side of the sicula for a short distance before curving outward.
The first two thecz have each a length of rather less than 2 mm., and are
equally curved, so that the proximal end of the polypary has a symmetrical
appearance and is characteristically short and blunt. The thecee developed
subsequently are rather less curved. The angle of inclination of the thecx is
9ro
3
approximately constant in the narrower forms at 35°, but in the wider polyparies
the angle becomes less towards the distal end, though it is never lower than 20°.
A complete septum is apparently present.
The virgula is very conspicuous as a general rule; it 1s usually prolonged
distally, and the virgular tube has often the appearance of a vesicle.
Affinities—P. palmeus has often been confused with Petalog. folium, but it may
be readily distinguished by :—(1) the relative length and width of the polypary
as a whole; (2) the short and abruptly terminated character of the proximal end ;
(3) the length of the sicula relatively to that of the thece; (4) the relative
length and breadth of the thecz themselves.
Remarks.—In the classification of the Diplograptide (p. 221) we followed the
plan usually adopted by previous authors (Lapw. 1873), and regarded Petalog.
folium as the type of the sub-genus. But in reality Petalog. palmeus was the form
to which Suess first applied the title Petalolithus, and must therefore be taken as
the type.
Horizon and Localities.—Birkhill-Gala (zone of Monog. gregarius to zone of
M. turriculatus).
S. Scotland: Dobb’s Linn; Belcraig Burn; Garple Linn; Sundhope-on-
Yarrow, ete. Lake District: Skeloill; Browgill; Pull Beck; Kentmere; Ashgill ;
Mealy Gill. Wales: Conway; Llanystwmdwy, near Criccieth. Ireland: Coalpit
Bay, Donaghadee.
Associates, etc.—P. palmeus is of common occurrence in all the zones between
that of M. gregarius and that of M. turriculatus inclusive. The species with
which it is most commonly associated are Monog. gregarius, M. fimbriatus, M.
triangulatus, M. Sedgwicki, Glyptog. serratus, G. tamariscus, and Climacog. Hughest
in the Birkhill Shales, and Monog. Becki and M. turriculatus in the Gala-Tarannon
beds.
Oollections—British Museum (Natural History), Sedgwick Museum, Lapworth,
Fearnsides, and the Authors, ete.
Var. latus, Barrande. Plate XXXII, figs. 2 a—f.
1850. traptolithus palmeus var. latus, Barrande, Grapt. de Bohéme, p. 61, pl. i, figs. 3—6.
1897. Petalograptus palmeus var. latus, Elles, Quart. Journ. Geol. Soec., vol. liu, p. 195, pl. xiv,
fies. =e
BRITISH GRAPTOLITES.
In addition to the typical form, P. palmeus, there occurs in the Middle
Birkhill Shales a variety which differs in (1) its greater width; (2) the greater
number of thecx in the same unit of length; (3) the steeper inclination of the
thecx and their greater curvature.
The polypary is commonly shorter than in Petalog. palmeus s.s.; 1b is usually
Fras. 189 a—c.—Petalograptus palmeus,
var. latws, Barr.
a, Obverse aspect, showing sicula. Long
Linn, Dobb’s Linn; Birkhill Shales
(zone of M. gregarius). Coll. Elles.
b. Reverse aspect, showing virgella.
Ibid.
c. Transverse section, showing septum,
ete. Skelgill, Skelgill Shales.
Figured, Elles, Quart. Journ. Geol.
Soe., liii, pl. xiv, fig. 14 (as var. ovato-
elongatus).
about 1:3 cm. in length. The maximum width of
4,
distal extremity, which is broadly truncate, but
5 mm. is attained at once and maintained to the
occasionally rounded.
The thece earliest developed are more curved
than those of the typical form and are rather
longer; the other thecee have an average length of
fully 2 mm., and are three times as long as wide.
The thece in general average fourteen to sixteen
in 10mm. At the proximal end they are inclined
at 45°, but in the more mature parts of the poly-
pary curve very distinctly in an outward direction,
and the angle of inclination decreases uniformly
from the proximal up to the distal end, where it is
about 20°.
Horizon and Localities. —Birkhill Shales (Middle).
S. Scotland: Dobb’s Linn; Garple Linn; and
wherever the zone of Monog. gregarius is typically
developed. Lake District: Skelgill. Ireland: Coalpit Bay, Donaghadee ; Mullagh-
nabuoyah, Pomeroy. Wales: Pary’s Mountain, Anglesea.
Associates, etc.—Var. latus occurs in abundance in certain beds of the Birkhill
Shales; it makes its first appearance about the middle of the zone of Monog.
gregarius and is most abundant throughout the middle and upper parts of that
zone. It never ranges up into the Gala Series, so far as we are aware. It is
commonly associated with Monog. gregarius, M. convolutus, M. fimbriatus, Glyptog.
tamariscus, ete.
Collections.—British Museum (Natural History), Sedgwick Museum, Lapworth,
and the Authors.
Var. tenuis, Barrande. Plate XXXII, figs. 3 a—d.
1850. Graptolithus palmeus var. tenuis, Barrande, Grapt. de Bohéme, p. 61, pl. iii, figs. 1 and 2.
1897. Petalograptus palmeus var. tenwis, Elles, Quart. Journ. Geol. Soc., vol. li, p. 196, pl. xiv,
simedse, YY, MO)
In addition to the wide variety of Petalog. palmeus last mentioned, there is a
second variety which differs from the typical form—(1) in its extreme narrowness ;
PETALOGRAPTUS. 207
»?
(2) in the smaller number of thecze in the same unit of length; (3) im the relative
proportions of the thecz and in the general absence of curvature of their walls.
The polypary is usually small, but may be as much as 1°3.cm. in length; it has
an average uniform breadth of 15 mm. The thece
Fia. 190.—Petalograptus palmeus, var.
fini OBare: number twelve in 10 mm., and are relatively shorter
than in other forms. They are about 1 mm. in
an leneth, twice as long as broad, and overlap one half
are their length. The earlier thecz have shghtly curved
Wy, walls, but those subsequently developed are practi-
Ah cally straight. ‘The angle of inclination is uniformly
W/ about 35°, and the apertural margins are concave
and oblique.
Complete specimen, showing sicula and
well-marked growth-lines, obverse
aspect. Enlargement of Pl: XXXII,
fie. 3c.
A septum is present, but apparently is only
partial. The virgula may be distally prolonged. The
sicula is somewhat smaller than in the typical form.
Horizon and Localities.—Upper Birkhill and Lower Gala.
S. Scotland: Dobb’s Linn; Beleraig Burn. Lake District : Skelgill; Pull Beck.
Wales: Conway; Llanystwmdwy, near Criccieth; R. Twymyn, Llanbrynmair ;
T'arannon River, etc.
Associates, ete—Var. tenuis has much the same range as the typical form ;
it extends from the top of the zone of Monog. gregarius to that of the zone of
M. turriculatus at the base of the Gala beds. It is never a very common fossil.
In general it is found associated with Monog. convolutus and M. gregarius, in the
Birkhill Shales; and with M. turriculatus, M. ewiquus, M. runcinatus and M. pandus
in the Gala-Tarannon beds.
Collections.—Sedgwick Museum, Marr, Lapworth, and the Authors.
Var. ovato-elongatus, Kurck. Plate XXXII, figs. 4 a—d.
1850. Graptolithus palmeus, Barrande, Grapt. de Boheme, pl. 11, fig. 7.
1851. Petalolithus palmeus, Suess, Ueber Boéhmische Graptolithen, pl. viii, fig. 1.
1868. Diplograptus palmeus, Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, p. 528, and pl. xix, figs.
2, 3.
1876. Diplograptus palmeus, Lapworth, Cat. West. Scott. Foss., pl. i, fig. 27.
1881. Cephalograptus ovato-elongatus, Kurck, Nagra Nya Graptolitarter frin Skane, Geol. Foren.
Forhandl., vol. vi, p. 308, pl. xiv, fig. 10.
1890. Diplograptus ovato-elongatus, Geinitz, Graptoliten des k. mineralog. Mus. Dresden, pl. a,
fig. 40.
1897. Petalograptus palmeus var. ovato-elongatus, Elles, Quart. Journ. Geol. Soc., vol. lin, p. 197,
pl. xiv, figs. 11-14.
A third variety, var. ovato-elongatus, may in its mature form be yery readily
BRITISH GRAPTOLITES.
recognised by its characteristic ovato-elongate shape. When young it is practically
impossible to distinguish it from P. palieus var. latus.
-
b
It varies from 1—2°5 cm. in length; and also
Fias. 191 a—e.—Petalograptus palmeus,
var. ovato-elongatus, Kurek.
within certain limits in the relative extent of the
“ovate” and the ‘ elongate” parts. The maximum
width of 4—5 mm. is reached practically at once,
and may be maintained for a well-marked distance
if the ovate part is long. A diminution in width
always takes place, sometimes gradually, at others
somewhat abruptly, and this decreased width is then
maintained to the distal extremity of the polypary ;
the part thus diminished in breadth constitutes the
elongate portion of the polypary.
c In the ovate part the thece have a length of
a, Obverse aspect, in relief, showing
sicula. Skelgill, Skelgill Shales.
Figured, Elles, Quart. Journ. Geol.
Soe., liii, pl. xiv, fig. 12. Coll. Elles.
b. Young complete specimen (probably
referable to this variety), showing
almost circular form; reverse as-
2°5 mm., and are about four times as long as wide,
but their dimensions are less than this in the elongate
part. The thecz are widest at their apertures. In
pect.
c. Transverse section, showing septum
and virgula, ete. Skelgill, Skelgill
Shales. Figured, Elles, Quart. Journ.
the ovate part they are inclined at 45°, but the
angle diminishes to 20° in the elongate part.
The septum does not seem to be complete till
Geol. Soe., liii, pl. xiv, fig. 8 (as var. ;
latus). Coll, Elles. four pairs of thecze have been developed.
Horizon and Localities —Birkhill-Gala.
S. Scotland : Dobb’s Linn; Garple Linn, ete. Lake District : Skelgill, Mealy
Gall.
Associates, etc.—Var. ovato-elongatus 1s a fairly abundant fossil in the upper
part of the Birkhill Shales.
survives into the Lower Gala.
Wales : Conway.
It appears early in the zone of Monog. gregarius, and
It is commonly associated with the typical form,
var. latus, Monog. gregarius, M. couvolutus, and Glyptog. tamariscus.
Collections.—Geological Survey of England and Wales, Sedgwick Museum,
Marr, Lapworth, and the Authors.
Petalograptus cfr. ovatus (Barr.). Plate XXXII, fig. 6.
1850. Graptolithus ovatus, Barrande, Grapt. de Bohéme, 1, p. 63, pl. 11, figs. 8, 9.
1851 Petalolithus ovatus, Suess, Ueber Bohmische Graptolithen, p. 21, pl. vin, fig. 3.
1852. Diplograpsus ovatus, Geinitz, Die Graptolithen, p. 20, pl. i, figs. 3 and 4.
1890. Diplograptus ovatus, Geinitz, Graptolithen des k. mineralog. Mus. Dresden, p. 25, pl. 4,
fie. 37.
1897. Petalograptus ovatus, Elles, Quart. Journ. Geol. Soc., vol. liii, p. 199, pl. xiv, figs. 15, 16.
Polypary very small, ovate, nearly as wide as long. Sicula large. Thece at
rate of twenty-eight in 10 mm., very long and narrow, with slight curva-
PETALOGRAPTUS. 279
ture, in contact for nearly the whole of their length; apertural margm
shehtly concave, everted in compressed specimens.
Description.—The well-known Bohemian species—Petalog. ovatus—is but
doubtfully represented in the British Isles. The specimen here figured (PI.
ARO ee ee XXXII, fig. 6) and provisionally referred to this
(Barr.). form comes from Skelgill in the Lake district. It
possesses the almost circular outline so character-
istic of the Bohemian species, but differs in the
Typical specimen of P. ovatus, natural Character of the proximal end, the earlier thecz
Se Wick Mente nema Cll ‘being longer, more curved and less horizontal than
Sedgwick Museum. to) tay
is usual.
The sicula is relatively long, measuring 1:5 mm. in length and reaching to the
level of the third thecal pair.
The thece are very closely set, in the proportion of twenty-eight in 10 mm.,
but there are generally only seven or eight in the entire length of the polypary.
We figure here for comparison a typical specimen from Gelkovice, Bohemia.
Affinities —Detalog. ovatus is readily separable from all other Petalograpti by
its nearly circular form, the closely-set thecx, and their horizontal direction of
erowth.
Horizon and Localities. —Gala-Tarannon Shales.
Lake District: Skelgill. N. Wales: Conway.
Associates, etc.—Very few specimens of Petalog. cfr. ovatus are known from
Britain; the best specimen comes from the Broweill beds of Skelgill,and was found by
Mr. W. A. Brend associated with Monog. Marri. It is now in the Sedgwick Museum.
Collections.—Sedegwick Museum, and the Authors.
Petalograptus minor, Elles. Plate XXXII, figs. 5 a—e.
1893. Diplograptus palmeus, Tornquist, Structure of some Diprionide, Acta Univ. Lund., vol.
xxx, pl. i, figs. 29—31.
1897. Petulograptus minor, Elles, Quart. Journ. Geol. Soe., vol. liii, p. 201, pl. xiv, figs. 17—21.
Polypary always small, rarely exceeding 1 em. in length, concavo-convex in
section, the convexity being on the reverse aspect ; generally oblong in out-
line, with narrow rounded distal end; widening gradually from origin, and
attaining maximum width of about 3 mm. at a point midway between the
proximal and distal extremities. Thece twelve in 10 mm., alternate,
having an average length of 2 mm., four and a half times as long as wide ;
inclined at 45°; apertural margins slightly concave in profile view.
Description.—The shape of the outline of the flattened polypary, and its
280 BRITISH GRAPTOLITES.
transverse concavo-convexity in specimens preserved in relief, are both very
characteristic. In general there is a diminution in breadth of outline as soon
as the polypary has attaimed its maximum width,
Frias. 193 a and b.—Petalograptus minor, 4
Elles. but this is not invariably the case. Occasionally,
SB Bit as a result of the extreme convexity of the reverse
a7 CNA aspect, the distal end in that view has a pointed
ie WV appearance, but this is unusual.
The sicula is slender and very long, being
a. Obverse aspect, showing apertural usually 3 mm. in length; its apex usually lies on a
part of sicula. Long Linn, Dobb’s : 1 :
Linn; Birkhill Shales (zone of M. level with the aperture of th. 41, but it tapers so
gregarius). Coll. Elles. 0 : : 7 6 :
b, Reverse aspect, showing apical part finely in an upward direction that in many speci-
eae aia mens it is hard to determine where the sicula ends
and the virgula begins. UOLZLIUIUIVUIGO “fF
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SOGRAPTUS.
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ce ror mp reduced to a mere film and is possibly punctate.
} Rel m : ;
Sd Pia ay The thecz assume very different appearances
a a4 en ates (Lapworth, 1880, loc. cit.). In the obverse
au pies appearances Rae ae aspect they may appear quite normal, with the
Ge eee Ga ee peaaes short free edge and everted aperture showing
Fr Oe Curae EN Clee clearly (Fig. 200 7), but if much compressed
the free edge seems to be squeezed out into a knob (Fig. 200d) or occasionally
may even be drawn out to appear submucronate (ibid.); while in the reverse
9
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298 BRITISH GRAPTOLITES.
aspect the theez either show as mere crenulations in the ventral margin or seem
almost obliterated as the result of compression (Pl. XXXII, fig. 12 0). It is
highly characteristic of this species that when preserved in relief the two ventral
sides are never alike in appearance (Figs. 200 d—;). In scalariform views
(Figs. 200 f and 2) the large size of the apertures compared with that of the free
outer edge of the theca is very obvious. These details can only be made out in
specimens in low relief, and it is therefore not surprising to find that the
different views of this form have been regarded as distinct species by earlier
authors; such forms as Hall’s Graptolithus marcidus and Hopkinson’s Diplog.
Etheridgii are now generally admitted (comp. Ruedemann) to be only differently
presented specimens of Cryptog. tricornis.
Affinities. —Cryptog. tricormis can be readily identified. It is a far more
slender and delicate form than any other Cryptograptus yet recognised.
Horizon and Localities —Upper Arenig, Llandeilo - Bala, Glenkiln - Hartfell
(especially in zones of Dicellog. patulosus and Climacog. Wilsont).
S. Scotland: Hartfell; Dobb’s Linn; Tottleham’s Burn, Castle Douglas;
Berrybush Burn, St. Mary’s; Birnock, Abington; Laggan Gill, Girvan, etc.
Wales: Nant yr Orlof, Penmorfa; Arenig; Tiddyndicwm; Abereiddy Bay ;
Porthhayog, Ramsey Island; Blaen-y-delyn Quarry, near Fishguard. Ireland :
Coalpit Bay, Donaghadee; Ballygrot, Co. Down; Craigavad, Co. Down; Derry-
naclough, Connemara.
Associates, ete.—C. tricornis 1s an abundant fossil in the Upper Llandeilo and
Lower Bala rocks and their equivalents, but it is very rarely well preserved
owing to the delicate nature of its test. The best specimens are those from
Laggan Gill in the Girvan district, where it occurs in low relief in the
transition zone between the Balclatchie and Ardwell Groups; these forms are
invariably small. In the beds of Arenig age it occurs associated with Didymog.
bifidus and also with D. evtensus. In the Lower Llandeilo it is found at Abereiddy
Bay in tolerable abundance associated with Didymog. Murehisont; 1m the higher
Llandeilo (Glenkiln) beds it occurs in profusion, associated with Dicranog. ziczac,
Dicellog. patulosus, and Climacog. peltifer ; itis also abundant in the overlying basal
zone (Olimacog. Wilsont) of the Hartfell Shales (Bala), associated with OClimacog.
Scharenbergi, and Dicranog. Nicholsoni, and has also been found in the succeeding
zone of Dicranog. Clingani.
Collections.—Geological Survey of Scotland, Sedgwick Museum, H. B. Muff and
R. G. Carruthers, Lapworth, and the Authors.
CRYPTOGRAPTUS. 299
Var. Schaferi, Lapworth. Plate XXXII, figs. 13 a—c.
1880. Cryptograptus tricornis var. Schiferi, Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, pl. v,
figs. 28a and b.
A well-marked variety of Cryptog. tricornis is fairly common in the Llandeilo
beds of certain localities. It was figured in 1880 by Lapworth as var. Schdferi,
but has not hitherto been described. This variety
Fras. 201 a and b.—Cryptograptus tri- ig somewhat wider than the typical form in the
cornis, var. Schdferi, Lapw.
obverse aspect (perhaps therefore the polypary
was somewhat less concayvo-convex), and the ex-
fi) A tremely short free edges of the thecz are produced
ry 4 \ into distinctly mucronate extensions, but there are
no conspicuous basal spines.
a b
The downward direction of growth of th. 1! is
a. Young stage, showing sicula and th. : . : :
1, reverse aspect. On same sla Very marked in this variety, and it would appear
as Pl. XXXII, fig. 13 c. i or f 2g = > zs
b. Somewhat older stage showing sicula (Fig. 201 b) that th. 1° also grew downward. It
and th. 1!and th. 1°; obverseaspect. ; = as > “BRD =
Guba nisielan ae a 200, is not known at what point the upward direction
of growth commences.
Horizon and Localities.—Llandeilo, Glenkiln Shales.
Wales: Llandeilo; Abereiddy Bay; behind Pencerrig House, near Builth;
Gwern-y-fed-fach, Builth; Llandrindod. S. Scotland: Tottleham’s Burn, Urr
Water; Kirriemore Burn, Minnoch Water.
Associates, ete.—Var. Schdferi occurs in fair abundance in the Builth District at
various localities north of Llandrindod Wells associated with Dicellog. seatans,
Nemag. pertenuis, and Thysanog. retusus.
Collections —Sedgwick Museum, Lapworth, and the Authors.
Cryptograptus Hopkinsoni (Nicholson). Plate XXXII, figs. 15 a and b.
1869. Diplograptus Hopkinsoni, Nicholson, Ann. Mag. Nat. Hist. [4], vol. iv, p. 234, pl. xi, fig. 7.
1898. Cryptograptus Hopkinsoni, Elles, Quart. Journ. Geol. Soc., vol. liv, p. 520.
Polypary robust, 1—2 em. in length, with average uniform breadth of 2 mm.,
base adorned with two long curved spines. Thecee ten in 10 mm., of
general Cryptograptus type but with free edges of all thecz provided
with spines.
Description—The polypary mm Cryptog. Hopkinsoni is relatively wide, apart
from the spines which give it still greater apparent breadth; it 1s commonly
small, not exceeding 2 cm. in length.
