(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Biodiversity Heritage Library | Children's Library | Advanced Microdevices Manuals | Linear Circuits Manuals | Supertex Manuals | Sundry Manuals | Echelon Manuals | RCA Manuals | National Semiconductor Manuals | Hewlett Packard Manuals | Signetics Manuals | Fluke Manuals | Datel Manuals | Intersil Manuals | Zilog Manuals | Maxim Manuals | Dallas Semiconductor Manuals | Temperature Manuals | SGS Manuals | Quantum Electronics Manuals | STDBus Manuals | Texas Instruments Manuals | IBM Microsoft Manuals | Grammar Analysis | Harris Manuals | Arrow Manuals | Monolithic Memories Manuals | Intel Manuals | Fault Tolerance Manuals | Johns Hopkins University Commencement | PHOIBLE Online | International Rectifier Manuals | Rectifiers scrs Triacs Manuals | Standard Microsystems Manuals | Additional Collections | Control PID Fuzzy Logic Manuals | Densitron Manuals | Philips Manuals | The Andhra Pradesh Legislative Assembly Debates | Linear Technologies Manuals | Cermetek Manuals | Miscellaneous Manuals | Hitachi Manuals | The Video Box | Communication Manuals | Scenix Manuals | Motorola Manuals | Agilent Manuals
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "Redescription of type specimens of bryozoan Stigmatella from the Upper Ordovician of the Toronto region, Ontario"

Life Sciences Contribution 07 
Royal Ontario Museum O I 

Redescription of Type 
Specimens of Bryozoan 
Stigmatella from the 
Upper Ordovician of the 
Toronto Region, Ontario 

Madeleine A. Fritz 



s;^:- 



■ 









LIFE SCIENCES CONTRIBUTIONS 
ROYAL ONTARIO MUSEUM 
NUMBER 87 



MADELEINE A. FRITZ Redescriptioii of Type Specimens 

of Bryozoan Stigmatella from the 
Upper Ordovician of the Toronto 
Region, Ontario 



Publication date: 22 January, 1973 

Suggested citation: Life Sci. Contr., R. Ont. Mus. 



ROYAL ONTARIO MUSEUM 
PUBLICATIONS IN LIFE SCIENCES 

The Royal Ontario Museum publishes three series in the Life Sciences: 

LIFE SCIENCES CONTRIBUTIONS, a numbered series of original scientific publi- 
cations, including monographic works. 

LIFE SCIENCES OCCASIONAL PAPERS, a numbered series of original scientific 
publications, primarily short and usually of taxonomic 
significance. 

LIFE SCIENCES MISCELLANEOUS PUBLICATIONS, an Unnumbered series of 
publications of varied subject matter and format. 

All manuscripts considered for publication are subject to the scrutiny and 
editorial policies of the Life Sciences Editorial Board, and to review by 
persons outside the Museum staff who are authorities in the particular field 
involved. 

LIFE SCIENCES EDITORIAL BOARD, 1971-1972 

Chairman: r. l. peterson 

Editors: j. r. tamsitt, Editor 

D, barr. Associate Editor 

E. J. crossman. Associate Editor 



MADELEINE A. FRITZ is a Research Associate in the Department of Invertebrate 
Palaeontology, Royal Ontario Museum, Toronto, Ontario. 



price: $2.50 

©The Royal Ontario Museum, 1973 

100 Queen's Park, Toronto, Canada 

PRINTED at the UNIVERSITY OF TORONTO PRESS 



Contents 

Abstract, 1 

Introduction, 1 

Materials and Methods, 2 

Systematic Palaeontology, 3 
Genus Stigmatella Ulrich and Bassler, 1904, 3 
Type species - Stigmatella crenulata Ulrich and Bassler, 1904, 4 
Stigmatella catenulata var. A, Parks and Dyer, 1922, 4 
Stigmatella halysa Armstrong, 1945, 7 
Stigmatella halysa crassa Armstrong, 1945, 10 
Stigmatella halysa erindalensis Armstrong, 1945, 11 
Stigmatella crenulata Ulrich and Bassler, 1904, 13 
Stigmatella hybrida Dyer, 1925, 14 
Stigmatella personata lobata Dyer, 1925, 17 
Stigmatella vulgaris Parks and Dyer, 1922, 20 

Acknowledgments, 23 

Tables, 24 

Literature Cited, 31 



Digitized by the Internet Arcliive 

in 2011 with funding from 

University of Toronto 



http://www.arGhive.org/details/redescriptionstigOOfrit 



Redescription of Type Specimens of 
Bryozoan Stigmatella from the Upper 
Ordovician of the Toronto Region, 
Ontario 



Abstract 

The type specimens of the bryozoan genus Stigmatella from 
the Upper Ordovician rocks of Toronto and vicinity, origin- 
ally described by Parks and Dyer (1922), Dyer (1925), and 
later restudied by Armstrong (1945), are redescribed and 
refigured according to present day standards. The specimens, 
representing eight distinct species or varieties, are located in 
the Department of Invertebrate Palaeontology of the Royal 
Ontario Museum. This fauna has not been recognized in local- 
ities outside the Toronto area. The emended descriptions and 
improved illustrations may lead to the discovery of the faunal 
assemblage elsewhere in regions where it might be expected 
to occur. 



Introduction 

The Upper Ordovician rocks that underlie Toronto and vicinity belong to 
the Georgian Bay Formation (Liberty, 1969). Formerly two formations 
were thought to be present. They were classified, in ascending order, as 
Dundas and Meaford and correlated respectively with Maysville and Rich- 
mond of Ohio. Bryozoa are abundant in these rocks. This fauna was des- 
cribed and studied by Parks and Dyer (1922) and Dyer (1925). Armstrong 
(1945) restudied the genus Stigmatella. The new species or varieties desig- 
nated by the above authors have not been recognized from outside the 
Toronto area owing to the brief, outmoded descriptions and poor illus- 
trations. I have undertaken to redescribe and refigure, according to present 
practice, the type specimens designated by the above authors. These speci- 
mens are located in the Department of Invertebrate Palaeontology of the 
Royal Ontario Museum. The more detailed descriptions and improved 
illustrations may lead to the recognition of the fauna in rocks of similar 
age in localities elsewhere. 

My paper (1970) dealt with the genus Hallopora Bassler (1911). This 
study deals with the presently known species of the genus Stigmatella found 
in the Toronto area. One variety referred to, S. catenulata diversa Parks 
and Dyer (1922), was redescribed and refigured by Fritz (1971) as Meso- 
trypa catenulata diversa (Parks and Dyer). In my opinion the term variety 
or subspecies in palaeontology, especially in rocks as old as the Ordovician, 



has no genetic significance and should not be used. But in view of the 
limited material at present available, I have redescribed and refigured the 
Stigmatella types with the nomenclature formerly proposed. It is almost 
certain that other specific variations occur in the rocks in question. In sup- 
port of this premise further careful collecting throughout the formation 
would be necessary. 



Materials and Methods 

The type specimens of eight taxa of the genus Stigmatella are redescribed in 
the following order: 

Stigmatella catenulata var. a Parks and Dyer (1922) 

Stigmatella halysa Armstrong, 1945 (= S. catenulata var. B Parks and 
Dyer (1922)) 

Stigmatella halysa crassa Armstrong, 1945 (= S.sessilis crassa Dyer, 
1925) 

Stigmatella halysa erindalensis Armstrong, 1945 

Stigmatella crenulata Ulrich and Bassler (1904) 

Stigmatella hybrida Dyer (1925 ) 

Stigmatella personata lobata Dyer (1925 ) 

Stigmatella vulgaris Parks and Dyer (1922) 

In addition to the above species, three other forms of Stigmatella were 
described by the early writers: 

S.alcicornis Cumings and Galloway (1913, p. 436) 

S.ci.clavis (Ulrich, 1883, p. 161) 

S.lambtonensis Parks and Dyer (1922, p. 14) 
S.alcicornis was identified by Armstrong (1945, p. 150) from a single, 
poorly-preserved specimen. My examination of the specimen leads to the 
conclusion that the species is indeterminable. 

LOCALITY — Humber member, Dundas Formation at Humbervale quarry, 
near Toronto. 
TYPE — Plesiotype rom 1180hr. 

S.ci. clavis (Ulrich, 1883, p. 161 ). The identification by Parks and Dyer 
(1922, p. 16) was based mainly upon external features of three specimens, 
in each the zoarium being chub-shaped. Armstrong (1945, p. 151) sug- 
gested a relationship with S. halysa. Additional material would be necessary 
to validate the species. 

LOCALITY — 16-foot Icvcl, Humbcrvalc quarry. 
TYPE — Plesiotype rom 1 183hr. 

S.lambtonensis Parks and Dyer (1922, p. 14). The authors based their 
diagnosis upon a single specimen now known to represent a species of the 
genus Dekayia Armstrong (1945, p. 153). Vertification of this identification 
is possible only when further specimens are recovered. 
LOCALITY — 5-foot level, old shale pit, Lambton, Ontario. 
TYPE — Holotype rom 1090. 



External features of specimens were examined either by the naked eye 
or with the aid of a hand lens. Microstructure was determined by means of 
thin sections. Mensuration for the number of zooecia in 2 mm in the inter- 
monticular areas and the measurements in mm of maximum zooecial aper- 
tures in the monticular and intermonticular areas were carried out with the 
aid of a binocular microscope and a micrometer scale calibrated to 0.01 mm. 
The number of entire acanthopores in 1 mm^ and the number of entire 
mesopores in 1 mm- were obtained by using a compound microscope and a 
reticle calibrated to 1 mm-. The mean, standard error, and standard devi- 
tion were computed on a Monroe 990 desk calculator (Monroe - The Com- 
puter Company, Orange, New Jersey). Student's Mest was employed to 
show significance of differences between means (Simpson et al., 1960). 



