BRACHIOPODA. 
115 
We have before us an excellent series of specimens representing a species 
which has been described as Siphonotreta, from dark limestones intercalated 
between shales at Gloucester, Ontario; beds referred to the age of the 
Utica slate of New York. The first mention of these fossils was by Mr. J. F. 
Whiteaves, in a paper read before the Montreal meeting of the American 
Association for the Advancement of Science, in 1883 ; subsequently a more 
detailed account of their occurrence and association was given by Mr. H. M Ami, 
in the Ottawa Naturalist for December, 1887. To these gentlemen we are 
indebted for the opportunity of studying the fossils. Mr. Davidson, who ex¬ 
amined the Canadian specimens sent him by Mr. Whiteaves, identified 
them with his species Siphonotreta Scotica* but certain differences indicated by 
Mr. Ami induced the latter to propose therefor the varietal term Canadensis. 
The general features of these specimens and the numerous fine, smooth 
spines, indicate a close similarity to Davidson’s species; but in the material 
received from Mr. Ami are two pedicle-valves, one of which shows the ex¬ 
terior character of the pedicle-passage, and the other somewhat of its internal 
extension. The former shows this passage to be of precisely the character of 
that seen in Kutorga’s S. fissa (see Plate IY, figs. 31, 33), and the latter {idem, 
fig. 34) demonstrates that the interior extension of the sipho was carried as 
far forward as the center of the shell.f 
Upon comparison of these specimens with Kutorga’s description of S. fissa, 
we find an agreement in almost every particular; the shell has the “ depressed 
Terebratula-like form” in distinction from other species of the genus; the 
striae of growth, fine and sharp about the apex, become broad and thick toward 
the margins; the spaces between the rows of spines are smooth or crossed by 
extremely faint radiating lines; added to this is the character of the pedicle- 
groove, its floor being crossed by fine, successive growth-lines. Only in the 
relative number of the surface spines does there appear any difference. 
In the Russian species these are described as a mass of smooth, hair-like 
* Silurian Supplement, p. 21S. 1883. ^ 
f Mr. Davidson described his Scottish species as having’an “acuminated beak, perforated at its ex¬ 
tremity by a small circular foraminal aperture ” (Geol. Mag., 1877, p. 13). It is therefore evident that the 
Canadian species is widely different from /S'. Scot tea. 