300 BRITISH GRAPTOLITES.
The thecz are of the same general type as those of Cryptog. tricornis, but a
spine grows out from the lower end of the short free edge of each theca, and is
often so stout that when compressed it seems as if the denticle itself were drawn
out into a spine; in less compressed examples, however, the true origin is clear.
These thecal spines may have a length of fully 2 mm., while those belonging to
th. 1' and th. 1° (the basal spmes) are about 5 mm. long and are gracefully curved.
The test appears to be attenuate, but to be thicker than in C. tricoriis.
Affinities—C. Hopkinsoni differs from Cryptog. tricorms in the greater length
of the curved basal spines, and in the fact that all the thecz: have ventral spines ;
the polypary also is wider in proportion to its length.
Horizon and Localities—Middle and Upper Skiddaw Slates.
Lake District: Outerside; Bannerdale Fell; Glenderamakin Valley.
Associates, ete.—Cryptog. Hopkinsoni has, up to the present, only been recorded
from the Skiddaw Series; where it occurs associated with Tetrag. quadribrachiatus
in the Middle Skiddaw Slates and with Didymog. indentus in the Upper Skiddaw
Slates. It is not an abundant fossil. The type specimen is in the British
Museum Collection.
Collections.—British Museum (Nat. Hist.) and Sedgwick Museum.
Cryptograptus (?) antennarius (Hall). Plate XXXII, figs. 14 a—e.
1865. Climacograptus antennarius, Hall, Grapt. Quebee Group, p. 112, pl. xviii, figs. 11—13.
1868. Diplograpsus antennarius, Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, p. 139.
1870. — Climacograptus antennarius, Nicholson, Ann. Mag. Nat. Hist. [4], vol. vi, p. 382, fig. 6.
1898. Cryptograptus (?) antennarius, Elles, Quart. Journ. Geol. Soe., vol. liv, p. 519, fig. 31.
1904. Climacograptus (?) antennarius, Ruedemann, Grapt. New York, pt. i, p. 721, pl. xvi, figs. 21—26.
Polypary robust, 1°5—2°5 em. in length, with an average uniform breadth of
2mm. Virgella small but usually conspicuous; basal spines long, stiff.
Thecs, ten to eleven in 10 mm., unknown except as sub-scalariform
impressions or as crenulations of the ventral margin.
Description.—All the British specimens of OC. antennarius come from the
Skiddaw Slates, and are badly preserved, so that the thecz are never well seen.
The general form of the polypary, the sub-horizontal position of the basal spines,
and the concealed thece all point in the direction of Cryptograptus, to which genus
we believe the form belongs, though it may be a Climacograptus.
The long basal spines form the most conspicuous characteristic of this species ;
as a rule, two only are seen, but not infrequently three are present, and it seems
almost certain that there were four, th. 1’ and th. 1? each being furnished with
a pair. These spines are all stiff, approximately rigid, and fairly stout; they may
measure 8°7 mm. in length.
TRIGONOGRAPTUS. 301
In one specimen spines similar to the basal ones are seen proceeding from
a thecal pair situated higher up the polypary.
Affinities. —C. antennarius may be readily separated from all other Cryptograpti
by the long, stiff spines at its proximal end; these are much longer and stouter
than those found in Oryptog. tricornis, and the whole character of the polypary is
more robust.
Horizon and Localities —Upper Skiddaw Slates.
Lake District: Outerside; Mungrisedale; Glenderamakin Valley ; Mosedale
Beck, near Troutbeck ; Bannerdale Fell.
Associates, etc.—C. antennarius is a fairly common fossil in the Upper Skiddaw
Slates, associated with Didymog. indentus. It is, however, invariably poorly
preserved.
Collections.—British Museum (Natural History), Sedgwick Museum, Keswick
Museum.
Genus TRIGONOGRAPTUS, Nicholson.
1869. Trigonograpsus, Nicholson, Ann. Mag. Nat. Hist. [4], vol. iv, p. 232.
Polypary \ilaterally symmetrical, biserial throughout, transverse section
concayo-convex or trigonal, ventral edges having the appearance of bemg
even and continuous.
Thece resembling those of Phyllograptus and Ietiolites.
Test thick, membranous, with transverse growth-lines.
The genus Trigonograptus was founded by Nicholson to include certain
Graptolites found in the Skiddaw Slates of the Lake District. The thece are
generally well marked, and appear to be sub-rectangular tubes expanding towards
their apertures, and overlapping for the whole of their extent. hey not only
recall those of Phyllograptus but also those of Retiolites.
The transverse section of the polypary was probably strongly concavo-convex
or even trigonal, and the appearance of the thecz varies very much in different
views.
Only one species and a variety are known with certainty in the British Isles—
Trigonograptus ensiformis and var. lanceolatus.
Note.—The first recognised species of this genus—Hall’s Graptolithus ensi-
formis—was regarded by its discoverer as belonging to Mettolites (Barrande) or an
allied genus (Hall, ‘ Grapt. of Quebec Group,’ p. 114). This opinion, which is in
harmony with certain similarities in outward form and appearance, has naturally
led to its being generally assigned to the family of the Retiolitidee (Lapw., ‘ Geol.
Mag.,’ 1878, Table, p. 555, and others). Although it must be admitted that our
302 BRITISH GRAPTOLITES.
knowledge of the structure of the polypary in this genus is still very imperfect,
such British examples as have come to hand lead us to infer that the alliances of
the genus are rather with the Phyllograptide and Diplograptidee, and we place it
here provisionally in the latter family on account of its biserial character.
Trigonograptus ensiformis (Hall). Plate XX XV, figs. 1 a—c.
1865. Retiolites ensiformis, Hall, Grapt. of Quebec Group, Geol. Survey of Canada, dec. 2, p. 114,
pl. xiv, figs. 1—5.
1890. ‘Trigonograptus ensiformis, H. O. Nicholson, Geol. Mag., dec. 3, vol. vii, p. 340, figs. 1, 2.
1898. Trigonograptus ensiformis, Elles, Quart. Journ. Geol. Soc., vol. liv, p. 523, fig. 34.
1904. Trigonograptus ensiformis, Ruedemann, Grapt. New York, vol. i, p. 727, pl. xvii, figs. 1—9.
Polypary 3—5 cm. or more in length, with an average uniform width of
about 5 cm. attained by rapid widening from proximal end, diminishing
somewhat distally. Sicula doubtful. Thecz eleven to nine in 10 mm.,
SP OIE ee apparently inclined at about 50°, in con-
ensiformis (Hall). tact throughout their length, their aper-
tural edges usually forming collectively
an unbroken line constituting the ventral
margin of the polypary. ‘Test thick,
membranous, marked by growth-lines.
Description.—TVhe dimensions of the majo-
rity of our British specimens seem to fall a
little short of those given by Hall, and examples
of about 3 cm. in length are of most frequent
occurrence. In other respects, however, our
specimens agree well with the American ones.
In one specimen (Pl. XXXYV, fig. la) a
membranous structure is seen projecting from
the proximal extremity of the polypary. This
may in part represent the sicula.
The thecz present different appearances in
different specimens. In some examples (Fig.
202 a) the walls of the thece are parallel and
a. Proximal end, showing sicula (?) and mem- :
pranous structure. Enlargement of part continuous from the ventral edge of the polypary
of Pl. XXXV, fig. la. : : A
b. Distal theee, showing growth-lines. Hn- 10 its central line; im others (202 6) the walls
largement of part of Pl. XXXV, fig. 1b. i hl te : :
A Did tieee on widelapeamion “Roadside appear Lo be curved and there is an oblique ridge
N. end of Doolough, Co. Mayo; Arenig.
Cell. Maat ana! Casnutliors. running down the centre of each theca. In one
Trish specimen (202 ¢) the polypary appears at
first sight to present a totally different aspect on the two sides of the central line.
On the one side the theese resemble those of one of the four stipes of a Phyllo-
TRIGONOGRAPTUS. 303
graptus when shown in profile view, but the edges of the aperture are straight or
rounded instead of concave; on the other side the thecal apertures, or their
impressions, are presented in scalariform view. These appearances might be
accounted for if the polypary were composed of two stipes disposed at right angles
to each other, somewhat like a Phyllograptus with only two of its adjacent stipes
developed. Growth-lmes appear occasionally on the theca, but there is no visible
reticulation of the test, which in British specimens appears to be membranous and
continuous.
Affimties.—T. ensiformis may be readily separated from its variety lanceolatus
by its general shape.
Horizon and Localities—Arenig, Upper Skiddaw Slates (Hllergill Beds).
Lake District: Mosedale Beck, near Troutbeck; Hlergill, near Millburn.
Ireland: Roadside, N. end of Doolough, Co. Mayo. S. Wales: Pont-y-feni Quarry,
3 miles W. of St. Clears.
Associates, etc.—The associates of J’. ensiformis in the Skiddaw Slates are
unknown; but it has been found in Co. Mayo associated with Loganog. Logant,
Phyllog. angustifolius, Tetrag. quadribrachiatus, and Glossog. acanthus ; and by the
officers of the Geological Survey in 8. Wales with Didymog. cfr. wriformis.
Collections—Nicholson, Geological Survey of Hngland and Wales, Sedg-
wick Museum, Muff and Carruthers.
Var. lanceolatus (Nicholson). Plate XXXV, fig. 2.
1869. Trigonograpsus lanceolatus, Nicholson, Ann. Mag. Nat. Hist. [4], vol. iv, p. 232, pl. xi, fig. 6.
A variety of Tvigonog. ensiformis is also found in the Skiddaw Slates and
Fie. 203.—Trigonograptus ensiformis, a8 been described by Nicholson. It differs chiefly
Be eect rene h Nach) from the typical species in the rapidity with which
ee it widens in the proximal region, and in haying a
oO NGAT distinct zigzag septal groove or thickening. The
es se | only British specimen known to us shews no details
\ aS #/ as to the structure of the thecx, but there are
Ie | fourteen in 10 mm.
Distal part showing position of theese Horizon and Locality—Upper Skiddaw Slates
and zigzag septal groove; pre-
served as a cast. Enlargement of (Hilergill Beds).
parek Pls ARV Ease: Lake District: Hllergill, Millburn.
Associates, ete—Unknown.
Collection.—British Museum (Natural History).
304. BRIMSH GRAPTOLITES.
Fanily GLOSSOGRAPTIDA, Lapworth.
1873. Glossograptide, Lapworth, Geol. Mag., vol. x, table 1, p. 555.
1880. Lasiograptide, Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, p. 175.
1880. Lasiograptide or Glossograptide, Lapworth, Ann. Mag. Nat. Hist. [5], vol. vi, p. 188.
Biserial Graptoloidea with straight polyparies; test membranous, continuous,
attenuated, more or less strengthened by lists, ribs, or filaments, which may, im
whole or in part, constitute together a supporting net-like framework or skeleton.
Thece of the general Diplograptid type, provided with spurs, spines, or other
processes, which may be simple, branching, or connected to form an external
lacework of marginal meshes.
A first and most characteristic feature of this family is afforded by the invariable
presence of external processes in the form of spurs, spines, or strong filaments. Some
of these agree in all essentials with those met with in the spme-bearing species of
the Diplograptidee (Orthog. quadrimucronatus, etc.), but others are very different,
and in no other family of the Graptolites are these processes so distinctive or so
varied in their form and peculiarities.
These extraneous processes in the Glossograptide are either medial or marginal
in position ; occurring either along (1) its central longitudinal line (7. ¢. that marked
by the sutural groove in those Diplograptidee which are provided with a septum)
or (2) its ventral edges. As the terms mesial and marginal are pre-occupied,
the two sets of processes are here classed as septal and ventral, these terms being
employed merely as indicative of relative position.
The septal processes, when present, apparently arise at right angles to the axes
of the thece, and form two ranks—one on the obverse and one on the reverse
aspect. In both ranks they appear to be given off from the bases of alternate
thece.
The ventral processes are either apertural or mesial in origin with respect to
each theca, arising either from the angles of the apertural margin or from the
upper angle of the excavation. In both cases they always appear to be paired.
Both septal and ventral processes may, within the limits of the family, take
the form of (1) rigid blind spurs (Fig. 205 ¢), (2) more or less flexuous spines
(Fig. 204), or (3) filamentous and fibrous processes, either simple, branching, or
anastomosing (Fig. 213 ¢). When in the form of simple spurs or spines they
significantly call to mind the proximal spines of the polypary im some of the
Diplograptidee, and, like those, occasionally support between them a membranous
pelta, web, dise, or vesicle (Fig. 212 b). The branching processes are usually more
fibrous in their nature and may support a much larger vesicle or pelta (Fig. 212 a).
GLOSSOGRAPTID.A. 305
The anastomosing processes are somewhat stout at their origin, becoming more
filiform as they extend; and in several species they unite exteriorly with the
corresponding processes above and below, and thus form in combination a more or
less continuous external meshwork or lacework (/acinia) completely surrounding
the theca-bearing portion of the polypary (Figs. 215 a and e).
A second characteristic of the Glossograptide which is intimately related to the
first (compare Ruedemann, ‘Grapt. New York,’ Part 2, pp. 69—87) is afforded by
the distinct slrengthening of the edges and angles of the polypary and thece, and the
simultaneous attenuation of the mtervening parts of the test.
Within the limits of the family of the Diplograptide, as we have seen, there is
an occasional tendency for the test to become somewhat thickened along certain
definite lines. Thus, in Orthog. quadrimucronatus this thickening takes the form
of a well-marked selvage, band, or flange, surrounding the edge of the aperture ;
while in Amplewog. perexcavatus not only is the apertural margin strengthened
in this way, but also the ventral angles of the test around the excavation.
But in the family of the Glossograptide this tendency to local thickening and
strengthening becomes progressively developed and intensified. Not only may
the apertural margins and ventral angles of the thecee become strengthened in this
way, but the strengthening may be continued along the outer line of contact of the
thecal walls across the main body of the polypary, into and even along the median
sutural line itself, the course of which may become marked by a continuous
strengthening as definite as that marking the apertural margins. In all cases the
local strengthening seems to be attained at the expense of the remainder of the
test, which throughout the whole family of the Glossograptide is remarkably thin.
As this progressive differentiation is followed through the various genera
and species, these narrow bands, selvages, or lists become more and more
rounded and cord-like, and may eventually present the appearance—especially in
examples preserved in pyrites—of wire-like fibres, coarse threads, or strong
filaments, which are strikingly contrasted with the attenuated parts of the test
which they support.
Within the limits of the related families of the Glossograptide and the
Retiohtidee occur forms showing almost every gradation between those in which
only a few of the edges and angles are strenethened by lists or filaments, and those
in which all the edges and angles are outlined in this manner.
These lists may be regarded from two distinct points of view—(qa) as related to
the elemental structure or theca, and ())) as related to the compound structure or
polypary.
As respects their relation to the individual theca, they may outline the lp of its
external opening (apertural or oral lists); the sides of that opening (pleural) ; the
angles of the excavation (mesial) ; the lip of its mternal budding orifice (portal
or aboral) ; the outer line of contact with the theea immediately above or below
40
306 BRITISH GRAPTOLITES.
(parietal, Holm); and the line of contact along the sutural groove with the
opposing thece of the alternating series (dorsal lists).
As regards the relations of the lists to the polypary considered as a whole, it
naturally follows that when all the individual thec are outlined as above, the thecal
lists constitute in combination a collective net-like or cage-like framework (clathria,
from Lat. clathii or clathra), which forms, as it were, a skeleton of the complete
polypary. Those thecal lists which then le in the same general longitudinal line
combine in appearance or reality into a single longitudinal list or strand (Wiman)
running from end to end of the polypary, and the thecal lists which lie transverse
to these form connecting cvoss-bars or ledges (Gurley).
Thus the dorsal lists combine into two longitudinal medial or septal strands, one
(which is usually zig-zag) on the obverse, and one (which is usually straight) on
the reverse aspect of the polypary. The pleural and other ventral lists combine into
four longitudinal ventral strands, which are generally somewhat undulating and
irregular. ‘These upright strands are united in pairs by the cross-bars which are
formed by the apertural and parietal lists (somewhat as the sides of a ladder are
united by its rungs, or the sides of a lattice by its cross-bars).
The skeleton or clathria attains its most perfect development in the family of
the Retiolitidee, in the typical species of which—Retiolites Geinitzianus—its essential
elements have been made known to us by the researches, descriptions, and figures
of Tullberg, Térnquist, Holm, and Wiman (see Figs. 220 d—f).
The longitudinal strands enable us conventionally to regard the structural
meshwork of the clathria as divisible into six fields (Wiman), scalars, or lattices :
namely, two ventral lattices, of each of which the sides are the two upright ventral
strands, and the cross-bars (which are normally horizontal) are usually the
apertural lists of the theca; and four parietal lattices, of each of which the
more or less upright sides are formed by one of the septal strands and one
of the ventral strands lying on the same aspect, and the cross-bars (which are
usually inclined) are the parietal lists. In addition to the cross-bars belonging to
these six lattices, the clathria is sometimes provided with two sets of internal
transverse cross-bars or struts, formed of the aboral lists.
Owing to the differences in the original shape of the polypary and thecz, and
the special parts of these which have been strengthened or differentiated as
lists or filaments, there are great variations in the extent of development and in
the details of the apparent skeleton as presented by the several species of Glosso-
graptide and Retiolitide. Some of the so-called strands are often only such in
appearance, being formed of different elements in different parts of their length ;
and the cross-bars of the apparent ventral lattice are not always the same in origin.
The combined appearances presented in compressed specimens of the Glosso-
graptide by (a) the clathria when partially developed, (6) the remainder of the
polypary, and (c) the various external appendages, are always difficult of interpre-
GLOSSOGRAPTUS. 307
tation. Not only do these appearances alter with every change in the amount
or the direction of compression, but owing to the general tenuity of the test the
upper and lower faces of the fossil as presented, are often shown in superposition
in the same view.
As regards the general mode of development of the initial part of the polypary in
the Glossograptid, it resembles in the main that of the Diplograptide.
As respects the systematic position of the Glossoqraptide, the general form of the
polypary and the shape of the thece, both indicate a close relation to the
Diplograptide, but the localisation of the thickening in the test resulting in
the ultimate development of the skeletal frame-work is indicative of a most
intimate relationship with the family of the Retiolitidee, with which it was originally
associated by Lapworth in 1873 (‘Geol. Mag.,’ vol. x, p. 555), to constitute the
section Retioloidea.
Within the limits of the family of the Glossograptide, as at present understood,
there are three divisions, typified respectively by the genera Glossograptus, Lasio-
graptus, and Ietiograptus (Clathrograptus).
In the genera Glossograptus and Retiograptus the thece are of the type of
those of Orthograptus: in the genus Lasiograptus they are usually of the type
of those of Amplexograptus.
Genus GLOSSOGRAPTUS, Hiimons.
1855. Glossograptus, Emmons, American Geology, vol. i, p. 108.
Polypary bilaterally symmetrical, truncato - elliptical in transverse section,
provided with both apertural and septal processes. Apertural processes
simple paired spines ; septal processes in the form of stiff, blind spurs.
Thece of the general type of Orthograptus.
T'est membranous, continuous, attenuated.
The truncato-elliptical transverse section of the polypary is evidenced by its
lesser breadth when seen in the scalariform view, as compared with its breadth in
the bi-profile view, and the still greater width when seen diagonally.
In the general mode of development of the proximal end the Glossograpti
resemble the Diplograptide ; the sicula and earher theca, however, are relatively
more spinose. The downward direction of the earlier spies, combined with the
more or less horizontal growth of th. 1! and th. 1°, give the proximal part of the
polypary an appearance recalling that of the Phyllograpti.
In Glossograptus each theca has at least two apertural spines, though it not
infrequently happens that, owing to the direction in which compression has been
effected, only one is visible. These apertural spines may be stout or slender, but
308 BRITISH GRAPTOLITES.
ee
they are always somewhat stiff m appearance, and are generally arcuate in form
with the convexity upward. The bases of these spines are relatively broad, and
have the appearance of being formed as prolongations of the combined thickened
selvages of the whole of the denticle formed by the apertural and ventral edges of
the theca. In general, these spines are about equal in length to the breadth of the
polypary itself. In the proximal region they are directed downward but gradually
alter their direction, first to a horizontal one in the middle of the polypary, and
eventually to an ascending one towards its distal end.
In addition to the apertural spines, the polypary always appears to possess a
series of septal spines. ‘These originate from the mid-line of the polypary in
a direction at right angles to the direction of the apertural spines, and are con-
sequently best seen in the scalariform view, in which, owing to the direction of
compression, the apertural spines are hidden, or so foreshortened as to be rarely
visible. The septal spines occur both on the obverse and reverse aspect of the
polypary, and in both cases apparently originate at or near the bases of alternate
thece. As a rule they are larger and stiffer than the apertural spines, and usually
take the form of blind spurs with broad bases.