Systematic Palaeontology 

Order trepostomata Ulrich 1882 

Family heterotrypidae Ulrich 1890 

Genus Stigmatella Ulrich and Bassler, 1904 

Ulrich and Bassler's description of Stigmatella follows: 

"Zoarium variable, ranging from incrusting to irregularly massive and 
ramose. Zooecia angular, rounded, or irregularly petaloid, the shape depend- 
ing upon the presence (or absence) of mesopores and the number of acan- 
thopores. Typically the zoarial surface exhibits at regular intervals maculae 
or spots composed of mesopores, although in some species the usual monti- 
cules or clusters of large cells occur. Acanthopores always present but 
variable in number, intermittent, developed chiefly in narrow zones, some- 
times inconspicuous but more often so numerous as to give the surface a 
decidedly hirsute appearance. Mesopores, when present, developed in ma- 
ture regions only, their number being variable even for the same species. 

"The zooecial tubes have thin walls in the axial region and these become 
but slightly thickened in the peripheral region where a few unusually deli- 
cate diaphragms are inserted. In vertical sections the walls exhibit at rather 
regular intervals in the peripheral region thickenings somewhat similar to 
those occurring in Stenopora. These thickenings occur aproximatcly at the 
same height in the walls, and tangential sections through these zones give 
the full development of acanthopores. Minute structure of walls as shown in 
tangential sections, of the type that characterizes the Heterotrypidae'' 



Type species - Stigmatella crenulata Ulrich and Bassler, 1904 
Stigmatella catenulata var. A, Parks and Dyer, 1922 

(Fig. 1 B,c) 

Stigmatella catenulata Cumings and Galloway, 1913, p. 437. 
Stigmatella catenulata var. A Parks and Dyer, 1922, p. 13, pi. 3, figs. 1, 2. 
Stigmatella catenulata Armstrong, 1945, p. 150. 

Cumings and Galloway's description: 

"Zoarium robust, subramose, 1.5 to 2 cm in diameter and 5 or 6 cm long. 
Surface nearly smooth, with low, round monticules or large maculae, com- 
posed of mesopores and large zooecia. Zooecia subcircular, with medium 
thin walls. Mesopores are usually restricted to the clusters, but sometimes, 
on immature branches, there may be a small area in which mesopores are 
numerous. 

"Tangential sections show the zooecia to be subpolygonal and thin 
walled, with a light-coloured intermural line; 9 zooecia in 2 mm. Where 
there are mesopores the zooecia are smaller, but there is the same number 
in 2mm, including mesopores. The acanthopores are small but conspicuous, 
about half the size of number 1, that is, 1/40 mm in diameter, about 10 in 10 
zooecia. They are situated at the angles of junction of the zooecia and never 
inflect the zooecial wall. Mesopores are usually few or absent in sections 
near the surface, but occasionally a section will show a region of numerous 
mesopores, especially if the section is deep or taken from an immature 
branch. 

"Diaphragms are absent in the axial region and there are only one or 
two in the mature region. The zooecial walls are only slightly thickened in 
the mature region, which is 2 or 3 mm in depth. The chain-like mesopores 
are the noticeable feaure of longitudinal sections. They begin in the sub- 
mature region and ordinarily do not reach the surface. Where the dia- 
phragms cross the mesopores there is a constriction, giving to the mesopores 
the appearance of chains or strings of beads. The zooecial walls are nearly 
straight or only slightly flexuous. 

"This species is evidently most closely related to Stigmatella interporosa 
Ulrich and Bassler, which it resembles, but it may be distinguished from 
that species by its more rebust [sic] habit of growth, thicker mature region 
and less numerous mesopores and greater development of chain-like 
mesopores." 
Parks and Dyer's description: 

"Species of Stigmatella showing distinct chain-like mesopores are of 
frequent occurrence in the rocks at Toronto. The only species in which the 
character is pronounced are: S .interporosa Ulrich and Bassler, S.sessilis 
Cumings and Galloway, and S. catenulata Cumings and Galloway. All of 
our specimens are distinct from S. interporosa as the great development of 
mesopores characteristic of that species is not seen. One of them resembles 
S.sessilis, and three others approach so close to S. catenulata that they are 
included in that species although varietal differences are marked. 



B 



pr^-r 













X.' / 




J 






/ 



f 



^ *-. 




Fiy:,. I — Stigmatella halysa crassa Dyer, holotype rom 1292hr. A. Longitudinal 
section, X30. Stigmatella catcnulata var. a Parks and Dyer, holotype rom 
1087HR. B. Longitudinal section, x3(); C. Tangential section, x30. 



"The first type which we may call Variety (A) approaches most closely 
to typical S.catemdata. The zoarium is irregularly ramose, with flattened 
branches which appear to be hollow. An average branch is about 1 5 mm by 
8 mm. The surface is marked by very small and inconspicuous monticules, 
2 to 3 mm apart. 

"Tangential sections show groups of larger, thin-walled, polygonal zoo- 
ecia to the number of nine in a space of two millimetres, and areas with 
considerably smaller and more rounded zooecia with frequent mesopores. 
As many as twelve zooecia were counted in the space of two milHmetres. 
Sections very near the surface present almost exactly the appearance of 
Cumings and Galloway's figures except that the acanthopores are not rigidly 
confined to the angles of the zooecia. Sections at moderate depth show 
scattered large acanthopores; many of them not at the angles of junction, 
and strongly inflecting the zooecial cavity. Sections cut at a still deeper level 
are almost devoid of acanthopores. 

"Vertical sections show that the tube wafls increase very little in thickness 
towards the surface and that the characteristic chain-like mesopores are 
well developed. Diaphragms in the zooecial tubes are of rare occurrence. 

"This variety differs from the type only in the character of the acantho- 
pores and in the more rugose surface." 

Emended description 

EXTERNAL FEATURES — Zoarium a small, somewhat fan-shaped growth en- 
crusting crinoid stem, height 27 mm, width at base 9 mm, width at summit 
21 mm, maximum thickness at mid-height 14 mm. Surface elevations, with 
basal diameter 3-5 mm, represent aborted branches. Small monticules occur 
at intervals of 2-3 mm. 

TANGENTIAL SECTION — Zooccial apcrturcs angular in deep sections where 
wall thin; subangular to subcircular, at times nearly circular in sections near 
zoarial surface where wall thickness and in places slightly inflected by 
acanthopores, mostly 8-1 1 zooecia in 2 mm in intermonticular space (Table 
1 ); zooecial walls in deep sections 0.01 (or less) to nearly 0.02 mm thick, 
toward surface 0.02-0.05 mm thick, to 0.07 mm thick in monticules, wall 
concentrically laminated, median band commonly light in colour. Mesopores 
few to relatively numerous (Table 1), mostly triangular to rectangular and 
often in pairs. Acanthopores moderately abundant (Table 1), locally in- 
flecting, 0.01—0.06 mm in diameter, with central lumen surrounded by 
dense, concentric laminae, from four to six located at junction of three 
adjacent zooecia. Monticules with larger zooecia than in intermonticular 
areas (Table 1). 

LONGITUDINAL SECTION — Zooccia generally subprostrate for a short dis- 
tance from base, then straight to surface, where they open at right angles or 
nearly so; walls mostly straight, monilae rare; wall thin in axial region, thick- 
ening from base of peripheral zone; laminae of wall sharply convex outward, 
diverging from line of demarcation at moderately low angle and passing 
into diaphragms. Diaphragms horizontal, rare, but owing to crystaUization 
others may possibly have been destroyed. Chain-like mesopores prominent 



throughout. Acanthopores in both axial and peripheral zones, lumen sur- 
rounded by laminae, convex outward, diverging at a low angle. 
REMARKS — The small, somewhat fan-shaped, encrusting zoarium readily 
distinguishes this variety from S.catenulata Cumings and Galloway (1913), 
which is a robust, ramose, non-encrusting form from the Richmond, Cuts 
10 and 11, Harmon's Station, Indiana. Externally S.catenulata var. a more 
closely resembles SAncrustans Cumings and Galloway {op. cit.) from the 
Richmond, Cut 17, Weisburg, Indiana, but is distinguished from that species 
by smaller zooecia, fewer diaphragms, and more numerous mesopores. 
Furthermore, both S.catenulata and S.incrustans are found at a higher 
horizon than is the present variety. S.catenulata var. a is related to S.catenu- 
lata var. B Parks and Dyer 1922 (= S.halysa Armstrong, 1945) and also to 
S.sessilis crassa Dyer 1925 (= S.halysa crassa Armstrong, 1945), which 
occur in associated rocks. Significant differences are indicated in Table 1. 

In that Stigmatella catenulata var. a differs from known species or varie- 
ties, it should probably be given the rank of species, but I hesitate to create 
a new taxon on evidence provided solely by the holotype. 
LOCALITY — Dundas Formation, Humber Member, Upper Ordovician, 
Lambton, Ontario. 
TYPE — Holotype ROM 1087HR. 

Stigmatella halysa Armstrong, 1945 

(Fig. 2A-D) 

Stigmatella catenulata Cumings and Galloway, 1913, p. 437. 
Stigmatella catenulata var. B Parks and Dyer, 1922, p. 13, pi. 3, fig. 3. 
Stigmatella halysa Armstrong, 1945, p. 153, 154, text-figs. 5, 12. 

Armstrong's description follows : 

"Zoarium incrusting; type specimen encircles crinoid column for at least 
90 mm; maximum thickness 22 mm; resultant form somewhat cyHndrical, 
tapering slightly to each end; surface nearly smooth, but showing some 
inconspicuous, low rounded elevations spaced irregulaily; zooecial open- 
ing in elevations slightly larger than elsewhere. 

