NEW BRACHIOPOD FROM BASE OF THE UTICA 
83 
Two other species of this genus, Tripleda spiriferoides, 
McCoy , 2 and Tnplecia gray ice, Davidson ,. 3 come from Great 
Britain, the former being found in the Caradoc of Wales and 
Ireland, and the latter in the same formation from Scotland and 
Wales. Tnplecia spiriferoides has a shorter pedicle beak than 
Oxopleda calhouni and a much wider hinge line, which features 
greatly alter the proportions of the cardinal area. Tnplecia 
spiriferoides also “is covered with numerous, very fine, radiating, 
thread-like, raised strise” in place of the larger and fewer pli- 
cations of Oxopleda calhouni. The average specimen of 
the Canadian species is somewhat wider and more gibbous. 
The Tripleda grayice is a smaller shell and not so wide in pro- 
portion to its length as either Tripleda spiriferoides or Oxopleda 
calhouni. The greatest width is nearer the front than in the 
Oxopleda calhouni , and the cardinal angles are more prominent, 
standing out like shoulders. The elevation of the fold in 
Tripleda grayice divides the shell into three almost equal lobes 
while the fold in calhouni is only about one-fourth of the whole 
width. The fold in Tripleda grayice is more rounded and the 
strise, like those of Tripleda ulricki, appear to continue down 
the sides instead of having the smooth, abrupt margins of the 
fold as in Oxopleda calhouni . The delthyrium of T. grayice is 
covered by a deltidium, “elevated along the middle ” in con- 
trast to the flat deltidium of 0 . calhouni. 
The Bohemian species, Orithisina cava , Barrande 3 , is more like 
Tnplecia ulrichi in general proportions. It has the less prom- 
inent and more rounded fold and sinus, with striations upon the 
sides as well as the top. The hinge line is wider than Oxopleda 
calhouni and the beak of the pedicle valve is shorter. 
Formation.—' The base of the Utica. 
Locality . — Ottawa, Canada: north of Carling avenue, between 
Rochester and Preston streets. The associated species are: 
Conularia trentonensis, Hall; Diplograptus sp. indt.; Leptoholus 
indgnis, Hall; Schizocrania filosa, Hall; Lingula progne, Billings; 
Dalmanella emacerata , Hall; Plectambonites sericeus (Sow r erby); 
British Silurian Brachiopoda, Vol. III. p. 275, pi. 37, figs. 3-7, 1886-71. Brit. Sil. 
Brach, Supplement Vol. V, p. 146, pi. 8, fig. 30, 1882-84. 
s British Silurian Brachiopoda, Vol. Ill, p. 198, pi. 24, figs. 31, 32; pi. 25, figs. 9-11, 
1886-71. Brit. Sil. Brach. Supplement, Vol. V, p. 144, pi. 8, fig. 32, 1882-84. 
*Syst6me Silurien du Centre de la Boh6me, Vol. Y, pi. 59, fig, iv, 1-7, 1879. 
24853 — 6$ 