Owing to the presence of these two sets of spines, the appearance of the
polypary varies according to the direction of compression. In the bi-profile
view the apertural spies alone are seen, and may appear to be single or
paired. In the scalariform view the septal spines alone are usually visible, and the
tips of the apertural spines are presented in addition only in rare cases. In the
sub-scalariform view both sets of spines are visible in whole or in part, and
the ventral margins of the polypary have then a most remarkably spinose appearance
throughout.
The thickenings of the angles and edges of the test in this genus are mainly
confined to the apertural and ventral edges of the thecz and the bases of the
septal spurs; but there is occasionally seen a well-marked longitudinal thickening
bordering what appears to be the outer line of the septum on the two aspects,
forming a pair of more or less continuous longitudinal ridges or strands (?) running
parallel with the central line of the polypary.
Four species of Glossograptus and one variety have been recognised in the
British Isles, viz. :
Glossog. cfr. ciliatus.
Glossog. Hincksii.
var. fimbriatus.
Glossog. armatus.
Glossog. acanthus,
GLOSSOGRAPTUS. 309
Glossograptus cfr. ciliatus, Hmmons. Plate XXXII, fig. 1.
1855. Glossograptus ciliatus, Emmons, American Geology, vol. 1, p. 108, pl. i, fig. 25.
1908. tlossograptus ciliatus, Ruedemann (pars), Grapt. New York, pt. 2, p. 379, pl. xxvii,
figs. 1—4,
Polypary broad with parallel margins, from 1—2 cm. or more in length, and
with a maximum breadth of about 4mm. Thece ten in 10 mm., with
long and somewhat delicate spines; apertural margins approximately
horizontal.
Description.—The species here described and figured is the only British one
that appears to us to resemble Emmons’ species, to
Bra. 204— Glossograpius el. cilialus, ich it is here doubtfully referred. All the speci-
Emmons.
mens are small, and probably represent young
on SY forms; the one here figured shows the parallel
— pie y wo margins, broad base, and relatively long and slender
he gaat, = : Bes :
Dyes. gy 2 (ciliate) spines characteristic of the type specimens
a a , ws ;
» bes aa figured by Emmons. In our British examples it
“ee MY se ae S
— Prag ey >> eye ie epee aie te, : i
Bo sg is impossible to distinguish the apertural from the
“SS ax septal spines.
The sicula is partially visible for a length of
eee oat eae ae 8 mm., but its apertural spines are not preserved.
Affinities. —Glossoq. cfr. ciliatus resembles in some
respects Glossog. acanthus, but differs im having sub-parallel margins and longer
and more delicate spines. From Gilossog. Hincksii it appears to be distinguished
by the broader base of the polypary, the more distant thecz, and the characters of
the spines.
Horizon and Locality.—Llandeilo. Wales : Ty-Obry.
Associates, ete.—Glossog. cfr. ciliatus is found in the Llandeilo rocks of Ty-Obry
associated with various Diplograptide.
Collection.— Sedgwick Museum.
Glossograptus Hincksii (Hopkinson). Plate XXXIII, figs. 2 a—.
1872. Diplograptus Hincksii, Hopkinson, Geol. Mag., vol. ix, p. 507, pl. xii, fig. 9.
1876. Glossograptus Hincksii, Lapworth, Cat. West. Scott. Foss., pl. i, fig. 57.
1877. Glossograptus Hincksii, Lapworth, Proc. Belfast Nat. Field Club, p. 134, pl. vi, fig. 24.
Polypary 2—4 cm. in length with rounded base, widening rapidly to a
maximum breadth of 3mm., which is then maintained. Sicula obscure,
apertural spines of sicula and of all proximal thece directed more or less
310
vertically downward.
Virgular tube long and conspicuous,
BRITISH GRAPTOLITES.
Theez sixteen
to ten in 10mm., overlapping about one half their length; apertural
margins straight, or but shghtly everted; apertural spines strong, arcuate,
nearly as long as width of polypary; septal spines straight, spur-like,
ascending.
Description.—The polypary of Glossog. Hincksti varies very much in size ; some
specimens may be as much as 4.cm, in length, but the majority are smaller and do
not exceed 2°5 cm.
These smaller forms rarely reach the maximum breadth, but
all show the subparallel character of the ventral margins.
The characters of the proximal end are obscure; the sicula seems to be at least
1 mm. in length and to havea stout virgella and also an additional apertural spine on
Fras. 205 a—e.—Glossograptus Hincksii (Hopk.).
Dh th
ey, |), Pe : \
—< ™ ee = a oa
as ma Ean” ™ ef
Re Cy, = ™ ip
Se 2 4 ‘ =~ ‘{' os ~ a
Si wf Niwa is
BEA. A rs
Be eee,
a b c
the other side of its aperture, while
the apertural portion hes wholly
outside the polypary. The position
on the sicula where th. 1' originates
has not been determined, but the
erowth of th. 1'1is mainly in a hori-
zontal direction, the thecee bending
upward eventually close to the
aperture ; the same is also the case
with th, 1,
from these thecze both from the
Spines are given off
a, Proximal end, showing both thecal and septal spines. En-
largement of part of Pl. XX XIII, fig. 2/f.
b. Proximal end, showing lone curved apertural spines. En-
largement of part of Pl. XX XIII, fig. 2 a.
c. Young specimen, probably referable to this form, with
conspicuous septal spine. Dobb’s Linn, Glenkiln Shales.
Coll. Lapworth.
aperture and also from the point
(mesial) at which change of growth
takes place, and they are directed
mainly downward. The second pair of thecee, th. 2' and th. 2°, and all succeeding
thecx grow upward and outward in the usual Diplograptid manner. The apertural
spines become gradually more and more ascending in position, until in the
distal part of the polypary they are directed upward. These spines are
always strong, and are arcuate in form; in the proximal region they do not
exceed 1 mm. in length, but in the median region of the polypary, where they
are practically horizontal, they may be nearly 3 mm. long. The septal spines are
straighter and spur-like, and appear to have an ascending direction.
The thickenings of the apertural margins (apertural lists) and of the ventral
margins are occasionally well shown, and certain specimens show the thickening
of the outer edge of the septum almost individualised as a continuous band or
thread (Fig. 205 e).
The virgula is very conspicuous and is generally prolonged for a distance
In the Glenkiln Shales of
Wanlock Water the virgula appears as a definite wire-like thread on the
ereater than that of the length of the polypary.
surface of the rock, but at Birnock Water and Hartfell, etc., it seems to be
GLOSSOGRAPTUS. 311
enclosed in amembrane which gives an appearance of undue breadth (Pl. XXXII,
figs. 22, 7).
Affinities —The affinities of this, the most abundant of all the British forms
Fias. 205 d—f.—Glossograptus Hincksii (Hopk.).
4 ie x 4
\ H a
SE Mac
NY ee
A Sy r if
Nia, 1 ° a E f
Pite \ 4 nN base of the spine itself. In the proximal region of
yy 4 Ns ZS ae . c :
A\ way & ay the polypary they usually extend mainly in a down-
aA ayy ward direction, but they gradually become more or
\ \ less horizontal, and in the distal region they have
a b a somewhat ascending direction. In this form we
a, Proximal end, showing disposition of
thecal spines. Enlargement of part
of Pl. XXXII, fig. 4a. .. belonging to each theca. The septal spines are not
b. Proximal end, thece somewhat dis- (SERS) hs
torted. Enlargement of part of known with certainty.
Pl. XXXIII, fig. 4c.
rarely see more than one of the two apertural spines
The sicula, which is only seen in its apertural
region, appears to extend free beyond the end of the polypary. It is provided
with two stout spines.
The sub-fusiform shape of the polypary and the disposition of the spines give
to this species a more Phyllograptid appearance than that of any of its British
congeners.
Affinities. —G. acanthus somewhat resembles G. echinatus, Ruedemann, but differs
in its more fusiform shape and in the disposition and more robust nature of its spines.
Horizon and Localities.—Arenig (zones of Didymog. bifidus and D. extensus).
Skiddaw Slates (Hllergill beds).
Lake District: Thornship Beck. 8S. Wales: Llanvirn Quarry, near St. David’s.
N. Wales: Nant-yr-Orlof, Aremg. Jreland: Sruffaunduff, half a mile W. of
summit of Bencraff, Connemara; W. end of Rossroe Peninsula, between the
Killaries; Roadside, N. end of Doolough, Co. Mayo.
Associates, etc.—Gilossog. acanthus occurs in Wales and the Lake District
associated with Didymog. bifidus, and in Ireland it has been found by Messrs. Muff
and Carruthers on a somewhat lower horizon (zone of Didyimog. extensus), asso-
ciated with Vetrag. quadribruchiatus, 1. Amu, Hallog. mucronatus var. inutilis,
Phyllograptus, ete.
Collections. —Sedgwick Museum, Muff and Carruthers, Fearnsides.
RETIOGRAPTUS. 315
Table of Specific Characters of the Genus GLOSSOGRAPTUS.
GLOSSOGRAPTUS.
G. cfr. ciliatus. G. Hincksix. G. armatus,
|
var. fimbriatus, |
|
|
Character of polypary . : . |Broad, parallel-| Fairly long, | Smaller than Small | Subfusiform,
| sided widening: typical form | widening
rapidly quickly
Maximum width . ; , P 4mm. 3 mm. 2 mm. 2 mm., uni- 4mm.
| form
Character of proximal end. 6 Broad Narrow -- With long ~-
| flexed spines
| Characters of theeee—
(1) No. in 10 mm. j : ; 10 16—10 — 9 10
(2) Apertural margin . : .| Horizontal | Horizontal or — Slightly | Everted
slightly everted everted |
(3) Ornamentation—
(a) Apertural spines Q : Long Strong arcuate — Slender, rigid | Robust, rigid,
and delicate slightly curved
(b) Septal spines. : : ? Straight, spur- = Straight, stiff |? Robust, stiff
like
Genus RETIOGRAPTUS, Hall.
1865. Retiograptus, Hall, Grapt. of Quebec Group, Geol. Survey Canada, dec. 2, p. 115.
1873. Clathrograptus, Lapworth, Geol. Mag., vol. x, p. 559.
Polypary bilaterally symmetrical, truncato-elliptical or sub-hexagonal in trans-
verse section; septal, apertural and parietal lists usually present, and
tending to form a more or less complete supporting skeletal framework or
clathria. Ventral and septal processes unknown.
Thece of the general Orthograptus type.
Test membranous, continuous, greatly attenuated.
Only two species of this genus are known in Britain. The first was originally
described by Lapworth as Clathrograptus cuneiformis. The researches of Ruedemann,
however, make it evident that this form is certainly congeneric (if not identical
with) the original Retiograptus Geinitzianus of Hall, which name has the priority,
though it is a singularly unfortunate one. The second is the form described
by Lapworth as Idiograptus aculeatus, which appears to be a very close ally of
Hall’s Retiograptus eucharis.
The affinities of Letiograptus are somewhat doubtful; it is here regarded as
being more or less intermediate between Glossograptus and Retiolites. It agrees
with Glossoqraptus in the general continuity of its test and the shape of the thece ;
but the clathria is much more strongly differentiated as such. It approaches
316
BRITISH GRAPTOLITES.
Retiolites in this last respect, but the intervening test is not reticulate as in that
genus.
Retiograptus Geinitzianus, Hall.
Plate XXXTV, figs. 7 a—d.
Reteograptus Barrandi, Hall, New York State Cab. Nat. Hist., 13th Ann. Report, p. 61,
1859. Reteograptus Geinitzianus, Hall, Pal. New York, p. 518.
1860.
figure.
1873. Clathrograptus cuneiformis, Lapworth, Geol. Mag., vol. x, p. 559.
1876. Clathrograptus cuneiformis, Lapworth, Cat. West. Scott. Foss., pl. iii, fig. 63.
1908.
pl. xxxi, figs. 9—17.
Retiograptus Geinitzianus, Ruedemann, Grapt. of New York, part 2, p. 463, pl. xxix, figs. 5, 6 ;
Polypary small, with sub-parallel margins, not exceeding 1°5 cm. in length
and widening rapidly to a maximum breadth of 2
maintained.
mm., which is then
Test continuous, greatly attenuated, but locally strengthened
by lists into a more or less complete clathria with sub-quadrangular meshes.
Sicula visible in its apertural region only.
Fias. 209 a, b, and c.—Retiograptus Geinitzianus,
Hall.
a. Complete specimen, in relief, showing sicula, both
parietal lattices, and part of one of the ventral
ones. Enlargement of part of Pl. XXXIV,
fie. 7a.
b. Compressed specimen showing clathria, enlarge-
ment of part of Pl. XXXIV, fig. 7 c.
c. Specimen showing the two ventral lattices torn
apart and twisted. Birnock Water, Glenkiln
Shales. Coll. Lapworth.
Thece fourteen in 10 mm.
Description.—The most striking charac-
teristic of this form is afforded by the
notable development of the thickening
of the salient edges and angles of the
polypary and thece, and the simultaneous
attenuation of the intervening parts of the
test. The result is that the fossil gene-
rally presents itself upon the surface of
the rock in the form of a clathria of coarse
strand-like threads and cross-bars, in the
panels of which occur patches of the
intervening attenuated membrane of the
test, which also irregularly borders or
shades and cross-bars
into the strands
themselves.
The septal strands are usually well
defined, and one Gf not both) is distinctly
agzag. The lists of the parietal lattice
are often conspicuous and generally edged
by a membrane; they have an ascending
direction, and are gently curved, arising
at a wide angle from the septal strand,
flowing the
gracefully into apparent
ventral strand, the panels thus circumscribed bemg pentagonal or sub-elliptical
RETIOGRAPTUS. 317
in shape. In examples preserved in partial relief (Fig. 209 a) the nearer composite
ventral strands form the outer visible edges of the fossil, and appear to be formed
in part of the thickened ventral edges of the successive thecze and in part of their
apertural lsts; these last when compressed give the profile a spinose appearance.
Sometimes a part or the whole of one of the ventral lattices is shown in this view
(Fig. 209). The ventral lattice itself sometimes becomes wholly detached (Fig.
209 c) and its undulating limiting strands and the cross-bars are well exhibited.
When the fossil is in low rehef (Fig. 209 w) the continuous attenuated test is
usually found preserved in the earlier parts of the polypary: when greatly
compressed little or nothing remains except the cage-like clathria (Fig. 209 b).
The transverse section of the polypary appears to have been subquadrangular
or truncato-elliptical. The thecx: were somewhat of the form of those of Ortho-
graptus, but broad towards their bases and narrowing in the direction of the
aperture, which is strongly listed. The thece were distinctly inclined; the
proximal or ventral wall of each was somewhat sigmoid, swelling out below and
bent mwards above. There are occasional traces of a short apertural mucro, but
in this species no evidences of the presence of septal spurs or processes have been
detected.
The sicula is only visible in its apertural portion, which extends outside the
polypary, and is covered by a continuous membranous test.
Affinities —Retiog. Geinitzianus is very distinct im its outward features from
any of the other British species of the Glossograptide. It most nearly resembles
ft. aculeatus, which is, however, a less compact and more straggling form.
Horizon and Localities —Liandeilo, Glenkiln Shales.
S. Scotland: Birnock Water; Head of Wandel Burn, Birnock Water; Berry-
bush Burn; Benan Burn, R. Stinchar. OC. Wales : Gwern-y-fed-fach, near Builth.
Associates, ete.—Retiog. Geinitzianus is a rare fossil in the Glenkiln Shales and
other beds on the same horizon, but when found is commonly associated with
Dicellog. sextans, Didymog. superstes, Nemag. pertenuis, N. gracilis, Climacog.
antiquus, ete.
Collections.—Lapworth, Geological Survey of Scotland, and the Authors.
Retiograptus aculeatus (Lapworth).
1880. Idiograptus aculeatus, Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, p. 168, pl. v, figs. 23 a—f.
Such specimens of this form as we have in our possession are in their present
state too poorly preserved to enable us to make out the necessary details for
figuring and description, and reference may be made to Lapworth’s original
diagnosis and illustrations (loc. cil. supra).
318 BRITISH GRAPTOLITES.
Affinities —Retiog. aculeatus (which Lapworth made the type of his genus
Idiograptus) resembles Letiog. Geinitzianus im its small size, in the tenuity of the
periderm and the development of the clathria. It 1s, however, altogether a more
lax form and the apertural spimes are more conspicuous; im one example,
indeed, some of these appear to be long and flexed and suggestive of those of
the Lasiograpti.
So far as can be gathered from the published figures and descriptions, this
form appears to be closely allied to Hall’s American species—Letiograptus eucharis
(‘Grapt. of Quebec Group,’ dec. 2, 1865, pl. xiv, fig. 9)—made classic by the
researches and observations of Ruedemann (‘Grapt. of New York,’ pt. 2, p. 397
et seq., pl. xxvi, fig. 19; pl. xxvu, figs. 11—13, etc.).
Horizon and Localities—Middle Bala, Middle Ardmillan Series, and Hartfell
Shales.
S. Scotland: Shalloch Mill, Girvan; Dobb’s Linn; Syart Law.
Associates, etc.— lvetiog. aculeatus is common in a single bed in the Middle
Ardmillan Series of Shalloch Mill, Girvan; it is rare in the Hartfell Shales of
Dobb’s Linn and Syart Law.
Collection.—Lapworth.
Genus LASIOGRAPTUS, Lapworth (extended).
1873. Lasiograptus, Lapworth, Geol. Mag., vol. x, p. 559.
Polypary bilaterally symmetrical, quadrangular to concavo-convex in transverse
section, with sub-parallel margins. Septal and ventral lists conspicuous,
appendages in the form of spines, or of fibrous processes which may
(1) remain free, (2) may be connected by a web, or (3) may anastomose
to form a more or less complete marginal lace-work.
Thece of the general type of those of Amplexograptus.
The tendency to special localisation of thickening in the periderm, which first
becomes conspicuous in the Glossograpti, and is intensified in the Retiograpti,
is developed to a remarkably high degree in the Lasiograptt. The edges and
angles of the thecee become differentiated almost into a continuous cord, filament,
or fibre, that shows through the test along the thickened selvages lke a rib in an
umbrella or the piping of a hem.
Broadly speaking, it may be said that it is this listed and fibrated structure
which is continued into, and constitutes the main element of, the extraneous
processes generally, which are more varied in form in the Lasiograpti than in any
other known group of biserial Graptolites.
LASIOGRAPTUS. 319
When they take the form of spines they are, unlike those in the Glossograpti,
always more or less flexed, and often become distinctly fibrous. These spines
appear to be always ventral in origin, septal spines or spurs like those in
Glossograptus bemg unknown in the Lasiograpti. But in place of the septal
spurs, however, there occur in two sub-genera of this group remarkable septal
processes (scopule, Hopkinson and Lapworth, 1875), each consisting of a pair of
fairly stout stem-lke fibres, which give off or break up mto branches and fibrillee,
supporting a membranous film that usually shades away at its extremity into the
surrounding rock. These scopulz appear to be identical with the ‘‘ reproductive
processes ” of Hall (Gr. [Orthog.] Whitfield). Sometimes the scopulee present the
appearance of a double membrane, web, or sac, outlined along its lower and
upper edges by a strong fibre originating as an unbranched filiform process.
Sometimes these septal processes with their sac-lke membranes are seen to arise
directly from the naked central strand well beyond the distal extremity of the
polypary (Fig. 212 0).
The ventral processes in the Lastograpti are typically mesial in origin, though
in some forms there may apparently be apertural processes in addition. In all
cases they seem to be paired, and in many cases to be formed, as it were, of the
naked prolongations of the fibrous thickening of the angles of the thecal walls
etc., the thickening extending continuously backwards to the central line or to
one of the septal strands of the polypary. When these ventral processes take
the form of spmes they may be free (Hallog. mucronatus), or each pair may
support between them a fan-like or tongue-like membrane or pelta (Hallog.
var. bimucronalus). When the ventral processes take the form of filaments or
fibres, these are in some cases free and almost straight (Uhysanog. retusus).
Generally, however, these filamentous processes are bent into a graceful declining
curve (usually convex outwards) and eventually unite with the corresponding
filaments of the processes immediately below, giving origin in this way to a
complete marginal lace-work of fine filaments, which extends continuously along
the whole ventral side of the polypary. This ventral lace-work varies much in its
details; sometimes it is fairly simple, and is formed throughout of two pairs of
sub-parallel filaments united by cross-threads (Vhysanog. Harknesst); sometimes
the filaments break up again and again to form a finer lace-work (Neurog. fibratus) ;
and in one sub-genus (Nymphograptus) the lace-work is still more complex, being
formed of long, sub-parallel strands united by fine cross-fibres, and apparently
forming a peripheral lace-work surrounding the whole of the polypary. For this
marginal lace-work we suggest the neutral term lacinia, leaving it to future
research to determine how much of it hes wholly extraneous to the ventral edges
of the thecee themselves.