"Two sizes of zooecia in tangential section; larger 8 in 2 mm, smaller 10 
or 11 in 2 mm; openings circular to subcircular, walls moderately thick. 
Acanthopores numerous, about 10 in 10 zooecia; mostly in angles of 
junction, but found slightly inflecting walls of zooecia; size no. 1 in Cumings 
and Galloway's scale, that is, about 1/20 mm in diameter; central lumen 
clear, about 1/75 mm in diameter. Mesopores rather common, suggestion of 
aggregation in one spot in type. 

"Vertical sections indicate zooecia have thin, straight walls with char- 
acteristic periodic thickenings; featured by chain-like mesopores beginning 
at mid-radius, continuing to periphery of zoarium; number of 'links' 4 to 15. 
Acanthopores numerous, traceable almost into axial region; diaphragms 
sparsely developed, tending to appear simultaneously in all zooecia; no note- 
worthy peripheral thickening of walls. 

"Parks and Dyer (1922) recognized this form as S.catenulata Var. B. 
The specific name has been given in recognition of the characteristic chain- 



like mesopores. This species resembles S.catemdata from which it may be 
distinguished chiefly by its habit of growth, and by the size and distribution 
of acanthopores, which in S.catenulata are small, inconspicuous and re- 
stricted to the angles of junction of the zooecia." 

Emended description 

EXTERNAL FEATURES — Zoarium Cylindrical or pipe-shaped, 90 mm long, 
overgrowing a centrally located crinoid stem; maximum thickness of en- 
crustation 9 mm. Surface eroded but small monticules still visible, 2-2.5 
mm apart when measured from centre to centre, and consisting of larger 
zooecia than in intermonticular space. 

TANGENTIAL SECTION — Zooccia angular in deep sections where wall thin, 
subangular to subcircular near surface where wall thicker, usually 8-10 
zooecia in 2 mm in intermonticular space (Table 1 ); zooecial walls in deep 
sections 0.01 mm (or less) thick, 0.02-0.05 mm near surface and sHghtly 
thicker in monticules, the wall concentrically laminated with light-coloured 
central ring. Mesopores few to moderately numerous (Table 1), in monti- 
cules often in clusters. Acanthopores relatively abundant, 0.01-0.04 mm 
in diameter, five may occur where four zooecia in conjunction, some slightly 
inflect the zooecial wall. Zooecia in monticules larger than those in inter- 
monticular space (Table 1 ). 

LONGITUDINAL SECTION — Initially zooecia prostrate, then curve broadly 
and later straighten to intersect zoarial surface nearly at right angles; zoo- 
ecial walls straight, thin in axial zone where monilae appear at regular 
horizons across section; walls thicken slightly from base of peripheral zone 
to surface; wall laminae sharply convex outward, diverging from median 
light-coloured band at moderately low angle and passing into diaphragms. 
Diaphragms few, generally horizontal, widely spaced, in general two in 
each growth period. Chain-like mesopores conspicuous. Structure of acan- 
thopores similar to that of zooecial wall. 

REMARKS — Stigmatella halysa Armstrong (1945) (= S.catenulata var. B. 
Parks and Dyer, 1922) and S.catenulata var. a Parks and Dyer are similar 
species. Zooaria in each encrust a crinoid stem. In S. halysa the zoarial shape 
is cylindrical or pipe-shaped, and small, low monticules often with central 
clusters of mesopores, are present. In S.catenulata var. a, the zoarium is 
fan-shaped, giving rise to aborted branches, and monticules are well-defined, 
without central concentration of mesopores. Armstrong (1945) considered 
S.sessilis crassa (Dyer, 1925) to be a variety of S. halysa, basing his con- 
clusion solely on the manner of growth of that species, but as shown in 
Table 1 , when the two are compared they differ in number of zooecia in 2 
mm, measurement of maximum zooecial apertures in monticules or macu- 
lae, measurement of maximum zooecial apertures in the intermonticular/ 
intermacular areas. As indicated in the description of S. halysa crassa, the 
three species here mentioned are compared in pairs in Table 1. 
LOCALITY — Dundas Formation, Humber Member, Upper Ordovician, 
Lambton, Ontario. 
TYPE — Holotype rom 1088hr. 



8 







'\.^mi''n; 






^■4 i -». 




.^ 



-' -.-■ ,> ^ 






/ - 



#- ^ 






^1* •: "> 



« ~' w V- 



f'^H- - — Stii^matella halysa Armstrong, holotype ROM I088hr. A. Tangential 
section, x30; B. Longitudinal section, x30; C. Longitudinal section, X30; D. 
Tangential section, X30. 



Stigmatella halysa crassa Armstrong, 1945 

(Figs. 1a, 3d) 

Stigmatella sessilis crassa Dyer, 1925, p. 72, pi. 6, fig. 10. 
Stigmatella halysa crassa Armstrong, 1945, p. 154, text-figs. 6, 7. 

Dyer (1925) stated: 

"The variety Stigmatella sessilis crassa is abundant in the Credit Member. 
It is very similar to S.sessilis Cumings and Galloway in internal characters, 
but differs decidedly in manner of growth. The variety forms coarse irregu- 
lar zoaria, tightly adhering to the fragments of other fossils, chiefly the 
trilobite Isotelus. In some parts, the zoarium is as thin as two millimetres, 
but in other parts it is very coarse, approaching 20 mm in thickness." 
Armstrong's (1945) description was: 

"Zoarium tightly encrusts fragment of Isotelus to thickness of 20 mm. 
Thin sections show very close affinities with S. halysa [S.catenulata var. b]. 
In tangential section zooecia are thin-walled, subpolygonal to subcircular; 
10 or 12 in 2 mm; acanthopores both in angles of junction and inflecting 
walls of zooecia; mesopores few in number. Vertical sections are identical 
to S. halysa except for less numerous acanthopores." 

Emended description 

EXTERNAL FEATURES — Zoarium cncrusts pygidium of trilobite Isotelus, 
thickness 2-15 mm, from which branches arise. Surface not observed, but 
groups of zooecia present in thin sections. 

TANGENTIAL SECTION — Zooccial apcrturcs angular at depth and thin-walled, 
subangular to subcircular near zoarial surface where wall thickens, mostly 
8-11 zooecia in 2 mm (Table 1); in deep section zooecial walls 0.01 (or 
less) to 0.02 mm thick, increasing to 0.06 mm near surface; wall con- 
centrically laminated. Mesopores few to relatively numerous (Table 1), 
triangular to quadrangular, often in pairs, Acanthopores moderately 
abundant (Table 1, 17-34 in 1 mm^), occasionally slightly inflecting, 0.02- 
0.06 mm in diameter, with central lumen encompassed by dense concentric 
laminae. Zooecia in groups (monticules/maculae), larger than in interven- 
ing areas (Table 1 ). 

LONGITUDINAL SECTION — Zooccia subprostratc for short distance, then 
sweeping in a broad curve to open slightly obliquely at surface; walls mostly 
straight, locally undulating or crenulate, monilae at intervals, developing at 
same level throughout section, tenuous in axial zone, thickening two-fold or 
more in mature zone; wall laminae convex outward, diverging from clear 
median band at moderately low angle and passing into diaphragms. Dia- 
phragms horizontal, widely spaced, commonly two or three in a single 
growth period. Chainlike mesopores, mostly in single or double files. 
Acanthopores present throughout the section, from central lumen laminae 
diverging outward at moderately low angle and passing into diaphragms. 
REMARKS — S. halysa crassa (= S.sessilis crassa Dyer) differs from S.sessilis, 
a discoidal form from the Maysville, Cut 7 on the Big Four Railroad, near 
Manchester Station, Indiana, in the shape of zoarium, fewer diaphragms, 

10 



more numerous mesopores, and locally inflecting acanthopores. In addition 
to the holotype three fragmentary, poorly preserved topotypes occur in the 
collection. This variety probably represents a new species but until more 
material is found the present designation is retained. S.catenulata var. a and 
S.halysa are also related. The three forms were compared quantitatively 
in pairs, and significant differences are expressed in Table 1 . 
LOCALITY — Dundas Formation, Credit Member, Upper Ordovician, Erin- 
dale, Ontario. 
TYPES — Holotype ROM 1292hr; topotypes ROM 1321hr, 1322hr, 1323hr. 

Stigmatella halysa erindalensis Armstrong, 1945 

(Fig.3A-c) 

Stigmatella halysa erindalensis Armstrong, 1945, p. 154, text-figs. 8, 9. 

Armstrong's description follows : 

"Zoarium encrusts fragment of pelecypod shell to thickness of 5 mm and 
gives off two branches; surface smooth; no evidence of maculae or mon- 
ticules. In tangential section zooecia moderately thick-walled, rounded to 
subcircular; somewhat smaller than in S.halysa, 11 or 12 in mm; acan- 
thopores and mesopores few and scattered. In vertical section zooecia show 
thin, straight walls; diaphragms numerous due to close succession of growth 
stages indicated by slight increase in thickness of walls and presence of 
acanthopores." 

Emended description 

EXTERNAL FEATURES — Zoarium a small, sheet-like growth upon fragment 
of a-mamelose stromatoporoid, a maximum thickness 3 mm; from the en- 
crustation arise branches 4-6 mm in diameter, only bases preserved. Surface 
with small, low monticules, 2-2.5 mm apart when measured from centre to 
centre. 

TANGENTIAL SECTION — Zooccia angular in deep sections where wall thin, 
subangular to subcircular toward periphery where wall thickens appreciably, 
commonly 11 zooecia, rarely 12 in 2 mm in intermonticular space (Table 
2); zooecial walls in deep sections mostly 0.01 mm thick, 0.02-0.04 mm 
thick near surface, to 0.05 mm thick in monticules, wall concentrically 
laminated with central, light-coloured band or black line of demarcation. 
Mesopores few to moderately numerous in intermonticular space (Table 2). 
Acanthopores numerous (Table 2), 0.02-0.05 mm in diameter, seven to 
nine common where four zooecia in conjunction, five to six at junction of 
three adjacent zooecia, lumen small, surrounded by dense concentric 
laminae. Zooecia in monticules few and larger than those in intermonticular 
space (Table 2). 

