PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 699 
tween Toquimia and Aporthophyla have been stated by Ulrich and Cooper (1938, 
p. 182). 
Types—Lectotype : 91595a; paratypes: 91595b-f ; figured hypotypes: 117567a, 
d,e,f,h,j ; unfigured hypotypes: 117567b,c,g,i. 
PELONOMIA Cooper, new genus 
(Greek pelos, mud; nomos, abode) 
Shell small, subrectangular in outline with the hinge as wide or wider than 
the midwidth ; planoconvex in profile ; pedicle valve with median fold and brachial 
valve with median sulcus. Surface finely multicostellate. Shell substance coarsely 
pseudopunctate. 
Pedicle valve with short interarea and rudimentary pseudodeltidium. Muscle 
area small, wider than long, bounded by short, thick dental plates and an anterior 
rim. 
Brachial valve with generalized interior consisting of a small, thickened but 
simple cardinal process and rounded chilidium. Notothyrial cavity shallow, 
bounded by short, delicate, primitive, rodlike brachiophores. Median ridge absent 
but its place marked by two rows of strong but distant nodes. Rest of surface 
coarsely but distantly granulose. 
Genotype.—Orthis delicatula Billings, Geol. Surv. Canada, Paleozoic fossils, 
vol. I, p. 217, 1865. 
Discussion.—This little genus is particularly characterized by its planoconvex 
form, coarse pseudopunctae, and the generalized character of the brachial in- 
terior. It is unique among these early brachiopods in lacking a median ridge or 
median septum. The exterior is plectambonitid, but the plectambonitid brachio- 
pods are generally characterized by one or more septa. Pelonomia suggests 
Eostrophomena Walcott in its shape and size, but that genus has a different cardi- 
nal process and possesses a median ridge. 
PELONOMIA DELICATULA (Billings) 
Plate 223, E, figures 8-10 
Orthis delicatula Brtu1ncs, Geol. Surv. Canada, Paleozoic fossils, vol. 1, p. 217, 1865. 
Figured hypotypes.—117557, 117558. 
Horizon and locality—Table Head series in Newfoundland: At Table Head; 
4 miles northeast of Portland Creek; 1 mile west of Aguathuna, Port-au-Port. 
Family PLECTAMBONITIDAE Kozlowski, 1929 
Strophomenoidea with normal or reversed convexity, usually finely costellate. 
Cardinal process simple. Brachial processes short and slender. Pseudodeltidium 
and chilidium present. 
Subfamily PLecTELLINAE Opik, 1930 
Finely costellate, with simple orthoid cardinal process, imperforate pseudo- 
deltidium. 