Within the limits of the genus Lasiograptus as at present understood there are
but few known species; but these are so distinct in their external characteristics
320 BRITISH GRAPTOLITES.
that they appear to be naturally separable into four groups or sub-genera,
distinguished partly by the form of the thecz and partly by the nature of the
extraneous processes.
Group I.—Lasiograpti in which the thece approximate in form to those of
Glossograptus ; ventral spines and processes flexed, free or connected by a web;
septal processes when present in the form of scopulz.
= Hallograptus, Carruthers.
Type Hallograptus mucronatus.
var. wutilis.
var. bimucronatus.
sub-var. nobilis.
Group I].—Lasiograpti in which the thecz are of the typical Ampleaograptus
form; ventral processes typically united to form a complete ventral lacinia.
= Thysanograptus nov. (Lasiograptus, Lapworth).
Type Thysanog. Harknessi.
var. costatus.
retusus.
Groupe IIIl.—Lasiograptt in which the thece resemble those of Hallograptus ;
ventral and septal processes united to form a peripheral lacinia.
= Nymphograptus, Lapworth, MS.
Type Nymphog. velatus.
Group IV.—Lasiograpti in which the thece appear to be of the type of
Hallograptus ; polypary strongly clathriate; ventral processes united to form
a ventral lacinia ; septal processes, when present, in the form of scopule.
= Newrograptus, Lapworth.
Type Neurograptus fibratus.
margaritatus.
Sub-genus Hallograptus, Carruthers, MN.
1877. Hallograptus, Lapworth, Grapt. Co. Down, Proc. Belf. Nat. Field Club, p. 134.
The name Hallograptus was originally suggested by Carruthers as the title
for a genus to include the forms Diplog. mucronatus and Diplog. bimucronatus.
The name was proposed in honour of Professor James Hall, who was the first
to figure the scopulz or “reproductive sacs”? which are commonly associated
with these forms, and was first published by Lapworth in 1877.
We adopt this name as that of the first group or sub-genus of the Lasiograpti,
and include under it one species, two varieties, and one sub-variety.
LASIOGRAPTUS.
os
bo
—
Lasiograptus (Hallograptus) mucronatus (Hall). Plate XXXIII, figs. 6 a—e.
1843. Graptolithus mucronatus, Hall, Pal. New York, vol. i, p. 268, pl. Ixxiii, figs. 1 a—d.
1877. Diplograptus (Lasiograptus) mucronatus, Lapworth, Proc. Belfast Nat. Field Club, Grapt. Co.
Down, pl. vi, fig. 22.
1908.
pl. xxx, figs. 1—5; pl. xxxi, figs. 1—3.
Lasiograptus mucronatus, Ruedemann, Grapt. New York, pt. 2, p. 479, pl. xxix, figs. 9—11;
Polypary lax, having a length of 83—5 cm. and a breadth of 3 mm. exclusive of
spines. Virgella conspicuous. Thecze twelve to eight in 10 mm., having a
length of 2°5 mm. and overlapping about one half their length ; excavation
prolonged almost up to the apertural margin, which is rostrate; ventral
processes apparently apertural or sub-apertural in origin, long, slender,
flexed, and paired.
Description.—The generally lax form of the polypary is a characteristic
feature of this species.
It is fairly wide, measuring 1:2 mm. at its origin and
Fias, 210 a and b.—Hallograptus mucro. creasing at first rapidly and then more gradually
nate up to a width of 3 mm., which is thereafter con-
— | stant.
AS a ¢ ¥ ‘ 6 c
eee R, hea, The sicula has not been observed, but its posi-
NO Sh MG ey ake 2
es Re bite tion is indicated by the virgella, which, though short
Sel Die ey S| 3 F
2 he os tify and slender, is usually conspicuous, and has a leneth
ae i > 4 ? 5
— QE of ‘5mm. Th. 1! is occasionally seen to give off, in
addition to the apertural spine, a mesial spine at
a b Z
Th.
a, Proximal end, showing paired thecal
spines. Enlargement of part of PI.
XXXIII, fig. 6 d.
b. Distal thee, showing thickened
angles of ventral excavation pro-
longed into spines. Cairn Ryan,
Glenkiln Shales. Coll. Sedgwick
Museum.
the angle where upward growth commences.
1° grows obliquely across the sicula and possesses
two corresponding spines.
All the thecz have rostrate apertural margins
when compressed, and each is always provided with
a long, slender, flexed spine, the base of which is broad, and appears to be formed
by a gradual narrowing of the whole denticle. Although only one spine is usually
visible, two are occasionally shown, and there is little or no doubt that the spmes
were invariably paired. Owing to the slender and flexed nature of these thecal
spines, their direction is very variable.
It is uncertain whether any examples of this form were provided with scopule,
but judging from the number of thecz in 10 mm. it is probable that the scopulate
specimen figured on Pl. XXXIITI, fig. 6e, is referable to this form.
Affinities —The characteristic features of H. mucronatus are the curiously
loose appearance of the stipe, and the irregular direction of growth of the
spines. It presents at first sight some resemblance to Orthog. quadrimucronatus,
but the spines are more slender and more flexed than in that species, the whole
polypary is altogether less rigid and the thecz are different in form. From
42
322 BRITISH GRAPTOLITES.
its variety bimucronatus it differs chiefly in having more remote thece ; the
general plan of construction of the polypary is, however, much the same in both.
Horizon and Localities—Llandeilo, Glenkiln Shales and equivalent horizons.
S. Scotland: Glenkin Burn; Cairn Ryan; Belcraig, etc. N. Wales:
Tiddyndiewm; ‘Ty Obry.
Associates, ete.—Hallog. mucronatus is an abundant fossil at some localities
where there are good exposures of Glenkiln Shales, but as is often the case with
Graptolites from that horizon, the specimens are for the most part but poorly
preserved. Its common associates are Nemag. gracilis, Dicellog. sextans, and
Orthog. Whitfieldi.
Collections.—Sedgwick Museum, Lapworth, and the Authors.
Var. inutilis (Hall). Plate XXXII, figs. 7 a—e.
1865. Diplograptus inutilis, Hall, Grapt. of Quebec Group, p. 111.
1904. Diplograptus inutilis, Ruedemann, Grapt. of New York, pt. 1, p. 721, pl. xvi, figs. 12—13.
The form described by Hall as Diplograptus inutilis occurs in the Arenig rocks
at a few localities only in the British Isles. It
Fia. 211.—Hallograptus mucronatus, var.
inutilis (Hall). possesses, however, so many characters im common
am with Hallog. mucronatus that we believe it should be
i ; :
ae regarded as a variety of that species.
UF S ; ae
Pian The polypary is characteristically small, not
qi 2 exceeding 1°5 cm. in length, and the thece are
bal more closely set, numbermg twelve in 10 mm.,
IeRetcas alowine. cenaral fou: while the spines are shorter and stiffer than in the
pete e uaa of part of Pl. XX XIII, typical form.
: Horizon and Localities.—Arenig, Skiddaw Slates
(zones of Didymog. extensus and D. bifidus).
Treland: Sruffaunduff, half a mile west of Bencraff, Connemara. Lake
District : Outerside. S. Wales: Ditch, 100 yards 8.E. Kilnpark Farm, Narbeth.
Associates, ete.—Var. inutilis appears to be as rare a fossil in the British Isles
as it is in America. The specimens from which the above description was drawn
up were found by Messrs. Muff and Carruthers in the black shales and cherts of
Arenig age in the district round Killary Harbour. It occurs there associated
with Tetrag. Amii, T. quadribrachiatus, T. serra, Didymog. extensus, and Glossog.
acanthus. A single specimen was found in South Wales by the officers of
H. M. Geological Survey at a higher horizon associated with Didymog. artus and
Amplexog. confertus, and one specimen is known from the Skiddaw Slates.
Oollections—Geological Survey of England and Wales, Sedgwick Museum,
Muff and Carruthers.
LASIOGRAPTUS. 323
Var. bimucronatus (Nicholson). Plate XXXIII, fies. 8 a—e.
1869. Diplograptus bimucronatus, Nicholson. Ann. Mag. Nat. Hist. [4], p. 236, pl. xi, figs.
12 and 121.
1877. Diplograptus (Hallograptus) bimucronatus, Lapworth, Proc. Belfast Nat. Field Club, p. 134,
pl. vi, fig. 23.
1908. Lasiograptus bimucronatus, Ruedemann, Grapt. New York, pt. 2, p. 481, pl. xxix, figs.
12—18; pl. xxx, figs. 6—8; pl. xxxi, fig. 4.
This well-known form was originally distinguished and described by Nicholson
as a distinct species, under the title Diplograptus bimucronatus, but it presents so
many features in common with the type form of
Fie. 212 a.— Hallograptus mucronatus, o 0
Hin, Uivranta inane (NEED Hallog. mucronatus that we consider it better to
ee regard it as a variety only. It differs from H. nuucro-
natus mainly in having its thecee much more closely
set (sixteen to twelve in 10mm.), especially in the
proximal part of the polypary. In this variety the
paired nature of the spinous processes is often well
shown, and they sometimes appear as if united by a
Specimen showing scopulw and also the Membrane in the earlier part of their length.
thecal apertures. Wanlock Head,
the septal strands and extending outwards for some
Glenkiln Shales. Coll. Lapworth. The polypary varies very much in size; it some-
ee game ee times attains a leneth of 5 cm. or more, but specimens
var. bimucronatus (Nich.). with a length of about 35cm. are of most frequent
occurrence. It widens more rapidly than in the
/ typical form, and there is a tendency in some ex-
jf amples for the polypary to narrow again somewhat
La in the direction of the distal end.
exh eS Occasional specimens, which almost certainly
YY eS belong to this form but are preserved in scalariform
( view, show distinct scopulate processes arising from
|
ihe distance beyond the thecal margin of the polypary.
Dod They are apparently arranged in pairs, and occur
— - at distances answering to the position of alternate
oo a thece. As a general rule, each process seems to
ae consist of two main fibrous stems about three times
Rerentng choise bicmleat oem, te Vemigula Gs tie width of the polypary. These
end enS Gatien stems are irregularly curved and throw off at
intervals minor branches or branchlets which sup-
port between them a membranous film, the outer edges of which die away
insensibly into the surrounding rock.
324 BRITISH GRAPTOLITES.
Sometimes the scopule present rather the appearance of a bag or disc edged
and supported by simple and continuous fibres. In some examples the membrane
has disappeared, and all that remains are the supporting fibres. Examples of
scopule-bearing forms are comparatively rare, and few are sufficiently well
preserved to be figured. The scopulz themselves are apparently identical with
the “reproductive sacs”? of Hall (‘Canadian Org. Rem.,’ dec. 2, 1865, pl. 8,
figs. 6—11).
Horizon and Localities.—Llandeilo, Glenkiln Shales.
S. Scotland: Glenkiln Burn; Polmorlach Burn, Kirkconnel; Water of Deugh,
a few yards below the Moor ; foot of Hawkwood Burn, Wandel Water; Glentewing
Burn; Back Burn, Crawick Water; Gairy near head of Garryhorn Burn. Wales:
Viddyndiewm. Jreland: Belvoir, Co. Clare.
Associates, etc.— Var. bimucronatus is a fairly common fossil in certain
beds of the Glenkiln Shales of S. Scotland, where it is associated with Memag.
gracilis, Dicellog. seatans, Dicranog. rectus, Climacog. NScharenbergi, Cryptog.
tricornis, ete.
Collections.—Geological Survey of Scotland, Geological Survey of Ireland,
Sedgwick Museum, Lapworth, and the Authors.
Var. nobilis, nov. Plate XXXIII, figs. 9 a—d.
A sub-variety of Hallog. var. bimucronatus is worthy of separate description.
It is both longer and broader than var. bimucronatus, and widens so quickly that
the breadth is a conspicuous feature, even in quite
Bigs eee ee Ane young specimens which have not attained their full
length. In this form, which may be appropriately
sy “ey called var. nobilis, the length may reach 7 cm. or
“@ ~ more, and the breadth is fully 5 mm. (exclusive of
Sa ey the spinous processes) ; the margins may be parallel
sss 4 for the greater part of their length, or there may
a be a shght dimimution towards the distal extremity
es in some of the larger specimens.
ee ean eta eee Owing to their large size and good state of
largement of part of Pl. XXXIII,
Roeoe preservation the examples of this variety allow us
to interpret more perfectly the appearances pre-
sented by the spinous processes than in var. bimucronatus proper. The spines are
longer and more flexed; their fibrous extremities hang down in graceful curves,
sometimes reaching and passing beyond the level of the spines below. Some
Specimens show a septal strand distinct from the virgular tube, and short
LASIOGRAPTUS. 325
Fias. 213 b and c.—Hallograptus bimucronatus, var. nobilis, nov. processes or, more rarely,
scopule are given off from
ih this strand well beyond
EX
uN the distal extremity of the
es, polypary (Fig. 213 5). All
. \ se : ‘
\ the polyparies of this sub-
\ f variety preserved in a sub-
hs ‘ f . .
ef scalariform or scalariform
We view show scopule, and
4 - .
Rs i at the same time parts of
a Gon, e :
j “3 J Py é = the thecal spines.
yee A) ee. ae equal to more than half the
WE See 7
¢ NT. ease width of the central portion of
ASS oS) ae DS .
&. ed wy) ven (i) the polypary, and is often pre-
™~ ee ry Ss 4, 5 O
Yas) oat Ae 14-41 served complete. The main ribs
Ae ge Geto; of 1] hwork originate f
(RF cop pes; of the meshwork originate from
< PEG i
Ve f the mesial angles of the thece ;
; they have at first an ascending
a c (2)
a. Proximal end, showing well-developed lacinia. Enlarge- direction, but afterwards curve
ment of part of Pl. XXXIV, fig. 2a. A
b. Complete specimen in semi-relief, showing sicula and frag- gi acefully outward and downward,
mentary lacinia. Dobb’s Linn, Hartfell Shales (zone of Bor
Climacog. Wilsoni). Coll. Lapworth. and finally descend almost verti
c. Proximal end with test very attenuated; clathria and : is
lacinia well shown. Dobb’s Linn, Hartfell Shales. Coll. cally to anastomose with the ex
Lapworth, tremity of the processes immediately
Fias. 215 d—g—Thysanograptus Harknessi, var. costatus (Lapworth).
i A ;
aC Ne
\ iS : QU
jt
f
i 1
ad
ig)
‘L)
f
MPA dj
ao pews Y
ioe A
as ANA
d e iP g
d. Complete specimen, with lacinia very imperfectly developed. Dobb’s Linn, Hartfell Shales (zone
of Climacog. Wilsoni). Coll. Lapworth.
e. Scalariform view, showing well-developed lacinia. Hartfell Spa, Hartfell Shales (zone of Climacog.
Wilsoni). Coll. Lapworth.
Jf. Distal fragment, showing clathriate thickenings. Ibid.
g. Broad specimen, doubtfully referable to this form, with paired ventral processes united by flabellate
membranes (pelt). Dobb’s Linn?, Hartfell Shales. Coll. Lapworth.
328 BRITISH GRAPTOLITES.
below. In many cases the outer portions of the processes break up into a minor
meshwork which shows here and there traces of a connecting film. These
processes are paired, for in certain specimens a second series can be seen, fore-
shortened and interior to the first series in position.
Horizon and Localities.—Llandeilo-Bala, Glenkiln Shales—Lower Hartfell
(zone of Climacog. Wilsont).
S. Scotland: Hartfell, Dobb’s Linn; Rein Gill, Wandel Water; Cog Burn,
a few yards above junction with Polroisk. Shropshire : Oakwood, Pontesford.
Associates, etc.—Var. costatus 1s not a common fossil in beds of Llandeilo age,
but it is perhaps the commonest of the Thysanograpti present. It is fairly
abundant in the Lower Hartfell Shales (zone of Cl. Wilsoni). It occurs in
Shropshire associated with Climacog. antiquus and Mesog. multidens ; in the Glen-
kiln Shales of S. Scotland with Dieranog. rectus, Nemag. pertenuis, and Dicellog.
sevtans ; and in the Lower Hartfell Shales (zone of Climacog. Wilsoni) with the
same fossil.
Collections.—Lapworth, Geological Survey of Scotland, Mr. P. Benson.
Lasiograptus (Thysanograptus) retusus (Lapworth). Plate XXXIV, fies. 3a—e.
1880. Lasiograptus retusus, Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, p. 175, pl. v, figs. 24 a—d.
Polypary straight, about 2°5 cm. in length with average uniform breadth of
about 2mm. Thece attenuate, sixteen to fourteen in 10 mm.; excavations
wide and deep, with thickened and fibre-lhke margins; spines, when pre-
FREI tar oe ee ae served, short and stiff ; marginal lacinia
absent. Septal groove zig-zag and well
marked.
Description.—The polypary quickly attains
its maximum width of 2 mm., and afterwards
the margins are sub-parallel. The details of
the structure of the proximal end are unknown.
The thecze are markedly alternate in their
z v ¢ arrangement, and closely resemble those of
a. Proximal end, showing zig-zag septal groove nlom op PPCIN)) Q tip
and tidkenttas GE vcatval aad epecatel Aniplevog. perexcavatus, but the apertural and
margins. Hnlargement of part of PI. ntre Ton] WwW 1 7 ick
XXXIV, fig. 3a. ventral margins are occasionally thickened as
b. Distal thecw, showing virgula. Ibid. with an inner wire-like fibre, and also the line
¢. Distal thece of wider specimen, probably 2 .
referable to this species, showing con- of the zig-zag septal groove. In their form
spicuous thecal spines. Enlargement of : :
yee specimen on same slab as Pl. and mode of thickening the thecee approach
T, fig. 3c. ; :
closely to those of Thysanog. Harknessi and its
variety costatus, but though ventral spines are present a lacinia is apparently
wanting.
LASIOGRAPTUS. 5329
This form was originally described from a single specimen from the Llandeilo
Shales of the neighbourhood of Llandrindod (Pl. XXXIV, fig. 3 a). We figure
also two other specimens which may belong to this species. The one (from
Scotland) (Pl. XXXIV, fig. 3b) has rather more distant thece, the other (from
Cwm Brith. Bank, Llandrindod Wells) (Pl. XXXIV, fig. 3c) is wider (2°95
mm.) and has more closely-set thecz ; this may possibly show the obverse aspect.
9
2)
In the last example the spines are more conspicuous than in the type specimen.
Affinities —Th. retusus differs from the other Thysanograpti to which it is
allied in being a longer form, in having a distinct zig-zag septal groove, and in the
absence of a lacinia.
Horizon and Localities —Upper Arenig, Llandeilo.
Radnorshire : N.of Llandrindod Wells; N. of Cwm Brith Bank, nr. Llandrindod
Wells. S. Scotland: Hartfell Spa ?.
Associates, ete—Th. retusus occurs in the Llandeilo Rocks of Llandrindod
associated with Cryptog. tricornis, var. Schdfert, and at a somewhat lower horizon
associated with Didymog. Murchison, var. geminus.
Collections—Lapworth and Miss C. Chamberlain, Birmingham.
Sub-genus Nymphograptus, Lapworth, MS.
As only one species of this sub-genus is at present known, its characters may
in the main be regarded as typical for the sub-genus.
Lasiograptus (Nymphograptus) velatus, sp. nov. Plate XXXIV, figs. 4a and b.
Polypary relatively large, at least 4 cm. in length, widening gradually from
1 mm. to a maximum breadth of 4mm. Thece seven to six in 10 mm., of
the general type of those of Hallog. mucronatus. Septal strands very
strongly developed, extraneous processes filiform, united to form a broad
and composite lacinia completely surrounding the polypary. Test con-
tinuous, fairly thin.
Description.—Of this fairy-like species only three examples are as yet known—
one shown in the bi-profile view and two (on the same slab) in the scalariform
view.
The most striking feature of this form is presented by its remarkably
complicated lacinia. This is formed of a symmetrical arrangement of fine strands
and delicate cross-filaments. So far as can be gathered from the appearances
presented, this lacinia is composed of two main elements, namely, a first set of
43
330 BRITISH GRAPTOLITES.
curved ventral meshes apparently corresponding to the ventral meshwork in
Thysanograptus, and a second set
Fic. 217 a—ce.— Nymphograptus velatus, sp. nov.
of straight and sub - parallel
strands united with each other
and to the first set by cross
threads at fairly regular intervals.