LONGITUDINAL SECTION — Initial zooecia cither prostrate or curved, then up- 
right, cutting zoarial surface slightly obliquely; zooecial walls thin, mostly 
straight in axial zone, thickening abruptly from base of mature zone through 
which they become monoliform or, in places, crcnulatc, wall laminae convex 
outward, diverging from median band at moderately low angle and passing 

11 




Fig. 3 — Stigmatella halysa erindalensis Armstrong, holotype ROM 12244. A. 
Longitudinal section, x30; B. Longitudinal section, x60; C. Tangential section, 
X30. Stigmatella halysa crassa Dyer, holotype ROM 1292hr. D. Tangential 
section, x30. 



12 



into diaphragms; diaphragms mostly horizontal, spaced apart one, two, to 
three tube diameters. Mesopores few, chain-like. Acanthopores prominent 
particularly in peripheral region, composed of laminae convex outward and 
diverging from relatively narrow central band at moderately low angle. In 
both tangential and longitudinal sections structures reaching 1 mm in 
diameter represent sections through mamelons on surface of host. 
REMARKS — Armstrong based his description of the variety S.halysa erin- 
dalensis on a single example that was found among specimens identified as 
S.lambtonensis Parks and Dyer (1922), now Dekayia lambtonensis (Parks 
and Dyer). S.halysa erindalensis, from the Meaford Formation, and 
S.halysa, from the Dundas Formation, are similar in habit of growth, but 
S.halysa erindalensis is smaller and more delicate. In the latter zooecia are 
smaller, acanthopores fewer, and the zooecial apertures in the monticules 
and intermonticular areas are fewer. The two are compared in Table 2. Sig- 
nificant differences are shown in the number of zooecia in 2 mm in the inter- 
monticular-intermacular areas and in the maximum apertural diameter of 
the zooecia in both the monticules or maculae and in the intervening areas. 
In my opinion S. halysa erindalensis warrants specific rank, but, until addi- 
tional specimens are found, the present designation is retained. 
LOCALITY — Meaford Formation, Erindale Member, Streetsville, Ontario. 
TYPE — Holotype rom 12244. 



Stigmatella crenulata Ulrich and Bassler, 1904 

(Fig. 4a, c) 

Stigmatella crenulata Ulrich and Bassler, 1904, p. 34, pi. 9, figs, 1-4; pi. 14, 
figs. 1,2. 

Stigmatella crenulata Dyer, 1925, p. 54, pi. 4, fig. 6; pi. 7, fig. 8. 
Stigmatella crenulata Armstrong, 1945, p. 151, figs. 1 and 2. 

This species was originally described from the lower Richmond Forma- 
tions, Butler County, Ohio, and the types are in the United States National 
Museum (usnm 43197-43199). 
Ulrich and Bassler's description of S. crenulata follows: 

"Zoarium composed of cylindrical, subcylindrical or compressed, fre- 
quently dividing stems 10 mm in diameter, arising from a broad base and 
forming a clump probably seldom more than 50 mm high. Surface even, 
but in well preserved mature specimens spinulose because of the many 
acanthopores. Maculae well marked, generally composed of mesopores 
which make up the characteristic 'spots' but sometimes formed exclusively 
of zooecia larger than the ordinary. Zooecial apertures small, about 9 in 
2 mm with their walls thin and often beautifully inflected by the numerous 
small acanthopores. Mesopores present, variable in number but usually few 
and mostly aggregated in the maculae. In the axial region the zooecial tubes 
have thin, finely crcnulated walls, and occasionally a diaphragm or two. In 
the mature region the walls increase slightly in thickness, mesopores and 
acanthopores develop, and thin diaphragms cross the zooecial tubes and 
mesopores at varying though always comparatively remote intervals." 

13 



Parks and Dyer (1922, p. 12) stated that the older Dundas strata on the 
Humber River yielded many examples of this species. Armstrong (1945, 
p. 151, 152) noted that the Humber species so designated was actually 
Stigmatella vulgaris Parks and Dyer, the most common Dundas Stigmatella, 
a statement that I believe to be correct. But S.crenulata occurs in the Erin- 
dale member of the Meaford Formation, as pointed out by Dyer (1925, 
p. 54) and Armstrong (1945, p. 151). Dyer's type is here described in 
detail for the first time. 

Description 

EXTERNAL FEATURES — Zoarium fragmentary, a clump-like growth sus- 
pected, with branches to 10 mm in diameter; surface with maculae com- 
posed of larger zooecia than those in intermacular areas. 
TANGENTIAL SECTION — Zooccial apcrturcs angular in deep sections where 
wall thin, commonly subangular to subcircular near surface where wall some- 
what thicker, apertures faintly petaloid owing to inflecting acanthopores; 
zooecia 9-10 in 2 mm in intermacular area (Table 3), walls 0.01 mm thick 
in deep section, 0.02 mm near surface, in maculae 0.03-0.06 mm thick; wall 
concentrically laminated with central, light-coloured band where wall is 
thick, dark line of demarcation where wall is thin. Small, angular mesopores 
(Table 3) varying in size, more numerous in maculae where they are com- 
monly centrally located. Acanthopores abundant (Table 3), moderately 
inflecting, 0.01-0.06 mm in diameter, having small lumen surrounded by 
dense, concentric laminae, four to six occurring at junction of three adjacent 
zooecia, situated in angle of zooecia as well as in zooecial walls. Zooecia in 
maculae larger than those in intermacular area (Table 3). 
LONGITUDINAL SECTION — Zooecia curve broadly from axial zone and open 
slightly obliquely to surface; walls at first thin and undulating, then finely 
crenulated, with periodic moniliform thickenings, wall laminae sharply con- 
vex outward, diverging from line of demarcation at moderately low angle 
and passing into diaphragms. Diaphragms rare, mostly horizontal, two 
usually occur in each periodic growth. Mesopores few. Acanthopores com- 
mon in peripheral zone, rarer in axial zone, wall similar to that of zooecia. 
REMARKS — While studying this specimen I also examined three thin sections 
of syntypes (usnm 43197, two sections; usnm 43198, one section) of 
S.crenulata. So similar in all morphological details are these sections that I 
have no hesitation in referring the rom specimen to that species. 
LOCALITY — Meaford Formation, Upper Ordovician, Streetsville, Ontario. 
TYPE — Hypotype ROM 12297. 

Stigmatella hybrida Dyer, 1925 

(Fig. 4b, d) 

Stigmatella hybrida Dyer, 1925, p. 71, pi. iv, figs. 7, 8; pi. vii, fig. 1. 

Original description by Dyer, 1925: 

"A bryozoan, which differs from any previously described species, was 
found in the Strophomena varsensis zone of the Streetsville member at 

14 





."Sc^^^'.V 



K • 



*-. 



% 



■ V 



41 ■> 






Fig. 4—StigmateUa crenulata Ulrich and Bassler, hypotype ROM 12297. A. Tan- 
gential section, X30; C. Longitudinal section, X30. Stigmatella hybrida Dyer, 
holotype rom 12170. B. Tangential section, x30; D. Longitudinal section, X30. 

75 



Cooksville Creek. The zoarium consists of a large, more or less cone-shaped 
mass, measuring 40-45 mm in diameter, with smooth surface, there being 
no evidence of either maculae or monticules. 

"In tangential sections, the typical appearance of S.crenulata, Ulrich and 
Bassler, is presented. Zooecial tubes are of medium size. The acanthopores, 
which are numerous, are found between the junction angles of the walls of 
the zooecia and strongly inflect the walls. The mesopores are gathered into 
maculae. 

"The features of the aspects as shown by vertical sections, differ decidedly 
from those of S.crenulata and suggest S.catenulata, Cumings and Galloway. 
The zooecial walls are not crenulated as in the former species but are straight 
as in the latter. There is also a marked development of chain-like mesopores 
as in S. catenulata. 

''S.hybrida is one of the best defined species of the genus Stigmatella. It 
differs quite strongly in growth and in the combination of characters as seen 
in sections from any other form in the Cincinnatian series." 

Emended description 

EXTERNAL FEATURES — Zoarium cncrusts a hemispherical, mamelose 
stromatoporoid upon which two Bryozoa, other than Stigmatella, also grew. 
S.hybrida represented by three recurrent growths, interrupted periodically 
by the associated species. Diameter of entire assemblage, originally con- 
sidered to represent S.hybrida only, approximately 65 mm, height 35 mm. 
Final growth of S.hybrida 10 mm thick. Surface with tiny, pointed mon- 
ticules, 1-2 mm apart, composed of zooecia larger than those in intermon- 
ticular areas and displaying clusters of mesopores. An irregular tuberosity, 
with basal diameter of 20 mm, extends 1 5 mm from surface and terminates 
in a rounded extremity with shallow, central concavity; bases of similar, 
smaller outgrowths, also present. 

