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 1H83 ; 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 Kutokga's S. fissa (see Plate IV, figs. 81, ;-i3), 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 Siiiiplement, p. 21S. 1883. 



t Mr. Davidson described his Scottish species as having- ;i,ii '■.acuminated beak, perforated at its ex- 

 tremity by a small circular foraniinal aperture " (Geol. Mug.. 1S77, ji. 13). It is therefoi-e evident that the 

 Canadian species is widely different from iS. Scotica. 