The main filaments belonging
to the first set have the appear-
ance of prolonging the apex of
the apertural denticle, as in Hallo-
graptus. Interiorly they are
each distinctly carried backwards
continuously until they unite with
one of the septal strands of the
=I
So
op ete clathria. Exteriorly they curve
Ber Me, AN aa
ie ee ee, gracefully downwards and are
¥ aan te fe ;
x 3 eS connected with the correspond-
ms Ye
as is ; ing filaments proceeding from
\ ‘of Paeee’ a \ co) 5
\ . .
t ar y ae 24 the thece immediately below,
Je : ee as in 'hysanograptus ; there
aa aes oe Ve
“iT + \ appears also to be a secondary
reticulation on the outer side
a
of the descending fibres as in
a. Sub-scalariform view, showing form of thece. Enlargement of that sub-oenus.
part of Pl. XXXIV, fig. 4b. ‘ 5
b. Scalariform view, showing part of lacinia. Enlargement of The main filaments beloneinge
part of Pl. XXXIV, fig. 4a (left-hand specimen). eS
c. Ibid., showing lacinia in its most complete form. Enlargement to the second set appear some-
of part of Pl. XXXIV, fig. 4a (right-hand side specimen). :
what stouter. They are straight
and as a rule parallel, and have an outward and ascending direction answering
more or less to the inclination of the ventral walls of the thecz. They are of
ereat length, some of them being prolonged to a distance corresponding to the
extent of from 10 to 12 theca, and they are united by more delicate cross-threads,
usually somewhat curved and set at distances approximately equal to the distance
which separates the apertures of the thece.
Whether the straight strands of the external lattice-work originate directly
from the septal strands of the clathria in the manner of the septal processes and
scopulee of Hallograptus and Neurograptus (see postea) is not certain; but in any
case both the curved and the straight sets of filaments are united into a common
extraneous lacinia, which apparently surrounds the whole polypary.
It is probable that the parallelism of the long straight strands is not original,
but due in part to the direction im which compression has been effected, for some
of those in the proximal region certainly widen the distance between them as they
LASIOGRAPTUS. 331
proceed outward, in some cases to a breadth more than twice that between their
points of origin.
Horizon and Localities—Upper Hartfell Shales (zone of Dicellog. anceps).
S. Scotland: Kttrick Bridge End, Selkirk ; Dobb’s Linn (?).
Associates, etc.—The only three specimens of this species certainly known come
from Kttrick Bridge End and belong to the Collection of the Geological Survey of
Scotland, but fragments of a somewhat similar meshwork are not uncommon in the
zone of Dicellog. anceps at Dobb’s Linn, and may belong to the same form.
Collections.—Geological Survey of Scotland and the Authors.
Sub-genus Neurograptus, Lapworth.
1875. Neuwrograptus, Lapworth, Graptolites of the St. David’s Area, Quart. Journ. Geol. Soc., vol.
xxxi, p. 641,
Lasiograptus (Neurograptus) fibratus (Lapworth). Plate XXXIV, figs. 5 a—ce.
1876. = Retiolites fibratus, Lapworth, Cat. West. Scott. Foss., pl. iii, fig. 62.
1877. Retiolites fibratus, Lapworth, Grapt. Co. Down, Proc. Belf. Nat. Field Club, p. 136, pl. vi, fig. 28.
Polypary not exceeding 5 cm. in length, and having an average breadth of
about 3 mm. (exclusive of the extraneous processes) ; margins sub-parallel for
the greater part of their length; proximal end unknown. Thecz ten in
10 mm., of the type of those of Hallog. mucronatus. Clathria well
developed; ventral processes stout, fibrous, origimating complete marginal
lacinia; septal processes branching, scopulate. ‘Test continuous, greatly
attenuated.
Description.—The test in this species is remarkably thin, and the ribs and
processes of the clathria relatively stout and stiff, so that at first sight the entire
polypary and its appendages appear to be reduced to a network of interlacing
threads, symmetrically arranged about two strong septal strands. The central
theca-bearinge portion of the polypary, as represented by its clathria, is narrow
and inconspicuous, and must have been almost square in transverse section, for the
width in the bi-profile and scalariform views is about the same.
There are two septal strands, the most conspicuous of which is practically
straight, and the other undulating or zig-zag. In the bi-profile view, the main
filaments of the ventral lacinia proceed from the denticle, at first directly out-
wards and almost horizontally, while the descending portion is less graceful and
flowing than in most other forms of the Lasiograpti. Instead of the delicate minor
332 BRITISH GRAPTOLITES.
netting often shown in the exterior parts of the lacinia in other species, there is an
irregular outer fringe having a somewhat ragged and spinous appearance.
In the scalariform view, the
Fras, 218 a and b.—Newrograptus fibratus (Lapw.). scopulate processes are well shown,
each originating directly from one
of the septal strands. They occur
in pairs. The earlier or stem-lke
portion of each is at first hori-
ess Saar zontal, and is afterwards bent into
LO ae a curve, the convex side being up-
2: Or . wards. At a distance about equal
le BS to the diameter of the thecal portion
2 of the polypary, it branches dicho-
fs ; tomously, and the branches divide
into branchlets in their turn; traces
a. Thece in bi-profile view, showing lacinia and septal strands.
Enlargement of part of Pl. XXXIV, fig. 5 a. of an exceedingly thin membrane,
b. Sealariform view, showing straight septal strand and scopule. :
Enlargement of part of Pl. XXXIV, fig. 5 c. which once probably connected
the branches and branchlets, are
occasionally discernible.
The thece are alternate in their arrangement and strikingly recall those of
Hallog. mucronatus.
Affinities. —N. fibratus resembles closely Newrog. margaritatus, from which it
differs chiefly in being a larger form, in having a stronger and more fibrous
nature, a more attenuated test, and also scopulate septal processes.
Horizon and Localities—Bala, Hartfell Shales.
S. Scotland: Hartfell; Dobb’s Linn; ete. Ireland: Carnalea.
Associates, etc.—Neurog. fibratus occurs in the Lower Hartfell Shales in the
zones of Dicranog. Clingaim and Pleurog. linearis. It is found at the lower horizon
associated with Dicellog. Morrisi and Dicranog. vamosus, and at the higher horizon
with Pleurog. linearis and Orthog. truncatus var. pauperatus.
Collections..—Geological Survey of Scotland, Lapworth, Swanston, and the
Authors.
Lasiograptus (Neurograptus) margaritatus (Lapworth). Plate XXXIV, figs. 6a—e.
1876. Lasiograptus margaritatus, Lapworth, Cat. West. Scott. Foss., pl. i, fig. 60.
1877. Lasiograptus margaritatus, Lapworth, Proc. Belf. Nat. Field Club, p. 135, pl. vi, fig. 25.
Polypary small and limp, about 1°5 cm. in length, with an average uniform
breadth of 1°5 mm. (exclusive of the lacinia). Thecz of the type of
RETIOLITID Af. 333
Hallog.. mucronatus, alternate, fourteen to twelve in 10 mm.;_ ventral
processes slender, and united to form a continuous delicate lacinia.
Description.—The polypary is invariably short; it attaims its maximum breadth
almost at once, and maintains it to the distal extremity.
Frias. 219 a and b.—Newrograptus mar-
garitatus (Lapw.).
/
Sapte NF oh
\ Dp ADL
ee
eX
\
a b
a. Proximalend. Dobb’s Linn, Hartfell
Shales (zone of Dicranog. Clingani).
Coll. Lapworth.
b. Distal thecze, showing lacinia. En-
largement of part of Pl. XXXIV,
The thecee are of the same general form as those
of Hallog. mucronatus, but are of smaller size and
have a lesser amount of overlap. The ventral pro-
cesses arising from the denticle are delicate and
flexed, and curve broadly downward to meet those
proceeding from the theca immediately below, the
major interspaces thus formed being about the same
length as the width of the central portion of the
polypary.
series of meshes along the outer edge of the lacinia.
There is distinct evidence of a minor
No scopulate processes have been observed in this
form.
fig. 6a. 5 ono : :
: Affinities. —'This species approaches Newrog.
jibratus in the general characters of its thecee and their appendages, but, as already
pointed out, is a much smaller form; the test 1s thicker and the clathria not nearly
so pronounced, while the scopulate processes appear to be wanting.
Horizon and Localities. — Lower Bala, Lower Hartfell (zone of Dicranog.
Clingani).
S. Scotland: Dobb’s Linn, Hartfell Spa, etc.
Associates, etc.—N. margaritatus occurs in great abundance in the Hartfell
Shales associated with Dicranog. ramosus and Leptograptus jlaccidus im the zone of
Dicranog. Clingani.
Collections.—Lapworth, Geological Survey of Scotland, Swanston, and the
Authors.
Family RETIOLITIDA, Lapworth (restricted).
1873. Retiolitidxe, Lapworth, Geol. Mag., vol. x, table i, p. 555.
Biserial Graptoloidea with straight polyparies.
eraptid type.
Thece of the general Diplo-
Test represented typically by a complete network of minute
meshes supported upon a more or less well-defined skeleton or clathria of
stronger filaments.
The
network
Hxtraneous processes and lacinia absent or present.
characteristic feature of all the forms belonging to this family is the
of delicate chitinous tracery (reticula) which forms the outward visible
covering of the walls of the thecx, and is attached to the skeleton and overlies the
334 BRITISH GRAPTOLITES.
whole of the polypary with the exception of the thecal apertures. he tracery
of this reticula is sometimes filiform and subregular, but is often of irregular
breadth and outline. Its minute meshes vary mm form from circular to polygonal
and quadrangular, but there is rarely any constancy in the direction of the
component threads.
Broadly speaking, it may be inferred that this reticula represents a further
development of the tendency to the general attenuation of the test and the local
concentration of its material along more or less definite lines, resulting in a net-like
structure. In the family of the Glossograptide this tendency has originated
the clathria, and in the present family it is carried to an extreme, so that the
whole of the visible test of the polypary has become reticulate.
It may be regarded as certain, however, that the visible network of the test
in the Retiolitidee (namely, the reticula and clathria combined) does not represent
the entire thickness of the periderm. The researches of Richter, Wiman, Perner,
Sollas, ete., go to show that the periderm is composed of at least three layers [the
endochiton, the mesochiton, and the ectochiton], and that the network belongs
to the middle layer, being overspread by the outer layer and underlain by the
inner layer, both of which are membranous and continuous, but of such extreme
tenuity that they are very rarely discernible.
The clathria also attains its fullest development im the family of the Retio-
litide. That of the species Retiolites (Gladiograptus) Geinitzianus is especially
complete, and is fully representative of the original form and structure of the
polypary and thece. In many species, however, the clathria, although probably
present as such, is remarkably inconspicuous, little of it bemg preserved beyond
the septal strands and parts of the parietal lists.
A few forms afford evidence of the presence of definite interthecal planes or
floors. These are usually membranous, but are so thin as to be visible only in
rare cases.
The polypary itself varies much in form within the limits of the family ; it may
be long or short, narrow or broad. In transverse section it varies from concayo-
convex to subquadrangular.
The characters of its proximal end are rarely exhibited, but occasionally there
is evidence leading to the inference that the mode of development was similar to
that in Diplograptus. In one British species (Fig. 226 a) a well-preserved sicula
is shown, embraced as in Diplograptus by the earlier thece.
The thecze in the Retiolitidee present a considerable amount of variation in the
different species. In some (Fig. 220 ¢) they are quadrangular tubes in contact
throughout, so that four walls or sides are defined : namely, two exterior or lateral
walls (one obverse and one reverse) and two interior walls (a floor or basement
wall and a roof or covering wall). In others (Figs. 2260 and c) the terminal
portion of the theca is free as in Glyptograptus, etc., and there appears to be a
RETIOLITID A. 339
distinct impression or excavation in the middle third of its ventral wall. In
others, again, the actual forms of the thee are unknown, though occasionally
their floors are visible (Figs. 221) and c).
The apertural margins of the thecee not only vary in form in the different
species, but also in the matter of ornament. In some (Fig. 220 ¢) they are
practically destitute of ornament, im others they are provided with ventral
processes in the form of a pair of apertural spines (Figs. 226) and c); in others,
again, the ventral processes are combined into a marginal lacinia (Figs. 222 a
and c). No evidences of the existence of septal processes have Iitherto been
detected in the British forms of the Retiolitidz, nor of the possible representatives
of these processes —the septal elevations and pores (?) shown in the continental
examples of Stomatograptus.
The British species belonging to the family fall into three fairly well-marked
groups, which are typified respectively by the species Metiolites Geinitzianus, Barr.,
Tt. obesus, Lapw., and I. nassa, Holn.
In the first of these groups the thecee are quadrangular or subquadrangular in
section, and practically destitute of ornament ; in the second group the actual form
of the thecz is uncertain, but the polypary is provided with a ventral lacinia; in
the third group the thecz are flattened, steeply inclined, and occasionally spinose.
It may possibly be shown in the future that each of these groups is worthy
of generic rank, but m the meantime we class them as subgenera only.
Group I.—Retiolites in which the thee are quadrangular or sub-quadrangular
in section and practically devoid of ornament.
= Gladiograptus, Hopkinson and Lapworth.
Type Gladiograptus Getnuitzianus.
var. angustidens.
GG. perlatus.
var. Duiront.
Group I1.—Retiolites in which the form of the thecee is unknown but the
polypary possesses a ventral lacinia.
= Plegmatogrvaptus, nov.
Type Plegmatograptus nebula.
DP. obesus.
var. macilentus.
Grovur III.—Retiolites in which the thece are steeply inclined, flattened, and
occasionally spinose.
= Gothograptus, Frech.
Type Gothograptus nassa.
GF. spinosus.
336 BRITISH GRAPTOLITES.
Sub-genus Gladiograptus, Hoplinson and Lapworth.
1850. Gladiolites, Barrande, Grapt. de Bohéme, p. 68.
1875. Gladiograptus, Hopkinson and Lapworth, Quart. Journ. Geol. Soc., vol. xxxi, p. 659.
The name Gladiograptus was first suggested by Hopkinson and Lapworth
(loc. cit. supra) as a synonym for Barrande’s original name Gladiolites used by him
in the diagnosis of his Retiolites Geinitzianus ; and it is here restricted to those
forms typified by that species. ‘The sub-genus includes two British species
and two varieties.
Retiolites (Gladiograptus) Geinitzianus, Barrande. Plate XXXIV, figs. 8 a—d.
1850. (Gladiolites) Retiolites Geinitzianus, Barrande, Grapt. de Bohéme, p. 69, pl. iv, figs. 16—33.
1851. = Retiolites Geinitzianus, Suess, Ueber Bohmische Grapt., p. 95, pl. vii, figs, 1 d—e.
1852. Retiolites Geinitzianus, Geinitz, Die Graptoliten, p. 52, pl. vi, figs. 1—8.
1868. Retiolites Geinitzianus, Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, p. 580, pl. xix, figs. 19, 20.
1882. Retiolites Geinitzianus, Tullberg, Skanes Grapt., p. 41, pl. i, figs. 10—17.
1890. Retiolites Geinitzianus, Holm, Gotlands Grapt., Bihang. till k. Svensk. Vetensk.-Akad. Handl.,
vol. xvi, pt. 4, no. 7, p. 18, pl. ii, figs. 2—5.
Polypary sword-shape, robust, truncato-elliptical in transverse section, becoming
5 em. or more in length, and
concayo-convex as growth proceeds; 3
widening steadily from a rounded base to a maximum breadth of 5 mm.
Theee distinct, fourteen to nine in 10 mm., in contact throughout ; outer
walls finely reticulate, roof and floor membranous and continuous. Apertural
margins normal, quadrangular, destitute of ornament. Clathria_ well
developed, best shown in compressed specimens, the straight and zigzag
strands being usually conspicuous, especially the former. Reticula fully
developed, with sub-regular, rounded, or polygonal meshes.
Description.—The polypary in this species is sword-lke in shape, and from
specimens preserved in relief appears to have been truncato-elliptical in transverse
section at the proximal extremity, becoming more concavo-convex distally, the
central portion of the concave aspect being somewhat raised above the general
level (Barrande).
The sicula has not been observed with certainty in British examples.
The thecz are in contact throughout, and are, as a rule, mutually compressed
into the form of hollow prisms, almost square in section, and from three to four
times as long as wide.
The apertural margins are practically normal to the axis of the theea, but in
compressed specimens have the appearance of being inclined. They vary in
RETIOLITES. 397
appearance according to the amount and direction of compression ; in some cases
the ventral edge has the appearance of being straight and continuous, in others
the compressed thecal apertures appear concave and strongly mucronate.
The substance of the reticula
Fias. 220 a, b, and e.—Gladiograptus Geinitzianus (Barr.).
is thick compared with that of
other British species in this
family, and the tracery only
occasionally appears to be
actually fibrous or filamentous.
Its interspaces are irregular in
‘mand vary in number from
a. Distal fragment, showing straight and zigzag septal strands. form and ve y e
Enlargement of part of specimen from Listice, Bohemia; Etage
Ee. Coll. Sedgwick Museum.
b. Distal thece, obverse aspect, showing apertural denticles; also
texture of reticula. Enlargement of part of Pl. XX XLV, fig. 8 b.
c. Sub-scalariform view, showing ventral lattice and parietal ledges.
Enlargement of part of specimen from Répora, Bohemia. Coll.
Lapworth.
three to four within the space
limited by the distance be-
tween the floors of successive
thecee.
The clathria is often well shown in British examples of this species, but
as few of them are preserved even in semi-relief the details are difficult of inter-
pretation. Fortunately the elements of the entire clathria and their relations have
been admirably worked out for Kuropean examples by Holn, Térnquist, and
others, and reference may be made to their illustrative figures and descriptions
and also to the terminology already summarised on pp. 305, 306,
The reticula covers all the panels formed by the outer walls of the theca, and
Fias. 220 d, e, and f.—Gladiograptus Geinitzianus (Barr.).
* We
I 4
a \ex Sees
22 c\ WN ) on
a NIN 2 V4 | a
\ KL: ‘ t
Ine y
d SF
d, Restoration of proximal portion, showing clathria and parts of
reticula. (After Holm.)
e. Transverse section, showing relations of clathria and reticula.
(After Holm.)
f. Diagram of clathria only. Strands: s. Straight septal strand ;
s. zigzag septal strand; v. ventral strands. Lists: a. Apertural
or oral; 7%. interior or aboral; p. parietal. Those elements
marked (1) belong to the obverse aspect; those marked (2) to
the reverse aspect.
is attached to the parietal
lists, into which its threads
appear to graduate. It also
extends over the surface of the
central parts of the polypary
beyond the outwardly visible
limits of the parietal lists, so
that both in the obverse and
reverse aspect of the polypary,
when preserved in full or in
half relief, there is a central
longitudinal field destitute of
other structure, and the septal
strands and aboral lists are
invisible (Fig. 220 e).
Affinities, ete—Gladiog. Geinitzianus does not appear to have any close allies in
Britain with the exception of var. angustidens.
It is distinguished from all
other species by the form of the polypary and the characters of the clathria and
reticula.
Ad
338 BRITISH GRAPTOLITES.
Horizon and Localities —Gala-Tarannon and Lower Wenlock Shales, Riccarton
Beds.
S. Scotland: Grieston Quarry, Innerleithen; Kirkcudbright Bay; Falbogue
Bay, W. side Meikle Ross; Nether Stennis Water; Hsk Reservoir, Pentland
Hills. N. Wales: Conway River, W.side; Large Quarry Pen-y-glog, Dee Valley.
C. Wales: Pencerrig, near Builth; Tarannon River; Afon Jaen, near Llanbrynmarr ;
Plas bach, near Llanbrynmair, ete. Lake District: Pull Beck; Browgill; Swindale;
Stockdale, etc.
Associates, ete.—Gladiog. Geinitzianus is a common fossil in the Lower Wenlock
Shales, especially in the zone of Cyrtog. Murchisoni, where it occurs associated with
Cyrtog. Murchison, Monog. priodon, Monog. vomerinus, and other forms. It is also
found occasionally in the Tarannon Shales and their equivalents, occurring in
the zones of Monog. crenulatus, Monog. griestonensis, and Monog. crispus, associated
with the zone fossils.
Collections.—Geological Survey of Scotland, British Museum (Natural History),
Sedgwick Museum, Lapworth, and the Authors, etc.
Var. angustidens, nov. Plate XXXIV, tigs. 9 a—c.
In addition to the typical form of Gladiog. Geinitzianus, there occurs a closely
allied form which differs conspicuously in being more uniformly narrow throughout
its length ; this appears to be worthy of varietal distinction.
In this variety, which commonly reaches a length of 5 em. or more, the breadth
never exceeds 3 mm.; it is attaimed gradually from the proximal end, and the
margins are conspicuously parallel for the greater part of their extent.
Horizon and Locality—Tarannon Shale, Browgill Beds.
Lake District: Swindale. 8S. Scotland: Falbogue Bay, W. side Meikle Ross,
Karkeudbright Bay.
Vollections.—Sedgwick Museum (Coll. Fearnsides), Geological Survey of
Scotland.