TANGENTIAL SECTION — Zooecia angular with thin walls in deep sections, 
angular to subangular nearer periphery, 10-12 zooecia in 2 mm (Table 4), 
walls 0.01-0.02 mm thick at depth, 0.03-0.05 mm in peripheral region, 
slightly thicker in monticules, composed of concentric laminae, median 
light-coloured area where wall is thick, dark line of demarcation where wall 
is thin. Acanthopores numerous (Table 4), inflecting, commonly rendering 
zooecial apertures subpetaloid, seven to 10 normally at junction of three 
adjacent zooecia, situated in zooecial angles, also in zooecial walls, diameter 
0.01-0.04 mm, central lumen surrounded by dense concentric laminae. 
Mesopores angular to round (Table 4), mostly clustered in monticules. 
Zooecia in monticules larger than those in intermonticular areas (Table 4). 
LONGITUDINAL SECTION — Zooccia arise from base in either subprostrate or 
semi-upright manner, then become straight to zoarial surface, intersecting it 
nearly at right angles; zooecial walls mostly straight in axial zone, with 
monilae and some crenulation in subperipheral zone, traceable at same 
horizon throughout sections; wall thickening gradually through initial part 
of peripheral region, uniform thickness maintained thereafter; wall with 
laminae convex outward, diverging at low angle from demarcation line and 

16 



passing into diaphragms. Diaphragms usually horizontal, rare in axial 
region, in peripheral zone two to three present. Mesopores chainlike but 
rare. Acanthopores best observed in peripheral area, their central lumen 
flanked by diverging laminae as those in zooecial walls. Circular structures, 
diameter 1-2 mm, represent mamelons of the stromatoporoid host. 
REMARKS — This spccics is one of the most easily recognized in the collection. 
S.halysa erindalensis is similar to S.hybrida in zoarial growth and host pref- 
erence, but when compared quantitatively the two species differ significantly 
— number of zooecia in 1 mm^ fewer, acanthopores in 1 mm- in intermon- 
ticular areas more numerous, diameter zooecial apertures in both monticules 
and the intermonticular areas greater (Table 4). 

LOCALITY — Meaford Formation, Upper Ordovician, Cooksville Creek, 
Ontario. 
TYPE — Holotype ROM 12170. 



Stigmatella per sonata lobata Dyer, 1925 

(Fig. 5a-c) 

Stigmatella personata Ulrich and Bassler, 1904, p. 35, pi. 12, figs. 1-3. 
Stigmatella personata lobata Dyer, 1925, p. 72, pi. 6, fig. 1. 

Original description of S. personata by Ulrich and Bassler follows : 

"This is one of the non-mesopored species of the genus and forms smooth, 
branching zoaria very much like S.crenulata and S.spinosa. From the former 
it is distinguished by having fewer acanthopores, no mesopores and in lack- 
ing the crenulation of the walls in the immature region. From S.spinosa it is 
separated by its larger zooecia, 7 to 8 being found in 2 mm while 10 are 
required in that species to cover an equal distance. The acanthopores in 
S. personata also afford a difference, being but seldom more numerous than 
the junction angles, which they usually occupy. In S.spinosa, it will be re- 
membered, they are so abundant that they almost completely surround the 
zooecium." 
Dyer's description of 1925 was: 

"A new variety of this species was found among the older collections of 
fossils at the University. The exact horizon of which is not known. 

''S. personata lobata differs from the type species (Ulrich and Bassler 
1904) in the manner of growth and in the character of the surface; it forms 
an irregular, lobate mass 30 mm in diameter, with the surface covered by low 
but conspicuous monticules composed of tubes which are slightly greater in 
size than the average." 

Emended description 

EXTERNAL FEATURES — The single zoarial fragment, 30 x 25 X 20 mm, 
overgrows a crinoid stem. Projecting about 5 mm from surface are several 
small rounded protuberances suggesting dwarfed branches, terminal diam- 
eters of which range from 6-15 mm. Surface with slightly elevated, rounded 
monticules spaced 2 to 3.5-4 mm apart when measured from centre to 

17 



centre, composed of larger zooecia and more numerous mesopores than 
those in intermonticular areas. 

TANGENTIAL SECTION — Zooecial apcrturcs angular in deep sections where 
wall is thin, subangular or subcircular in sections near the zoarial surface 
where wall moderately thick, slightly inflected by acanthopores in places, 
normally 9-12 zooecia in 2 mm in intermonticular areas (Table 5), larger in 
monticules; zooecial walls 0.01 (or less) to 0.02 mm thick in deep sections, 
0.03-0.04 mm in sections near surface, to 0.05-0.06 mm in monticules, 
wall concentrically laminated. Mesopores few, small, angular to circular, 
occurring in monticules, normally scarce in the intermonticular areas (Table 
5). Acanthopores moderately abundant (Table 5), commonly located at 
junction of adjacent zooecia, in places inflecting, range in diameter 0.01- 
0.06 mm, generally 0.02-0.05 mm, small round central lumen surrounded 
by dense concentric laminae. Zooecia in monticules larger than those in 
intermonticular space (Table 5). 

LONGITUDINAL SECTION — Attitude of earliest part of zooecia not observed, 
but later zooecia curve out broadly, then turn laterally to reach zoarial 
surface slightly obliquely, Zooecial walls predominately straight, thin 
throughout axial region, thickening gradually to base of peripheral zone 
where wall generally uneven and crenulated, monilae present, often trace- 
able horizontally over a considerable portion of sections; wall laminae con- 
vex outward, diverging from median line at relatively low angle, then passing 
into diaphragms. Diaphragms horizontal, oblique, or curved in mature zone, 
where two to four occur spaced apart from one to three zooecial diameters, 
their apparent absence in axial region possibly because of extreme tenuity. 
Typical mesopores not observed. Acanthopores conspicuous in peripheral 
sections but not restricted to that zone. 

REMARKS — Dyer (1925) based his description on the single zoarial frag- 
ment that is assumed to have been recovered from some unknown horizon 
within the Meaford Formation. Utgaard and Perry (1964), without examin- 
ing the type of Stigmatella personata lobata, stated that the lobate zoarium 
and more prominent monticules are mere variations in growth form; hence 
they regarded the variety as a synonym of S. personata Ulrich and Bassler, 
Richmond, Hanover, Ohio (usnm 43201). The lobate zoarium, with 
prominent monticules, distinguishes this variety externally from S. personata. 
Although these features may be merely an expression of the environment, a 
significant difference occurs in the number of entire acanthopores in 1 mm^ 
(Table 5). I do not consider this form to be synonymous with S. personata 
but hesitate to create a new species on the evidence afforded by one specimen. 
LOCALITY — ?Meaford Formation, Upper Ordovician, Streetsville, Ontario. 
TYPE — Holotype rom 12171. 



18 




Fig. 5 — Stigmatella personata lohata Dyer, holotype ROM 12171. A. Longitudinal 
section, X30; B. Tangential section, x30; C. Tangential section, x30. 



19 



Stigmatella vulgaris Parks and Dyer, 1922 

(Fig. 6a-c) 

Stigmatella vulgaris Parks and Dyer, 1922, p. 15, pi. 1, figs. 13, 14; pi. 6, 

fig. 12. 

Stigmatella vulgaris monticulata Armstrong, 1945, pi. 155, 156, text-fig. 11. 

Original description of Parks and Dyer: 

"In the Don Valley brickyard one of the common fossils is the 'puff-ball'. 
This seems to be a variable species of Stigmatella of which the zoarium is of 
considerable size, massive, nodose, subhemispherical, or even thick discoidal 
in shape. The appearance of the specimen which is selected as a type is 
indicated in Plate vi. Figure 12. This specimen measures 80 mm X 55 mm X 
30 mm. Other examples, of a roughly hemispherical shape, frequently 
measure 50 mm in width and 20 or 25 mm in height. While it is quite possible 
that more than one variety or even species is represented by the various 
specimens, we have not been able to recognize constant features by means of 
which they can be differentiated. 

"The surface of the type is smooth, and maculae are indicated only by 
clusters of larger cells very indistinctly developed at intervals. Tangential 
sections very near the surface (Plate i. Fig. 13) show zooecia of very irregu- 
lar shape and size with thick walls and numerous large acanthopores. We are 
inclined to regard the smaller cells as young zooecia rather than as meso- 
pores. In places, the cells are somewhat larger but no other difference is 
observed. Deep tangential sections are strikingly different: the same ir- 
regular character of the tubes is seen, but the walls are extremely thin and 
the acanthopores less numerous and very small (Plate i. Fig. 14). 

"Vertical sections show very thin-walled zooecia crossed by a few distinct 
diaphragms chiefly in the peripheral zone. No structures which can be inter- 
preted as distinct mesopores are seen. In places the walls are crenulated and 
in others quite straight. The structure is intermediate between that of Stig- 
matella crenulata and S. personata. 

"The hemispherical examples of this species show no difference in vertical 
sections, but tangential sections are almost devoid of acanthopores and 
groups of larger cells are more distinctly developed; in some cases very large 
zooecia appear among the smaller ones. In one case the surface is distinctly 
monticulose but the sections do not differ in any distinct manner." 

A variety described by Armstrong (1945 ) , S. vulgaris monticulata, is now 
considered to be synonymous with S. vulgaris (Table 6). 
Armstrong's description of S. vulgaris monticulata follows : 

"Surface of zoarium covered with slightly raised monticules; in some 
monticules 2 mm in diameter occur at intervals of 3 mm; in others, they are 
larger, 3 mm in diameter, but spaced at 2 mm intervals. Internal structure 
identical with that of S. vulgaris; in tangential section with 6 or 7 larger 
zooecia in 2 mm, and 10 smaller tubes in 2 mm." 



Emended description 

EXTERNAL FEATURES — Zoarium of holotypc massive, irregular in shape, 



20 














: .V 






^"^ 



\ 



Fig. 6 — Stigmatella vulgaris Parks and Dyer, holotype rom 1091hr, hypotype 
ROM 1516HR. A. Longitudinal section (rom 1516hr) x30; B. Tangential section 
(ROM I516HR) X 30; C. Tangential section (rom 1091hr) x30. 