Retiolites (Gladiograptus) perlatus, Nicholson. Plate XXXIV, figs. 10 a—f.
coo)
1868. Retiolites perlatus, Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, p. 580, pl. xix, figs. 21, 22.
1890. —_Retiolites cfr. perlatus, Térnquist, Acta Univ. Lund., vol. xxvi, p. 11, pl. ii, fig. 26.
Polypary with a length of 25 em., and an average uniform breadth of
5 imm.; this breadth is attained by rapid widening from the proximal end,
and the margins are distally sub-parallel. Thece sixteen to twelve in
10 mm., indistinct; floors of thecee membranous, sometimes marked by
RETIOLITES. 339
lines of growth. Clathria very ill-defined. Reticula delicate and fibrous,
with sub-rectangular meshes.
Description.—The outline of the complete polypary is generally very badly
defined, the actual positions and courses of the ventral and apertural margins
nae Oulla “ca Glanthieantan porlarle (Nick: being only identifiable at intervals.
The elements of the clathria are as a rule
almost indistinguishable, the straight septal
strand and a few of the parietal bars being the
only parts well shown. The reticula is very
delicate and fibrous, and its meshes are
eH. aa f usually sub-hexagonal. In some specimens
Aah Det (Pl. XXXIV, figs. 10 b and d), especially in the
Varta = 22
as earlier portions of the polypary, the reticula
has apparently disappeared altogether, and
what appear to be the interthecal planes or
floors of the theca are exposed, and these
form parallel bands separated from each other
by bare interspaces of about the same breadth.
These floors are membranous, and are some-
times crossed by a series of fine growth-lines.
_ This feature is very characteristic of most
a. Distal fragment, showing texture of reti- ;
cula. Enlargement of part of Pl. XXXIV, examples of the species.
fig. 10c.
b. Specimen showing the interthecal planes or Affinities.—G. perlatus somewhat resembles
floors. Enlargement of part of Pl. XXXIV, = Anwar ee ioe : .
anh ae B G, Gevuitzianus in its structure, but its different
c. Thee showing the floors marked by growth-
lines; also the zigzag septal strand. Hn-
largement of part of Pl. XXXIV, fig. 10d.
shape, its much more delicate reticula and ill-
defined clathria are well-marked distinctions.
Horizon and Locality—tlandovery, Birkhill Shales (zone of Monog. gregarius
to zone of Monog. Sedqwichit), Skelgill Beds.
Treland : Coalpit Bay, Donaghadee, Co. Down. 8S. Scotland : Duffkinnell Burn,
near Wamphray; Cramalt, Meggat Water; Dobb’s Linn, ete. Lake District :
Mosedale in Long Sleddale, Browgill.
Associates, etc.—Gladiog. perlatus is a rare fossil in the Llandovery Beds, in
which it occurs in the zone of Monog. gregarius associated with Monog. gregarius,
Petalog. minor, Climacog, Tornquisti, Cl. Hughesi, and other forms, and in the higher
zone of Monog. Sedgwicki, with M. Sedqwicku, M. convolutus, M. lobiferus, M.
discretus, Orthog. bellulus, and Climacog. scalaris.
Collections.—Belfast Museum of Natural History, British Museum (Natural
History), and Lapworth.
340 BRITISH GRAPTOLITES.
Var. Daironi, Lapworth. Plate XXXIV, fig. 11.
1877. fRetiolites perlatus, var. Daironi, Lapworth, Grapt. Co. Down, Proc. Belfast Nat. Field Club,
p. 186, pl. vi, fig. 30.
In addition to the typical form Gladiog. perlatus, there occurs at a some-
what higher horizon at Craigmichan in 8. Scotland a very much larger form
designated by Lapworth as f. perlatus, var. Dairont. ‘This form attains a length
of at least 6 cm., and a final breadth of 1:1 cm. as the result of persistent widening
from the proximal end. The thecz are much larger and more distant than in the
typical form, numbering twelve to eight in 10 mm. Only one specimen is known,
and in this the reticula is hardly discernible, but the general outline of the
polypary is well defined in the distal parts. The transverse growth-lines on the
floors of the thecz are locally distinct, especially towards the ventral margins,
and recall those on the outer walls of the thecee of Petalograptus. They appear
to be occasionally fibrous and to be crossed by others in the form of a very fine
ribbing.
Horizon and Locality.—Birkhill Shales (gone of Rastrites mains).
S. Scotland : Craigmichan.
Collection.—Lapworth.
Sub-genus Plegmatograptus, nov.
The second group of the /tetiolites includes two species and one variety in
which the shape of the thecz is unknown, but which appear to possess a ventral
lacinia. As the latter is their most obvious feature we suggest for them the
sub-generic name Plegmatograptus.
Retiolites (Plegmatograptus) nebula, sp. noy. Plate XXXIV, figs. 14 a—d.
Polypary very short and delicate, about 1 cm. in length, widening rapidly
from 1mm. at the proximal end to a maximum width of 2mm. _ Virgella
conspicuous, occasionally 3 mm. in length. Thecee twelve in 10 mm.;
their shape is indistinct, but the processes of their ventral margin give
origin to a complete and somewhat complicated lacinia. ‘The elements of
the clathria cannot be made out, and the reticula, which is but rarely
visible, is usually irregular and ill defined.
Description.—P. nebula is a very gregarious form, occurring as faint silvery
cloud-like patches upon the surface of the rock. It presents very different
RETIOLITES. 341
appearances according to the direction of compression. In the bi-profile view,
the test of the polypary seems at first sight to be continuous and to have a
nebulous and delicately membranous appearance,
Bras. 222 a, b, and c—Plegmatograptus byt when magnified it is seen to be very minutely
nebula, sp. Noy. ‘2
reticulate ; the component fibres are hardly dis-
tinguishable even under the lens in some examples,
though in others the reticulation is distinctly shown.
The ventral margins of the polypary are bordered
be by a continuous lacimia very similar to that of
alis% ) Thysanograptus Harknessi, var. costatus; but the
Bernat outer threads anastomose more frequently, and
Py * Ett rp) A : :
dgiiae occasionally appear as if covered by a faint mem-
2 ASH 2
vee.) branous film.
(2g In what appears to be the scalariform view, tl
Lape - n What appears to be the scalariform view, the
ae whole surface occupied by the fossil is covered by a
AS cioiaek i :
ae network of threads much coarser and more definite
“s) and _~with meshes larger than those of the fine
reticula above mentioned. This network may be
interpreted as representing both ventral lacinize as
shown superposed when the polypary has been com-
a. Small specimen, as seen in bi-profile
view, showing complete lacinia. pressed from the ventral aspect.
N.end of Morrach Bay, Portpatrick; ‘ . : ae :
piupell Sucks, Cra, Satay A virgella is occasionally visible, and in one
Scotland. ‘
b. Complete specimen as seen in scalari- specimen has a length of 3 mm. What appears to
form view. Ibid.
e. Specimen in bi-profile view. Hart- be the virgula is occasionally seen distally prolonged
ea ia beyond the polypary.
The thecee number twelve in 10 mm., but their shapes are very obscure.
We figure (Pl. XXXIV, fig. 14d) a larger and wider form which we pro-
visionally refer to this species. If more specimens are found this may eventually
be separated off as a distinct variety.
Affinities—The affinities of P. nebula appear to be on the one hand with
Thysanograptus Harknessi, var. costatus, and on the other with Plegmatog. obesus,
but its peculiar characters distinguish it readily from both.
Horizon and Localities —Hartfell Shales (zone of Dicranog. Clingani).
S. Scotland: Dobb’s Linn; Hartfell; N. end Morrach Bay, Portpatrick ;
Auchenvey Burn, near Ford Corsock; Burn at Gordonstown, half mile E.N.E. of
Dalry ; Wood of Cree, Newton Stewart ; Clodderoch Burn, above footpath.
Associates, etc.—Plegmatog. uebula is a very common Tfeetiolite in the Lower
Hartfell Shales of some localities in 8. Scotland, especially in the zone of Dicranog.
Clingaim, where it occurs associated with Dicellog. Morrist, D. Forchammeri, Orthog.
calcaratus, var. vulgatus, and Lasiog. margaritatus.
Collections.—Geological Survey of Scotland, Lapworth, and the Authors.
342 BRITISH GRAPTOLITES:
Retiolites (Plegmatograptus) obesus (Lapworth). Plate XXXIV, figs. 12 a—c.
1876. Retiolites perlatus, Lapworth, Cat. West. Scott. Foss., pl. iii, fig. 61.
1877. Retiolites perlatus, var. obesus, Lapworth, Grapt. Co. Down, Proc. Belf. Nat. Field Club, p. 157,
pl. vi, fig. 29.
1890. — Retiolites obesus, Tornquist, Acta Univ. Lund., vol. xxvi, p. 10, pl. ii, figs. 24, 25.
Polypary 2—8 em. in leneth, and relatively broad; havine an average uniform
e fo) > Ni ’ fo) fo)
Fias, 223 a, b, and c—Plegmatograptus
obesus (Lapw.).
LAN EEF IS.
: 4 \fr cs Dex ON
AEE
pe UES,
AN
v
ae
ay, \
a. Part of specimen showing ventral
lacinia and texture of reticula.
Elwand water, near Melrose; Gala
Group. Coll. Lapworth.
b. Bi-profile view. Enlargement of part
of Pl. XXXIV, fie. 12 a.
c. Sealariform view. Enlargement of
part of Pl. XXXIV, fig. 12 c.
breadth of about 8 mm. attamed by rapid
expansion in the proximal region. Thecee
with indistinct outlines, twelve to nine in
10 mm.; apertural mares concave, undulate;
outer margin formed of a ventral braid
apparently composed of paired inosculating
fibres. Hlements of clathria rarely show-
ing; reticula filamentous with sub-hexagonal
meshes.
Description.—The polypary is somewhat small,
but relatively very broad; the initial width does
not exceed 1'5mm., but increase takes place so
rapidly that the maximum width is quickly attained,
and the margins are then parallel for the remainder
of their extent.
What appear to be the denticles of the thecz
are occasionally well defined and thickened; they
appear to be either concave or undulate. The
ventral margin of the fossil is bordered by a broad
meshwork of curved threads which form a com-
plete marginal braiding. The main fibres of the
meshes appear to arise from the angles of the aper-
tural margins and are paired. With the exception
of its straight septal strand the clathria is ill-
defined. The reticula, however, is usually well
preserved, and is composed of irregular and some-
what wide sub-hexagonal meshes of fine thread-like
fibres.
Affinities. — P. obesus can readily be distinguished
from Plegmatog. nebula by the more robust char-
acter of the polypary, and the elegant and character-
istic shape of the regular ventral meshes.
Horizon and Localities —Gala-Tarannon.
S. Scotland: Klwand Water, near Melrose;
RETIOLITES. 343
Meigle Hill, Gala; Mount Benger Burn. C. Wales: Gelli-dywyll, near
Llanbryn-mair.
Collections.—Lapworth and the Authors.
Var. cfr. macilentus (Tornquist). Plate XXXIV, figs. 13 a and b.
1887. cfr. Retiolites macilentus, Tornquist, Geol. Foren. ForhandL., vol. ix, p. 491, fig. 3.
There occurs in the Browgill Beds of the Lake District a Metiolites closely allied
to Plegmatog. obesus, which may be compared with f. macilentus of Téornquist,
Wig) 224==Pleqmatograptus obesus, var. ond is here regarded as a variety of P. obesus.
macilentus (‘Tornq.).
It differs from the typical form chiefly in the
A character of the network, which shows very wide
and regularly arranged hexagonal meshes through-
out.
Horizon and Locality.—Gala-Tarannon, Browgill
Beds.
Lake District : Swindale Beck, Knock.
Distal fragment showing wide meshes. . . : :
Bnlargoment of partof Pl, XXX1V, Associates, etc.—Var. cfr. macilentus is a rare fossil
fig. 13. a.
oie in Beds of Gala-Tarannon age, but has been found
associated with Monog. Marri, M. continens, and Ret. (Gladiog.) Geinitzianus, ete.
Collections.—Marr, Sedgwick Museum (Coll. Nicholson and Fearnsides).
Sub-genus Gothograptus, [iech.
1897. Gothograptus, Frech, Lethea Geognostica Paleeozoica, p. 670.
The title employed for this sub-genus was proposed by Frech to include
Holm’s species of fetiolites, Rt. nassa. ‘The chief characteristic is afforded by the
form of the thece. In addition to fF. massa the group includes Let. (Gothog.)
Splnosus.
Retiolites (Gothograptus) nassa (Holm). Plate XX XLV, fies. 15 a—d.
1890. Retiolites nassa, Holm, Gotlunds Graptoliter, Bihang till k. Svenska. Vet.-Akad. Handl., vol.
xvi, pt. iv, no. 7, p. 25, pl. u1, figs. 12—14.
1897. Gothograptus nassa, Frech, Lethea Geognostica Palwozoica, p. 670.
1900. — Retiolites (Gothograptus) nassa, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 486, pl. xxv, fig.
30, and text-tig. 27.
344 BRITISH GRAPTOLITES.
Polypary compact, small and narrow, not exceeding 1°3 cm. in leneth, with an
average uniform breadth of about 1 mm. Sicula obscure, virgella long and
conspicuous. Thece fifteen in 10 mm., approaching those of Glyptograptus
or Amplexograptus in form, with small overlap; apertural margins slightly
oblique, thickened and membranous. Clathria not well differentiated ;
reticula often conspicuous, meshes extremely minute, usually regular.
Description.—The polypary is always of small size and very narrow, not
exceeding 1 mm. at its widest and tapering proximally. A prominent proximal
Fig, 225.—G@othograptus nassa (Holm). structure corresponding to Wiman’s “ initial canal”
(which may be the reticulate covering of the sicula),
is often visible, projecting somewhat beyond the
proximal end of the polypary after the manner of
the sicula of Climacog. Wilsont and other Diplo-
eraptide. The virgella is conspicuous and in one
specimen has a length of fully 2 mm.
The thecze in this species are considered by
Holm and other authors to be of the Climacograptus
type, but as the free edges of the thecv are inclined
rather than vertical, and the apertural margins
shehtly oblique, they are in form more suggestive
of those of Glyptograptus or Amplexograptus. The
thickening of the apertural margin is continued, as
in the Swedish examples, in the form of a mem-
Complete specimen, showing theew and }ranous tongue or ‘lappet” (Wiman). With the
apertural “lappets.” Enlargement : ;
of Pl. XXXIV, fig. 15 a, exception of the ventral lattice, none of the ordinary
lattices of the clathria are well defined, and the strands and cross-bars are hardly
separable from the threads of the reticula, which is here and there crossed sub-
regularly by stronger fibres than usual.
Affinities.—G. nassa differs conspicuously in size and form from all other
Retiolites except Gothog. spinosus, from which, however, it can readily be dis-
tinguished by the absence of apertural spines and by the finer meshes of the
reticula.
Horizon and Localities—Lower Ludlow Shales (zone of Monog. vulgaris).
Shropshire: Near Worthen, 8. side of Long Mountain; Elton Lane, near
Ludlow. N. Wales: Cefn-Gwyn, one mile E. of Eglwys Bach, H. side of Conway
Valley.
Associates, etc.—Gothog. nassa is a rare fossil in Britain; a few specimens only
have been found at the localities noted above; in every case it occurs associated
with Monog. vulgaris and M. dubius.
Collection.—The Authors.
RETIOLITES. 345
Retiolites (Gothograptus) spinosus (Wood). Plate XXXIV, fies. 16 a—c.
1900. Retiolites spinosus, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 485, pl. xxv, figs. 29 a and p,
and text-fig. 26 a and b.
Polypary small, not exceeding 2 cm. in length, and widening rapidly to a
maximum breadth of about 1°8 mm. (exclusive of apertural spines) which
Thecz eleven to ten
is then maintained. Sicula small, °5 mm. in length.
in 10 mm., free for greater portion of their length; apertural margins
Fias. 226 a—d.—Retiolites (Gotho-
graptus) spinosus (Wood).
a, Proximal end, showing sicula. Speci-
men on same slab as Pl. XXXIV,
fig. 16 b.
b. Complete specimen, showing sicula
and virgula, and paired apertural
spines. Figured, ‘Quart. Journ.
Geol. Soc., vol. lvi, pl. xxv, fig.
298. Coll. Elles.
c. Sub-sealariform view, showing ven-
tral lattice. Enlargement of part
of Pl. XXXIV, fig. 16 a.
d. Specimen showing clathria. Vicarage
Road, Builth; Lower Ludlow Shales.
Coll. Wood.
undulate and provided with long curved
spines. Clathria fairly well defined, reticula
somewhat coarse and irregular.
Description.—The polypary has an initial breadth
of about ‘9 mm. which increases fairly rapidly up
to 1°8 mm., which width is then maintained, so that
distally the margins are sub-parallel.
What appears to be the sicula is occasionally
visible just within the base of the reticula and has
a membranous test. It has a length of °5 mm., and
a well-marked virgula proceeds from its apex in the
normal manner. ‘This is seen to be continuous
throughout the polypary and is occasionally pro-
longed beyond its distal extremity.
In specimens in which the reticula has dis-
appeared (Fig. 226d), the clathria is well defined.
The ventral lattice, the limiting strands of which
are undulating, shows each alternate pair of cross-
bars to be connected by a median vertical fibre, the
interspaces between these apparently marking the
apertures of the theca (compare Wiman). There
are indications of two septal strands, one straight
and the other zig-zag, but the parietal lattices are
The fibration of the reti-
cula is irregular, showing comparatively wide meshes
not well differentiated.
of very fine filaments.
The apertural spines of the thece are paired,
but as a rule only one spine is visible. These spmes
always remain quite free, they are nearly as long
as the width of the polypary, and typically curve
downward, as in Hallog. mucronatus var. bimucronatus.
AS
BRITISH GRAPTOLITES.
Specific Characters of Forms belonging to the Genus Rutionirss.
Character of polypary
GROUP I = Gladiograptus.
G. Geinitzianus.
var. angustidens.
G. perlatus.
var. Daironi.
Sword-shape,
robust
Uniformly
| narrower than
typical form
Widening
rapidly from
proximal end
Very much
larger and
coarser than
typical form
9
Reticula Texture thick, — Delicate and
with fibrous, with
sub-regular subrectangular .
rounded, or meshes
polygonal |
meshes |
Clathria Well developed = Very ill ?
defined
Maximum width 5mm. 3mm 5 mm. 11 em.
No. of thecze in 10mm. 14—9 —- 16—12 12—8
GROUP II = Plegmatograptus. GROUP III = Gothograptus.
P. nebula. P. obesus. | G. nassa. G. spinosus.
var. macilentus.
- - = |
Character of polypary Cloud-like | Fairly long = Small and Rapidly
and relatively narrow with widening
broad after uniform from
rapid widen- breadth |__ proximal
ing region
Reticula Irregular | Filamentous,| Wide hexa- | Conspicuous | Coarse and
and with sub-hexa- gonal meshes meshes __—sirregular
ill defined | gonal meshes| throughout minute
near ventral
margins
Clathria Indistin- Ill defined == Ill defined — Fairly well
guishable defined
Maximum width 2mm. 8mm. == 1 mm. 18mm.
| No. of theese in 10 mm, 12 12—9 — 15 11—10
with aper-
_ tural spines
DIMORPHOGRAPTID AN. 347
Affinities.—Gothog. spinosus is readily distinguished from all other British
Retiolites by its isolated apertural spines.
Horizon and Localities—Lower Ludlow Shales (zone of Monog. Nilssont).
Wales: Hospital Road, Builth; Irfon River, Builth. Shropshire: Middletown
Brook, Long Mountain; Montgomery Road, near Chirbury.
Associates, ete.—Gothog. spinosus is a fairly common fossil in the Lower
Ludlow Shales (zone of Monog. Nilssoni) of the Welsh Borderland, where it is
found in association with Monog. Nilssoni, M. colonus, M. bohemicus, ete. Abroad
it seems to occur at a somewhat lower horizon.
Collections.—The Authors.
Family DIMORPHOGRAPTIDA, nom. nov.
1883. Family Heteroprionidx, Tullberg, Skanes Graptoliter II, Sver. Geol. Undersékn., Ser. C
No. 53, p. 14.
Oy)
Unibiserial Graptoloidea; proximal portion uniserial, bearing thecz of the
general Monograptus type; distal portion biserial, bearmg thece of the general
Diplograptus type. Test continuous, membranous.
In the Dimorphograptidz we find in combination features characteristic of the
Monograptidee on the one hand and of the Diplograptid on the other.
Proximally, the polypary im the Dimorphograptide passes through what is
practically a Monograptid stage: the proximal portion is uniserial, its earlier
thecee originate from the sicula in the same way as in Monograplus, and show the
same general low inclination and slight overlap. Distally, the polypary passes into
a Diplograptid stage, becoming biserial, as in Diplograptus, the thecze showing a
similar higher inclination and longer overlap.