21 



dimensions 80 X 55 x 30 mm, with lobate extensions, growth beginning on 
crinoid stem. Surface with low rounded monticules, 2.5-3.5 mm apart when 
measured from centre to centre, eroded portions of surface appear maculate. 
Hypotype (S. vulgaris monticulata Armstrong) a lobate mass, 80 X 60 X 40 
mm, with embedded crinoid stem. Monticules better preserved than in holo- 
type, although obliterated by weathering in certain areas. Zooecia in mon- 
ticules larger than in intermonticular space. 

TANGENTIAL SECTION — Zooccia angular with thin walls in deep sections, 
subangular in sections near surface where wall thickens appreciably, 7-9 
zooecia in 2 mm (Table 6), larger in monticules; zooecial walls 0.01 (or 
less) to 0.02 mm thick in deep sections, 0.03-0.04 mm near surface to 0.05 
mm in monticules, concentrically laminated, where the wall shows ring of 
light-coloured laminae, where thin dense line of demarcation is present. 
Typical mesopores few (Table 6). Acanthopores numerous (Table 6), 
noninflecting, 8-10 at junction of four adjacent zooecia, seven to eight 
where three adjoin, diameter 0.02-0.04 mm, central lumen surrounded by 
dense, concentric laminae. Zooecia in monticules larger than those in inter- 
monticular space (Table 6) . 

LONGITUDINAL SECTION — Zooccia at first curve broadly, then straighten to 
open nearly at right angles to surface, wall intermittently crenulated and 
straight in successive axial and peripheral zones, respectively, thin axially, 
moderately thick toward periphery, monilae few; wall laminae convex out- 
ward, diverging from central band at moderately low angle and continuing 
into diaphragms. Diaphragms horizontal, concave, diagonal, one or two 
widely spaced in axial region, commonly two or three in peripheral zone 
about two to three tube diameters apart. Mesopores not recognized. Struc- 
ture of acanthopores most characteristic of peripheral zone, similar to that of 
zooecial walls. 

REMARKS — Although Only the types of S. vulgaris are here described, I 
examined many examples of this common Dundas species and found that 
the massive, irregularly shaped zoarium is invariably associated with a 
crinoid stem and that the microscopic detail is strikingly similar. The state- 
ment by Parks and Dyer (1922) that S. vulgaris is intermediate between 
S.crenulata and S.personata has little merit. S.personata and S. vulgaris are 
significantly different in: 1) number of entire mesopores in 1 mm^ in inter- 
monticular or intermacular areas: 2) in measurements of the apertural dia- 
meter of the zooecia in intermonticular or intermacular areas; and 3) in 
measurements of the apertural diameter of the zooecia in monticules or 
maculae (Table 7). 

S. crenulata and S. vulgaris differ significantly in all the comparative data 
except the measurements of the maximum apertural diameter of the zooecia 
in the monticules or maculae (Table 3), 

LOCALITY — Dundas Formation, Upper Ordovician, quarry Toronto Brick 
Company (formerly Don Valley Brickyard), Toronto, Ontario; Humber 
River, Toronto, Ontario. 
TYPES — Holotype ROM 1091HR, hypotype ROM 1516hr. 



22 



Acknowledgments 

Thanks are expressed to Mr. John Monteith, Curatorial Assistant, Depart- 
ment of Invertebrate Palaeontology, for the skilful restoration of original thin 
sections and for his expert preparation of new sections essential to the study, 
Mr. L. M. Kisko, Department of Zoology, University of Toronto, for his 
generous assistance with statistical data, and Miss Joan Burke, Secretary of 
the Department of Invertebrate Palaeontology, rom, for her careful typing of 
the manuscript. I am grateful to J. E. Merida of the Division of Invertebrate 
Paleontology, United States National Museum, for the loan of types of 
Stigmatella crenulata. To Professor T. G. Perry, Department of Geology, 
Indiana University, Bloomington, Indiana, Dr. T. E. Bolton, Geological 
Survey of Canada, Ottawa, Dr. J. Utgaard, Department of Geology, South- 
ern Illinois University, Carbondale, Illinois, and Dr. June Phillips Ross, 
Western Washington State College, Bellingham, Washington, who kindly 
read the manuscript, I wish to express sincere appreciation. The photo- 
micrographs were taken by Mr. Brian O'Donovan, Department of Geology, 
University of Toronto. 



23 



a 




>i 




tn 




« 




&^ 




O 




Q 




tn 




-b 




~-»< 




53 




-« 




to 




-a 




c 




<n 




0S 








O 




o. 


tA 


■«-> 

o 




'o 


S 


r-* 




r^^ 








<*H 




o 


s 


C/3 




c 


c 


_o 


"^ 


'■*-> 


d 


o 


5* 


o 


> 


(A 


'Eh 


o 




^ 


^ 


■(-J 


c3 


/•—v 


Vi 


P3 


C 


u 


(U 


c3 
> 


s 


s 


3 


Q 


C/3 


"i: 


ctJ 


as 


(U 


§ 


s 


■hM 




Q 




o 


t/5 



Co (U 



Co 00 



GO 



o 

XI 



D 



O <U 

o o 



1) Ah 
(U O 

p. o 



?" II 

o 
c 
o 



a 

6 

o 
U 



O 



c 

as 
o 

'c 



CO 



> 



OS 
C 



C/2 



-3 



O 

c 
o 

"S 
.£? 

CO 



CO 



Co 



>z. 


c3 


f-i 


> 


U( 


a 


o 


-2 






T5 


5u 




5 


03 


Co 


-t-t 


^ 


00 


II 


Q 




>1 


u 


?s 


CO 





Co 



Co 



Q 

CO 



+1 Vh 

IX ■>< 



Q 

CO 



CO c 
+1 u, 

IX ">< 
W 



CO 



03 
> 






Q 




c« 


a 


w 


a 


3 


CO 


§ 


+1 






IX 





<N 

O 



O 

o 



SQ U O 

OC CO "^ <^. «^ <^ 






CO 



CO 



d -^ 

+17 

oo oo 

ON 






On 



d O 

+17 
(N 00 









d ^ 

+17 

<N OO 






C 03 



a 




e 


OJ 

s 


<N 


;-i 




(U 


_c 


-4-> 




c 






OS 






Ui 


'o 


O 


<u 




o 


Ui 


o 


J2 


N 


"B 


U-. 


,o 


o 


*-(-> 


U( 


c 


d) 


o 


B 





(N OO (N 

"^ o?J OO 0^ <^ 

d < d M r^" 






d ^o 

+17 

ON 



(U 



CO 



CO 

z 












O ^ 

+17 









d ^ 

+17 

ON m 






J. o 

<^ b 

o 3 

(U 2 ^ 

iii £ <u 



Oj 



z .s 



>*^ _- ^H 

'^ .S i2 

^ c ^ 

§ a B 

z - .a 



cy ^ ca r- d^ OS 



OS 
ON 



o o 
o o 



OS 



+17 



O 



o 



ts 









+1 



<N 



O 






^ '^ 

+l7 
^n oo 

• 1—1 
1— i 







o 






fS 


00 


V-i 




<L) 


O 




O 


Ui 




a 


iS 




o 


3 










c 


^4-^ 




03 


C 




o 


o 




03 


a 


C/) 


(U 


Ui 


03 


Vh 


(L) 


<U 


c 


+-1 


03 


(U 




;-! 


f I , 


c 


03 


o 


fS 


3 




a 


o 

03 


a 

-1 


a 


a 




Ui 


T-H 


D 



ro Tj- (VI 

cy u-i cy oo ojj r- 
< '— I ■< <^ pa (N 



m 

O 



O vo 

?i? 

d d 



T^ <y-> ,— I 

o o o 
o o o 



«/^ oo oo 

cy oo d?J iO d<j O 

< -^ < (N qa r- 






o 



o 


r- 




(N 


d 




+1 


i 


m 


OS 


<N 


1-H 



o o 






o 



o 


r- 




(N 


d 




+1 


i 


ir> 


as 


rs) 


T-H 



o o 



z .a .a 





'^ 




CS 


C*-l 


D 


o 


iS 






;_! 


3 


<U 


O 


a 


03 

a 


.2 


V-i 


-3 


O 


, 


^ 


03 

3 


3 


-4-> 




i-H 

a 

03 


G 
O 

a 


a 




3 




a 


2 


X 


<u 


OJ 


o 


s 


o 

N 



o 
d 



o 
d 
+1 



o o 



vo 



s 



O ON 

d ^• 



o o 



o 



O 

d 







o 


ON 

1-H 






d 








+1 


? 






>n 


^ 






T-H 


^^ 






d 


d 






o 








f^ 




«^ 








o 








;h 


o 






1 

.2 


u 

3 






3 


o 






3 


c 






Vh 


o 


00 




3 


a 


OS 




U( 


>H 


Vn 




<SJ 


0) 


OS 




a 

03 


_c 






a 

3 

a 


_c 


3 




2 


03 

a 




'>< 


(U 


Ui 




03 


o 
o 

N 







24 



c 

■l-> 
00 






O 

o 

c 

o 

D 
(/) 

O 



C C 
^ C 

ex c 
>~> a> 

o.> 

o ^ 



•5 S 






I>1 

.s: 



<3 
to 



Co 



a 

B 
o 
U 

w 

PQ 
< 



cd 

o 



00 



C/5 



03 

c 

03 



00 

c 
o 



> 



OS 

C 
03 



GO 



a 



o 

C3 
03 
o 

"c 



CO 



Q 

00 



00 c 



K 
^ 

-§ 

e 



to 
-^ 

-a: 
Co 



Q 



+ 1 l-H 

w 



o 
o 



o 



00 






00 



o 
o 



— 1 ^ 



-H rj- 



O 
O 



O 

o 



in 






(N 



O 



O 






XI- 



O r^ O On 

ooo^o^o-o- 

+17+17+17+1^+1? 

• ^ (N -H ^H ^H 

On O ^ .... 

^ <N 0000 



(N 


(N 





(N 





(N 


(N 


rs| 


(N 


(^ 






r- 

^ 



o 






o 
d 



>sO "^ 00 -H 

>y^ ON O t~~ O "^ 

0<NOVOO^O -O 

+1 7 +1 7 +1 7 +1 ? +1 

. ^H • ^H • ^H ^-< ^H 1— I 1— I 

r-i O OS • ■ • _■ 

— ( ^ -H 0000 



00 

o 



o 

I 



00 



o 






O 
en 



O 



c 




.S 




B 




03 




.2 





S 




















s 




B 


1/2 


■5 
(L> 




'3 


C/3 








03 










03 






s 


03 








N 






N 


2^ 

03 


_c 




_c 


(75 



i2 












s 




c« 


03 





3 






S-i 

1) 


3 




a 



3 


a 





03 
S 

U4 


4> 

2 




-t-> 

E 

.2 


cd 
E 


.2 


C/5 




03 

E 


c 

03 

03 




'-3 


3 


3 


(L) 

*-> 


"o 


03 


(U 


-(-> 


(U 





3 





3 





<D 


<U 


_V-i 


c 


_tH 






o3 










03 


c 


Vh 


C 


i2 


Cl 
03 


£ 


03 




N 









0) 







3 





3 


3 


03 
B 




u, 
<u 
X 

S 

3 


J3 

c 





X 

e 

3 


c 



3 

E 

'>< 

03 


c 



E 

3 

E 
'x 

cd 


c 


E 

••-1 


z 


_C 


Z 


B Z 


_c 


S 


£ 2 


_C 



25 



c 

T3 

3 
-(— > 

in 



-4— > 

o 
'o 



c 

■*-> 

<u 

1/3 

o 

II 

^1 

^ > 

O cd 

5- ^ 
^~» ■*-> 

o a 

o (U 
(U '^ 

C/3 l<!5 



"4; 



S 
o 
U 



X) 
O 



c 
o 

"S 
GO 



00 



T3 

C 



c 
o 



> 

T3 



C 



Q 
oo 



o 

c 

OS 
o 

'S 
c/5 



to 






00 c 

+1 »-i 

w 



to 



Q 

00 



00 c 
+1 i3 

IX ^ 



-H m ^^ 

o o o 
o o o 



oo s 
V V 







(N 


O 


oo 


<N 


(N 


•T) 


T— 1 


m 



r<^ oo 



O -H 



0^ 



O 



O 



+1 



o\ 



+1 



Tl- ^ ^ 

r- o ON o OS 

O On O • O 



+1 7 +1 Y +1 ? 

osr^voT— ir~~ONm(N(NTi- 

• -^ • rs| • ^ 

r- T-H (N o • o • 

(N o o 



o 



O 



O 



oo 



O 






O 



O 



O 



O 



O -H 



OS "-H 



OS ^ -H 



^^ O 00 O <^ 

O O O ^ oo O • O 

+17+1^ +1 ^' +1 ? +1 <? 

r^ON^^^O'— lunOoo-^ 

• (N (N (N ^ ^ 

OS CnI O .... 

m O O O O 



O 



O 



O 



O 



O 







4> 
















3 




c 




_c 












o 












_c 




,c 




o 




_c 




g 




.2 




cd 




g 




a 




g 


C/3 








C/3 


bH 








03 


o 




o 


03 






s 


C/5 




(U 
03 


o 

N 




O 

N 


03 


s 

cd 




00 


03 
03 


1/3 

o 


3 


o 




o 

t-H 


3 




O 

a 
o 

C/3 

g 


o 

03 
g 


O 
X 
■(-> 

c 

03 

o 

03 


o 

03 
g 


g 

.2 

13 


3 


4> 
g 

3 
3 


o 

03 

g 




CO 




(U 




Ui 


U( 


ui 


h^ 


"5 


03 


a> 




?^ 


O 


3 


O 


3 


o 


(U 


4> 


_tH 


c 


U( 






03 






o 
o 


03 


'■(-> 

c 


Ui 


C 




a 

03 


g 


a 

C3 


J2 


N 

^4— 


i3 




O 

3 




3 


o 


3 


o 

X) 


3 

o 

03 
g 


o 

X 


o 

X 


o 

g 

4^ 


g 

3 
g 


3 


g 

3 
g 


c 
o 

g 

<L) 

■*-> 


3 


g 

3 


c 
o 


g 

3 


03 


c 
o 


03 


;z 


_c 


Z 


g Z 


H 


S 


g s 


C 



26 



c 

-t-> 
00 



"o 

42 



:s ^ 

*.§ 

C C 

.^ c 
>;> bo 

O 0) 

o c 

O ;3 

(U ^ 






to 



'4> 



B 
o 
U 



o 



c 
o 

'5 

GO 



zn 



c3 
T3 

c 



W 

GO 

c 
o 



> 






00 



o 

c 

o 



to 



Q 

CO 



00 c 

+1 I-H 

w 



03 
K 
-Si 



to 
to 



Q 
00 



+1 i; 



00 

z 



o 
o 






rsi 



o 
o 



O CnI 

o o 






OS 



IT) 
>0 



On 00 

^H O 



O 



O 



(N 



o 






O 



O On O O 
• <N • (N 

0^0 • O • 

+1 7 +1 ? +1 7 

• <N <N (N ^^ ^M 
C\ .... 

(N 0000 



O <N O 

+17+17 



(N 


<N 


vo 


V£) 


^ 


(N 


<N 


(N 


rsi 


CN 



^ 
^ 



00 



00 
O 






o 



On 



O 



o 
d 



O r~~ o «o 

0(N0^0^0 -O • 
+17+17+17+17+17 

T— ior~"^T— lOONOf*^'— I 

. T— I • • ^^ T— I 1—1 1—1 1—1 

^H O OS ' ' ' ^* 

T— I T-l rH 0000 



O 






O 

CO 



O 



a 






c/3 D 



^ c/, .is c^ 



a> 1/5 



o 

G, 
O 

(U 



O 

o 

3 :S 



a 









03 -H S 



^ (U o 3 



,,_, .-H ,,_, 



3 

^ »-, 

o3 (U 

S -a 

B 3 



o S o 



3 "-I 

c S 

O 3 



03 <U 

il 

.s2 



2 3 o 

(U Oj 

ii a "-5 

•B.g a 
§ ^S 
a s .a 



27 



>» 








t 








4> 








fU 








'd 








c 








ctf 








T3 








u 








a 








a 








(30 








■i-t 








P 








>-( 








a> 








.-4-> 








(4-1 








Rj 








(3 








tx 








Q 








K 




>, 




Q 




•»-> 




S 




^ 




S^ 




X5 




t^H 




a 




Co 









g 




0. 


Q 


C4-I 






>«« 


■t-< 
03 


C/3 


11 




3 


(U 


• #N 


2 




;-i 


-t-> 


<ij 


(/3 


■4-1 


c 

OS 


t^ 


c 

(L) 


B 




S 


CO 


S 








773 


'c 




'o 


s 


.SP 




(U 




'^ 




a 


c 


_c 




tz) 


"^ 






r- 


c 


II 




<N 


(U 






> 


C/2 




s 


*e3) 


z 




Q 


<u 






S; 


i-i 


• »\ 




i 


C/5 









c 






to 


a 


13 






(U 


c3 




^3 


Vh 


T3 




C 

"a? 


3 


C 
03 

-4-> 

II 


2 


0^ 


CO 

■(-J 


u 


2 


'0 




00 




x: 




. r. 







C/5 




,0 


12 


^0 




.2 


Co 




T3 


(L> 







3 


TD 




(/5 


v5 


T3 




<t) 


(4-1 






2i 





•O 






c« 


C 
03 




v-^ 


3 






<3 


V3 






••«- 


<U 


II 




Q 


Vh 




-C) 








^ 
Q 




00 




■kJ 


0^ 


■ r\ 




Q 




(U 




K 




_N 




g 




W3 




|>i 








i. 




D 




^ 








s^ 




"H- 




a 




B 




=s 




a 




^ 




</5 




■♦« 








Q 




II 




S 






•Sf 




Z 




■Ki 








Co 








«4-l 

















c 

















CO 
















'C 








a 








a 








6 

















U 








•n 








w 








_) 








pq 








< 








H 









O 

c 

03 
o 

s 

'c 

CO 



Q 

CO 



CO c 

+ 1 Ui 

IX ">< 



Q 

CO 



CO E 

+1 Si 

IX '>< 

w 



PQ 
< 

> 

< 

O 

< 
< 



O 



o 

<N 



C 



u 
0) 

B 



CO PI CO 

z ^ z 

V 



CO 

z 



o 

ON 



o 



C30 



1-1 (N ^ 



o 
o 



<N 



m 



O 
O 



O 



CO 

O 






O <N O <N 

O -H O (N O • O • 

+1 7 +1 1 +1 7 +1 ^ 

OOOr^(N«r^rNO 






o • o • 
o o 



m 





<N 








"O 


r«-) 


m 


r- 


r- 


<N 


<N 


(N 


(N 


<N 



<N 






O 



O 



^ ^ VO 






O ra O 



00 000^ 
000 • O • 



+1 



+1 ^ +1 



+1 



+1 



^osONOOONrsimfNm 



O ^ 



o 

00 






o 



o • o • 
o o 









ii B 



.« 1^ 



C/2 <U 



(U 03 



O 

a 
o 

C/3 
O 

03 <U 

Ui "^ 

oi ^ 
»-, <l> 
^ «+- 

3 o 

o3 (u 



u a 

03 O 
7\ ■<— ' 



3 i^ 

Ui 03 



•*=• <U O 3 

(-H C '-' *^ 

— — ■ "^ }—i u^ 

03 <U 

il 



.2 
'o 

O 03 
O OJ 



ii 3 

OJ c3 

03 )-i 

03 — £ 
-75 OS 

3 L^ Ld 

03 



3 O 



O W 
o3 O 



3 





C 


B 





3 


B Z 



C ID 03 

3 c § 

c X ^ 



28 



c 



•4—' 