In the family of the Dimorphograptidee we enter upon the fourth of the
successive types or stages in the development of the initial extremity of the
Graptoloidea in general. In the most ancient or Dichograptid type, the first theca,
after budding from the sicula, grows downward, and maintains this downward
direction throughout the whole of its growth. In the second or Leptograptid type
the first theca retains the primitive downward direction in the earlier half of its
growth, but in the later half it becomes approximately horizontal. In the third
or Diplograptid type only the initial part of the first theca retains the original
downward direction ; the middle portion is horizontal, and the terminal portion
has distinctly an upward direction of growth. In the fourth or Monograptid type
of development, here met with for the first time in the Dimorphograptide, we lose
all trace of the primitive downward direction of the first theca, the growth of
which is upward from the commencement.
348 BRITISH GRAPTOLITES.
Thus, from the systematic point of view, the Dimorphograptidee may be
regarded as constituting a family intermeciate between the Diplograptide and the
Monograptide.
The individuality of the family was first recognised by Tullberg, for whose
original title of Heteroprionide we have here substituted that of Dimorphograptide
in order to bring it into harmony with the names of the other famihes of the
Graptoloidea.
Genus DIMORPHOGRAPTUS, Lapworth.
1876. Dimorphograptus, Lapworth, Geol. Mag., dec. 2, vol. ii, p. 545.
Polypary uniserial proximally, becoming biserial distally ; test membranous
YPary , 8 >
continuous.
Thecxe of the biserial portion of the general Diplograptus type; those of the
Ss [BIO J
uniserial portion of the Monograptus type.
The polypary is somewhat small as a general rule, only two species so far as
known exceeding 3 cm. in extent. It may be curved or straight, and is biserial
iS) 5 ?
for fully one half of its entire length. The proximal uniserial portion may be
short or long, bearing from one to seventeen thecsxe, and when it is curved its
5? co)
thecx appear to be always on the convex side of the curve; fragments of this portion
J 4 8 |
are indistinguishable from some Monograpia.
There appears to be a certain amount of torsion in the polypary in some species,
so that the uniserial and biserial portions do not grow quite in the same plane.
&)
The sicula is conspicuous from its position; it is free for its entire extent on
one side, but is more or less embraced by th. 1' on the other, according as the
b b oO
first theca arises near the aperture of the sicula or near its apex. As a rule the
virgella is well shown.
The course of the virgula is easily followed ; it hes on the outer edge of the
yolypary in the uniserial portion and passes into the middle of the biserial portion.
J I
The thecze in the biserial portion of the polypary are of the general Diplo-
8 L
graptus type, but exhibit minor differences amongst themselves of much the same
nature as those which have been noticed within that genus; and consequently the
Dimorphoyraptt as a whole are capable of being similarly divided into minor
groups characterised by the differences of the thece. These minor groups are as
follows :
Grove I.—Dimorphograpti i which the biserial thece are of the general
aia 5
Orthograptus type.
Type, Dimorphog. confertus.
D. confertus.
var. Swanstont.
DIMORPHOGRAPTUS. 349
D. decussatus.
var. parliliter.
D. physophora.
D. longissimus.
Grove Il.—Dimorphograpti in which the biserial thece are of the general
Glyptograptus type.
Type, Dimorphog. erectus.
D. erectus.
D. elongatus.
Grove I1.—Dimorphograpti im which the biserial thecz are of the general
Amplevograptus type.
Type, Dimorphog. extenuatus.
D. extenuatus.
Grourv I.
Dimorphograpti 11 which the biserial thece are of the general Orthogruptus type.
Dimorphograptus confertus (Nicholson). Plate XXXV, figs. 3 a—d.
1868. Diplograpsus confertus, Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, p. 526, pl. xix, figs.
14, 15.
1888. Dimorphograptus confertus, Marr and Nicholson, Quart. Journ. Geol. 8 c., vol. xliv, p. 707,
ete.
1897. Dimorphograptus Swanstoni, var. Kurcki, Tornquist, On Diplograptide and Heteroprionidee of
Scanian Rastrites Beds, p. 19, pl. 11, figs. 33, 34.
Polypary straight or stiffly curved, 2—3 cm. in length; uniserial portion short,
bearing three thecz ; biserial portion always straight, 2—3 mm. in breadth.
Sicula conspicuous. Thece fourteen to twelve in 10 mm., with shghtly
concave outer walls overlapping one half to two thirds their length ;
apertural margins everted, undulate.
Description—The uniserial portion of the polypary has a length of about
4. mm.; it undergoes very marked increase in width from its origin towards
the biserial portion, measuring *5 mm. at the level of th. 1' and increasing to
‘8mm. It is, however, relatively slender compared with the biserial portion,
which widens from 1°8—3 mm.; distally the margins are subparallel.
The sicula has a length of 2 mm., reaching to the level of the aperture of
th. 11; the virgella is sometimes conspicuous and may have a length of 1 mm.
or more. Th. 1’ arises shghtly above the aperture of the sicula and curves
350 BRITISH GRAPTOLITES.
gradually outward; from th. 3’ two thece are developed, th. 12 from the initial
91
part of th. 3+ and th. 4" from its apertural region.
Wren ROT tHe Dnearmno craps The thecz of the biserial portion are of the
confertus (Nich.).
general Orthograptus type, and the margins are
typically undulate. The uniserial theca are more
distant than those of the biserial portion, approx1-
mating in form to those of Monograptus gregarius.
Their apertural margins are rounded and_ the
denticles are somewhat rostrate.
Affinities. —D. confertus resembles closely its var.
Swanstont, but may be distinguished by its shorter
and stiffer uniserial portion, and longer and
\ \ straighter biserial portion ; the thecz also are more
a b closely set.
a. Obverse aspect, showing sicula and Horizon and Localities.—Stockdale Shales (zone
Oe a oe ‘< of Dimorphoy. confertus), Lower Birkhill Shales
b. Obverse aspect, showing sicula and ; Ee ae Norn ate
virgella. Enlargement of part of (zone of Orthog. vesiculosus).
Ber a eee Lake District: Skelgill. S. Scotland: Dobb’s
Linn. N.H. Ireland : Mill Sluice below Slate Quarry, Tirnaskea, Co. Tyrone.
Associates, ete.—D. confertus is an abundant fossil in the beds near the base of
the Stockdale Shales at Skelgill, where it forms a well-recognised zone. The fossils
from this locality are, however, very much distorted by cleavage and the characters
of the thecze are hard to determine. Much better specimens have been obtained
from Scotland and Ireland, and from these our description has been drawn up.
It will be noticed that some of the characteristics of the species as given above
differ from those given by Nicholson in his original description, but this is
accounted for by the better preserved material subsequently collected.
Collections—Sedgwick Museum, Marr, Geological Survey of Scotland,
Lapworth, and the Authors.
Var. Swanstoni (Lapworth). Plate XXXV, figs. 4a—f.
1852. Diplograptus dentatus, Geinitz, Die Graptolithen, p. 25, pl. i, figs. 25 a and b.
1876. Dimorphograptus Swanstoni, Lapworth, Geol. Mag., p. 548, pl. xx, figs. 13 a—e.
1877. Dimorphograptus Swanstoni, Lapworth, Proc. Belfast Nat. Field Club, p. 131, pl. vi, fig. 5.
Var. Swanstoni differs from the typical species (1) in its smaller size, for it
rarely exceeds 1 cm. in length; (2) the graceful curvature of the polypary; (3) the
longer uniserial portion, which is composed of 5 thece; and (4) the greater
distance of the thecee from each other even in the biserial portion.
DIMORPHOGRAPTUS. 301
The sicula has a length of 2 mm. and the virgella 1 mm.; th. 1’ originates
slightly above the aperture of the sicula, and grows
Fias. 228 a and b.—Dimorphograptus
“fafa. sons, ROE ove (DETR) upward and very slightly outward, being closely
= adpressed to the sicula for the greater part of its
Vee
| ; length; each of the next few thece develops from
f e]
Ly
KG the theca immediately below until th. 4° or th. 5!
/ ‘i is reached ; from th. 4° (or th. 5') two thece, th. 5!
iv (or th. 6') and th. 1’ are developed, th. 1° from the
back (obverse view) of the initial portion, and th. 5!
(or th. 6') from the front and apertural region, and
“
o>
the polypary is thenceforward biserial.
a
a, Uniserial portion, obverse aspect. Hach of the biserial thecee apparently buds from
Donaghadee, Co. Down; Birkhill ; ; ; :
Shales. Coll. Elles. the theca next below it belonging to its own series ;
b. Reverse aspect. Ibid.
the septum, however, never seems to have been
more than partial throughout its entire length. In the earher part of the biserial
portion the thecz are markedly alternate, but they become less so towards the
distal end of the polypary. The apertural margins are mainly convex, but tend
to become shehtly concave towards the exterior, this double curvature being most
characteristic.
Affinities—When fully developed var. Swanstoni, with its gracefully curved
polypary, presents a most characteristic appearance. When young, however, it
is lable to be confused with specimens of Monog. gregarius until the biserial
portion commences; the thecz in these two forms are practically identical and
both have long sicule, though that of Monog. gregarius is in reality far the longer.
Amongst the Dimorphograpti, var. Swanstoni is certainly most closely allied to
Dimorphog. confertus, from which it differs chiefly in its smaller size, more graceful
curvature and less closely-set thecze.
Horizon and Localities.—Lower Birkhill Shales (zones of Cephalog. [? | acwminatus
and Orthog. vesiculosus) ; Stockdale Shales (zone of Dimorphog.confertus); Dolgadfan
Shales (Dimorphograptus band).
S. Scotland: Dobb’s Linn, ete. Lake District: Skelgill. Ireland: Coalpit
Bay, Donaghadee. C. Wales: Pennant, near Llanbrynmair.
Associates, ete.-—Dimorphog. Swanstoni is a fairly common fossil in the lower
beds of the Lower Birkhill Shales of Scotland and their equivalents m other parts
of Great Britain and Ireland. It has quite a gregarious habit in the Orthog.
vesiculosus zone, and is commonly associated with such forms as O. vesiculosus,
Dimorphog. confertus, Climacog. normalis, and Monog. tenuis. In the Scottish
specimens it 1s noticeable that the biserial portion commences after th. 47, while in
the Irish specimens there are 5 uniserial thecz. The specimens from Wales are
beautifully preserved in full relief, and there is no trace of a septal groove in the
reverse aspect.
352 BRIDISH GRAPTOLITES.
Collections.—Museum of Belfast Natural: History Society, Sedgwick Museum,
Lapworth, and the Authors.
Dimorphograptus decussatus, sp. nov. Plate XXXV, figs. 5 a
é.
Polypary 1—1:‘5 cm. or more in length, uniserial portion very short and
slightly curved, biserial portion straight, maximum breadth 2°5 mm.
Sicula conspicuous. Thecz fourteen in 10 mm., uniserial theca almost
isolated, biserial thecee of general Orthograptus type.
Description.—The character of the uniserial portion of the polypary is unique
within the genus; it is extremely short, comprising
Fias. 229 a and b.— Dimorphograptus
only 2 thece, and all the earhest thece are almost
decussatus, sp. Nov.
isolated from each other, approaching in type those
a characteristic of Monog. convolutus. In the distal
portion of the polypary, however, they are of the
u type of Orthograptus and overlap about one half their
ah, length in the normal manner. The walls of the
WB earlier biserial thecze are strongly curved, and are
WS inclined at a high angle, while those of the later ones
ah iiss
@ are straighter and inclined at a low angle. Hence
; the maximum breadth of the polypary is attained
near the commencement of the biserial portion.
a, Complete specimen, reverse aspect. :
malar gsinent of Pl. XXXV, fig. 5c. The sicula has a length of 1°7 mm., but the apex
b. Young specimen, obverse aspect, - - ;
Hawise oonialews ledeatict seala 18 often concealed by the thecal bases ; th. 1’ arises
Main Cliff, Dobb’s Linn; Birkhill .): .
Shales (Monog, tenuis band). Coll, Slightly above its aperture, and, growing upward,
” Yen specimen, obverse aspect, @Ventually bends outward somewhat abruptly ; th. oF
OEP Ta aa Shales Gone arises from th. 1’ at the bend of the latter, and
erowing outward with strong curvature has both
walls completely free ; th. 1? arises from th. 2', and growing similarly in an opposite
direction, forms an almost isolated theca on the other side of the polypary; the
next two thecz also grow in the same way, and all the proximal biserial thecz are
markedly alternate in their arrangement. After the development of th. 3' and
th. 2” a partial septum seems to make its appearance within the polypary, and the
thecz on each side develop individually from the one next below; then their walls
become straighter, and the amount of overlap increases until a constant breadth of
2 mm. is reached by the polypary.
Affinities —D. decussatus is readily distinguishable from other Dimorphograpti
by the characters of the uniserial thece.
Horizon and Localities —Lower Birkhill Shales (zone of Orthog. vesiculosus).
S. Scotland: Long Linn; Main Chiff, Branch Linn, and Corrie, Dobb’s Linn.
DIMORPHOGRAPTUS. 355
Associates, ete.—D. decussatus occurs somewhat rarely in the highest beds of the
zone of Orthog. vesiculosus associated with Climacog. rectangularis and Monog. tenuis.
Collection.—Hlles.
Var. partiliter, var. nov. Plate XXXV, fig. 6.
A variety which differs in some important respects from the typical form
Fie. 230.—Dimorphograptus decussatus, OCCUrS On approximately the same horizon. In
Yee Pari er ny this variety the uniserial portion is longer and
its thecx are not so separated from each other, only
the apertural portions of each being completely
isolated. The biserial thecze are also more distant,
numbering only ten in 10mm. As in the polypary
of the typical form, however, the maximum breadth
of 1°5 mm. is attained almost at the commencement
of the biserial portion.
Horizon.— Lower Birkhill Shales (zone of Orthog.
Reverse aspect. Enlargement of part vesiculosus).
of Pl. XXXV, fig. 6. Locality.—Dobb’s Linn.
Collection.— Hlles.
Dimorphograptus physophora (Nicholson). Plate XXXYV, figs. 7 a—d.
1868. Diplograptus physophora, Nicholson, Ann. and Mag. Nat. Hist. [4], vol. i, p. 56, pl. iii, fig. 7.
1880. Diplograptus physophora, Lapworth, Ann. and Mag. Nat. Hist. [5], vol. v, pl. v, fig. 26.
Polypary 1—3 em. in length and with maximum breadth of 2 mm., uniserial
portion very short and straight, biserial portion also straight, proximal
end enclosed in a disc; sicula long, conspicuous. Thecee nine to seven
in 10 mm., overlapping one half to two thirds their length; apertural
margins approximately horizontal.
Description.—The uniserial portion of the polypary in this species is practically
reduced to a minimum, for it is composed of only two thece. Opposite the
aperture of th. 1' the polypary measures *7 mm. in breadth; it increases up to
15 mm. at the commencement of the biserial portion, and thence widens gradually
till a breadth of 2 mm. is attained, when the margins continue subparallel for the
remainder of their extent.
The sicula has a length of 1°5 mm. and reaches well up into the biserial portion
of the polypary, terminating approximately on the level of the aperture of th. 2';
th. 1" originates shghtly above the aperture of the sicula and has the appearance
of growing at first shehtly downward, but it quickly bends round, grows upward
4.6
34 BRITISH GRAPTOLITES.
and outward. Th. 2' arises from its apertural region, and from this two thecze
are developed and the biserial portion is originated. In the reverse aspect
of the polypary it can be clearly seen that th. 1°
ie SeuEMReeaL ae grows from the initial portion of th. 2', while th. 3?
grows from its apertural region. Owing to this
growth of th. 1? a considerable portion of the
sicula is concealed in this aspect.
The whole initial region of the polypary, in-
clusive of the base of the biserial portion, is fre-
quently, though not invariably, enclosed in a disc-
like body which is approximately circular in form,
having a diameter of about 2°5 mm.
2 b The thecee number ten in 10 mm.; they have
a. Obyerse aspect, showing sicula and 20 average length of 3 mm., and the overlap
disc. Enlargement of part of speci- ; fs eta f Saale 5 5 1c
men on same slab at Pl. X¥XV, ticreases from half to two thirds in the more distal
fie. 7d. Arte = Ns ‘ ea 4
ADE al-eiseo = winlagpenient ‘of ypant parts of the polypary; the free outer walls are
XKEV fee on same slab as Fl. nearly straight, and the apertural margins are in
general slightly concave; at first they show a
tendency to slight eversion, but quickly become horizontal.
Affinities —D. physophora is the only Dimorphograptus in which a disc has
hitherto been found, and when that is preserved it 1s easily separable from all
other forms. When it is not present the polypary exhibits some features which
it shares with D. erectus. It is, however, distinguishable by its extremely short
uniserial portion and the general rigidity of the polypary.
Horizon and Locality—Lower Birkhill Shales (zone of Orthog. vesiculosus).
S. Scotland: Dobb’s Linn.
Associates, ete.—D. physophora occurs in some abundance at the top of the
Orthog. vesiculosus zone (sub-zone Monog. tenuis), associated with O. vesiculosus,
Climacog. rectangularis, Cl. innotatus, and Monog. tenuis.
Collections.—Lapworth and the Authors.
Dimorphograptus c/7. longissimus (Kurck). Plate XXXV, figs. 8 a—d.
1881. Diplograptus (?) longissimus, Kurck, Nya Grapt. fr. Sk&ue, Geol. Foren. Forhandl., vol. vi,
p- 302, pl. xiv, figs. 8 and 9.
1897. Non Diplograptus longissimus, 'Tornquist, Diplograptidee and Heteroprionide of Scanian
Rastrites Beds, p. 17, pl. ii, figs. 26—29.
Polypary 2—4 em. or more in length; biserial portion long and straight,
having a maximum width of 2—2°5 mm. which is attained quickly, so that
margins are subparallel; uniserial portion relatively short, 2°5 mm. in
length and comprising three thece, slightly curved. Sicula conspicuous.
DIMORPHOGRAPTUS. 35
Or
Thece twelve to ten in 10 mm., having an average length of 2 mm. and
overlapping one half to two thirds of their length; apertural margins of
thecze of uniserial portion characteristically rostrate; those of biserial
portion becoming straighter and the denticle more triangular.
Description.—The polypary must often have attained a great length, judging
from the extent of various fragments occasionally found; long, perfect specimens
Fra. 232.a and b.—Dimorphograptus ofr. SHOWing the proximal end are, however, rare.
Usrugassumtes(CKcancln)- These show a maximum breadth of 2°5 mm. in
the biserial portion, but numerous short examples
occur in which a breadth of 2 mm. is not exceeded.
The sicula has a leneth of 1:7 mm., reaching to
above the level of the aperture of th. 1’. The virgella
when preserved has a length of about 1 mm.
Th. 1' originates a short distance above the aper-
ture of the sicula, and grows upward with a
a b gentle outward curve; three thece are usually
a, Sicula with long virgella and th.1. developed before the biserial portion commences.
Enlargement of specimen on same 5 On0 sae
slab as Pl. XXXV, fig. 8 a. Afjinities.—When fully preserved, D. longisst-
b. Reverse aspect, showing form of ee : Oy 8
thece. Enlargement of part of Pl, 7S may be distinguished by its size from all other
ee forms except Dimorphog. physophora, from which
it differs in having more closely-set thecz and in the character of the proximal
end. Smaller specimens have, however, a superficial resemblance to D. erectus,
from which it may be separated by the rapidity with which it attains its maximum
width, and by the rostrate apertural denticles of the uniserial thecz.
Horizon and Localities —Lower Birkhill Shales (zone of Orthog. vesiculosus).
Stockdale Shales (zone of Dimorphog. confertus).
Lake District: Fruid Water, Tweedsmuir, quarter of a mile H. of Tarn Hows ;
Keisley, EH. Ridlaw. 8. Scotland : Dobb’s Linn. Ireland: Little River, Pomeroy.
Associates, ete.—Dimorphog. longissimus is commonly associated with Orthog.
vesiculosus, Dimorphog. confertus, D. Swanstoni, Climacog. rectangularis, and Monog.
tens. It is not a very abundant form.
Collections.—Sedgwick Museum, Geological Survey of Scotland, Marr, and
Hlles.
Group IT.
Dimorphograpti in which the thece are of the general Glyptograptus type.
Dimorphograptus erectus, sp. nov. Plate XXXV, figs. 9 a—d.
Polypary 1—2 cm. in length, biserial portion straight, with a maximum breadth
of 15 mm.; uniserial portion short, slightly curved, comprising 3—4
AZ
356 BRITISH GRAPTOLITES.
theex. Sicula long and conspicuous, with long virgella. Thecze ten to
eleven in 10 mm., with conspicuous sigmoid curvature, overlapping one
third to one half their length, excavations in biserial portion wide and
deep.