^ • 

Vh > 

'^ "JTri 



Mo 



to 



a 

E 
o 

U 

w 
oa 



o 

G 
OS 

o 
'c 
c75 



a 
o 



c 
o 

"c 

60 



C/2 

Z 



c 



c 
o 



> 



c 



C/5 



Co 



C/5 



■(-> 
W 



!X 



CO 



Q 

(>0 



00 c 
+1 I- 



00 



o 



oo 

z 






00 

z 



oo 

z 



00 

z 






O —1 









O 



O 



VO lO Tj- T-H -H 

O ^ r- O ON O On 

O O O ON o • o • 

+1 <=^ +1 ^ +1 7 +1 ^ +1 7 

osr~-^or-~ONm(N(N"^ 

• ^H • (N • ■^ 

r^ ^ fN O • O • 

<N O O 



o 



^ 

^ 



o 



O 



o 



OO 
ON 



o 



O 



O 



O 



o ^ 



O rn ON ^ -H 

^ <N OO O <N O ON 

o d d '^ d • d "^ 
+1^+1^+17+1^+1^ 
oor-r-~oor--(NO<N-^ 

r- ^ (N d • d • 
(N o o 



OO 






O 
<N 



O 






3 C 



o 

c/0 0) 



— tH £* ^ 



1) 03 



£ 

3 

z 



o 

D. 
O 

00 

<U 

Cd (U 
(U Ui 

^ c 

U (U 

3 o 

S -^ 

^ E 
<u 5 

. S Z 



C3 o 

t- a 

03 o 

3 ^ 



3 ii 
E E 



-H -^ tn 



03 

E 


03 
O 


kH 


03 


(L) 






(U 


C 


^ 


"■^ 


•4.^ 


Ui 


c 


O 


(U 


Lh 


t.— 


iS 


o 


3 




C 


E 


o 


3 


E Z 



.2 

u 

3 



E 

.2 

03 ^ 
"T; OS 



03 <U 



3 O 



3 


03 


c 
o 

E 


E 

3 

£ 


Ui 


">< 


<L) 


03 


_c 


S 



o ^ 
i> E 

.y E 

o <^ 
ES 



29 



'^t 




\o 




ON 




^—1 




r\ 




>> 




u, 




u 




(U 




eu 




73 




C 




<a 




•a 




i-i 




a 




a 




W) 




■(-> 




D 




u 




D 




^4-^ 




tCH 




cd 




<3 




•<-». 




a 




s: 




o 




^ 




\. 




<^ 




^ 




^ 




u 




o 




uz, 


(A 


cd 


S 


•*-> 




OJ 


"S 


Q 


s 


















C/2 

c 


s 


B 


_c 


o 


c 


<L> 


(D 


a 


> 


CAl 


'Sb 


r- 


w 


<N 


2: 


^-^ 


cd 


a 


V3 


•fc- 


-«-> 


s 


c 


s: 


1) 


§ 


S 


:^. 


(L> 


i^i 


;-i 


Cl. 


3 




C/5 


Co 




T3 


S 


cd 






00 


,^^ 


•t-' 


D 


V3 


D, 




>^ 


1 


-t-> 


■fc- 


O 


C/^ 






O 


-(^ 


Xi 


c 




0) 


o 


T3 

3 


C/5 

c 


00 


^O 


«+-( 




o 




on 


1/3 






3 


o 


c/3 


^ 

-(-» 




•S 








SI 




Q 




^ 




s 




a 





Co 

o 

c 
o 

1/5 

a 

S 
o 
U 



o 

c 

o 

*C 
CO 



OJ 

o 



c 
o 

"c 

GO 



CO 

z 



T3 
03 

C 
c3 



U 
CO 

c 
_o 

'> 

T3 



T3 
C 
cd 



Q 
CO 



s: 
Co 



Q 

CO 



CO E 
+1 ^ 



Si 

Co 



Q 

CO 



CO c 
+1 t- 



o 
o 



o 



(N 






3 



3 g 5 g 

V V 



O 



oo 



<N ^ 



O 
O 



O 



p-l 






. 




, 




. 




hJ 


<N 




oo 




o 




o 




ffl 


















< 


















J 


















»— I 


















< 


m 




r<-i 




"-H 




^^ 




> 

< 


"—I 




ir^ 




o 


^^^ 


o 


(N 


d 


^ 


d 


(N 


d 


r*^ 


d 


(N 


O 


+1 


T 


+1 


1 


+1 


d 

1 


+1 


i 


o 


o 


o 


r~- 


(N 


m 


(N 


o 


Z 


(N 




1-H 




d 




d 


. 






<N 






d 




o 


< 


















H 


















< 


















Q 


O 




m 




o 




o 





m oo 



ON 



O 



O 



MD «y-) Tt -H -H 

O -^ r- O ON O On 

• (N • ^ 

o ON o • o 

+1 7 +1 ? +1 ? 

ONr-^^^r-ONf^rNr^rj- 

• ^ • (N • T^ 

(N O • O • 

<N O O 



+1 ^ +17 



o 



O 



O 



O 



Cd (D 





B 
B 




E 


00 










1/3 








cd 










cd 




CO 

cd 
2^ 





2^ 
cd 

jd 



N 








N 



cd 
jd 




00 


cd 





3 


ID 






3 






^ 


a 




cd 


a> 




"S 




cd 





a 



cd 
3 





E 


E 

.2 




E 
.2 


£ 






cd 


c 
cd 

cd 


(U 


3 





3 


•4-> 






B 


_c 


3 


jd 

3 


3 


_c 


c^ 




l> 




^ 


u 


S-( 


u 


cd 


(U 




<u 





3 





3 





m 


_Vh 


c 


_u 






cd 






cd 


c 


Ut 


C 


jd 


a 

cd 


E 


a 
cd 


jd 


jd 






U-4 




3 





3 
^0 


3 


cd 

B 




X) 






ID 

X 


c 


E 


£ 

3 

E 


3 


£ 

3 

£ 


■(-> 
C 


£ 


3 




E 

3 




^4—* 






c 





cd 


c 



X 

cd 


0) 


c 


Z 


E Z 


c 


S 


E S 


_c 



30 



Literature Cited 

ARMSTRONG, H. S. 

1945 Stigmatella in the Ordovician of the central Ontario Basin. J. 
Paleont., vol. 19, no. 2, pp. 149-157. 

BASSLER, R. S. 

1911 The early Paleozoic Bryozoa of the Baltic Provinces. Bull. U.S. 
Natn. Mus., no. 77, pp. 1-382. 

CUMINGS, E. R. AND J. J. GALLOWAY 

1913 The stratigraphy and paleontology of the Tanner's Creek section of 
the Cincinnati Series of Indiana. 37th Rep. Indiana Dep. Geol. Nat. 
Resour., 1912, pp. 353-479. 

DYER, W. S. 

1925 The stratigraphy and paleontology of Toronto and vicinity. Par v. 
The Paleontology of the Credit River Section. Rep. Ont. Dep. Mines, 
vol. 32, pt. 7, 1923, pp. 47-88. 

FRITZ, M. A. 

1970 Redescription of type specimens of the bryozoan Hallopora from 
the Upper Ordovician of Toronto Region, Ontario. Proc. Geol. Ass. 
Can., vol. 21, pp. 15-23. 

1971 The trepostomatous bryozoan Stigmatella catenulata diversa Parks 
and Dyer (1922), a synonym for Mesotrypa diversa (Parks and 
Dyer). Life Sci. Occ. Pap., R. Ont. Mus., no. 18, pp. 1-6. 

LIBERTY, B. A. 

1969 Palaeozoic geology of the Lake Simcoe Area, Ontario. Mem. Geol. 
Surv. Brch. Can., no. 355, pp. 1-201. 

PARKS, W. A. AND W. S. DYER 

1922 The stratigraphy and paleontology of Toronto and vicinity. Part ii. 
The Molluscoidea. Rep. Ont. Dep. Mines, vol. 30, pt. 7, 1921, 
pp. 1-59. 

SIMPSON, G. G., A. ROE AND R. C. LEWONTIN 

1960 Quantitative Zoology. Rev. ed. New York, Harcourt, Brace. 440 pp. 

ULRICH, E. o. 

1882 American Palaeozoic Bryozoa. J. Cincinn. Soc. Nat. Hist., vol. 5, 
no. 3, pp. 121-175,232-257. 

1883 American Palaeozoic Bryozoa. J. Cincinn. Soc. Nat. Hist., vol 6, no. 
2, pp. 148-168. 

1890 Part ii. Palaeontology of Illinois. Section vi. Palaeozoic Bryozoa. In 

Worthen, A. H. Geological Survey of Illinois. Volume 8. Geology 
and Palaeontology. Edited by J. Lindahl. Springfield, 111., Published 
by authority of the Legislature of Illinois, pp. 285-678. 

ULRICH, E. O. AND R. S. BASSLER 

1904 A revision of the Paleozoic Bryozoa. Part ii. On the genera and 
species of Trepostomata. Smithson. Misc. Collns., vol. 47, pp. 15-55. 

UTGAARD, J. AND T. G. PERRY 

1964 Trepostomatous bryozoan fauna of the upper part of the Whitewater 
Formation (Cincinnatian) of eastern Indiana and western Ohio. 
Bull. Indiana Dep. Conserv., Geol. Surv., no. 33, pp. 1-1 I I. 

31 



^: 






'^i^i^A 



'^^l' 






■^3}f 



^ 



r."^: 

,->i.'^ 



'C^.v-, 



4MMM^. 



.A*-' 



•k:'7^A 



\.