4mm.
Description.—The uniserial portion of the polypary has a length of 3
and measures only ‘5mm. in breadth; but the polypary widens to 1 mm. where the
biserial part commences, and thence to a maximum breadth of 1°5 mm., which is
thereafter maintained.
The sicula is very conspicuous; is about 2mm. in length, and reaches to the
level of the aperture of th. 2"; it is furnished with a long virgella which may have
a length of 4mm., and in one specimen shows a
Fias. 233 a and b.—Dimorphograptus
Sans TO dilatation at its extremity. Th. 1’ originates slightly
Ry above the aperture of the sicula, and grows upward
Nal’ and outward closely adpressed to the side of the
ay sicula ; th. 2' and th. 3' develop from the initial part
oy of the theca next below; from th. 3' (or more rarely
be th. 4") two thece arise, th. 1* from the initial portion
.) OF this or th.4 and, th. 4° -or‘th: 5) fromthe
j apertural region.
i
The thecze measure ten to eleven in 10 mm. and
have an average length of 2mm., but while in the
uniserial part they overlap one third of their length,
in the biserial portion the overlap increases to one
S : half. The thece of the biserial portion closely
a. Proximal end, obverse aspect, show. Tresemble those of Glyptog. tamariscus.
ing sicula and long virgella. Dobb’s RTS 7 aqatia Ff >
Tea ME ETT Shiaica= Geohe’ ot Affinities. —A characteristic feature of the poly-
Orthog. vesiculosus). Coll. Elles.
b. Proximal end, reverse aspect, show-
ing virgella dilating into vesicle at oradual increase in breadth, there being no sudden
its extremity. Ibid. 5
pary in both the species included in this group is its
increase where the biserial portion commences, but
a steady widening throughout from the initial portion of the uniserial part until
the maximum breadth is attained in the biserial portion. From Dimorphog.
extenuatus it is readily distinguished by the shortness of the uniserial portion.
Horizon and Localities—Lower Birkhill Shales (zone of Orthog. vesiculosus),
Stockdale Shales (zone of Dimorphog. confertus).
Lake District: Spengill Head. 8S. Scotland: Dobb’s Linn. Jreland: Little
River, Pomeroy.
Associates, ete.—Dimorphog. erectus is a fairly common fossil in the zone of
Orthog. vesiculosus of S. Scotland, where it is found associated with Dimorphog.
confertus and var. Swanstoni, Orthog. vesiculosus, and Climacog. rectangularis. In
the Lake District it has been found in the D. confertus band at Spengill Head.
Collections.
Sedgewick Museum, Marr, and Elles.
DIMORPHOGRAPTUS. 307
Dimorphograptus elongatus, Lapworth. Plate XXXV, figs. 1l a—c.
1876. Dimorphograptus elongatus, Lapworth, Geol. Mag., p. 547, pl. xx, figs. 12 a, b.
1877. Dimorphograptus elongatus, Lapworth, Proc. Belfast Nat. Field Club, p. 182, pl. vi, fig. 6.
Polypary 3°5—5 cm. in length; uniserial portion very long and curved; biserial
portion approximately straight, with a maximum breadth of 1-5 mm.
Sicula small, virgella long and conspicuous. Thece eight in 10 mm., of
the general Glyptograptus type; apertural margins introverted with acute
denticle, situated in shallow excavations occupying one quarter of the
breadth of the polypary.
Description.—The uniserial portion of the polypary is much longer than in any
other Dimorphograptus, being fully 2.5 cm. in length, and it widens gradually from
PO eT ee eat pigs ‘3mm. near the sicula till the breadth of 1°5 mm.
elongatus, Lapw. is attained.
The sicula has a length of nearly 2 mm., and
th. 1’ appears to originate from a point half way
| along its length.
{ There are commonly seventeen thecz in the
uniserial portion, th. 17' giving origin to the first
two thecve of the biserial portion; in this the thece
are alternate in their arrangement, and their aper-
tural margins seem to become more and more
introverted, and some near the distal end of the
polypary appear to be also introtorted.
Afjinities—When fully grown D. elongatus is a
a b well-characterised and easily recognisable species.
a. Proximal extremity, reverse aspect, Superficially it somewhat resembles D. exrtenuatus,
showing sicula and lone virgella. : ‘
Enlargement of part of Pl. XXXV, but differs in the curvature and length of the
fig. 116. : : ; c
b. Distal thecw. Enlargement of part Uniserial portion and in the characters of the thece.
ak ae Fragments of it are very hard to identify, for the
thecee of the uniserial portion closely resemble those of Monog. tenwis, and those
of the biserial part are not unlike those of Cephalog. (?) acuninatus, which occurs
im association with the present species.
Horizon and Localities.—Lower Birkhill Shales (zones of Cephalog. [?] acwmi-
natus and Orthog. vesiculosus) ; Stockdale Shales (zone of Dimorphog. confertus).
Lake District: Skelgill. S. Scotland: Dobb’s Linn; Craigmichan. Ireland:
Coalpit Bay, Donaghadee (?).
Associates, ete.—D. elongatus is a rare fossil at the base of the Birkhill Shales
and Stockdale Shales. It occurs associated with Cephalog. (?) acwminatus,
Dimorphog. confertus and var. Swanstoni, Orthog. vesiculosus, and Monog. tenuis.
Collections.—-Lapworth and the Authors.
358 BRITISH GRAPTOLITES.
Grovur III.
Dimorphograpti m which the thece are of the general Amplexograptus type.
Dimorphograptus extenuatus, sp. nov. Plate XXXV, figs. 10 a—e.
Polypary 2—8 cm. or more in length; uniserial and biserial portions both
sinuous; maximum breadth 1°6mm._ Sicula long, with conspicuous virgella.
Thece ten to thirteen in 10 mm. of the general Amplexograptus type, with
sharp sigmoid curvature; apertural margins opening within semi-elliptical
excavations, occupying nearly one half the breadth of the polypary.
Deseription—The uniserial portion has a length of 8mm.; it is slender,
measuring only ‘3 mm. in breadth at its origin, and widening to ‘4mm. close to the
biserial portion, so that the general increase in
Fia. 235.—Dimorphograptus eatenuatus,
eotrod width is very gradual. The biserial portion
se measures ‘7 mm. opposite the aperture of th. 1*, and
Ra widens steadily until the maximum breadth is
) attained.
A The sicula has a length of 2°5 mm. and reaches
nearly to the level of the aperture of th. 2’; the
virgella is often 2mm. in extent. Th. 1' originates
at a point some little distance above the aperture of
the sicula, which is thus free in the whole of its
apertural region. There are commonly five thecz
in the uniserial portion.
ERG eE any Mesa IniEY enoveioe: ampeet: In the biserial portion the thece are shorter and
Enlargement of part of Pl. XXXV,
aot measure thirteen in 10 mm., as opposed to ten in
g. 10d.
10 mm. in the uniserial part, and they overlap for
about one third of their length, which does not exceed 1'4mm. The distal parts of
their ventral walls are free and almost vertical, so that they resemble those of
Amplexog. perexcavatus, and come very close in form to those of a typical Climaco-
graptus.
Affinities —The characters of its thece are sufficient to distinguish D. eatenuatus
from all other Dimorphograpti.
Horizon and Localities—Lower Birkhill Shales (zone of Orthog. vesiculosus).
S. Scotland: Dobb’s Linn. Ireland: Coalpit Bay, Donaghadee. Side Valley,
Little River, Pomeroy.
Associates, etc.—D. evtenuatus occurs as a rare fossil in the Orthog. vesiculosus
zone of the Lower Birkhill Shales in 8. Scotland and N. H. Ireland. It is
commonly associated with Orthog. vesiculosus and Climacog. rectangularis.
Collections.—Museum of Belfast Natural History Society, and Elles.
PLATE XXXII.
- Sub-genera Petalograptus and Cephalograptus ; cenus Cryptograptus.
IGS.
1 a—d.— Petalograptus palmeus (Barrande). (Page 274.)
la. Typical specimen, with long virgular tube. Dobb’s Linn, 8. Scotland. Birkhill
Shales. Lapworth’s Collection.
1b. Typical specimen, showing sicula. Dobb’s Linn. Birkhill Shales (band with Monog.
Clingani). Lapworth’s Collection.
1c. Wider specimen, obverse aspect. Ibid.
ld. Wide specimen, doubtfully referable to this species. Dobb’s Linn. Birkhill Shales
(zone of Monog. gregarius). Geological Survey of Scotland, Edinburgh.
2 a—f.—Petalograptus palmeus, var. latus (Barrande). (Page 275.)
2a. Typical specimen, obverse aspect. Dobb’s Linn. Birkhill Shales. Lapworth’s
Collection.
2b. Typical specimen, reverse aspect. Ibid.
2c. Shorter specimen, somewhat compressed. Dobb’s Linn. Birkhill Shales. Sedgwick
Museum.
2d. Small specimen, figured Elles, ‘Quart. Journ. Geol. Soc.,’ 1897, vol. liii, pl. xiv, fig. 3.
Garple Linn, near Beattock. Birkhill Shales (zone of Monog. gregarius). Sedgwick
Museum.
2 e. Characteristic small specimen, showing virgella, reverse aspect. Long Linn, Dobb’s
Linn. Birkhill Shales (zone of Monog. gregarius). Elles’ Collection.
2 f. Small specimen, obverse aspect. Ibid.
3 a—d.—Petalograptus palmeus, var. tenuis (Barrande). (Page 276.)
3a. Typical specimen, cast, showing fine growth-lines. Dobb’s Linn ?, Birkhill Shales.
Lapworth’s Collection.
3b. Typical specimen, showing sicula, figured Elles, ‘Quart. Journ. Geol. Soc.,’ 1897,
vol. li, pl. xiv, fig. 9. Pull Beck, Lake District. Browgill Beds (zone of Monog.
crispus). Sedgwick Museum.
3c. Small specimen in full relief, showing sicula, ? figured Elles, Ibid., fig. 10. Dobb’s
Linn. Birkhill Shales. Lapworth’s Collection.
3d. Specimen in relief, showing no septum, reverse aspect. Morben Quarry, Derwentas,
Machynlleth. Llandovery. G. J. Williams’ Collection.
4 a—d.—Petalograptus palmeus, var. ovato-elongatus (Kurck). (Page 277.)
4a. Typical specimen, showing virgula. Long Linn, Dobb’s Linn. Birkhill Shales (zone
of Monog. gregarius). Elles’ Collection.
4b. Specimen somewhat compressed. Brauch Linn, Dobb’s Linn. Birkhill Shales (zone
of Cephalog. cometa). Hlles’ Collection. :
4c. Longer specimen, in partial relief. Dobb’s Linn. Birkhill Shales. Geological
Survey of Scotland, Hdinburgh.
4d. Incomplete specimen. Ibid.
5 a—e.—Petalograptus minor, Hlles. (Page 279.)
5 a. Typical specimen, in full relief, showmg no septum, reverse aspect, figured, Elles,
‘Quart. Journ. Geol. Soc.,’ 1897, vol. li, pl. xiv, fig. 19. Skelgill, Skelgill Beds.
Sedgewick Museum.
5 b. Similar specimen from same locality as fig. 5 a.
5 ¢. Typical specimen, obverse aspect. Long Linn, Dobb’s Linn. Birkhill Shales (zone of
Monog. gregarius). Elles’ Collection.
5 d. Larger specimen on same slab as fig. 5c.
5 e. Characteristic small specimen, showing growth-lines. Dobb’s Linn. Birkhill Shales
(zone of Monog. gregarius). Sedgwick Museum.
6.—Petalograptus cfr. ovatus (Barrande). (Page 278.)
Compressed specimen. Skelgill. Browgill Beds. Sedgwick Museum.
7 a—e.—Petalograptus altissimus, Elles and Wood, nov. (Page 281.)
7a. Typical specimen, in relief. Ettrick Bridge End, Selkirk. Upper Birkhill Shales.
Geological Survey of Scotland, Edinburgh.
7b. Less complete specimen. Dobb’s Linn. Upper Birkhill Shales (zone of Rastrites
maximus). Lapworth’s Collection.
7c. Narrow specimen, in high relief, 200 yards 8. of Parbryn Sands, Cardiganshire.
Llandovery-Tarannon. O.'T. Jones’ Collection.
7d. Distal fragment in relief. Llanystwmdwy near Criccieth. Llandovery-Tarannon
(zone of Monog. twrriculatus). Fearnsides’ Collection.
7 e. Flattened specimen. Woopland. Gala Beds. Lapworth’s Collection.
8 a—e.—Petalograptus foliwm (Hisinger). (Page 282.)
8 a. Typical specimen (faulted), reverse aspect, figured, Elles, ‘Quart. Journ. Geol. Soc.,’
1897, vol. lii, pl. xi, fig. 1. Belcraig, near Moffat. Birkhill Shales (zone of
Monog. gregarius). Hlles’ Collection.
8b. Fragment of proximal end. Main Cliff, Dobb’s Linn. Birkhill Shales (band with
P. folium). Hlles’ Collection.
PLATE XXXII—continued.
Fis.
8 a—e.—Petalograptus folinm (Hisinger) —continued.
8 c. Narrower specimen. Ibid.
8 d. Fragment of narrower specimen. Branch Linn, Dobb’s Linn. Birkhill Shales (band
with P. folium). Elles’ Collection.
8 e. Fragment of proximal end. Ibid.
9 a—d.—Cephalograptus tubulariformis (Nicholson). (Page 287.)
9a. Typical specimen, reverse aspect, figured ? Nicholson, ‘Geol. Mag.,’ 1867, pl. vii,
fig. 12, and Elles, as Cephalog. petalum, ‘Quart. Journ. Geol. Soc., 1897, vol. lu,
pl. xii, fig. 8. Frenchland Burn, near Moffat. Birkhill Shales. British
Museum (Natural History), 8. Kensington.
9b. Proximal end, reverse aspect, figured, Elles, ibid., fig. 7. Duffkinnell Burn, near
Wawphray. Birkhill Shales. British Museum (Natural History), S. Kensington.
9 ce. Long specimen. Beleraig Burn, near Moffat. Birkhill Shales (zone of Cephalog.
cometa). Elles’ Collection.
9d. Typical specimen incomplete, figured Elles, as Cephalog. petalum, ‘ Quart. Journ.
Geol. Soc., 1897, vol. lili, pl. xii, fig. 6. Duffkinnell Burn, near Wamphray.
Birkhill Shales. British Museum (Natural History), 8. Kensington.
10 a—d.—Cephalograptus cometa (Geinitz). (Page 285.)
10 a. Typical specimen partly in relief. Pary’s Mountain, Anglesea. Llandovery. G. J.
Williams’ Collection.
10 b. Very long specimen. Dobb’s Linn. Birkhill Shales (zone of Cephalog. cometa).
Lapworth’s Collection.
10 c. Well-preserved, very typical specimen. Dobb’s Linn. Birkhill Shales. Geological
Survey of Scotland, Kdinburgh.
10 d. Distal fragment, showing virgula, figured Elles, ‘Quart. Journ. Geol. Soe.,’ 1897,
vol. liii, pl. xi, fig. 10. Duffkinnell Burn, near Wamphray. British Museum
(Natural History), 8S. Kensington.
11 a—d.—Cephalograptus (?) acuminatus (Nicholson). (Page 289.)
ll a. Typical specimen. Dobb’s Linn. Birkhill Shales (zone of Cephalog. (?) acuminatus).
Lapworth’s Collection.
11 6. Smaller specimen, straighter. Duffkinnell Burn, near Wamphray. Birkhill Shales.
Lapworth’s Collection.
11 ¢. Small specimen. Dobb’s Linn. Birkhill Shales. Lapworth’s Collection.
11d. Longer straight specimen. Dobb’s Linn. Birkhill Shales (zone of Cephalog. (?)
acuminatus). Sedgwick Museum.
12 a—d.—Cryptograptus tricornis (Carruthers). (Page 296.)
12 a. Long typical specimen, poorly preserved. The Cornice, Hartfell. Hartfell Shales.
Lapworth’s Collection.
12 b. Ibid.
12 c. Smaller specimen. The Cornice, Hartfell. Hartfell Shales (zone of Climacog.
Wilsoni). Hlles’ Collection.
12 d. Small specimen. Blaen-y-delyn Quarry, Fishguard. Llanvirn Beds. F. R. C. Reed’s
Collection.
13 a—c.—Cryptograptus tricornis, var. Schdferi, Lapworth. (Page 299.)
13 a. Typical specimen. Llandrindod Wells. Llandeilo. Lapworth’s Collection.
13 6. Wider specimen. Pencerrig, near Builth. Llandeilo. Sedgwick Museum.
13 c. Same locality etc., as fig. 13 a.
14 a—e.— Crypiograptus (7?) antennarius (Hall). (Page 300.)
14 a. Typical specimen with very long basal spines. Outerside, Keswick. Skiddaw Slates.
British Museum (Natural History), 8. Kensington.
14 b. Smaller specimen, figured Elles, ‘Quart. Journ. Geol. Soc.,’ 1898, vol. liv, p. 520,
fig. 3la. Outerside. Skiddaw Slates. Sedgwick Museum.
14 c. Specimen showing additional spines, figured ibid., fig. 31. Ibid.
14 d. Specimen showing virgular tube. Ibid.
14 e. Small specimen (young), figured Elles, ibid., fig. 316. Ibid.
15 a, b.—Cryptograptus Hopkinsoni (Nicholson). (Page 299.)
15 a. Typical specimen, mentioned, Elles ‘Quart. Journ. Geol. Soc.,’ 1898, vol. liv, p. 521.
Outerside, Keswick. Skiddaw Slates. Sedgwick Museum.
15 b. Distal fragment. Ibid. British Museum (Natural History), 8. Kensington.
16 a—e.— Petalograptus (?) phylloides, Elles and Wood, nov. (Page 284.)
16 a. Typical small specimen. Beleraig Burn. Glenkiln Shales (zone of Nemag. gracilis).
Elles’ Collection.
16 b. Ibid.
16 c. Narrower specimen. Ibid. Wood’s Collection.
16 d. Specimen showing sicula. Ibid.
16 e. Young specimen with sicula. Dobb’s Linn. Glenkiln Shales (zone of Dicellog.
patulosus). HJles’ Collection.
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PLATE XXXIII.
Genus Glossograptus and Sub-genus Hallograptus.
Fras.
1.—Glossograptus cfr. ciliatus, Emmons. (Page 309.)
Small specimen (young). Ty Obry, near Portmadoc. Llandeilo.
Sedgwick Museum.
2 a—j.—Clossograptus Hincksii (Hopkinson). (Page 309.)
2a. Typical specimen, bi-profile view, showing apertural spines.
Wanlock Head. Glenkiln Shales. Lapwor th’s Collection.
Typical specimen, sub-scalariform view, showing septal and aper-
- tural spines and thread-like virgula. Ibid.
2c. Small PEE ey scalariform view showing septal spines. On
same slab as 2 a.
2d. Specimen in sub-scalariform view, showing septal spines, septal
strand, and virgula. Ibid.
2e. Young form, showing numerous spines in the proximal region.
Hartfell (?). Hartfell Shales. Lapworth’s Collection.
2f. Long specimen, with robust apertural spines. Hartfell. Hartfell
Shales (zone of Climacog. Wilsoni). Sedgwick Museum.
24. Fragment, showing septal and apertural spines. Hartfell. Hart-
fell Shales (zone of Climacog. Wilsoni). Lapworth’s Collection.
2h. Narrow specimen, bi-profile view. Ibid.
27. Short specimen, sub-scalariform view, showing septal and apertural
spines and robust virgular tube. Birnock Water. Glenkiln
Shales. Lapworth’s Collection.
Similar specimen. Ibid.
3 a—d.—Glossograptus Hincksii, var. fumbriatus (Hopkinson). (Page 312.)
3a. Typical specimen, figured Elles, ‘ Quart. Journ. Geol. Soc.,’ 1898,
vol. liv, p. 521, fig. 32. Hllergill. Skiddaw Slates (Hllergill
Beds). Sedgwick Museum.
3b. Somewhat distorted specimen. Rein Gill, Wandel Burn. Glenkiln
Shales. Geological Survey of Scotland, Edinburgh.
3¢. Young form. Minnoch Water, opposite Glencaird Lodge, W. of
Glen o’ Trool. Glenkiln Shales. Ibid.
3d. Typical specimen, broad. Wandel Water. Ibid.
4. a—c.—Glossograptus acanthus, Elles and Wood, noy. (Page 314.)
4a. Typical specimen showing robust apertural spines. Sruffaunduff,
+ mile W. of summit of Bencraff, Connemara.